WO2019132725A1

WO2019132725A1 - Sample collector for the representative sampling of a gaseous aerosol medium from an exhaust flue

Info

Publication number: WO2019132725A1
Application number: PCT/RU2018/000850
Authority: WO
Inventors: Александр Евгеньевич ШЕРМАКОВ; Николай Михайлович ВЛАСКИН; Константин Владимирович РОДИОНОВ
Original assignee: Акционерное общество "КБ "Проминжиниринг"
Priority date: 2017-12-26
Filing date: 2018-12-21
Publication date: 2019-07-04
Also published as: RU2684601C1

Abstract

The invention relates to devices for use in sampling systems. A sample collector comprises: a bundle of sampling tubes of different lengths with bent ends, on which nozzles with sampling tips are mounted; a mixing chamber having a body in the form of a hollow vessel, the base of which is connected to the opposite ends of the bundle of sampling tubes from the bent ends with the nozzles; and a length of pipe, a first end of which is connected to the apex of the mixing chamber, and a second end of which forms an outlet of the sample collector. The bundle of sampling tubes of the sample collector is adapted for placement inside an exhaust flue, by installation via an opening in the wall of the exhaust flue, in a position in which the axes of the inlet openings of the nozzles are parallel to the longitudinal axis of the exhaust flue and are oriented counter to the flow of air therein. The lengths of the sampling tubes are selected such that each of the nozzles disposed at the ends thereof is situated inside one of the zones, in the form of concentric rings of equal area, into which the cross section of the exhaust flue is notionally divided at the point at which the nozzles are situated, the number of said zones being equal to the number of sampling tubes in the bundle. The technical result is an increase in the representativeness of the sampling of gaseous aerosol mediums from industrial exhaust flues, thus providing a more accurate assessment of the effect of industrial emissions on the environment and improving public safety.

Description

SAMPLING COLLECTOR FOR THE REPRESENTATIVE SELECTION OF A GAS-AEROSOL MEDIA FROM A TUBE PIPE

TECHNICAL FIELD

The present invention relates to devices used as part of sampling systems, which provide a representative selection of air containing aerosols from waste pipes of industrial facilities, for example, nuclear power plants, for subsequent transportation through the bypass and mounting pipes through a sampling pipeline to the filter assembly, trapping aerosols from controlled air, for subsequent measurement of their physical characteristics.

In particular, the invention can be used to provide a representative sampling of the gas-aerosol medium from the ventilation pipe of a nuclear power plant (hereinafter referred to as “NPP”) while monitoring emissions of NPPs (when measuring volumetric activities and daily radioactive emissions of aerosols and radionuclides of iodine).

An important condition for taking a sample from a waste pipe is its representativeness, which is ensured when part of the gas-aerosol medium taken from the discharge pipe most accurately reflects the concentration and distribution pattern of aerosols in the medium flow in the waste pipe. The representativeness of sampling should be ensured by simultaneous compliance with the following measures:

- isokinetic sampling, i.e., the equality of the flow rate of the gas-aerosol medium in the discharge pipe at the sampling site and the velocity of the gas-aerosol medium at the inlet of the sampling element of the sampling collector;

- the optimal distribution of sampling tubes of the sampling collector over the cross-section of the waste pipe (ie, the choice of their locations over the cross-section of the pipe);

- optimal aerodynamic characteristics of the sampling tubes and mixing chamber of the sampling collector, since the design of the nodes the sampling collector should not introduce significant aerodynamic disturbances at their locations in the discharge pipe;

- sampling units should have small geometrical dimensions compared with the size of the controlled waste pipe in order not to introduce large disturbances to the stream of air drawn from the waste pipe;

- exclusion or minimization of the process of moisture condensation inside the sampling path along its entire length from the sampling point from the controlled waste pipe to the final sample delivery point.

BACKGROUND

The prior art known solutions.

A known sampling manifold containing sampling tubes with a collecting chamber connected to them. The sampling collector is designed to be placed in a controlled pipeline in order to take a liquid sample from it in proportion to the flow of the controlled liquid in the pipeline and further transportation and return it through the bypass connection back to the pipeline. Sampling tubes of the sampling collector are made and placed in such a way that the sampling of the liquid is carried out over the entire cross section of the pipeline being monitored. A bypass pipeline containing a mixer and a fluid flow regulator is connected to a mounting pipe intended for withdrawing a sample through a metering device connected to the analyzer. With the help of a fluid flow regulator, the isokinetic character of sampling from a controlled pipeline is ensured (SU 1280464, publication date 12/30/1986).

The known sampling collector does not ensure the representativeness of the sampling when it is used for sampling gas-aerosol media from pipelines, since it does not disclose technical means that would ensure the optimal aerodynamic characteristics of the sampling elements, resulting in a controlled flow of gas-aerosol on them disturbances will be introduced into the flow of the medium and into the distribution of aerosols in it, thereby disrupting the representativeness of sampling. In addition, for such Sampling collector has not determined the optimal distribution conditions of sampling tubes over the cross section of the waste pipe. Since the distribution of the velocity of the controlled flow of the gas-aerosol medium and the concentration of aerosols vary over the cross-section of the discharge pipe, it is important to arrange the sampling tubes over its cross-section so that the weights of the samples of the gas-aerosol medium entering the collection chamber of the sampling collector from all the sampling tubes were equal. The fulfillment of this condition is one of the important conditions for representative sampling. The achievement of the remaining conditions of representativeness of sampling is also not disclosed in the description of the known collector.

Thus, the main disadvantage of the known sampling collector is that it cannot provide high representativeness of continuous sampling, including in the case of using it for sampling the gas-aerosol medium from the waste vent pipe, because of all the above representative sampling conditions, only how is only isokinetic sampling achieved using a known collector.

Known sampling collector, designed for placement in a controlled pipe for the selection of gas-aerosol samples and transport it through the bypass pipe to the duplicate measuring systems. The collector is made in the form of a single sampling tube with fittings distributed along its length. The collector is connected to a bypass pipe containing a filter unit that traps radioactive aerosols and iodine contained in the sample taken, and a gas sampler that receives gaseous radioactive materials and where their parameters are measured, as well as a regulator that adjusts the flow rate for isokinetic gas extraction samples. After measurement, the sample is returned to the controlled pipe (JPS5748634, publication date 03/20/1982).

When using the well-known sampling collector for sampling gas-aerosol medium from the exhaust vent pipe also, as in the previous case, the optimal aerodynamic characteristics of the sampling elements are not provided, as a result, when a controlled gas-aerosol medium rushes onto them, a disturbance is introduced into the medium flow and, consequently, a low representativeness of the gas-aerosol environment sampling from the waste pipe is achieved. In addition, this design of the sampling collector does not provide isokinetic sampling and, consequently, obtaining a representative sample when sampling from large-diameter ventilation pipes (for example, from 1000 mm and above), because the fittings are distributed along the entire length of the sampling tube, which ensures isokinetic sampling only in controlled pipes of small diameter (for example, from 300 to 1000 mm), since when using a well-known collector, the vacuum in the inlets of the fittings, due to which the controlled gas is taken, will decrease towards the removal of the fittings from the junction of the sampling tube to the bypass branch pipe. Also, the design of a well-known sampling collector does not provide the possibility of carrying out its routine maintenance and repair work, since it does not provide mechanisms for extracting a sampling tube with fittings from a controlled pipe.

Thus, the main disadvantage of such a sampling collector is that it cannot ensure the high representativeness of continuous sampling of the gas-aerosol medium from the vent vent for the same reasons as in the previous case.

The closest analogue of the claimed invention is a sampling collector designed for sampling hydrocarbon compounds from a controlled pipeline when used as part of a sampling device (RU2249193, published March 27, 2005). The sampling collector consists of a mixing chamber with a flange and five sampling tubes connected to it, designed to be placed throughout the cross section of the pipeline being monitored and to continuously take a portion of the flow of the controlled medium through them. Sampling tubes have bent ends designed to arrange them vertically along diameter of the controlled pipeline. The axes of the inlets of the bent ends of the sampling tubes are parallel to the longitudinal axis of the pipeline being monitored and directed towards the flow and separated from each other by a distance of 0.2 of the pipeline diameter, while the inlet of the central tube is located on the axis of the pipeline being monitored. The diameters of the sampling tubes to the center of the pipeline are reduced in accordance with the ratio of 26:20:12. The opposite ends of the intake tubes are connected to a mixing chamber designed to be connected to the bypass inlet to transport part of the flow through it from a controlled pipeline through the sampling manifold under excessive pressure, and return the selected stream back to the controlled pipeline. The bypass outlet is connected to a controlled pipeline downstream than the sampling collector is located. A flow regulator is installed on the bypass pipe, which ensures its adjustment through means of measuring flow parameters (a means of measuring density, temperature, pressure) for the isokinetic character of sampling of the medium from the monitored pipeline.

Known sampling collector may be used for the selection of liquid and gas-aerosol medium. However, when describing its design, as well as in the description of the device, known from SU1280464 (publication date 12/30/1986), the technical means for providing the following parameters are not defined:

- optimal aerodynamic characteristics of sampling elements, which leads to the fact that when a controlled gas-aerosol medium rushes in on them, disturbances will be introduced into the flow of the medium, thereby disrupting the representativeness of sampling;

- optimal conditions for the distribution of sampling tubes over the cross section of the waste pipe. Since the distribution of the velocity of the controlled flow of the gas-aerosol medium and the concentration of aerosols vary over the cross-section of the discharge pipe, it is important to arrange the sampling elements along its cross section so that the weights of the samples of the gas-aerosol medium entering the collection chamber of the sampling collector from all sample tubes , were equal. Meeting this condition is also one of the important conditions for representative sampling.

In addition, the collector does not provide for the exclusion or minimization of moisture condensation inside the sampling path all the way from the sampling point from the controlled waste pipe to the final sample delivery point, where measurements of parameters of the controlled medium are carried out, which in the case of using the device for sampling gas-aerosol samples to the deposition of aerosols on the walls of the sampling path and, therefore, leads to incorrect measurement results.

Thus, the main disadvantage of such a sampling collector is that it does not ensure the high representativeness of continuous sampling of the gas-aerosol medium from the waste pipe.

DISCLOSURE OF INVENTION

The technical problem of the present invention is the need to overcome the technical shortcomings inherent in the analogs, which leads to the need to create an effective sampling collector that would provide improved operational and technological characteristics with effective sampling of gas-aerosol samples from the waste pipe.

The technical result of the claimed invention is to increase the representativeness of the sampling of the gas-aerosol environment from the waste pipe of an industrial facility, which improves the accuracy of the assessment of the impact of emissions from an industrial enterprise on the environmental state of the environment and increase public safety.

The technical result is achieved due to the execution of a sampling collector (1) intended for sampling a gas-aerosol medium from a discharge pipe containing a bundle of sampling tubes (4) of different lengths with curved ends, on which nozzles (5) with sampling ends are installed; mixing chamber (6) with a housing in the form of a hollow vessel, the base of which is connected to the ends of the bundle of sampling tubes (4) opposite to the folded ends with fittings (5); pipe section (7), one end of which is connected to the top of the mixing chamber (6), and the second the end is the outlet of the sampling collector (1), and the bundle of sampling tubes (4) of the sampling collector (1) is designed to be placed inside the discharge pipe by placing it through the opening in the wall of the discharge pipe in a position where the axes of the inlets of the fittings (5) are parallel to the longitudinal the axis of the discharge pipe and directed towards the air flow in it, while the length of the sampling tubes (4) are chosen so that each of the fittings (5) installed at their ends is located inside one of the zones in the form of concentric Sgiach rings of equal area, which conventionally broken cross section bleed pipe at the location of connections (5), and whose number is equal to the number of sampling tubes (4) in the beam.

Due to the presence in the composition of the sampling collector (1) beam consisting of separate sampling tubes (4), each of which is connected at one end to the mixing chamber (6), is almost the same vacuum at the ends of all fittings (5) and, accordingly, almost the same flow rates of the controlled medium at the entrance to each of the nozzles (5), which is a condition for increasing the representativeness of sampling for waste pipes of any diameter (both small, with a diameter, for example, less than 1000 mm, and large diameter, Example, more than 1000 mm), in contrast to, for example, the design of the sampling collector, known from the patent JPS5748634 (publication date 03/20/1982), with one sampling tube, on which the fitting is installed along the entire length, when using the sample when sampling the medium the vacuum drop at the suction ends of the nozzles along the length of the sampling tube, which leads to a corresponding drop in the flow rate of the media when entering the nozzle, and the more it is located further from the junction of the sampling tube with the mixing chamber. If for small-diameter discharge pipes (up to 1000 mm) this effect is not so noticeable, then for large-diameter pipes (for example, such as NPP ventilation pipes, whose diameter ranges from 2000 to 3000 mm), the difference in speeds becomes noticeable and leads to significant deterioration of representativeness of sampling. By performing the ends of the sampling tubes (4), bent in such a way that the axes of the inlets of the nozzles (5) are parallel to the longitudinal axis of the discharge pipe towards the air flow in it, the disturbance of the flow of the medium is minimized when they run into the nozzle and thereby increases the representativeness of sampling .

By choosing different lengths of sampling tubes (4) so that each of the fittings (5) installed at their ends is located inside one of the zones in the form of concentric rings of equal area, into which the cross-section of the waste pipe is conventionally divided at the location of the fittings (5 ), and the number of which is equal to the number of sampling tubes (4) in the beam, simultaneous sampling of the gas-aerosol medium from different flow zones in the waste pipe, where all the selected samples have the same weighting factors, and further post penetration into the mixing chamber (6) of the sampling collector (1) of gas-aerosol medium samples from all sampling tubes (4), which leads to the most representative sampling over the cross-section of the waste pipe and, as a result, the accuracy of estimation of the impact of industrial emissions on the ecology increases external environment and increase the safety of the population.

Thus, the claimed design of the sampling collector provides increased representativeness of the sample during its operation.

In the particular case of the implementation of the claimed invention, the sampling collector may be intended for use as part of a radiation monitoring system for the release of radioactive aerosols, gases and iodine through a vent pipe at nuclear facilities.

The mixing chamber (6) can be made in the form of a hollow truncated cone with a taper angle equal to, for example, 15 ° -30 °. The top of the mixing chamber is connected to the pipe section, and has external and internal diameters corresponding to the external and internal diameter of the bypass branch pipe, which ensures a smooth, without sudden jumps, the mixing of air samples from the sampling tubes into the mixing chamber and its delivery in the bypass pipe, and thereby minimizes the loss of radioactive aerosols and iodine in the mixing chamber due to inertial deposition.

The mixing chamber (6) can be coaxially connected to the pipe segment (7) by welding.

The mixing chamber (6) and a length of pipe (7) connected to it can be designed for use with a mounting flange (14) installed and fixed at their joint by welding.

The base of the mixing chamber (6) can be connected to the beam of sampling tubes (4) by welding.

A bundle of sampling tubes (4) connected to the base of the mixing chamber (6) may be designed for use with the plug (17) installed at the junction of their connection. The plug (17) can be made round.

The longitudinal axis of the pipe section (7) and the mixing chamber (6) together with the beam of sampling tubes welded to it (4) can be shifted downward relative to the axis of the plug (17) and to the axis of the mounting flange (14), which ensures the placement of the sampling collector inside the controlled waste pipe in such a way that the nozzles (5) of the sampling tubes will be located below the edge of the hole in the wall of the waste pipe through which the sampling collector (1) is installed inside the waste pipe and the inlets of the nozzles are directed towards the flow air in the waste pipe. This solution allows the location of the fitting (5) closest to the wall of the waste pipe to eliminate the influence of aerodynamic disturbances on it when air flows along the opening in the wall of the waste pipe.

Each of the input sections (ends) of the sampling tubes (4) can be bent at a right angle with respect to the corresponding sampling tube (4), the bend of the ends of the sampling tubes (4) with the fittings (5) mounted on them can be made with a radius equal to at least five internal diameters, which minimizes the inertial deposition of aerosols during transportation of the gas-aerosol sample along the bends of the sampling tubes, and thus also minimizes the loss of radioactive aerosols and iodine due to their inertial deposition during transportation through the sampling pipeline to the equipment for monitoring gas and aerosol emissions, which increases the representativeness of the sample.

The distance from the inlet openings (ends) of the sampling tubes (4), on which nozzles (5) are installed, to the straight sections of the respective sampling tubes (4) can be at least five internal diameters of the sampling tubes (4), which eliminates the influence of aerodynamic disturbances, occur when air flow rushes to the straight sections of sampling tubes (4), to the air flow in places where it flows onto the choke (5) and thereby increases the representativeness of the gas-aerosol medium sampling (5) of the sampling tubes (4).

The sampling end of each fitting (5) can be made in the shape of a truncated cone, the apex of which is intended to direct it towards the air flow in the waste pipe. The angle of taper of each fitting (5) can be 15-30 °, the narrow part of which is directed towards the air flow in the waste pipe, which ensures that the flow direction of the aerosols is retained when the air flow rushes to the choke (5) and thereby increases the representativeness of gas sampling aerosol medium by fittings (5) sampling tubes (4).

The magnitude of the cross-sectional area of the inlet of the nozzle (5) with an accuracy of relative error d can be determined by the following expression:

where: s _BX - the cross-sectional area of the inlet of the nozzle (5), cm ² ;

w is the bleed air flow rate through the sampling tube (4), cm ³ / min,

W si

W =

n (2)

WCM is the nominal bleed air flow rate through the mixing chamber (6), cm ³ / min,

p is the number of sampling tubes (4) in the beam,

V is the linear velocity of air over the internal section of the waste pipe at the location of the fittings (5) of the sampling tubes (4), cm / min,

W „- the average for the modes of operation of an industrial facility air flow in the waste pipe, cm ³ / min,

S is the area of the internal cross-section of the pipe at the location of the fittings (5) of the sampling tubes (4), cm ² ,

d = 1, 1 (5 ² WC _M ⁺ 5 ² WB _T ) ^1/2 _> (4)

6W _CM - relative error of maintaining the air flow through the mixing chamber (6) relative to the nominal air flow,%

6W _BT - relative dispersion of air flow in the waste pipe relative to the average air flow rate of an industrial facility,%.

This embodiment of nozzles (5) ensures the equality of the air flow rate at the point of its entry into the nozzle (5) at each sampling point of controlled air and the average air flow rate in the waste pipe in the vicinity of each nozzle, which ensures the achievement of the principle of isokinetic sampling (when the suction flow rate on sections of fittings (5) of the sampling tubes (4) is equal to the flow rate of the controlled medium in the waste pipe).

Sampling manifold (1) may contain five sampling tubes (4) in a bundle.

The sampling tubes (4) in the beam can be rigidly fastened together in pairs with the help of staples (19), which significantly increases the rigidity of the entire beam of sampling tubes, resistance to vibration and to the aerodynamic effects of controlled air, which also further enhances the representativeness of gas-aerosol sampling environments by fittings (5) sampling tubes (4).

The output of the sampling collector (1) may be designed to be connected to a bypass connection (2) located outside the discharge pipe.

The end of the pipe section (7) can be designed to be connected to the first end of the bypass pipe (2) by means of flanges (8) and (9) installed on their mating ends, respectively. The second end of the bypass pipe (2) can be designed to connect to the mounting pipe (3), which is intended to connect to it a sampling pipe for transporting the selected medium to the equipment for monitoring gas-aerosol emissions.

The bypass connection (2) can be designed to connect it to the mounting connection (3) using the flanges (10) and (11) installed on their mating ends, respectively.

The mounting pipe (3) can be designed to be connected in series to its second end by welding a sampling pipe, through which the gas-aerosol medium is transported to the equipment for monitoring radioactive emissions from the waste pipe.

The internal diameter of the top of the hollow truncated cone of the mixing chamber (6) may correspond to the internal diameter of the bypass connection (2).

The internal diameter of the pipe section (7) may correspond to the internal diameter of the apex of the hollow truncated cone of the mixing chamber (6) and the internal diameter of the bypass branch pipe (2).

The mounting pipe (3) can be designed to be placed inside the waste pipe for connection to its second end of the sampling pipeline, through which the gas-aerosol medium is transported to the radioactive emission control equipment from the waste pipe, at its first end, which is connected to the second by the end of the bypass pipe (2), outside the waste pipe, by mounting the installation pipe (3) through the hole in the wall of the waste pipe, which is located below the hole for placement beam sampling tubes (4) sampling manifold (1).

The inner diameter of the upper assembly of the pipe (12) is selected so that a bundle of sampling tubes of the sampling collector (1) passes into it.

A hole in the wall of the waste pipe, designed to install through it a bundle of sampling tubes (4), can be made on the section to which the upper mounting piece of pipe (12) is attached, and the bottom the hole in the wall of the waste pipe, designed to install through it the mounting pipe (3), can be made in the area to which the lower mounting pipe (13) is attached, and said holes can be made with diameters corresponding to the outer diameters of the above (12 ) and lower (13) mounting pipe lengths. Due to this implementation, it is possible to carry out work on the installation / disassembly of its individual components during routine maintenance and repair of the sampling collector (1), and also makes it possible to lay the main part of the sampling pipeline inside the waste pipe, which minimizes cooling of the extracted air during its transportation through the sampling the pipeline from the sampling point to the final point where the means for measuring the volumetric activity of aerosols and iodine contained emissions from the waste pipe. This eliminates the possibility of condensation and, as a consequence, the deposition of radioactive aerosols and iodine on the inner wall of the sampling pipeline, which further increases the representativeness of the sampling.

Upper (12) and lower (13) pipe fittings can be made with flanges (15), (16), respectively, for connecting them to the mounting flange (14) of the sampling collector (1) and to the flange (10) at the end of the bypass connection ( 2) respectively.

The upper (12) and lower (13) pipe fittings with flanges (15), (16), respectively, can be attached to the wall of the waste pipe by welding.

The bypass connection (2), the lower (12) and the upper (13) mounting pieces of pipes can be designed to be covered with thermal insulation material (18).

The bypass connection (2) can be made U-shaped. In this case, the bends of the bypass pipe (2) can be made with radii equal to at least five of its internal diameters. The mounting pipe (3) can be made L-shaped. The bend of the mounting pipe (3) can be made with a radius equal to at least five of its internal diameters. Perform bypass U-shaped pipe and mounting L-shaped pipe with by the above bends minimizes the inertial deposition of aerosols of the gas-aerosol sample during its transportation along the bends and thus also minimizes the loss of radioactive aerosols and iodine during transportation to the equipment for controlling gas-aerosol emissions.

The bypass pipe (2) and other elements of the sampling path, made in this way, have optimal aerodynamic characteristics, since the design of sampling nodes that are part of the sampling device should not introduce significant aerodynamic perturbations at the locations of the sampling nodes.

When the bypass pipe (2) is located, which is small and U-shaped, it is possible to lay the sampling pipe inside the controlled waste pipe outside the discharge pipe and cover it with insulating material, which ensures the minimum difference between the temperature of the selected air and the temperature of the controlled air inside the waste pipes along the entire length of the sampling pipeline. This prevents condensation of moisture contained in the controlled air inside the sampling tract along its entire length from the sampling point of the controlled ventilation pipe to the final sample delivery point (gas aerosol emission monitoring equipment), which also minimizes the loss of radioactive aerosols and iodine.

The sampling collector (1), the bypass branch pipe (2) and the mounting branch pipe (3) can be made of stainless steel, and the upper (12) and lower (13) mounting pipes can be made of the same steel grade as the waste pipe , and the sampling collector (1), the bypass branch pipe (2) and the assembly branch pipe (3) can be made with an electrochemically polished inner surface, which ensures low sorption of the transported sample and thus minimizes the loss of radioactive aerosols and iodine during their transportation to equipment Hovhan gas aerosol emissions control and, therefore, increases the representation of sampling. DESCRIPTION OF THE DRAWINGS

The claimed invention is illustrated by drawings, which depict the following:

Figure 1 - sampling collector a) side view, b) top view, figure 2 - section fitting,

in fig. 3 - bypass branch pipe with a flange for connecting a pipe section (7) and a flange for connecting a mounting pipe (3),

in fig. 4 - mounting pipe with flange,

in fig. 5 - upper mounting pipe with a flange,

in fig. 6 - lower mounting pipe segment with a flange,

in fig. 7 - section of the bracket connecting the sampling tube,

in fig. 8 is a diagram of placement in the ventilation pipe of the sampling collector as part of the sampling device assembly,

in fig. 9 is a diagram explaining the conditional division of the cross section of a ventilation pipe into five zones in the form of concentric rings of equal area, where: Si = S ₂ = S ₃ = S ₄ = S ₅ .

Positions on the figures indicated:

1 - sampling collector,

2 - bypass connection,

3 - mounting pipe

4 - sampling tubes,

5 - fitting,

6 - mixing chamber

7 - pipe section

8 - connecting flange at the end of the pipe cut (7) for connection with the connecting flange (9) located at the first end of the bypass connection (2),

9 - connecting flange at the first end of the bypass pipe (2) for connection with the connecting flange (8) located at the end of the pipe section (7),

10 - connecting flange at the second end of the bypass connection (2) for connection with the first end of the installation connection (3), 11 - connecting flange on the first end of the mounting pipe (3) for connection to the second end of the bypass pipe (2),

12 - upper mounting pipe segment,

13 - lower pipe installation section,

14 - mounting flange at the junction of the mixing chamber (6) and pipe section (7) for connection to the upper pipe installation segment (12),

15 - flange of the upper mounting pipe (12) for connection to the mounting flange (14),

16 - the flange of the lower assembly of the pipe (13) for connection with the connecting flange (10),

17 - plug placed at the junction of the beam sampling tubes (4) and the base of the mixing chamber (6),

18 heat insulation,

19 - bracket.

The sampling manifold (1) contains a bundle consisting of five sampling tubes (4) connected by means of brackets (19). The tubes in the bundle are made of different lengths with the ends bent at a right angle. At the bent ends of the sampling tubes (4) are installed fittings (5) with sampling ends. A bundle of sampling tubes (4) is connected in series with the mixing chamber (6) and with the end of a pipe segment (7); a round cap (17) is installed at the junction of the joint. The opposite end of the pipe cut (7) is the output of the sampling collector (1) and contains a flange (8) for connection to the end of the bypass connection (2). At the junction of the mixing chamber (6) and the pipe section (7) there is a mounting flange (14) for connecting the upper (12) pipe mounting section (figure 1).

The sampling end of the fitting (5) mounted on the end of the sampling tube (4) is made in the shape of a truncated cone, the apex of which is intended to direct it towards the air flow in the waste pipe (figure 2).

The sampling collector (1) is connected in series with the U-shaped bypass branch pipe (2) and with the L-shaped mounting branch pipe (3). The first end of the bypass pipe (2) is connected to the mounting pipe (3) by means of flanges (8) and (9) installed on their mating ends, respectively (Fig. 3).

The second end of the bypass pipe (2) is designed to connect it to the mounting pipe (3) by means of flanges (10) and (11) installed on their mating ends, respectively (Fig. 4).

The output of the sampling collector (1) is designed to place it inside the upper assembly of the pipe (12) with a flange (15) located on the section of the pipe wall with the top opening (figure 5).

The first end of the mounting pipe (3) is designed to place it inside the lower mounting section of the pipe (13) with a flange (16) located on the section of the pipe wall with the bottom hole (Fig.6)

Sampling tubes (4) are pairwise interconnected by brackets (19) (Fig. 7).

The sampling device assembly contains a sampling manifold (1), partially placed inside the discharge pipe through the upper opening in its wall, a bypass connection (2) located outside the waste pipe, and a mounting connection (3), the first end of which is connected to the end of the bypass connection ( 2) outside the waste pipe, and the second end is placed inside the waste pipe through the bottom opening in its wall and connected to the sampling pipeline, through which the gas-aerosol medium is transported to the control equipment happy oaktivnyh emissions.

On the wall of the waste pipe one above the other in the areas where the upper and lower holes are made, the upper (12) and lower (13) mounting pieces of pipes are fixed. A bundle of sampling tubes (4) of the sampling collector (1) is placed inside the discharge pipe by installing it through the top opening. The first end of the mounting pipe (3), which is connected to the end of the bypass pipe (2), is placed inside the waste pipe by fitting it through the bottom opening. The upper (12) and lower (13) pipe fittings contain flanges (15), (16), respectively, attached to the mounting flange (14) of the sampling collector (1) and to the flange (10) at the end of the bypass connection (2), respectively. The longitudinal axis of the pipe segment (7) and the mixing chamber (6) together with the beam welded to it The sampling tubes (4) are displaced downward relative to the longitudinal axis of the plug (17) and to the longitudinal axis of the mounting flange (14). The fittings (5) are located below the top hole in the wall of the waste pipe.

The mounting pipe (3) is intended for the successive connection of its second end by welding to a sampling pipeline through which the gas-aerosol medium is transported to the equipment for monitoring radioactive emissions from the waste pipe.

The bypass connection (2), the lower (12) and upper (13) mounting pieces of pipes are covered with insulating material (18).

The lengths of the five sampling tubes (4) are chosen so that each of the fittings (5) installed at their ends is located inside one of the five conventional zones at a distance C, l_ ₂ , L ₃ , l_ ₄ , 1_ ₅ from the pipe wall, in which made the upper and lower holes (Fig.8).

The conditional zones are concentric rings of equal area Si = S ₂ = S ₃ = S ₄ = S ₅ , into which the cross section of the waste pipe is conventionally divided at the location of fittings (5) (Fig. 9).

The implementation of the invention

The manufacture of the device according to the invention was carried out as follows.

The upper assembly piece of pipe (12) was made with such an internal diameter that a bundle of sampling tubes (4) of the sampling collector (1) passed into it.

The external and internal diameters, location and dimensions of the mounting bolt holes on the flange (9) located at the first end of the bypass connection (2) are designed so that they coincide with the corresponding parameters of the connecting flange (8) of the sampling collector (1), and external and internal diameters, location and dimensions of the mounting bolt holes on the flange (10) located at the second end of the bypass branch pipe (2), were made so that they coincided with the corresponding parameters of the connecting f lanza (16) of the lower assembly of the pipe (13). Additionally, on the flange (10) located at the second end of the bypass connection (2), mounting bolt holes were made to attach the flange (11) of the mounting connection (3) to it.

Sealing flanges provided with gaskets.

5 The lower pipe mounting section (13) was made with the size of the inner diameter, which allows fastening the flange (11) of the mounting pipe (3) to the flange (10) of the bypass pipe (2) from its (lower mounting pipe section (13)) on the inside.

The installation of the sampling collector in the vent pipe of an industrial enterprise (for example, an ore processing plant, a chemical industry, a garbage incineration plant, or any other plant where emission control is implemented) was carried out as follows.

In the body of the vent pipe, two round holes were cut out above each other in such a way that the diameter of the upper hole corresponded to the outer diameter of the upper (12) mounting pipe, and the diameter of the lower hole corresponded to the outer diameter of the lower (13) mounting pipe. Then, the upper (12) and lower (13) mounting pieces of pipes with flanges (15), (16) were pushed into the holes in the wall of the waste pipe so that from one side 20 it was possible to conduct circular welding of the walls of the pipe segments with the wall of the waste pipe, and on the other hand, they should be minimally protruding inside the discharge pipe to minimize the turbulence of the air flow as it moves inside the discharge pipe. Then the walls of the upper (12) and lower (13) mounting pieces of pipes were welded to the walls of the ventilation pipe. A suitable sealing gasket was pressed against the flange (15) of the upper 25 assembly of the pipe (12). Then, the sampling collector (1) was inserted into the upper assembly piece of pipe (12) so that the bundle of sampling tubes was placed inside the waste pipe in a horizontal position with sampling fittings (5) down to meet the air flow in the discharge pipe. The cavity inside the mounting section of the pipe (12) was filled with a heat insulator. Then, the mounting flange (14) on the sampling collector (1) was attached to the flange (15) of the upper mounting pipe segment (12) and fixed with the help of bolted joints. Flange (11) mounting the L-shaped nozzle (3) was pulled out of the vent pipe to the outside through the lower mounting section of the pipe (13) and attached to it through a sealing gasket flange (10) of the bypass pipe (2) with bolted joints. Then the flanges (9) and (10) of the bypass pipe (2) were fastened to the connecting flange (8) of the sampling collector (1) and to the flange (16) of the lower pipe assembly (13), fixed and sealed with bolts and gaskets, respectively. The surface of the bypass pipe (2) was covered with thermal insulation (18) to prevent moisture condensation in the sampling line from the air drawn from the waste pipe. By the end of the mounting L-shaped pipe (3), which is located inside the discharge pipe, the sampling pipeline was welded, which was lowered inside the discharge pipe along its wall down into the room where the stands with the equipment for monitoring gas-aerosol emissions from the discharge pipe were placed.

The above technical solution provides a representative isokinetic sampling of the controlled medium from the waste pipe. The sampling itself was carried out as follows.

The sampling pipeline, through which the gas-aerosol medium is taken from the discharge pipe using a sampling collector, was connected to gas-aerosol emission monitoring equipment. The main element of such equipment is the filter element (filter, cartridge, sorption trap, etc.) placed in the filter holder, which provides for the isolation and collection of aerosols from the air drawn from the discharge pipe. Next, the aerosols accumulated on the filter element were analyzed directly at the inspection site using automated installations (with continuous monitoring) or the filter element was removed from the filter holder of the sampling system, transferred and analyzed under laboratory conditions using laboratory equipment.

To ensure air flow through the sampling system and the filter holder, a blower was used, the inlet of which was connected to the outlet of the filter holder. The blower created a vacuum at the inlet of the filter holder with a filter element, which was transmitted throughout the whole chain of sampling elements to the suction inlets of the fittings sampling collector, due to which the air was taken from the waste pipe.

EXAMPLES OF SPECIFIC IMPLEMENTATION

The sampling collector was used as an element of the sampling system of radiation monitoring and was used at nuclear power plants with reactors of any type.

Currently, as a rule, two-block NPPs are being built, which have 4 types of ventilation pipes, differing in size.

The sampling collector used at such NPPs was made in four versions: PBAS.302637.006, PBB.302637.006-01, PBB.302637.006-02 and PBB.302637.006-03. Structurally, they differ only in the size of the sampling tubes and the internal diameters of the inlets of the fittings, which correspond to the parameters of the ventilation pipes (including the dimensions of the pipes and the average flow rates of the gas-aerosol medium discharged through the pipes in NPP operation modes) in which they must be installed.

The parameters of the vent (waste) pipes are shown in Table 1.

Table 1

The sampling collector PBAB.302637.006 is designed for continuous representative isokinetic sampling of the gas-aerosol medium from the 10UKH ventilation pipe of the nuclear power unit 1 (2). Sampling collectors PBAB.302637.006-01, PBB.302637.006-02 and PBAB.302637.006-03. designed for continuous isokinetic sampling gas-aerosol environment from general station venttrub 01 UKH, 02UKH and 03UKH, respectively.

As sampling tubes used tubes made of stainless steel, the outer diameter and wall thickness of which, respectively 18x2.5 mm. For the sampling pipeline, through which the gas-aerosol medium is transported to the measuring equipment, a pipe made of stainless steel was used, the outer diameter and wall thickness of which are, respectively, 33x2.5 mm.

The following table 2 shows examples of the overall parameters of the sampling tubes sampling collector.

table 2

In the last column of the table. 2 shows the values of the internal diameters of the inlet ports of the nozzle (5) for various versions of sampling collectors, which are designed to be placed respectively in the discharge pipes 10UKH, 01 UKH, 02UKH and 03UKH.

Given that, as can be seen from the last column of the table. 1, the relative variation of air flow 6w _BT in the discharge pipe relative to the average air flow rate of NPP operation modes is (from ± 1 to ± 7.6)%, and the relative error of maintaining the air flow rate 5W _CM through the mixing chamber (6) relative to the nominal flow rate air, is usually ± (± 5 to ± 10)%, then the relative error d of determining the value of the cross-sectional area of the inlet port of the choke (5), calculated by the formula (4), will be approximately (± 6 to ± 14) % Operating conditions for sampling collector:

- working range of air temperature: from minus 30 ° С to + 60 ° С,

- relative air humidity - up to 98% at a temperature of + 35 ° С,

- atmospheric pressure in the range from 84 to 106.7 kPa,

- resistance to sinusoidal vibration in the frequency range from

1 to 120 Hz with acceleration of 1 d.

During operation for 6 months. of the sampling collector PBAB.302637.006 on the 10UKH ventilation pipe of unit 1 of the NPP measured by radiometric installations, the volume activities of veta-aerosols and iodine-131 in the emission were from 0.02 to 0.04 Bq / m ³ and from 0.3 to 0.4 Bq / m ^3, respectively, that did not exceed the standards for maximum permissible daily emissions.

Thus, the claimed design of the sampling collector provides high representativeness when taking a gas-aerosol sample while expanding the arsenal of technical means.

Claims

CLAIM

1. Sampling collector (1), designed to select the gas-aerosol medium from the waste pipe, characterized in that it contains:

- a bundle of sampling tubes (4) of different lengths with curved ends, on which nozzles (5) are installed with sampling ends,

- mixing chamber (6) with a housing in the form of a hollow vessel, the base of which is connected to the ends of the beam of sampling tubes (4) opposite to the bent ends with fittings (5),

- a pipe segment (7), one of the ends of which is connected to the top of the mixing chamber (6), and the other end is the outlet of the sampling collector (1), and the bundle of sampling tubes (4) of the sampling collector (1) is intended to be placed inside the waste pipe by installing it through an opening in the wall of the waste pipe in a position where the axes of the inlets of the fittings (5) are parallel to the longitudinal axis of the waste pipe and are directed towards the air flow in it,

The lengths of the sampling tubes (4) are chosen so that each of the fittings (5) installed at their ends is located inside one of the zones in the form of concentric rings of equal area, into which the cross section of the waste pipe is conventionally divided at the location of the fittings (5) , and the number of which is equal to the number of sampling tubes (4) in the beam.

2. Sampling collector (1) according to claim 1, characterized in that it is intended for use as part of a radiation monitoring system for the release of radioactive aerosols, gases and iodine through a ventilation pipe at nuclear facilities.

3. Sampling collector (1) according to claim 1, characterized in that the mixing chamber (6) is made in the form of a hollow truncated cone with a taper angle of 15 ° -30 ° and coaxially connected to the pipe segment (7) by welding, and also designed for use with the mounting flange (14) installed and fixed at their joint by welding, and the base of the mixing chamber (6) is connected by welding to a bundle of sampling tubes (4), intended for use in conjunction with a round cap (17) installed at the junction of their connection.

4- Sampling collector (1) according to section 3, characterized by the fact that the longitudinal axis of the pipe section (7) and the mixing chamber (6) together with the beam of sampling pipes (4) welded to it (4) are displaced downwards relative to the axis of the plug (17) and to the axis of the mounting flange (14), the ends of the sampling tubes (4) are bent at a right angle.

5. Sampling collector (1) according to claim 1, characterized in that the bend of the ends of the sampling tubes (4) with fittings (5) is made with a radius equal to at least five internal diameters, and the sampling end of each fitting (5) is a truncated cone with a taper angle of 15-30 °, the top of which is intended to direct it towards the air flow in the waste pipe, and the distance from the ends of the sampling tubes (4), on which the nozzles (5) are installed, to the straight sections of the corresponding sampling tubes (4 ) equal to at least toe internal diameters of the sampling tube (4).

6. Sampling manifold (1) according to claim 5, characterized in that the value of the cross-sectional area of the inlet port of the choke (5) with the accuracy of the relative error d is determined by the following expression:

where: s _BX is the inlet area of the nozzle (5), cm ² ;

w is the bleed air flow rate through the sampling tube (4), cm ³ / min,

W _CM is the nominal bleed air flow through the mixing chamber (6), cm ³ / min,

p is the number of sampling tubes (4) in the beam,

W _B , · - average for the modes of operation of an industrial facility air flow in the waste pipe, cm ³ / min

d = 1, 1 (6 ² WCM ⁺ 6 ² WBT) ^1/2 .

b \ l / W is the relative dispersion of air flow in the waste pipe relative to the average air flow rate of an industrial facility,%.

7. Sampling collector (1) according to claim 1, characterized in that it contains five sampling tubes (4) in a bundle in which they are rigidly fastened together in pairs with the help of clamps (19).

8. Sampling collector (1) according to claim 7, characterized in that the end of the pipe section (7) of the sampling collector is designed to connect to the first end of the bypass branch pipe (2) located outside the waste pipe, using flanges installed on their mating ends 8) and (9), respectively, the second end of the bypass pipe (2) is designed to connect to the first end of the mounting pipe (3) located outside the waste pipe, using flanges (10) and (11) installed on their mating ends, respectively. end mounting a nozzle (3) for connection thereto by welding sampling conduit for transporting gas in an aerosol environment control equipment radioactive gas aerosol emissions from the waste pipe,

The inner diameter of the top of the hollow truncated cone of the mixing chamber (6) corresponds to the inner diameter of the pipe segment (7) and the inner diameter of the bypass branch pipe (2); the opening in the wall of the waste pipe, intended for installation through it of a bundle of sampling tubes (4), is made on the section, to which is attached the upper mounting piece of pipe (12), and the hole in the wall of the waste pipe, intended for installation through it of the mounting pipe (3), is located below the hole to accommodate a bundle of sampling tubes (4) of the sampling collector (1) and made at the site to which the lower mounting section of the pipe (13) is attached, said openings are made with diameters corresponding to the outer diameters of the said upper (12) and lower (13) mounting sections pipes, and fittings (5) are located below the hole in the wall of the waste pipe, designed to install through it a bundle of sampling tubes (4),

moreover, the upper (12) and lower (13) mounting pieces of pipes are made with flanges (15), (16), respectively, for connecting them to the mounting flange (14) of the sampling collector (1) and to the flange (10) at the end of the bypass branch pipe (2 ) respectively, as well as attached to the wall of the waste pipe by welding.

9. Sampling collector (1) of claim 8, characterized by the fact that the bypass branch pipe (2), the lower (12) and upper (13) mounting pieces of pipes are designed to cover them with thermal insulation material (18), and the bypass branch pipe (2) made U-shaped, and its bends are made with radii equal to at least five of its internal diameters; mounting pipe (3) is L-shaped, and its bend

made with a radius equal to at least five of its internal diameters.

10. Sampling collector (1) according to claim 9, characterized in that the sampling collector (1) and intended for using with it the bypass branch pipe (2) and the mounting branch pipe (3) are made of stainless steel with an electrochemically polished inner surface, and the top (12) and lower (13) pipe installation sections are made of the same steel grade as the waste pipe.