Safety valve with pressure indicator

[0001] The present invention generally relates to fluid control valves for use in pneumatic circuits and, more particularly, relates to safety shut-off valves for use in pneumatic circuits which provides a pressure indicator on the output to improve safety thereof.

[0002] The manufacturing community utilizes air cylinders and other air actuated devices to control machinery, operate tools, and to perform various other manufacturing activities. These devices may be air actuated in a single direction with the return being accomplished by springs and/or gravity, or these devices may be air actuated in both directions with the control of the device being accomplished with an air valve. At certain times, the need arises to disconnect the supply of compressed air to the device. For example, one such time occurs when service or maintenance is required on the system incorporating air actuated devices. When disconnection of the supply of compressed air is required, normal precautions dictate that the disconnect valve must be locked to prevent reactivation of any valves, tools or associated machinery in the system while the system is being maintained and/or repaired. In the case of a system incorporating air operated equipment, a lockout valve should be used to cut off the compressed air supply to the system and to exhaust any stored or residual downstream air.

[0003] However, during the exhaust process, it is often important for the operator to verify that air pressure has in fact been exhausted from the output end of the lock out valve. Unfortunately, in conventional lockout valves, the pressure at the output is not readily measurable by the user, and hence the operator is unable to confirm that the exhaust process was completed to a safe pressure level. Therefore, in the interest of caution, it is preferable to confirm that pressure has been reduced to a safe level prior to service and/or repair.

[0004] Accordingly, there exists a need in the relevant art to provide a means to determine the outlet pressure of a fluid control valve to determine when a predetermined pressure is achieved. Additionally, there exists a need in the relevant art to incorporate a pressure indicator in a fluid control valve to improve the safety features thereof by providing a simple method of determining when air pressure has been reduced at the output or conversely reestablished.

[0005] The present invention provides the art with a fluid control valve having an adjustable soft start capability and pressure indicator device. The fluid control valve isolates an input port and connects an outlet port to an exhaust port when the fluid control valve is in its closed position. A system is provided for locking the fluid control valve in the closed position. The indicator device is used to provide an indication of the pressure within the outlet port to ensure safe operation.

[0006] Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

[0014] The following description of the preferred embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.

[0015] Referring now to the drawings in which like reference numerals designate like or corresponding parts throughout the several views, there is shown in FIG. 1 a fluid control valve incorporating a soft startup capability and pressure indicator system in accordance with the present invention, which is designated generally as reference numeral 10. Fluid control valve 10 comprises a valve housing 12 and a valve spool assembly 14.

[0016] Referring now to FIGS. 1 and 2, valve housing 12 defines a locking flange 18 and a longitudinally extending bore 20 which communicates with an inlet port 22 through an inlet chamber 24, an outlet port 26 through an outlet chamber 28 and an exhaust port 30 through an exhaust chamber 32. Inlet port 22 is adapted to be connected to a source of compressed air, outlet port 26 is adapted to be connected to a load line of an air operated device and exhaust port 30 is adapted to be connected to a muffler or similar device leading to the outside atmosphere. Bore 20 defines a first sealing surface 34 located between chambers 32 and 28, a second sealing surface 36 located between chambers 28 and 24 and a third sealing surface 38 located between chamber 24 and atmosphere. An annular groove 40 extends into housing 12 from bore 20 to provide a seat for a retaining spring 42 which cooperates with valve spool assembly 14 to releasably hold fluid control valve 10 into either a closed or an open position. Locking flange 18 defines an aperture 44 which accepts a padlock 46 or the like which cooperates with valve spool assembly 14 in order to lock fluid control valve 10 in its closed position. Sealing surfaces 34, 36 and 38 cooperate with valve spool assembly 14 to isolate fluid pressure within inlet port 22 and connect outlet port 26 with exhaust port 30 when fluid control valve 10 is in a closed position and to isolate exhaust port 30 and connect inlet port 22 with outlet port 26 when fluid control valve 10 is in an open position.

[0017] Still referring to FIGS. 1 and 2, valve housing 12 further includes an indicator port 51 which communicates with outlet chamber 28. A pressure indicator device 53 is coupled to an exterior end of indicator port 51 to operably measure air pressure in outlet chamber 28 and provide exterior indication of such air pressure to a user. Indicator port 51 may be in fluid communication with any area on fluid control valve 10, including a communicating port to a main stem or in handle 52. Preferably, indicator device 53 is a pop-up type indicator, which operates to extend at a first predetermined pressure and retract at a second predetermined pressure. Such a pop-up type indicator can be obtained from CLIPPARD. However, it should be appreciated that other indicator devices may also be used with the present invention. By way of non-limiting example, indicator device 53 may be an electrical pressure switch, which produces a unique electrical signal in response to either when a predetermined pressure is achieved, a predetermined pressure change is achieved, or other various pressure related settings are achieved; a light or sound indicator, which produces an illumination or aural signal in response to either a predetermined pressure or varying pressure settings; or a gauge having a pressure readout face. More particularly, indicator device 53 may be a popup type, extending pin type, rollover, or other type of visual interfacing device, including an electrical switch and light (which may be very low power battery (self contained power source) or 110 volt).

[0018] Referring to FIGS. 1 and 3, valve spool assembly 14 comprises a spool body 50, a handle 52, an exhaust spool segment 54, a piston 56 and an adjustment stem 58. Spool body 50 is a generally cylindrical member defining a stem portion 60 located at one end which meets a plug portion 62 to form a radial shoulder 64. Spool body 50 defines an axially extending bore 66 which extends through stem portion 60 and plug portion 62. Bore 66 includes a first threaded portion 68 located at the end of stem portion 60, a stepped portion 70 located in the middle of bore 66 near shoulder 64 and a second threaded portion 72 located at the end of plug portion 62. A pair of angular passages 74 extend from shoulder 64 into bore 66 as is shown in FIG. 3.

[0019] The exterior surface of plug portion 62 defines a first annular seal groove 76 within which is disposed a seal ring 78, a second annular seal groove 80 within which is disposed a seal ring 82 and a pair of annular grooves 84 which mate with spring 42 to releasably hold fluid control valve 10 into either its closed or open position. Handle 52 is secured to the end of plug portion 62 opposite to stem portion 60 and is retained by a roll pin 86 which is pressed through a hole 88 extending through handle 52 and a slot 90 formed in plug portion 62 of spool body 50. Handle 52 is attached to spool body 50 after spool body 50 is inserted into bore 20 of housing 12. A through bore 92 extends through handle 52 to provide access to adjustment stem 58.

[0020] Exhaust spool segment 54 is secured to the end of stem portion 60 opposite to plug portion 62 by a bolt 94 which is threadingly received within threaded portion 68 of bore 66. A hole 96 extends through spool segment 54 to mate with a hole 98 which extends through stem portion 60 to intersect with bore 66. The exterior surface of spool segment 54 defines an annular groove 100 within which is disposed a seal ring 102.

[0021] Piston 56 is slidingly received on stem portion 60 of spool body 50 between shoulder 64 and exhaust spool segment 54. A spring 104 is disposed between piston 56 and exhaust spool segment 54 to bias piston 56 towards shoulder 64. The external surface of piston 56 defines an annular groove 106 within which is disposed a seal ring 108.

[0022] Adjustment stem 58 extends through bore 92 in handle 52, through bore 66 in spool body 50 and includes a portion 110 which is threadingly received by threaded portion 72 of bore 66. The end of stem 58 located within bore 66 has a tapered head 112 which cooperates with stepped portion 70 of bore 66 to provide a variable orifice for the adjustable by-pass of fluid control valve 10. A seal 114 is disposed on stem 58 to prevent by-pass flow from leaking to atmosphere via clearances along the length of stem 58. The end of stem 58 opposite to tapered head 112 which is located within bore 92 defines a slot 116 which is utilized to rotate stem 58 to adjust the size of the orifice, the by-pass orifice or the by-pass flow area. Rotation of stem 58 thus adjusts the position of tapered head 112 with respect to stepped portion 70 of bore 66 which in turn adjusts the pressure build up rate at which the soft startup feature of the present invention operates.

[0023] The closed position of fluid control valve 10 is shown in FIG. 1. Valve spool assembly 14 is fully inserted into valve housing 12 with its travel being limited by handle 52 contacting a radial end 120 of housing 12. Inlet port 22 is isolated due to seal 82 contacting sealing surface 36 and seal 78 contacting sealing surface 38. Outlet port 26 is open to exhaust port 30 since seal ring 102 on exhaust spool segment 54 is in a non-sealing position, thus, allowing free flow from outlet port 26 to atmosphere at port 30. Piston 56 is disposed adjacent to shoulder 64 allowing the free flow of pressurized air from output port 26 to exhaust port 30. As pressurized air flows from output port 26 to exhaust port 30, the pressure within outlet chamber 28 decreases. Once this pressure is below a predetermined minimum pressure, indicator device 53 produces an indication (in this case, a retraction of a colored plunger within the body of the indicator) to inform the user that the pressure within outlet chamber 28 and outlet port 26 are sufficiently low. This prevents any inadvertant actuation of the air operated device (not shown) and/or prevents disconnection of pressurized pipes or tubes, which may pose a danger.

[0024] Fluid control valve 10 can be locked in this closed position by inserting padlock 46 into aperture 44 of locking flange 18 as shown in FIG. 1. The padlock extends into an annular groove 122 located in handle 52. Once padlock 46 has been assembled with fluid control valve 10, the opening of fluid control valve 10 is prohibited due to valve spool assembly 14 being unable to move relative to housing 12.

[0025] Referring now to FIGS. 3 and 4, the opening of fluid control valve 10 begins with the removal of padlock 46. With the removal of padlock 46, handle 52 can be pulled to move valve spool assembly 14 to its activated position as shown in FIG. 4. In this activated position, seal 82 is moved from one side of inlet chamber 24 where it contacts sealing surface 36 to the opposite side of inlet chamber 24 to contact sealing surface 38. This movement moves plug portion 62 of spool body 50 past inlet chamber 24 but piston 56 remains in position with seal 108 contacting sealing surface 36 to isolate both inlet port 22 and outlet port 26 from exhaust port 30. The soft startup feature of the present invention is achieved in part by passages 74. Inlet pressurized air from inlet port 22 is provided to inlet chamber 24. Pressurized fluid passes through passages 74 and into bore 66 through the opening defined by tapered portion 112 of stem 58 and stepped portion 70 of bore 66. Pressurized air flows down bore 66 and exits bore 66 through holes 96 and 98 to begin the slow pressurization of the fluid lines connected to outlet port 26. The rate of flow of pressurized air form inlet port 22 to outlet port 26 is controlled by the opening between tapered portion 112 and stepped portion 70 which is adjustable by the rotation of threaded stem 68 using a screwdriver and slot 116. The size of the opening controls the rate of pressurization of the load connected to outlet port 26. As pressurized air flows into output port 26, the pressure within outlet chamber 28 increases. Once this pressure is above the first predetermined pressure, indicator device 53 produces an indication (in this case, an extension of a colored plunger within the body of the indicator) to inform the user that the pressure within outlet chamber 28 and outlet port 26 is sufficiently high. This informs the user that sufficient pressure is available to actuate the air operated device (not shown) or that specific tubes or pipes are pressurized.

[0026] Piston 56 is initially held in its lower position away from shoulder 64 due to the pressurized air which is provided to inlet chamber 24. The air pressure acts against the top surface of piston 56 to keep piston 56 in its lower position. This position of piston 56 is maintained by the pressure within inlet chamber 24 until the pressure builds up in outlet chamber 28 due to the by-pass system described above. When the pressure within outlet chamber 28 in combination with the load of spring 104 exceed the load exerted by the pressure within inlet chamber 24 piston 56 is moved from the position shown in FIG. 4 to the position shown in FIG. 5 which is the fully open position of fluid control valve 10.

[0027] In the fully open position as shown in FIG. 5, piston 56 has moved to its position immediately adjacent to shoulder 64. Inlet port 22 is fully open to outlet port 26. Seals 78 and 82 are in contact with sealing surface 38 and seal 102 is in contact with sealing surface 34. As the pressure in outlet chamber 28 reaches its full operational pressure, indicator device 53 either indicates that this operational pressure has been achieved or is above some other predetermined level.

[0028] When it is desired to close fluid control valve 10, valve spool assembly 14 is moved from the position shown in FIG. 5 to the position shown in FIG. 1 to instantly cut off the supply of pressurized air from inlet port 22 and release the pressurized air from outlet port 26 to exhaust port 30.

[0029] Alternatively, as seen in FIG. 6, pressure indicator device 53′ may be coupled to an exterior end of an indicator port 51′ disposed in a valve spool assembly 14′. Valve spool assembly 14′ is similar in construction and operation to the aforementioned valve spool assembly 14. Therefore, additional description of valve spool assembly 14′ is not believed to be necessary.

[0030] The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.