US3797263A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dewar filling, purging, and draining system
Assignee: Parker Hannifin Corp
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Filing: 1972-01-07
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Granted: 1974-03-19
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Expires: 1992-01-07
Abstract
Abstract A dewar filling, purging, and draining system characterized in that in the case of servicing of an aircraft dewar containing inerting fluid in liquid form, such as liquid nitrogen (LN2), for use in the aircraft for inerting fuel tanks and the like to prevent fire and explosion, the system is embodied in a mobile vehicle such as a pickup truck with the muffler thereof constituting a heat exchanger to control the saturation pressure of the liquid supplied from the system to the aircraft dewar and to heat gaseous nitrogen (GN2) vented from the system so that no vapor clouds will be visible. The system herein is further characterized in that a single fill hose is employed through which all filling and venting is accomplished, the system and aircraft dewar being provided with pressure switches and the aircraft dewar being provided with liquid level sensors to automatically control the filling and venting functions of the system through electronic controls and valving contained in the system.
Inventors
- 👤 F Shahir
- 👤 W Clarke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:46
CPC Classifications
F; F17; F17C; F17C6/00; F17C9/00; F17C2201/00; F17C2201/01; F17C2201/0104; F17C2201/0109; F17C2205/00; F17C2205/03; F17C2205/0302; F17C2205/0323; F17C2221/00; F17C2221/01; F17C2221/014; F17C2223/00; F17C2223/01; F17C2223/0146; F17C2223/0153; F17C2223/0161; F17C2250/00; F17C2250/04; F17C2250/0404; F17C2250/0408; F17C2260/00; F17C2260/04; F17C2260/042; F17C2270/00; F17C2270/01; F17C2270/0165; F17C2270/0168; F17C2270/05; F17C2270/0509; Y; Y02; Y02E; Y02E60/00; Y02E60/30; Y02E60/32; Y10; Y10T; Y10T137/00; Y10T137/2496; Y10T137/2544
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
132 words
A system for transferring liquid nitrogen from a supply dewar into a receiving dewar comprising fill conduit means having a fill valve therein through which such liquid is conducted from said supply dewar into said receiving dewar; vent conduit means having a vent valve therein through which said receiving dewar is vented to decrease the vapor pressure of the liquid therein; valve operating means responsive to predetermined vapor pressure of the liquid in said receiving dewar to close said fill valve and to open said vent valve thus to decrease such vapor pressure and further responsive to predetermined decreased vapor pressure of the liquid in said receiving dewar to close said vent valve and to open said fill valve to re-establish flow of liquid from said supply dewar into said receiving dewar.
Claim 2
Independent Claim
132 words
A system for transferring liquid nitrogen from a supply dewar into a receiving dewar comprising fill conduit means having a fill valve therein through which such liquid is conducted from said supply dewar into said receiving dewar; vent conduit means having a vent valve therein through which said receiving dewar is vented to decrease the vapor pressure of the liquid therein; valve operating means responsive to predetermined vapor pressure of the liquid in said receiving dewar to close said fill valve and to open said vent valve thus to decrease such vapor pressure and further responsive to predetermined decreased vapor pressure of the liquid in said receiving dewar to close said vent valve and to open said fill valve to re-establish flow of liquid from said supply dewar into said receiving dewar.
Claim 3
Dependent Claim
30 words
The system of claim 1 wherein said vent conduit means has heating means associated therewith effective to heat the vented vapor to prevent cloud formation upon release to the atmosphere.
Claim 4
Dependent Claim
71 words
The system of claim 1 wherein heating means associated with said fill conduit means increases the vapor pressure of the liquid to approximately such predetermined pressure whereby after removal of residual heat in said fill conduit, in said receiving dewar, and in residual liquid therein at the commencement of the transfer operation, the receiving dewar may be filled substantially continuously without alternate opening and closing of said fill and vent valves.
Claim 5
Dependent Claim
30 words
The system of claim 1 wherein said system has pump means effective to cause flow of liquid through said fill conduit means from said supply dewar into said receiving dewar.
Claim 6
Dependent Claim
80 words
The system of claim 4 wherein said pump means comprises pressure buildup conduit means communicating at its opposite ends with the liquid in said supply dewar and with the vapor space thereof and having heating means associated therewith to vaporize the liquid as it flows through said pressure buildup conduit means into such vapor space whereby increased vapor pressure in said supply dewar exceeding such predetermined vapor pressure forces liquid flow through said fill conduit means into said receiving dewar.
Claim 7
Dependent Claim
63 words
The system of claim 5 wherein said pressure buildup conduit means has a solenoid operated valve therein; and wherein a pressure switch responsive to such increased vapor pressure in said supply dewar closes said solenoid operated valve, the latter being cooperatively connected to said valve operating means so that said fill valve can be opened only when said solenoid operated valve is closed.
Claim 8
Dependent Claim
43 words
The system of claim 1 wherein said fill and vent valves are respectively normally closed and normally open solenoid operated valves; and wherein said valve operating means comprises a pressure switch which de-energizes the solenoids of said valves at such predetermined vapor pressure.
Claim 9
Dependent Claim
21 words
The system of claim 7 wherein another pressure switch energizes the solenoids of said valves at such pre-determined decreased vapor pressure.
Claim 10
Independent Claim
123 words
A system for transferring liquid nitrogen from a supply dewar into a receiving dewar comprising conduit means between said dewars having valve means therein through which liquid is conducted from said supply dewar into said receiving dewar and through which said receiving dewar is vented to decrease the vapor pressure of the liquid therein when such pressure exceeds a predetermined value; and valve operating means responsive to such predetermined vapor pressure to operate said valve means to close communication between said dewars and to vent said receiving dewar to the atmosphere and further responsive to predetermined decreased vapor pressure of the liquid in said receiving dewar to open communication between said dewars and to close communication of said receiving dewar with the atmosphere.
Claim 11
Independent Claim
123 words
A system for transferring liquid nitrogen from a supply dewar into a receiving dewar comprising conduit means between said dewars having valve means therein through which liquid is conducted from said supply dewar into said receiving dewar and through which said receiving dewar is vented to decrease the vapor pressure of the liquid therein when such pressure exceeds a predetermined value; and valve operating means responsive to such predetermined vapor pressure to operate said valve means to close communication between said dewars and to vent said receiving dewar to the atmosphere and further responsive to predetermined decreased vapor pressure of the liquid in said receiving dewar to open communication between said dewars and to close communication of said receiving dewar with the atmosphere.
Claim 12
Dependent Claim
46 words
The system of claim 9 wherein said receiving dewar has level sensing means therein effective, upon filling of said receiving dewar to predetermined level, to operate said valve means independently of said valve operating means to close communication between said receiving dewar and said supply dewar.
Claim 13
Dependent Claim
50 words
The system of claim 9 wherein said supply dewar has pressure buildup means associated therewith to cause flow of liquid through said conduit means and valve means into said receiving dewar; and wherein said conduit means has heating means effective to increase the vapor pressure to approximately such predetermined value.
Claim 14
Dependent Claim
27 words
The system of claim 9 wherein said conduit means has heating means effective to heat the vented vapor to prevent cloud formation upon release to the atmosphere.
Claim 15
Dependent Claim
31 words
The system of claim 12 wherein said receiving dewar has a valved drain line through which said receiving dewar may be drained by venting through said conduit means and heating means.
Claim 16
Dependent Claim
34 words
The system of claim 12 wherein said heating means comprises an exhaust muffler of a self-propelled vehicle having said supply dewar and said conduit means adapted to be detachably coupled to said receiving dewar.
Claim 17
Independent Claim
150 words
A system for transferring liquid nitrogen from a supply dewar into a receiving dewar comprising conduit means between said dewars having valve means therein through which liquid is conducted from said supply dewar into said receiving dewar and through which said receiving dewar is vented to decrease the vapor pressure of the liquid therein when such pressure exceeds a predetermined value; and valve operating means responsive to such predetermined vapor pressure to operate said valve means to close communication between said dewars and to vent said receiving dewar to the atmosphere and further responsive to predetermined decreased vapor pressure of the liquid in said receiving dewar to open communication between said dewars and to close communication of said receiving dewar with the atmosphere; said valve operating means comprising first and second pressure sensing means respectively disposed between said valve means and said receiving dewar and downstream of said valve means.
Claim 18
Independent Claim
150 words
A system for transferring liquid nitrogen from a supply dewar into a receiving dewar comprising conduit means between said dewars having valve means therein through which liquid is conducted from said supply dewar into said receiving dewar and through which said receiving dewar is vented to decrease the vapor pressure of the liquid therein when such pressure exceeds a predetermined value; and valve operating means responsive to such predetermined vapor pressure to operate said valve means to close communication between said dewars and to vent said receiving dewar to the atmosphere and further responsive to predetermined decreased vapor pressure of the liquid in said receiving dewar to open communication between said dewars and to close communication of said receiving dewar with the atmosphere; said valve operating means comprising first and second pressure sensing means respectively disposed between said valve means and said receiving dewar and downstream of said valve means.
Claim 19
Dependent Claim
64 words
The system of claim 15 wherein orifice means downstream of said second pressure sensing means and said valve means effects buildup of pressure to such predetermined decreased vapor pressure when said receiving dewar is communicated with the atmosphere via said valve means and orifice means and exposes said second pressure sensing means to atmospheric pressure when said valve means opens communication between said dewars.
Claim 20
Dependent Claim
88 words
The system of claim 16 wherein said receiving dewar has a low level sensing means; and wherein said valve operating means additionally comprises a third pressure sensing means downstream of said valve means operative when the liquid level in said receiving dewar is below said low level sensing means to operate said valve means to oepn communication between said dewars and to close communication of said receiving dewar with the atmosphere when the decreased vapor pressure is less than that to which said second pressure sensing means responds.
Claim 21
Independent Claim
201 words
A system for transferring liquid nitrogen from a supply dewar into a receiving dewar comprising conduit means between said dewars having valve means therein through which Liquid is conducted from said supply dewar into said receiving dewar and through which said receiving dewar is vented to decrease the vapor pressure of the liquid therein when such pressure exceeds a predetermined value; and valve operating means responsive to such predetermined vapor pressure to operate said valve means to close communication between said dewars and to vent said receiving dewar to the atmosphere and further responsive to predetermined decrease vapor pressure of the liquid in said receiving dewar to open communication between said dewars and to close communication of said receiving dewar with the atmosphere; said supply dewar having pressure buildup means associated therewith to cause flow of liquid through said conduit means and valve means into said receiving dewar; said conduit means having heating means effective to increase the vapor pressure to approximately such predetermined value; said heating means comprising a heat exchanger branched off said conduit means to heat a portion of the liquid flowing in said conduit means and to mix it with the remaining portion of the flowing liquid.
Claim 22
Independent Claim
201 words
A system for transferring liquid nitrogen from a supply dewar into a receiving dewar comprising conduit means between said dewars having valve means therein through which Liquid is conducted from said supply dewar into said receiving dewar and through which said receiving dewar is vented to decrease the vapor pressure of the liquid therein when such pressure exceeds a predetermined value; and valve operating means responsive to such predetermined vapor pressure to operate said valve means to close communication between said dewars and to vent said receiving dewar to the atmosphere and further responsive to predetermined decrease vapor pressure of the liquid in said receiving dewar to open communication between said dewars and to close communication of said receiving dewar with the atmosphere; said supply dewar having pressure buildup means associated therewith to cause flow of liquid through said conduit means and valve means into said receiving dewar; said conduit means having heating means effective to increase the vapor pressure to approximately such predetermined value; said heating means comprising a heat exchanger branched off said conduit means to heat a portion of the liquid flowing in said conduit means and to mix it with the remaining portion of the flowing liquid.
Claim 23
Dependent Claim
44 words
The system of claim 18 wherein said system has a valved purge line to conduct liquid heated by said heat exchanger to said receiving dewar while said valve means closes communication between said dewars and closes communication of the receiving dewar with the atmosphere.
Claim 24
Dependent Claim
32 words
The system of claim 19 wherein said receiving dewar has a valved drain line through which the heated liquid in said purge line is adapted to be conducted into said receiving dewar.
Claim 25
Independent Claim
193 words
A system for filling an aircraft dewar with a cryogenic liquid such as LN2 comprising a supply dewar containing LN2; conduit means through which LN2 is conducted from said supply dewar into said aircraft dewar; heating means to increase the vapor pressure of the LN2 flowing through said conduit means into said aircraft dewar; a fill valve in said conduit means through which LN2 flows from said supply dewar into said aircraft dewar when said fill valve is open; pump means operative to force said LN2 to flow through said conduit means into said aircraft dewar when said fill valve is open; a vent valve in said system downstream of said fill valve operative to vent GN2 from said aircraft dewar; heating means operative to heat the vented GN2 to substantially ambient dew point temperature to preclude vapor cloud formation; and valve operating means responsive to increase of vapor pressure in said aircraft dewar to a predetermined maximum to close said fill valve and to open said vent valve and in response to decrease of such vapor pressure to a predetermined minimum to close said vent valve and to open said fill valve.
Claim 26
Independent Claim
193 words
A system for filling an aircraft dewar with a cryogenic liquid such as LN2 comprising a supply dewar containing LN2; conduit means through which LN2 is conducted from said supply dewar into said aircraft dewar; heating means to increase the vapor pressure of the LN2 flowing through said conduit means into said aircraft dewar; a fill valve in said conduit means through which LN2 flows from said supply dewar into said aircraft dewar when said fill valve is open; pump means operative to force said LN2 to flow through said conduit means into said aircraft dewar when said fill valve is open; a vent valve in said system downstream of said fill valve operative to vent GN2 from said aircraft dewar; heating means operative to heat the vented GN2 to substantially ambient dew point temperature to preclude vapor cloud formation; and valve operating means responsive to increase of vapor pressure in said aircraft dewar to a predetermined maximum to close said fill valve and to open said vent valve and in response to decrease of such vapor pressure to a predetermined minimum to close said vent valve and to open said fill valve.
Claim 27
Dependent Claim
69 words
The system of claim 19 wherein said pump means comprises a heat exchanger operative to vaporize a portion of the LN2 in said supply dewar and to conduct GN2 therefrom into the vapor space of said supply dewar thus to apply pressure on the LN2 therein to cause the same to flow through said conduit means into said aircraft dewar via said fill valve when the latter is open.
Claim 28
Dependent Claim
27 words
The system of claim 21 wherein said aircraft dewar has a valved drain conduit means through which said aircraft dewar may be drained vai said heating means.
Claim 29
Dependent Claim
109 words
The system of claim 21 wherein said fill valve is normally closed and wherein said vent valve is normally open; wherein said aircraft dewar has a level sensor therein denoting the full condition thereof and operative to actuate said valve operating means to an inactive position wherein said fill valve is in its normally closed position and said vent valve is in its normally open position; and wherein said conduit means adjacent said aircraft dewar has a shut-off valve therein whereby upon closing of said shut-off valve the portion of said conduit means downstream of said fill valve may be drained by venting through said vent valve as aforesaid.
Claim 30
Dependent Claim
120 words
The system of cLaim 21 wherein said system is embodied in a self-propelled vehicle of the internal combustion engine type having said conduit means adapted to be coupled to a fill line of the aircraft dewar, a portion of said conduit means being disposed in the muffler of said vehicle to constitute said heating means; wherein a branch conduit extends through said muffler to constitute a heat exchanger to heat a portion of the LN2 flowing in said conduit means; and wherein mixing means in said conduit means mixes heated LN2 in said branch conduit with LN2 from said supply dewar to provide a mixture of higher vapor pressure than the vapor pressure of the LN2 in said supply dewar.
Claim 31
Dependent Claim
68 words
The system of claim 25 wherein another branch conduit leading from the downstream side of said heat exchanger means to the portion of said conduit means which is downstream of said fill valve whereby said aircraft dewar and/or aircraft inerting system may be purged with heated GN2 upon opening of a valve in said another branch conduit while both said fill and vent valves are in closed position.
Claim 32
Independent Claim
147 words
A system for transferring liquid nitrogen from a supply dewar into a receiving dewar comprising fill conduit means having a fill valve therein through which such liquid is conducted from said supply dewar into said receiving dewar; vent conduit means branched from said fill conduit means downstream of said fill valve; said vent conduit means having a vent valve therein through which said receiving dewar is vented to decrease the vapor pressure of the liquid therein; valve operating means responsive to predetermined vapor pressure of the liquid in said receiving dewar to close said fill valve and to open said vent valve thus to decrease such vapor pressure and further responsive to predetermined decreased vapor pressure of the liquid in said receiving dewar to close said vent valve and to open said fill valve to re-establish flow of liquid from said supply dewar into said receiving dewar.
Claim 33
Independent Claim
147 words
A system for transferring liquid nitrogen from a supply dewar into a receiving dewar comprising fill conduit means having a fill valve therein through which such liquid is conducted from said supply dewar into said receiving dewar; vent conduit means branched from said fill conduit means downstream of said fill valve; said vent conduit means having a vent valve therein through which said receiving dewar is vented to decrease the vapor pressure of the liquid therein; valve operating means responsive to predetermined vapor pressure of the liquid in said receiving dewar to close said fill valve and to open said vent valve thus to decrease such vapor pressure and further responsive to predetermined decreased vapor pressure of the liquid in said receiving dewar to close said vent valve and to open said fill valve to re-establish flow of liquid from said supply dewar into said receiving dewar.
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) | 1977-03-18 | 1977-09-17 | 1978-03-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-18 | 1981-09-17 | 1982-03-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-18 | 1985-09-17 | 1986-03-19 | $7700.00 | Window Closed / Lapsed |