PT92514B - PUMP WITH SHIFT DEFINED - Google Patents

Abstract

A positive displacement pump comprises a variable volume pump chamber (16-1) and a drive mechanism (26-1) having a displacement member (25-1) for reducing the volume of the pump chamber(16-1). Fluid enters the pump chamber (16-1) from a supply chamber (15-1) located adjacent to and surrounding the lateral outer boundary of the pump chamber (15-1) through a valve-controlled inlet passage (17-1) that opens to the pump chamber (16-1) at an elongated gap-like inlet opening. The inlet passage permits fluid to flow from the supply chamber (15-1) into the pump chamber (16-1) with substantially no pressure drop.

Description

Most pumps with a well-defined displacement - that is, pumps that have a pumping chamber of varying volume that includes a mobile displacement element - admit and discharge the fluid through openings that open to the chamber through a wall non-moving camera. Inlet and outlet openings usually have one-way valves, such as spherical check valves or flap valves. Due to the limited space available for the openings and the fact that the limiting factor of the pumping capacity is usually in the incoming and outgoing pipes of the pump and not in the pump itself, the inlet and outlet openings are relatively small. The small dimensions of the openings limit the inlet and outlet flow rates, create pulsating inlet and outlet flows and consume energy in the form of dynamic fluid friction and losses due to turbulence. On the other hand, the relatively small dimensions of the inlet openings on most pumps require a relatively high pressure difference between the inlet and the pumping chamber to ensure filling during the vacuum ride.

inventor of the present invention has done considerable work for several years in the development of

- 9.

blood for the replacement or supplementation of the anatomical heart in pumping blood through the vascular system. There are several characteristics to which blood pumps must satisfy, which are not easily obtained. On the one hand, it is desirable that a mechanical blood pump be able to take blood substantially continuously, preferably with a minimum pulse rate. Second, a mechanical blood pump must be able to adjust its output automatically to variations in the inlet, in a reasonably wide range. Thirdly, a blood pump that includes valves must be as free as possible from dead spaces, spaces where the flow is small or nonexistent and where, therefore, blood can accumulate and form clots; blood must be kept moving through the entire pump and at any time. Fourth, a blood pump must be sterile and free of toxic materials when put into use and must remain so while in use .

More and more mechanical blood pumps are used for temporary use, for example during an open heart operation or to help a damaged heart for a short time while it heals. Artificial hearts with currently used mechanical pumps are only partially satisfying. the requirements mentioned. For example, they are not able to adjust automatically to changes in the body's blood needs, but instead have to be supervised and controlled very closely. Current systems of mechanical blood pumps require a relatively large amount of blood. of the patient flows out of the body, having to add an amount of blood equal to that which is outside the patient's body, which is undesirable.

X

-3 U.S. Patent No. 4,648,877 to Lundbáck (March 10, 1987) describes and represents a blood pump that very efficiently meets the requirements mentioned above. The pump according to said patent has a chamber (atrium) and a pumping chamber (ventricle) joined by a short passage containing a one-way valve. The chambers are made of a flexible material, substantially inextensible and can be made relatively inexpensively, so they can be replaced when used by different patients outside the body. An actuation ring is actuated in a way to reduce the volume of the pumping chamber, that is, for a good bar of blood from the pumping chamber, and is moved in the opposite direction to draw blood in response to the entry of blood from the chamber. feed. The design of the Lundbáck patent pump is such that there are no dead spaces where the blood flow is relatively stopped, and the blood can clump and form clots. While flow limitations are minimized, the pump has three relatively small openings, two of which have a one-way valve1,

Summary of the invention

An object of the present invention is to provide a pump with a well-defined displacement with small losses of hydraulic flow. Another object is to minimize the pressure drop through the inlet direction of the pump and thereby ensuring rapid flow to the chamber. pump, even with reduced differential pressure through the inlet to the pumping chamber. Subsidiary to the latter object and a minimization of

-4pulse in the flow upstream of the pump, either when the inlet is closed (back pressure) or when it is closed (induction pulse). In this regard, it is intended that the uni-directional valves capable of closing substantially reliable without having to be subjected and without causing a re-flow can be provided in order to avoid shocks from reflux. It is also intended to simplify and minimize the costs of replacing a pump, that is, all the ducts, chambers and valves through which the blood (or other fluid) flows and which, preferably, are not reused. another object is to provide a pump that automatically adjusts its outlet to the inlet and that requires a minimum amount of fluid inside the pump.

The foregoing objects, and others, are reached, according to the present invention, by a pump with a well-defined displacement, similar to the pump of the mentioned Lundbáck patent of invention, which includes a feeding chamber to receive the fluid to be pumped, a variable volume pumping, an inlet passage through which the fluid is conveyed from the supply chamber to the pumping chamber and an outlet through which the fluid is discharged. A displacement element associated with the pumping chamber is likely to move in opposite directions along a predetermined path, in order to move through a variable displacement zone of the pumping chamber to alternately increase and decrease the volume of the chamber. A drive mechanism moves the displacement element by at least one direction to decrease the volume of the pumping chamber. An inlet valve closes the inlet passage to block the

-5flow of fluid out of the pumping chamber through the inlet passage.

According to the present invention, the feed chamber is generally disposed laterally in relation to the displacement zone of the Pumping chamber and substantially involves that area, and the inlet passage has substantially the same extension as the feed chamber and opens to the pumping chamber through an opening in the form of an elongated gap in a limiting wall of the pumping chamber located laterally in relation to the displacement zone, so that the fluid can enter the pumping chamber through the inlet passage substantially without any pressure drop. Preferably, the pumping chamber includes a movable wall element to which the displacement element can be applied on the unloading path and the said moving wall element being freed from the displacement element during the suction path, that the volume of the pump is established by the flow of fluid inlet through the suction passage, It is usually advantageous to make the pumping chamber generally round (circular or oval), with a substantially larger diameter than the height.

According to another aspect of the present invention, a wall of the pumping chamber, perpendicular to the direction of movement of the displacement element, Ó is made of a flexible material and is actuated and flexed by the displacement element through the displacement zone to decrease the chamber volume. A suction passage network can also be made of a flexible material and, preferably, form a single piece with the transverse wall of the pumping chamber. A form of inlet valve includes a movable clamping valve element that applies and moves the flexible wall in the inlet passage through the inlet passage against the opposite wall, or with a flap valve, in order to close the opening . Alternatively, the inlet valve may be a flap of flexible material fixed at one of its edges to a port of the inlet passage and having its other edge free in such a way that it is sensitive to fluid flow and / or pressure opening in the suction chamber of the pumping chamber and closing in the pumping path by applying it to another wall of the passage or applying it to a similar flexible flap fixed on the other wall of the entrance passage.

In some embodiments, the pumping chamber has an outlet in the form of an opening and the outlet valve for the outlet opening uses the flexible pumping chamber and a movable valve element that moves the flexible wall against the outlet opening. exit, thus closing it. Other forms of valves, such as flap valves, can be used at the outlet of the pumping chamber. It is also possible to omit an outlet valve completely.

Advantageously, the feed chamber, the passage of passage and the pumping chamber are defined by two sheets of flexible material supported by rigid support elements such as those necessary to carry weights and lift forces due to pressure. The material sheets are drevely shaped to define the walls of the pumping chamber, the feed chamber and the inlet passage and are joined, in a fence,

-7 on its outer peripheries. The rigid support elements define the shapes with the maximum volumes of the chambers and the shape of the inlet opening for the pumping chamber.

The preferred annular and circular shapes of the pump chamber and the feed chamber provide deflections of the flexible wall of the pumping chamber with minimal wrinkling and provide uniformity of fluid flow radially into the pumping chamber. With an outlet arranged axially in opposition to the displacement element, uniform outflow is ensured radially and then axially. In the circular form, the flow through the pump takes place with reduced levels of turbulence, but at relatively high speeds, without dead zones.

The present invention also includes embodiments with a variable volume chamber on a second stage that receives fluid from the pumping chamber during the latter's discharge path. A portion of the fluid discharged from the pumping chamber during its discharge passage passes through the second floor chamber to a discharge passage, while the rest is conducted during the aspiration passage of the second floor chamber, which preferably works in opposition. phase with the pumping chamber. In this way, fluid is discharged from the pump in a substantially continuous manner, that is, during both the suction and the discharge paths, with pulsations in the discharge being reduced.

preferred camera element - pre-patterned sheets of flexible material joined in a sealing relationship in their sheriffs-series - can be produced at low cost and is easy to install in a support structure. It is therefore advantageous, economically and practically, that the chamber element is a disposable element.

For a better understanding of the present invention, reference is made to the description which will follow of embodiments given as examples, made in conjunction with the accompanying drawings.

Description of Drawings

In the attached drawings the figures represent:

Figs. IA to 7A, generic schematic views of seven forms of making single-stage pumps, represented in their configurations during the suction ride;

Figs. 1B to 7B, schematic cross-sectional views of the embodiments of the respective figures, IA to 7A, shown during their discharge routes;

Fig. 6C, a plan view of the chamber element of the embodiment of figs. 6A and 6B;

Fig. 7C, a schematic cross-sectional view of the embodiment of figs. 7A and 7B, at the end of the Asoira tion Dasseio;

Figs, 8A and 83, schematic cross-sectional views of a two-stage pump according to the present invention, in different stages of operation;

Figs. 9A and 9B, views similar to those of figs. 8A and 8B, showing a modified two-stage pump;

Figs. 10A and 10B, schematic cross-sectional views of yet another embodiment of a two-stage pump according to the present invention, in different phases of its operation, corresponding to the phases shown in figs. 8A, 9A and 8B, 9B, respectively; and

Fig. 10C, a plan view of the chamber element of the embodiment of figs. 10A and 10B.

The corresponding parts of all embodiments are designated by the same reference numbers, followed by a hyphen and a number after the hyphen corresponding to the figure number, which makes the complete reference number different for each particular embodiment. .

Description of the embodiments

In all the embodiments represented in the drawings, the surfaces that are contacted by the liquid being pumped are the internal surfaces of a disposable, discoid, generally circular or partially circular chamber element, which has a file and an outlet and which is made of a flexible, but substantially inextensible material, such as polyethylene, polyurethane or other plastic film. In other embodiments, not shown, some or all of these surfaces may, however, be surfaces of pump elements. fixed or movable metal, for example, which are permanent parts of the pump. On the other hand, the chamber element does not have to be circular.

As shown in FIGS, IA and 18, the pump has a housing comprising a fixed base element (10-1) and an upper element (11-1) removable or articulated in a hinge. The element of discoid chambers is designated (12-1) and is interposed between the base element and the uppermost element. At its periphery, the chamber element (12-1) has an inlet connection (13-1) and , at its center, an axial and raised outlet union (14-1), element (12-1) has an annular feed chamber (15-1) into which the entrance union (13-1) opens. Inside the feed chamber there is a pumping chamber (16-1) which communicates along its boundary side wall portion with the feed chamber (15-1) via an inlet passage (17-1) under the in the form of an endless opening in the form of an annular gap between the opposite walls of the element. The pumping chamber (16-1) communicates with the central outlet union (14-1) via a wing. outlet (18-1) which is also formed in an endless angel gap.

element (12-1) can be made of any reliable material with the appropriate characteristics necessary for the specific use of the pump in each particular case. Naturally, the material must be compatible with the liquid to be pumped and sufficiently flexible, durable and difficult to extend to withstand the pressure and mechanical stresses, as well as, if applicable, the thermal applied to it, lower element (10 -1) of the housing supports several mobile components on which the element (12-1) rests and which pumping by its repetitive and cyclic movements, these with components comprise a centrally positioned outlet valve element (20-1), which it serves to open and close the outlet passage (18-1) to allow the flow between the pumping chamber (16-1) and the outlet union (14-1]. The outlet valve element is movable vertically 1 parallel to the central axis of the pump (21-1) so that, in its upward movement, it opens the opposite walls of the element against the upper element (11-1) of the housing, thus closing the outlet passage (18-1 ), and so that in its downward movement it permits prevent the element's walls from moving apart, thereby opening the exit path. The movements of the outlet valve element (2Q-1) are derived from a lever (22-1) which, in turn, is actuated by a cam, or another suitable actuating element (not resentable) and a blown motor ^ of.

There is also an inlet clamping element (23-1) which works in a manner analogous to the outgoing clamping element (22-1] to open and close the inlet passage (17-1), the element of inlet valve (23-1) Õ annular, and its movements - upward and downward are derived from a wing vanca (24-1) which, in turn, is acted in synchronism with the.value wing (22-1 } with meat ((not shown) driven by a motor.

-12 Between the valve elements (20-1) and (23-1) and opposite the pumping chamber (16-1), an annular displacement element (25-1) is provided which is vertically displaced upwards and downwards by means of a lever (26-1) and a meat (not resentable) driven by a motor, in a similar way to that of the valve elements and in synchronism with them. The displacement element (25-1) serves to positively move the lower wall of the pump chamber in its upward movement, thereby reducing the volume of the pumping chamber (16-1) and, in its downward movement, allowing that the pumping chamber expands while the fluid flows into the pumping chamber.

In the embodiments of Fig. IA and 1B there are also two rollers (27-1) placed underneath the supply chamber (15-1) of the element (12-1). When the pump is running, these rollers , which may be more than two, are led to describe a circular orbit along the feeding chamber, by means not shown, Dara keep the liquid inside the feeding chamber in constant motion. Such agitation of the liquid may be necessary or advantageous in certain applications, for example when the liquid is blood.

When the pump is running, the supply chamber (15-1) acts as a reservoir, the volume of which varies according to the inlet flow and which continuously receives liquid, at a relatively low pressure, through the connection or union of entrance (13-1). In the phase of the pumping cycle shown in fig. IA, in which the inlet passage (17-1) is open and the displacement element (25-1) is moving downwards or has pre-precisely reached its lowest position, liquid flows from the supply (15-1) to the pumping chamber (16-1) through the inlet passage (17-1). The filling of the pumping chamber can be done very quickly, because the inlet passage is very long, that is, it has a very large peripheral extension and can be easily opened at a relatively substantial height. In other words, the inlet passage can be easily opened to provide a very large cross-sectional area for the flow. On the other hand, due to the fact that the supply chamber and inlet flow involve most or all of the periphery of the pumping chamber and the fluid enters radially from all directions, the filling length, that is, the distance that the liquid has to run Dara fill the pumping chamber, it is short and straight, so that the flow into the pumping chamber can take place very quickly and substantially without pressure drop. Pumps with annular chambers may have large caoacjidades and, however, have short filling times, due to the large area of the entrance passage and the short filling path.

filling of the pumping chamber (15-1) and is substantially passive - it occurs essentially only under the action of the hydrostatic pressure that exists in the supply chamber (15-1) in the inlet passage ( 17-1), Dorque inside the Bombaqem chamber does not produce any suction as a direct sequence of the downward movement of the displacement element (25-1); the displacement element has no force transmission connection with the element (12-1) that is efficient in the direction of the expansion of the pumping chamber (from top to bottom).

It is within the objectives of the present invention to exert a certain influence on the filling, causing the pressure inside a mass of gasses surrounding the pumping chamber to vary in a particular way during the pumping cycle. It is also possible to exert influence on the filling by subjecting the inlet or the supply chamber to external pressure.

As shown in Fig. 1B, the entry passage (17-1) is then closed by an upward movement of the input element (23-1), and the exit passage (13-1) is opened by a downward movement of the valve element (20-1). Then, the displacement element (25-1) is moved upwards to displace the bottom wall of the pumping chamber Dara upwards and thereby to expel the liquid in the pumping chamber (16-1) through the outlet passage (18- 1) and the outlet union (14-1). In the meantime, the feed chamber (15-1) is refilled from the inlet fitting (13-1). The exit passage (18-1) is then closed, the displacement element (25-1) is retracted downwards and the entrance passage (17-1) is opened again so that another cycle can be carried out. pumping.

A characteristic of the described pump resides in the combination of the annular inlet passage (17-1), the annular outlet passage (18-1) and the short filling path, which allows a very fast filling of the pumping chamber, even when the ness on the inlet side is very low, and very quick emptying of the pumping chamber. The Dortanto pump can pump a large volume of liquid per unit of time with small internal losses and therefore with a very high efficiency. While the

-15 inlet flow for the pump does not exceed the flow rate that corresponds to the product of the maximum flow volume by the flow rate, the pump, due to its self-regulation, adapts the pumped volume for each flow to the inlet flow. Within a relatively wide range of inlet flows through the inlet fitting (13-1), therefore, the pump adapts to the continuous inlet flow, free from pressure pulses and interruptions. If the inlet flow has to exceed the flow rate corresponding to the aforementioned product, the pump speed or rate of travel may be increased. Due to reduced internal losses, the rate of tours can rise to high levels.

Another characteristic that is present in the described pump, as well as in the pumps that will be described, and that contributes to the quick filling of the pumping chamber (16-1), lies in the fact that it provides a sufficiently large volumetric capacity of the supply (15-1) - preferably substantially larger than that of the pumping chamber (16-1) - to ensure filling of the pumping chamber (16-1) without requiring any substantial refilling of the supply chamber (15- 1) when filling the pumping chamber. Thus, all the liquid entering the pumping chamber (16-1) during the filling phase of the pumping cycle is immediately available near the inlet passage (17-1) when the filling phase begins.

element (12-1) is arranged in the pump housing or housing (10-1 / 11-1) in such a way that the feed chamber (15-1) can expand and contract freely between limits

-16, depending, respectively, on the liquid inlet flow to the supply chamber and the outlet flow from the supply chamber to the Pumping chamber (16-1).

The embodiment of fig. 2A and 2B differs from that of figs.

IA and 1B just because the rollers (27-1) are omitted and the feed chamber £ 15-2] is opened to the atmosphere. Thus, the pressure at which the pumping chamber is filled (16-2) is determined by the difference in level between the inlet passage (17-2) and the free surface of the liquid in the supply chamber,

In the embodiment of figs. 3A and 3B, the feed chamber (15-3) is open, as in figs. 2A and 2B. One-way or lip-type check or hinge valves (23-3) and £ 20-3] are provided, respectively in the inlet passage £ 17-3] and in the outlet passage (18-3). Consequently, the movable pinch valve elements in the two first embodiments are replaced by portions of the housing element (10-3) that support the chamber element and define passages (17-3) and (18-3), Each of the valves (23-3) and (20-3) is formed by two annular flaps axially opposed of flexible material (for example, plastic), which can also be slightly elastic, whose outer edges are fixed in a sealing way (by for example, by heat sealing) on the walls of the respective opposite elements in the entrance passage (17-3) and that Dodem can deform freely and can thus move up and down on their inner edges.

When Dara liquid is passing in the entrance or exit passage, the oalas are kept away

-17 without appreciably resisting the flow of liquid, but as soon as there is a tendency for the liquid to flow in the opposite direction, the flaps close the passage to block the flow. Although the flaps are elastic, their elasticity is not so great that they cannot reliably withstand the pressures that occur and there is therefore no danger of turning in the wrong direction. When the operating pressure of the pump is high, the flaps can be reinforced with an appropriate material, such as glass fibers, to prevent their inversion.

The flaps can be designed in such a way that they contribute, by virtue of their elasticity, to the initial shape, or otherwise, to accelerate the flow of the liquid, when they are open. In addition, they may be slightly polarized with a tendency to open or closed position.

In a modified embodiment, which is not shown, one of the valves or both can combine a pinch valve of the type shown in figs. 1 and 2 with a visor. In this case, the squeeze valve is referenced disoosta to close the associated passage only incompletely, leaving the complete closure for a flap.

As shown in figs, 3A and 3B, the flap valves with hinge are formed by an oala element separate from the walls of the chamber element. However, the flaps can advantageously also be formed by a fold in the sheet or film material. that the element is made, with the formation of this fold taking place during the manufacture of the chamber element.

-18-, mentioned lastly, lends itself to production by means of known techniques- for the manufacture of elements and other plastic objects (vacuum molding and blow molding). The same design can also be adopted in the embodiments described below.

The embodiment shown in figs. 4A and 4B is similar to that of figs. IA and 1B, except that the outlet valve is in the form of a check valve or unidirectional valve (20-4) of the type of flap or wool, arranged in the outlet union (14-4), and that the displacement (25-4) is disk or plate (mushroom). In this case, the pumping chamber (16-4) has, in plan view, the shape of a disc, instead of being annular as in the previous embodiments. On the other hand, the outlet passage (18-4) (fig. 4B) is formed only near the end of the pumping path, which corresponds to a shape and function somewhat different from the previous embodiments.

The embodiment shown in figs. 5A and 5B differs from that of figs. 4A and 4B because the rollers have been omitted for the agitation of the liquid in the feed chamber (15-5), as the inlet valve (23-5) comprises a single ring of flexible material that is connected along its outer edge to the lower wall of the element and capable of moving. Dose a Dosage at ρ 1 i_ each in a watertight way to the upper wall of the element under the action of pressure inside the pumping chamber (16-5) and by means of the vtl it in the inlet duct is omitted.

-19 It has been found that, in certain cases, a valve that closes to block backflow in the outlet duct is not necessary, particularly when the pump operates with a high frequency of sidewalks. In such cases, the amount of movement of the outgoing liquid stream is sufficient to allow the pumping chamber (16-5) to be filled through the inlet passage (17-5), even if the pumping chamber is open on the exit during aspiration.

Figs. 6Α and 68 show an embodiment that is similar to Figs. 5A and 5B, except with regard to Dosing and the design of the outlet passage (18-6), the outlet union (14- 6) and the associated outlet valve (20-6).

The outlet joint (14-6) and in this case radial and is positioned diametrically opposite the inlet joint (13-6), therefore, has its upstream end on the periphery of the pumping chamber (16-6) and , like the inlet joint (13-6), extends radially outward. Therefore, a portion, but only a portion, of the periphery of the element is not used for the feed chamber (15-6) and for the inlet passage (17-6), but the latter can still be very long.

In this embodiment, the outlet valve (20-6) is a flap or lobe similar to the inlet valve (26-3) and, like the latter, is attached to an outlet Dassage Dart (18-6) that it is located at the junction between the pumping chamber (16-6) and the supply chamber (15-6) see fig, 6C, which is a plan view of the chamber element (12-6).

-20Can be advantageous in the embodiment shown in figs. 6A, 65 and 6C Block or close the feed chamber area (15-6) adjacent to the outlet union. The feed chamber network must then be shaped so that no pockets are formed in which the liquid being Bombado estagne or is forced to undergo abrupt changes in direction in its flow to reach the outlet passage.

The outlet connection (14-6) of the embodiment of fig.

6A, 6B and 6C do not necessarily have to be aligned with the inlet joint, but can form a smaller or larger angle with the inlet joint. If desired, the two joints can even be placed side by side and substantially parallel. However, it is essential that the inlet passage (17-6) and its valve extend over the largest portion of the periphery of the chamber. bombaem.

Figs. 7A, 7B and 7C represent an embodiment in which a part of the annular feed chamber (15-7) is located closer to the center of the element than the inlet passage (17-7) in the form of an elongated gap. , the drive mechanism of the displacement element (25-7) is a threaded shaft mechanism with ball support - not resent in detail - whose threaded shaft has a connection, fixed in rotation, with the rotor (28-7) of an electric motor mounted on the lower element (10-7) of the pump housing.

As is evident from the comparison of figs. 7A, 7B and 7C with each other, the movement of the displacement element (25-7) of this embodiment has a direct influence on the shape and volume of the feeding chamber. So, when the displacement element moves downwards (falls), see fig. 7A, the chamber volume of a 1 i. decrease, because the displacement element causes the supply chamber to collapse, see fig. 7C. The liquid in the supply chamber then flows into the pumping chamber (16-7) together with the liquid entering the pump. through the input union (13-7). When the displacement element is activated upwards, thus reducing the volume of the pumping chamber, see fig, 7B, the supply chamber is enlarged and, at the same time, the inlet valve is closed (23-7) The liquid which then enters the inlet port is accommodated in the feed chamber and then, when the downward movement of the displacement element follows, flows into the pumping chamber, as described.

The embodiment shown in figs. 7A, 7B and 7C also have an outlet valve (20-7) which prevents backflow into the pumping chamber (16-7) from the outlet union (14-7). As shown in the figures, the exit union is parallel and is positioned diametrically opposite the entrance union, although it may be possible to face other orientations and positions,

The outlet valve (20-7) is an annular flap valve, one of the peripheral edges of the flap being fixed on the upper element (11-7) of the pump housing and the other free nerfic edge provided with an annular bead (29 -7). This annular rim reinforces the edge of the flap and, in the closed position of the valve (fig. 7C), it is tightly applied to the inner dart of the upper element (11-7) of the housing. As an alternative to conception

-22 illustrated from the outlet valve, a vertically polarized movable valve element can be pro-cycled by a spring, which seals against an annular portion of the wall at the point where the pumping chamber joins with the horizontal outlet union,

The inlet valve (23-7) of the embodiment shown in figs. 7A, 7B and 7C is also an annular hinge valve, which is attached to the displacement element, thus moving with it. This arrangement results in a favorable flow pattern of the liquid that flows from the feed chamber into the pumping chamber, but it is within the scope of the Dresente invention to fix the visor on the pump housing and arrange things so that their mobile portion cooperates with the displacement element.

As in the other described embodiments in which the inlet valve is a wool or flap valve, the inlet passage (17-7) opens to allow flow into the pumping chamber with a small pressure drop as soon as the pressure upstream of the valve only slightly exceeds the pressure on the downstream side. Similarly, the inlet port closes immediately when the pressure in the pumping chamber only slightly exceeds the pressure on the upstream side of the valve. The rapid opening and closing of the flap valves Dodem can be attributed to the annular configuration and the large area of the surface resulting from the valve on which the pressure acts. For the same reason, the outlet valve (20-7) and, consequently, the outlet passage (18-7), closes immediately when the pressure in the outlet union (14-7) exceeds the pressure in the pumping chamber at the beginning of the suction path.

-23As fig. 8A and 8B represent a pump in which there are two displacement elements (25-8A) and (25-8B) which operate in phase opposition to reduce the volumes of different sections of the pumping chamber at different times.

A displacement element (25-3A) resembles the displacement element shown in figs. 4 to 8 and serves to reduce the volume of a central section of the second floor of the chamber (Ί6-8Α), which is similar to the pumping chamber of figs. 4 to 6 and communicates with a central outlet union (14-3).

another displacement element (25-8B) is annular and concentric with the central element mentioned first, This outer annular element serves to reduce the volume of an external annular section (16-88) of variable volume of the pumping chamber, which and concentric with the central section (16-8A) of the variable volume stage sequence.

On its inner side radially, the outer section (18-38) of the pumping chamber communicates with the central section (Ί 8-3A) of the second floor of the chamber through an annular passage (30-8), in which a one-way flap valve (31-8) ^ which is similar to the flap valve of figs. 3 and 5 for opening to allow flow to the section (Ί6-8Α) of the pumping chamber. This passage constitutes either an inlet port for the central section (16-8A) of the pumping chamber or an outlet port for the outer section (16-8B) of the pumping chamber,

-24On its radially outer side, the outer section (16-8B) of the pumping chamber communicates with an annular feed chamber (15-8), which is s-emel Fiante to the feed chamber of figs.

and 3, through an annular inlet passage (17-8) which has a one-way flap valve (23-8) that opens to allow flow to the portion (16-8BJ outside the pumping chamber and which also resembles the flap valve (23-3) and (23-5) of figures 3 and 5.

The two displacement elements (25-8A) and (25-8B) are actuated substantially in phase opposition by the mechanisms that resemble the mechanisms used to actuate the displacement element and the clamping valve of fig. 4. The maximum volumes of the sections of the pumping chamber and the movements of the two displacement elements are chosen in such a way that the volume of the sidewalk of the outer section (15-8B) of the pumping chamber is approximately equal to twice the the central section (16-8A) of the pumping chamber.

Fig. 8A represents a phase of the pump operating cycle in which the outer displacement element (25-8B) is moving downwards and the outer section (15-83) of the pumping chamber is filling up from the feeding chamber (15-8) through the inlet passage (17-8) without any appreciable pressure loss in it, while the central displacement element of the second floor (25-8A) is moving upwards or outwards the liquid from the central section (16-8A) of the second floor of the chamber, the hinge valve (31-8) being kept in the closed condition by pressure in the central section of the chamber,

-25In the phase shown in Fig. 88, the situation is reversed. Therefore, the outer displacement element (25-85) is moving upwards to expel liquid from the outer section (16-8B) of the pumping chamber, to the central section (16-8A) of the second floor of the chamber through the passage (30-8), while the central displacement element (25-8A) is moving downwards, allowing the central section of the chamber (16-8A) to expand under pressure that the liquid exerts on its walls, the volume of liquid expelled from the outer section of the pumping chamber during the upward movement of the outer displacement element is greater than the increase in volume of the central section of the second floor of the chamber. Consequently, liquid will be discharged through the outlet fitting (14-8) also at this stage (fig. 35) of the pump's operating cycle. While the inlet flow to the pumping chamber only occurs at the stage when the outer section of the pumping chamber is expanding, the discharge of the pump is substantially continuous, albeit with some displacement.

The embodiment shown in Figs, 9A and 95 has a similar structure and operation similar to the embodiment in Figs, 8A and 8B, with the exception that the mechanism is externally activated to act positively on the inner displacement element (25-9A) in the upward direction will be replaced by an adjustable spring mechanism (26-9A), which constantly requests this element of displacement upwards, during the country. upward sinus of the outer displacement element (25-9A), the central displacement element of the second floor (25-9A) is displaced

-26 downwards under the action of fluid pressure inside the central section (16-9A) of the second floor of the chamber, in order to compress the spring mechanism (26-9A), as shown in fig, 9A, Dl During the downward movement of the outer displacement element (26-9B), the energy stored in the spring mechanism displaces the central displacement element upward, as shown in figure 9A.

Figs. 10A and 10B are cross-sectional views corresponding to fig. 8A, 8B and 9A, 9B of another embodiment of a two-stage pump according to the present invention, and fig. 10C is a plan view of the chamber element of this other embodiment.

The pump shown in figs. 10A, 108 and 10C comprises two displacement elements (25-10A) and (25-10B) which function as described with reference to figs, 9A and 9B. Therefore, the displacement element (25-10B) is associated with a mechanis. actuating hand activated externally to act positively, or substantially positive, in the upward direction, while the displacement element (25-10A) is associated with an adjustable spring mechanism (26-1QA) that constantly pushes it upwards .

The two displacement elements (25-10A) and (25-105) and the associated pump chamber sections (18-10A) and (16-10B) of the chamber element (12-10) are offset horizontally from each other , and the inlet valve (23-10) and the valve (31-10) and] the sections of the pumping chamber are flap valves if

-27. · »Similar to the valves (23-6) and (20-5) of figs, 6A, 6B and 6C, In addition, as shown in fig, 10C, the inlet fitting (13-10) and the exit joint (14-10) are arranged side by side and substantially parallel,

Except for the different flow pattern, resulting from the horizontally offset arrangement of the chamber sections, the pump of figs, 10A, 10B and 10C works in substantially the same way as the pump of figs, 9A and 9B,

In the embodiments illustrated and described by way of example, the pumping chamber (15) and the supply chamber (15) of the chamber element are circular or have the configuration of a circular ring and as easily understood, the mechanical components of the pump have a corresponding shape. This form is normally preferred, taking into account aspects of both fluid flow and manufacture, but it is included in the scope of the present invention that the pump has a different configuration, for example more or less oval or with an alon configuration different. An elongated configuration can be envisaged especially in the case shown in Figs, 6A, 6B and 5C, where the inlet and outlet are aligned.

Furthermore, in the embodiments shown in figs. 8A, 8B and in figs. 9A, 9B, the central displacement elements (25-8A) and (25-9A) can be annular, like the outer elements (25-8B) and (25-9B), the open space within the displacement element central ring can then accommodate elements of the pump drive mechanism, for example, or be used

-28for other purposes. If, in that case, the drive mechanism is designed for the two displacement elements (25-8A) and (25-8B) of figs. 8A and 8B, in such a way that the elements can be acted in synchronism, with a chosen offset (for example in phase opposition or in the push-pul1J mode, or individually (only in one of the parts and acted), as desired, interesting sizes are offered to vary the characteristics of the pump in relation to the volume of the ride and the outflow,

In some cases, such as when using the pump as a blood pump, the displacement element can be connected in an appropriate way with the pumping mechanism in such a way that a certain elastic yielding of the displacement element with respect to the displacement mechanism is possible. pumping under the action of pressure in the pumping chamber, so that there is a certain delay of the displacement element during the pressure or discharge ride, the movement of the displacement element that is initially lost as a result of the delay is recovered at the end of the pressure control and can be used to ensure that the liquid does not become stagnant in the pumping chamber, for example under the valve (31-8) of the valve of figs, 8A and 8B. Such a provision can also be used to suppress any Dressão waves that tend to develop at the end of the discharge tour.

A pump of the type of figs, 3A and 88, with two or more displacement elements and sections of the pumping chamber, which Õ preferably annular, is also usable as a two-stage compressor (multi-stage), in particular for large amounts of air at relatively low pressure.

-29 characteristic of compressors built in this way is that only a single valve is required between the stages; each valve functions either as an outlet valve for an outer or lower stage radially and as an inlet valve for an inner or upper stage radially. The other forms of reali. are also usable as compressors or pumps (air or other gases), but it is thought that in practice they are better adapted to be used as liquid pumps,

As is evident from the drawings, a characteristic of the pump according to the present invention is that the liquid being pumped has a favorable flow pattern, because it can pass through the pump without sudden changes of direction that are imposed on it. Particularly advantageous in this regard are the embodiments of figs. 1-6 and 8-10, in which the height of the pumping chamber is very small compared to the diameter, therefore the liquid is drained substantially horizontally up to the outlet union, The generally low or flat shape of the pumping chamber also allows a small walk in length, which means that the frequency of walks can be high. In conjunction with the large cross-sectional area for the flow that the inlet and outlet passages can have, this feature guarantees a very low internal resistance of the pump.

In the embodiments of fig. 5-10, the use of single-wing valves that are attached to the lower wall of the el? chambers (12) and which are liable to move upwards in the direction of the movement of the liquid

-30 displacement, to a position that is watertight against the upper mesh, and advantageous in that the flow of the fluid produced by the displacement element sweeps the underside of the flaps. This sweeping flow minimizes the danger of any potions of the fluid being pumped to stagnate under or behind the valve flaps. Therefore, those forms of reelization are particularly suitable for pumping blood, because they satisfy the very important requirement for blood pumps to be free from stagnant zones,

In the embodiments that have been exemplified in the drawings, the displacement element and its actuation mechanism are located under the pump chamber. This positioning is preferred in most cases, especially when, as in the illustrated embodiments, an easily replaceable element of chambers of oiled film or oil sheet provides the surfaces with which the fluid being treated pump contacts during its passage through the pump. However, in some cases, it may be advantageous that the displacement element forms the upper wall, or acts on the upper wall of the pumping chamber, and that the drive mechanism is placed above the pumping chamber. In addition, it is conceivable to have a common drive mechanism for two good opposing bases stacked on top of each other and operating in phase opposition. It is also possible to have two drive mechanisms for a single pumping chamber, one drive mechanism on each side, operating in opposition.

The chamber (16-10A) and the polarized displacement element

-31 with a spring (25-10A) of the embodiment of figs, 1 OA., 10B and 1OC can be used in conjunction with the outlets of single-stage pumps of other designs as a one-way valve and as a device to dampen the outlet pump pulsatoria, In the case of blood pumps, such a device provides a unidirectional outlet valve without stagnation zones and a volume with little stiffness downstream of the valve,

Claims (34)

Claim and s 1.- Improvement in a well-defined displacement pump that includes means that define a feeding chamber to receive the fluid to be pumped, means that define a pumping chamber of variable volume, an inlet passage through which the fluid is guided from the chamber supply to the pumping chamber, an outlet through which the fluid is discharged from the pumping chamber, a displacement element associated with the pumping chamber and movable in the opposite direction along a predetermined path in order to move through a variable displacement zone of the pumping chamber to alternately increase and decrease the volume of the chamber, actuating means to move the displacement element in at least one direction to decrease the volume of the pumping chamber, and valve means of inlet to close the inlet passage to block the backflow of fluid out of the pumping chamber through the inlet passage, c characterized by the feed chamber being generally arranged laterally and substantially involving -33 the displacement zone of the pumping chamber and because the inlet passage is substantially the same length as the feed chamber and opens into the pumping chamber through an elongated gap opening in a boundary wall of the pumping chamber It is generally located next to the displacement zone, so that fluid can enter the pumping chamber through the inlet passage substantially without any pressure drop. 2.- Improvement according to claim 1, characterized in that the pumping chamber includes a movable wall element to which the displacement element can be applied in the discharge path or can not be applied during the suction path in a way that the pump ride volume is established by the fluid pressure in the supply chamber. 3. - Improvement according to claim 1, characterized in that the pumping chamber is generally round. 4. Improvement according to claim 3, characterized in that the dimensions of the pumping chamber perpendicular to the direction of movement of the displacement element are substantially larger than the dimensions in said direction of movement. 5.- Improvement in accordance with claim 3, -34 characterized in that the outlet is placed substantially in the center of a fixed transverse wall of the pumping chamber opposite the displacement element. 6. - Improvement according to claim 1, characterized in that the feed chamber is adapted to receive a continuous inlet flow of the fluid being pumped and to discharge at least a portion of its contents into the pumping chamber through of the inlet passage when the inlet valve means is open while collecting a fluid reservoir when the inlet valve means is closed. 7. Improvement according to claim 2, characterized in that the moving wall element of the pumping chamber is formed by a flexible material and is deformed and displaced by the displacement element during at least a portion of the pump discharge path. 8. Improvement according to claim 7, characterized in that the movable wall element forms a part of the boundary wall laterally of the pumping chamber and defines a wall of the inlet passage, and in that the valve means include a valve element of squeeze applied to said laterally movable boundary part of the wall in order to move said part of the boundary wall through the gap-shaped opening and thereby close the inlet passage, and actuating means to periodically move the element tightening valve through the opening. 9. Improvement according to claim 3, characterized in that the inlet valve means include a substantially annular flap of flexible material fixed along one of the edges to a wall of the inlet passage and having its other free edge to move to an open position to allow fluid inlet flow into the pumping chamber and to a closed position leaning against another passage wall ce pn + -t-? riA to stop the flow of fluid from the pumping chamber through the passage input. 10. Improvement according to claim 3, characterized in that the inlet valve means include a first annular flap of flexible material fixed along one edge to a wall of the inlet passage and a second annular flap of flexible material fixed along one edge to another wall of the inlet passage, the two flaps having their other free edges to allow movement to an open position to allow the flow of fluid inward into the pumping chamber and to a position closed against each other to stop the reflux of. pumping chamber fluid -36 through the entrance passage. 11.- Improvement according to claim 2, characterized in that the supply chamber and the pumping chamber are defined by a first and a second wall elements apart, at least one of these wall elements formed by a flexible material and including a first portion that can be contacted and displaced by the displaceable member to vary the volume of the pumping chamber and a second portion that defines a wall of the inlet passage. 12. An enhancement according to claim 11, characterized in that the valve means include a pinch valve element that is applied to said second portion of said first wall element and is mounted so as to move towards khan and to there through the inlet passage to close the latter and actuating means to cyclically move the clamping valve element through the inlet passage. 13.- Improvement according to claim 12, characterized in that the actuating means move the clamping valve element only partly through the inlet passage and furthermore comprise a flexible hinge valve strip fixed on the other wall of the passage entry and having a movable freeboard to apply to another portion or -37 second portion of said wall element in response to fluid pressure in the pumping chamber. 14.- Improvement according to claim 11, characterized in that the limit side wall of the pumping chamber is generally round and the feed chamber is generally annular and completely surrounds the pumping chamber. 15.- Improvement according to claim 11, characterized in that both the supply chamber and the pumping chamber are annular and in that the outlet of the pumping chamber is an annular opening located in an internal limit of the pumping chamber in general laterally in relation to the displacement zone. 16. Improvement according to claim 15, characterized in that it further comprises an outlet valve that includes a movable valve element which is applied to a third portion of the flexible wall element and actuating means for moving the valve element in reciprocating movement to displace said third portion of the flexible wall element by touching it and disengaging it from the opposite edge of the outlet opening to close and open it. 17.- Improvement according to claim 11, characterized in that the flexible wall element of the pump is the t -38- (lower element and further comprising means for supporting a fourth portion of the flexible wall element that forms the lower wall of the feed chamber. 18. Improvement according to claim 17, characterized in that the means for supporting the fourth portion of the flexible wall element includes one or more rollers and means for rotating the rollers in an orbital path along the feed chamber to continuously stir the fluid in the feed chamber. 19. Improvement according to claim 17, characterized in that the means for supporting the fourth portion of the flexible wall element is a rigid fixed element. 20. Improvement according to claim 15, characterized in that it further comprises a fixed element that is applied to a third portion of the flexible wall element in order to define an edge of the outlet opening, and at least one annular flap of material flexible fixed along one of its edges on one edge of the outlet opening and having its other edge free so that the flap moves in response to fluid flows in the outlet opening between positions that open and close the outlet opening. -3921. Improvement according to claim 11, characterized in that the other wall element defining the supply chamber and the pumping chamber is substantially immobile and the outlet of the pumping chamber is an opening in said other wall element. 22. Improvement according to claim 21, characterized in that there is an outlet valve means in the outlet opening. 23. An improvement according to claim 21, characterized in that the immobile wall element of the pumping chamber includes a sheet of flexible material joined in a sealing relationship to the first wall element along the outer periphery of the supply chamber and an element substantially rigid support which applies and supports the flexible sheet against deformation and deflection in response to the development of fluid pressure in the pumping chamber. 24.- Improvement according to claim 1, characterized in that it also comprises a variable volume chamber of a second stage in communication with the outlet of the pumping chamber so that it receives the fluid discharged from the pumping chamber, a unidirectional valve in the pumping chamber outlet to block fluid backflow from the second floor chamber -40 for a pumping chamber, a discharge passage leading from the second-stage chamber, a movable second-stage displacement element to alternately increase and decrease the volume of the second-stage chamber, and actuating means for moving the displacement element second floor in at least one direction to decrease the volume of the second floor chamber. 25. Improvement according to claim 24, characterized in that the driving means include an external energy source. 26. An enhancement according to claim 24, characterized in that the actuating means for the second stage displacement element are a spring that stores energy when the volume of the second stage chamber is increased by the flow of fluid from the chamber pump and releases stored energy when there is no inlet flow from the pumping chamber to the second floor chamber. 27.- Improvement according to claim 24, characterized in that the volume of the pumping chamber ride is about twice the volume of the second floor chamber ride. 28.- Improvement according to claim 26, -41 characterized in that the pumping chamber is substantially annular and the second floor chamber is substantially round and is generally located next to and surrounded by the pumping chamber. 29. - Improvement according to claim 28, characterized in that the pumping chamber and the second floor chamber are defined by a movable wall element of flexible material that can be contacted and displaced by the displacement element and the displacement element from the second floor on the respective discharge paths. 30. Improvement according to claim 28, characterized in that the outlet of the pumping chamber is a passage in the form of an annular gap at the junction between the pumping chamber and the second floor chamber. 31. Improvement according to claim 30, characterized in that the valve means at the outlet are an annular hinge valve of flexible material with one edge fixed to a wall of the outlet passage and the other free edge to respond to the flow of the fluid and to the pressure conditions in the chambers touching and disengaging from another wall of the outlet passage. 42. An improvement according to claim 24, characterized in that the feed chamber is substantially annular, the pumping chamber is substantially round, the outlet is a passage which is generally conducted laterally in relation to the pumping chamber and the second floor chamber is substantially round and is laterally disposed in relation to and close to the pumping chamber. 33. Improvement according to claim 1, characterized in that the pumping chamber is generally round, the supply chamber is generally annular, the supply chamber and the pumping chamber and the inlet passage are defined by a first element and a second element, both of a flexible material, joined at the outer periphery of the feed chamber in a sealing relationship, each of the flexible elements being permanently molded to define opposite walls of the respective chambers and the entrance passage, through one of the flexible elements have an outlet opening in their portion that defines the pumping chamber and further comprise rigid support elements that support the flexible elements against displacement under the action of the weight and pressure of the fluid in the pump. 34. - Improvement according to claim 33, characterized in that the inlet valve means include at least -43 less a substantially annular flap of flexible material joined along one edge to one of the flexible elements adjacent to the inlet passage and the other having its free edge, so that the ring leaves the inlet passage open in the absence of fluid reflux from inside the pumping chamber and deflect to close the inlet passage in response to reflux of fluid from the pumping chamber. 35. Improvement according to any one of claims 1 to 34, characterized in that the volumetric capacity of the supply chamber is at least as large as that of the pumping chamber. 36.- Chamber element for a well-defined displacement pump, characterized by comprising a first and a second sheet of flexible material joined at its peripheries in a sealing relationship and permanently molded to define a generally annular feeding chamber, a generally round pumping chamber inside the supply chamber and an inlet passage that forms an elongated gap opening at the junction of the supply chamber with the pumping chamber, an outlet opening in a wall of the pump chamber and an opening at least one wall of the feed chamber. A chamber element according to claim 36 / characterized in that the inlet valve is a flap valve with an annular flap of flexible material joined along one of its edges to one of the leaves adjacent to the inlet passage and having its other edge free, so that the flap leaves the inlet passage open in the absence of reflux of the fluid from the inside of the pumping chamber and flexes to close the inlet passage in response to the reflux of the fluid coming from the inside of the pumping chamber.