Phase change warning devices
US4329682A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 7, 1978 |
| Grant date | May 11, 1982 |
| Priority date | — |
| Expiry date | Sep 7, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B19/02
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A method and apparatus is provided for detection of the onset of a physical change in state of a flowing fluid medium or component of a flowing fluid medium, e.g. freezing, boiling, sublimation, crystallization. A surface in contact with the fluid medium is maintained at a temperature that is an approximately fixed amount below or above the general stream temperature of the fluid, by means of a thermo-electric heat pump, the temperature difference being sensed by thermo-couple means to obtain a control signal for regulating the output of an amplifier that drives the heat pump. Upon occurrence of the physical change in state to be detected, the amplifier output will fall or rise rapidly as the system tries to regulate the power input to the pump to keep the temperature difference constant and this swing is detected by a signal generator monitoring the output of the amplifier.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.