US3673810A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Liquid nitrogen refrigeration system
Assignee: SHIPOWNERS CARGO RES ASSOC
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Filing: 1970-10-26
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Granted: 1972-07-04
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Expires: 1990-10-26
Abstract
Abstract The invention relates generally to apparatus for controlling the pressure of fluid supplied from a pressure source to a valve to open and close the valve for predetermined time intervals, the valve preferably being provided in a pipe leading from a supply of liquid nitrogen to the interior of a refrigerated cargo container to condition the interior of the container by supplying pulses of liquid nitrogen for said predetermined time intervals. The apparatus includes a fluidic logic arrangement in a closed loop with a fluidic delay unit, both the fluidic logic arrangement and the delay unit being powered by said pressure source nitrogen vapor and the fluidic logic arrangement has an output port adapted to be connected to the valve, a starter preferably connected to the pressure source to provide a fluidic pressure output starting signal to the fluidic logic arrangement, after which, in a cycle of operations, said fluidic logic arrangement delivers a fluidic pressure input to the fluidic delay unit and an output at said port for opening the valve, the delay unit causing a fluidic output to be delivered to the input of said fluidic logic arrangement after a predetermined time for closing the valve, which output delivered to the input of the fluidic logic arrangement also automatically resets the apparatus continuously to repeat the cycle.
Inventors
- 👤 Kenneth Calvert Hales
- 👤 Gerald Robin Scrine
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:23
CPC Classifications
F; F25; F25D; F25D3/00; F25D3/10; F25D3/105; F25D29/00; F25D29/001; Y; Y10; Y10T; Y10T137/00; Y10T137/206; Y10T137/2065; Y10T137/2071
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
168 words
In combination, a cargo container, a reservoir containing a supply of liquid nitrogen, meanS including a valve for connecting said reservoir with the interior of said container, and fluidic control apparatus for controlling the supply of nitrogen to said container by opening and closing the valve for predetermined time intervals, said control apparatus comprising a fluidic logic arrangement in a closed loop with a fluidic delay unit, both the fluid logic unit and the delay unit being powered by pressure in the reservoir, means connecting an output of the fluidic logic arrangement to said valve, a starter powered from the nitrogen reservoir to provide a fluidic pressure starting signal to the fluidic logic arrangement, whereby in a cycle of operations, said fluidic logic arrangement delivers an input to said delay unit and opens said valve, said delay unit causing an input to be delivered to said fluidic logic arrangement after a predetermined time, thereby closing the valve, and also automatically resetting the control apparatus to repeat the cycle.
Claim 2
Dependent Claim
168 words
In combination, a cargo container, a reservoir containing a supply of liquid nitrogen, meanS including a valve for connecting said reservoir with the interior of said container, and fluidic control apparatus for controlling the supply of nitrogen to said container by opening and closing the valve for predetermined time intervals, said control apparatus comprising a fluidic logic arrangement in a closed loop with a fluidic delay unit, both the fluid logic unit and the delay unit being powered by pressure in the reservoir, means connecting an output of the fluidic logic arrangement to said valve, a starter powered from the nitrogen reservoir to provide a fluidic pressure starting signal to the fluidic logic arrangement, whereby in a cycle of operations, said fluidic logic arrangement delivers an input to said delay unit and opens said valve, said delay unit causing an input to be delivered to said fluidic logic arrangement after a predetermined time, thereby closing the valve, and also automatically resetting the control apparatus to repeat the cycle.
Claim 3
Dependent Claim
151 words
A combination according to claim 1, in which the control apparatus includes a pair of closed loops each provided with a NOR unit and a fluidic delay unit in series, the two NOR units being cross connected to provide a flip-flop and operation of the apparatus being started by application of an input to the NOR unit of one of the loops whereby, due to the cross connection of the NOR units, a fluid input is maintained at the NOR unit of the said one loop and is delivered to the delay unit of the other loop and to the output connectable to the valve for opening the valve whereby, after said predetermined time interval, said delay unit resets the flip-flop, thus closing the valve, and deliverinG an input to the delay unit of said one loop, which after said predetermined time delay, reconditions the flip-flop automatically to repeat the cycle.
Claim 4
Dependent Claim
50 words
A combination according to claim 2, in which each of the closed loops is provided with an even number of further NOR units, each having an associated series connected restrictor and volume and connected in series with the first NOR unit in each loop to provide the fluidic delay unit.
Claim 5
Dependent Claim
47 words
A combination according to claim 3, in which a multiport valve is provided in at least one of the closed loops, so as to alter the time interval by switching into the said at least one loop a further even number of NOR units, restrictors and volumes.
Claim 6
Dependent Claim
101 words
A combination according to claim 1, in which the fluid logic aRrangement comprises a NOR unit and the fluidic delay unit comprises an even number of further NOR units arranged in series with the fluidic logic arrangement, each NOR unit being in series with a restrictor and a volume and each NOR unit being powered by the pressure source, the arrangement being such that the last volume in the loop is alternately vented so that there is no input to the fluidic logic arrangement and closed so that a pressure builds up to give an input to the fluidic logic arrangement.
Claim 7
Dependent Claim
32 words
A combination according to claim 5, including further pairs of NOR units and a multiport valve for switching said further pairs of NOR units into the loop to alter the time intervals.
Claim 8
Dependent Claim
74 words
A combination according to claim 1, in which the fluidic pressure input starting signal is provided by stop/start elements, the stop and start elements being connectable to the reservoir and each having outputs connected to an input of a further NOR unit, each of these further NOR units being cross connected to provide a simple flip-flop, whereby there is a continuous output from the flip-flop to the loop until the stop element is operated.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-07-04 | 1976-01-03 | 1976-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-04 | 1980-01-03 | 1980-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-04 | 1984-01-03 | 1984-07-04 | $7700.00 | Window Closed / Lapsed |