US3812816A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Differential pressure indicator with internal reset
Assignee: Parker Hannifin Corp
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Filing: 1972-03-01
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Granted: 1974-05-28
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Expires: 1992-03-01
Abstract
Abstract A differential pressure indicator is described in which a pressure sensitive means is arranged to respond to an increase in differential pressure within a fluid system. This means is operatively associated with an indicator which provides a signal when the differential pressure in the fluid system exceeds a set limit. At this point, the pressure sensitive means is locked in place and neither the indicator signal or the pressure sensitive means can be reset until the cause of the increased differential pressure is corrected. A thermally sensitive element is incorporated in the pressure sensitive means to prevent false pressure responses when the fluid may be in a more viscous state at low temperature.
Inventors
- 👤 C Juhasz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 03:38
CPC Classifications
B; B01; B01D; B01D35/00; B01D35/14; B01D35/143; G; G01; G01L; G01L19/00; G01L19/08; G01L19/12; G01L7/00; G01L7/16; G01L7/163
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
203 words
A temperature sensitive differential pressure indicating device comprising: a. a hollow housing having a chamber formed therein; b. an indicator means located at one end of said housing and including an indicating member movable between a non-indicating position and an indicating position; c. a piston disposed within said chamber and movable between a first position and a second position, biasing means for urging said piston towards said first position, and said chamber having openings therein for transmission of differential fluid pressure to said piston for moving said piston toward said second position; d. a first locking means for locking said piston in said first position, said first locking means including temperature sensitive means operative below a predetermined temperature for holding said piston immovable within said chamber and operative above said predetermined temperature to release said piston for movement within said chamber to said second position; e. a second locking means for locking said piston in said second position; f. a first holding means for hOlding said indicator member in its non-indicating position when said piston is in its first position; and g. a second holding means for holding said indicator member in its indicating position when said piston is in its second position.
Claim 2
Dependent Claim
203 words
A temperature sensitive differential pressure indicating device comprising: a. a hollow housing having a chamber formed therein; b. an indicator means located at one end of said housing and including an indicating member movable between a non-indicating position and an indicating position; c. a piston disposed within said chamber and movable between a first position and a second position, biasing means for urging said piston towards said first position, and said chamber having openings therein for transmission of differential fluid pressure to said piston for moving said piston toward said second position; d. a first locking means for locking said piston in said first position, said first locking means including temperature sensitive means operative below a predetermined temperature for holding said piston immovable within said chamber and operative above said predetermined temperature to release said piston for movement within said chamber to said second position; e. a second locking means for locking said piston in said second position; f. a first holding means for hOlding said indicator member in its non-indicating position when said piston is in its first position; and g. a second holding means for holding said indicator member in its indicating position when said piston is in its second position.
Claim 3
Dependent Claim
30 words
A device according to claim 1 in which said piston has a head adjacent to said indicator member, said first holding means comprising a magnet carried by said piston head.
Claim 4
Dependent Claim
30 words
A device according to claim 1 in which said second holding means comprises an indicator magnet located adjacent to said indicator member on a side thereof remote from said piston.
Claim 5
Dependent Claim
116 words
A device according to claim 1 wherein said piston has a cavity formed therein and is provided with at least one opening communicating with said cavity, said temperature sensitive means being positioned within said cavity and including a head, said housing having slot means formed interiorly thereof, detent means contained within said opening and held in said slot means by said head for locking said piston in said first position, notch means formed in said head, and means for rotating said head within said cavity for aligning said notch means with said detent means to allow said detent means to move out of said slot means and release said piston for movement to said second position.
Claim 6
Dependent Claim
148 words
A device according to claim 1 in which said second locking means comprises a sleeve surrounding said hollow housing in sliding relationship therewith, said sleeve having a cavity means formed interiorly thereof for engagement with at least one detent means, said chamber having a wall and an opening formed in the wall, said detent means being located within said opening, said piston having a slot means formed exteriorly thereon for partially receiving said detent means when said piston is in its second position, said sleeve having an initial position and a final position and biasing means for urging said sleeve towards said final position, said sleeve being retained in its final position by engagement with fixed pin means on said housing, said sleeve in said final position locking said piston in its second position by holding said detent means in said slot means formed exteriorly on said piston.
Claim 7
Dependent Claim
73 words
A device according to claim 1 werein said indicator member includes magnetically attractable material, a cavity located at one end of said housing and being defined by a wall member at one end and a flexible transparent dome at a second end, magnet means located within said cavity in spaced relation to said wall member, said indicator member being located within said cavity and movable between said wall member and said magnet means.
Claim 8
Dependent Claim
202 words
A temperature responsive device for controlling relative movement between first and second members, said first member including an opening extending therethrough; detent means located within said opening and having a portion partially protruding therefrom, said second member being disposed adjacent to said first member; slot means formed in said second member, said slot means being disposed in alignment with said opening and receiving said portion of said detent means; a temperature responsive element disposed adjacent to said first member on a side thereof remote from said second member and including a head disposed adjacent to said opening for holding said detent means within said opening and partially within said slot means; notch means formed within said head at a portion thereof remote from said opening; and means for rotating said head in response to a change in ambient temperature for locating said notch means adjacent to said opening; means for moving said portion of said detent means out of said slot means for locating said detent means in said opening and partially within said notch means; and means for causing relative movement between said first and second members upon movement of said portion of said detent means out of said slot means.
Claim 9
Dependent Claim
202 words
A temperature responsive device for controlling relative movement between first and second members, said first member including an opening extending therethrough; detent means located within said opening and having a portion partially protruding therefrom, said second member being disposed adjacent to said first member; slot means formed in said second member, said slot means being disposed in alignment with said opening and receiving said portion of said detent means; a temperature responsive element disposed adjacent to said first member on a side thereof remote from said second member and including a head disposed adjacent to said opening for holding said detent means within said opening and partially within said slot means; notch means formed within said head at a portion thereof remote from said opening; and means for rotating said head in response to a change in ambient temperature for locating said notch means adjacent to said opening; means for moving said portion of said detent means out of said slot means for locating said detent means in said opening and partially within said notch means; and means for causing relative movement between said first and second members upon movement of said portion of said detent means out of said slot means.
Claim 10
Dependent Claim
53 words
A temperature responsive device according to claim 7 including a shank attached to said head, said means for rotatiNg said head comprising a bi-metallic strip encircling said shank, said strip having first and second ends, said first end being attached to said first member and said second end being attached to said shank.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-05-27 | 1977-11-26 | 1978-05-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-27 | 1981-11-26 | 1982-05-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-27 | 1985-11-26 | 1986-05-28 | $7700.00 | Window Closed / Lapsed |