WO2026006279A1 - Active checked multiple displacer assembly - Google Patents

Abstract

A multi-displacer assembly includes multiple displacers that are driven out of phase with respect to each other. The assembly includes multiple pumps and each pump fluid downstream from the multi- displacer assembly. The multi-displacer assembly includes displacers that reciprocate to actively check fluid flow into and out of the multiple pumps.

Description

ACTIVE CHECKED MULTIPLE DISPLACER ASSEMBLY

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No. 63/664,444 filed June 26, 2024 and entitled “ACTIVE CHECKED MULTIPLE DISPLACER ASSEMBLY,” the disclosure of which is hereby incorporated by reference in its entirety.

BACKGROUND

The present disclosure concerns pumping. More specifically, the present disclosure concerns multiple displacer pumps.

Multiple piston pumps include multiple pistons that operate together to output a fluid flow from the pump. The pistons are driven out of phase with respect to each other. In such pumps, fluid is prevented from returning to a piston cavity by the use of ball checks. Ball checks use a spring to push (bias) the ball back into the ball seat. A ball check functions relative to fluid pressure, with the ball unseating and allowing fluid to pass towards the fluid outlet as the piston downstrokes creating fluid pressure. The ball reseats at the end of the piston downstroke, when the exiting fluid pressure becomes less relative to the force exerted by ball check spring and such that the piston chamber can be refilled.

SUMMARY

According to an aspect of the disclosure, a multi-displacer assembly includes an assembly body; a first assembly passage extending within the assembly body; a second assembly passage extending within the assembly body; a first fluid displacer configured to reciprocate along a first pump axis within a first displacer bore to pump fluid through a first pumping chamber; and a second fluid displacer configured to reciprocate along a second pump axis within a second displacer bore, the second displacer bore including a first transfer chamber and a second transfer chamber, wherein the first transfer chamber and the second transfer chamber are fluidly connected to the first pumping chamber, and wherein the second fluid displacer fluidly separates the first transfer chamber from the second transfer chamber within the second displacer bore. The second fluid displacer is configured to reciprocate along the second pump axis through an inlet open state in which the first assembly passage is fluidly connected to the first transfer chamber and the second transfer chamber is fluidly disconnected from the second assembly passage by the second fluid displacer, a closed state in which the first transfer chamber is fluidly disconnected from the first assembly passage and the second transfer chamber is fluidly disconnected from the second assembly passage, and an outlet open state in which the first transfer chamber is fluidly disconnected from the first assembly passage and the second transfer chamber is fluidly connected with the second assembly passage.

According to an additional or alternative aspect of the disclosure, a multidisplacer assembly includes an assembly body; a first assembly passage extending within the assembly body; a second assembly passage extending within the assembly body; a first fluid displacer configured to reciprocate along a first reciprocation axis within a first displacer bore to pump fluid through a first pumping chamber; and a second fluid displacer configured to reciprocate along a second reciprocation axis within a second displacer bore, the second displacer bore including a first transfer chamber and a second transfer chamber, the first transfer chamber and the second transfer chamber are fluidly connected to the first pumping chamber, and the second fluid displacer fluidly separating the first transfer chamber from the second transfer chamber within the second displacer bore. The second fluid displacer is configured to fluidly connect and disconnect the first assembly passage from the first transfer chamber, and the second fluid displacer is configured to fluidly connect and disconnect the second assembly passage from the second transfer chamber.

According to another additional or alternative aspect of the disclosure, a multi-displacer assembly includes an assembly body; a first assembly passage extending within the assembly body; a second assembly passage extending within the assembly body; and a plurality of fluid displacers, each fluid displacer of the plurality of fluid displacers configured to reciprocate on a respective reciprocation axis within a respective displacer bore in the assembly body. Each fluid displacer of the plurality of fluid displacers is configured to displace fluid from the first assembly passage to the second assembly passage, and each fluid displacer of the plurality of fluid displacers is configured as a checking displacer configured to actively check fluid flow into and out of a pumping chamber of an adjacent fluid displacer of the plurality of fluid displacers. A pumping flowpath of the adjacent fluid displacer flows in a single direction from the first assembly passage, to a first transfer chamber disposed along the reciprocation axis of the checking fluid displacer, to the pumping chamber of the adjacent fluid displacer, to a second transfer chamber disposed along the reciprocation axis of the checking fluid displacer and spaced axially from the first transfer chamber, and then to the second assembly passage.

According to yet another additional or alternative aspect of the disclosure, a displacer for a multi-displacer assembly, the displacer configured to provide active checking to a pumping displacer of the multi-displacer assembly, the displacer including a proximal shaft portion extending along a reciprocation axis and having an upper diameter; a distal shaft portion extending along the reciprocation axis, spaced axially from the proximal shaft portion and having a lower diameter; a central shaft portion extending along the reciprocation axis, disposed axially between the proximal shaft portion and the distal shaft portion, and having a central diameter; a first chamber connector disposed axially between the proximal shaft portion and the central shaft portion, a diameter of the first chamber connector smaller than the upper diameter; and a second chamber connector disposed axially between the central shaft portion and the distal shaft portion, a diameter of the second chamber connector smaller than the lower diameter.

According to yet another additional or alternative aspect of the disclosure, a pump cap for a pump of a multi-displacer assembly includes a cap body having a top side configured to be oriented in a first axial direction along an axis, and a bottom side opposite the top side; a chamber bore within the cap body and extending along the axis, the chamber bore at least partially defining a pumping chamber; a first feed passage extending between a first outer port on an exterior of the cap body and the chamber bore; and a second feed passage extending between a second outer port on the exterior of the pump cap and the chamber bore.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing flow passages for a multi-displacer assembly.

FIG. 2 is an isometric view of a multi-displacer pumping assembly.

FIG. 3 is a cross-sectional view taken along line A-A in FIG. 2. FIG. 4 is a cross-sectional view taken along line B-B in FIG. 2.

FIG. 5A is a cross-sectional view taken along line C-C in FIG. 2. FIG. 5B is a cross-sectional view taken along line C-C in FIG. 2. FIG. 5C is a cross-sectional view taken along line C-C in FIG. 2. FIG. 5D is a cross-sectional view taken along line C-C in FIG. 2. FIG. 5E is a cross-sectional view taken along line D-D in FIG. 2. FIG. 5F is a cross-sectional view taken along line D-D in FIG. 2. FIG. 5G is a cross-sectional view taken along line D-D in FIG. 2. FIG. 6A is an isometric view of a pump cap.

FIG. 6B is a cross-sectional view of the pump cap taken along line B-B in FIG. 6A. DETAILED DESCRIPTION

The present disclosure relates generally to displacement assemblies. According to aspects of the present disclosure a multi-displacer assembly includes multiple displacers that reciprocate out of phase with respect to each other to pump a fluid. The multi-displacer assembly includes multiple pumps that each include a fluid displacer that reciprocates to pump the fluid. The multi-displacer assembly includes active checking in which reciprocating displacers perform checking of passageways for inlet and outlet flows from the individual pumps. The checking displacer can, in some examples, simultaneously pump the fluid. As such, the displacer of one pump of the assembly provides checking for directing flow into and out of another one of the pumps of the assembly while also pumping the fluid.

Multi-displacer assemblies according to the present disclosure do not require ball valves or other valves to regulate the inflow and outflow of fluid, unlike traditional pumps. The displacers of the multiple pumps of the assembly perform the fluid checking for others of the multiple pumps. According to aspects of the present disclosure, each of the individual pumps includes a pumping chamber through which the fluid displacer of that pump pumps the fluid. The multiple pumps are fluidly connected to each other such that one pump receives fluid from and outputs fluid to another of the pumps. The pumps are fluidly connected such that one pump pumps through a displacer bore of another pump within which the displacer of that pump reciprocates. The pumping chamber of a first pump is fluidly connected to a second pump by fluid pathways between the first and second pumps. The fluid pathways direct fluid from a first flow chamber of the second pump to the pumping chamber of the first pump and then to a second flow chamber of the second pump. The first and second flow chambers are fluidly connected to inlet and outlet passages of the multi-displacer assembly. The fluid displacer of the second pump fluidly separates the flow chambers. The fluid displacer of the second pump reciprocates to simultaneously pump fluid through the pumping chamber of the second pump and alternatingly fluidly connect the pumping chamber of the first pump to the first and second flow chambers of the second pump.

The multi-displacer assembly includes multiple transfer chambers within the displacer bore of each pump. A first transfer chamber of the second pump is fluidly connectable to an inflow to the multi-displacer assembly to provide fluid for the first pump. A second transfer chamber of the second pump is fluidly connectable to an outflow of the multi-displacer assembly to receive fluid from the first pump and output that fluid from the assembly. The first and second transfer chambers are fluidly isolated from each other within the second displacer bore. Such a configuration can provide for first-in, first-out flow without requiring additional checks.

The fluid displacer of a pump of the multi-displacer pumping assembly is configured to maintain fluid separation between flow chambers of that pump. The fluid displacer can include chamber connectors configured to fluidly connect the pumping chamber of another pump with the inflows and outflows of the multi-displacer assembly. The chamber connectors can be formed on an exterior of the fluid displacer, within an interior of the fluid displacer, or a combination thereof. The fluid displacer can include multiple chamber connectors. An inlet chamber connector of a fluid displacer can be configured to fluidly connect the assembly inflow to a first transfer chamber of that pump. An outlet chamber connector of the fluid displacer can be configured to fluidly connect the assembly outflow to a second transfer chamber of that pump.

The fluid displacers of the multiple pumps of the multi-displacer assembly can be driven out of phase with respect to each other. Driving the fluid displacers out of phase facilitates continuous outflow from the multi-displacer assembly. According to aspects of the disclosure, the fluid displacers can be driven by drive, such as a wobble drive, a cam drive, or any suitable drivetrain that allows for phasing of the multiple fluid displacers. In some examples, the multi-displacer assembly with active checking can be used for fluid metering, such as with liquid proportioning in the liquid finishing market. In some examples, the multi-displacer pumping assembly with active checks may be driven in reverse with compressed air to serve as an air motor (i.e., outputting a rotational force via a drive).

Components can be considered to radially overlap when those components are disposed at common axial locations along an axis. A radial line extending from the axis will extend through each of the radially overlapping components. Components can be considered to axially overlap when those components are disposed at common radial and circumferential locations relative to an axis such that an axial line parallel to the axis extends through the axially overlapping components. Components can be considered to circumferentially overlap when aligned about the axis, such that a circle centered on the axis passes through the circumferentially overlapping components.

FIG. 1 is a schematic diagram of a multi-displacer assembly 10. The multidisplacer assembly includes pumps 12a-12d (collectively referred to herein as “pump 12” or “pumps 12”), inlet pathway 22, and outlet pathway 24. Each pump 12 includes pumping chamber 14, inlet chamber 16, and outlet chamber 18. Transfer pathways 20a, 20b extend between pumps 12.

Multi-displacer assembly 10 is configured to output a fluid for dispensing on a substrate. For example, multi-displacer assembly 10 can be configured to dispense higher viscosity fluids (e.g., sealant, adhesive, foam, gasketing material, among other options). In some examples, the multi-displacer assembly 10 can be configured to produce sufficient outlet fluid pressure to create fluid atomization at a nozzle outlet, thereby allowing the system to be used in airless spraying applications, such as disclosed in United States Patent No. 9,914,141 (‘141 Patent) and United States Pre-Grant Publication 2017/0165692, the disclosure of which is herein incorporated by reference in its entirety.

Multi-displacer assembly 10 includes active checking in which the fluid checks are provided by a portion of the pump drivetrain, typically by a portion of a fluid displacer itself relative to a pump body. In some examples, the active checking is provided by the fluid displacer (e.g., via different diameters of a piston along select lengths of the piston) blocking the inlet port (at certain phase(s)) and the outlet port (at certain phase(s)). Active checking may provide more exact amounts of fluid dispense (e.g., more exact doses). Active checking can also provide for smoother fluid flow by eliminating vibration generated by a ball reseating to close flowpaths in assemblies including ball check valves.

Pumps 12a-12d are fluidly connected to inlet pathway 22. Inlet pathway 22 provides flow of fluid to each of pumps 12a-12d. The pumps 12a-12d are fluidly connected to a common inlet pathway 22. In some examples, the fluid can be provided to multi-displacer assembly 10 under pressure such that inlet pathway 22 provides a pressurized inflow to multi-displacer assembly 10. Pumps 12a-12d are also fluidly connected to outlet pathway 24. Outlet pathway 24 receives fluid output by each of pumps 12a-12d. The pumps 12a-12d are fluidly connected to a common outlet pathway 24. The multi-displacer assembly 10 can be configured to receive a common inflow and to output a common outflow. In some examples, multi-displacer assembly 10 can be configured to output the pumped fluid at a pressure lower than the inlet pressure of the fluid received by multi-displacer assembly 10.

Pumps 12a-12d include fluid displacers that are configured to reciprocate to pump fluid and to provide active checking for others of the pumps 12. The fluid displacers can be configured as pistons, plungers, etc. It is understood that, while fluid displacers may be referred to as pistons in this disclosure, such description is equally applicable to plunger type pumping. The fluid displacers are reciprocated through pump cycles. Each pump cycle includes a first stroke in a first direction along the reciprocation axis of the fluid displacer and a second stroke in a second direction along the reciprocation axis of the fluid displacer. The first stroke can increase a volume of the pumping chamber 14 such that fluid fills into the pumping chamber 14. The second stroke can decrease a volume of the pumping chamber 14 such that fluid is output from the pumping chamber 14.

Inlet chambers 16 of each pump 12a-12d are fluidly connected to inlet pathway 22. The inlet chambers 16 can be at least partially defined by a fluid displacer of the pump 12. The inlet chambers 16 can be formed within a displacer cavity of the pump 12 within which the fluid displacer of the pump 12 reciprocates. The displacer cavity can also be referred to as a displacer bore or pump bore. The inlet chambers 16 receive an inflow from inlet pathway 22. Outlet chambers 18 of each pump 12a-12d are fluidly connected to outlet pathway 24. The outlet chambers 18 can be at least partially defined by the fluid displacer of the pump 12. The outlet chambers 18 can be formed within the displacer cavity of the pump 12 within which the fluid displacer of the pump 12 reciprocates. Outlet chambers 18 are configured to provide an outflow to outlet pathway 24. The inlet chamber 16 and the outlet chamber 18 are maintained as fluidly separated throughout operation by the fluid displacer of the pump 12.

It is understood that multi-displacer pumping assembly 10 can be configured for dual directional flow. For example, running a drive that reciprocates the fluid displacers in a first direction can cause the inlet pathway 22 to provide the fluid to the multi-displacer pumping assembly 10 such that fluid is output through outlet pathway 24. Running the drive in a second opposite direction can cause the multi-displacer pumping assembly 10 to pump fluid from outlet pathway 24 to inlet pathway 22 such that outlet pathway 24 provides the fluid to pumps 12a-12d and inlet pathway 22 receives the fluid output by pumps 12a-12d. The inlet pathway 22 and outlet pathway 24 can be referred to as pump pathways of the pump 12 as either of the inlet pathway 22 and the outlet pathway 24 can provide fluid to or receive fluid from pumps 12a-12d.

Pumping chambers 14 are formed in each pump 12a-12d. The fluid displacer of the pump 12a-12b reciprocates on a reciprocation axis to pump the fluid through the pumping chamber 14. The pumping chamber 14 can be at least partially defined by the fluid displacer and the displacer cavity within which the fluid displacer reciprocates. Transfer pathways 20a, 20b extend between and fluidly connect the various pumps 12a-12d of the multi-piston pumping assembly 10. In the example shown, each pump 12 is connected to another one of the pumps 12 by a pair of transfer pathways 20a, 20b. Transfer pathways 20a fluidly connect the inlet chamber 16 of a checking one of the pumps 12 with the pumping chamber 14 of another pump 12 for which flow is being checked by the checking one of the pumps 12. Transfer pathways 20b fluidly connect the outlet chamber 18 of the checking one of the pumps 12 with the pumping chamber 14 of the other pump for which flow is being checked by the checking one of the pumps 12.

During operation, the pumps 12a-12d are operated out of phase such that the fluid displacers of the pumps 12 are at varying locations throughout their respective pump strokes relative to the other fluid displacers. Fluid is provided to multi-displacer pumping assembly 10 from an upstream fluid supply, which can be pressurized. The fluid flows through inlet pathway 22 and to inlet chambers 16 of the pumps 12a-12d.

For pump 12a, the fluid displacer of pump 12d fluidly connects the inlet chamber 16 of pump 12d with transfer pathway 20a with the fluid displacer of pump 12a at or near the end of a discharge stroke in which fluid is output from pumping chamber 14 of pump 12a. The piston of pump 12a begins to move through a fill stroke and fluid flows from the inlet chamber 16 of pump 12d through the transfer pathway 20a between the inlet chamber 16 of pump 12d and the pumping chamber 14 of pump 12a and into the pumping chamber of pump 12a. The piston of pump 12a turns over after the fill stroke and begins a discharge stroke. The piston of pump 12d shifts to fluidly disconnect the inlet chamber 16 of pump 12d from the pumping chamber 14 of pump 12a and to fluidly connect the outlet chamber 18 of pump 12d with the pumping chamber 14 of pump 12a. The fluid displacer of pump 12a drives the fluid out of pumping chamber 14 through transfer pathway 20b and to outlet chamber 18 of pump 12d. The fluid is then output to outlet pathway 24. In some examples, the fluid displacer of pump 12d can be considered to form a shuttle valve for directing of fluid to the pumping chamber 14 of pump 12a.

It is understood that while operation of pump 12a is discussed above, pumps 12b-12d can operate in the same or similar manner. In the example shown, pump 12b is configured to receive fluid from inlet chamber 16 of pump 12a and output fluid through outlet chamber 18 of pump 12a; pump 12c is configured to receive fluid from inlet chamber 16 of pump 12b and output fluid through outlet chamber 18 of pump 12b; pump 12d is configured to receive fluid from inlet chamber 16 of pump 12c and output fluid through outlet chamber 18 of pump 12c. While multi-displacer pumping assembly 10 is described such that each pump 12 performs both fluid displacing and active checking, it is understood that not all examples are so limited. In some examples, a first subset of the pumps 12 perform fluid displacement while a second subset of the pumps 12 provide active checking for the first subset of pumps 12. In such an example, the first subset of pumps can be considered to include pumping displacers and the second set of pumps can be considered to include checking displacers. For example, the reciprocator (e.g., piston, plunger, etc.) of pump 12a can be configured to pump fluid through the pumping chamber 14 of pump 12a and the reciprocator of pump 12d can be configured to provide active checking for pump 12a but without displacing fluid. Pump 12c can be configured to pump fluid through the pumping chamber 14 of pump 12c and pump 12b can be configured to provide active checking for pump 12c but without displacing fluid. In such an example, pumps 12a, 12c form the first subset that perform fluid displacement while pumps 12b, 12d perform the second subset that perform active checking.

Multi-displacer pumping assembly 10 provides significant advantages. The fluid displacers of the pumps 12 function to fluidly connect and disconnect pumping chambers 14 of others of the pumps 12 from the inlet pathway 22 and outlet pathway 24. The fluid displacers further reciprocate to pump the fluid. The fluid displacers thereby perform dual operation by both providing active checking for flow of another pump 12 and providing pumping for the pump 12 of the fluid displacer. The fluid displacers can be operated out of phase such that at least one of the pumps 12 is outputting fluid to outlet pathway 24 at any given time during operation, thereby providing a steady and continuous outflow from the multi-displacer pumping assembly 10.

Multi-displacer pumping assembly 10 can be utilized across multiple dispense operations and for multiple purposes. For example, multi- displacer pumping assembly 10 can be configured for dispensing of a high viscosity fluid (e.g., without limitation, a sealant, adhesive, foam, or gasketing material). In some examples, multidisplacer pumping assembly 10 is configured to produce sufficient outlet fluid pressure to create fluid atomization at a nozzle outlet (not shown), thereby allowing the system to be used in airless spraying applications. In some examples, multi- displacer pumping assembly 10 can be used as a meter (i.e., a dosing pump), such as the fluid meters (or dosing pumps) used with a liquid proportioner. In some examples, multi- displacer pumping assembly is not used as a fluid pump but instead as an air motor when driven in reverse direction with compressed air in order to create a rotational force (or multiple, phased linear forces if not coupled with a drive).

FIG. 2 is an isometric view of multi-piston pumping assembly 10. The assembly body 30 is shown as translucent in FIG. 2 to illustrate the positions of various flow pathways within multi-displacer assembly 10. FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 2. FIG. 4 is a cross-sectional view taken along line 4-4 in FIG. 2. FIG. 5A is a cross-sectional view taken along line C-C in FIG. 2. FIG. 5B is a cross- sectional view taken along line C-C in FIG. 2. FIG. 5C is a cross-sectional view taken along line C-C in FIG. 2. FIG. 5D is a cross-sectional view taken along line C-C in FIG. 2. FIG. 5E is a cross-sectional view taken along line D-D in FIG. 2. FIG. 5F is a cross- sectional view taken along line D-D in FIG. 2. FIG. 5G is a cross-sectional view taken along line D-D in FIG. 2. FIGS. 2-5F will be discussed together with continued reference to FIG. 1. The multi-displacer assembly 10 includes drive 26, a plurality of pumps 12, pump pathway 28a (best seen in FIG. 3A), pump pathway 28b (best seen in FIG. 3B), and assembly body 30. Pumps 12a-12d each include pumping chamber 14, flow chamber 32a, flow chamber 32b, transfer chamber 34a, transfer chamber 34b, fluid displacer 34, displacer bore 38, seal support 40, chamber cage 42, displacer seals 44a, 44b, routing seals 46a, 46b, chamber seal 48, and pump cap 52. Transfer pathways 20a, 20b extend between pumps 12.

Pump 12a and pump 12b are shown and discussed in detail in FIGS. 5A-5F, but it is understood that the active checking and flowpaths can be the same as between each of the pumps 12a-12d, such as discussed above with regard to FIG. 1.

Assembly body 30 supports other components of multi-displacer pumping assembly 10. In the example shown, the assembly body 30 forms a pump body for each pump 12. The displacer bore 38 of each pump 12 is formed in assembly body 30. In some examples, the fluid passages through assembly body 30 can be formed through a monolithic block of the assembly body 30. In the example shown, assembly body 30 includes fluid housing 54 and end caps 56a, 56b. The fluid pathways are formed in fluid housing 54.

End caps 56a, 56b are connected to fluid housing 54. In the example shown, one end cap 56a is disposed at a first end of fluid housing 54 and another end cap 56b is disposed at a second end of fluid housing 54. End cap 56a can retain structure within assembly body 30. In the example shown, end cap 56a retains chamber cage 42 within displacer bore 38. Fluid displacers 36 extend through end cap 56a to connect to drive 26. End cap 56b cap retain structure within assembly body 30. In the example shown, end cap 56b retains pump caps 52 within displacer bores 36. End caps 56a, 56b can be connected to fluid housing 54 in any desired manner, such as by fasteners, such as threaded fasteners, such as bolts among other options.

For each pump 12, the fluid displacer 34 is at least partially disposed within the assembly body 30. The fluid displacer 34 is elongate along a reciprocation axis RA for that fluid displacer 34. In the example shown, the fluid displacers 36 each reciprocate on a reciprocation axis RA that is radially offset from and parallel to the other reciprocation axes RA. The fluid displacers 36 can be configured as pistons, plungers, or other type of fluid mover.

The fluid displacer 34 is connected to drive 26 to receive a reciprocating input from drive 26. Drive 26 is configured to convert a rotational input to a linear outlet and/or to receive a linear input and provide a rotational output. In the example shown, the drive 26 is formed as a wobble drive through it is understood that other configurations are possible. The rotational input for the wobble drive (or similar drive, e.g., cam) may be provided by various motors, such as described in Paragraph [0050] of United States Patent Application Publication 2017/0165692, assigned to Grace Minnesota Inc., with the disclosure of U.S. Patent Application Publication 2017/0165692 incorporated by reference in its entirety. The drive 26 is configured to move the fluid displacers 36 of the pumps 12 out of phase relative to each other. The drive 26 can be connected to a motor output shaft that provides rotational input to the drive 26. The drive 26 is configured to convert that rotational input into reciprocating linear motion that is provided to fluid displacers 36 to displace fluid displacers 36 and cause pumping by the multi-displacer assembly 10. It is understood that in various examples, the displacers 36 can be moved by fluid through the assembly body 30, providing a linear input to drive 26 that the drive 26 can convert to a rotational output.

Pump pathways 28a, 28b are formed in assembly body 30. One of pump pathways 28a, 28b provides an inlet passage (e.g., inlet pathway 22 (FIG. 1)) for multidisplacer pumping assembly 10 and the other one of pump pathways 28a, 28b provides an outlet passage (e.g., outlet pathway 24 (FIG. 1)) for multi-displacer pumping assembly 10. In the example shown, each displacer bore 38 is fluidly connected to the both pump pathways 28a, 28b such that each pump 12 receives an inflow from a common flowpath and outputs an outflow to a common flowpath. Rotating drive 26 in a first rotational direction will cause pump 12 to intake fluid through pump pathway 28a and output fluid through pump pathway 28b. Rotating drive 26 in a second rotational direction opposite the first rotational direction will cause pump 12 to intake fluid through pump pathway 28b and output fluid through pump pathway 28a.

Assembly port 60a is open to an exterior of assembly body 30. The assembly port 60a can connect to a hose or other line for providing fluid to or receiving fluid from pump pathway 28a. Pump pathway 28a is fluidly connected to the displacer bore 38 of each pump 12a-12d. As such, pump pathway 28a can provide fluid to or receive fluid from each pump 12a-12d. Pump pathway 28a is fluidly connected to the flow chamber 32a of each pump 12.

Common passage 59a extends between assembly port 60a and feed bores 58a. Feed bores 58a extend to each displacer bore 38 to provide fluid communication between assembly port 60a and each displacer bore 38. The feed bores 58a extend radially outward from a central axis CA of the multi-displacer assembly 10. The central axis CA can be disposed coaxially with drive axis DA on which the drive 26 rotates. The feed bores 58a can be considered to radiate from a distal end of common passage 59a. In the example shown, the feed bores 58a are formed by a pair of cross-bores that are formed in the fluid housing 54. The ends of the cross-bores through the exterior of fluid housing 54 are closed with plugs. The cross-bores can be disposed orthogonal to each other. Each feed bore 58a can extend orthogonal to one or more of the other feed bores 58a and coaxial with another of the feed bores 58 a.

Assembly port 60b is open to an exterior of assembly body 30. The assembly port 60b can connect to a hose or other line for providing fluid to or receiving fluid from pump pathway 28b. Pump pathway 28b is fluidly connected to the displacer bore 38 of each pump 12a-12d. As such, pump pathway 28b can provide fluid to or receive fluid from each pump 12a-12d. Pump pathway 28b is fluidly connected to the flow chamber 32b of each pump 12.

Common passage 59b extends between assembly port 60b and feed bores 58b. Feed bores 58b extend to each displacer bore 38 to provide fluid communication between assembly port 60b and each displacer bore 38. The feed bores 58b extend radially outward from a central axis CA of the multi-displacer assembly 10. The feed bores 58b can be considered to radiate from a distal end of the common passage 59b. In the example shown, the feed bores 58b are formed by a pair of cross-bores that are formed in the fluid housing 54. The ends of the cross-bores through the exterior of fluid housing 54 are closed with plugs. The cross-bores can be disposed orthogonal to each other. Each feed bore 58b can extend orthogonal to one or more of the other feed bores 58b and coaxial with another of the feed bores 58b.

For each pump 12, chamber cage 42 is at least partially disposed within displacer bore 38. Chamber cage 42 includes apertures therethrough that allow fluid to flow through chamber cage 42. Seal support 40 is at least partially disposed within displacer bore 38. Seal support 40 at least partially defines the pumping chamber 14.

Chamber cage 42 is disposed within the displacer bore 38. The chamber cage 42 at least partially defines various chambers within the displacer bore 38. Chamber cage 42 includes apertures therethrough that allow fluid to flow through chamber cage 42. The chamber cage 42 can support one or more seals that dynamically interface with and seal against the fluid displacer 36. Chamber cage 42 can further support one or more static outer seals 100 that seal against the fluid housing 54 to prevent fluid leakage around the exterior of chamber cage 42. It is understood that chamber cage 42 can be formed by one or more separate structures that are disposed within displacer bore 38. In the example shown, each of flow chambers 32a, 32b and transfer chambers 34a, 34b within a single displacer bore 38 are at least partially defined by the chamber cage 42 within that displacer bore 38.

The fluid displacer 34 of each pump 12 is configured to reciprocate within the displacer bore 38 of that pump 12. The fluid displacer 34 can also be referred to as a reciprocator. It is understood that in some examples, pump 12b may not include a pumping chamber 14 and may instead be configured such that the fluid displacer 34 of pump 12b reciprocates to provide active checking to pump 12a but without pumping fluid through a fluid chamber. In some such examples, pump 12a may perform fluid displacement without providing active checking, such that pump 12a may not include flow chambers 32a, 32b, transfer chambers 34a, 34b, or corresponding sealing elements.

The fluid displacer 34 interfaces with various seals within the displacer bore 38 to divide the displacer bore 38 into chambers and to route fluid. In the example shown, displacer seal 44a interfaces with fluid displacer 34 and at least partially defines flow chamber 32a. Displacer seal 44a is configured to engage and seal against fluid displacer 34 throughout operation. Displacer seal 44a is configured to prevent fluid from leaking out of fluid housing 38 between fluid displacer 34 and fluid housing 38. In the example shown, displacer seal 44a is supported by and disposed between fluid displacer 36 and chamber cage 42. Displacer seal 44a is a dynamic seal in that fluid displacer 34 moves relative to displacer seal 44a during operation while maintaining a sealed interface with displacer seal 44a. Displacer seal 44a is formed as a u-cup seal in the example shown, though it is understood that other configurations are possible.

Displacer seal 44b is disposed within assembly body 38. Displacer seal 44b is disposed within displacer bore 38. Displacer seal 44b interfaces with fluid displacer 34 and at least partially defines pumping chamber 14. In the example shown, displacer seal 44b also at least partially defines transfer chamber 34b. Displacer seal 44b is configured to engage and seal against fluid displacer 34 throughout operation. Displacer seal 44b is configured to prevent fluid from leaking between the pumping chamber 14 of the displacer 34 and the fluid passages of the pump 12 that the displacer 34 is providing checking for. In the example shown, the displacer seal 44b fluidly separates the pumping chamber 14 and the transfer chamber 34b. Displacer seal 44b is a dynamic seal in that fluid displacer 34 moves relative to displacer seal 44b during operation while maintaining a sealed interface with displacer seal 44b. In the example shown, displacer seal 44b is supported by seal support 40 and disposed between fluid displacer 36 and seal support 40. An outer seal 100 is disposed between seal support 40 and fluid housing 54 to prevent fluid leakage therebetween. Displacer seal 44b can be formed by one or more seals. In the example shown, displacer seal 44b is formed by a pair of u-cup seals, though it is understood that other configurations are possible.

Chamber seal 48 is disposed within assembly body 30. Chamber seal 48 is disposed within displacer bore 38 and interfaces with fluid displacer 36. Chamber seal 48 at least partially defines transfer chamber 34a and flow chamber 32b. Chamber seal 48 forms a dynamic seal interface with fluid displacer 36. Chamber seal 48 is configured to engage with and seal against fluid displacer 36 throughout operation. Chamber seal 48 does not disengage from fluid displacer 36 and fluidly isolates the flow provided to the adjacent pump 12 from the flow from the adjacent pump 12. In the example shown, the chamber seal 48 is disposed directly between and fluidly isolates the transfer chamber 34a and flow chamber 32b. Chamber seal 48 can be formed by one or more seals. In the example shown, chamber seal 48 is formed by a pair of u-cup seals, though it is understood that other configurations are possible. The chamber cage 42 can be considered to form a seal support for chamber seal 48 in the example shown.

The transfer chambers 34a, 34b are not directly fluidly connected, such as by a direct pathway within the displacer bore 38 of those transfer chambers 34a, 34b. The transfer chambers 34a, 34b within a single displacer bore 38 are fluidly isolated from each other within that displacer bore 38 throughout operation of the pump 12. The transfer chambers 34a, 34b are only fluidly connected through the pumping chamber 14 of an adjacent pump 12.

Pumps 12 are configured such that fluid displacer 34 moves into and out of engagement with routing seals 46a, 46b to provide the active checking for another of pumps 12. Each routing seal 46a, 46b is engaged with fluid displacer 34 during certain phases of operation and is disengaged from fluid displacer 34 during other phases of operation. In the example shown, at least one of routing seals 46a, 46b is in sealing engagement with fluid displacer 34 throughout operation. In various operational phases, both routing seals 46a, 46b are engaged with fluid displacer 36 such that both an inlet and outlet valve for the pumping fluid displacer 36 are closed.

Routing seal 46a is disposed between flow chamber 32a and transfer chamber 34a. Routing seal 46a is disposed axially between the flow chamber 32a and transfer chamber 34a. Fluid displacer 34 engages routing seal 46a to fluidly isolate flow chamber 32a and transfer chamber 34a. Fluid displacer 36 disengages from the routing seal 46a to fluidly connect flow chamber 32a and transfer chamber 34a. The fluid displacer 36 engaging routing seal 46a closes a check for an adjacent pump 12 and the fluid displacer 36 disengaging from routing seal 46a opens a check for the adjacent pump 12.

Routing seal 46b is disposed between flow chamber 32b and transfer chamber 34b. Routing seal 46b is disposed axially between the flow chamber 32b and transfer chamber 34b. Fluid displacer 34 engaging routing seal 46b fluidly isolates flow chamber 32b and transfer chamber 34b. Fluid displacer 36 disengages from the routing seal 46b to fluidly connect flow chamber 32b and transfer chamber 34b. The fluid displacer 36 engaging routing seal 46b closes a check for an adjacent pump 12 and the fluid displacer 36 disengaging from routing seal 46b opens a check for the adjacent pump 12.

Fluid displacer 36 includes displacer shaft 62, proximal shaft portion 64, central shaft portion 66, distal shaft portion 68, and chamber connectors 70a, 70b. Displacer shaft 62 is elongate along the reciprocation axis RA. Displacer shaft 62 extends between drive end 72 and fluid end 74. In some examples, displacer shaft 62 can be formed monolithically. In some examples, displacer shaft 62 can be formed from various components connected together. In the example shown, displacer shaft 62 includes a head 73 that forms drive end 72 that is formed separately from a shaft body 75 that is connected to the head.

Drive end 72 is configured to interface with drive 26 to receive a linear input from drive 26. In some examples, drive end 72 can be connected to drive 26 such that drive 26 can exert a driving force in both axial directions ADI, AD2. Fluid end 74 can interface with fluid within pumping chamber 14 to pressurize and displace the fluid.

In some examples, drive 26 can be connected to displacer 36 such that drive 26 can exert a driving force in axial direction AD2 to move the displacer 36 through a pressure stroke, while the drive is drivingly disconnected from the displacer 36 in an opposite direction such that the drive 26 does not pull the displacer 36 through a fill stroke. In such examples, the feed pressure of the fluid provided to multi-displacer assembly 10 and thus to pumping chamber 14 can move the displacer 36 through the fill stroke. The drive 26 can interface with the displacer 36 during the fill stroke to limit displacement of displacer 36 in axial direction ADI.

In the example shown, drive 26 is formed as a wobble drive. Drive 26 includes an eccentric 27 on a driveshaft and a plate 29 that is caused to wobble by the eccentric 27. In the example shown, the plate 29 is formed as a ring with a plurality of posts, the posts connecting to the drive ends 72 of the various displacers 36.

Proximal shaft portion 64 interfaces with displacer seal 44a and extends to contact fluid within displacer bore 38. Proximal shaft portion 64 is sized to maintain contact with displacer seal 44a throughout a full reciprocation cycle of displacer 36. Proximal shaft portion 64 is in sealing contact with displacer seal 44a throughout the full pressure stroke and the full fill stroke of the fluid displacer 36. Proximal shaft portion 64 is configured to move into and out of contact with routing seal 46a to open and close the flowpath between pump pathway 28a and transfer chamber 34a.

Central shaft portion 66 is spaced in axial direction AD2 from proximal shaft portion 64. Proximal shaft portion 64 is disposed axially closer to drive 26 than central shaft portion 66. Central shaft portion 66 interfaces with chamber seal 48. Central shaft portion 66 is sized to maintain contact with chamber seal 48 throughout a full reciprocation cycle of displacer 36. Central shaft portion 66 is in sealing contact with chamber seal 48 throughout the full pressure stroke and the full fill stroke. Central shaft portion 66 projects through transfer chamber 34a and into flow chamber 32b. As such, central shaft portion 66 can contact fluid both upstream and downstream of a pumping chamber 14. Central shaft portion 66 does not contact either routing seal 46a, 46b throughout reciprocation of the fluid displacer 36.

Distal shaft portion 68 is spaced in axial direction AD2 from proximal shaft portion 64. Distal shaft portion 68 is spaced in axial direction AD2 from central shaft portion 66. Central shaft portion 66 is disposed axially between proximal shaft portion 64 and distal shaft portion 68. Proximal shaft portion 64 and central shaft portion 66 are disposed axially closer to drive 26 than distal shaft portion 68.

Distal shaft portion 68 interfaces with displacer seal 44b. Distal shaft portion 68 is sized to maintain contact with displacer seal 44b throughout a reciprocation cycle of displacer 36. Distal shaft portion 68 is in sealing contact with displacer seal 44b throughout the full pressure stroke and the full fill stroke. Distal shaft portion 68 can extend into and, in some states, through transfer chamber 34b. Distal shaft portion 68 projects into pumping chamber 14 and contacts fluid within pumping chamber 14. Distal shaft portion 68 extends to fluid end 74 of fluid displacer 36. Reciprocation of distal shaft portion 68 within pumping chamber 14 causes pumping by the pump 12. Distal shaft portion 68 is configured to move into and out of contact with routing seal 46b to open and close the flowpath between pump pathway 28b and transfer chamber 34b.

Chamber connector 70a is disposed axially between proximal shaft portion 64 and central shaft portion 66. Chamber connector 70a extends between and connects proximal shaft portion 64 and central shaft portion 66 in the example shown. Chamber connector 70a is configured to fluidly connect flow chamber 32a and transfer chamber 34a. In the example shown, chamber connector 70b is formed as a reduced diameter portion of fluid displacer 36 relative to central shaft portion 66 and proximal shaft portion 64. The chamber connector 70a has a reduced diameter relative to proximal shaft portion 64 to facilitate engagement and disengagement of proximal shaft portion 64 from routing seal 46a. Chamber connector 70a can be formed as a groove on fluid displacer 36. The groove can extend fully annularly about the reciprocation axis RA.

Chamber connector 70a radially overlapping with routing seal 46a disconnects displacer 36 from routing seal 46a. Chamber connector 70a radially overlapping with routing seal 46a fluidly connects flow chamber 32a and transfer chamber 34a.

Chamber connector 70b is disposed axially between distal shaft portion 68 and central shaft portion 66. Chamber connector 70b extends between and connects distal shaft portion 68 and central shaft portion 66 in the example shown. Chamber connector 70b is configured to fluidly connect flow chamber 32b and transfer chamber 34b. In the example shown, chamber connector 70b is formed as a reduced diameter portion of fluid displacer 36 relative to central shaft portion 66 and distal shaft portion 68. The chamber connector 70b has a reduced diameter relative to distal shaft portion 68 to facilitate engagement and disengagement of distal shaft portion 68 from routing seal 46b. Chamber connector 70b can be formed as a groove on fluid displacer 36. The groove can extend fully annularly about the reciprocation axis RA.

Chamber connector 70b radially overlapping with routing seal 46b disconnects displacer 36 from routing seal 46b. Chamber connector 70b radially overlapping with routing seal 46b fluidly connects flow chamber 32b and transfer chamber 34b.

In some examples, central shaft portion 66 and proximal shaft portion 64 can have the same diameter. In some examples, central shaft portion 66a and proximal shaft portion 64 can have different diameters. In some examples, central shaft portion 66 and distal shaft portion 68 can have the same diameter. In additional or alternative examples, distal shaft portion 68 and proximal shaft portion 64 can have the same diameter. In some examples, the diameter of the distal shaft portion 68 can vary from one or both of the diameter of the central shaft portion 66 and the proximal shaft portion 64.

Transfer pathways 20a, 20b extend between and fluidly connect the pumping chamber 14 of pump 12b with the routing fluid chambers of pump 12a. In the example shown, the transfer pathway 20a includes transfer passage 50a formed in fluid housing 54. The transfer pathway 20a further includes feed passage 80a formed in pump cap 52. In the example shown, the transfer pathway 20b includes transfer passage 50b formed in fluid housing 54. The transfer pathway 20b further includes feed passage 80b formed in pump cap 52. In the example shown, the transfer pathway 20a is unobstructed between transfer chamber 34a and pumping chamber 14 of pump 12b. In the example shown, the transfer pathway 20b is unobstructed between transfer chamber 34b and pumping chamber 14 of pump 12b.

Pump cap 52 at least partially defines pumping chamber 14 in the example shown. Pump cap 52 is at least partially disposed within assembly body 30. In the example shown, pump cap 52 is at least partially disposed within a cap receiver 76 disposed at an end of a displacer bore 38. In the example shown, pump cap 52 is retained within fluid housing 54 by end cap 56b. Pump cap 52 can be considered to be clamped between end cap 56b fluid housing 54, while being at least partially disposed within fluid housing 54. Clamping pump cap 52 to fluid housing 54 facilitates quick and easy access to and removal of the multiple pump caps 52, such as for servicing and replacement. The end cap 56b can hold each of the pump caps 52 on fluid housing 54, such that each pump cap 52 can be clamped and unclamped simultaneously. It is understood, however, that pump cap 52 can be connected to fluid housing 54 in any desired manner, such as by fasteners among other options.

Pump cap 52 defines portions of the flowpath of the pumped fluid through assembly body 30. In the example shown, the pump cap 52 at least partially defines the transfer pathways 20a, 20b between pump 12a and pump 12b. Pump cap 52 includes chamber bore 78 and feed passages 80a, 80b. Chamber bore 78 at least partially defines the pumping chamber 14. Chamber bore 78 is open through the exterior of pump cap 52. In the example shown, chamber bore 78 is open through top side 82 of pump cap 52.

Feed passage 80a intersects with chamber bore 78. Feed passage 80a is fluidly connected to chamber bore 78. Feed passage 80a extends between an exterior of pump cap 52 and chamber bore 78. Feed passage 80a is open through top side 82 in the example shown.

Feed passage 80b intersects with chamber bore 78. Feed passage 80b is fluidly connected to chamber bore 78. Feed passage 80b extends between an exterior of pump cap 52 and chamber bore 78. Feed passage 80b is open through top side 82 in the example shown.

The feed passages 80a, 80b are fluidly separated from each other. Feed passage 80a and feed passage 80b open on the exterior of pump cap 52 at different locations on the exterior of pump cap 52. The port of feed passage 80a open through the exterior of pump cap 52 is aligned with an opening into transfer passage 50a such that feed passage 80a is in direct fluid communication with transfer passage 50a. The port of feed passage 80b open through the exterior of pump cap 52 is aligned with an opening into transfer passage 50b such that feed passage 80b is in direct fluid communication with transfer passage 50b. Fluid flowing between pumping chamber 14 and transfer passage 50a flows through feed passage 80a. Fluid flowing between pumping chamber 14 and transfer passage 50b flows through feed passage 80b.

FIGS. 5A-5F illustrate a pump cycle of pump 12b, which is discussed in more detail. It is understood that the pump cycle of pump 12b is descriptive of the pumping by each of the pumps 12 of the multi -piston assembly 10 and can be applied to any of the multiple pumps 12. A pump cycle includes fluid displacer 34 moving through a first stroke in a first axial direction ADI along the reciprocation axis RA and the fluid displacer 34 moving through a second stroke in a second axial direction AD2 along the reciprocation axis. The first stroke can also be referred to as an upstroke, fill stroke, or suction stroke. The second stroke can also be referred to as a discharge stroke, downstroke, or pressure stroke. The pump 12 is configured to intake fluid during the first stoke and output fluid during the second stroke in the example shown.

Pump 12a provides active checking for pump 12b to route fluid to pumping chamber 14 of pump 12b and route fluid from pumping chamber 14 of pump 12b. The fluid displacer 34 of pump 12a both pumps fluid through the pumping chamber 14 of pump 12a and routes the fluid to and from pump 12b in the example shown. Similarly, and as discussed above, the fluid displacer 34 of pump 12b both pumps fluid through pumping chamber 14 of pump 12b and routes fluid to and from pump 12c; the fluid displacer 34 of pump 12c both pumps fluid through the pumping chamber 14 of pump 12c and routes fluid to and from pump 12d; the fluid displacer 34 of pump 12d both pumps fluid through the pumping chamber 14 of pump 12d and routes fluid to and from pump 12a.

The fluid displacer 34 of pump 12a can be considered to form valving for pump 12b and a fluid mover for pump 12a. As such, the fluid displacer 34 of each pump 12 both routes fluid to another pump 12 of multi-displacer assembly 10 and pumps fluid.

For purposes of discussion, pump pathway 28a is assumed to be configured as the inlet pathway 22 through which fluid is provided to pumps 12 and pump pathway 28b is assumed to be configured as the outlet pathway 24 through which fluid is output from pumps 12. Transfer chamber 34a can be considered to form the inlet chamber 16 and transfer chamber 34b can be considered to form the outlet chamber 18.

During operation, the drive 26 is rotated on drive axis DA. Drive 26 outputs linear motion to fluid displacers 36 to cause pumping by the pumps 12. In FIG. 5 A, the fluid displacer 36 of pump 12b is changing over from a pressure stroke to a fill stroke. The fluid displacer 36 of pump 12b is at the bottom of a stroke in axial direction AD2 and changing direction to begin a stroke in axial direction ADI. Proximal shaft portion 64 of the fluid displacer 36 of pump 12a is engaged with routing seal 46a such that pumping chamber 14 of pump 12b is fluidly disconnected from the inflow through pump pathway 28a. As such, the inlet valve to pump 12b is in a closed state. Distal shaft portion 68 of the fluid displacer 36 of pump 12a is engaged with routing seal 46b such that pumping chamber 14 of pump 12b is fluidly disconnected from the outflow through pump pathway 28b. As such, the outlet valve to pump 12b is in a closed state. Fluid displacer 34 of pump 12a engaging with routing seal 46a fluidly isolates flow chamber 32a from transfer chamber 34a. Fluid displacer 34 of pump 12a engaging with routing seal 46b fluidly isolates flow chamber 32b from transfer chamber 34b. In FIG. 5B, fluid displacer 34 of pump 12a has moved in first axial direction ADI from the position shown in FIG. 5 A and partially through the fill stroke. The fluid displacer 36 of pump 12b has changed over and begun moving through a fill stroke in axial direction ADI. The proximal shaft portion 64 of the fluid displacer 36 of pump 12a disengages from routing seal 46a. The fluid displacer 36 of pump 12a moves such that chamber connector 70a radially overlaps with routing seal 46a, opening a flowpath between fluid displacer 36 of pump 12a and routing seal 46a of pump 12a. Chamber connector 70a overlapping with routing seal 46a disconnects displacer 36 from routing seal 46a to open the flowpath. As such, the inlet valve of pump 12b is actuated to an open state. Flow chamber 32a is fluidly connected to transfer chamber 34a. The fluid can fill into pumping chamber 14 of pump 12b as displacer 36 of pump 12b moves through the fill stroke. The fluid flows from pump pathway 28a to flow chamber 32a, from flow chamber 32a to transfer chamber 34a through the inlet valve formed between fluid displacer 36 of pump 12a and routing seal 46a, through transfer passage 50a, through feed passage 80a, and into pumping chamber 14 of pump 12b.

Central shaft portion 66 maintains contact with chamber seal 48 to fluidly separate transfer chamber 34a and flow chamber 32b within displacer bore 38. With multi- displacer assembly 10 in the state shown in FIG. 5B, the transfer chambers 34a, 34b are fluidly connected via the transfer passages 50a, 50b, feed passages 80a, 80b, and pumping chamber 14, but are not directly fluidly connected together within displacer bore 38. The fluid is required to flow through the transfer pathway 20a, through pumping chamber 14, and through transfer pathway 20b to move from transfer chamber 34a to transfer chamber 34b.

Distal shaft portion 68 maintains contact with routing seal 46b to fluidly separate transfer chamber 34b and flow chamber 32b. As such, the outlet valve of pump 12b is maintained in a closed state. Distal shaft portion 68 of the fluid displacer 36 of pump 12a further maintains contact with displacer seal 44b to fluidly separate the pumping chamber 14 of pump 12a from the routing pathways associated with pump 12b.

In FIG. 5C, the fluid displacer 36 of pump 12a has continued to move through the fill stroke for pump 12a and has reached a top of the fill stroke for pump 12a. The fluid displacer 36 of pump 12b continues to move through the fill stroke for pump 12b. Pump pathway 28a remains fluidly connected to pumping chamber 14 of pump 12b and pump pathway 28b remains fluidly disconnected from the pumping chamber 14 of pump 12b. The fluid displacer 36 of pump 12a reverses direction and begins to move in axial direction AD2 and through a pressure stroke for pump 12a. The fluid displacer 36 of pump 12b continues to move in direction ADI and through the fill stroke. The fluid can continue to fill into pumping chamber 14 through transfer chamber 34a and transfer pathway 20a until the fluid displacer 36 of pump 12a reengages with routing seal 46a.

In FIG. 5D, the fluid displacer 36 of pump 12a is reengaged with routing seal 46a. The inlet valve for pump 12b has closed and the fluid displacer 36 of pump 12b is at the top of a fill stroke. The fluid displacer 36 of pump 12b is changing over from a fill stroke to a pressure stroke. The pumping chamber 14 of pump 12b is fluidly disconnected from both pump pathways 28a, 28b. The pumping chamber 14 of pump 12b is fluidly disconnected from both the inflow and the outflow of multi-displacer assembly 10.

In FIG. 5E, the fluid displacer 36 of pump 12a is moving through a pressure stroke and the fluid displacer 36 of pump 12b has changed over and begun moving through a pressure stroke in axial direction ADI. The distal shaft portion 68 of the fluid displacer 36 of pump 12a disengages from routing seal 46b. The fluid displacer 36 of pump 12a moves such that chamber connector 70b radially overlaps with routing seal 46b, opening a flowpath between fluid displacer 36 of pump 12a and routing seal 46b of pump 12a. Chamber connector 70b overlaps with routing seal 46b to disconnect displacer 36 from routing seal 46b to open the flowpath. As such, the outlet valve of pump 12b is actuated to an open state. Flow chamber 32b is fluidly connected to transfer chamber 34b. The fluid can be displaced from pumping chamber 14 of pump 12b as the displacer 36 of pump 12b moves through the pressure stroke. The fluid flows from pumping chamber 14 of pump 12b, through feed passage 80b and transfer passage 50b to transfer chamber 34b, from transfer chamber 34b to flow chamber 32b through the outlet valve formed between fluid displacer 36 and routing seal 46b, and to pump pathway 28b to be output from multidisplacer assembly 10.

In FIG. 5F, the fluid displacer 36 of pump 12a has continued to move through the pressure stroke for pump 12a and has reached the bottom of the pressure stroke for pump 12a. The fluid displacer 36 of pump 12b continues to move through the pressure stroke for pump 12b as the outlet valve for pump 12b is maintained in an open state. Pump pathway 28b remains fluidly connected to pumping chamber 14 of pump 12b and pump pathway 28a remains fluidly disconnected from the pumping chamber 14 of pump 12b. The fluid displacer 36 of pump 12a reverses direction and begins to move in axial direction ADI and through a fill stroke for pump 12a. The fluid displacer 36 of pump 12b continues to move in axial direction ADI and through the pressure stroke. The fluid can continue to be displaced out of pumping chamber 14 of pump 12b through transfer pathway 20b and transfer chamber 34b and out to flow chamber 32b until the fluid displacer 36 of pump 12a reengages with routing seal 46a.

In FIG. 5G, the fluid displacer 36 of pump 12a is moving to reengage with routing seal 46b. The outlet valve for pump 12b is closing and the fluid displacer 36 of pump 12b is approaching the bottom of a pressure stroke. The pumping chamber 14 of pump 12b remains fluidly connected to pump pathway 28b until distal shaft portion 68 reengages with routing seal 46b.

The multi-displacer assembly shifts to the state shown in FIG. 5A from the state shown in FIG. 5G. Both the inlet and outlet valves of pump 12b are closed and the pumping chamber 14 of pump 12b is fluidly disconnected from both pump pathways 28a, 28b. The fluid displacer 36 of pump 12b has reached the end of the pressure stroke and is turning over to the begin a fill stroke. Pump 12b has thus completed a full pump cycle and can continue being driven through additional pump cycles to provide continuous pumping. Pump 12a continues to be driven through reciprocation cycles to provide active checking for pump 12b.

In the example shown, the inflow of fluid to pump 12b flows in axial direction AD2 within the displacer bore 38 of pump 12a. The fluid flows in axial direction AD2 from flow chamber 32a to transfer chamber 34a. The outflow of fluid from pump 12b flows in axial direction ADI within the displacer bore 38 of pump 12a. The fluid flows in axial direction ADI from transfer chamber 34b to flow chamber 32b. As such, the inflow and outflow from pump 12b are routed in opposite axial directions within the displacer bore 38 of the pump 12a providing checking for pump 12b. The two flows are axially towards each other in the example shown, though it is understood that the two flows are axially away from each other in examples in which flow is reversed. Multi-displacer assembly 10 provides significant advantages. The fluid displacers 36 of each pump 12 both provide active checking to another one of the pumps 12 of the multi-displacer assembly 10 as well as to pump fluid through multi-displacer assembly 10. The fluid displacers 36 providing active checking for others of the pumps 12 reduces part count by eliminating check valves that were previously required to check fluid flow to and/or from the pumping chambers 14. The fluid displacers 36 of multi-displacer assembly 10 are sequenced such that at least one of the pumps 12 of multi-displacer assembly 10 is outputting fluid flow throughout operation. Multi-displacer assembly 10 thereby provides a continuous outflow. The multi-displacer assembly 10 provides even, smooth outflow, which is particularly advantageous for applying fluid at steady outflow rate. For example, multi-displacer assembly 10 can be utilized for outputting a bead of material at a desired size, such as a bead of adhesive.

It is understood that although a four fluid displacer 34, 90-degree phased multi-displacer assembly 10 is shown, other numbers of fluid displacers 36 and their corresponding phasing are possible. Multi-displacer pumping assembly 10 can include any desired number of multiple fluid displacers 36. In some examples, multi-displacer assembly 10 is configured with pumps 12 in a multiple of four, such as four fluid displacers 36, eight fluid displacers 36, twelve fluid displacers 36, etc. It is understood that increasing the number of pumps 12 and corresponding fluid displacers 36 can provide for a smoother and more even fluid output. Such changes in number of fluid displacers 36 and the phasing between the pumps 12 may require changes to the relative locations of the pump pathways 28a, 28b and/or the lengths of the fluid displacer 34 that allow fluid movement or similarly block fluid movement.

Multi-displacer assembly 10 provides for first in-first out flow through the pumps 12. The pumps 12 do not include a common chamber through which fluid flows both to and from pumping chamber 14. In multi-displacer assembly 10, the transfer chambers 34a, 34b are not directly fluidly connected but are instead connected by discrete flowpaths that extend between the pumping chamber 14 and one transfer chamber 34a, 34b. Transfer chambers 34a, 34b are fluidly separated from each other within the common displacer bore 38 within which those transfer chambers 34a, 34b are formed. Transfer pathways 20a, 20b are fluidly separated from each other and combine only in pumping chamber 14. Transfer passages 50a, 50b are fluidly separated from each other.

During pumping operation, the fluid flows from transfer chamber 34a, through transfer pathway 20a, and into pumping chamber 14. Material remains within transfer pathway 20b and transfer chamber 34b up to the closed outlet valve. The feed pressure into multi-displacer assembly 10, in examples in which the inflow is pressurized, can further maintain the material already in transfer pathway 20b and transfer chamber 34b in transfer pathway 20b and transfer chamber 34b. The fluid displacer 36 changes over to a pressure stroke. The fluid displacer 36 increases the pressure in pumping chamber 14 to drive material out of pumping chamber 14. The pressure in pumping chamber 14 pressurizes the blocked pathway through transfer pathway 20a and transfer chamber 34a such that fluid does not flow upstream. The outlet valve is open and the fluid is driven downstream from pumping chamber 14 through transfer pathway 20b, transfer chamber 34b, and out to pump pathway 28b. Transfer chamber 34a and transfer chamber 34b are not fluidly connected other than through a pumping chamber 14 of an adjacent pump 12. The transfer chambers 34a, 34b not being directly fluidly connected encourages the first in-first out flow, which prevents residency of the fluid and can prevent pack-out and clogging.

In the example shown, transfer chamber 34b has a smaller volume than transfer chamber 34a. Such a configuration can further facilitate one-way, first in-first out flow for multi-displacer assembly 10. Such a configuration can inhibit residual fluid in the downstream transfer chamber 34b while also encouraging a quick rise in pressure after the displacer 36 of pump 12b changes over and begins a pressure stroke.

In the example shown, the flowpaths downstream of the pumping chamber 14 (e.g., transfer pathway 20b and transfer chamber 20b) have a smaller volume than the flowpaths upstream of pumping chamber 14 (e.g., transfer chamber 20a and transfer pathway 20a). Such a configuration can inhibit residual fluid in the downstream transfer chamber 34b while also encouraging a quick rise in pressure after the displacer 36 of pump 12b changes over and begins a pressure stroke.

Multi-displacer assembly 10 facilitates first in-first out flow without requiring the use of additional valves. The fluid displacers 36 can provide the only valving for flow of fluid through a pump 12 between the pump pathways 28a, 28b. Removal of additional valving reduces part count and simplifies assembly and manufacturing. Fluid housing 54 can be formed as a monolithic component in which various pathways are machined. Fluid housing 54 being formed as a monolithic component also simplifies manufacturing and can reduce costs.

Fluid displacer 36 provides active checking for another pump 12. Fluid displacer 36 is configured to move into and out of engagement with routing seal 46a to open and close the inlet valve for an adjacent pump 12. Fluid displacer 36 is configured to move into and out of engagement with routing seal 46b to open and close the outlet valve for the adjacent pump 12. Fluid displacer 36 maintains the transfer chambers 34a, 34b as fluidly separated within the displacer bore 38 such that fluid does not flow directly between transfer chambers 34a, 34b. The multiple chamber connectors 70a, 70b of fluid displacer 36 facilitate the separately formed inlet and outlet valves that have different seats (e.g., routing seals 46a, 46b) disposed at different axial locations along reciprocation axis RA. Maintaining fluid separation between transfer chambers 34a, 34b assists in first in-first out flow, preventing pack out and residual fluid, among other deleterious effects.

FIG. 6A is an isometric view of pump cap 52. FIG. 6B is a cross-sectional view taken along line B-B in FIG. 6A. FIGS. 6A and 6B are discussed together with continued reference to FIGS. 1-5G. Pump cap 52 includes cap body 84, chamber bore 78, feed passages 80a, 80b and seal groove 86. Cap body 84 includes top side 82, bottom side 88, and body side 90. Feed passage 80a, 80b respectively extend between outer openings 94a, 94b and inner openings 96a, 96b.

Pump cap 52 is configured to at least partially define a pumping chamber 14 of a pump 12. Pump cap 52 is mountable to assembly body 30, such as by being clamped to fluid housing 54. Fluid passages of pump cap 52 are formed in cap body 84. Seal groove 86 extends into an exterior of cap body 84. Seal groove 86 extends into body side 90 of cap body 84. Seal groove 86 is configured to receive a fluid seal (e.g., an elastomer seal such as an o-ring). The fluid seal seals between seal groove 86 and fluid housing. In the example shown, the cap body 84 is elongate between longitudinal ends 92. The seal groove extends about the elongate cap body 84 such that seal groove 86 is non-circular about the reciprocation axis RA.

In the example shown, the cap body 84 includes two lateral sides 91 that extend between the longitudinal ends 92. The lateral sides converge towards each other. The lateral width of cap body 84 reduces between the two longitudinal ends 92. Such a configuration provides mistake proofing during installation of pump cap 52, ensuring alignment of chamber bore 78 on the reciprocation axis RA, alignment of feed passage 80a with transfer passage 50a, and alignment of feed passage 80b with transfer passage 50b.

Bottom side 88 is configured to be oriented outward away from the pumping chamber 14. Top side 82 is configured to be oriented axially inward and towards the drive 26. Chamber bore 78 is formed in cap body 84. Chamber bore 78 can at least partially define the pumping chamber 14. Chamber bore 78 extends partially through cap body 84. Chamber bore 78 can be aligned on pump axis PA. Chamber bore 78 can be configured as a cylindrical bore within cap body 84. Chamber bore 78 is open through top side 82 of cap body 84.

Feed passages 80a, 80b are open through the side of chamber bore 78. Feed passages 80a, 80b are fluidly connected to chamber bore 78. Feed passage 80a extends between an outer opening 94a and inner opening 96a. Feed passage 80b extends between an outer opening 94b and an inner opening 96b.

Outer openings 94a, 94b are open through the exterior of cap body 84. Outer openings 94a, 94b provide ports for fluid to enter into or exit from the feed passages 80a, 80b. Outer openings 94a, 94b provide ports for fluid to enter into or exit from the cap body 84. Outer opening 94a is spaced from outer opening 94b on the exterior of cap body 84. Outer opening 94a does not overlap with outer opening 94b. Outer openings 94a, 94b are open through the same side of cap body 84 as chamber bore 78 in the example shown. Outer openings 94a, 94b are open through the top side 82 of cap body 84 in the example shown.

Inner openings 96a, 96b are open through the side of chamber bore 78. In the example shown, the inner openings 96a, 96b are formed through a radial side of chamber bore 78. Inner openings 96a, 96b provide ports for fluid to flow between feed passages 80a, 80b and pumping chamber 14. In the example shown, inner openings 96a, 96b are spaced from each other on the wall of chamber bore 78. The inner opening 96a does not overlap with the inner opening 96b. As such, feed passages 80a, 80b are maintained fluidly separated.

Aperture 98 extends into cap body 84. In the example shown, aperture 98 extends into bottom side 88 of cap body 84. Aperture 98 is configured to receive a tool to facilitate dismounting of pump cap 52 from fluid housing 54. For example, the tool can be inserted into aperture 98 to connect to aperture 98 and exert a pulling force in axial direction AD2 to pull the cap body 84 out of cap receiver 76. In some examples, aperture 98 can be threaded and the tool can be formed as or include a threaded post (e.g., a bolt).

Pump cap 52 provides significant advantages. In the example shown, the flowpaths for the pumped fluid are maintained fluidly separated at all locations between the inlet and outlet valves of the pump except for in the pumping chamber 14. Such a configuration minimizes common flow area and prevents residency of fluid while encouraging first-in first-out flow. Feed passages 80a, 80b maintain the fluid flows fluidly isolated except for in pumping chamber 14.

While the invention(s) has been described with reference to an exemplary embodiment(s), it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention(s) without departing from the essential scope thereof. Therefore, it is intended that the invention(s) not be limited to the particular embodiment(s) disclosed, but that the invention(s) may include all embodiments falling within the scope of the appended claims. Any single feature, or any combination of features from one embodiment show herein, may be utilized in a different embodiment independent from the other features shown in the embodiment herein.

Accordingly, the scope of the invention(s) and any claims thereto are not limited to the particular to the embodiments and/or combinations of the features shown herein, but rather can include any combination of one, two, or more features shown herein.

Claims

CLAIMS:

1. A multi-displacer assembly comprising: an assembly body; a first assembly passage extending within the assembly body; a second assembly passage extending within the assembly body; a first fluid displacer configured to reciprocate along a first pump axis within a first displacer bore to pump fluid through a first pumping chamber; and a second fluid displacer configured to reciprocate along a second pump axis within a second displacer bore, the second displacer bore including a first transfer chamber and a second transfer chamber, wherein the first transfer chamber and the second transfer chamber are fluidly connected to the first pumping chamber, and wherein the second fluid displacer fluidly separates the first transfer chamber from the second transfer chamber within the second displacer bore; wherein the second fluid displacer is configured to reciprocate along the second pump axis through: an inlet open state in which the first assembly passage is fluidly connected to the first transfer chamber and the second transfer chamber is fluidly disconnected from the second assembly passage by the second fluid displacer, a closed state in which the first transfer chamber is fluidly disconnected from the first assembly passage and the second transfer chamber is fluidly disconnected from the second assembly passage; and an outlet open state in which the first transfer chamber is fluidly disconnected from the first assembly passage and the second transfer chamber is fluidly connected with the second assembly passage.

2. The multi-displacer assembly of claim 1 , further comprising: a first routing seal disposed within the second displacer bore, the second fluid displacer disengaged from the first routing seal in the inlet open state and engaged with the first routing seal in the closed state and the outlet open state.

3. The multi-displacer assembly of claim 2, further comprising: a second routing seal disposed within the second displacer bore, the second fluid displacer disengaged from the second routing seal in the outlet open state and engaged with the second routing seal in the closed state and the inlet open state.

4. The multi-displacer assembly of any one of claims 1-3, wherein the second fluid displacer includes: a first chamber connector configured to at least partially define an inlet flowpath between the first assembly passage and the first transfer chamber with the second fluid displacer in the inlet open state.

5. The multi-displacer assembly of claim 4, wherein the first chamber connector is formed as a groove.

6. The multi-displacer assembly of claim 5, wherein the groove extends fully annularly about the second reciprocation axis.

7. The multi-displacer assembly of any one of claims 4-6, wherein the second fluid displacer includes: a second chamber connector configured to at least partially define an outlet flowpath between the second assembly passage and the second transfer chamber with the second fluid displacer in the outlet open state.

8. The multi-displacer assembly of claim 7, wherein the second chamber connector is formed as a second groove.

9. The multi-displacer assembly of claim 8, wherein the second groove extends fully annularly about the second reciprocation axis.

10. The multi-displacer assembly of any one of claims 7-9, wherein the second fluid displacer includes: a central shaft portion disposed axially between the first chamber connector and the second chamber connector, the central shaft portion engaging a chamber seal disposed within the second displacer bore, the central shaft portion maintaining sealing contact with the chamber seal throughout reciprocation of the second displacer.

11. The multi-displacer assembly of claim 10, wherein the second fluid displacer has a larger diameter at the central shaft portion than at the first chamber connector and at the second chamber connector.

12. The multi-displacer assembly of claim 10, wherein the second fluid displacer has a first diameter at the central shaft portion, a second diameter at the first chamber connector, and a third diameter at the second chamber connector, and wherein the first diameter is larger than the second diameter and larger than the third diameter.

13. The multi-displacer assembly of claim 12, wherein the second diameter is the same as the third diameter.

14. The multi-displacer assembly of any one of claims 10-13, wherein the central shaft portion at least partially defines a second flow chamber within the second displacer bore, the second flow chamber continuously fluidly connected to the second assembly passage.

15. The multi-displacer assembly of any one of claims 10-14, wherein the second fluid displacer further comprises: a proximal shaft portion disposed on an opposite axial side of the first chamber connector from the central shaft portion, the proximal shaft portion engaging an upper displacer seal disposed within the second displacer bore, the proximal shaft portion maintaining sealing contact with the upper displacer seal throughout reciprocation of the second displacer.

16. The multi-displacer assembly of claim 15, wherein the proximal shaft portion at least partially defines a first flow chamber within the second displacer bore, the first flow chamber continuously fluidly connected to the first assembly passage.

17. The multi-displacer assembly of claim 16, wherein a diameter of the proximal shaft portion is the same as a diameter of the central shaft portion.

18. The multi-displacer assembly of any one of claims 16 and 17, wherein a diameter of the proximal shaft portion is greater than a diameter of the first chamber connector and a diameter of the second chamber connector.

19. The multi-displacer assembly of any one of claims 15-18, wherein the proximal shaft portion is configured to move into and out of sealing engagement with an upper routing seal disposed within the second displacer bore to open and close flow between the first assembly passage and the first transfer chamber.

20. The multi-displacer assembly of any one of claims 10-19, wherein the second fluid displacer further comprises: a distal shaft portion disposed on an opposite axial side of the second chamber connector from the central shaft portion, the distal shaft portion engaging a lower displacer seal disposed within the second displacer bore, the distal shaft portion maintaining sealing contact with the lower displacer seal throughout reciprocation of the second displacer.

21. The multi-displacer assembly of claim 20, wherein a diameter of the distal shaft portion is the same as a diameter of the central shaft portion.

22. The multi-displacer assembly of any one of claims 20 and 21, wherein a diameter of the distal shaft portion is the same as a diameter of the proximal shaft portion.

23. The multi-displacer assembly of any one of claims 20-22, wherein a diameter of the distal shaft portion is greater than a diameter of the first chamber connector and a diameter of the second chamber connector.

24. The multi-displacer assembly of any one of claims 19-23, wherein the distal shaft portion is configured to move into and out of sealing engagement with a lower routing seal disposed within the second displacer bore to open and close flow between the second assembly passage and the second transfer chamber.

25. The multi-displacer assembly of any one of claims 1-24, wherein the second displacer is configured to pump the fluid through a second pumping chamber by reciprocation along the second reciprocation axis.

26. The multi-displacer assembly of claim 25, wherein the second pumping chamber is disposed coaxially with the first transfer chamber and the second transfer chamber.

27. The multi -displacer assembly of any one of claims 1-26, further comprising: a drive connected to the first displacer to drive the first displacer through a pressure stroke and the drive connected to the second displacer to drive the second displacer through a downstroke, the drive configured to convert a rotational input to a linear output to move the first displacer and the second displacer.

28. The multi -displacer assembly of claim 27, wherein the drive is connected to the first displacer to move the first displacer through both the pressure stroke and a fill stroke.

29. The multi-displacer assembly of any one of claims 27 and 28, wherein the drive is connected to the second displacer to move the second displacer through both the downstroke and an upstroke.

30. The multi-displacer assembly of any one of claims 27-29, wherein the drive is configured as a wobble drive.

31. The multi-displacer assembly of any one of claims 27-30, wherein the drive includes an eccentric and a plate, the plate configured to provide the linear output to the first fluid displacer and the second fluid displacer.

32. The multi-displacer assembly of claim 31 , wherein the plate is formed as a ring including a plurality of posts.

33. The multi-displacer assembly of claim 1 , further comprising: a first routing seal disposed within the second displacer bore, the first routing seal disposed axially between the first transfer chamber and a first flow chamber fluidly connected to the first assembly passage; a second routing seal disposed within the second displacer bore, the second routing seal disposed axially between the second transfer chamber and a second flow chamber fluidly connected to the second assembly passage; and a chamber seal disposed within the second displacer bore and disposed axially between the first transfer chamber and the second transfer chamber.

34. The multi-displacer assembly of claim 33, wherein the second displacer includes: a proximal shaft portion configured to engage with the first routing seal to fluidly disconnect the first transfer chamber from the first assembly passage; a distal shaft portion spaced axially along the second reciprocation axis from the proximal shaft portion, the distal shaft portion configured to engage with the second routing seal to fluidly disconnect the second transfer chamber from the second assembly passage; and a central shaft portion disposed axially between the proximal shaft portion and the distal shaft portion, the central shaft portion engaging the chamber seal throughout reciprocation of the second displacer.

35. The multi-displacer assembly of claim 34, wherein the second displacer further comprises: a first chamber connector disposed axially between the proximal shaft portion and the central shaft portion, the first chamber connector radially overlapping with the first routing seal to fluidly connect the first assembly passage and the first transfer chamber.

36. The multi-displacer assembly of claim 35, wherein the second displacer further comprises: a second chamber connector disposed axially between the distal shaft portion and the central shaft portion, the second chamber connector radially overlapping with the second routing seal to fluidly connect the second assembly passage and the second transfer chamber.

37. The multi-displacer assembly of any one of claims 1-36, further comprising: a pump cap at least partially defining the first pump chamber, the pump cap fluidly connected to the first transfer passage and the second transfer passage.

38. The multi-displacer assembly of claim 37, wherein the pump cap includes: a first chamber bore at least partially defining the first pumping chamber; a first feed passage extending between a first outer port on an exterior of the pump cap and the first chamber bore, the first feed passage disposed fluidly between the first transfer passage and the first pumping chamber; and a second feed passage extending between a second outer port on the exterior of the pump cap and the first chamber bore, the second feed passage disposed fluidly between the second transfer passage and the first pumping chamber.

39. The multi-displacer assembly of claim 38, wherein the first outer port is spaced from the second outer port.

40. The multi-displacer assembly of claim 38, wherein the first outer port does not overlap with the second outer port.

41. The multi-displacer assembly of any one of claims 38-40, wherein the first feed passage extends to a first inner port open to the first chamber bore, and the second feed passage extends to a second inner port open to the first chamber bore.

42. The multi-displacer assembly of claim 41, wherein the first inner port is spaced circumferentially about the first reciprocation axis from the second inner port.

43. The multi-displacer assembly of claim 41, wherein the first inner port does not overlap with the second inner port.

44. The multi-displacer assembly of any one of claims 38-43, wherein the first chamber bore is cylindrical.

45. The multi-displacer assembly of any one of claims 38-44, wherein the first chamber bore opens through a top side of the pump cap, the first outer port is formed on the top side, and the second outer port is formed on the top side.

46. The multi-displacer assembly of any one of claims 38-45, wherein a cap body of the pump cap is elongate.

47. The multi-displacer assembly of any one of claims 38-44, wherein a cap body of the pump cap includes a top side configured to be oriented in a first axial direction along the first reciprocation axis, and a bottom side opposite the top side, the first displacer configured to move through a fill stroke in the first axial direction.

48. The multi-displacer assembly of claim 47, wherein the cap body is elongate between a first longitudinal end and a second longitudinal end.

49. The multi-displacer assembly of any one of claims 47 and 48, wherein the first chamber bore, the first outer port, and the second outer port are formed through the top side.

50. The multi-displacer assembly of any one of claims 47-49, further comprising: an aperture extending into the bottom side of the cap body, the aperture configured to receive a tool for dismounting of the pump cap from the assembly body.

51. The multi-displacer assembly of claim 50, wherein the aperture is threaded.

52. The multi-displacer assembly of any one of claims 37-51, wherein the assembly body comprises: a fluid housing within which the first displacer bore and the second displacer bore are formed; a cap receiver axially overlapping with the first displacer bore and formed in the fluid housing, the pump cap at least partially disposed within the cap receiver to mount the pump cap to the assembly body.

53. The multi-displacer assembly of claim 52, wherein the fluid housing is formed as a monolithic block within which each of the first displacer bore, the second displacer bore, the first transfer passage, and the second transfer passage are formed.

54. The multi-displacer assembly of any one of claims 52 and 53, wherein the assembly body further comprises: a first end cap connected to the fluid housing, the first end cap retaining the pump cap within the cap receiver.

55. The multi-displacer assembly of claim 54, wherein the first end cap is connected to the fluid housing by a plurality of threaded fasteners.

56. The multi-displacer assembly of any one of claims 1—55, wherein a first transfer pathway between the first transfer chamber and the first pumping chamber is unobstructed.

57. The multi-displacer assembly of claim 56, wherein a second transfer pathway between the first pumping chamber and the second transfer chamber is unobstructed.

58. The multi-displacer assembly of any one of claims 1-57, wherein the first transfer chamber and the second transfer chamber are fluidly connected through the first pumping chamber such that fluid must flow through the first pumping chamber between the first transfer chamber and the second transfer chamber.

59. The multi-displacer assembly of any one of claims 1-57, wherein the first transfer chamber and the second transfer chamber are not fluidly connected other than through the first pumping chamber.

60. A multi-displacer assembly comprising: an assembly body; a first assembly passage extending within the assembly body; a second assembly passage extending within the assembly body; a first fluid displacer configured to reciprocate along a first reciprocation axis within a first displacer bore to pump fluid through a first pumping chamber; and a second fluid displacer configured to reciprocate along a second reciprocation axis within a second displacer bore, the second displacer bore including a first transfer chamber and a second transfer chamber, the first transfer chamber and the second transfer chamber are fluidly connected to the first pumping chamber, and the second fluid displacer fluidly separating the first transfer chamber from the second transfer chamber within the second displacer bore; wherein the second fluid displacer is configured to fluidly connect and disconnect the first assembly passage from the first transfer chamber, and the second fluid displacer is configured to fluidly connect and disconnect the second assembly passage from the second transfer chamber.

61. A multi-displacer assembly comprising: an assembly body; a first assembly passage extending within the assembly body; a second assembly passage extending within the assembly body; a plurality of fluid displacers, each fluid displacer of the plurality of fluid displacers configured to reciprocate on a respective reciprocation axis within a respective displacer bore in the assembly body; wherein each fluid displacer of the plurality of fluid displacers is configured to displace fluid from the first assembly passage to the second assembly passage, and each fluid displacer of the plurality of fluid displacers is configured as a checking displacer configured to actively check fluid flow into and out of a pumping chamber of an adjacent fluid displacer of the plurality of fluid displacers; wherein a pumping flowpath of the adjacent fluid displacer flows in a single direction from the first assembly passage, to a first transfer chamber disposed along the reciprocation axis of the checking fluid displacer, to the pumping chamber of the adjacent fluid displacer, to a second transfer chamber disposed along the reciprocation axis of the checking fluid displacer and spaced axially from the first transfer chamber, and then to the second assembly passage.

62. The multi-displacer assembly of claim 61 , wherein the first transfer chamber and the second transfer chamber are fluidly isolated other than through the pumping chamber of the adjacent fluid displacer throughout reciprocation of the checking fluid displacer.

63. The multi-displacer assembly of any one of claims 61 and 62, wherein the plurality of fluid displacers are reciprocated out of phase.

64. The multi-displacer assembly of any one of claims 61-63, wherein the plurality of fluid displacers includes four fluid displacers.

65. A displacer for a multi-displacer assembly, the displacer configured to provide active checking to a pumping displacer of the multi-displacer assembly, the displacer comprising: a proximal shaft portion extending along a reciprocation axis and having an upper diameter; a distal shaft portion extending along the reciprocation axis, spaced axially from the proximal shaft portion and having a lower diameter; a central shaft portion extending along the reciprocation axis, disposed axially between the proximal shaft portion and the distal shaft portion, and having a central diameter; a first chamber connector disposed axially between the proximal shaft portion and the central shaft portion, a diameter of the first chamber connector smaller than the upper diameter; and a second chamber connector disposed axially between the central shaft portion and the distal shaft portion, a diameter of the second chamber connector smaller than the lower diameter.

66. A pump comprising: the displacer of claim 65 at least partially disposed within a first displacer bore, the displacer configured to reciprocate along the reciprocation axis through a reciprocation cycle including an upstroke in a first axial direction along the reciprocation axis and a downstroke in a second axial direction along the reciprocation axis; a first displacer seal disposed in the first displacer bore, the proximal shaft portion engaging the first displacer seal through the reciprocation cycle; a second displacer seal disposed in the first displacer bore, the distal shaft portion engaging the second displacer seal throughout the reciprocation cycle; a chamber seal disposed in the first displacer bore axially between the first displacer seal and the second displacer seal, the central shaft portion engaging the chamber seal throughout the reciprocation cycle; a first routing seal disposed in the first displacer bore axially between the first displacer seal and the chamber seal, wherein the displacer is configured to move into and out of sealing engagement with the first routing seal to open and close a flowpath between the first routing seal and the displacer; and a second routing seal disposed in the first displacer bore axially between the second displacer seal and the chamber seal, wherein the displacer is configured to move into and out of sealing engagement with the second routing seal to open and close a flowpath between the second routing seal and the displacer.

67. A multi-displacer assembly comprising: the pump of claim 66; a pumping displacer configured to reciprocate within a second displacer bore to pump fluid through a pumping chamber; a first transfer pathway extending between and fluidly connecting a first transfer chamber in the first displacer bore and the pumping chamber; and a second transfer pathway extending between and fluidly connecting a second transfer chamber in the first displacer bore and the pumping chamber; wherein the first transfer chamber is at least partially defined by the first routing seal and the second transfer chamber is at least partially defined by the second routing seal; wherein the chamber seal is disposed axially between the first transfer chamber and the second transfer chamber; and wherein the first transfer pathway is fluidly isolated from the second transfer pathway except through the pumping chamber.

68. A pump cap for a pump of a multi-displacer assembly, the pump cap comprising: a cap body having a top side configured to be oriented in a first axial direction along an axis, and a bottom side opposite the top side; a chamber bore within the cap body and extending along the axis, the chamber bore at least partially defining a pumping chamber; a first feed passage extending between a first outer port on an exterior of the cap body and the chamber bore; and a second feed passage extending between a second outer port on the exterior of the pump cap and the chamber bore.

69. The pump cap of claim 68, wherein the first outer port is spaced from the second outer port.

70. The pump cap of claim 68, wherein the first outer port does not overlap with the second outer port.

71. The pump cap of any one of claims 68-70, wherein the first feed passage extends to a first inner port open to the chamber bore, and the second feed passage extends to a second inner port open to the chamber bore.

72. The pump cap of claim 71 , wherein the first inner port is spaced circumferentially about the axis from the second inner port.

73. The pump cap of claim 71 , wherein the first inner port does not overlap with the second inner port.

74. The pump cap of any one of claims 68-73, wherein the chamber bore is cylindrical.

75. The pump cap of any one of claims 58-74, wherein the chamber bore, the first outer port, and second outer port are formed on the top side.

76. The pump cap of claim 68, further comprising: a seal groove formed in the exterior of the cap body on a side of the cap body extending between the top side and the bottom side.

77. The pump cap of claim 76, wherein the seal groove is non-circular.