ULTRASONIC THICKNESS METER

摘要

An ultrasonic thickness meter (10) which is used for measuring the thickness of pipelines used in the oil/gas industry, the thickness of the pipelines generally being in the range 5mm to 100mm. The meter (10) uses an intrinsically safe low voltage LCD (28) under control of a low voltage microprocessor (126). Power is supplied for up to 4 hours from a 4.5 volts battery supply and low internal capacitance is provided without the need for barrier and enclosure protection. An ultrasonic transmitter (22) and receiver (26) are contained in a twin crystal probe (14) and reflected ultrasonic signals are sampled by an A/D converter (56) and stored in a digital memory (50) which is periodically read out under the control of the microprocessor (126) to the low voltage dot-matrix LCD (28). The LCD (28) provides a clear visual indication of thickness (25) on a scale and gives a digital read-out at the point at which the thickness is measured. The meter (10) including a calibration block (34) for performing an internal calibration before and after measurement.