WO2020055849A1

WO2020055849A1 - Multi-outlet pressure vessel, system, and method for wet abrasive blasting

Info

Publication number: WO2020055849A1
Application number: PCT/US2019/050389
Authority: WO
Inventors: Nicholas K. STUDT; Bryce J. GAPINSKI; Niles M. HICKMAN; Alexander J. DAEGER; Patrick W. ACKERMAN
Original assignee: Graco Minnesota Inc
Current assignee: Graco Minnesota Inc
Priority date: 2018-09-10
Filing date: 2019-09-10
Publication date: 2020-03-19
Anticipated expiration: 2021-03-10
Also published as: US20210370468A1

Abstract

A wet abrasive blasting system includes a vessel having multiple outlets for dispensing slurry. A first sprayer of the system is operatively associated with a first blast control switch, and a second sprayer is operatively associated with an n-th blast control switch. A first blast line fluidly connecting the first sprayer to the first outlet includes a first pinch valve, and an n-th blast line fluidly connecting the n-th sprayer to the n-th outlet includes an n-th pinch valve. A time delay module of the system transmits signals to close all system pinch valves upon receipt of signals indicative of an actuated state of more than one blast control switch and, after a predetermined time delay, transmits signals to open all system pinch valves associated with their respective actuated blast control switches.

Description

MULTI-OUTLET PRESSURE VESSEL, SYSTEM, AND METHOD FOR WET

ABRASIVE BLASTING

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit of U.S. Provisional Application No. 62/729,017 filed September 10, 2018 for“MULTI-OUTLET PRESSURE VESSEL FOR WET ABRASIVE BLASTING” by N. K. Studt, B. J. Kapinski, N. M. Hickman, A. J. Daeger and P. W. Ackerman.

FIELD OF INVENTION

The invention is directed to abrasive blasting systems for cleaning, preparing surfaces, removing coatings, and other abrasive blasting operations. Embodiments of the wet abrasive blasting system and methods provide consistent flow of air, water, and abrasive for multiple outlets.

BACKGROUND

To remove the paint, dirt, or other surface coating from a substrate such as a surface to be painted or cleaned, a blasting system may be both desirable and necessary. There are a variety of blasting processes for these purposes, including but not limited to, water blasting, dry abrasive blasting, and wet abrasive blasting. In certain applications, abrasive blasting systems are able to efficiently clear or remove a coating without damaging the underlying metal or other substrate. Although in other applications, a certain degree of surface roughening may be desired.

The use of dry abrasive blasting with particles such as those used in conventional sand blasting may result in surface roughness and other damage to the substrate. Typical blast particles are hard and abrasive in order to increase the efficiency of the blasting operation but therefore may result in damage to the substrate. Soft recyclable blast particles are sometimes substituted to avoid surface damage. These recyclable blast particles include, but are not limited to, agricultural products such as crushed walnut shells, crushed pistachio shells, and rice hulls. Plastic particles are sometimes used to reduce substrate surface damage but may also result in a reduction in efficiency of the blasting operation.

Wet abrasive systems have been used to also control surface damage. Wet abrasive systems combine the benefits of these blasting systems and dry abrasive blasting systems. In wet abrasive blasting, the fluid may encapsulate the abrasive media to simultaneously add mass to the abrasive and buffer the impact of the abrasive against the substrate to reduce potential surface damage but still effectively strip or clean the surface while also reducing the dust produced compared to a dry abrasive blasting system. However, wet abrasive systems require efficient mixing of slurry and a gas stream to produce a consistent stream of a three-phase mixture of fluid, solid abrasive, and gas stream. If the mixing of slurry and pressurized gas is not well controlled, the blasting process is less efficient and the benefits of a wet abrasive system are not fully realized. For many large blasting projects, multiple operators are needed to efficiently complete the project. As such, there is a need for an abrasive system that allows for multiple operators using a single system.

SUMMARY

In one exemplary embodiment, a wet abrasive blasting system includes a vessel having a first outlet and a second outlet for dispensing slurry. The wet abrasive blasting system can further include a first sprayer operatively associated with a first blast control switch and a second sprayer operatively associated with a second blast control switch. A first blast line fluidly connecting the first sprayer to the first vessel outlet includes a first pinch valve, and a second blast line fluidly connecting the second sprayer to the second vessel outlet includes a second pinch valve. A time delay module of the system transmits signals to close all system pinch valves upon receipt of signals indicative of an actuated state of more than one blast control switch. The time delay module further transmits signals to open all system pinch valves associated with their respective actuated blast control switches after a predetermined time delay following the receipt of signals indicative of an actuated state of more than one blast control switch.

An exemplary method includes receiving first and second blast signals indicative of actuated first and second blast control switches, each blast control switch operatively associated with a different sprayer fluidly connected to a different outlet of a pressure vessel or blasting pot. The method further includes transmitting signals from a time delay module to close both pinch valves upon receipt of signals indicative of actuated first and second blast control switches contemporaneously and transmitting signals from the time delay module to open the first and second pinch valves after a predetermined time delay following receipt of signals indicative of actuated first and second blast control switches.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exemplary schematic of a single pump configuration of a multiple outlet blast system. FIG. 2 is an exemplary schematic of a multiple pump configuration of a multiple outlet blast system.

FIG. 3A-3D are exemplary pressure vessel configurations with multiple outlets of a multiple outlet blast system.

DETAILED DESCRIPTION

As described herein, examples of wet abrasive blasting systems include at least one pressure vessel (or blast pot) equipped with multiple outlets, each outlet supplying a different sprayer for dispensing a wet abrasive blast media composed of a mixture of compressed a ir, water, and abrasive media.

In one example, the wet abrasive blasting system includes a logic module and a time delay module that are responsive to blast control switches, each blast control switch associated with a different sprayer connected to a different outlet of a vessel. The blast control switches being associated with the sprayers relates to the function of controlling a sprayer by the respective switch. The logic module and the time delay module each include a network of analog logic components or a digital logic module configured to delay introduction of abrasive media into the blast lines, or delay water delivery to the vessel (or blast pot). Delaying the introduction of the abrasive media into the blast lines allows the vessel pressure to equalize with fluid delivery lines upstream of the vessel while delaying introduction of water into the vessel permits the vessel pressure to equalize with blast lines downstream from the vessel (or blast pot).

In other examples, the wet abrasive system includes a vessel with outlets arranged according to spacing requirements, a baffle positioned between at least two outlets, or a combination of outlet spacing and baffle arrangements. Vessels of this type can be configured to look like a standard vessel externally except for having two or more outlets at the bottom of the vessel. Internally, the baffles, outlet spacing, or a combination of both facilitate a consistent media flow such that each outlet can be independently controlled. In still other examples, two or more vessels can be linked together via pathways for equalizing vessel pressure within an internal volume of the assembly.

Any of these embodiments, as well as embodiments combining features from two or more of the above embodiments, enable multiple operators to perform wet abrasive blasting while limiting the pressure differential between two adjacent vessel outlets or among a group of vessel outlets. The beneficial pressure distributions within the vessel (or blast pot) provide consistent flows of air, water, and abrasive through a single blast line or, additionally, through multiple blast lines during a blasting operation.

FIG. 1 is an exemplary schematic of a single pump blasting system 10 that includes vessel 12 equipped with multiple inlets l4a, l4b, through 14h and multiple outlets l6a, l6b, through 16h. Each blast line l8a, l8b, through 18h of system 10 fluidly connect one of vessel outlets l6a-l6n to one of sprayers 20a-20n. Pump 22 acts on fluid, for example water, received from a fluid source through intake port 22a to deliver pressurized fluid through discharge port 22b. Delivery lines 24a-24n fluidly connect pump discharge port 22b to one of vessel inlets l4a-l4n. Each blast line l8a, l8b, through 18h includes one of pinch valves 26a-26n operable to vary the flow rate through respective blast lines 18a- 18h and one of blast control switches 28a-28n operable to control on-off operation of respective blast lines l8a-l8n. Delivery lines 24a-24n each include one of solenoid valves 30a, 30b, through 30n that provide on-off control of one of delivery lines 24a, 24b, through 24n and flow control valves 32a, 32b, through 32n operable to adjust the flow rate through one of delivery lines 24a, 24b, through 24n. Bypass line 34 fluidly connects pump discharge port 22b to vessel inlet 15 and includes bypass valve 35 to provide on-off control of flow through bypass line 34. Compressed air is provided to sprayers 20a-20n from compressed air source 36 via compressed air lines 38a-38n. Compressed air and slurry combine within sprayers 20a-20n before discharging to perform a wet blasting operation. In order to manage the distribution of slurry and compressed air delivered to sprayers 20a- 20n, blasting system 10 further includes logic module 40 and time delay module 41 configured to control opening and closing of pinch valves 26a-26n, solenoid valves 30a- 30n, and bypass valve 35 in response to actuated or unactuated states of blast control switches 28a-28n.

Blasting system 10 includes at least two blast lines 18a and 18b as well as at least two delivery lines 24a and 24b. However, blasting system 10 can include more than two blast lines and delivery lines. For instance, blasting system 10 can include an arbitrary number (n) of blast lines, delivery lines, and associated solenoid valves, flow control valves, pinch valves, compressed air lines, and blast control switches represented by reference numerals denoted by (n). Accordingly, as blasting system 10 is scaled to include more than two blast lines and associated delivery lines, the required volume of vessel 12 and the required capacity of pump 22 increases. Additionally, pump capacity can be increased by arranging multiple pumps 22 in parallel while increased vessel volume can be provided in a single vessel 12 or with multiple vessels 12 linked together via pressure equalization pathways, as will be discussed in subsequent embodiments.

Vessel (or blast pot) 12 is a pressure vessel manufactured with a top opening and funnel to facilitate filling vessel 12 with abrasive media. As implemented in blast system 10, and subsequently described blast system embodiments, vessel 12 includes at least one inlet 14 and at least two outlets l6a and l6b. Since vessel 12 receives fluid (e.g., water) from multiple delivery lines 24a-24n, embodiments of the blast system that include a single inlet 14 typically include a manifold, a branch connection, or generally another flow-combining element to permit fluid to flow into vessel 12 unimpeded by vessel inlet 14. In other embodiments, multiple inlets l4a-n can be incorporated into vessel 12, for instance, one inlet 14 for each delivery line 24a, 24b, through 24n, or any intermediate number of inlets 14. In an installed orientation, inlet or inlets 14 are positioned in the upper or top half of vessel 12 opposite outlets l6a-l6n positioned on the lower or bottom half to facilitate fluid flow through vessel 12 and mixing of abrasive media to produce slurry (i.e., an abrasive media mixed with and suspended within a fluid) delivered through outlets l6a- 16h.

Blast lines l8a, l8b, through 18h fluidly connect outlets l6a, l6b, through 16h to sprayers 20a, 20b, through 20n. First blast line l8a includes pinch valve 26a and blast control switch 28a. Second blast line l8b includes pinch valve 26b and blast control switch 28b and each additionally blast line 18n includes pinch valve 26n and blast control switch 28n. Each blast line l8a, l8b, through 18h includes similar, if not identical, components that are arranged and function in a similar, if not identical, manner.

Pinch valves 26a, 26b, through 26n each include a flexible valve element (i.e., one of elements 42a, 42b, through 42n) that can be displaced by an actuation force to vary the open area through respective pinch valves 26a, 26b, through 26n. For instance, pinch valve 26a includes flexible valve element 42a that can actuated from a fully-open position (i.e., maximum open area) to a fully-closed position to completely obstruct flow through blast line l8a. Several methods of valve actuation can be used including application of pneumatic or hydraulic pressure to a backside or exterior surface of flexible element 42a. In other embodiments, flexible element 42a can be actuated with an electrically-actuated or other mechanically-driven actuator. An interior surface of flexible element 42a forms a portion of the flow path along blast line l8a. Accordingly, inward deflection of flexible element 42a reduces flow area through pinch valve 26a and outward deflection of flexible element 42a increases flow area through pinch valve 26a. The remaining pinch valves 26b-26n similarly include flexible valve elements 42b-42n and function in the same manner as pinch valve 26a with flexible valve element 42a. By using a pinch valve, the actuation components of the valve are exterior to the flow path and, thus, are not subject to the wear imposed on other types of valves resulting from a flow of abrasive slurry.

Blast control switches 28a, 28b, through 28n are attached to one of sprayers 20a, 20b, through 20n, each including an actuated state and an unactuated state for selective control of a blasting operation. Sprayer 20a receives compressed air through line 38a from compressed air source 36. When blast control switch 28a has an actuated state, a valve within sprayer 20a opens, permitting compressed air to be discharged from sprayer 20a. In an unactuated state, blast control switch 28a closes the sprayer valve to prevent discharging compressed air. Additional sprayers 20b through 20n installed with blasting system 10 are selectively controlled by blast control switches 28b through 28n, respectively, such that compressed air is delivered from source 36 via lines 38b-38n to sprayers 20b-20n in the same manner as sprayer 20a and selectively discharge compressed air via actuation of blast control switches 28b-28n in the same manner as blast control switch 28a.

Logic module 40, time delay module 41 , or both modules 40 and 41 receive a blast signal indicative of blast control switch 28a in an unactuated state or an actuated state as schematically indicated at 44a. Blast signal 44a can be a pneumatic or hydraulic pressure transmitted along a conduit or tube to time delay module 40. For instance, upon actuation of blast control switch 28a, pressure from compressed air within sprayer 20a can be sensed by logic module 40 such that an ambient pressure or neutral gauge pressure indicates an unactuated state of blast control switch 28a and a pressure greater than a predefined threshold indicates an actuated state of blast control switch 28a. In other embodiments, signal 44a can be an analog signal (e.g., a voltage or current) or digital signal (e.g., a high state or a low state) transmitted along a wire or transmitted wirelessly to the time delay module 40. Similarly, time delay module 40 receives blast signals 44b-44n indicative of actuated or unactuated states of blast control switches 28b-28n. As with blast signal 44a, blast signals 44b-44n can be mechanical signals (i.e., pneumatic or hydraulic), analog electrical signals (i.e., a voltage or current), digital electrical signals (i.e., a high state or a low state), or a combination of any of the foregoing types of signals.

Delivery lines 24a, 24b, through 24n fluidly connect pump discharge port 22b to vessel inlets l4a-l4n to provide fluid to vessel 12. Within vessel 12, fluid mixes with abrasive media to create slurry at vessel outlets l6a, l6b, through 16h. Delivery line 24a includes solenoid valve 30a and flow control valve 32a, each disposed along line 24a between pump discharge port 22b and vessel inlet 14. In some examples, solenoid valve 30a is disposed downstream of pump discharge port 22b and upstream from control valve 32a. In other examples, the reverse configuration is used, and solenoid valve 30a is disposed downstream of control valve 32a and upstream from vessel inlet l4a. Each of the other delivery lines 24b through 24n include one of solenoid valves 30b-30n and one of flow control valves 32b-32n that are arranged as described for delivery line 24a.

Solenoid valves 30a, 30b, through 30n are two position valves having an open position for allowing flow through one of delivery lines 24a-24n and a closed position for blocking flow through one of delivery lines 24a-24n. Flow control valves 32a, 32b, through 32n include variable valve elements that can be positioned to adjust a flow rate of water through delivery lines 24a, 24b, through 24n. For example, flow control valve 32a include variable valve element 46a. In an open position of control valve 32a, variable valve element 46a allows water to flow through delivery line 24a unobstructed by valve 32a and at a rate supplied by pump 22. In a closed position of control valve 32a, variable valve element 46a completely obstructs flow through delivery line 24a. At positions of control valve 32a between the open and closed positions, variable valve element 46a partially obstructs flow through delivery line 24a. The pressure drop that results from variable valve element 46a partially obstructing flow reduces the flow rate through delivery line 24a in proportion to the pressure drop through flow control valve 32a. Each of the other flow control valves 32b through 32n include one of variable valve elements 46b-46n, each of variable valve elements 46b-46n having an open position, a closed position, and intermediate positions that adjust the flow through respective delivery lines in the same manner as flow control valve 32a.

Since blasting system 10 includes solenoid valves 30a-30n to open or close flow through delivery lines 24a-24n, flow control valves 32a-32n are adjusted to a set point within a range of intermediate valve positions. Flow control valves 32a-32n can be adjusted manually, such as via a knob, lever, electric or hydraulic actuator, or can be adjusted automatically using an actuator controlled by the time delay module 40. Typically, each flow control valve 32a-32n will be adjusted to permit the same flow rate of water through each delivery line 24a-24n for a selected blasting operation.

Like delivery lines 24a-24n, bypass line 34 fluidly connects pump discharge port 22b to vessel inlet 15 and includes bypass valve 35. Bypass valve 35 is a two-position valve that opens or closes bypass line 34. In the open position, fluid can flow from pump discharge port 22b to vessel inlet 14. In the closed position, fluid cannot flow to vessel inlet 15. In some examples, bypass valve 35 is a solenoid valve. While any suitable flow area can be selected for bypass line 34, bypass line 34 can have more flow area than any one of delivery lines 24a-24n taken individually to permit a higher flow rate into vessel 12 during some operating conditions. For example, bypass line 34 can be sized to permit the maximum flow rate deliverable by pump 22 with minimal pressure loss. To ensure minimal pressure losses, bypass line 34 is sized such that the flow velocity is approximately 1.52 meters per second (or about 5.0 feet per second) or less at the maximum flow rate of pump 22.

Any suitable pump type can be used for pump 22. However, fixed- displacement pumps are particularly suited for blasting system 10. Such fixed- displacement pumps are known in the art and provide a relatively constant volume of pressurized fluid at pump discharge port 22b for each rotation of the pump impeller. Blasting system 10 utilizes a single pump 22. However, as described in subsequent embodiments, multiple pumps can be used.

To prepare blasting system 10 for operation, an operator fills vessel (or blast pot) 12 with abrasive media and seals it with a cover or plunger-style seal that presses against the interior side of the vessel under pressure. Next, the operator connects pump inlet 22a to a fluid source. Subsequently, at least one of blast lines 18 a- 18h is connected to corresponding outlets l6a-l6n of vessel 12. Flow control valves 32a-32n are set to a target flow rate, which in some instances, is the same target flow rate for each delivery line 24a- 24n. The operator activates pump 22 to fill vessel 12 and delivery lines 24a-24n with water and activates compressed air source 36 to pressurize lines 38a-38n. In some instances, the operator prefills vessel 12 with water after filling vessel 12 with abrasive media. Water continues to be pumped into vessel 12 until a target pressure is obtained after which pump 22 operates intermittently to maintain pressure within delivery lines 24a-24n and vessel 12. Automatic pressure stabilization can be achieved with a pressure-responsive shut-off switch at the pump or any other similar control method.

Vessel target pressure is selected to be a gauge pressure that is less than the maximum design pressure of vessel 12 and greater than a blast pressure required to perform a particular blasting operation by at least a minimum amount to account for system pressure losses between vessel 12 and sprayers 20a-20n. The pressure differential between blast pressure and vessel pressure can be affected by blast hose diameter, blast hose length, sprayer nozzle size, blast pressure regulator setting, maximum deliverable flow rate of compressed air source, maximum deliverable flow rate of pump 22, and the number of blast lines in use. In some instances, the target pressure is greater than or equal to 1.00 MPa (145 psig) and less than or equal to 1.38 MPa (200 psig). In other instances, the target pressure is greater than or equal to 1.14 MPa (165 psig) and less than or equal to 1.33 MPa (193 psig). In still other instances, the target pressure is approximately 1.28 MPa (185 psig).

Throughout operation of blasting system 12, logic module 40 and time delay module 41 govern the opening and closing of solenoid valves 30a-30n, pinch valves 26a- 26n, and bypass valve 35. Initially, solenoid valves 30a-30n and pinch valves 26a-26n are in the closed position and blast control switches 28a-28n have an unactuated state. During the preparation phase, logic module 40 receives signals 44a-44n indicative of the unactuated states of blast control switches 28a-28n and, in response, sends signal 46 causing bypass valve 35 to open.

The first blasting operation begins when an operator actuates the first blast control switch to the actuated state. For the purposes of explanation, the first blast control switch is switch 28a, although any of the other blast control switches 28b-28n can be actuated first. When only one of the blast control switches 28a-28n has an actuated state, blasting system 10 functions in much the same way as a conventional blasting system. Accordingly, as soon as blast control switch 28a moves to the actuated state, compressed air discharges from sprayer 20a that is delivered from compressed air source 36 through line 38a. Subsequently, logic module 40 receives signal 44a indicative of the actuated state of blast control switch 28a. In response to signal 44a, logic module 40 opens solenoid valve 30a via opening signal 48a, opens pinch valve 26a via opening signal 50a, and closes bypass valve 35 via closing signal 52. In this single sprayer configuration, pump 22 drives fluid through delivery line 24a into vessel 12 at inlet l4a according to the flow rate set by control valve 32a. Fluid mixes with abrasive media within vessel 12 to create slurry, which is delivered to blast line l8a via outlet l6a. Slurry flows through blast line l8a at a rate governed by pinch valve 26a to sprayer 20a. Within sprayer 20a, slurry mixes with compressed air delivery through line 38a before discharging from sprayer 20a to perform a wet blasting operation.

A second blasting operation begins when another operator actuates a second blast control switch to an actuated state, for example switch 28b. Upon actuation of second blast control switch 28b, compressed air flows through line 38b to sprayer 20b, and logic module 40 receives second blast signal 44b indicative of the actuated state of blast control switch 28b. In response to second blast signal 44b, time delay module 41 transmits closing signal 54a to pinch valve 26a associated with first sprayer 20a, causing pinch valve 26a to close. Concurrently with closing signal 54a, logic module 40 opens solenoid valve 30b via opening signal 48b. With blasting system 10 in this configuration, slurry delivery to sprayer 20a is stopped momentarily while compressed air flows through both sprayers 20a and 20b. Additionally, fluid flows from pump discharge port 22b into vessel 12 through delivery lines 24a and 24b, increasing the pressure within vessel 12. After a predefined time delay, time delay module 41 opens pinch valves 26 a and 26b via opening signals 50a and 50b, respectively, causing slurry to be delivered to sprayers 20a and 20b. There, slurry mixes with compressed air delivered to each sprayer 20a, 20b through lines 38a, 38b before discharging from the sprayers during dual blasting operations.

The duration of the time delay is dependent on various parameters of system 10 including, volume and target pressure of vessel 12, number and pressure loss through each delivery line, and the volumetric flow rate delivered by pump 22. The time delay duration is also dependent on the volumetric flow rate and pressure delivered by compressed air source 36. The time delay duration is selected based on these parameters, and in some embodiments, is greater than a duration of transient operation during which pressure within vessel 12 increases and pressure within compressed air lines 38a-38b stabilizes. Typically, vessel pressure and air pressure stabilize when each is within approximately 10% of target values. In other examples, vessel pressure and air pressure are considered stabilized when each pressure is within 5% of target values. Further, the time delay duration can be a constant value. Alternatively, some systems may have increased or decreased transient operation depending on the number of actuated blast control switches, and accordingly, the time delay module can be configured to increase or decrease the time delay duration based on the number of actuated blast control switches in the blasting system.

Actuation of each subsequent blast control switch up to blast control switch 28n occurs in a similar manner to actuating second blast control switch 28b to the actuated state while first blast control switch 28a is in the actuated state. Accordingly, when an operator actuates any additional blast control switch 28n into an actuated state, compressed air flows into sprayer 20n from compressed air source 36 via line 38n and discharges from sprayer 20n. Additionally, actuating blast control switch 28n into an actuated state transmits blast signal 44n indicative of the state of blast control switch 28n to time delay module 40. Upon receiving blast signal 44n, time delay module 41 transmits closure signal 54a to first pinch valve 26a and transmits closure signal 54b to second pinch valve 26b, causing pinch valves 26a and 26b to close and momentarily stopping slurry flow into sprayers 20a and 20b. Additionally, logic module 40 opens solenoid valve 30n by transmitting opening signal 48n to valve 30n simultaneously or in succession with closure signals 50a-50b. At this stage, solenoid valves 30a, 30b, through 30n are in an open position, and fluid flows from pump discharge port 22b into vessel 12 through delivery lines 24a, 24b, through 24n at flow rates governed by flow control valves 32a, 32b, through 32n. As a result, pressure within vessel 12 increases in much the same manner as described previously, albeit by using more delivery lines than in the previous example and, therefore, pressurization of vessel 12 occurs at an increased rate. Again, after the predefined time delay, time delay module 41 opens pinch valves 26a, 26b, through 26n by transmitting opening signals 54a, 54b, through 54n to respective valves 26a, 26b, through 26n, causing slurry to be delivered to sprayers 20a, 20b, through 20n. After the slurry mixes with compressed air within sprayers 20a, 20b, through 20n, a wet abrasive mixture discharges from each of the sprayers 20a, 20b, and 20n in a multi-sprayer blasting operation.

When one of the operators actuates a blast control switch into an unactuated state, logic module 40 acts to close the pinch valve and solenoid valve associated with that particular blast control switch. For example, when an operator moves blast control switch 28n into the unactuated state, blast signal 44n becomes indicative of an unactuated state rather than an actuated state. Logic module 40 receives an indication of the changed blast control signal 44n and, in response, transmits closure signal 56n to solenoid valve 30n and transmits closure signal 50n to pinch valve 26n. Upon receiving closure signals 56n and 50n, solenoid valve 30n and pinch valve 26n close, stopping the flow of water into vessel 12 through delivery line 24n and the flow of slurry through blast line 18h. In this state, blast system 10 transitions from a multi- spraying operation to a dual-spraying operation.

If in a subsequent operation, an operator actuates blast control 28b to the unactuated state, logic module 40 receives an indication of the unactuated state via blast signal 44b. In response to the unactuated state of blast control switch 28b, logic module 40 closes solenoid valve 30b and closes pinch valve 26b by transmitting closure signals 56b and 50b to respective valves 30b and 26b. Similarly, in response to actuating blast control switch 28a to an unactuated state, logic module 40 closes solenoid valve 30a and pinch valves 26a by transmitting closure signal 56a to solenoid valve 30a and transmitting closure signal 50a to pinch valve 26a. Once all blast control switches 28a-28n return to an unactuated state and all pinch valves 26a-26n as well as all solenoid valves 30a-30n are closed, logic module 40 opens bypass valve 35 by transmitting opening signal 46. In this configuration, the pressure within vessel 12 can be returned to the target pressure between blasting operations. When blasting resumes with the actuation of one of blast control switches 28a-28n, logic module 40 closes bypass valve 35 by transmitting closing signal 52 to bypass valve 35. Thereafter, logic module 40 and time delay sunmodule 41 respond to actuated or unactuated states of blast control switches 28a-28n as described above.

While operations of blasting system 10 are described as actuating blasting control switches 28a-28n in succession, logic module 40 and time delay module 41 do not require blasting control switches 28a-28n to be actuated in a particular order. Instead, blast control switches 28a-28n can be actuated or unactuated in any order. Further, multiple blast control switches 28a-28n can be actuated simultaneously. Accordingly, any combination of actuated and unactuated states of blast control switches 28a-28n is managed by logic module 40 and time delay module 41 in a manner consistent with the above disclosure.

In order to perform the above logic operations, logic module and time delay module 41 can each include a network of analog logic components, such as solenoid valves, shuttle valves, directional control valves, AND valves, OR valves, arranged to perform the logic described above. Actuation of the components can be pneumatic or hydraulic as well as pilot-operated component actuation. For example, AND logic functions can be achieved by arranging two or more solenoid valves in series such that actuation of all valves in the series is required to provide an output. In another example, OR logic functions can be achieved by connecting two solenoid valves in parallel and connecting the outputs of each valve to a shuttle valve that permits a signal from either valve to pass to the output while simultaneously preventing reverse flow through the unactuated solenoid valve. In another OR logic example, multiple solenoid valves can be connected in parallel such that the outputs are joined together, each valve output having a check valve for preventing reverse flow. AND logic and OR logic can also be provided by a single valve equipped with two or more inputs and an output, the valve element permitting flow to the output depending on signals supplied to the inputs. Analog logic networks of this type can be constructed in a variety of arrangements to perform the functions of logic module 40 and time delay module 41.

Alternatively, one or both of logic module 40 and time delay module 41 can include an electronic control module. The electronic control module includes a receiving module configured to receive one or more inputs, an output module configured to transmit one or more outputs, a processor, and a storage unit (e.g., volatile or non-volatile memory) encoded with instructions that, when executed by the processor, perform the logic functions of logic module 40 and time delay module 41. In this instance, pneumatic or hydraulic inputs can be used when the receiving module is appropriately equipped with pressure- sensitive elements at the inputs. More typically, the receiving module as well as the output module are adapted to receive or transmit analog electric signals (e.g., voltage or current signals), digital electric signals (i.e., high or low state signals), or a combination of analog and digital electrical signals.

In some embodiments, logic functions preformed by logic module 40 and time delay module 41 can be performed by independent networks of analog logic components or electronic control modules such that logic module 40 performs control operations of system 10 independently of time delay module 41. In this configuration, time delay module 41 can receive blast signals indpendently of logic module 40 and, in response, transmit opening signals and closing signals to pinch valves 26a-26n as described in reference to system 10. In other embodiments, time delay module 41 can be integrated into logic module 40 as a submodule whereby control operations of logic module 40 and time delay module 41 are performed by a common network of analog components or a common electronic control module.

Blasting system 10 can include a multi-pump configuration in lieu of the single pump configuration depicted by FIG. 1. FIG. 2 is an example of multi-sprayer blasting system lOa incorporating a multiple pump arrangement. Reference numbers used in FIG. 2 that are described with respect to FIG. 1 represent the same components and function in the same manner a previously described. However, in a multi-pump configuration, blasting system lOa includes pumps 60a, 60b, and up to 60n in place of single pump 22 of the single pump configuration, an example of which is depicted in FIG. 1. Each of pumps 60a-60n are fluidly connected to a fluid source at intake ports 62a-62n, and act on fluid received from the fluid source to provide pressurized fluid at a desired flow rate through discharge ports 64a-64n. Similarly, bypass line 34 can be supplied by pump 61, which receives fluid from the source through intake port 6la and provides pressurized fluid at discharge port 6 lb. Using multiple pumps arranged in parallel as shown in FIG. 2 increases the maximum flow rate possible for system 10 relative to a similarly sized single pump or, alternatively, permits the pump capacity of each individual pump to be smaller than a single large pump.

FIG. 3A depicts the effects of adding multiple outlets to a conventional pressure vessel (or blasting pot). Like vessel 12, vessel l2a includes multiple outlets 46a, 46b, 46c, and 46d disposed on a bottom portion of vessel l2a when vessel l2a is in an installed orientation. However, outlets 66a-66d are clustered in a relatively small region of vessel l2a and, as such, slurry does not discharge from vessel l2a at equal volumetric flow rates. As shown by the relative length of each slurry flow arrow 68a, 68b, 68c, and 68d, outlets 66a and 66d located around a periphery of the outlet region dispense more slurry than outlets 66b and 66c located interior to outlets 66a and 66d. This skewed distribution results from the relatively close proximity of a clustered outlet configuration.

Separation of vessel outlets is critical to avoid unequal distribution of slurry delivered through the outlets. Unequal slurry distribution occurs when a pressure differential exists between or among the outlets. Without addressing the pressure differential, the blast line with the largest pressure differential robs slurry from the other lines (or outlets) as illustrated in FIG. 3A.

FIGs. 3B depicts an exemplary pressure vessel (or blasting pot) configuration that improves slurry delivery distribution and, thus, is suitable for use in multi-spraying blasting systems (e.g., systems 10 and lOa). FIG. 3B depicts exemplary vessel l2b that includes at least two outlets 70a and 70b and at least one internal baffle 72. Outlets 70a and 70b are disposed in a bottom region of vessel l2b when vessel l2b is in an installed orientation for the same reasons described for vessel 12. Baffle 72 is disposed between outlets 70a and 70b, extending inwards from an interior side of vessel l2b to partition a portion of interior volume 74 of vessel l2b into volumes 74a and 74b. Because baffle 72 does not partition vessel volume 74 completely, volume 74c fluidly communicates with both volume 74a and 74b. For this reason, one or more inlets 14 of vessel l2b are located at a boundary of vessel volume 74c. Outlet 70a extends through vessel l2b at a boundary of volume 74a such that volume 74a is immediately adjacent to and communicates directly with outlet 74a. Similarly, outlet 70b extends through vessel l2b at a boundary of volume 74b such that volume 74b is immediately adjacent to and communicates directly with outlet 74a. Because baffle 72 prevents slurry from flowing directly between outlets 70a-70b (i.e., directly from vessel volume 74a to vessel volume 74b or vice versa), slurry discharged through outlet 70a is approximately equal to slurry discharged through outlet 70b.

Baffle 72 seeks to equalize the amounts of slurry discharged through outlets 70a and 70b and, thus, in the depicted example, is positioned approximately half way between outlets 70a and 70b as determined by a linear distance measured between geometric centerlines of outlets 70a and 70b. However, depending on local flow conditions, baffle 72 can be positioned at any position between adjacent outlets that equalizes the slurry discharge rates through two or more outlets.

Additionally, while a single baffle 72 is depicted by FIG. 3B, any number of baffles 72 can be arranged within vessel l2b. For example, vessel l2b can include additional outlets 70c and 70d that are arranged such that outlets 70a, 70b, 70c, and 70d are equally spaced from each adjacent outlet to position each one of outlets 70a, 70b, 70c, and 70d in a different quadrant of vessel l2b. In this example, baffle 72 can include two baffle walls that intersect to form an X-shape or cross shape. Other configurations of baffle 72 may include a central wall circumscribing a central portion of vessel volume 74 disposed at the bottom center of vessel l2b in the installed condition (e.g., a cylindrical wall extending from the bottom-most interior surface of vessel l2b). Multiple linear walls extend outward from the central wall to the interior surface of vessel l2b. With this configuration, an outlet can be centrally-located at the bottom-most portion of vessel l2b and additional outlets can be disposed within each of the volume partitions defined by two adjacent linear walls and a portion of the central wall.

FIG. 3C depicts another exemplary pressure vessel (or blasting pot) configuration that can be used in multi- spraying blasting systems. In this example, vessel l2c includes at least two outlets (three outlets 76a, 76b, and 76c are shown), and vessel l2c is sufficiently large to enable outlets 76a, 76b, and 76c to be spaced by a minimum spacing criterion. For example, in the example depicted by FIG. 3C, outlet 76a extends through vessel l2c at a central location of a bottom-most portion of vessel l2c in an installed orientation. Outlets 76b and 76c are spaced from outlet 76a such that approximately one third of cross-sectional area of vessel l2c taken normal to a longitudinal direction of vessel l2c is allocated to each of outlets 76a, 76b, and 76c. As a result, slurry delivered through each outlet 76a, 76b, and 76c are approximately equal or have less than or equal to a 5% flow deviation.

FIG. 3D depicts yet another exemplary pressure vessel (or blasting pot) configuration that can be used in multi-spraying blasting systems. In this example, two or more vessels l2d are joined together by pathways 78, each pathway 78 extending between two vessels l2d placing an internal volume of each vessel l2d in communication with another vessel l2d. For each vessel l2d, a single outlet 80 is placed in a bottom region of vessel l2d when vessel l2d is in an installed orientation. While two vessels l2d are shown linked via pathway 78 in FIG. 3D, additional vessels l2d can be joined to the assembly, each additional vessel l2d directly linked to an adjacent vessel l2d and, thus, to every other vessel l2d in the assembly.

Whether one or multiple pathways 78 are used, each pathway 78 has a cross- sectional area sized to provide minimal pressure drop between adjacent vessels l2d. The amount of permissible pressure drop through pathway 78 will be system dependent and is generally proportional to a flow velocity through the pathway 78. Typically, flow velocities less than 1.52 meters per second (or about 5.0 feet per second) result in a pressure loss through pathwa blast signal y 78 that permits the discharging vessel pressure to equalize with the stagnate vessel.

In addition to vessels depicted in FIGs. 3B, 3C, and 3D, other suitable vessel configurations can include a combination of aspects of one or more of the foregoing examples. For instance, a baffle configuration from vessel l2b can be combined with spacing requirements from vessel l2c to further improve uniformity of slurry delivery among multiple vessel outlets. In another combination, baffle requirements from vessel l2b, spacing requirements from vessel l2c, or a combination of baffles and spacing requirements can be combined with multiple vessel arrangements depicted by FIG. 3D. Single vessel systems allow blasting systems to have improved ease of use and a reduced form factor relative to multi- vessel blasting systems whereas multi- vessel blasting systems provide improved flow distribution and blasting capacity.

Any of the vessel configurations can be used to facilitate operation of a multi-sprayer blasting system such as those described by this disclosure. Separation of vessel outlets provided for by internal baffles, minimum spacing requirements, or multi vessel assemblies allow blast pressure differentials between or among sprayers of up to 0.14 MPa (or about 20 psig) depending on the size of the compressed air source. Furthermore, blasting system configurations in accordance with aspects of this disclosure permit multiple blast lines to operate independently and at varying pressures.

Discussion of Possible Embodiments

The following are non-exclusive descriptions of possible embodiments of the present invention.

A wet abrasive blasting system according to an exemplary embodiment of this disclosure, among other possible things, includes a vessel comprising a first outlet and a second outlet for providing a slurry. The wet abrasive system of the preceding paragraph can optionally include, additionally, and/or alternatively, any one or more of the following steps, features, configurations and/or additional components:

A further embodiment of the foregoing wet abrasive blasting system can further include a first sprayer operatively associated with a first blast control switch.

A further embodiment of any of the foregoing wet abrasive blasting systems can further include a second sprayer operatively associated with a second blast control switch.

A further embodiment of any of the foregoing wet abrasive blasting systems can further include a first pinch valve disposed along a first blast line fluidly connecting the first sprayer to the first outlet of the vessel.

A further embodiment of any of the foregoing wet abrasive blasting system can further include a second pinch valve disposed along a second blast line fluidly connecting the second sprayer to the second outlet of the vessel.

A further embodiment of any of the foregoing wet abrasive blasting systems can further include a logic module and a time delay module.

A further embodiment of any of the foregoing wet abrasive blasting systems, wherein the logic module can be configured to receive a first blast signal indicative of an actuated state of the first blast control switch.

A further embodiment of any of the foregoing wet abrasive blasting systems, wherein the logic module can be configured to receive a second blast signal indicative of an actuated state of the second blast control switch.

A further embodiment of any of the foregoing wet abrasive blasting systems, wherein upon receiving the second blast signal by the logic module during the actuated state of the first blast control switch, the time delay module can be configured to transmit a first closure signal to the first pinch valve to close the first pinch valve.

A further embodiment of any of the foregoing wet abrasive blasting systems, wherein upon receipt of the second blast signal by the logic module during the actuated state of the first blast control switch, the time delay module can be configured to transmit a second closure signal to the second pinch valve to maintain the second pinch valve in a closed position.

A further embodiment of any of the foregoing wet abrasive blasting systems, wherein the time delay module can be configured to transmit first and second opening signals to first and second pinch valves, respectively, to open the first and second pinch valves after a predetermined time delay starting upon receipt of the second blast signal.

A further embodiment of any of the foregoing wet abrasive blasting systems can further include a pump comprising an intake port in fluid communication with a fluid source and a discharge port.

A further embodiment of any of the foregoing wet abrasive blasting systems can further include a first solenoid valve positioned along a first delivery line fluidly connecting the pump discharge port to an inlet of the vessel.

A further embodiment of any of the foregoing wet abrasive blasting systems can further include a second solenoid valve positioned along a second delivery line fluidly connecting the pump discharge port to the vessel inlet.

A further embodiment of any of the foregoing wet abrasive blasting systems, wherein the logic module can be configured to transmit a third opening signal to the first solenoid valve to open the first solenoid valve upon receiving the first blast signal.

A further embodiment of any of the foregoing wet abrasive blasting systems, wherein the logic module can be configured to transmit a fourth opening signal to the second solenoid valve to open the second solenoid valve upon receiving the second blast signal.

A further embodiment of any of the foregoing wet abrasive blasting systems, wherein the logic module can be configured to transmit a third closure signal to the first pinch valve to close the first pinch valve upon receiving a third blast signal indicative of an unactuated state of the first blast control switch.

A further embodiment of any of the foregoing wet abrasive blasting systems, wherein the logic module can be configured to transmit a fourth closure signal to the first solenoid valve to close the first solenoid valve upon receiving the third blast signal.

A further embodiment of any of the foregoing wet abrasive blasting systems, wherein upon receiving a fourth blast signal indicative of an unactuated state of the second blast control switch, the logic module can be configured to transmit a fifth closure signal to the second pinch valve and transmit a sixth closure signal to the second solenoid valve to close the second pinch valve and the second solenoid valve.

A further embodiment of any of the foregoing wet abrasive blasting systems, wherein the logic module can be configured to open a bypass valve positioned along a bypass line fluidly connecting the pump discharge port to the vessel inlet upon receiving blast signals indicative of unactuated states of all blast control switches. A further embodiment of any of the foregoing wet abrasive blasting systems can further include a compressed air source.

A further embodiment of any of the foregoing wet abrasive blasting systems can further include a first compressed air line fluidly connecting the compressed air source to the first sprayer.

A further embodiment of any of the foregoing wet abrasive blasting systems can further include a second compressed air line fluidly connecting the compressed air source to the second sprayer.

A further embodiment of any of the foregoing wet abrasive blasting systems, wherein the first compressed air line can fluidly connect with the first blast line at the first sprayer.

A further embodiment of any of the foregoing wet abrasive blasting systems, wherein the second compressed air line can fluidly connect with the second blast line at the second sprayer.

A further embodiment of any of the foregoing wet abrasive blasting systems, wherein the actuated state of the first blast control switch can discharge compressed air from the first sprayer.

A further embodiment of any of the foregoing wet abrasive blasting systems, wherein the actuated state of the second blast control switch can discharge compressed air from the second sprayer.

A further embodiment of any of the foregoing wet abrasive blasting systems, wherein the vessel can include a partial internal partition, the internal partition defining a first volume that includes the first outlet and a second volume that includes the second outlet, and wherein the vessel includes a third volume fluidly connecting the first volume to the second volume.

A further embodiment of any of the foregoing wet abrasive blasting systems can further include a first regulating valve along the first delivery line having a first adjustable valve element operable to adjust a first flow rate within the first delivery line.

A further embodiment of any of the foregoing wet abrasive blasting systems can further include a second regulating valve along the second delivery line having a second adjustable valve element operable to adjust a second flow rate with the second delivery line.

A further embodiment of any of the foregoing wet abrasive blasting systems, wherein the predetermined time delay can be greater than a time required for the pump to increase a pressure with the vessel to a target operating pressure sufficient to operate the first sprayer and the second sprayer at a target flow rate.

A further embodiment of any of the foregoing wet abrasive blasting systems, wherein the time delay module can be a submodule of the logic module.

A method according to another exemplary embodiment of this disclosure, among other possible things, includes receiving a first blast signal indicative of an actuated state of a first blast control switch by a logic module and receiving a second blast signal indicative of an actuated state of a second blast control switch by the logic module. The method further includes transmitting a first closure signal from a time delay module to a first pinch valve and transmitting a second closure signal from the time delay module to a second pinch valve upon receipt of the second blast control signal by the logic module during the actuated state of the first blast control switch.

The method of the preceding paragraph can optionally include, additionally, and/or alternatively, any one or more of the following steps, features, configurations and/or additional components:

A further embodiment of the foregoing method, wherein the first blast control switch can be operatively associated with a first sprayer, the first sprayer fluidly connected to a first outlet of a vessel by a first blast line.

A further embodiment of any of the foregoing methods, wherein the second blast control switch can be operatively associated with a second sprayer, the second sprayer fluidly connected to a second outlet of the vessel by a second blast line.

A further embodiment of any of the foregoing methods and can further include transmitting a first opening signal from the time delay module to a first pinch valve disposed along the first blast line and transmitting a second opening signal from the time delay module to the second pinch valve after a predetermined time delay starting upon receipt of the second blast signal.

A further embodiment of any of the foregoing methods and can further include transmitting, upon receipt of the first blast signal, a third opening signal from the logic module to a first solenoid valve positioned along a first delivery line fluidly connecting a pump discharge port to an inlet of the vessel, wherein the third opening signal opens the first solenoid valve.

A further embodiment of any of the foregoing methods and can further include transmitting a third closure signal to the first pinch valve upon receiving a third blast signal indicative of an unactuated state of the first blast control switch, wherein the third closure signal closes the first pinch valve.

A further embodiment of any of the foregoing methods and can further include transmitting a fourth closure signal from the logic module to the first solenoid valve upon receipt of the third blast signal by the logic module, wherein the fourth closure signal closes the first solenoid valve.

A further embodiment of any of the foregoing methods and can further include transmitting a fifth closure signal from the logic module to the second solenoid valve and transmitting a sixth closure signal from the time delay module to the second pinch valve upon receiving a fourth blast signal indicative of an unactuated state of the second blast control switch, wherein the fifth closure signal closes the second solenoid valve, and the sixth closure signal closes the second pinch valve.

A further embodiment of any of the foregoing methods and can further include opening a bypass valve using the logic module upon receipt of signals indicative of closed states of all blast control switches, wherein the bypass valve is positioned along a bypass line fluidly connecting the pump discharge port to the vessel inlet.

A further embodiment of any of the foregoing methods and can further include supplying compressed air from a compressed air source to the first sprayer along a first compressed air line in response to the first blast control switch in the actuated state.

A further embodiment of any of the foregoing methods and can further include supplying compressed air from the compressed air source to the second sprayer along a second compressed air line in response to the second blast control switch in the actuated state.

A further embodiment of any of the foregoing methods, wherein the first and second compressed air lines fluidly connect to the first and second blast lines, respectively, at the first and second sprayers, respectively.

A further embodiment of any of the foregoing methods and can further include setting a first flow rate through the first delivery line with a first adjustable valve element of a first regulating valve disposed along the first delivery line.

A further embodiment of any of the foregoing methods and can further include setting a second flow rate through the second delivery line with a second adjustable valve element of a second regulating valve disposed along the second delivery line.

A further embodiment of any of the foregoing methods, wherein the predetermined time delay is greater than a time required for the pump to increase a pressure within the vessel to a target operating pressure sufficient to operate the first sprayer and the second sprayer at a target flow rate.

A further embodiment of any of the foregoing methods, wherein the time delay module can be a submodule of the logic module.

The described wet abrasive blasting systems and methods are not limited to the particular embodiments, method steps, and materials disclosed herein as such formulations, process steps, and materials may vary somewhat. Moreover, the terminology employed herein is used for the purpose of describing exemplary embodiment only, and the terminology is not intended to be limiting since the scope of the various embodiments of the present invention will be limited only by the appended claims and equivalents thereof.

Therefore, while embodiments of the invention are described with reference to exemplary embodiments, those skilled in the art will understand that variation and modifications can be affected within the scope of the invention as defined in the appended claims. Accordingly, the scope of the various embodiments of the present invention should not be limited to the above discussed embodiments, and should only be defined by the following claims and all equivalents.

Claims

CLAIMS:

1. A wet abrasive blasting system comprising:

a vessel comprising a first outlet and a second outlet for providing a slurry;

a first sprayer operatively associated with a first blast control switch;

a second sprayer operatively associated with a second blast control switch;

a first pinch valve disposed along a first blast line fluidly connecting the first sprayer to the first outlet;

a second pinch valve disposed along a second blast line fluidly connecting the second sprayer to the second outlet;

a logic module configured to:

receive a first blast signal indicative of an actuated state of the first blast control switch; and

receive a second blast signal indicative of an actuated state of the second blast control switch; and

a time delay module wherein:

upon receipt of the second blast signal during the actuated state of the first blast control switch by the logic module, the time delay module is configured to:

transmit a first closure signal to the first pinch valve to close the first pinch valve; and

transmit a second closure signal to the second pinch valve to maintain the second pinch valve in a closed position; and after a predetermined time delay starting upon receipt of the second blast signal, the time delay module is further configured to:

transmit first and second opening signals to first and second pinch valves, respectively, to open the first and second pinch valves.

2. The wet abrasive blasting system of claim 1 and further comprising:

a pump comprising an intake port in fluid communication with a fluid source and a discharge port;

a first solenoid valve positioned along a first delivery line fluidly connecting the pump discharge port to an inlet of the vessel; and

a second solenoid valve positioned along a second delivery line fluidly connecting the pump discharge port to the vessel inlet; wherein, upon receiving the first blast signal, the logic module is configured to transmit a third opening signal to the first solenoid valve to open the first solenoid valve; and

wherein, upon receiving the second blast signal, the logic module is configured to transmit a fourth opening signal to the second solenoid valve to open the second solenoid valve.

3. The wet abrasive blasting system of claim 2, wherein the logic module is further configured to:

transmit a third closure signal to the first pinch valve to close the first pinch valve upon receiving a third blast signal indicative of an unactuated state of the first blast control switch.

4. The wet abrasive blasting system of claim 3, wherein upon receiving the third blast signal, the logic module is further configured to:

transmit a fourth closure signal to the first solenoid valve to close the first solenoid valve.

5. The wet abrasive blasting system of claim 4, wherein upon receiving a fourth blast signal indicative of an unactuated state of the second blast control switch, the logic module is further configured to:

transmit a fifth closure signal to the second pinch valve and transmit a sixth closure signal to the second solenoid valve to close the second pinch valve and the second solenoid valve.

6. The wet abrasive blasting system of claim 5 , wherein the logic module is configured to open a bypass valve positioned along a bypass line fluidly connecting the pump discharge port to the vessel inlet upon receiving blast signals indicative of unactuated states of all blast control switches.

7. The wet abrasive blasting system of claim 1 and further comprising:

a compressed air source;

first and second compressed air lines fluidly connecting the compressed air source to the first and second sprayers, respectively;

wherein the first and second compressed air lines fluidly connect with the first and second blast lines, respectively, at the first and second sprayers, respectively;

wherein the actuated state of the first blast control switch discharges compressed air from the first sprayer; and wherein the actuated state of the second blast control switch discharges compressed air from the second sprayer.

8. The wet abrasive blasting system of claim 1, wherein the vessel includes a partial internal partition, the internal partition defining a first volume that includes the first outlet and a second volume that includes the second outlet, and wherein the vessel includes a third volume fluidly connecting the first volume to the second volume.

9. The wet abrasive blasting system of claim 2 and further comprising:

a first regulating valve along the first delivery line having a first adjustable valve element operable to adjust a first flow rate within the first delivery line; and a second regulating valve along the second delivery line having a second adjustable valve element operable to adjust a second flow rate with the second delivery line.

10. The wet abrasive blasting system of claim 2, wherein the predetermined time delay is greater than a time required for the pump to increase a pressure within the vessel to a target operating pressure sufficient to operate the first sprayer and the second sprayer at a target flow rate.

11. A method controlling a wet abrasive system, the method comprising:

receiving a first blast signal indicative of an actuated state of a first blast control switch at a logic module, wherein the first blast control switch is operatively associated with a first sprayer, the first sprayer fluidly connected to a first outlet of a vessel by a first blast line;

receiving a second blast signal indicative of an actuated state of a second blast control switch at the logic module, wherein the second blast control switch is operatively associated with a second sprayer, the second sprayer fluidly connected to a second outlet of the vessel by a second blast line;

transmitting, upon receipt of the second blast control signal by the logic module during the actuated state of the first blast control switch, a first closure signal from a time delay module to a first pinch valve and a second closure signal from the time delay module to a second pinch valve, wherein the first and second closure signals close the first pinch valve and the second pinch valve, respectively, and wherein the first pinch valve is disposed along the first blast line, and the second pinch valve is disposed along the second blast line; transmitting, after a predetermined time delay starting upon receipt of the second blast signal, a first opening signal from the time delay module to the first pinch valve and a second opening signal from the time delay module to the second pinch valve.

12 The method of claim 11 and further comprising:

transmitting a third opening signal from the logic module to a first solenoid valve upon receipt of the first blast signal, wherein the third opening signal opens the first solenoid valve, and wherein the first solenoid is positioned along a first delivery line fluidly connecting a pump discharge port to an inlet of the vessel.

13. The method of claim 12 and further comprising:

transmitting a third closure signal to the first pinch valve upon receiving a third blast signal indicative of an unactuated state of the first blast control switch by the logic module, wherein the third closure signal closes the first pinch valve.

14. The method of claim 13 and further comprising:

transmitting a fourth closure signal from the logic module to the first solenoid valve upon receipt of the third blast signal by the logic module, wherein the fourth closure signal closes the first solenoid valve.

15. The method of claim 15 and further comprising:

transmitting a fifth closure signal from the logic module to the second solenoid valve and transmitting a sixth closure signal from the logic module to the second pinch valve upon receiving a fourth blast signal indicative of an unactuated state of the second blast control switch, wherein the fifth closure signal closes the second solenoid valve, and the sixth closure signal closes the second pinch valve.

16. The method of claim 16 and further comprising:

opening a bypass valve using the logic module upon receipt of blast signals indicative of unactuated states of all blast control switches, wherein the bypass valve is positioned along a bypass line fluidly connecting the pump discharge port to the vessel inlet.

17. The method of claim 11 and further comprising:

supplying compressed air from a compressed air source to the first sprayer along a first compressed air line in response to the first blast control switch in the actuated state; and supplying compressed air from the compressed air source to the second sprayer along a second compressed air line in response to the second blast control switch in the actuated state;

wherein the first and second compressed air lines fluidly connect with the first and second blast lines, respectively, at the first and second sprayers, respectively.

18. The method of claim 12 and further comprising:

setting a first flow rate through the first delivery line with a first adjustable valve element of a first regulating valve disposed along the first delivery line; and setting a second flow rate through the second delivery line with a second adjustable valve element of a second regulating valve disposed along the second delivery line.

19 The method of claim 12, wherein the predetermined time delay is greater than a time required for the pump to increase a pressure within the vessel to a target operating pressure sufficient to operate the first sprayer and the second sprayer at a target flow rate. 20. A wet abrasive blasting system comprising:

a vessel comprising a first outlet and a second outlet for providing a slurry and an inlet;

a first sprayer operatively associated with a first blast control switch;

a second sprayer operatively associated with a second blast control switch;

a second pinch valve disposed along a second blast line fluidly connecting the second sprayer to the second outlet; and

a first compressed air line fluidly connecting the first sprayer to a compressed air source;

a second compressed air line fluidly connecting the second sprayer to the compressed air source;

a first solenoid valve positioned along a first delivery line fluidly connecting the pump discharge port to the vessel inlet;

a second solenoid valve positioned along a second delivery line fluidly connecting the pump charge the vessel inlet; a logic module comprising configured to:

receive a first blast control signal indicative of an actuated state of the first blast control switch;

transmit, upon receipt of the first blast signal, a first opening signal to the first pinch valve and a second opening signal to the first solenoid valve; and

receive a second blast control signal indicative of an actuated state of the second blast control switch after receiving the first blast control signal and during the actuated state of the first blast control switch; and

a time delay module that, upon receipt of the second blast signal, is configured to: transmit a first closure signal to close the first pinch valve and transmit a third opening signal to open the second solenoid valve; and transmit fourth and fifth opening signals to open first and second pinch valves, respectively, after a predetermined time delay starting upon receipt of the second blast signal.