Accession Number:

AD0291096

Title:

AN AUTOMATIC GUARD-RING TEMPERATURE CONTROLLER FOR THERMAL-CONDUCTIVITY MEASUREMENTS

Descriptive Note:

Technical Report

Corporate Author:

QUARTERMASTER RESEARCH AND ENGINEERING COMMAND NATICK MA NATICK United States

Report Date:

1962-10-01

Pagination or Media Count:

26.0

Abstract:

An automatic controller is described, which maintains the guard ring at the same temperature as the hot plate in an apparatus formeasuring thermal conductivity. Control is maintained in response to the signal from a 6-power thermopile, which actuates a commercialelectronic null detector. The output of the null detector drives a commercial magnetic amplifier. Proportional control is obtained bysuperposing an oscillating signal, generated by a Wien-bridge oscillator, on the control signal, so that the control relay continuallyopens and closes with a period of about 5 seconds. An increase in the demand for power causes the closed intervals to become longerand the open intervals to become shorter. Opening or closing of the relay changes the power input by only about 2 percent whenconditions suitable for making measurements exist. Temperature control to within 2 mdeg C can be achieved under favorable conditions.

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE