RU2230307C1 - Method of monitoring of aerosol contamination of gases fed for thermostatt ing of carrier rockets and spacecrafts - Google Patents

Abstract

FIELD: sampling technology, test of content of mechanical impurities in air and gas atmosphere utilized in space, gas, chemical, atomic and other industries. SUBSTANCE: in compliance with method gas is sampled from main line when linear velocities of flow in section of gas sampling in main line and across inlet of sonde are equal. Gas is supplied through sonde and sampling tube to sampling branch pipe. Gas is sampled for analyzer and into bypass line across inlet to branch pipe while linear velocities of flow are equal. Velocity and pressure of gas are simultaneously reduced to their specified values across inlet to sampling branch pipe and analyzer. Gas for analyzer and thermostatting is fed into analyzer through sonde and sampling tube over same channel. Thermostatting of analyzer is carried out from bypass line by its blowing. Then thermostatting and analyzed gases are released to atmosphere. System for realization of method includes sonde, sampling tube, shut-off member, conical chamber where sampling branch pipe is mounted coaxially for axial movement, analyzer and bypass line. System is provided thermal container housing analyzer, upper horizontal wall of thermal container has hole and conical chamber conjugate to it with major base is installed. One side wall has technological inspection port with cover fitting snuggly to body of thermal container. Gas releasing holes equipped with protective perforated enclosures are made in all other walls. EFFECT: provision for taking representative samples, accuracy and operational reliability of system. 2 cl, 3 dwg

Description

The invention relates to techniques for sampling and monitoring the content of mechanical impurities in air and gas environments and can be used for continuous monitoring - monitoring the purity of gases used in rocket and space technology, transported through main pipelines for temperature control of the rocket and spacecraft compartments at the starting position as well as in the gas, nuclear, chemical and other industries.

Such control of the purity of gaseous media in space rocket technology is envisaged in order to ensure reliable and trouble-free operation of onboard equipment of launch vehicles and spacecraft, in particular optical and sensitive elements of devices, solar panels and electronic units operating in open space.

The requirements for industrial purity of gases, gaseous media and air in terms of content and control in them, in disperse composition and mass concentration of mechanical particles are established by the standards GOST R 50555-93 “Classes of gas purity”, GOST R 50766-95 “Clean rooms. Classification. Certification Methods. ” US Federal Standard “Grades of Cleanliness for Air-Suspended Particles in Cleanrooms and Cleanrooms” FED-STD-209E, 1992, etc.

However, the absence in the technical documentation of recommendations on the use of tools and systems for monitoring gas purity with the required technical and operational characteristics for wide industrial use confirms the particular relevance of this area of development.

A known method of gas selection, which consists in the removal of gas from the main pipeline through a probe and a sampling tube to the analysis device, which is used, for example, an analytical filter, a precipitation column, a photoelectric meter (USSR author's certificate No. 180411, class G 01 N 1 / 22, 1963).

However, since the efficiency of the analysis devices is ensured only at low speeds of the analyzed gas, this method and the corresponding devices do not ensure the equality of the flow velocities of the dispersed medium in the sampling tube and in the main stream and, therefore, the conditions for isokinetic sampling are not ensured. In addition, at low speeds of the analyzed gas, impurities are deposited in the sampling tube. All this significantly affects the representativeness of the sampling and reduces the accuracy of the analysis in this way.

There is also a known method of gas sampling, including supplying gas from the main pipeline through a probe and a sampling pipe to the analyzer and to the bypass line, and during the sampling process, the gas flow rate is controlled so that the linear velocities in the sampling pipe and in the main pipeline are equal to each other (GOST 3022-70).

Using this method, it is possible to achieve a higher accuracy of gas analysis compared to other known methods.

The method is carried out by a device including a probe, a selective tube, control valves and an analyzer.

The disadvantage of this method and its corresponding device is the inability to obtain an isokinetic mode of motion of the dispersed medium in the analysis and bypass lines. In case of isokinetic violation, the concentration of the selected particles will not be equal to the concentration of the dispersed medium in the stream, therefore, the analyzed gas sample will not be representative. In non-isokinetic sampling, the following cases occur: the linear gas velocity at the inlet of the analyzer is less than the linear gas velocity in the sampling tube, the linear gas velocity at the inlet of the analyzer is greater than the linear gas velocity in the sampling tube. In the first case, the dispersed medium settles in front of the entrance of the analysis device and as a result there is an underestimation of the concentration of particles in the sample. In the second case, there is an overestimation of the concentration of particles with respect to the concentration of particles in the gas stream.

A known method of sampling gases and a device for its implementation according to the USSR patent No. 819613, class. G 01 N 1/22, 1978, in which increasing the representativeness of the sample is achieved by the fact that the gas is supplied to the bypass line and to the inlet of the analyzer at an equal linear speed. The device includes a probe, a selective tube, regulating valves. The outlet sampling tube is equipped with a conical chamber with a coaxial mounted in it with the possibility of movement by a sampling pipe connected to the analyzer.

To ensure isokinetic conditions for sampling, the linear gas velocity at the inlet of the analyzer is equal to the linear velocity of the gas discharged to the bypass line, at which there will be no curvature of the flow lines.

Taking into account a given constant gas flow through the analyzer and the linear gas velocity in the sampling tube that varies over a wide range depending on the linear gas velocity in the main pipeline, velocity equalization is achieved by changing the cross section of the outlet section of the sampling tube.

The gas sampling system for analysis by this method is shown in the book: Baibakov F.B., Sharapov V.M. Control of impurities in compressed gases. - M .: Chemistry, 1989 .-- 160 p., Pp. 27-29, 141, 142.

The gas sampling method and the device for its implementation according to patent No. 819613 make it possible to take reliable gas samples from process pipelines under pressure, and thereby significantly increase the accuracy of gas purity control.

The disadvantages of this method and its corresponding device are unproductive gas flow through the bypass line, which is many times higher than the gas consumption for analysis.

In addition, since the analyzer is located directly near the sampling device, which in turn is located in the area of the process pipeline, the analyzer is exposed to the environment (temperature, humidity, precipitation, wind loads), which negatively affects the measurement accuracy.

A device for sampling high pressure gases according to the patent of the Russian Federation No. 2152017, class G 01 N 1/22, 1998, containing a probe, a sampling tube, control valves, a conical chamber and a sample analyzer, while the conical chamber is made open at the base (the operating principle and design of the device are based on the gas sampling method and device for its implementation of the patent No. 819613).

The device according to patent No. 2152017 provides when operating as part of a high temperature air-conditioning system of launch vehicles and spacecraft at the starting position the required performance.

The disadvantages of this device also include unproductive gas flow through the bypass line and the environmental impact on the analyzer when using the device in the field, which reduces its technical and operational characteristics - efficiency, representative sampling, accuracy, reliability.

In addition, a known method and device for sampling gases according to the patent of the Russian Federation No. 2158421, class. G 01 N 1/22, 1999, containing a probe, a sampling tube, a conical chamber with an open base, a sampling pipe and a sample analyzer (the operating principle and design of the device are also based on the sampling method and device for its implementation according to patent No. 819613) . The method and device for sampling gases according to patent No. 2158421 are implemented to monitor the purity of thermostatic low-pressure air, are closest to the present invention in terms of technical nature and the achieved result, and are selected as a prototype.

The disadvantages of this method and device also relates to unproductive gas flow through the bypass line. In addition, in the event of strong wind flows in the atmosphere, it is possible to pressurize the open part of the conical chamber and disrupt the stationary flow of the gas medium, which leads to a sharp decrease in the isokinetics of sampling and its representativeness, as well as the accuracy of control. Also, the analyzer must be protected from environmental influences and improved technical and operational characteristics.

The objective of the invention is to improve the technical and operational characteristics, namely increasing the efficiency, representativeness of sampling, accuracy and reliability of control, as well as ease of use.

The required technical result is achieved by the fact that in the method for monitoring aerosol pollution of gases, including gas extraction from the main pipeline at equal linear velocity in the gas sampling section in the main pipeline and in the inlet of the probe, the gas supply through the probe and the sampling pipe to the sampling port at the inlet which carry out gas sampling into the analyzer and into the bypass line at equal linear flow rates, simultaneously after the sampling tube, the gas velocity and pressure are reduced to their specified values at the entrance to the sampling port and analyzer, and gas for analysis and temperature control is supplied to the analyzer through a probe and a sampling tube through a single channel, the analyzer is thermostated from the bypass line by blowing it, then the thermostatic and analyzed gas is discharged into the atmosphere. In addition, the system for its implementation, comprising a probe, a sampling tube, a locking element, a conical chamber and a sampling pipe, analyzer and a bypass line coaxially placed in it with the possibility of axial movement, is equipped with a thermal container containing an analyzer inside which has an opening on its upper horizontal wall and a conical chamber coupled to it with a large base was installed; on one of the side walls a technological hatch was made with a lid tightly adjacent to the case of the thermal container and on the remaining walls there are gas-discharge openings equipped with perforated protective casings.

The authors are not aware of technical solutions with the essential features given in the characterizing part of the claims.

The invention is illustrated by drawings, where

figure 1 - distribution of flows near the holes of the sampling pipe in cases when:

a - the linear velocity of the gas at the entrance to the sampling pipe is less than the linear velocity of the gas in the sampling tube;

b - the linear gas velocity at the inlet to the sampling pipe is greater than the linear gas velocity in the sampling tube;

c - the linear gas velocity at the inlet to the sampling pipe is equal to the linear gas velocity in the sampling tube, as well as the linear gas velocity discharged to the bypass line;

figure 2 - diagram and device for the selection of gas from the main pipeline through the probe and the sampling tube to the sampling device, analyzer and thermal container;

figure 3 - connection diagram and design of the sampling device, analyzer and thermal container.

A method for monitoring aerosol pollution of gases supplied for thermostating of launch vehicles and spacecraft at the starting position is as follows.

Gas is taken from the main pipeline at an equal speed of a two-phase gas flow with solid particles in the sampling section in the main pipeline and in the inlet of the probe, while the gas is fed through the probe and the sampling tube to the sampling port, at the inlet of which gas is taken into the analyzer and into bypass line at equal linear flow rates (figure 1). After the sampling tube, the gas speed and pressure are simultaneously reduced to their preset values at the inlet of the sampling port and analyzer, and gas for analysis and temperature control is supplied to the analyzer through a probe and a sampling tube through a single channel, and the thermostat is controlled from the bypass line by blowing it , then thermostatic and analyzed gas is discharged into the atmosphere.

To implement this method for monitoring aerosol pollution of gases, a monitoring system for aerosol pollution of gases supplied through a main pipe 1 (Fig. 2) connected through an on-board detachable connection 2 is provided for blowing and thermostating of launch vehicles 3 and spacecraft 4, which contains a selection device and analysis of gas samples installed on the service tower of the launch vehicle 3 and consisting of a probe 5, a selective tube 6, a locking element - ramjet ball valve 7 (Fig.3), conical Second chamber 8 with a small taper angle (≤15 °), an open base and coaxially disposed therein with an axially displaceable nozzle sample probe 9, the analyzer 10 and bypass line 11.

The inlet of the probe 5 is facing towards the oncoming gas flow in the main pipeline 1.

The monitoring system is equipped with a thermal container 12, while the analyzer 10 is placed inside the thermal container 12 and connected to the sampling pipe 9 by a flexible pipe 13, an opening 15 is made on the upper horizontal wall 14 of the thermal container and a conical chamber 8 connected to it with a large base is installed, on one of the side walls 16 a technological hatch is made with a lid 17 tightly adjacent to the thermal container, on which there is a viewing device 18. On the remaining walls there are gas vents 19 provided with protective and casings 20 with perforation 21, representing the pinhole plate or filters. The analyzer 10 is connected remotely by a communication cable 22 with a personal electronic computer 23.

The proposed method for monitoring aerosol pollution of gases is carried out by this system as follows. When the ball valve 7 is open, thermostatic gas is taken at an equal flow rate in the gas sampling section in the main pipeline 1 - V _G and in the inlet of the probe 5-V _ol , while the gas is fed through the probe 5 and the sampling tube 6, the ball valve 7 into a conical chamber 8 to the sampling pipe 9, at the inlet of which gas is taken into the analyzer and the bypass line at equal linear flow velocities V _a = V _CR = V _b (Fig. 1c). After the selection tube in the conical chamber, the gas flow expands, the velocity V _pr and the gas pressure R _pr decrease to the specified values at the inlet to the sampling pipe 9 and the analyzer 10.

Depending on the mode - the gas flow rate for temperature control and, accordingly, the linear gas velocity in the main pipeline V _g , the linear velocity of the gas sampled through the probe and the sampling tube V _{ave also} changes. Then, taking into account a predetermined flow rate of gas through the analyzer (V _a = const) and the flow rate in the bypass line in which is provided equality V _ave = V _g, moved the sample probe inlet 9 in the axial direction to such a cross-section of the conical chamber 8, in which the ratio the areas of their cross sections S _a / S _b ensures the equality of linear velocities at the input of the analyzer and in the bypass line V _a = V _b . The amount of movement of the sampling pipe L relative to the conical chamber is determined by the nomogram, schedule or table and is controlled by a special scale plotted directly on the sampling pipe.

The lower the flow rate or gas flow rate in the main pipeline 1, the higher the sampling pipe 9 must be installed in the conical chamber 8, and vice versa, the higher the gas flow rate or flow rate, the lower. Due to the fact that the sampling pipe 9 is made with the possibility of axial movement in the conical chamber 8, it is possible to control the content of dispersed particles in a wide range of flow rates and gas velocities in the main pipeline 1.

The gas leaving the sampling device in the bypass line 11, enters through the open base of the conical chamber 8 and the hole 15 into the cavity of the thermal container 12, blows the analyzer 10 located inside it and thermostats it. The exhaust gas through the gas vents 19 of the thermal container 12 and the protective casings 20 with perforation 21 is discharged into the atmosphere.

The aerosol pollution monitoring system is designed primarily to control the purity of air in air temperature control systems (see, for example, air temperature control systems (VSOTR) in the Cosmodrome book. Under the general editorship of A.P. Volsky. M .: Voenizdat, 1977. - 309 p., Pp. 202-213). In the control of other gaseous media, the exhaust gas after exhausting through the gas outlet openings 19 of the thermal container 12 can be discharged for reuse in a closed loop.

The gas flowing through the sampling pipe 9 and the flexible pipe 13 to the input of the analyzer 10 - optoelectronic aerosol counter OEAS-05, is pumped with a given flow rate through its measuring chamber. In this case, dispersed aerosol particles cross the measuring volume illuminated by a light beam. Light pulses reflected from dispersed particles are captured by a photodetector and converted into electrical pulses, the amplitudes of which are proportional to the size of the particles; at the same time, pulses are counted - the number of particles in the required sizes and their total number.

Information on the measured counting concentration of dispersed particles during thermostating of launch vehicles and spacecraft during their preparation for launch is continuously displayed on the digital display of the analyzer 10, and is also simultaneously transmitted remotely via a communication cable 22 to a personal electronic computer 23 located at the remote control and management, where it is processed by software, is displayed on the monitor 24 and is documented.

Using a number of sampling devices and analyzers located in thermal containers, the monitoring system provides continuous simultaneous multi-channel remote control of the purity of thermostatic gases supplied through various main pipelines. In this case, aerosol particles are measured and recorded in thermostatic gases with sizes

from 0.3 microns and more;

from 0.5 microns and more;

from 5.0 microns and more

in the range of the calculated concentration from 1 to 3.5 · 10 ⁴ particles / DM ³ .

When working in remote mode provides:

- display of changes in the calculated concentration of particles on the monitor screen during the measurement in real time;

- display on the monitor screen of tables and graphs of the values of the calculated concentration of particles by sub-ranges of their sizes;

- storing the measurement results on a magnetic disk;

- printing measurement results;

- remote control of the optoelectronic aerosol counter 10.

The combination of features proposed in the invention allows to obtain a significant positive effect - the improvement of technical and operational characteristics, namely the increase in efficiency, representativeness of sampling, accuracy and reliability of control, as well as ease of use.

The invention was used in full when creating a monitoring system for air parameters SMIIV39 supplied to ensure the temperature regime of launch vehicles and spacecraft at the starting position of the spaceport.

Claims (2)

1. A method for monitoring aerosol pollution of gases supplied for thermostating of launch vehicles and spacecraft at the starting position, including gas sampling from the main pipeline at an equal linear flow rate in the gas sampling cross section in the main pipeline and in the probe inlet, gas supply through the probe and a sampling tube to a sampling pipe, at the inlet of which gas is taken into the analyzer and into the bypass line at equal linear flow rates, characterized in that after the sampling pipe The flanges simultaneously reduce the gas speed and pressure to their preset values at the inlet to the sampling port and analyzer, and the gas for analysis and temperature control is brought to the analyzer through a probe and a sampling tube through a single channel, while the thermostat is controlled from the bypass line by blowing it, then thermostatic and analyzed gases are discharged into the atmosphere. 2. A monitoring system for aerosol pollution of gases supplied for thermostating of launch vehicles and spacecraft at the launching site, comprising a probe, a sampling tube, a locking element, a conical chamber and a sampling pipe, analyzer and bypass line coaxially placed in it with the possibility of axial movement, characterized the fact that it is equipped with a thermal container containing the analyzer inside, on the upper horizontal wall of which a hole is made and a large We use a conical chamber, on one of the side walls a technological hatch is made with a lid tightly attached to the body of the thermal container, and gas vents are provided on the remaining walls, equipped with perforated protective housings.

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