An Ultrasonic Gas Leak Detector consists of five main sections:
· Corrosion resistant stainless steel microphone transducer.
· User definable ultrasonic high-pass filter circuit.
· AC to DC rectifier.
· User definable alarm delay circuit.
· User definable alarm level circuit.
· NAMUR compatible alarm relay output.
The special high quality stainless steel microphone picks up broad noise from the surroundings and feeds the
signals to a specially designed ultrasonic high-pass filter. The high-pass filter extracts the ultrasound from the broadband noise. A rectifier circuit converts the AC signal into a true RMS (Root Mean Square) DC value.
A level detection circuit detects if the ultrasonic level exceeds the alarm level. The level detection is user
definable. If the alarm level has been exceeded, the detection circuit will trigger an alarm delay timer, which
will prevent false alarms. The timer runs for a predefined period (the user-definable alarm delay). If the
ultrasonic level is still above the alarm level after the alarm delay time-out, the alarm relay of the detector is
activated.
The Ultrasonic Gas Leak Detector can be connected to the plant DCS system or to the existing fire and gas
detection system by means of EX approved safety barriers.