Extremely fast freezing, low-temperature blast freezer

Patent metadata

Field	Value
Publication number	US-10660328-B2
Application number	US-201816112658-A
Country	US
Kind code	B2
Filing date	Aug 25, 2018
Priority date	May 12, 2009
Publication date	May 26, 2020
Grant date	May 26, 2020

Abstract

A freezer includes a plurality of shelves in an insulated payload bay; a plurality of evaporators coupled to the payload bay with a multiplicity of coolant tubes in each evaporator, wherein each tube enters and then exits the payload bay, further comprising one or more cryogenic valves coupled to the coolant tubes; a pump to force coolant flowing through the evaporators with a pressure of at least 90 psi to supply the coolant at each evaporator with at least 80 gallons per hour of coolant; and a plurality of fans to circulate cooled air in the payload bay.

First claim

The invention claimed is:

1. A system, comprising:
a plurality of shelves in a payload bay surrounded by insulation acting as a thermal barrier between the payload bay and the outside environment;
a plurality of evaporators coupled to the payload bay with a multiplicity of coolant tubes in each evaporator, wherein the coolant tubes cool the payload bay in parallel, further comprising one or more cryogenic solenoid valves coupled to the coolant tubes;
a liquid nitrogen source to circulate a predetermined amount of coolant at a predetermined pressure to drive a predetermined coolant flow through the plurality of evaporators with coolant tubes and cool the payload bay to −150 degree Celsius in one hour;
a thermal barrier isolating thermal flow between the payload bay and a main door where the thermal barrier comprises a gap with a non-metal material attached to both sides of the gap;
an inner door and a pneumatic seal providing an airtight seal between the main door and the payload bay;
a plurality of fans to circulate convective cooled air in the payload bay; and
an external fan that forces air through a room heat exchanger.

2. The system of claim 1 , comprising one or more vent holes placed at predetermined locations on the payload bay.

3. The system of claim 1 , comprising a separate compartment located between the payload bay and the outside environment with an insulation of between 2 and 4 inches thick.

4. The system of claim 1 , comprising a controller coupled to a thermocouple inside the payload bay.

5. The system of claim 4 , wherein the controller performs proportional-integral-derivative (PID) control to maintain a set point within a predetermined limit.

6. The system of claim 1 , wherein the one or more cryogenic solenoid valves are located at an exhaust port.

7. The system of claim 1 , comprising one or more heating tubes within one or more evaporators.

8. The system of claim 1 , comprising a mechanical valve located in parallel with one or more cryogenic solenoid valves to manually regulate payload bay temperature.

9. The system of claim 1 , comprising a battery to provide backup power.

10. The system of claim 1 , wherein a safety valve is connected to one or more coolant tubes.

11. The system of claim 10 , wherein the safety valve has one or more heating fins or electrical heat tape coupled to it.

12. The system of claim 1 , comprising one or more pneumatic latches.

13. The system of claim 12 , wherein the one or more pneumatic latches and a rubber pneumatic seal are powered by gaseous nitrogen.

14. A system, comprising:
a liquid nitrogen inlet to receive liquid nitrogen;
one or more coolant tubes that operate at a predetermined liquid nitrogen pressure;
a payload bay;
one or more evaporators inside the payload bay;
one or more fans that distribute cooled air from the one or more evaporators to the payload bay;
one or more vent holes;
insulation surrounding the payload bay;
a controller that maintains a temperature set point for the payload bay;
a thermal barrier isolating thermal flow between the payload bay and a main door where the thermal barrier comprises a gap with a non-metal material attached to both sides of the gap;
an inner door and a pneumatic seal providing an airtight seal between the main door and the payload bay;
one or more pneumatic latches to secure a main door; and
a rubber pneumatic seal that provides an airtight seal for the payload bay and the main door.

Assignees

• Tran Bao
• Reflect Scient Inc

Inventors

• Moon William G
• Hancock William J
• Boyce Steven V
• Parkinson Steven J

Classifications

• F25D17/06

  by forced circulation · CPC title

• F25D29/001

  for cryogenic fluid systems · CPC title

• F25D3/102

  Stationary cabinets · CPC title

• F25D2700/122

  of freezer compartments · CPC title

• F25D29/006

  Safety devices · CPC title