| 摘要 |
1,071,734. Controlling reactors. N. MAROPIS. May 21, 1964 [May 21, 1963], No. 21091/64. Heading G6C. [Also in Division H4] An indication of whether the tip of a probe is located in a liquid, foam, or vapour phase, and an indication of the liquid content of the foam phase, is provided by an arrangement in which comparative measurements of the ultrasonic power transmitted along the probe into the fluid are obtained by a standing-wave ratio technique. The probe comprises a disc or rectangular plate tip 35 connected through a coupler 38, 40 to a magnetostrictive or piezoelectric transmitting transducer 41, and is carried in a tubular housing 32 by means of an anti-vibration mounting 37, 39 (detailed in Fig. 1A, not shown). The plate 35 is dimensioned to vibrate in a flexural mode at the operating frequency of transducer 41. Vibration sensing elements 78, 80 are located on the probe 'at a node and adjacent antinode of the standing- wave set up in the probe, and are coupled through an amplifier to a read-out device 83, such as a watt-meter, which provides an indication of the standing-wave ratio and hence the acoustic impedance match between the probe tip and the medium in which it is vibrating. Provision for cooling the transducer 41, and the sensing elements 78 and 80 if they are made from barium titanate, is desirable. The invention may be used for liquid-level control, e.g. in a boiling water nuclear reactor, in chemical manufacturing, or in beer brewing, provision being made for racking the probe housing 32 up or down through a bushing 30 in the wall 10 of a fluid-containing vessel. |
