A pilot valve (2) for controlling operation of a hydraulically-actuated pressure reducing valve, the pilot valve including a housing (4), and a first valve member (15) mounted in the housing for longitudinal movement along an axis relative to the housing and to a second valve member (22) in response
A pilot valve (2) for controlling operation of a hydraulically-actuated pressure reducing valve, the pilot valve including a housing (4), and a first valve member (15) mounted in the housing for longitudinal movement along an axis relative to the housing and to a second valve member (22) in response to the outlet pressure of the pressure reducing valve. The first valve member is provided with an aperture (20) and the second valve member comprises a closure portion which varies the effective flow cross section of the aperture in accordance with relative longitudinal movement between the first and second valve members. An adjuster (26) controls the relative rotational position of the first and second valve members, the closure portion having a profile such that relative rotation between the first and second valve members causes the closure portion to vary the effective flow cross section of the aperture (20).
대표청구항▼
1. A fluid supply system comprising (i) a fluid-actuated pressure reducing valve and (ii) a pilot valve connected to the fluid-actuated pressure reducing valve for controlling an output pressure of the fluid-actuated pressure reducing valve, the pilot valve including: a housing, a first valve member
1. A fluid supply system comprising (i) a fluid-actuated pressure reducing valve and (ii) a pilot valve connected to the fluid-actuated pressure reducing valve for controlling an output pressure of the fluid-actuated pressure reducing valve, the pilot valve including: a housing, a first valve member and a second valve member whose relative positions control flow through the pilot valve; the first valve member being provided on a movable spring-engaging member which engages a spring and which is mounted in the housing for movement relative to the housing in a longitudinal direction in response to the outlet pressure of the pressure reducing valve, movement of the spring-engaging member changing the relative positions of the first and second valve members;an adjuster for varying the relative rotational positions of the first and second valve members about the longitudinal direction for a given position of the spring-engaging member, so as to cause the output pressure of the pressure reducing valve to alter; and a motor connected to the adjuster for rotating the adjuster; wherein one of the first and second valve members includes an aperture directed laterally of the longitudinal direction; the other of the first and second valve members includes a portion defining an edge which is positively-inclined relative to the longitudinal direction, and which extends completely across the aperture, and which is arranged for relative sliding movement across the aperture to vary the flow cross section through the aperture and thus the flow through the pilot valve; and the adjuster is arranged to adjust the relative rotational positions of the edge-defining portion and the aperture by sliding movement so as to adjust the flow cross section through the aperture for a given position of the spring-engaging member. 2. The fluid supply system of claim 1, wherein the edge has a constant inclined angle across the aperture. 3. The fluid supply system of claim 1, wherein the adjuster causes rotation of the second valve member. 4. The fluid supply system of claim 3, wherein the second valve member is fixed, relative to the housing, with respect to the longitudinal direction. 5. The fluid supply system of claim 4, wherein the second valve member is fixed, relative to the housing, except to the extent that there is movement of the edge-defining portion effected by the adjuster. 6. The fluid supply system of claim 1, wherein the aperture is provided in the first valve member and the edge-defining portion is provided by the second valve member. 7. The fluid supply system of claim 6, wherein the first valve member comprises an axially extending tubular member which is in fluid communication with a control chamber of the pressure reducing valve, the tubular member having the aperture therethrough and the outlet from the aperture being in communication with the outlet pressure of fluid from the pressure reducing valve. 8. The fluid supply system of claim 7, wherein the second valve member is in the form of a sleeve arranged coaxially with the first valve member. 9. The fluid supply system of claim 8, wherein the sleeve is mounted on the outside of the first valve member. 10. The fluid supply system of claim 8, wherein the sleeve has a circumferentially extending hole therein which defines the edge of the edge-defining portion. 11. The fluid supply system of claim 1, wherein there is a plurality of apertures and a corresponding plurality of edge-defining portions arranged for relative sliding movement across the apertures to vary the flow cross section through the apertures. 12. The fluid supply system of claim 11, wherein there are two diametrically opposite apertures. 13. The fluid supply system of claim 1, wherein the adjuster is connected to a position indicator arranged to indicate the position of the second valve member relative to the housing. 14. The fluid supply system of claim 1, wherein the edge-defining portion varies the effective flow cross section of the aperture in accordance with relative longitudinal movement between the first and second valve members; and the adjuster is arranged to adjust the relative rotational positions of the first and second valve members, the edge-defining portion having a profile such that relative rotation between the first and second valve members causes the edge-defining portion to vary the effective flow cross section of the aperture. 15. The fluid supply system of claim 11, wherein the plurality of edge-defining portions are provided on a single member. 16. The fluid supply system of claim 1, wherein the aperture is circular. 17. The fluid supply system of claim 1, wherein the edge of the edge-defining portion is defined by an axially-directed end of said other valve member. 18. The fluid supply system of claim 1, wherein the adjuster is arranged to adjust the relative rotational positions of the edge-defining portion and the aperture by sliding movement, so as to adjust the flow cross section through the aperture for a given position of the spring-engaging member, without longitudinal displacement relative to the housing. 19. The fluid supply system of claim 1, further comprising a controller configured to control the pilot valve in dependence on the output flow rate of the fluid-actuated pressure reducing valve. 20. The fluid supply system of claim 1, wherein the motor is housed in a motor housing, which is fixed to the housing of the pilot valve. 21. A method of using a fluid supply system comprising the steps of: providing a fluid supply system including a fluid-actuated pressure reducing valve and a pilot valve connected to the fluid-actuated pressure reducing valve for controlling an output pressure of the fluid-actuated pressure reducing valve, where the pilot valve includes a housing, a first valve member and a second valve member whose relative positions control flow through the pilot valve, the first valve member being provided on a movable spring-engaging member which engages a spring and which is mounted in the housing for movement relative to the housing in a longitudinal direction in response to the outlet pressure of the pressure reducing valve, movement of the spring-engaging member changing the relative positions of the first and second valve members, an adjuster for varying the relative rotational positions of the first and second valve members about the longitudinal direction for a given position of the spring-engaging member, so as to cause the output pressure of the pressure reducing valve to alter, and a motor connected to the adjuster for rotating the adjuster, wherein one of the first and second valve members includes an aperture directed laterally of the longitudinal direction; the other of the first and second valve members includes a portion defining an edge which is positively-inclined relative to the longitudinal direction, and which extends completely across the aperture, and which is arranged for relative sliding movement across the aperture to vary the flow cross section through the aperture and thus the flow through the pilot valve, and the adjuster is arranged to adjust the relative rotational positions of the edge-defining portion and the aperture by sliding movement so as to adjust the flow cross section through the aperture for a given position of the spring-engaging member; andoperating the fluid supply system to control the output pressure of the fluid-actuated pressure reducing valve. 22. The method of claim 21, further comprising the step of: using a controller to control the pilot valve in dependence on an output flow rate from the fluid-actuated pressure reducing valve. 23. The method of claim 22, wherein the fluid supply system is a water supply system. 24. The fluid supply system of claim 1, wherein the aperture has a maximum dimension and wherein the edge that is positively-inclined relative to the longitudinal direction is longer than said maximum dimension. 25. The fluid supply system of claim 1, wherein the edge that is positively-inclined relative to the longitudinal direction is extendable completely across the aperture such that the aperture is entirely occluded by the portion defining the edge on one side of the edge and is entirely open on the other side of the edge. 26. The fluid supply system of claim 1, wherein the edge that is positively-inclined relative to the longitudinal direction forms an edge of a second aperture that has a different geometry from, and is larger than, the aperture.
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이 특허에 인용된 특허 (8)
Matsumoto Kuniaki (Kokubunji JPX), Control of the flow rate and fluid pressure in a pipeline network for optimum distribution of the fluid to consumers.
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