Apparatus for controlling condenser pressure in a refrigeration system
US4075865A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 5, 1975 |
| Grant date | Feb 28, 1978 |
| Priority date | — |
| Expiry date | Dec 5, 1995 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S388/934
- WIPO fieldThermal processes and apparatus
- WIPO sectorMechanical engineering
Abstract
Constant condenser pressure is maintained in a refrigeration system by modulating the speed of at least one fan motor of an air-cooled condenser coil in response to the temperature of the refrigerant in the condenser coil, the speed varying directly with temperature. Motor speed variations are achieved by controlling the conduction time of a triac which couples the fan motor to a source of alternating voltage. The triac is triggered into conduction at a phase angle, following the beginning of each half cycle of the alternating voltage, determined by the charging rate of a timing capacitor which charges through a photosensitive transistor optically coupled to an LED. Variation of the refrigerant temperature in the condenser coil changes the light emission of the LED and this in turn varies the charging current translated to the capacitor. The greater the temperature, the greater the charging current and the faster the triac conducts following the start of each half cycle.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.