Pressure retaining valve

Patent metadata

Field	Value
Publication number	US-10519988-B2
Application number	US-201414912947-A
Country	US
Kind code	B2
Filing date	Aug 14, 2014
Priority date	Sep 4, 2013
Publication date	Dec 31, 2019
Grant date	Dec 31, 2019

Abstract

A pressure retaining valve ( 1 ) has a main control piston ( 39 ) guided longitudinally displaceably in a single-piece or multiple-piece valve housing ( 29 ) and a non-return piston ( 43 ). In a pressure retaining position, a fluid-conducting connection between connection points ( 37 a, 37 b, 21 ) is shut off by the two pistons ( 39, 43 ). Connection point ( 37 a ) serves to feed media. Connection point ( 37 b ) discharges media. Connection point ( 21 ) leads to a hydraulic consumer. In a load-raising position, the two pistons ( 43 ) move relative to one another into a release position, in which the connection between the medium feed ( 37 a ) and the consumer is established. In a load-reducing position, the two pistons ( 39, 43 ) assume a spacing from one another such that the connection between the medium discharge ( 37 b ) and the consumer is established. A monitoring device ( 75 ) determines the individual switching positions of the pistons ( 39, 43 ) to ensure reliable functioning of the pressure retaining valve ( 1 ).

First claim

The invention claimed is:

1. A pressure retaining valve, comprising:
a valve housing having a main control piston and a non-return piston, each of said main control piston and said non-return piston being releasably engaged in direct contact with one another and being individually and longitudinally displaceable in said valve housing between
a pressure holding switching position closing a fluid-conducting connection between supply, tank and actuator connection ports in said valve housing by said pistons where said supply connection port supplies fluid media, said tank connection port returns fluid media and extends through said valve housing, and said actuator connection port leads to a hydraulic actuator connected to said valve housing,
a load-lifting switching position in which said pistons move relative to one another in said valve housing into a release position connecting said supply connection port in said valve housing with said actuator connection port in fluid communication and closing said tank connection port, and
a load-lowering switching position spacing said pistons from one another by a predefinable distance connecting said tank connection port in said valve housing with said actuator connection port in fluid communication and closing said supply connection port; and

a monitoring device coupled to said valve housing determining the switching positions individually of said pistons ensuring reliable functioning of the pressure retaining valve.

2. A pressure retaining valve according to claim 1 wherein
at least one of said main control piston or said non-return piston interact with a signaling device that inductively alters a field generated by a measuring device as soon as a position of said signaling device changes relative to said measuring device due to movement of at least one of said main piston or said non-return piston.

3. A pressure retaining valve according to claim 2 wherein
said signaling device comprises a control unit connected to said main control piston, said control unit having at least partially magnetic field altering constituents; and
said measuring device has an energizable winding coil generating a magnetic field.

4. A pressure retaining valve according to claim 3 wherein
said magnetic field altering constituents comprise iron compounds.

5. A pressure retaining valve according to claim 3 wherein
said control unit is part of a signal rod having a first free end engaging said main control piston and having a second free end area extending through a dual coil arrangement, said dual coil arrangement having individual coils arranged in series at a predetermined spacing along a travel direction of said signal rod.

6. A pressure retaining valve according to claim 3 wherein
said main control piston is acted on by a throttled fluid pressure, a main spring and a control pressure controlled by said actuator connection port when in the load-lowering switching position.

7. A pressure retaining valve according to claim 6 wherein
said main spring has an adjustable spring force.

8. A pressure retaining valve according to claim 2 wherein
said measuring device has a starting position calibrated relative to said valve housing, movement of said main control piston in either direction from the starting position allowing an inference to be made about the respective switching position starting from an output voltage providing a switching point detection.

9. A pressure retaining valve according to claim 8 wherein
the switching point detection determines unambiguously the respective switching position via a hysteresis loop.

10. A pressure retaining valve according to claim 8 wherein
said valve housing comprises a stop shoulder abutted by said non-return piston in the pressure holding switching position defining the starting position; and
said main control piston is movable in either direction from a position close to said stop shoulder to the load-lifting and load lowering switching positions towards said actuator connection port on a front end of said valve housing.

11. A pressure retaining valve according to claim 2 wherein
said measuring device is connected to evaluation electronics.

12. A pressure retaining valve according to claim 11 wherein
said evaluation electronics comprises an LED display visually indicating the switching positions.

13. A pressure retaining valve according to claim 1 wherein
a control valve is connected to said valve housing and controls a fluid media supply and a fluid media return and operates both of said main control piston and said non-return piston.

14. A pressure retaining valve according to claim 13 wherein
said control valve comprises a 4/3 proportional directional valve.

15. A pressure retaining valve according to claim 1 wherein
in the load-lowering switching position of said main control piston, a throttled fluid pressure, a main spring and a control pressure act on the hydraulic actuator via said actuator connection port.

16. A pressure retaining valve according to claim 1 wherein
said main control piston and said non-return piston are coaxial relative to one another relative to a longitudinal axis and are movable along said longitudinal axis.

17. A pressure retaining valve according to claim 16 wherein
said non-return piston is located between said main control piston and said actuator connection port along said longitudinal axis.

18. A pressure retaining valve according to claim 16 wherein
said supply and tank connection ports are located radially next to said pistons relative to said longitudinal axis and are spaced from each other relative to said longitudinal axis.

19. A pressure retaining valve according to claim 1 wherein
said non-return piston is coaxial to and is located between said main control piston and said actuator connection port along a longitudinal axis, said main control piston and said non-return piston being movable along said longitudinal axis.

20. A pressure retaining valve according to claim 1 wherein
said main control piston and said non-return piston are movable to positions closing all of said connection ports simultaneously.

21. A pressure retaining valve according to claim 1 wherein
said supply and tank connection ports comprises first and second openings, respectively, in said valve housing separable from and another by a part of said valve housing; and
said actuator connection port comprises a third opening in said valve housing separable from said first and second openings by a part of said valve housing.

22. A pressure retaining valve according to claim 21 wherein
said third opening is an axial end of said valve housing; and
said first and second openings are in lateral sides of said valve housing.

23. A pressure retaining valve according to claim 1 wherein
each of said main control piston and said non-return piston is an integral structure without relatively movable parts.

24. A pressure retaining valve according to claim 1 wherein
said supply connection port and said tank connection port are directly engaged by said main control piston and said non-return piston.

25. A pressure retaining valve according to claim 1 wherein
hydraulic fluid is conveyed through said ports.

26. A pressure retaining valve according to claim 1 wherein
said non-return piston is hollow.

27. A pressure retaining valve, compris

Assignees

• Hydac Fluidtechnik Gmbh

Inventors

• Schneider Gerd
• Bill Markus

Classifications

• F15B13/0401 Primary

  Valve members; Fluid interconnections therefor · CPC title

• F16K37/0041

  for measuring valve parameters (F16K37/0033 takes precedence) · CPC title

• F15B2013/0409

  Position sensing or feedback of the valve member · CPC title

• F15B13/01 Primary

  Locking-valves or other detent {i.e. load-holding} devices · CPC title