Variable pressure regulating valve

Abstract

The present disclosure relates to a valve assembly (10) for controlling flow. The valve body (12) has an inlet end (14) and an outlet end (16). A piston (24) is positioned within the valve body (12) and is movable between an open position for opening the valve body (12) and a closed position for closing the valve body (12). A spring (26) is mounted between the piston (24) and a spring adjusting member (26). A portion of the spring adjusting member is accessible through the inlet end (14) of the valve body (12) such that it can be engaged by a tool to facilitate rotation of the spring adjusting member to vary the compression of the spring (26) to adjust a pressure regime of the spring (26). Figure for abstract: figure4

Description

Title of the invention: Variable pressure regulating valve Technical field

[0001] The present disclosure relates generally to a system and method for controlling pressure conditions during fuel tank operations, specifically to pressure-operated control valves that respond to fuel pressure.

[0002] BACKGROUND

[0003] Various systems and devices are used to control back pressure when filling aircraft fuel tanks. Aircraft are adapted for in-flight refueling and have a fuel conduit or manifold that can lead to a number of separate fuel tanks.

[0004] In refueling operations, a service vehicle is connected to a refueling hose to pump fuel into the fuel tanks of an aircraft. During the connection, there may be fuel pressure in the fuel line. This fuel pressure is monitored and controlled by end-of-pipe regulator valves (HECVs). The end-of-pipe regulator valves provide pressure limitation at an outlet to protect aircraft from over-pressurization and surge during refueling. The end-of-pipe regulator valves admit fuel into the fuel tank when they open and they automatically close in response to increased back pressure in the fuel manifold or line when the fuel tank is full.

[0005] End-of-pipe control valves are capable of operating at multiple pressure regimes. As a result, customers can choose from various pressure settings to tailor control systems to their requirements. These pressure settings are important to avoid damage to fuel tanks or dangerously high surges in the fuel line.

[0006] Typically, to change the pressure settings of an HECV, the customer would have to disassemble the HECV in order to replace a spring inside the HECV chamber with a different spring that has a load requirement to achieve a different pressure setting. This can be time consuming and inefficient.

[0007] Thus, there is a need for a variable end-of-pipe regulating valve, whereby various pressure adjustments can be achieved simply and quickly without disassembling the end-of-pipe regulating valve.

[0008] SUMMARY

[0009] The present disclosure relates to variable end-of-pipe control valves (HECVs) that provide pressure limitation to protect an aircraft during refueling. The variable HECV is a unique device that can provide different pressure settings to accommodate a customer's control system without having to disassemble the HECV to replace an internal spring that achieves a different pressure setting. That is, unlike traditional HECVs that require the use of multiple springs to achieve different pressure regimes, the variable HECV has a compensator that can vary the compression of a single spring allowing adjustment of the spring within the variable HECV to achieve the desired pressure regime without disassembling the variable HECV.

[0010] One aspect of the present disclosure relates to a valve assembly for controlling fluid flow. The valve assembly includes a valve body having an inlet end and an outlet end. The valve body defines a chamber and a piston is positioned within the chamber and is movable between an open position for opening the valve body and a closed position for closing the valve body. A spring is mounted (e.g., captured) between the piston and a spring adjuster and operates to bias the piston toward an open position. A portion of the spring adjuster is accessible from the inlet end of the valve body so as to be engageable by a tool to facilitate rotation of the spring adjuster to vary spring compression to adjust a spring pressure regime.In some examples, back pressure from the outlet end acts on the piston against spring bias to move the piston to a closed position when the back pressure exceeds a pressure threshold set by a spring load setting.

[0011] Another aspect of the present invention relates to a valve assembly for controlling flow from a pressurized source to a reservoir. The valve assembly includes a valve body having an inlet end and an outlet end. The valve body defines fluid passages for receiving fluid flow between the inlet and outlet ends. A piston is mounted within the valve body for controlling the fluid flow. The piston is movable between an open position and a closed position. A cap member mounts to the inlet end of the valve body.

[0012] A compensating device is housed within the cap member. The cap member mounts the compensating device within the valve body. The compensating device is accessible from the inlet end of the valve.

[0013] A spring is located between the piston and the compensating device. The spring biases the piston toward the open position and the spring is compressed when the piston moves toward the closed position. One end of the spring may be received within the cap. The compensating device is configured to rotate axially relative to the cap to vary the compression of the spring to achieve a desired spring pressure. In one example, the compensating device is coupled to the cap by a threaded connection. In one example, the cap may cap one end of a spring chamber (e.g., a centrally located passage in which the spring, cap, and piston are at least partially positioned) adjacent the inlet end of the valve.

[0014] Another aspect of the present disclosure relates to a valve assembly for controlling the flow of liquid from a pressurized supply into a reservoir. The valve assembly includes a valve body having an inlet end and an opposing outlet end. A piston operates to close the valve assembly in response to a rise in fluid back pressure when a predetermined liquid level is reached in the reservoir. A spring is mounted (e.g., captured) between the piston and a spring adjustment member. A portion of the spring adjustment member is accessible from the inlet end of the valve body such that it can be engaged by a tool to facilitate axial movement of the spring adjustment member to vary the compression of the spring to achieve a spring pressure regime.

[0015] These and other features and advantages will become apparent from the following detailed description and an examination of the associated drawings. Various additional aspects will be indicated in the following description. The aspects may relate to individual features and combinations of features. It is understood that the foregoing general description and the following detailed description are provided by way of example and explanation only and are not limiting of the broad concepts upon which the examples disclosed herein are based. Brief description of the drawings

[0016] The accompanying drawings, which are incorporated in and form a part of the specification, illustrate several aspects of the present disclosure. A brief description of the drawings is as follows:

[0017] [Fig. 1] is a perspective view showing an outlet end of a variable pressure regulating valve in accordance with the principles of the present disclosure.

[0018] [Fig.2] is a perspective view showing an inlet end of the variable pressure regulating valve of [Fig.l].

[0019] [Fig.3] is an outlet end view of the variable pressure regulating valve of [Fig.l].

[0020] [Fig.4] is a cross-sectional view taken along line 4 - 4 of the [Fig.3].

[0021] [Fig.4A] is a cross-sectional view of the variable pressure regulating valve of [Fig.4] with a compensator set to a first pressure setting position and the variable pressure regulating valve in the open position.

[0022] [Fig.4B] is a cross-sectional view of the variable pressure regulating valve of [Fig.4] with the compensator set to the first pressure setting position and the variable pressure regulating valve in the closed position.

[0025] [Fig.5] is an enlarged view of a portion of [Fig.4].

[0023] [Fig.6] is a perspective view showing an inlet end view of a cap and a compensating device according to the principles of this disclosure.

[0024] [Fig.7] is a perspective view showing an outlet end view of the hood and the compensating device of [Fig.6].

[0025] [Fig.8] illustrates an exploded view showing the compensating device of [Fig.6] and 7 burst from the cap.

[0026] [Fig.9] illustrates the compensating device of [Fig.6] and 7 from the perspective of the inlet end of the valve.

[0027] [Fig. 10] illustrates the compensating device of [Fig.6] and 7 from the perspective from the outlet end of the valve.

[0028] [Fig. 11] is a cross-sectional view of the pressure regulating valve variable of [Fig.4] showing the valve in the open position with the compensator set to a second pressure setting position.

[0029] [Fig. 12] is a cross-sectional view of the pressure regulating valve variable of [Fig.4] showing the valve in the closed position with the compensator set to the second pressure setting position.

[0030] [Fig. 13] is a perspective view of another example of a regulating valve of variable pressure in accordance with the principles of the present invention, the example includes two housing parts.

[0031] [Fig. 14] is an exploded view of the variable pressure regulating valve of the [Fig.13],

[0032] [Fig. 15] is a cross-sectional view of the pressure regulating valve variable of [Fig.13] showing a cap, a compensating device, a spring and a piston in accordance with the principles of the present disclosure.

[0033] [Fig. 16] is an enlarged view of a portion of [Fig. 15].

[0034] [Fig. 17] is an exploded view showing the cap and the compensating device of [Fig. 15],

[0035] Figures 18 to 19 are perspective views illustrating the compensating device of [Fig. 15] mounted within the cap.

[0036] [Fig. 20] is a cross-sectional view of the variable pressure regulating valve of [Fig. 15] showing the piston in an open position and the compensator in a first pressure setting position.

[0037] [Fig.21] is a cross-sectional view of the variable pressure regulating valve of [Fig.20] showing the piston in the closed position and the compensator at a first pressure setting position.

[0038] [Fig. 22] is a cross-sectional view of the variable pressure regulating valve of [Fig. 15] showing the piston in the open position and the compensating device axially displaced to a second pressure setting position to further compress the spring.

[0039] [Fig.23] is a cross-sectional view of the variable pressure regulating valve of [Fig.22] showing the piston in the closed position and the compensating device axially displaced to the second pressure setting position. DETAILED DESCRIPTION

[0040] The present disclosure relates to a variable pressure control valve adapted to respond to changes in outlet pressure to protect an aircraft during refueling. The pressure limitation is a function of a spring housed in the variable pressure control valve which loads a piston (e.g., a sliding member that can be driven by pressure) to limit the pressure sensed at the outlet of the variable pressure control valve.

[0041] The advantageous feature of the variable pressure control valve according to the present invention is to provide a variety of pressure regimes suitable for refueling fuel receiving tanks such as those mounted in aircraft. The variable pressure control valve eliminates the need for disassembly to replace one spring with another to achieve a different pressure setting. Thus, there is no need to provide multiple springs or valves to adapt control systems to a customer's requirements. Rather, the variable pressure control valve of the present invention includes a spring adjuster for changing the compression of a single spring to achieve varied pressure regimes without disassembling the variable pressure control valve.

[0042] Figures 1-3 illustrate a variable pressure regulating valve 10 (e.g., a pressure regulating valve or an end-of-pipe regulating valve) in accordance with the principles of the present disclosure. The variable pressure regulating valve 10 includes a valve body 12 with an end 14 inlet and an opposite outlet end 16. The valve body 12 is preferably formed of cast metal, such as aluminum. In the example shown, the valve body 12 is a single housing, although variations are possible. In other examples, the pressure regulating valve 10 may include two separate housing pieces (see [Fig. 13]).

[0043] The valve body 12 defines a fluid passage arrangement 18 with fluid passages 20 (see [Fig. 4]) for receiving fluid flow between the inlet and outlet ends 14, 16. The fluid passages 20 extend around a central region of the valve body as the passages 20 extend between the inlet and outlet ends 14, 16. The inlet end 14 of the valve body 12 is provided with a flange structure 22 for coupling with a fuel tank supply hose (not shown). A variety of inlet fittings (e.g., threaded fittings) or quick disconnect adapters are available for coupling industry standard hose fittings to the inlet end 14 of the valve body 12.

[0044] A nozzle (not shown), such as Eaton® Carter® product line nozzle models 64348, 64200, 64201, or 64349, may be coupled to the outlet end 16 of the valve body 12 to interface directly under the wing of an aircraft for refueling. A variety of threaded outlet adapter fittings may also be available for alternative installations away from a nozzle.

[0045] The variable pressure regulating valve 10 includes a piston 24 visible through the outlet end 16 of the valve body 12. The piston 24 is slidably mounted in the valve body 12 between an open position (see [Fig. 4A]) and a closed position (see [Fig. 4B]). The piston 24 is configured to limit the pressure sensed at the outlet end 16 of the valve body 12 or at the inlet of a nozzle on which the variable pressure regulating valve 10 is mounted. That is, the piston 24 is configured to respond to changes in outlet pressure or aircraft-side back pressure to close the valve if the back pressure reaches a predetermined level / limit during refueling, the predetermined level / limit being set by an amount of compression of a spring of the valve. The amount of compression of the spring may be adjusted via a compensator of the valve.

[0046] When refueling a stationary aircraft, pressurized fuel from a fuel source is allowed to pass through a hose and the variable pressure regulating valve 10 connected thereto. Then, the fuel passes through a line and a nozzle at the opening of the variable pressure regulating valve 10 to enter fuel tanks mounted under the wings of the aircraft. The aircraft fuel tanks may be filled with fuel, after which the piston 24 of the variable pressure regulating valve 10 moves toward the closed position to prevent further delivery of fuel into the fuel line. This is because, as the fuel tanks are filled to a desired level, the fuel pressure in the line may rise so that the fuel will be forced to surge and the position of the piston 24 will be moved to the closed position so as to cut off the flow of fuel. When the fuel pressure is again equalized, the piston 24 can be opened in preparation for another refueling operation. The open position being the default state of the variable pressure regulating valve 10.

[0047] The variable pressure control valve 10 helps maintain a desirable fuel flow rate at a predetermined constant pressure. A typical pressure range may be 241 to 345 kilopascals (kPa). The variable pressure control valve 10 is adapted to control the pressure when the downstream fuel pressure or back pressure falls within its control range.

[0048] Referring to Figures 4, 4A, 4B, cross-sectional views of the variable pressure control valve 10 are shown. The variable pressure control valve 10 is configured to limit pressure in accordance with a spring 26 mounted in the valve body 12. In some examples, the spring 26 may be a compression coil spring that compresses upon application of a load. The spring 26 loads the piston 24 of the variable pressure control valve 10. A biasing force on the piston 24 is provided by the spring 26 which biases the piston 24 toward its open position. Changes in back pressure during refueling may bias the piston 24 toward its closed position in opposition to the spring 26.Indeed, the piston 24 is operative to close the variable pressure control valve 10 in response to a rise in fluid back pressure when a predetermined liquid level is reached in the reservoir.

[0049] The piston 24 may include a head portion 28 and a shaft portion 30. The variable pressure control valve 10 may include a stationary sleeve 32 bolted within the valve body 12 via fasteners 34 to support the shaft portion 30 of the piston 24. When back pressure from the aircraft comes under the control of the variable pressure control valve 10, the piston 24 may be biased toward the closed position so that the head portion 28 moves down and obstructs a shoulder 36 of the valve body 12. Once sealed, the piston 24 closes the fluid passages 20 to stop the flow of fuel. The shoulder 36 may include circumferential grooves 38 to receive O-ring type sealing elements 40 or other suitable sealing mechanism. The O-ring sealing elements 40 may be made of Teflon or the like, a well-known material with a low coefficient of friction.As shown in [Fig.5], the piston 24 is supported relative to the valve body 12 by means of a spring ring. split annular 42 (e.g., a bearing which also provides sealing and may include an annular seal) and is limited in its sliding movement by a piston ring 44.

[0050] A hollow plug or cap 46 may be positioned within the valve body 12 adjacent the inlet end 14. A central spring passage (e.g., a spring cavity 92) is defined within the valve body 12 and is sealed relative to the passage device 18. One end of the central spring passage adjacent the inlet end 14 of the valve body 12 is closed by the cap 46. In some examples, the cap 46 may be threadably connected to the valve body 12, although variations are possible. In other examples, the cap 46 may be connected to the valve body 12 via a quick-disconnect assembly such as a snap ring.

[0051] Referring to Figures 6-7, the cap 46 includes a main body 48 and an extension portion 50 extending from the main body 48. The extension portion 50 of the cap 46 defines a cylindrical recess 52. In some examples, when the cap 46 is connected to the valve body 12 and the piston 24 is in the closed position, the recess 52 may receive the shaft portion 30 of the piston 24 and may function as a piston guide or cylinder. In other examples, a shaft portion of a piston may not engage or contact a cap mounted in the valve body. For example, the piston 24a shown in [Fig. 23] does not engage or contact any portion of the cap 46a when the spring 26a is in a state of maximum compression. One end of the spring 26 may be contained in the recess 52.

[0052] The extension portion 50 may be provided with external threads 54 that threadably engage internal threads of the valve body 12 to provide a threaded connection 56 (see [Fig. 4]). For example, internal threads of the valve body 12 may be adjacent the inlet end 14 to receive the extension portion 50 of the cap 46 to threadably engage the external threads 54 thereof.

[0053] The main body 48 of the cap 46 has an external key interface 59 such as flats for applying torque to the cap 46 upon connection to the valve body 12. Once the cap 46 is fully secured within the valve body 12, the main body 48 of the cap 46 may be disposed flush with a shoulder 58 (see [Fig.4]) of the valve body 12.

[0054] Returning to Figures 8-10, the variable pressure regulating valve 10 includes a compensating device 60 (e.g., an adjusting nut, a spring adjusting member) that can be mounted within the recess 52 of the cap 46. The compensating device 60 is generally T-shaped with a head portion 62 and a shank portion 64. The head portion 62 may be rounded, as shown. The compensating device 60 may be secured within the cap 46 via a threaded connection 66 (see [Fig. 4]). The head portion 62 may have fine pitch threads 68 formed on an outer surface 70 thereof to facilitate precision axial movement of the compensating device 60 within the cap 46. In effect, the fine pitch threads 68 allow the compensating device 60 to be adjusted gradually or in small increments relative to the cap 46. The fine pitch threads 68 of the compensating device 60 threadedly engage internal threads 72 (see [Fig. 7]) formed in the cap 46 to provide the threaded connection 66.

[0055] The main body 48 of the cap 46 defines an opening 74 for receiving the stem portion 64 of the compensator device 60. Thus, the stem portion 64 extends through the main body 48 and may be accessible at the inlet end 14 of the valve body 12 when the adapter / fitting is removed from the variable pressure regulating valve 10. A seal may be provided between the stem portion 64 and the cap 46 at the opening 74 to provide a seal between the cap 46 and the stem portion 64.

[0056] Referring again to [Fig. 4A], the spring 26 is shown with a minimal load (e.g., zero load) applied thereto. Indeed, the head portion 62 of the compensator device 60 can be lowered within the cap 46 to be positioned flush therewith such that zero load is applied to the spring 26. When the compensator device 60 is in this position away from the cap 46, the spring has a compression ratio of 241 kPa. When it is desired to change the spring pressure to a higher value, the compensator device 60 can be axially adjusted to apply a load to the spring 26 to meet customer control pressure requirements. Of course, depending on the application, springs having other ranges of pressure regimes could also be used.

[0057] Referring to Figures 11-12, the spring 26 is biased between the compensator device 60 and the piston 24. The compensator device 60 is designed to control the pressurization of the spring 26 by axially changing the position of the compensator device 60 within the cap 46. Indeed, the compensator device 60 can be rotated clockwise or counterclockwise, about a central axis X relative to the cap 46 to move axially from the lowered position shown in [Fig.4A] to compress the spring 26 to meet required pressure regimes. Thus, the compensator device 60 eliminates the need to have separate springs with different pressure regimes for various applications. With the compensator device 60, a single spring 26 can be used to achieve different pressure regimes. Thus, the variable pressure regulating valve 10 can be used with various applications without disassembly.

[0058] The stem portion 64 of the compensator device 60 may include a visual indicator 76 at a distal end 78 thereof. In some examples, the visual indicator 76 includes a plurality of indicator grooves 76a, 76b, 76c defined circumferentially on the stem portion 64 of the compensator device 60 to indicate a specific pressure setting, although variations are possible. For example, the indicator grooves 76a-c may represent pressure regimes of 310, 331, and 345 kPa, respectively.

[0059] The stem portion 64 defines a torque transmitting feature 80 such as a hexagonal feature adjacent the visual indicator 76 for rotating the compensator device 60. The torque transmitting element 80 of the compensator device 60 may be accessible through the inlet end 14 of the valve body 12 once an operator removes a pipe fitting or adapter mounted on the variable pressure regulating valve 10. Once the pipe adapter / fitting is removed from the inlet end 14 of the variable pressure regulating valve 10, an operator may take a tool, such as a screwdriver, wrench, or Allen key, and insert it into the torque transmitting element 80 of the stem portion 64 to threadably adjust the compensator device 60 axially.The compensator device 60 may be rotated or rotated clockwise or counterclockwise about the central axis X to make fine adjustments relative to the cap 46 to set the spring 26 to a desired pressure regime. Rotating the compensator device 60 to the left or right may either decrease the gap between the compensator device 60 and the piston 24, so that the spring 26 is smaller (i.e., tight, compressed) or increase the gap between the compensator device 60 and the piston 24 so that the spring 26 is larger (i.e., looser).

[0060] The compensator device 60 can be rotated until the desired indicator groove 76a-c is flush with an outer surface 82 of the cap 46 to set the spring pressure rate to either 310, 331, or 345 kPa. The variable pressure regulating valve 10 can be adjusted in the field to achieve the desired spring pressure rate. For example, to set the variable pressure regulating valve 10 to 310 kPa, the compensator device 60 can be adjusted from the position shown in [Fig.4A] to a position in which the indicator groove 76a is flush with the outer surface 82 of the cap 46 to set the spring 26 to a compression rate of 310 kPa.

[0061] To adjust the variable pressure regulating valve 10 to 331 kPa, the compensating device 60 is adjusted by turning the Allen key in the transmission element of torque 80 clockwise to axially move the compensating device 60 relative to the cap 46 until the indicator groove 76b is flush with the outer surface 82 of the cap 46 to set the spring 26 with a compression rate of 331 kPa.

[0062] To set the variable pressure regulating valve 10 to 345 kPa, the compensator device 60 continues to be adjusted axially about the central axis X until the indicator groove 76c is flush with the outer surface 82 of the cap 46 to set the spring 26 to a compression rate of 345 kPa as shown in [Fig. 11]. [Fig. 12] shows the spring 26 at its maximum compression value of 345 kPa with the piston 24 in the closed position. When a maximum load (i.e., a compression rate of 345 kPa) is applied to the spring 26, the head of the compensator device 60 is generally centered within the cap 46. Figures 4A and 4B show the spring 26 at its minimum compression value 241 kPa. One end of the spring 26 may be contained within the cap 46 while the opposite end of the spring 26 may be contained within the shaft portion 30 of the piston 24.

[0063] Teflon™ washers 84 may be positioned at opposite ends 86, 88 of the spring 26 to eliminate any friction or torsional influence on the compensator device 60 during operation. The overall length of the spring 26 between the compensator device 60 and the piston 24 or spring cavity 92 may be manipulated as illustrated in Figures 11 and 12 to achieve a desired pressure regime without torsional influence.

[0064] The variable pressure regulating valve 10 may also include a vent plug 90 which is typically used during fuel unloading operations. For example, the vent plug 90 allows the piston 24 to be blocked so that fuel can flow from the outlet end 16 to the inlet end 14.

[0065] Figures 13-23 show another example of a variable pressure regulating valve 10a according to the principles of the present invention. The variable pressure regulating valve 10a has the same features as the variable pressure regulating valve 10 of Figures 1-12 except that it includes a two-part valve body. Thus, like reference numerals will be used to describe like elements.

[0066] Referring to [Fig. 14], the variable pressure regulating valve 10a includes a first valve housing piece 12a and a second housing piece 12b. The first and second valve housing pieces 12a, 12b are connected to each other via fasteners 102. The first and second valve housing pieces 12a, 12b may be machined. The valve 10a has a more elongated configuration between opposed inlet and outlet ends 14a, 16a. relative to the valve 10. The passages 20a extend between the inlet and outlet ends 14a, 16a.

[0067] The variable pressure regulating valve 10a includes a piston 24a, a spring 26a, a cap 46a that mounts a compensator device 60a within the variable pressure regulating valve 10a as shown in [Fig. 15]. Compared to the compensator device 60, the compensator device 60a has a longer stem 64a and the cap 46a has a longer extension portion 50a to accommodate a greater range of movement of the compensator device 60a relative to the cap 46a. In addition, the spring 26a is longer than the spring 26. The variable pressure regulating valve 10a is configured to operate analogously to the variable pressure regulating valve 10 of Figures 1-12. Thus, the characteristics of the piston 24a, the spring 26a, the cap 46a and the compensating device 60a will not be repeated for the sake of brevity.

[0068] The principles, techniques, and features described herein may be applied in a variety of systems, and there is no requirement that all of the identified advantageous features be incorporated into an assembly, system, or component to achieve a certain advantage according to the present disclosure.

[0069] From the foregoing detailed description, it will be appreciated that modifications and variations may be made to aspects of the invention without departing from the spirit or scope of the disclosure.

Claims

1. Claims A valve assembly (10) for controlling flow from a pressurized source to a reservoir, the valve assembly (10) comprising: a valve body (12) having an inlet end (14) and an outlet end (16), the valve body (12) defining fluid passages (20) for receiving fluid flow between the inlet (14) and outlet (16) ends; a piston (24) mounted within the valve body (12) for controlling the flow of fluid, the piston (24) being movable between an open position and a closed position; a cap member (46) which mounts adjacent the inlet end (14) of the valve body (12); a compensating device (60) housed within the cap member, the compensating device (60) being accessible through the inlet end (14) of the valve body (12); a spring (26) mounted between the piston (24) and the compensating device (60), the spring (26) biasing the piston (24) toward the open position, the spring (26) being compressed when the piston (24) moves toward the closed position; and wherein the compensating device (60) is configured to rotate axially relative to the cap member (46) to vary the compression of the spring (26) to achieve a desired spring pressure, wherein the cap member (46) blocks one end of a spring chamber, wherein the compensating device (60) includes a rod (64) that projects through the cap member (46) and a head (62) that threadably screws into the cap member (46), wherein the spring (26) extends through the spring chamber and has spring end portions (86, 88) received within the cap member (46) and the piston (24), and wherein the rod (64) includes a torque transmitting member (80) to allow the compensating device (60) to be rotated relative to the cap member (46) by a tool inserted through the inlet end (14) of the valve body (12) without requiring disassembly of the valve assembly (10) to adjust a compression of the spring (26).

2. The valve assembly (10) of claim 1, wherein the cap member (46) has a threaded connection with the valve body (12) or is connected to the valve body (12) by a snap ring.

3. The valve assembly (10) of claim 1, wherein the compensating device (60) includes a pressure rate indicator (76) visible through the inlet end (14) of the valve body (12) for setting the desired spring pressure rate.

4. The valve assembly (10) of claim 1, wherein the valve body (12) includes a first housing piece (12a) and a second housing piece (12b); or wherein the valve body (12) is cast from a single piece of metal.

5. A valve assembly (10) for controlling the flow of liquid from a pressurized supply into a reservoir, the valve assembly (10) comprising: a valve body (12) having an inlet end (14) and an opposing outlet end (16); a piston (24) operative to close the valve assembly (10) in response to an increase in fluid back pressure when a predetermined liquid level is reached in the reservoir; and a spring (26) mounted between the piston (24) and a spring adjusting member, a portion of the spring adjusting member being accessible through the inlet end (14) of the valve body (12) so as to be engageable by a tool to facilitate axial movement of the spring adjusting member to vary the compression of the spring (26) to achieve a spring pressure regime, a spring chamber in which the spring (26) is positioned,a cap member (46) locking one end of the spring chamber, wherein the compensating device (60) includes a rod (64) which projects through the cap member (46) and a head (62) which threadably screws into the cap member (46), wherein the spring (26) extends through the spring chamber and has spring end portions (86, 88) received within the cap member (46) and the piston (24), and wherein the rod (64) includes a torque transmitting member (80) to enable the compensating device (60) to be rotated relative to the cap member (46) by a tool inserted through the input end (14), of the valve body (12) without requiring disassembly of the valve assembly (10) to adjust a compression of the spring (26).

6. The valve assembly (10) of claim 5, wherein the spring adjusting member has a torque transmitting member end (80) accessible through the inlet end (14) of the valve body (12) to change its axial position; wherein a tool is inserted into the torque transmitting member end (80) of the spring adjusting member to rotate the spring adjusting member to increase or decrease the gap between the piston (24) and the spring adjusting member into which the spring (26) is compressed; and wherein the spring adjusting member includes a pressure rate indicator (76) visible through the inlet end (14) of the valve body (12) to adjust the spring pressure rate.

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