Valve assembly with adjustable spring seat

A valve assembly includes a valve body, a first spring seat disposed within the valve body, a preload spring disposed within the valve body and mated with the first spring seat, and a second spring seat disposed within the valve body and mated with the preload spring. The second spring seat is adjustably mated to the valve body.

BACKGROUND

Valves, regulators, and other flow-control mechanisms typically include a spring that is used to apply a bias force to a valve or regulator member. For example, the spring biases the valve or regulator member to a default open or closed position. When fluid pressure in the valve or regulator exceeds the bias force of the spring, the valve or regulator member moves and compresses the spring. The movement of the valve or regulator member changes the flow through the valve or regulator.

SUMMARY

A valve assembly according to an example of the present disclosure includes a valve body, a first spring seat disposed within the valve body, a preload spring disposed within the valve body and mated with the first spring seat, and a second spring seat disposed within the valve body and mated with the preload spring. The second spring seat is adjustably mated to the valve body.

A further embodiment of any of the foregoing embodiments include an end cap that is mated to the second spring seat and that is fixedly detachable with the valve body.

In a further embodiment of any of the foregoing embodiments, the end cap is fixedly detachable with the valve body via at least one fastener.

In a further embodiment of any of the foregoing embodiments, the end cap includes at least one elongated slot through which the at least one fastener is fixedly attachable to the valve body.

In a further embodiment of any of the foregoing embodiments, the second spring seat is adjustably mounted in the valve body on threads.

In a further embodiment of any of the foregoing embodiments, the end cap is rotatable and the second spring seat is engaged with the end cap in a keyed joint such that rotation of the end cap rotates the second spring seat on the threads to change a position of the second spring seat.

In a further embodiment of any of the foregoing embodiments, the keyed joint includes at least one arm and at least one opening, and the at least one arm extends through the at least one opening such that the end cap and the second spring seat are rotationally locked together.

In a further embodiment of any of the foregoing embodiments, the at least one arm is radially offset from a central axis of rotation of the end cap.

In a further embodiment of any of the foregoing embodiments, the at least one arm has a tip end that defines a bound of a range of movement of the first spring seat beyond which the first spring seat cannot compress the preload spring against the second spring seat.

A further embodiment of any of the foregoing embodiments include a valve member that is moveable against the preload spring through the first spring seat.

A valve assembly according to an example of the present disclosure includes a valve body that defines at least one valve passage and a preload spring within the valve body. The preload spring includes a first end and a second end, a first spring seat within the valve body at the first end of the preload spring, a valve member disposed in the at least one valve passage and moveable against the preload spring through the first spring seat, and a second spring seat within the valve body at the second end of the preload spring. The second spring seat is mounted in the valve body on threads, and a rotatable end cap is fixedly detachable with the valve body. The rotatable end cap is engaged in a keyed joint with the second spring seat such that rotation of the end cap rotates the second spring seat on the threads to change a set position of the second spring seat.

In a further embodiment of any of the foregoing embodiments, the keyed joint includes at least one arm and at least one opening, and the at least one arm extends through the at least one opening such that the rotatable end cap and the second spring seat are rotationally locked together.

In a further embodiment of any of the foregoing embodiments, the at least one arm is radially offset from a central axis of rotation of the rotatable end cap.

In a further embodiment of any of the foregoing embodiments, the at least one arm has a tip end that defines a bound of a range of movement of the first spring seat beyond which the first spring seat cannot compress the preload spring against the second spring seat.

In a further embodiment of any of the foregoing embodiments, rotation of the rotatable end cap does not change an axial position of the tip end along the axis of rotation of the rotatable end cap.

DETAILED DESCRIPTION

FIG. 1Aschematically illustrates an example valve assembly20. As will be described, the valve assembly20is adjustable with respect to the amount of spring force provided by an internal preload spring.

The valve assembly20includes a valve body22that houses a preload spring24. For example, although not limited, the preload spring24can be a helical coil spring that generally extends about a central axis A. The preload spring24includes a first end24aand a second end24b. A first spring seat26is situated within the valve body22at the first end24aof the preload spring24. A second spring seat28is situated within the valve body22at the second end24bof the preload spring24. The preload spring24is mated, or attached, with the first spring seat26and the second spring seat28.

During operation of the valve assembly20the second spring seat28is stationary and the first spring seat26is movable against the spring force of the preload spring24. For example, the valve assembly20includes a valve member30that is situated in one or more valve passages32in the valve body22. The position of the valve member30controls fluid flow through the valve assembly20. In the illustrated example, the valve member30is a three-way valve; however, it is to be appreciated that the examples herein are also applicable to other types of valves or regulators.

The valve member30is movable through the first spring seat26against the spring force of the preload spring24. For example, the valve member30is pressure-actuated. When the fluid pressure behind the valve member30exceeds the spring force of the preload spring24the valve member30compresses the preload spring24, as shown inFIG. 1B. When the fluid pressure is less than the spring force, the preload spring24biases the valve member30to a default position, which is shown inFIG. 1A.

The magnitude of the spring force depends upon the amount of initial compression of the preload spring24. The amount of initial compression in turn depends on the position of the second spring seat28in the valve assembly20. The position of the second spring seat28can be adjusted to change the spring force and thus adjust the pressure at which the valve member30actuates. In this regard, the second spring seat28is adjustably mated to the valve body22. In the illustrated example, the second spring seat28is mounted in the valve body22on threads34. Rotation of the second spring seat28in a clockwise or counterclockwise direction thus changes the axial position of the second spring seat28along the central axis A. This varies the spring preload.

The valve assembly20further includes an end cap36that enables a user to adjust the position of the second spring seat28. The end cap36is fixably detachable with the valve body22. For example, the end cap36can be fixed, or secured, with the valve body22using one or more fasteners38. The end cap36is detachable from the valve body22by removing the one or more fasteners38.

The second spring seat28is engaged with the end cap36in a keyed joint40. The keyed joint40rotationally locks the end cap36and the second spring seat28together. Rotation of the end cap36about central axis A (when the fasteners38are removed) thus rotates the second spring seat28via the keyed joint40.

Referring also toFIGS. 2 and 3, which show exploded views of selected portions of the valve assembly20, the keyed joint40includes at least one arm42(two shown) and at least one opening44(two shown). In this example, the arms42are on the end cap36and the openings44are in the second spring seat28. As will be appreciated, the end cap36could alternatively be configured with the openings44and the second spring seat28could be configured with the arms42.

The arms42extend through the openings44and thus rotationally lock the second spring seat28and end cap36together. In this regard, the cross-sectional geometry of the arms42corresponds to the cross-sectional geometry of the openings44so that the arms42fit into the openings44. Upon clockwise or counterclockwise rotation of the end cap36when the fasteners38are removed, the arms42rotate the second spring seat28. The rotation moves the second spring seat28axially via the threads34to change the set position of the second spring seat28.

In the illustrated example, the arms42are generally radially offset from the central axis A. The offset ensures that the arms42generate a moment force on the second spring seat28, to rotate the second spring seat28when the end cap36is rotated. Additionally, although it is conceivable that a single, exclusive arm42could be used, multiple arms42that are uniformly circumferentially spaced as shown may provide a more uniform application of rotational force on the second spring seat28. The uniform application of rotational force may reduce the potential that the second spring seat28jams on the threads34.

The end cap36can be rotated incrementally between rotational positions in which holes36ain the end cap36align with corresponding holes22ain the valve body22. The size of the rotational increments depends upon the number of pairs of holes22a/36aprovided. For example, eight pairs of circumferentially-spaced holes22a/36aprovides rotational increments of 45°, six pairs of circumferentially-spaced holes22a/36aprovides increments of 60°, and four pairs of circumferentially-spaced holes22a/36aprovides increments of 90°.

Additionally, the rotational increments and pitch of the threads34can be configured to provide a predetermined incremental magnitude of axial movement of the second spring seat28for a given increment of rotation of the end cap36. Coupled with Hooke's Law and knowledge of the spring constant of the preload spring24, the spring force can readily be calculated for given incremental magnitudes of axial movement of the second spring seat28.

Once the position of the second spring seat28is set, the fasteners38are inserted through holes36ain the end cap36and secured to the valve body22. The securing of the end cap36to the valve body22prevents rotation of the end cap36and thus also prevents rotation of the second spring seat28. The fasteners38therefore also serve to indirectly lock second spring seat28in a stationary set position. The adjustment of the second spring seat28therefore does not require complete removal of the end cap36or opening of the valve assembly to directly access the second spring seat28. Once the adjustment is locked, the pre-load is repeatable and reliable in that it will not change during operational use.

In this manner, the set position of the second spring seat28can be adjusted in order to adjust the magnitude of the spring force of the preload spring24. For example, inFIG. 1A, the stationary set position of the second spring seat28is toward the left side of the valve body22. In this state of compression the preload spring24provides a relatively low spring force on the first spring seat26and valve member30. As shown inFIG. 4A, the stationary set position of the second spring seat28is farther to the right. In this state of greater compression the preload spring24provides a relatively higher spring force on the first spring seat26and valve member30. As can be appreciated, the second spring seat28can also be adjusted to other stationary set positions to provide additional spring forces. When the fluid pressure behind the valve member30exceeds the spring force of the preload spring24the valve member30compresses the preload spring24, as shown inFIG. 4B. When the fluid pressure is less than the spring force, the preload spring24biases the valve member30to a default position, which is shown inFIG. 4A.

In the actuated state as shown inFIGS. 1band4B, the valve member30actuates against the first spring seat26to compress the preload spring24. In this regard, the arm or arms42also serve as a stop. For example, each of the arms42includes a tip end42athat defines a bound of a range of movement of the first spring seat26beyond which the first spring seat26cannot compress the preload spring24against the second spring seat28. Although the end cap36is rotatable, the end cap36itself does not move axially. Thus, the position of the stop provided by the tip ends42aof the arms42is constant and ensures that the available stroke of the valve member30is constant for a given spring set position even though the spring force may change.

FIG. 5illustrates a modified example of an end cap136. In this example, the end cap136includes elongated slots136athrough which the fasteners38can be inserted to secure the end cap136to the valve body22. The elongated slots136aare arced and provide an ability to “fine-tune” the stationary set position of the second spring seat28. For example, the end cap136can be rotated clockwise or counterclockwise between rotational positions in which the elongated slots136aalign with the holes22a. Upon adjustment to an aligned position, the end cap136can further be rotated by small amounts corresponding to the arc length of the elongated slots136ato fine-tune the set position of the second spring seat28.