Pressure-responsive shut-off valve

• US 4,402,340 A
• Filed: 05/01/1981
• Issued: 09/06/1983
• Est. Priority Date: 05/01/1981
• Status: Expired due to Fees

• Current Assignee: Hanford N. Lockwood, Jr.
• Original Assignee: Hanford N. Lockwood, Jr.
• Inventors: Lockwood, Hanford N. Jr.
• Primary Examiner(s): Nilson, Robert G.
• Application Number:
  US06/259,724
• Time in Patent Office: 858 Days
• Field of Search: 137/322, 137/493, 137/493.7, 137/516.29, 141/18, 141/21, 222/3, 251/83, 251/210, 251/149.8
• US Class Current: 137/493.7
• CPC Class Codes: F16K 1/305 with valve member and actuator on the same side of the seat
• CPC Class Codes: F16K 1/307 Additional means used in combination with the main valve
• CPC Class Codes: F17C 13/04 Arrangement or mounting of valves valves per se F16K ; snap-coupling of nipples F16L37/00
• CPC Class Codes: F17C 2205/0329 manually actuated
• CPC Class Codes: F17C 2205/0335 Check-valves or non-return valves
• CPC Class Codes: F17C 2205/0382 Constructional details of valves, regulators
• CPC Class Codes: F17C 2205/0394 in direct contact with the pressure vessel
• CPC Class Codes: F17C 2227/048 by maintaining residual pressure
• CPC Class Codes: Y10T 137/6137 Longitudinal movement of valve
• CPC Class Codes: Y10T 137/7778 Axes of ports perpendicular
• CPC Class Codes: Y10T 137/7868 Resilient gasket

Abstract

A combined manual and pressure-responsive shut-off valve, intended particularly for use with high pressure gas cylinders, is disclosed. The valve includes a single seat and a single plug, the plug having a first sealing surface for closing against a low residual pressure in the cylinder and a second sealing surface for closing against a relatively high cylinder pressure. A pressure-responsive actuator engages the first sealing surface against the seat whenever pressure in the cylinder falls below a predetermined minimum. A manual actuator engages the second sealing surface against the valve seat to close against a wide range of pressures. The seat is specifically configured to conform to the plug. Means are provided for refilling the cylinder without removing the combined valve. In one embodiment, a special tool is provided for opening the pressure-responsive actuator. In a second embodiment, a bypass check valve is provided to allow gas to flow into the cylinder.

Claims

1. A shut-off valve for use with a pressurized gas cylinder, said shut-off valve comprising:

a body having an inlet port, an outlet port, and a passageway therebetween;

a seat disposed in the passageway;

a plug having a soft surface for sealing against the seat to contain a relatively low pressure at the inlet port and a hard surface for sealing against the seat to contain a relatively high pressure at the inlet port, said soft and hard surfaces being axially spaced apart so that the soft surface engages the seat before the hard surface engages the seat;

pressure-responsive means for automatically engaging the plug against the seat with a first preselected force so that only the soft sealing surface engages the seat whenever the pressure in the cylinder falls below a predetermined level; and

,

manual means for engaging the plug against the seat with a second preselected force greater than the first preselected force so that the hard sealing surface engages the seat.

2. A shut-off valve as in claim 1, wherein the valve seat includes a first seating surface engaging the first sealing surface on the plug and a second seating surface for engaging the second sealing surface on the plug.

3. A shut-off valve as in claim 2, wherein the first and second mating surfaces on the valve seat are axially spaced apart, whereby the soft sealing surface engages the first mating surface and the hard sealing surface engages the second mating surface when the valve plug is fully disposed against the valve seat.

4. A shut-off valve as in claim 1, wherein the first sealing surface is a relatively soft elastomeric "O" ring.

5. A shut-off valve as in claim 4, wherein the "O" ring has a Rockwell hardness in the range from R49 to R103.

6. A shut-off valve as in claim 1, wherein the second sealing surface is a relatively hard insert.

7. A shut-off valve as in claim 6, wherein the insert has a Rockwell hardness in the range from R108 to R120.

8. A pressure-responsive check valve for use with a pressurized gas cylinder, said check valve comprising:

a body having a passageway through which gas flows from an inlet to an outlet;

an annular shoulder surrounding the passageway, said shoulder including a generally chamfered mating surface which depends from the shoulder;

a plug for sealing against the shoulder, said plug being reciprocally mounted within the passageway and including a relatively soft surface aligned with the chamfered surface and a relatively hard surface aligned with the shoulder;

first means for moving the plug to engage the soft surface of the plug with the chamfered mating surface of the valve seat when the pressure at the inlet has decreased to a predetermined set point so that the flow of gas through the passageway is shut off when the pressure at the inlet reaches the set point, said first means comprising a spring which at one end engages the plug and at the other end is fixed within the passageway so that said spring applies a constant closing force on the plug; and

second means which is independent of the first means for moving the plug to engage the hard surface of the plug with the shoulder so that the flow of gas through the passgeway can be shut off against pressure at the inlet which exceeds the set point;

whereby the relatively soft surface assures a seal at low gas pressure and the relatively hard surface assures a seal at high pressure.

9. A pressure-responsive check valve system for use with a pressurized gas cylinder, said check valve system comprising:

a check valve which includes;

a valve body having an inlet and an outlet and a passage therebetween;

a valve seat which defines a portion of the passageway;

a valve plug reciprocably mounted within the valve body, said plug having a shoulder and being capable of engaging the valve seat to block the flow of gas through the passageway;

means for urging the valve plug against the valve seat to shut off the flow of gas in the passageway, said means operating automatically when the pressure at the inlet falls below a predetermined level and capable of being manually operated regardless of the pressure at the inlet; and

a tool for bypassing the flow of gas from the outlet to the inlet for filling the gas cylinder with gas where the pressure at the inlet is below the predetermined level, the tool including;

a shaft having a passageway therethrough;

a member at one end of the shaft for engaging the shoulder on the valve plugs, said member being arranged eccentrically with respect to the axis of the shaft;

means for rotating the shaft about its axis;

means for securing the shaft to the outlet and for sealing the resulting junction against leakage of gas; and

means for connecting the shaft to a source of gas for refilling the cylinder;

whereby rotation of the shaft disengages the valve plug from the valve seat.

10. A pressure-responsive check valve system as in claim 9, wherein the means for bypassing includes a second passageway having a second seat and second plug therein, said second plug being arranged to open only when the pressure at the valve outlet exceeds the pressure at the inlet.