Patent US3866432A successfully refreshed from Google Patents.
US3866432A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Helical conveyor heat exchange system
Assignee: Cryo Chem Inc
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Filing: 1973-03-29
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Granted: 1975-02-18
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Expires: 1993-03-29
Abstract
Abstract Food is frozen in a high temperature gradient environment by moving the food along a helical conveyor countercurrently to a fan-driven stream of cold nitrogen gas produced by contacting liquid nitrogen with the food near the discharge end of the conveyor. The food at the discharge end of the conveyor is subjected to about -320* F, the boiling point of nitrogen at atmospheric pressure. Before leaving the freezer, the nitrogen gas is warmed substantially above that temperature by contact with the food on the helical conveyor.
Inventors
- 👤 Donald I Harrison
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:01
CPC Classifications
F; F25; F25D; F25D3/00; F25D3/10; F25D3/11; F25D25/00; F25D25/04
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
216 words
Cooling apparatus comprising a thermally insulated enclosure with an inlet and an outlet for material to be cooled, the inlet being below the outlet, a helical conveyor having upper and lower ends disposed in the enclosure about an upright axis to carry the material upwardly from the inlet to the outlet of the enclosure, an upright annular and imperforate baffle disposed within the helical convevyor, means for introducing liquid nitrogen into the enclosure to contact the material on the conveyor at a point nearer the enclosure outlet than the inlet so the liquid nitrogen absorbs sufficient heat to vaporize to nitrogen gas, fan means in the enclosure arranged to impart a horizontal velocity vector component to the nitrogen gas thus blowing it around the helical conveyor in the direction opposite to that in which the material is moved on the conveyor, means for creating a lower pressure at the lower end of the helical conveyor than at the upper end so that a vertical velocity vector component is imparted to the gas so that substantially all the nitrogen gas flows down the helical conveyor, the net flow of the gas being to spiral downwardly around the helix to effect countercurrent cooling of material with the nitrogen gas, and means for removing nitrogen gas from the enclosure.
Claim 2
Dependent Claim
216 words
Cooling apparatus comprising a thermally insulated enclosure with an inlet and an outlet for material to be cooled, the inlet being below the outlet, a helical conveyor having upper and lower ends disposed in the enclosure about an upright axis to carry the material upwardly from the inlet to the outlet of the enclosure, an upright annular and imperforate baffle disposed within the helical convevyor, means for introducing liquid nitrogen into the enclosure to contact the material on the conveyor at a point nearer the enclosure outlet than the inlet so the liquid nitrogen absorbs sufficient heat to vaporize to nitrogen gas, fan means in the enclosure arranged to impart a horizontal velocity vector component to the nitrogen gas thus blowing it around the helical conveyor in the direction opposite to that in which the material is moved on the conveyor, means for creating a lower pressure at the lower end of the helical conveyor than at the upper end so that a vertical velocity vector component is imparted to the gas so that substantially all the nitrogen gas flows down the helical conveyor, the net flow of the gas being to spiral downwardly around the helix to effect countercurrent cooling of material with the nitrogen gas, and means for removing nitrogen gas from the enclosure.
Claim 3
Dependent Claim
73 words
Apparatus according to claim 1 which includes a first manifold for spraying a portion of the liquid nitrogen on the product on the conveyor at the point nearer the enclosure outlet than the inlet, and a second manifold for spraying the balance of the liquid nitrogen onto the product at another point farther from the enclosure outlet than where the first manifold is located, but closer to the enclosure outlet than the inlet.
Claim 4
Dependent Claim
32 words
Apparatus according to claim 2 which includes means for varying the amount of liquid nitrogen supplied through the second manifold while maintaining substantially constant flow of liquid nitrogen through the first manifold.
Claim 5
Dependent Claim
32 words
Apparatus according to claim 3 which includes means responsive to the temperature of the vaporized nitrogen removed from the enclosure for controlling the amount of liquid nitrogen flowing through the second manifold.
Claim 6
Dependent Claim
31 words
Apparatus according to claim 1 which includes a sump in the floor of the enclosure for collecting excess liquid nitrogen, and vaporizing means in the sump for vaporizing liquid collected there.
Claim 7
Dependent Claim
36 words
Apparatus according to claim 5 which includes a sensor in the sump for detecting the presence of liquid nitrogen, and means responsive to the sensor for shutting off the flow of liquid nitrogen into the enclosure.
Claim 8
Dependent Claim
16 words
Apparatus according to claim 5 which includes means repsponsive to the sensoR for stopping the convyor.
Claim 9
Dependent Claim
30 words
Apparatus according to claim 5 which includes a sensor in the sump for detecting the present of liquid nitrogen, and means responsive to the sensor for energizing the vaporizing means.
Claim 10
Dependent Claim
85 words
Apparatus according to claim 8 which includes a first sensor at one level in the sump for developing a signal when liquid accumulates in the sump, means responsive to the signal from the first sensor for energizing the vaporizer, a second sensor disposed about the first sensor for detecting the presence of liquid in the sump at a level above that of the first sensor, and means responsive to the signal from the first sensor for stopping the flow of liquid nitrogen into the enclosure.
Claim 11
Dependent Claim
20 words
Apparatus according to claim 9 which includes means responsive to the signal from the second sensor for stopping the conveyor.
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) | 1978-02-17 | 1978-08-19 | 1979-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-17 | 1982-08-19 | 1983-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-17 | 1986-08-19 | 1987-02-18 | $7700.00 | Window Closed / Lapsed |