Means for producing an optimized cooler expander waveform
US4417448A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 20, 1982 |
| Grant date | Nov 29, 1983 |
| Priority date | — |
| Expiry date | Jan 20, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02K33/14
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A means for producing an optimized cooler expander waveform for a closed le cryogenic cooler. The cooler displacer is driven by magnetic and spring biasing means through four repeated phases of each cycle to produce four portions of the optimized cooler waveform in which each portion takes up about 25% of the total cycle. The portions are comprised of a constant velocity in opposite direction and dwell times with smoothed corner transitions between each portion. Control means for controlling the displacer movement to produce the specific waveform may be provided by a function generator applying the desired waveform into a displacer control drive circuit which has as a second input a sensory signal of the actual position of the displacer. The actual position and the desired position are continuously compared while the drive circuit drives two opposing solenoids during the constant velocity phases of the displacer movement with two spring biasing means holding the displacer during the dwell times at the end of each stroke.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.