| 摘要 |
PURPOSE:To protect an electromagnetic pump always correctly without affection of the influence of the operating state of a system by providing a temperature detector for detecting the temperature of fluid, introducing the output to a function generator, adding by an adder the flow rate signal from the generator and an actually measured flow rate signal and comparing the outputs. CONSTITUTION:A temperature detector 14 which detects the temperature of conductive fluid flowing in a pipe 6 is provided, the output of the detector 14 is led to a function generator 15, the output of the generator 15 is inputted to an adder 16, the output of an electromagnetic flowmeter 7 is inputted through a flow rate converter 8 to the adder 16, and the output of the adder 16 is applied to a comparator 9. The generator 15 outputs a flow rate obtained by a temperature characteristic curve which varies in accordance with the prescribed relation. In this manner, the out of the comparator 9 which is not affected by the influence of the variation in the temperature of the fluid due to the alteration of the operation of the system can be obtained, thereby always correctly protecting an electromagnetic pump. |
