GB729180A - Apparatus for indicating or measuring the flow of liquid through a conduit - Google Patents

Abstract

729,180. Measuring fluid How electrically. NAAMLOOZE VENNOOTSCHAP DE BATAAFSCHE PETROLEUM MAATSCHAPPIJ. March 3, 1953 [March 5, 1952], No. 5852/53. Class 40(1). The invention relates to means for determinging the flow of liquid through a pipe 1 by measuring the amount of heat supplied electrically to a probe 6 disposed in the flow to keep a constant temperature different t between this probe and that of the liquid which is measured by an unheated probe 7, upstream of probe 6. The relationship between heating energy W supplied per unit time and liquid flow Q per unit time is shown in Fig. 2. The linear portion of the curve intersects the W axis at W 1 and, according to the invention, in order to get direct proportionality between the flow Q and the metered energy the portion W 1 of the heating energy W is not metered. The energy W 1 is supplied over a resistor 14 from the mains M independently of the watt-hour meter 9, which measures W-W 1 <SP>1</SP>, where W 1 <SP>1</SP> is the average value to which W 1 <SP>1</SP> falls when additional heating current is intermittently fed through a microswitch 13 automatically controlled by the temperature difference t. As shown, the microswitch is controlled by the fluid pressure difference in bellows 10, 11 responsive, respectively, to the probe temperatures, but thermocouples or temperature sensitive resistors may be used to regulate the flow of measured heat. The Specification explains that where the liquid flow does not fill the pipe 1, cylindrical or prismatic probes preferably extending vertically downwards for 0.8-0.9 of the pipe diameter are preferably used, in which case the meter readings are independent of the height of liquid in the pipe.