AN APPLICATION OF A THERMOSENSITIVE QUARTZ RESONATOR FOR LIQUID FLOW-RATE MEASUREMENT

The temperature-frequency dependence of a thermosensitive quartz reson ator is used for the measurement of liquid flow rate. Because of a spe cial quartz cut the resonator has very high temperature sensitivity wh ich allows very small temperature changes to be detected. Using a heat er the resonator is heated to a temperature higher than the ambient te mperature. The resonator and the heater are designed together as a mea suring probe which is placed in the path of a flowing liquid. The liqu id flow cools the resonator and causes a frequency change. Using anoth er resonator the temperature difference between the temperatures of th e heated resonator and the ambient liquid is measured. In a number of experiments the relationship between the resonator temperature and wat er flow rate is investigated. A theoretical analysis for this relation ship is delivered too. It is found that when the water flow rate is va ried from 0. 1 to 1.4 m/s the resonator temperature changes within 15- degrees-C.