RU15023U1 - SAMPLE POST - Google Patents

Description

Post Sampling

The utility model relates to air sampling devices and can be used in monitoring systems for the content of radioactive substances in the surface layer of the atmosphere.

The analogues of this utility model are known - the complete laboratory Post-1 and the air monitoring system OS3100 / 1700 2,3.

The Post-1 laboratory consists of a housing in which air sampling systems for dust, soot and gas impurities are mounted. The dust air sampling system consists of a filter holder with a filter, a heating chamber, a PC-7 rotameter, a flow regulator and an air pump (vacuum cleaner). The sampling system for gas impurities and soot consists of a pipeline with a heater and a temperature regulator, a distribution comb for connecting sorbents (absorbers) and model 822 electric aspirators.

The disadvantages of the laboratory are the inability to take air samples to determine the tritium content, the use of liquid sorbents and the lack of counters of the amount of air pumped through the system, which makes it impossible to achieve a technical result provided by the claimed utility model.

Closest to technical dryness to the claimed utility model is the air monitoring system OS3100 / 1700. This system consists of a housing in which are mounted: an aerosol sampling module and measuring their total alpha activity and an air sampling module for the subsequent determination of tritium content.

The module for selecting and measuring the total alpha activity of aerosols includes a filter holder with a filter, a measuring chamber, an electromechanical air flow regulator, an electromechanical pumped air meter, an air pump, a liquid crystal display and a set of output connectors for connecting external devices.

The tritium air sampling module consists of a flow regulator, two sets of absorbing containers, between which a heated catalyst is located, traps for trapping droplets of absorbers, an electromechanical flow meter, an air pump, a liquid crystal display and a set of output connectors for connecting external devices.

The disadvantages of this system are:

1. The presence of a system for measuring the total alpha activity, which significantly complicates the system, requiring the use of a metering gas and, as a result, the use of a special device in the system that automatically connects the module to the atmosphere during unplanned power outages.

2. The use of harmful chemicals in the liquid state as tritium absorbers, which, firstly, imposes additional safety requirements for the maintenance of the system, and secondly, requires the use of a special device to trap the drops of the absorber in order to prevent pollution and breakdown of the pumping equipment .

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These shortcomings greatly complicate the manufacture and maintenance of this system, increase its cost, and also impose additional safety requirements for system maintenance.

The technical problem to which the claimed utility model is directed is to take air samples from the surface layer of the atmosphere for subsequent determination in laboratory conditions of the average concentration of radioactive substances during the exposure of the samplers.

The technical result of the application of this utility model is:

1. Reducing the cost of manufacturing a post.

2.Easy to manufacture and operate.

3. Improving the safety of maintenance work.

4. Improving reliability.

The technical result is achieved by the fact that in a known sampling station comprising a housing in communication with ambient air, in which an aerosol extraction system including an aerosol filter and an air flow meter is located, a tritium water vapor extraction system including a vapor absorption unit, an air flow meter, an element that sets the air flow, while both systems are connected to the same air pump, and the tritium extraction unit in the form of gas, the water vapor absorption unit is a column filled with a solid sorbent m of water vapor, and a rotameter is selected as the element determining the air flow, the tritium sampling unit in the form of a gas is a container filled with a solid oxidizer, providing low-temperature oxidation of hydrogen and a solid sorbent of water vapor, communicated with the surrounding air through openings made on two opposite the ends of the tank, the post body is divided by a partition into two zones, in one of which sampling systems are located, in the other - an air pump and electrical equipment that ensure the operation of the systems of the assembly, the message of the post body with the surrounding air is carried out using windows on which inclined blinds are installed.

As a sorbent of water vapor, synthetic zeolite can be selected. The water vapor recovery system may be equipped with a dust absorber. The holes in the tank for sampling tritium in the form of gas can be made of different diameters and have plugs that could be installed on any of the holes depending on the selected exposure time of the sampler.

The technical result is achieved due to:

-simplification of the functional diagram. In the claimed model (in contrast to the known 2) there is no function for measuring the total alpha activity. In addition to reducing the cost of manufacturing and operation, due to the refusal to use this function, the use of metering gas is excluded. As a result of this, there is no need for additional devices to prevent excessive pressure buildup in the measuring chamber.

- the use of solid non-toxic sorbents for the absorption of tritium in the form of water vapor and in the form of gas. As a result, the possibility of contact of maintenance personnel with harmful chemicals is excluded, and the need to protect the pumping equipment from droplets of the absorber carried away by the air flow passing through the system is also eliminated.

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-replacements of the heated catalyst with a catalyst that provides oxidation of hydrogen at ambient temperature, which eliminates the risk of burns for maintenance personnel.

-divisions into zones of the workspace of the post. The working space of the post is divided by a partition into two compartments - sampling and instrument. The latter houses electrical equipment and an air pump. With this arrangement, the possibility of contact of maintenance personnel with electrical equipment when changing samplers is excluded.

- the use of predominantly mechanical devices for defining, maintaining and accounting for air flow through sampling devices, i.e. rotameter and gas meters, which increases the reliability of the system in the blank.

In fig. 1 shows a functional diagram of the claimed utility model.

The sampling station consists of a building 1 with windows 14 and 15, closed by inclined shutters, divided by a partition into two compartments - sampling 2 and instrument 3, in which are located:

- an aerosol selection system including a filter holder 4 with an aerosol filter 5 and an air flow meter 6;

- tritium water vapor selection system, including a vapor absorption unit 8, a dust absorber 9, an air flow meter 10, a rotameter 11 with a control valve 12;

- inlet pump 7, to which both systems are connected;

- tritium sampling unit in the form of gas 13.

The post works as follows. When the air pump 7 is turned on, air through the windows 14 in the housing of the post 1 enters the sampling compartment 2, passes through the filter 5 and the column 8 filled with a solid sorbent of water vapor, a dust absorber 9, an air flow meter 10, a rotameter 11, a control valve 12, a counter air flow 6 and is ejected by the pump 7 through the window 15 in the instrument compartment 3 outside the housing of the station 1. The operation of the tritium sampling unit in the form of gas 13 is based on the absorption of hydrogen and water vapor entering the unit due to diffusion of air through openings of different diameters on opposite ends of the block. Moreover, depending on the selected exposure time of the sampler, it is possible to change the diffusion rate of air. With both openings, the diffusion rate will be maximum, with the smaller of the openings, the minimum. By closing either one or the other hole with a plug, you can change the value of the diffusion rate. Thus, during the operation of the post, the aerosols contained in the air are deposited on the filter 5, and water vapor is absorbed by the sorbent in column 8. In the tritium extraction unit in the form of gas 13, hydrogen gas and tritium are oxidized and the resulting water is absorbed. After a predetermined exposure time, the air pump is turned off, the sampling devices are replaced, and the exhibitors are delivered to the laboratory to determine the average concentration of radioactive substances in the surface layer of the atmosphere during the exposure of the samplers.

According to the scheme of the claimed utility model, an experimental version of the sampling post was made. For the manufacture of the frame and the walls of the body of the post used wooden blocks and plywood. Petryanov’s fabric of the FPP-15-1.7 brand was used as a material for the aerosol filter, synthetic NaA zeolite was used for water vapor absorption, cotton was used for dust absorption

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filter. Air flow was established and regulated using a mechanical rotameter with local indications of the grade PM-A-0,063 GUZ (GOST 13045-81), equipped with a control valve. The volume of air pumped through the aerosol sampling system was measured using a NP-G4 type G4 mechanical gas meter (TU 4213-001-00467146-98). The volume of air pumped through the water vapor extraction system was measured using a Premagas G2.5 MKM membrane gas meter, which is certified by the State Standard of the Russian Federation on type approval as a measuring instrument (SI) and entered in the State Register of SI. A ventilation unit of the AP-600M brand (TU 16-632.631-84) of a household vacuum cleaner connected through a flange to an induction electric motor of the AIR 56 Ш2ВЗУЗ / IM2181 brand (GOST 16264.1-85) was used as an air pump. As a catalyst for low-temperature oxidation of hydrogen and a sorbent of water vapor in block 13, a palladium catalyst based on active aluminum oxide of the APN grade (TU 6-02-7-228-89 Izv. 1,2,) was used.

Trial operation of the post for 6 months. During the operation period, not a single failure of the devices used was recorded and laboratory averages of the concentration of radioactive substances in the surface layer of atmospheric air during the exposure of the samplers were determined. Moreover, during operation, the following environmental characteristics were noted: air temperature - from minus 26 ° С to plus 32 ° С; relative humidity - from 40 to 90 percent. Thus, the claimed technical problem is expanded and the possibility of obtaining the claimed technical results is confirmed.

Sources of information:

1. Guidelines for the control of air pollution. RD 52.04.186-89.- M., Goskomhydromet USSR, 1991.

2.EG & G ORTEC® Air Monitoring Systems. - Oak Ridge, TN 37831-0895, 1996. / EG&G ORTEC Air Monitoring Systems. Prospectus in English lang Materials of the exhibition Radiation Safety -99, St. Petersburg, November 11, 1999./.

3.EG & G ORTEC® OS1200 / OS1700 Collectors. - Oak Ridge, TN 37831-0895, 1996. / OS1200 / OS1700 Samplers from EG&G ORTEC. Prospectus in English lang Materials of the exhibition Radiation Safety -99, St. Petersburg, November 11, 1999 /.

Claims (4)

1. A sampling station containing a housing in communication with ambient air, in which an aerosol extraction system is located, including an aerosol filter and an air flow meter, a tritium water vapor sampling system, including a vapor absorption unit, an air flow meter, an element that sets the air flow, this, both systems are connected to one air pump, and a tritium extraction unit in the form of a gas, characterized in that the water vapor absorption unit is a column filled with a solid sorbent of water vapor, and as an element a gas flow rate specifying gas flowmeter is selected; the tritium gas sampling unit in the form of a gas is a container filled with a solid oxidizing agent that provides low-temperature oxidation of hydrogen and a solid sorbent of water vapor, communicated with the surrounding air through openings made on two opposite ends of the tank, the case body divided by a partition into two zones, in one of which sampling systems are located, in the other - an air pump and electrical equipment that ensures the operation of sampling systems, communication of the post building with narrowing air is carried out using windows on which inclined shutters are installed.  2. The sampling post according to claim 1, characterized in that synthetic zeolite is selected as the sorbent of water vapor.  3. The sampling post according to claim 1 or 2, characterized in that the tritium water vapor extraction system is equipped with a dust absorber. 4. The sampling post according to claim 1, or 2, or 3, characterized in that the openings in the container for taking tritium in the form of a gas are made of different diameters, have plugs that can be installed on any of the ends depending on the selected exposure time for this sampler.