Ultrasonic apparatus for measuring the position of a liquid level

TLDR: In this paper, an ultrasonic liquid level measurement is conducted through a guide for a tube filled with an auxiliary liquid with acoustic properties similar to those of the liquid whose level is to be measured.

Abstract: 1,123,939. Ultrasonic measurement of liquid level. COMMISSARIAT A L'ENERGIE ATOMIQUE. 13 Dec., 1966 [15 Dec., 1965], No. 55822/66. Heading H4D. In an ultrasonic liquidlevel gauge, ultrasonic waves are conducted through a guide vowprising a tube filledhithan auxiliary liquid moaing acoustic properties similar to those of the liquid whose level is to be gauged. For measuring the level 17 of liquid sodium or sodium - po - tassium coolant 51 in a nuclear reactor vessel the tube 1, containing a eutectic sodiumpotassium mixture, is adjustably mounted in the vessel wall by means of flanges 15, 16, screws 19 and metal bellows 18. The tube 1 is sealed by acoustically transparent end-plates 3, 4, and is surrounded by perforated tube 28 which dampens movements of the coolant surface 17 and also supports a conical reflector 22. Ultrasonic pulses generated by a quartz transducer 6 (adjustably mounted in a kerosene-filled casing 5) pass through the waveguide, are reflected from reflector 22, and pass between tubes 1 and 28 to the coolant surface 17 from which they are reflected back via the same path to the or a further transducer. The echo-time of a pulse provides a measure of the coolant level. Lugs 31 at known positions in tube 28 provide reference echoes for calibration purposes. In alternative embodiments the gauge is mounted in or near the bottom of the reactor vessel (Figs. 3 and 4, not shown), whereby the ultrasonic pulses can be directed through the waveguide to the coolant surface without the need for the conical reflector 22, or is mounted in the vessel side wall (Fig. 5, not shown) with the waveguide horizontal, a plane reflector being used to direct the pulses upwards to the coolant surface.