Amphenol VQ41TSB

VQ41TSB is a flammable gas sensor optimized for detecting ammonia in air. It operates by detecting the heat generated from catalytic oxidation of ammonia on a pair of matched elements. The sensor can be used to detect ammonia in air at concentrations above 600 ppm, and is particularly suited for monitoring volume concentrations in the range of 0 to 1.5% (0 to 10% LEL). This makes the sensor ideal for ammonia refrigerant detection systems designed to comply with the BS4434:1989 standard.

Interference from water vapor or carbon dioxide is eliminated through the use of a matched inert compensator element. An improved poison-resistant construction prevents common substances from gradually degrading sensor performance, with particularly high protection against silicone poisons. In the latter case, the level of protection significantly exceeds that of standard poison-resistant catalytic flammable gas detectors. Testing has shown no effect on zero value or ammonia sensitivity after exposure to 100 ppm hexamethyldisilazane (HMDS) for over one hour.

The VQ41TSB incorporates novel catalyst chemistry and device construction to optimize response to ammonia. Under normal operating conditions, sensitivity to xylene is negligible and sensitivity to methane is low; however, the device can be used to detect hydrogen and butane.