Method and apparatus for measuring single-sensor heat type gas flow

Abstract

The invention discloses a hot type gas flow measuring method of a single sensor and a device thereof. The device comprises a sensor, an amplifier, a low pass filter, a singlechip microcomputer and a voltage-controlled supply circuit, wherein, the sensor is composed of a divider circuit formed by connecting a resistance and a platinum resistance PT20. The invention has simple structure, the single platinum resistance PT20 is taken as the measuring element, and the gas flow is calculated by controlling the platinum resistance PT20 to work under the two different setting temperatures and measuring the output voltage of the platinum resistance under the two different setting temperatures. The measuring method and the device of the invention are adopted to measure the gas flow, which does not need to complement the resistance additionally, eliminates the influence of the gas temperature on the flow measurement, improves the measuring precision and reduces the production cost. Tests indicate that the measuring precision of the gas flow can reach 1% and the flow measuring range ratio is approximately 100:1 by adopting the method and the device of the invention.

Description

technical field [0001] The invention relates to a single-sensor thermal gas flow measurement method and a device thereof. Background technique [0002] The thermal gas flowmeter is a new type of gas flow detection instrument developed on the basis of the early hot wire anemometer. It has the advantages of low pressure loss, large flow range, high precision, no moving parts and low flow measurement. It has been widely used Used in aviation, aerospace, energy, medicine, automobile industry and natural gas pipeline transportation and other industries. Its basic principle is based on the convective heat transfer of the heated sensing element. When gas flows over the surface of the heating element, it will take away part of the heat, causing a change in the resistance value, which is related to the flow rate and temperature of the gas. At present, thermal gas flowmeters are divided into constant flow type and constant temperature type according to the circuit working mode of th...

AI Technical Summary

Problems solved by technology

Due to the nonlinearity of the temperature compensation resistor and the difference between the resistors, the circuit debugging process is more complicated, which affects the measurement accuracy to a certain extent.

Although a temperature compensation method based on a single sensor has been proposed abroad, the measurement process needs to switch the resistance of the bridge arm, the circuit is relatively complicated, and the bias voltage of the operational amplifier has a certain impact on the measurement results, resulting in large measurement errors

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