Closed cycle cryogenic refrigeration system with automatic variable flow area throttling device
US5595065A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 7, 1995 |
| Grant date | Jan 21, 1997 |
| Priority date | — |
| Expiry date | Jul 7, 2015 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF25B2400/12
- WIPO fieldThermal processes and apparatus
- WIPO sectorMechanical engineering
Abstract
An integral combination of expansion valve and evaporator in a cryostat using a single support member. The valve includes two flow orifices, one orifice being used primarily for steady-state operation and the other orifice being used only during cool-down. An actuator having a high coefficient of thermal expansion moves a needle positioned in the cool-down orifice such that a large orifice flow area at the start of cool-down is automatically and continuously reduced as the actuator temperature decreases as refrigerant is throttled through the orifice. Within a range of approximately 30 K from the desired steady-state evaporator temperature, the needle completely blocks the cool-down orifice. Then, refrigerant flows through the steady-state orifice which has a remotely adjustable needle. In the final stage of cool-down, the refrigerant system is entirely controlled by the steady-state orifice and its associated needle. In other embodiments, the steady-state orifice and adjusting needle, are replaced with a fixed restrictor, such as a capillary tube, that is positioned in parallel with the cool-down orifice and needle. The fixed restrictor is sized to satisfy the desired steady-state…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.