Temperature controlling means for a thermostat for use in measuring viscosity
US4993480A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 17, 1989 |
| Grant date | Feb 19, 1991 |
| Priority date | — |
| Expiry date | Nov 17, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05D23/1931
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Temperature controlling means for a thermostat for use in viscosity measurement including: a first thermometer detecting the temperature of a fluid sample which is immersed in a thermostat and whose viscosity is measured; a first controller obtaining the difference between a desired set point and the detected value of the sample temperature, momently calculating a set point of temperature of the thermostat according to an operation formula expresed as a function of the above temperature difference and making a controlled signal corresponding to the calculated set point; a second thermometer detecting the temperature of the thermostat; a heating and cooling device for heating and cooling a medium bath of the thermostat; and a second controller making a controlled signal for operating the heating and cooling device under a PID control formed on the basis of the difference between the calculated set point and the detected value of the thermostat temperature and inputting the PID controlled signal into the heating and cooling device.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.