Valve Assembly

Abstract

To prevent a proportional pressure controller from increasing in weight and cost.SOLUTION: A valve assembly 10 comprises a plurality of filling valves 20 which let fluid flow from a fluid inflow hole to an internal flow passage to increase pressure of the fluid output from a fluid outflow hole; a plurality of discharge valves 22 which let fluid flow from the internal flow passage to a discharge hole to lower the pressure of the fluid output from the fluid outflow hole. The valve assembly comprises a controller 24 which is configured to receive a command signal including desired pressure of the fluid output from the fluid outflow hole, and receive a signal indicative of actual pressure of the fluid output from the fluid outflow hole from a pressure sensor 26, and the controller is configured to selectively open and close, based upon a comparison between the command signal and the signal indicative of the actual pressure, the respective filling valves and the respective discharge valves selectively until the actual pressure reaches the desired pressure.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a digital proportional pressure controller for use, for example, in a fluid valve. [Background technology]

[0002] This section provides background information related to the present disclosure that is not necessarily prior art.

[0003] Proportional pressure controllers often include a main internal valve that can be moved to allow pressurized fluid to be discharged to a pressure-controlled device. Such proportional pressure controllers regulate the operating pressure of the pressurized fluid in the pressure-controlled device. The main valve is typically repositioned using a solenoid operator. This configuration adds weight and cost to the proportional pressure controller and requires a significant amount of electrical current to reposition the main valve.

[0004] Additionally, known proportional pressure controllers are prone to system pressure undershoot or overshoot. Due to the mass and operating time of the main valve, the signal to control the main valve to reduce or stop the flow of pressurized fluid to the pressure-controlled device may occur too early or too late to prevent the desired operating pressure from being reached or exceeded. When this occurs, the control system operating the solenoid actuator begins a rapid opening and closing sequence as the controller "hunts" for the desired operating pressure. This rapid action, known as "motor-boating," increases wear and operating costs associated with proportional pressure controllers.

[0005] Known proportional pressure controllers often include an inlet port, an outlet port, and an outlet port. Typically, high-pressure fluid is supplied to the inlet port, passes through the proportional pressure controller, and then exits the fluid through the outlet port to a pressure-controlled device, with excess fluid pressure vented from the proportional pressure controller through the outlet port. Another challenge with known proportional pressure controllers is the difficulty of achieving zero pressure at the outlet port of the proportional pressure controller, even when a zero-pressure condition is desired at the outlet port. The inability to achieve zero pressure at the outlet port of the proportional pressure controller can adversely affect the operation and / or performance of the pressure-controlled device.

[0006] Additionally, fluid may backflow from the pressure-operated device back out the outlet and re-enter the proportional pressure controller, which is undesirable as the return flow of fluid may be contaminated / dirty and may adversely affect the pressure sensor of the proportional pressure controller. Summary of the Invention

[0007] This section provides a general summary of the disclosure and is not an exhaustive disclosure of its complete scope or all of its features.

[0008] According to the present disclosure, there is provided a valve assembly including a plurality of fill valves that allow fluid to flow from a fluid inlet port to an internal flow passage to increase the pressure of the fluid output from a fluid outlet port, and a plurality of discharge valves that allow fluid to flow from the internal flow passage to a discharge port to decrease the pressure of the fluid output from the fluid outlet port, the valve assembly including a controller configured to receive a command signal including a desired pressure of the fluid output from the fluid outlet port and a signal indicative of the actual pressure of the fluid output from the fluid outlet port from a pressure sensor, the controller being configured to selectively open or close each of the fill valves and each of the discharge valves based on a comparison of the command signal with the signal indicative of the actual pressure until the actual pressure equals the desired pressure.

[0009] Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. [Brief explanation of the drawings]

[0010] The drawings described herein are intended to illustrate only selected embodiments rather than all possible implementations and are not intended to limit the scope of the present disclosure.

[0011] [Figure 1] 1 is a schematic diagram of an exemplary valve assembly in accordance with the principles of the present disclosure. [Figure 2] FIG. 1 is a schematic diagram of a controller for an exemplary valve assembly. [Figure 3] FIG. 1 is a schematic diagram of a valve assembly when used to rapidly pressurize a fluid. [Figure 4] FIG. 1 is a schematic diagram of a valve assembly when used to pressurize a fluid at low velocity. [Figure 5] FIG. 1 is a schematic diagram of a valve assembly when used to slowly depressurize a fluid. [Figure 6] FIG. 1 is a schematic diagram of a valve assembly when used to rapidly depressurize a fluid. [Figure 7] FIG. 1 is a schematic diagram of another exemplary valve assembly in accordance with the principles of the present disclosure. [Figure 8] FIG. 1 is a schematic diagram of a valve assembly when used to rapidly pressurize a fluid. [Figure 9] FIG. 9 is a schematic diagram of the valve assembly when used to pressurize a fluid rapidly, but at a slower rate compared to FIG. 8. [Figure 10] FIG. 1 is a schematic diagram of a valve assembly when used to pressurize a fluid at low velocity. [Figure 11] FIG. 11 is a schematic diagram of the valve assembly when used to pressurize fluid at low velocity and at a slower rate compared to FIG. 10. [Figure 12] FIG. 10 is a schematic diagram of the valve assembly when the fluid pressure is at a desired pressure. [Figure 13] FIG. 1 is a schematic diagram of a valve assembly when used to slowly depressurize a fluid. [Figure 14] FIG. 14 is a schematic diagram of the valve assembly when used to depressurize fluid more rapidly compared to FIG. 13. [Figure 15] FIG. 15 is a perspective view of a valve assembly having the general configuration illustrated in FIGS. 7 to 14. [Figure 16] FIG. 15 is a perspective view of the valve assembly shown in FIG. 14 with various portions of the valve housing and valve case removed. [Figure 17] FIG. 16 is a cross-sectional view of the valve assembly shown in FIG. 15. [Figure 18] FIG. 16 is a cross-sectional view of the valve assembly shown in FIG. 15.

[0012] Corresponding reference characters indicate corresponding parts throughout the several views of these drawings. DETAILED DESCRIPTION OF THE INVENTION

[0013] Illustrative embodiments are more fully described hereinafter with reference to the accompanying drawings.

[0014] FIG. 1 schematically illustrates a valve assembly 10 according to the principles of the present disclosure. The valve assembly 10 includes a housing 12 having a fluid inlet port 14, a fluid outlet port 16, and a drain port 18. The valve assembly 10 includes a plurality of fill valves 20 in communication with the fluid inlet port 14 and the fluid outlet port 16. The valve assembly 10 also includes a plurality of discharge valves 22 in communication with the drain port 18. An internal flow path or second pressure path 21, which is a series of open flow paths within the housing 12, interconnects the fill valves 20, the discharge valves 22, and the outlet port 16. A controller 24 is in communication with a pressure sensor 26 and each of the fill valves 20 and the discharge valves 22 to dynamically control fluid flow through the valve assembly 10 and the fluid pressure at the outlet port 16 of the valve assembly 10. The pressure sensor 26 is in communication with the second flow path 21, which is in communication with the outlet port 16, and generates a signal indicative of the pressure within the second flow path 21 and the outlet port 16. In the exemplary embodiment shown, the valve assembly 10 is configured to pressurize and regulate the flow of air, however, it should be understood that the valve assembly 10 may be configured to pressurize and regulate any fluid known to those skilled in the art, including gases and liquids.

[0015] As best shown in FIG. 2 , controller 24 includes an input 23 configured to receive a voltage, current, or digital input (hereinafter, a “command signal”) from another controller or circuit 25 of a system (not shown) within which valve assembly 10 is used. For example, the system within which valve assembly 10 is used may be an actuator system. Typically, the command signal is a signal indicative of a desired pressure to be output from valve assembly 10 through outlet port 16. Input 23 may be configured to receive power from a power source (not shown) used to power controller 24 and valve assembly 10.

[0016] After receiving the command signal, input 23 transmits the command signal to signal discrimination circuit 27. Signal discrimination circuit 27 is configured to compare the command signal to a signal received from pressure sensor 26 indicative of the pressure at outlet orifice 16. As will be described in more detail below, based on a comparison of the command signal received by the controller with the periodic pressure signal output by pressure sensor 26, controller 24 is configured to dynamically control each of fill valve 20 and discharge valve 22 to control the pressure of fluid output from outlet orifice 16. Controller 24 may include a sensor compensation circuit 29 that receives the pressure signal from pressure sensor 26, compensates the pressure signal to a known sensor output relative to a known pressure reference, and then transmits the compensated signal to signal discrimination circuit 27, which compares the compensated signal with the command signal. It should also be understood that controller 24 may be configured to output a feedback signal to an operator of the system, which may be a voltage, current, or digital signal indicative of the pressure being output by valve assembly 10 or that the valve assembly 10 is outputting the pressure of the command signal.

[0017] 2 illustrates pressure sensor 26 as part of controller 24, it should be understood that pressure sensor 26 may be separate from controller 24, as shown in FIG. 1. Additionally, pressure sensor 26 may be any type of pressure sensor capable of generating a signal indicative of pressure. Specifically, the signal generated by pressure sensor 26 may be a voltage, a current, or a digital signal without departing from the scope of the present disclosure.

[0018] The fill valve 20 and the discharge valve 22 may each be a direct-acting solenoid valve, a solenoid pilot-operated valve, or any type of electrically operated valve known to those skilled in the art. To open and close the valves, the controller 24 may include an integrated valve driver circuit 28 configured to independently energize the fill valve 20 and the discharge valve 22 based on input from the signal discrimination circuit 27. Alternatively, the valve driver circuit 28 may be independent of and in communication with the controller 24. In either case, based on the pressure detected by the pressure sensor 26, the controller 24 instructs the valve driver circuit 28 to energize the fill valve 20 and / or the discharge valve 22, thereby opening the fill valve 20 and / or the discharge valve 22. To close the fill valve 20 and / or the discharge valve 22, the controller 24 instructs the valve driver circuit 28 to de-energize the fill valve 20 and / or the discharge valve 22.

[0019] In the illustrated embodiment, the fill valve 20 includes a high-flow fill valve 20a and a low-flow fill valve 20b. The high-flow fill valve 20a is generally configured to allow a larger flow rate of fluid than the low-flow fill valve 20b. To allow a larger flow rate of fluid through the high-flow fill valve 20a, the high-flow fill valve 20a may have a larger orifice size than the low-flow fill valve 20b, or the high-flow fill valve 20a may be larger than the low-flow fill valve 20b. Similarly, the discharge valve 22 includes a high-flow discharge valve 22a and a low-flow discharge valve 22b. The high-flow discharge valve 22a is generally configured to allow a larger flow rate of fluid than the low-flow discharge valve 22b. To allow a larger flow rate of fluid through the high-flow discharge valve 22a, the high-flow discharge valve 22a may have a larger orifice size than the low-flow discharge valve 22b, or the high-flow discharge valve 22a may be larger than the low-flow discharge valve 22b.

[0020] Figure 1 shows the configuration of valve assembly 10 when each fill valve 20 and each discharge valve 22 are closed (i.e., the pressure at outlet ports 16 is zero or the pressure at outlet ports 16 is the pressure indicated by the command signal). A method for pressurizing fluid and outputting the fluid at a higher pressure from valve assembly 10 will now be described with reference to Figures 3 to 6. Figure 3 shows the configuration when valve assembly 10 is energized, rapidly pressurizing valve assembly 10 and the fluid output from outlet ports 16.

[0021] Specifically, to rapidly pressurize valve assembly 10 from, for example, zero pressure to, for example, 30 psi, controller 24 instructs valve driver circuit 28 to apply voltage to both fill valves 20. When each fill valve 20 is energized, fluid flows from fluid inlet 14 through each fill valve 20 into second pressure path 21 and is available to be output from outlet 16. Pressure sensor 26 monitors the pressure at which fluid flows from fluid inlet 14 through each fill valve 20 into second pressure path 21 and is available to be output from outlet 16. When the pressure approaches a desired pressure (e.g., 30 psi), controller 24 instructs valve driver circuit 28 to de-energize high-flow fill valve 20a (FIG. 4). Because low-flow fill valve 20b remains energized, fluid can still flow from fluid inlet port 14 through low-flow fill valve 20b to outlet port 16, allowing valve assembly 10 to slowly reach the desired pressure (e.g., 30 psi) output from outlet port 16. In this manner, the possibility of overshoot (i.e., pressure greater than desired) is eliminated, or at least greatly reduced. When controller 24 receives a signal from pressure sensor 26 that the pressure at outlet port 16 has reached the desired pressure, controller 24 instructs valve driver circuit 28 to de-energize low-flow fill valve 20b.

[0022] After the fill valve 20 is de-energized, if the pressure at the outlet port 16, as sensed by the pressure sensor 26, overshoots (i.e., is greater than) the desired pressure (e.g., 30 psi), the controller 24 is configured to instruct the valve driver circuit 28 to energize the low-flow discharge valve 22b (FIG. 5), thereby allowing fluid to slowly exit the valve assembly 10 through the drain port 18. Because only the low-flow discharge valve 22b is energized, the pressure at the outlet port 16 is allowed to slowly decrease to the desired pressure. When the controller 24 receives a signal from the pressure sensor 26 that the pressure at the outlet port 16 has reached the desired pressure, the controller 24 instructs the valve driver circuit 28 to de-energize the low-flow discharge valve 22b. Alternatively, if pressure sensor 26 detects that use of low-flow discharge valve 22b has caused the pressure at outlet port 16 to drop below the desired pressure, controller 24 may instruct valve driver circuit 28 to re-energize low-flow fill valve 20a, allowing the pressure at outlet port 16 to gradually increase again to the desired pressure (FIG. 4).

[0023] 6 illustrates a situation in which it may be necessary to rapidly reduce the pressure at the outlet ports 16, for example, to zero pressure. In such a situation, the controller 24 may instruct the valve driver circuit 28 to energize each discharge valve 22 to rapidly exhaust fluid from the valve assembly 10 through each discharge valve 22 and the exhaust ports 18. While FIG. 6 illustrates each discharge valve 22 as being energized to rapidly reduce the pressure at the outlet ports 16, it should be understood that only the high flow discharge valve 22a may be used to reduce the pressure at the outlet ports 16.

[0024] 6 may be used to rapidly reduce the pressure at the outlet port 16 to zero, it should also be understood that the configuration of FIG. 6 may be used when the pressure at the outlet port 16 is relatively high (e.g., 30 psi) and the system incorporating the valve assembly 10 only requires fluid output at a significantly reduced pressure (e.g., 15 psi). In such a case, both discharge valves 22 or only the high-flow discharge valve 22a may be energized to rapidly reduce the pressure at the outlet port 16. While the pressure reduction is monitored by the pressure sensor 26, the high-flow discharge valve 22a may be de-energized to slow the pressure reduction to the target pressure (e.g., 15 psi), thereby allowing only the low-flow discharge valve 22b to discharge fluid from the valve assembly 10 through the exhaust port 18 (FIG. 5). If the pressure at the outlet port 16 sensed by the pressure sensor 26 undershoots (i.e., is less than) the target pressure (e.g., 15 psi), the low-flow discharge valve 22b may be de-energized and the low-flow fill valve 20b may be re-energized (FIG. 4) to allow the pressure at the outlet port 16 to reach the target pressure.

[0025] The above-described embodiments allow for dynamic control of pressure and fluid output from the valve assembly 10. In other words, by continuously detecting the pressure at the outlet port 16 using the pressure sensor 26, each fill valve 20 and discharge valve 22 can be controlled to increase, decrease, or maintain the pressure at the outlet port 16. Additionally, the use of the low-flow fill valve 20b and low-flow discharge valve 22b allows for more precise control of the pressure at the outlet port 16, significantly reducing overshooting or undershooting of the desired or target pressure. Additionally, if only small pressure changes at the outlet port 16 are desired, the low-flow fill valve 20b and / or low-flow discharge valve 22b can be used to reduce the desired pressure changes. Furthermore, it should be appreciated that the use of multiple fill valves 20 and discharge valves 22 allows the valve assembly 10 to remain operational, albeit with reduced performance, even if one of the fill valves 20 and / or discharge valves 22 fails.

[0026] 1 and 3-6 employ fill valve 20 and discharge valve 22 with one high-flow valve 20a and one low-flow valve 20b and one low-flow valve 22b in each valve set, but the present disclosure should not be limited in this regard. In this regard, fill valve 20 may include a greater number of high-flow fill valves 20a and / or low-flow fill valves 20b, and discharge valve 22 may include a greater number of high-flow discharge valves 22a and / or low-flow discharge valves 22b.

[0027] For example, in the embodiment shown with reference to Figures 7-14, the valve assembly 10 includes a plurality of fill valves 20, including a high flow fill valve 20a, a low flow fill valve 20b, a low flow fill valve 20c, and a minimum flow fill valve 20d. The valve assembly 10 also includes a high flow discharge valve 22a and a low flow discharge valve 22b. b and a plurality of discharge valves 22, including a high-flow discharge valve 22a and a low-flow discharge valve 22c. Any combination of fill valves 20 and any combination of discharge valves 22 are contemplated. For example, any of fill valves 20a-20d can be omitted in exchange for another high-flow discharge valve 20a, another low-flow discharge valve 20b, another low-low-flow fill valve 20c, or another minimum-flow fill valve 20d. Similarly, any of discharge valves 22a-22c can be omitted in exchange for another high-flow discharge valve 22a, another low-flow discharge valve 22b, or another low-low-flow fill valve 20c. In addition, it should be understood that discharge valve 22 may further include a minimum-flow discharge valve similar to minimum-flow fill valve 20d.

[0028] Similar to the embodiment shown in FIGS. 1 and 3-6, the valve assembly 10 shown in FIGS. 7-14 includes a housing 12 having a fluid inlet port 14, a fluid outlet port 16, a drain port 18, and a second pressure path 21. In addition, the valve assembly 10 includes a controller 24 similar to that shown in FIG. 2, and a pressure sensor 26. While the pressure sensor 26 is shown separate from the controller 24 in FIGS. 7-14, it should be understood that the pressure sensor 26 may be part of the controller 24, as shown in FIG. 2. In either case, based on the pressure detected by the pressure sensor 26, the controller 24 is configured to instruct the valve driver circuit 28 to independently apply voltages to the fill valve 20 and the discharge valve 22 to open or close the desired valve 20 and / or 22, thereby precisely controlling the pressure at which fluid can be output from the outlet port 16.

[0029] Additionally, although not required, the housing 12 may include a second exhaust port 30 that communicates only with the low-flow discharge valve 22c. The use of the second exhaust port 30 may be advantageous when the valve assembly 10 is used in applications where one or more actuators are pressurized and dirty or contaminated fluid (e.g., air) from the actuators may re-enter the valve assembly 10 through the bleed port 16 when the pressure is fully discharged to zero psi. In these cases, it is important to isolate the pressure sensor 26 from this dirty or contaminated fluid.

[0030] 7, when discharge valves 22a and 22b are not energized, any fluid re-entering valve assembly 10 through outlet port 16 is directed by discharge valves 22a and 22b directly to drain port 18. In this manner, pressure sensor 26 is isolated from dirty or contaminated fluid that may re-enter valve assembly 10 through outlet port 16. Furthermore, when low-low flow discharge valve 22 is not energized, low-low flow discharge valve 22c is in direct communication with second drain port 30, thereby allowing fluid in second pressure path 21 to exit valve assembly 10 through low-low flow discharge valve 22 and second drain port 30, completely reducing the pressure to zero psi. When the pressure in the second pressure path 21 drops to zero and the pressure sensor 26 determines that the risk of dirty or contaminated air re-entering the valve assembly 10 has been eliminated, the discharge valves 22a and 22b may be re-energized to reconnect the second pressure path 21 to the outlet hole 16 through each discharge valve 22a and 22b.

[0031] As can be seen in Figure 7, each fill valve 20 and each discharge valve 22 is de-energized, and the pressure at the outlet port 16 is zero psi, or a pressure corresponding to the command signal. At this point, each fill valve 20 is closed, and each discharge valve 22 is in communication with either the drain port 18 or the second drain port 30. The manner in which fluid is pressurized and output from the valve assembly 10 will now be described with reference to Figures 8-14. Figure 8 illustrates a configuration in which the valve assembly 10 is energized, causing the pressure at the outlet port 16 to rapidly increase.

[0032] Specifically, to rapidly increase the pressure at outlet port 16 from, for example, zero pressure to, for example, 30 psi, controller 24 instructs valve driver circuit 28 to energize fill valves 20a-20d and discharge valves 22a-22c. When fill valves 20a-20d are energized, fluid is permitted to flow from fluid inlet port 14 through fill valves 20a-20d and into valve assembly 10. Furthermore, when discharge valves 22a-22c are energized, discharge valves 22a and 22b are actuated to communicate with outlet port 16 rather than discharge port 18, and discharge valve 22c is actuated to not communicate with second discharge port 30.

[0033] Pressure sensor 26 monitors the pressure at outlet port 16. When the pressure approaches the desired pressure (e.g., 30 psi), controller 24 instructs valve driver circuit 28 to de-energize high-flow fill valve 20a (FIG. 9). Because the remaining fill valves 20b-20d remain energized, fluid can still flow from fluid inlet port 14 through fill valves 20b-20d to outlet port 16, allowing valve assembly 10 to reach the desired pressure (e.g., 30 psi) more slowly. As the pressure continues to approach the desired pressure, controller 24 instructs valve driver circuit 28 to de-energize low-flow fill valve 20b (FIG. 10). However, because the remaining fill valves 20c and 20d remain energized, fluid can still flow from fluid inlet port 14 through fill valves 20c and 20d to outlet port 16, allowing valve assembly 10 to reach the desired pressure more slowly. As the pressure continues to approach the desired pressure, controller 24 instructs valve driver circuit 28 to de-energize low-flow fill valve 20c (FIG. 11). However, because the remaining fill valve 20d remains energized, fluid can still flow from fluid inlet port 14 through fill valve 20d and out outlet port 16, allowing valve assembly 10 to reach the desired pressure more slowly. Then, as the pressure finally approaches the desired pressure, controller 24 instructs valve driver circuit 28 to de-energize minimum-flow fill valve 20d (FIG. 12). In this way, the possibility of overshoot (i.e., the pressure becoming greater than the desired pressure) is eliminated, or at least significantly reduced.

[0034] On the other hand, if the pressure at the outlet port 16, as sensed by the pressure sensor 26, overshoots (i.e., is greater than) the desired pressure (e.g., 30 psi), the controller 24 may instruct the valve driver circuit 28 to de-energize the low-low flow discharge valve 22c (FIG. 13), thereby allowing fluid to slowly exit the valve assembly 10 through the second exhaust port 30. With only the low-low flow discharge valve 22c de-energized, the pressure at the outlet port 16 is allowed to slowly drop to the desired pressure. When the controller 24 receives a signal from the pressure sensor 26 that the pressure at the outlet port 16 has reached the desired pressure, the controller 24 instructs the valve driver circuit 28 to energize the low-low flow discharge valve 22c (FIG. 12). Alternatively, if pressure sensor 26 detects that the pressure at outlet port 16 has dropped below the desired pressure due to use of low-low flow discharge valve 22c, controller 24 may instruct valve driver circuit 28 to re-energize minimum flow fill valve 20d to gradually increase the pressure at outlet port 16 back to the desired pressure (FIG. 11).

[0035] 12 illustrates a situation where it is necessary to rapidly reduce the pressure at the outlet port 16. In such a situation, the controller 24 instructs the valve driver circuit 28 to Filling valve 20a-20d De-energize the valves and release the fluid. 22a and 22b to outflow hole 16 1. The valve assembly 10 may be rapidly vented through the stomach. Although FIG. 14 shows only discharge valves 22b and 22c as being de-energized to rapidly reduce the pressure at outlet port 16, it should be understood that all discharge valves 22a-22c may be de-energized to reduce the pressure at outlet port 16 without departing from the scope of the present disclosure.

[0036] 14 may be used to rapidly reduce the pressure at the outlet port 16, it should also be understood that the configuration of FIG. 14 may be used when the pressure at the outlet port 16 is relatively high (e.g., 30 psi) and the system incorporating the valve assembly 10 only requires a significantly reduced pressure (e.g., 15 psi). In such a case, the discharge valves 22b and 22c or only the low-flow discharge valve 22b may be de-energized to gradually reduce the pressure at the outlet port 16. While the pressure drop is monitored by the pressure sensor 26, the low-flow discharge valve 22b may be energized to slow the pressure drop to the target pressure (e.g., 15 psi), thereby allowing only the low-flow discharge valve 22c to discharge fluid from the valve assembly 10 through the second exhaust port 30 (FIG. 13). If the pressure at the outlet port 16 detected by the pressure sensor 26 undershoots (i.e., is less than) the target pressure (e.g., 15 psi), the low-low flow discharge valve 22b may be energized and the minimum flow fill valve 20d may be re-energized (FIG. 11) to allow the pressure to reach the target pressure.

[0037] According to the above-described embodiment, the pressure and fluid output from the valve assembly 10 can be dynamically controlled. In other words, by continuously detecting the pressure at the outlet port 16 using the pressure sensor 26, each fill valve 20 and discharge valve 22 can be controlled to increase, decrease, or maintain the pressure output from the outlet port 16. Additionally, the use of fill valves 20b-20d and discharge valves 22b and 22c allows for more precise control of the pressure output from the outlet port 16, significantly reducing overshooting or undershooting of the desired or target pressure. Additionally, if only a small pressure change is required, the fill valves 20b-20d and discharge valves 22b and 22c can be used to achieve this desired small pressure change. Furthermore, it should be appreciated that by using multiple fill valves 20 and discharge valves 22, the valve assembly 10 can still operate, albeit with reduced performance, even if one of the fill valves 20 and / or discharge valves 22 fails.

[0038] It should be understood that in each of the above-described embodiments, the controller 24 may include custom software configured to operate the plurality of fill valves 20 and the plurality of discharge valves 22 such that the performance characteristics of the valve assembly 10 can be customized for each particular application in which the valve assembly 10 is used. This software may have built-in read / write functionality, providing the ability to learn and make changes based on the characteristics of a particular application, thereby enabling optimal performance of the valve assembly in a particular application.

[0039] More specifically, by having read / write capabilities, the software can learn various parameters required for a particular application, such as the working volume of fluid to be output, any leakage, the speed at which fluid output is desired, the breakaway forces required to drive the actuator, and the friction characteristics of the actuator, in order to optimize the time required to reach the desired pressure and reduce overshoot and undershoot. The software may be able to monitor changes in the working volume, thereby enabling it to continually optimize the operation of the valve assembly 10 for each commanded target pressure.

[0040] An exemplary valve assembly 10 incorporating the valve circuit shown in FIGS. 7 to 14 will now be described with reference to FIGS. 15 to 18. The valve assembly 10 includes a housing 12, an inlet port 14, an outlet port 16, an outlet port 18, a second pressure path 21, and a second outlet port 30. As best shown in FIG. 16, the valve assembly 10 also includes fill valves 20a to 20d, discharge valves 22a to 22c, and a controller 24. In FIG. 16, the case 32 that attaches the fill valves 20a and 20b and the discharge valves 22a and 22b to the housing 12 via bolts 34 has been removed to clearly show the structures of the fill valves 20a, 20b and the discharge valves 22a, 22b. The fill valves 20a, 20b and the discharge valves 22a, 22b are solenoid pilot-operated valves driven by a pilot 36.

[0041] Fill valves 20a and 20b each include a piston 38 that forms a pair of valve members 40. The case 32 of fill valves 20a and 20b defines a valve bore 42 that includes a valve seat 44a for the valve member 40 (FIGS. 17 and 18). When piston 38 is actuated by pilot 36, valve member 40 moves away from valve seat 44a, allowing flow through fill valves 20a, 20b and pressurizing valve assembly 10.

[0042] Each discharge valve 22a and 22b also includes a piston 38 that defines a pair of valve members 40a and 40b. The cases 32 of the discharge valves 22a and 22b define a valve bore 42 that includes a pair of valve seats 44b and 44c for the valve members 40a and 40b, respectively. As described above, each discharge valve 22a and 22b communicates with the drain port 18 when de-energized and connects the second pressure path 21 to the outlet port 16 when energized, and thus each discharge valve 22a and 22b includes a pair of valve members 40a, 40b and a pair of valve seats 44b, 44c. When the piston 38 is actuated by the pilot 36 (i.e., energized), the valve member 40b moves away from the valve seat 44c, and the valve member 40c engages the valve seat 44b, obstructing flow to the drain port 18 and allowing flow through the discharge valves 22a and 22b to pressurize the outlet port 16.

[0043] Fill valves 20c, 20d and discharge valve 22c are solenoid-operated valves. Each fill valve 20c, 20d and discharge valve 22c includes a valve stem 46 forming a valve member 48 disposed within a valve bore 50 formed within housing 12. Valve bore 50 communicates with passages (not shown) communicating with inlet port 14 and outlet port 16 in the case of fill valves 20c, 20d. Valve bore 50 of discharge valve 22c communicates with second pressure path 21 and second exhaust port 30. When each fill valve 20c, 20d is energized, valve member 48 opens inlet port 14, allowing communication between second pressure path 21 and outlet port 16. When discharge valve 22c is energized, it is closed.

[0044] The above description of the embodiments is provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are not limited to that particular embodiment broadly, but where applicable, are interchangeable and may be used in selected embodiments even if not specifically shown or described. The same may be modified in many ways. Such modifications should not be considered a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

Claims

1. 1. A valve assembly comprising: a housing having a fluid inlet hole, a fluid outlet hole, a discharge hole, and a second discharge hole; a plurality of first discharge valves respectively communicating with the discharge hole and the fluid outflow hole; a plurality of filling valves respectively communicating with the fluid inlet, each of the first discharge valves, and the fluid outlet; a second discharge valve communicating with the filling valve and the second discharge hole; a pressure sensor configured to generate a signal indicative of a fluid pressure within the enclosure; a controller configured to selectively open and close each of the fill valves, each of the first discharge valves, and each of the second discharge valves based on a received command signal including a desired pressure to be output from the fluid outlet holes and compared with a signal indicative of the fluid pressure; the controller is configured to selectively open and close the plurality of fill valves, the plurality of first discharge valves, and the second discharge valve to pressurize and output fluid at the desired pressure from the valve assembly until the desired pressure is reached; When the desired pressure is reached, the fluid can flow through the fluid inlet port, through a selected, open portion of the fill valve, and then through a selected, open portion of the first discharge valve to the fluid outlet port; A valve assembly, characterized in that, when the plurality of first discharge valves are closed, fluid can flow from the fluid outlet hole through each of the plurality of first discharge valves to the drain hole.

2. 2. The valve assembly of claim 1, wherein the controller is configured to close the fill valve and selectively open and close multiple of the first release valves to allow the fluid to exit the valve assembly through the fluid outlet holes to reduce the pressure of the fluid output from the fluid outlet holes.

3. 2. The valve assembly of claim 1, wherein the plurality of fill valves and the plurality of first discharge valves are open and the second discharge valve is closed during pressurization of the fluid.

4. 4. The valve assembly of claim 3, wherein as the fluid approaches the desired pressure, the controller is configured to close a portion of the fill valve and maintain a portion of the fill valve in an open position until the desired pressure is reached.

5. 5. The valve assembly of claim 4, wherein once the fluid is pressurized to the desired pressure, if the pressure sensor generates a signal indicating that the fluid pressure is greater than the desired pressure, the controller is configured to open the second release valve to reduce the fluid pressure through the second outlet port until the desired pressure is reached.

6. 2. The valve assembly of claim 1, wherein the controller includes a valve driver circuit in communication with each of the fill valves, each of the first release valves, and each of the second release valves, the valve driver circuit configured to apply a voltage to each of the fill valves, each of the first release valves, and each of the second release valves to selectively open and close each of the fill valves, each of the first release valves, and each of the second release valves.

7. 7. The valve assembly of claim 6, wherein each of the fill valves, each of the first discharge valves, and each of the second discharge valves is either a solenoid operated valve or a pilot operated solenoid valve.

8. 2. The valve assembly according to claim 1, wherein the plurality of filling valves comprises at least a first filling valve and a second filling valve, and the first filling valve allows a larger amount of fluid to flow than the second filling valve.

9. 9. The valve assembly of claim 8, wherein the controller is configured to first close the first fill valve before closing the second fill valve as the fluid approaches the desired pressure.

10. 2. The valve assembly according to claim 1, wherein the plurality of first discharge valves comprises at least a high-flow discharge valve and a low-flow discharge valve, the high-flow discharge valve allowing a larger amount of fluid to flow than the low-flow discharge valve.

11. 11. The valve assembly of claim 10, wherein once the fluid is pressurized to the desired pressure, if the pressure sensor generates a signal indicating that the fluid pressure is greater than the desired pressure, the controller is configured to close the fill valve and open at least the low flow discharge valve to reduce the fluid pressure until the desired pressure is reached.

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