System and method for heater control for evaporation of cryogenic fluids for cooling scientific instruments
US5973299A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 11, 1997 |
| Grant date | Oct 26, 1999 |
| Priority date | — |
| Expiry date | Sep 11, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05D23/1919
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A heater controller for allocating heaters to cool a thermal chamber of a scientific instrument evaporates cryogenic liquid to produce a coolant gas. The gas is injected into a chamber to cool a sample disposal therein. The controller allocates low-capacity heaters in compliance with IEC guidelines to prevent problems generally associated with switching of large current loads, such as heaters. In one embodiment, heaters are activated so as to avoid jump discontinuities by effectively averaging the power delivered by the heaters. A second embodiment reduces complexity by essentially disregarding the problem of the jump discontinuity. A third embodiment groups the heaters according to a binary grouping scheme. The heater controller of the present invention can be used to control temperature according to a user supplied temperature profile.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.