Abstract: An ultrasonic detector suitable for mounting in a position for surveying an area for a source of airborne ultrasound, which detector comprises a sensor for detecting an ultrasonic sound signal, characterised by a transducer configured to produce a broadband ultrasonic sound signal for reception by said sensor enabling said ultrasonic detector to perform a self-test.

Abstract: An ultrasonic detector suitable for mounting in a position for surveying an area for a source of airborne ultrasound, which detector comprises a sensor for detecting an ultrasonic sound signal, characterised by a transducer configured to produce a broadband ultrasonic sound signal for reception by said sensor enabling said ultrasonic detector to perform a self-test.

Abstract: An ultrasonic detector suitable for mounting in a position for surveying an area for a source of airborne ultrasound, which detector comprises a sensor for detecting an ultrasonic sound signal, characterized by a transducer configured to produce a broadband ultrasonic sound signal for reception by said sensor enabling said ultrasonic detector to perform a self-test.

Abstract: An ultrasonic detector suitable for mounting in a position for surveying an area for a source of airborne ultrasound, which detector comprises a sensor for detecting an ultrasonic sound signal, characterised by a transducer configured to produce a broadband ultrasonic sound signal for reception by said sensor enabling said ultrasonic detector to perform a self-test.

Abstract: An ultrasonic detector suitable for mounting in a position for surveying an area for a source of airborne ultrasound, which detector comprises a sensor for detecting an ultrasonic sound signal, characterised by a transducer configured to produce a broadband ultrasonic sound signal for reception by said sensor enabling said ultrasonic detector to perform a self-test.

Abstract: An ultrasonic detector suitable for mounting in a position for surveying an area for a source of airborne ultrasound, which detector comprises a sensor for detecting an ultrasonic sound signal, characterised by a transducer configured to produce a broadband ultrasonic sound signal for reception by said sensor enabling said ultrasonic detector to perform a self-test.

Abstract: An ultrasonic detector (10) suitable for mounting in a position for surveying an area for a source of airborne ultrasound, which detector comprises a sensor (20) for detecting an ultrasonic sound signal, characterized by a transducer (64) configured to produce a broadband ultrasonic sound signal for reception by said sensor (20) enabling said ultrasonic detector to perform a self-test.

Abstract: A detector (100), such as a gas or flame detector, having a housing which provides protection against explosion and/or ingress, which detector comprises at least one temperature sensor, a heating and/or cooling element (14) and at least one heat pipe (7, 8, 9) connected between a first and a second part of the detector, the arrangement being such that, in use, said temperature sensor provides an output signal indicating a temperature of a part of said at least one heat pipe (7, 8, 9), and which output signal is used to control said heating and/or cooling element (14) to warm or cool said at least one heat pipe, whereby the temperature at each of said first and second parts of the detector may be maintained substantially the same.

Abstract: An ultrasonic detector (10) suitable for mounting in a position for surveying an area for a source of airborne ultrasound, which detector comprises a sensor (20) for detecting an ultrasonic sound signal, characterised by a transducer (64) configured to produce a broadband ultrasonic sound signal for reception by said sensor (20) enabling said ultrasonic detector to perform a self-test.