Liquid cryogen freezer with improved vapor balance control
US4947654A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 30, 1989 |
| Grant date | Aug 14, 1990 |
| Priority date | — |
| Expiry date | Nov 30, 2009 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB65G2207/24
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
A cryogenic freezer apparatus for food products includes a conveyor within a thermally insulated enclosure. A cryogen injecting unit is located in said enclosure adjacent the opening thereof, and responsive to a cryogen control signal for introducing liquid cryogen in said enclosure. A blower unit in said enclosure directs cryogen vapor away from said enclosure opening toward the interior of said enclosure. The output of said blower unit being controllable by a blower control signal. A sensing unit within said enclosure senses the cooling capacity of the cryogen vapor at the enclosure opening and generates a sensor output signal which is indicative of the amount of cryogen vapor escaping out of said opening. A control unit, coupled to said sensing unit, said injecting unit, and to said blower unit generates a cryogen control signal and a blower control signal in response to the sensor output signal. Cryogen vapor escaping from the enclosure is limited to an amount needed to maintain an air lock, thus preventing air intrusion into the enclosure.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.