Refrigeration system having a modulation valve which also performs function of compressor throttling valve
US4977751A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 28, 1989 |
| Grant date | Dec 18, 1990 |
| Priority date | — |
| Expiry date | Dec 28, 2009 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF25B2600/026
- WIPO fieldThermal processes and apparatus
- WIPO sectorMechanical engineering
Abstract
A refrigeration system having a modulation valve which controls refrigerant flow to a compressor according to a control algorithm. The need for a compressor throttling valve is eliminated by a load control circuit which operates the modulation valve to perform the function of the throttling valve when load reduction is required. An overload condition of a compressor prime mover overrides the control algorithm and selects a predetermined load control position of the modulation valve. A timer ensures that a predetermined recovery time is provided, before switching back to the control algorithm. The timer also selects the load control position of the modulation valve upon start-up. A heating or defrost mode automatically selects the load control position of the modulation valve for the duration of the mode, as does an ambient air temperature sensor when the ambient exceeds a predetermined value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.