LIQUID METERING

摘要

A meter (2) to measure the volumetric flow rate of a liquid, for example water, is formed with a pipe (4) forming a liquid flow path containing a low power electrical heater (12). A temperature sensor (19) measures the temperature T1 of the liquid adjacent to an upstream end of the heater and a temperature sensor (20) measures the temperature T2 of the liquid adjacent to a downstream end of the heater. The heater (12) adds heat power of a value P to the liquid. A control arrangemen t (18) comprising computer means calculates the flow rate Q using the expression (a) where ST1 and DT1 are respectively the specific heat capacity of the liquid and the density of the liquid at the temperature T1 measured by the sensor (19).