Undercompression and overcompression free helical screw rotary compressor
US3936239A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 26, 1974 |
| Grant date | Feb 3, 1976 |
| Priority date | — |
| Expiry date | Jul 26, 1994 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF05B2250/25
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
An axially shiftable slide valve member in a rotary, helical screw compressor carries a port which senses the pressure of the working fluid in the trapped volume just before uncovering of the closed thread to the discharge port and compares that pressure with the line pressure at the discharge port and shifts the slide valve member to balance the pressures and prevent overcompression or undercompression of the compressor. The screw compressor may be provided with two identical but oppositely oriented slide valve members on opposite sides of the intermeshed helical screws with one slide valve member controlling the capacity of the compressor and the other balancing the closed thread pressure at discharge with discharge line pressure. Compressor rotation may be reversed to eliminate the need for a reversing valve where the compressor operates in heat pump or reverse flow defrost refrigeration applications, with the two slide valves trading functions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.