US4589566A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pressure responsive safety interlock
Assignee: Robbins and Myers Energy Systems LP
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Filing: 1985-04-08
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Granted: 1986-05-20
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Expires: 2005-04-08
Abstract
Abstract A safety interlock device is provided for preventing the opening of a vessel containing a pressurized fluid. In a typical application, the interlock device may be used in industrial applications to prevent the inadvertent unscrewing of a cap from the end of a large pressure vessel containing a hazardous gas. A pressure port end of the interlock body is adapted for threaded engagement with the vessel and is open to vessel pressure. A pressure-responsive locking piston movable within the body prohibits removal of a stem when vessel pressure exceeds a selected minimum pressure. A chain may be secured at each end to the stem and vessel cap, so that the cap cannot be unscrewed to open the container unless the stem is first removed. In one embodiment, the locking piston is prevented from manual override by the position of a second piston and a plurality of ball members locked in a groove.
Inventors
- 👤 Joe F. Rives
- 👤 Forrest L. Carson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:45
CPC Classifications
F; F16; F16J; F16J13/00; F16J13/24; B; B01; B01J; B01J3/00; B01J3/002
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
223 words
A safety interlock device responsive to fluid pressure within a vessel for preventing unthreading of a vessel cap when said vessel contains a fluid under pressure, said interlock device comprising: an interlock body having an entrance port for fluid communication with said fluid in said vessel, a piston chamber, and a stem port opposite said entrance port with respect to said piston chamber; an elongate stem at least partially positionable within and axially removable from said interlock body; stop means for limiting movement of said vessel cap relative to said stem to prevent unthreading of said vessel cap unless said stem is removed from said interlock body; a piston movable independent of said stem within said piston chamber and responsive to said fluid pressure for moving from an unlock position to a lock position, said piston having a stem passageway for receiving a portion of said stem; said interlock body having a fluid passageway for establishing fluid communication between said entrance port and said piston chamber, and a portion of said fluid passageway defining a seating surface; a valve member carried by said stem for sealing engagement with said seating surface for controlling fluid flow through said fluid passageway; and said stem including a shoulder for engagement with said piston in said lock position to prevent removal of said stem from said body.
Claim 2
Dependent Claim
223 words
A safety interlock device responsive to fluid pressure within a vessel for preventing unthreading of a vessel cap when said vessel contains a fluid under pressure, said interlock device comprising: an interlock body having an entrance port for fluid communication with said fluid in said vessel, a piston chamber, and a stem port opposite said entrance port with respect to said piston chamber; an elongate stem at least partially positionable within and axially removable from said interlock body; stop means for limiting movement of said vessel cap relative to said stem to prevent unthreading of said vessel cap unless said stem is removed from said interlock body; a piston movable independent of said stem within said piston chamber and responsive to said fluid pressure for moving from an unlock position to a lock position, said piston having a stem passageway for receiving a portion of said stem; said interlock body having a fluid passageway for establishing fluid communication between said entrance port and said piston chamber, and a portion of said fluid passageway defining a seating surface; a valve member carried by said stem for sealing engagement with said seating surface for controlling fluid flow through said fluid passageway; and said stem including a shoulder for engagement with said piston in said lock position to prevent removal of said stem from said body.
Claim 3
Dependent Claim
28 words
An interlock device as defined in claim 1, further comprising: stem sealing means between said stem and said body for prohibiting loss of fluid pressure from said body.
Claim 4
Dependent Claim
37 words
An interlock device as defined in claim 2, further comprising: said body including a threaded fluid entrance portion for threaded engagement with said vessel; and said stem includes a threaded portion for threaded engagement with said body.
Claim 5
Dependent Claim
27 words
An interlock device as defined in claim 2, wherein said seating surface and said stem port are each axially aligned with said elongate stem in said body.
Claim 6
Dependent Claim
33 words
An interlock device as defined in claim 1, further comprising: a piston stop for limiting rotation of said piston relative to said body; and piston sealing means between said piston and said body.
Claim 7
Dependent Claim
62 words
An interlock device as defined in claim 1, further comprising: an external end cap defining a portion of said piston chamber and having an aperture for receiving an indicator portion of said piston; and said indicator portion of said piston projecting from said end cap when said piston is in a lock position as a visual indication of pressure within said vessel.
Claim 8
Dependent Claim
21 words
A safety interlock device as defined in claim 3, wherein said stem passageway has a slightly larger cross-section than said shoulder.
Claim 9
Dependent Claim
24 words
A safety interlock device as defined in claim 1, wherein said stop means comprises a chain for connecting said stem and said vessel cap.
Claim 10
Dependent Claim
37 words
A safety interlock device as defined in claim 1, wherein said step means comprises a stop member rigidly affixed to said vessel cap for engagement with said stem when said stem is positioned within said interlock body.
Claim 11
Dependent Claim
40 words
An interlock device as defined in claim 2, further comprising: a solid end cap defining a portion of said piston chamber; and biasing means between said end cap and said piston for automatically biasing said piston towards said unlock position.
Claim 12
Dependent Claim
162 words
A safety interlock device responsive to fluid pressure in a vessel for preventing opening of a vessel cap when said vessel contains a fluid under at least a nominal pressure, comprising: an interlock body having an entrance port for fluid communication with said fluid in said vessel, a piston chamber, and a stem port; a stem positionable at least partially within and axially removable from said interlock body; stop means for limiting movement of said vessel cap relative to said stem to prevent opening of said vessel cap unless said stem is removed from said interlock body; a piston movable independent of said stem within said piston chamber and responsive to said fluid pressure for moving from an unlock position to a lock position, said piston having a stem passageway for receiving a portion of said stem; and said stem including a shoulder portion for engagement with said piston in said lock position to prevent removal of said stem from said body.
Claim 13
Dependent Claim
162 words
A safety interlock device responsive to fluid pressure in a vessel for preventing opening of a vessel cap when said vessel contains a fluid under at least a nominal pressure, comprising: an interlock body having an entrance port for fluid communication with said fluid in said vessel, a piston chamber, and a stem port; a stem positionable at least partially within and axially removable from said interlock body; stop means for limiting movement of said vessel cap relative to said stem to prevent opening of said vessel cap unless said stem is removed from said interlock body; a piston movable independent of said stem within said piston chamber and responsive to said fluid pressure for moving from an unlock position to a lock position, said piston having a stem passageway for receiving a portion of said stem; and said stem including a shoulder portion for engagement with said piston in said lock position to prevent removal of said stem from said body.
Claim 14
Dependent Claim
29 words
A safety interlock device as defined in claim 11, further comprising: stem sealing means between said stem and said body for prohibiting loss of fluid pressure from said body.
Claim 15
Dependent Claim
22 words
A safety interlock device as defined in claim 12, wherein said stem includes a threaded portion for threaded engagement with said body.
Claim 16
Dependent Claim
63 words
A safety interlock device as defined in claim 11, further comprising: an external end cap defining a portion of said piston chamber and having an aperture for receiving an indicator portion of said piston; and said indicator portion of said piston projecting from said end cap when said piston is in a lock position as a visual indication of pressure within said vessel.
Claim 17
Dependent Claim
82 words
A safety interlock device as defined in claim 11, further comprising: said interlock body having a fluid passageway for establishing fluid communication between said entrance port and said piston chamber, and a portion of said fluid passageway defining a seating surface; a valve member carried by said stem for sealing engagement with said seating surface for controlling fluid flow through said fluid passageway; and said seating surface and said stem port are each axially aligned with said elongate stem in said body.
Claim 18
Dependent Claim
59 words
A safety interlock device as defined in claim 10, further comprising: said piston having an effective cross-sectional area responsive to said fluid pressure of at least 2.5 square inches; a piston rotation stop for limiting rotation of said piston relative to said body; and a piston axial stop for limiting axial movement of said piston in said unlock position.
Claim 19
Dependent Claim
207 words
A safety interlock device responsive to fluid pressure in a vessel for preventing the opening of a vessel cap when said vessel contains fluid under pressure, said interlock device comprising: an interlock body having an entrance port for fluid communication with fluid pressure in said vessel, a piston chamber, and a stem port; an elongate stem for positioning at least partially within and axially removable from said interlock body; stop means for limiting movement of said vessel cap relative to said stem to prevent opening of said cap unless said stem is removed from said interlock body; a first piston movable independent of said stem and responsive to said fluid pressure for moving from an unlock position to a lock position, said piston having a stem passageway for receiving a portion of said stem; a second piston movable relative to both said first piston and said interlock body in response to fluid pressure; a first piston stop operationally responsive to a position of said second piston relative to said interlock body for prohibiting movement of said first piston to said unlock position; and said stem including a shoulder portion for engagement with said piston in said lock position to prevent removal of said stem from said body.
Claim 20
Dependent Claim
207 words
A safety interlock device responsive to fluid pressure in a vessel for preventing the opening of a vessel cap when said vessel contains fluid under pressure, said interlock device comprising: an interlock body having an entrance port for fluid communication with fluid pressure in said vessel, a piston chamber, and a stem port; an elongate stem for positioning at least partially within and axially removable from said interlock body; stop means for limiting movement of said vessel cap relative to said stem to prevent opening of said cap unless said stem is removed from said interlock body; a first piston movable independent of said stem and responsive to said fluid pressure for moving from an unlock position to a lock position, said piston having a stem passageway for receiving a portion of said stem; a second piston movable relative to both said first piston and said interlock body in response to fluid pressure; a first piston stop operationally responsive to a position of said second piston relative to said interlock body for prohibiting movement of said first piston to said unlock position; and said stem including a shoulder portion for engagement with said piston in said lock position to prevent removal of said stem from said body.
Claim 21
Dependent Claim
47 words
An interlock device as defined in claim 17, wherein said first piston stop comprises a plurality of ball members radially movable from a position extending outward of an exterior surface of said first piston to a position extending inward of an inner surface of said first piston.
Claim 22
Dependent Claim
61 words
A safety interlock device as defined in claim 17, further comprising: said interlock body having fluid passageway for establishing communication between said entrance port and said piston chamber, and a portion of said fluid passageway defining a seating surface; a valve member carried by said stem for sealing engagement with said seating surface for controlling fluid flow through said fluid passageway.
Claim 23
Dependent Claim
30 words
A safety interlock device as defined in claim 19, further comprising: stem sealing means between said valve member and said body for prohibiting loss of fluid pressure from said body.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-05-19 | 1989-11-18 | 1990-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-05-19 | 1993-11-18 | 1994-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-05-19 | 1997-11-18 | 1998-05-20 | $7700.00 | Window Closed / Lapsed |