Accession Number:

AD0260385

Title:

A PORTABLE THERMISTOR-BRIDGE GAS LEAK DETECTOR

Descriptive Note:

Corporate Author:

NAVAL RESEARCH LAB WASHINGTON D C

Personal Author(s):

Report Date:

1961-07-01

Pagination or Media Count:

18.0

Abstract:

A new portable gas leak detector useful for locating leaks in pressurized systems containing any gas having a thermal conductivity different from that of air is described. The detector is accoupled and hence does not respond to the gas concentration in the ambient air but only to the change in concentration encountered in the vicinity of a leak. Investigations and experiments led to a choice of a thermistor bridge in which optimum response time and minimum sensitivity to gas flow rate variations is obtained by using thermistors shielded from the turbulence of the direct gas flow by glass envelopes but with a hole in each envelope to admit the gas by diffusion. Care was taken in the circuit design to prevent blocking of the high-gain amplifier by noise. Sensitivity of the gas leak detector was checked against a calibrated leak of Freon-12, and the device proved to be useful in locating Freon F-12 leaks of as small as 2 ounces per year. It was used with marked success during submarine operation. Author

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE