| 摘要 |
PCT No. PCT/GB90/00264 Sec. 371 Date Sep. 20, 1991 Sec. 102(e) Date Sep. 20, 1991 PCT Filed Feb. 16, 1990 PCT Pub. No. WO90/09567 PCT Pub. Date Aug. 23, 1990.A flow meter includes a body located in thermal contact with a fluid, the flow rate of which is to be measured, a heater in thermal contact with the body, a first temperature sensor for measuring the temperature of the body, and a second temperature sensor for measuring the temperature of the fluid. The flow meter also includes mechanisms for calculating the differential temperature between the fluid and the body, for supplying power to the heater, for measuring the rate at which power is supplied to the heater, for setting a predetermined target differential temperature, and predetermined maximum and minimum differential temperatures, and for comparing the calculated differential temperature with the predetermined target, maximum and minimum differential temperatures. The flow meter further includes mechanisms for controlling the rate that power is supplied to the heater and for calculating the flow rate from the measured rate of power supply and the difference between the temperatures of the body and the fluid. |
