Improvements in or relating to The Detection of Leaks in Bottles for Liquefied or Compressed Gas

摘要

1,152,404. Ultrasonic inspection devices. COMPAGNIE GENERALE D'AUTOMATISME. 30 Jan., 1967 [30 Nov., 1966], No. 4393/67. Heading H4D. In a system for detecting leaks from bottles 3 of liquefied or compressed gas the bottles are passed through a tank of liquid 2, any bubbles formed in the liquid intercept a beam of ultrasonic energy propagating between transmitter 21 and receiver 22 and an alarm is actuated if, during passage of a bottle, the received signal strength drops below a threshold value more than a pre-selected number of times or for longer than a pre-selected time. As shown, water is supplied to tank 1 via conduits 25 and hood 5 and a head h 1 is maintained by vacuum pump 9 and constant-head device 10. Unit 27 provides an output pulse each time the received signal strength is below the threshold, i.e. for each bubble, and the pulses are counted at 28. Alarm 31 is actuated when a preset count is reached. For large leakages the bubbles tend to overrun one another and result in the received signal remaining below threshold for an appreciable time. Unit 32 then actuates the alarm 31 after a preset time. For greater leakages hood 5 becomes filled with gas and the received signal strength remains below threshold for an even greater time. This condition is sensed by unit 36 and causes passage of the bottles to stop until head h 1 is restored. Provision is made for counting faulty and non- faulty bottles separately on registers 41, 42 and for ejecting faulty bottles from a conveyer.