The response of these sensors depends not only on the gas but also on ambient temperature which may range from below zero to over 100 degrees F. Temperature compensation is conventionally achieved with a pair of CC or TC sensors. One sensor in each pair compensates for temperature effects included in the response of the other to sampled gas. Since no two sensors respond identically to temperature changes, there is some thermal noise which masks the signal at low gas concentrations. Bascom-Turner has developed a new method of power switching a single sensor to compensate for temperature changes. Besides improving sensitivity and accuracy, this new method saves power since a single sensor consumes less than half the power consumed by a pair of sensors.
Power savings translate into less weight, longer operating time, and lower operating costs.
A leak locator must be fast enough to keep an operator from overshooting a leak by more than a few inches when scanning in a hurry. The required response time is approximately 0.50 sec. A conventional CGI with a speed of 10 sec. is far too slow for locating leaks. The speed at which the detector responds depends on the speed of the sensor and how fast the gas reaches the sensor. A power-switched, catalytic combustion sensor responds in 0.25 sec.