Heat pulse time difference type flow detection method

Abstract

This invention discloses a heat impulse time lag flow measurement method, which puts sensor in the parallel pipe to the flow direction to get heating temperature measurement, or its denote output signal curve; then it measures the temperature change on downstream of temperature measurement element along flow direction to get output signal curve of temperature element; it compares two curves to measure the time lag value to get flow speed. This invention especially applied in the measurement of middle and low speed range of gas with constant components.

Description

technical field [0001] The invention relates to a mass flow detection method, in particular to a thermal pulse time difference flow detection method. Background technique [0002] Existing thermal flowmeters are divided into two types, 1. Anemometer; 2. Thermal flow sensor. [0003] Anemometers work based on the Golden Law introduced in 1914 to detect flow velocity by detecting the degree of heat dissipation from the heater itself when exposed to the fluid. The sensor of this mode includes a straight channel with fixed geometric dimensions, a heater made of temperature-sensitive material, a reference temperature sensor for measuring the original temperature of the fluid and the corresponding control and measurement circuit. How much heat is used to measure the flow rate. The sensor element can be made of various temperature-sensitive materials. This sensor has a high response frequency and a large speed measurement range, but it cannot be used for long-term measurement, c...

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Problems solved by technology

Although the linearity of the upstream and downstream temperature difference curve thus obtained is affected in the low-speed section, the saturation point of the curve has to be moved later, thereby increasing the measurement range

[0005] The common problem of the above two measurement methods is that if they are used in occasions that require real-time monitoring of the flow rate, both measurement methods need to supply power to the heating element for a long time to keep it in a heating state, so the energy consumption and the sensor itself Loss is bigger

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