SU966539A1 - Device for sampling atmospheric air from aircraft - Google Patents

Description

(54) DEVICE FOR THE SELECTION OF SAMPLES OF ATMOSPHERIC AIR FROM AIRPLANE

The invention relates to devices for obtaining and preparing samples for investigation in a gaseous state and can be used in taking air samples on board an aircraft with the subsequent feeding of the samples taken to the gas analyzer.

A known aircraft intake device for supplying air to the cabin of the aircraft contains an air intake path for taking air from the atmosphere, a compressor, a pressure regulator that maintains constant pressure in the cabin of the aircraft, a thermostatic device for heating or cooling compressed air, and air circuits supplying air. in salon t

A disadvantage of the known device is the low quality of the sample, since the composition of the air passing through such an intake device during compression does not require a number of changes. So, for example, gas trace impurities enter into chemical reactions with compressor elements, interact with each other during the passage of air through long air lines, and catalytically

destroyed on the metal walls of the compressor and pipes.

It is also known a device for analyzing gases, comprising a detector, a supply line of the analyzed gas with installed flow booster, a pressure regulator and pneumatic resistances, an auxiliary gas supply line with installed respectively 10 pressure regulators and thermostated pneumatic resistance, measuring and correcting amplifiers and compensator , made in the form of a sensor pressure differential15. laziness 21.

A disadvantage of this device is the design complexity.

The closest in technical essence to the invention is a device for sampling atmospheric air from an aircraft, containing a flow meter, a thermostatically controlled input line and a sensing element of a gas analyzer 3.

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Claims (3)

A disadvantage of the known device is the low accuracy of air analysis caused by the fact that a change in air pressure with a change in the altitude of the aircraft causes a change in the mass flow rate of the simulated air entering the gas analyzer, which significantly impairs the condition of the gas analyzer. The purpose of the invention is to improve the quality and accuracy of the analysis by reducing the water content by stabilizing the pressure of the air sample. This goal is achieved by the fact that the device is equipped with a thermostatically controlled pneumatic resistance, installed at the inlet of the sensing element, and a pressure regulator, the inlet of which is connected to the outlet of the sensing element, and the output is with the flow meter. In addition, the pneumatic resistance is made in the form of a capillary, the dimensions of which are determined by the following dependence TG p p max min min g - capillary radius, mm; mph is the minimum possible dynamic viscosity coefficient of the air being analyzed; maximum possible atmospheric pressure; the minimum possible pressure at the maximum height of the sampling; 2 - capillary dyne, cm; Q - performance is prompted. At the maximum height of the plane, the capillary dimensions are determined by the following relationship, 4p g 4 4.8-10 ie -Q where r is the capillary radius, mm; E is the length of the capillary (1-100) cm; Q - performance induce l (0.1-10-5-0.1). . The drawing shows a device for sampling atmospheric air from an aircraft. The device consists of an input mains (1), 1 (1) electrical resistance (2), a sensing element of a gas analyzer (3), a thermostat (4), a pressure regulator (5) and a flow indicator 6. In addition, the device is equipped with a flow indicator (7) and temperature and pressure indicators (8). in order to facilitate its operation, it is connected with the help of the output line 9 with the external atmosphere; the device works as follows. The incoming flow of the analyzed air flows through the inlet line 1 and pneumatic resistance 2 into the sensing element of the gas analyzer 3. From there, the air is sucked out through the pressure regulator 5 by the booster b and is discharged to the outside through the line 9. The air flow is monitored using the flow indicator 7. Maintaining constant: the air temperature is carried out by a thermistat 4, which encloses the inlet line, pneumatic resistance 2, a sensitive element of the gas analyzer 3. Maintaining a constant pressure analysis Rui air in the sensor element 3 is provided pnevmosoprotivleniem 2 and a pressure regulator 5. The temperature and analyzed air pressure is controlled by temperature indicators and Pressure €; audio 8. pnevmosoprotivleni 2 parameters are selected from those reasons that the number of incoming atmosfe-; air through the air resistance 2 to the sensitive element 3 should be at all flight altitudes of the aircraft less than the amount of air that can be taken from the sensor element 3. Pnevosopr po5 Aired9 Equal flow of air entering the sensitive element 3 and taken from there is achieved by the operation of pressure regulator 5. Pressure regulator 5 must be set to the minimum possible atmospheric pressure, which is at the highest possible height of the aircraft, i.e. . for an IL-18 aircraft with a flow of 10 km, the pressure maintained in the sensing element should be about 250 mbar (pressure at an altitude of 10 km). Ensuring the minimum length of the inlet line, its performance, and pneumatic resistances from a chemically inert material, such as Teflon or silica, minimizes the distortion of the composition of the analyzed air. The application of the Invention allows to improve the measurement accuracy by stabilizing the error. Claim 1. Device for sampling atmospheric air from an aircraft, containing a flow rate booster, a temperature-controlled input line and a gas analyzer sensitive element, differently to improve the quality and accuracy of the analysis by reducing the error by stabilizing the pressure of the air sample, it equipped with a thermostatically controlled pneumatic resistance installed at the input of the sensing element and a pressure regulator, the inlet of which is associated with the outlet of the sensing element, and the outlet is connected to a flow booster. 2. The device according to claim 1, that is, so that the pneumatic resistance is made in the form of a capillary, the dimensions of which are determined by the following relationship. i HH - „„ p; .Q, P | lin) where -, LMMH is the minimum possible coefficient of dynamic viscosity of the analysis of the air being used, max m xymshnr possible pressure in the atmosphere; RMII - the minimum possible pressure at the maximum sampling height of samples; g - radius of the capillary, mm; C is the length of the capillary, cm; Q - performance is prompted. 3. The device according to claim 2, which is based on the fact that at the maximum flight altitude of the aircraft, the dimensions of the capillary are determined by the following dependencies g 4.8-10 where G is the radius of the capillary / mm ; E is the length of the capillary (1-100) cm; Q - performance booster (0.1. -0.1). Sources of information taken into account in the examination 1. Passenger aircraft IL-18. Technical description. Prince Vi. M., Oborongiz, 1961, p. 64-93. 2. USSR author's certificate on application 2895422 / 23-26, cl. G 01 N ZL / 08, 1980. 3. Fedynsky AV, YUSHKOV VA, Shifrin D.} 1, Sholokhova N.G. The use of the coulometric method for measuring the humidity of the atmosphere from a plane, - Meteorologists and Hydro, 1978, 6, p. 105-109.