Compressor reverse rotation of variable duration on start-up
US8292599B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 13, 2007 |
| Grant date | Oct 23, 2012 |
| Priority date | — |
| Expiry date | Dec 24, 2027 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF04C29/045
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
In a method of operating a compressor at startup, the compressor is rotated in reverse for a brief period of time. The compressor is of a type that does not compress liquid when rotated in reverse. The purpose is to boil off the liquid refrigerant from the oil by heating and agitating the mixture of oil and refrigerant in the oil sump. This results in a much more benign forward start as less refrigerant is drawn into the compressor pump and the amount of oil pumped out of the compressor on start up is minimized. Also, the viscosity of oil is increased and lubrication of the bearings is improved. After a short period of time reverse rotation is stopped and the compressor can start rotating in the forward direction. The short period of time of reverse rotation is varied based upon system conditions. In one embodiment, the variation can occur by reducing the reverse run time as ambient temperature increases. In another embodiment, electrical conditions such as incoming voltage and/or a ratio of voltage to frequency can be utilized to change the reverse run time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.