SU974197A1 - Device for sampling air - Google Patents

Description

(54) AIR AIR DEVICE

one

The invention relates to instrumentation, and more specifically to automatic air sampling devices, and can be used in monitoring the pollution of the air basin of cities, industrial centers, as well as in the current sanitary inspection of the air condition in the shops and premises of industrial enterprises.

A device for sampling air containing an absorbing device is known. 10 the flow driver and the flow meter equipped with a diaphragm installed at the inlet of the flow meter so that the air passes successively through the flow booster, the flow meter, the diaphragm and the absorption device 1.15

The disadvantage of the device is the low accuracy of the analysis.

The closest to the technical essence of the invention is a device for automatic sampling of atmospheric air, 20 containing an absorption device, a flow booster and a diaphragm, the output of which is connected to a flow booster. The air flow in this device is kept constant

by creating a flow rate by the critical flow mode through the diaphragm. The change in air flow is made by installing diaphragms with different critical sections (interchangeable nozzles) into the gas main 2.

Claims (2)

The disadvantage of this device is the dependence of the air flow through the diaphragm on the pressure at its inlet, which leads to an increase in the error of determining the concentrations of contaminants in chemical analysis of the absorber. The air pressure at the inlet of the diaphragm during operation of the device varies widely: depending on the atmospheric pressure, it changes to 10% of the nominal value. The value of air pressure at the inlet of the diaphragm is also influenced by the hydraulic resistance of the absorption devices, which, depending on the type and individual characteristics of the devices, varies within 1 to 10 kPa. Thus, fluctuations in the air flow rate through the diaphragm, depending on the atmospheric pressure and the characteristics of the absorption device, 3,974,197 devices make up 15–20% of the nominal value. In a laboratory analysis of an absorber, an error in determining the volume of air that has been passed through the absorber leads to an error in the determination of the concentration of air for the s sg. The aim of the invention is to determine the accuracy of determining the concentration of contaminants in the air. This goal is achieved by the fact that the device for air sampling, which contains an absorption device, a flow stimulator and a diaphragm, the output of which is connected to a flow stimulator, is supplied with a variable pneumatic resistance, the main and control inputs are pneumatic resistance, and the genes with the output of the absorption device output with aperture input. In such a device, the change in atmospheric pressure (or the hydraulic resistance of the 20 absorber devices) is compensated by the pressure drop at the variable pneumatic resistance, and with increasing atmospheric pressure, the pressure drop at the variable pneumatic resistance also increases. With the use of adjustable pneumatic resistance, the deviations of the pressure at the inlet to the diaphragm are reduced to a magnitude of 5%, from the value to be stabilized, when the absolute pressure deviates from the inlet of the pneumatic resistivity from the nominal value by 20%. Air flow through the diaphragm is stabilized with the same nausea. The magnitude of the pneumatic resistance depends on the pressure of the air entering its control input. The drawing shows a diagram of the proposed device. The device contains an absorption device 1, a variable pneumatic resistance 2 with a main input 3, a control input 4 and an output 5, a diaphragm 6, a flow booster 7 connected to a pneumatic circuit. The device works as follows. When the flow rate drive 7 is switched on, the sample of the analyzed air is pumped successively through the absorber device H, sediment and filters (not shown), through alternating pneumatic resistance 2 connected by main input 3 to the output of the absorption device 1 and the diaphragm 6. The expense booster 7 creates a diaphragm outlet 6 times-50 cutting, necessary for the critical mode of expiring air through the diaphragm 6. From the output of the absorption device 1, air also flows to the control input 4 of the pneumatic counter-w-2. pressure to the control input 4 -55 shschem pressure drop (pnevmosoprotivlenie 2) between trunk input .3 and 4, the outlet 5 is increased, the characteristic tics pnevmosoprotivleni 2 are selected tag Kim that the pressure at the outlet 5 pnevmosoprotivleni 2 remains constant. Accuracy of pressure maintenance at the pneumatic resistance by-pass is determined in this case only by the accuracy of the pneumatic resistance set to E. 2. Thus, a change in the pneumatic resistance 2 compensates for the change in air pressure at the outlet of the absorption device 1 and the air flow through the diaphragm 6 remains constant. The error in the stabilization of the flow rate is fully determined by the characteristics of the variable temperature control 2 and is equal to 5% of the nominal value. The proposed device improves the accuracy of determining the concentrations of contaminants by 3-4 times. the actual operating conditions, the atmospheric pressure can vary from 80 to 120 kPa, and the hydraulic resistance of the absorption devices varies from 1 to 10 kPa, which totals 15-20% ° nominal (100 kPa), respectively, the flow rate changes and the error in determining the concentrations of contaminants for similar devices. In the proposed device, the error in determining the concentration of contaminants is removed up to 5%. The implementation of the invention has a significant sociocultural effect, which is manifested in the creation of improved equipment for combating environmental pollution. Claims An air sampling device comprising an absorber, a flow booster and a diaphragm whose outlet is connected to a flow booster is different in that it is equipped with variable pneumatic resistance, main and the control inputs of which are connected to the output of the absorption device, and the output to the input of the diaphragm. Sources of information taken into account during the examination 1. USSR author's certificate No. 634157, cl. G 01 N 1/22, 1976. 2. Bresler, PI and others. Automatic MTGoganal device for air sampling. - Hygiene and Sanitation, 1979, No. 5, p. 61. vo 40 -P J: