Intelligent constant-flow individual air dust sampler and constant-flow control method

Abstract

The invention discloses an intelligent constant-flow individual air dust sampler and a constant-flow control method. The sampler is provided with a buffering air capacitor (2), an air capacitor (4), a flow closed-loop control circuit (16), pressure measuring openings (5, 6 and 7) and a differential pressure sensor (6), wherein the test end of the differential pressure sensor (6) is communicated with the pressure measuring opening on an air chamber (5) through a hose; the signal output end of the differential pressure sensor (6) is connected with an input port of a singlechip (7) through an amplifier and an A / D converter; and the output control end of the singlechip is connected with the electrical signal control end of the driving motor of an air pump (3) through an air pump control unit (19). The constant-flow control method comprises: a, establishing a flow correction curve; b, testing the backpressure of working gas at the outlet of the air chamber (5); and c, comparing a measured current backpressure with the flow curve and controlling the air pump (3) to implement constant-flow output. The sampler and the method can realize flow closed-loop control and automatic constant-flow sampling, improve the accuracy of dust mass concentration measurement and ensure reliable use and accurate control.

Description

technical field [0001] The invention relates to a monitoring instrument for labor protection, sanitation and epidemic prevention, in particular to an intelligent constant-flow individual air dust sampler for monitoring the concentration of various harmful gases and dust. Background technique [0002] Dust samplers are widely used in labor protection, health and epidemic prevention departments, and are used to monitor various harmful gases and dust concentrations. In environmental protection, metallurgy, building materials, chemical industry, occupational disease prevention and other industries, dust samplers are usually used to evaluate the environment of dusty workplaces, to measure the impact of dust in a working class on human health, and to study the prevention and control of occupational diseases. , production environment, equipment transformation to provide a theoretical basis. The method of dust sampler to measure the mass concentration of dust in the air is the grav...

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Problems solved by technology

The other is to use a rotameter for measurement. The rotameter cannot provide electrical signal output, cannot realize feedback control, automatic compensation and correction, and cannot constitute a closed-loop control system.

If a conventional orifice flowmeter is used, in the low flow range of the instrument, there are deficiencies such as low accuracy, low resolution, and large air path resistance. Mass flow sensors also have the disadvantages of large air path resistance and high cost.

Existing individual samplers, due to the pulsation of the air pump, produce airflow spikes. When comparing the flow with other flowmeters, due to the fluctuation of the airflow, it is not easy to compare the readings

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