RU2684601C1 - Sample collector for the representative selection of a gas-aerosol environment from a waste pipe - Google Patents

Abstract

FIELD: sampling.SUBSTANCE: invention relates to devices used as part of sampling systems, with which a representative selection of air containing aerosols is provided, from waste pipes of industrial facilities for subsequent transportation through the bypass and installation connections through the sampling pipeline to the filter unit for subsequent measurement of their physical characteristics. Sampling collector contains a bundle of sampling tubes of different lengths with curved ends, on which are installed fittings with sampling ends, a mixing chamber with a body in the form of a hollow vessel, the base of which is connected to the ends of a bundle of sampling tubes opposite to the curved ends with fittings, a pipe segment, one end of which is connected to the top of the mixing chamber, and the other end is the outlet of the sampling collector. Bundle of sampling tubes of the sampling collector is designed to be placed inside the discharge pipe by installing it through a hole in the wall of the discharge pipe in the position wherein the axis of the inlets of the nozzles are parallel to the longitudinal axis of the waste pipe and directed towards the air flow in it. Lengths of the sampling tubes are chosen so that each of the fittings installed at their ends is located inside one of the zones in the form of concentric rings of equal area, to which the cross-section of the waste pipe is conventionally divided at the location of the fittings and the number of which is equal to the number of sampling tubes in the beam.EFFECT: increasing the representativeness of the sampling of the gas-aerosol environment from the waste pipe of industrial facilities, which provides a more accurate assessment of the impact of emissions from industrial enterprises on the environmental status of the environment and improving public safety.10 cl, 9 dwg, 2 tbl, 1 ex

Description

Technical field

The present invention relates to devices used in the composition of sampling systems, with which a representative sampling of air containing aerosols from waste pipes of industrial facilities, for example, nuclear power plants, is ensured for its subsequent transportation through the bypass and assembly pipes through the sampling pipe to the filter assembly, collecting aerosols from controlled air, for subsequent measurement of their physical characteristics.

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

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

- Isokinetic sampling, i.e. equality of the flow rate of the gas-aerosol medium in the discharge pipe at the sampling point and the speed of the gas-aerosol medium in the inlet of the sampling element of the sampling collector;

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

- the aerodynamic characteristics of the sampling tubes and the mixing chamber of the sampling manifold are optimized, because the design of the sampling manifold assemblies should not introduce significant aerodynamic disturbances at the places of their placement in the discharge pipe;

- sampling units should have small geometric dimensions compared with the dimensions of the controlled discharge pipe, so as not to introduce large disturbances into the flow of air taken from the discharge pipe;

- elimination or minimization of the process of moisture condensation inside the sampling path throughout its entire length from the place of sampling from the controlled discharge pipe to the final place of sample delivery.

State of the art

The following solutions are known in the art.

Known sampling manifold containing a sampling tube with a collection chamber connected to them. The sampling collector is designed to be placed in a controlled pipeline for the purpose of taking a liquid sample from it in proportion to the flow rate of the controlled liquid in the pipeline and then transporting it and returning it through the bypass pipe back to the pipeline. The sampling tubes of the sampling manifold are made and placed in such a way that the sampling of the liquid is carried out over the entire cross section of the controlled pipeline. A bypass line containing a mixer and a fluid flow regulator is connected to an assembly line designed to discharge the sample through a dispenser connected to the analyzer. With the help of a fluid flow regulator, sampling from a controlled pipeline is isokinetic (SU 1280464, publication date 12/30/1986).

The known sampling collector does not provide representative sampling if it is used for sampling gas-aerosol media from pipelines, since it does not disclose technical means that would ensure optimal aerodynamic characteristics of the sampling elements, as a result of which a controlled gas-aerosol flow is incurred on them disturbances will be introduced into the medium flow and into the distribution of aerosols in it, thereby violating the representativeness of sampling. In addition, for such a sampling collector, the optimal conditions for the distribution of sampling tubes over the cross section of the discharge pipe have not been determined. Because Since the distribution of the velocity of the controlled gas-aerosol medium flow and the concentration of aerosols varies along the cross-section of the discharge pipe, it is important to arrange the sampling tubes along its cross-section so that the weight coefficients of the gas-aerosol medium entering the sampling chamber of the sampling collector from all the sampling tubes are equal. The fulfillment of this condition is one of the important conditions for representative sampling. Achieving the remaining conditions of representativeness of sampling is also not disclosed in the description of the well-known collector.

Thus, the main drawback of the known sampling collector is that it cannot provide a high representativeness of continuous sampling, including if it is used to take a gas-aerosol medium from an exhaust vent pipe, since of all the above conditions of representative sampling, only how only sampling isokinetic is achieved using a known collector.

Known sampling manifold, designed to be placed in a controlled pipe for sampling a gas-aerosol sample and transporting it through the bypass pipe to duplicated measuring systems. The collector is made in the form of a single sampling tube with nozzles distributed along its length. The collector is connected to a bypass pipe containing a filter unit that traps the radioactive aerosols and iodine contained in the sample, and a gas sampler into which gaseous radioactive materials enter and where their parameters are measured, as well as a regulator that controls the flow rate for isokinetic gas sampling samples. After measurement, the sample is returned back to the controlled pipe (JPS 5748634, publication date 03/20/1982).

When using the known sampling manifold for sampling a gas-aerosol medium from an exhaust vent pipe, as well as in the previous case, the optimal aerodynamic characteristics of the sampling elements are not ensured, as a result of which a controlled gas-aerosol medium is incurred onto them, disturbance is introduced into the medium flow, and, therefore, low representativeness of the sampling of the gas-aerosol medium from the discharge pipe is achieved. In addition, this design of the sampling manifold does not provide isokinetic sampling and, therefore, obtaining a representative sample when sampling from large diameter ventilation pipes (for example, from 1000 mm and above), since the nozzles 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), because when using a known collector, the rarefaction in the inlet openings 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 with the bypass pipe. Also, the design of the known sampling collector does not provide the possibility of carrying out its routine maintenance and repair work, because 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 provide a high representativeness of continuous sampling of a gas-aerosol medium from a vent pipe for the same reasons as in the previous case.

The closest analogue of the claimed invention is a sampling manifold designed for sampling hydrocarbon compounds from a controlled pipeline when used as part of a sampling device (RU 2249193, publication date 03/27/2005). The sampling manifold consists of a mixing chamber with a flange and five sampling tubes connected to it, designed to accommodate the entire section of the controlled pipeline and to continuously take part of the flow of the controlled medium through them. The sampling tubes have bent ends designed to be positioned vertically along the diameter of the pipeline being monitored. The axes of the inlet openings of the bent ends of the sampling tubes are parallel to the longitudinal axis of the controlled pipeline and are directed towards the flow and are removed from each other by a distance of 0.2 pipe diameters, while the inlet of the central tube is located on the axis of the controlled pipeline. The diameters of the sampling tubes to the center of the pipeline are reduced in accordance with a ratio of 26:20:12. The opposite ends of the intake pipes are connected to the mixing chamber, designed to connect with the inlet of the bypass pipe to transport part of the stream taken from the controlled pipeline through the sampling manifold under the influence of excessive pressure, and return the selected stream back to the controlled pipeline. The output of the bypass pipe is connected to the controlled pipeline downstream than the sampling manifold. A flow rate regulator is installed on the bypass nozzle, which ensures its adjustment through means for measuring flow parameters (means for measuring density, temperature, pressure) for the isokinetics of sampling the medium from a controlled pipeline.

The known sampling manifold can be used both for the selection of liquid and gas-aerosol media. However, in the description of its design, as well as in the description of the device known from SU 1280464 (publication date 12/30/1986), technical means were not defined to ensure the following parameters:

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

- 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 along the cross section of the discharge pipe, it is important to arrange the sampling elements along its cross section so that the weight coefficients of the samples of the gas-aerosol medium entering the sampling chamber of the sampling collector from all sampling tubes were equal. Fulfillment of this condition is also one of the important conditions for representative sampling.

In addition, the collector does not ensure the elimination or minimization of moisture condensation inside the sampling path over its entire length from the point of sampling from the controlled discharge pipe to the final delivery point of the sample, where the parameters of the controlled medium are measured, which in the case of using a device for sampling gas-aerosol samples to the deposition of aerosols on the walls of the sampling tract and, therefore, leads to incorrect measurement results.

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

Disclosure of invention

The technical problem of the present invention is the need to overcome the technical disadvantages inherent in analogues, which leads to the need to create an effective sampling collector, which would provide an increase in operational and technological characteristics with efficient 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 medium from the waste pipe of an industrial facility, which improves the accuracy of assessing the impact of industrial emissions on the state of the environment and improving public safety.

The technical result is achieved by performing a sampling manifold (1) intended for sampling a gas-aerosol medium from a waste pipe containing a bunch of sampling tubes (4) of different lengths with bent ends, on which fittings (5) with sampling ends are installed; a mixing chamber (6) with a body in the form of a hollow vessel, the base of which is connected to the ends of the bundle of sampling tubes (4), opposite the bent ends with fittings (5); a pipe segment (7), one end of which is connected to the top of the mixing chamber (6), and the second end is the outlet of the sampling manifold (1), and the bundle of sampling tubes (4) of the sampling manifold (1) is designed to be placed inside the discharge pipe by installing it through an opening in the wall of the discharge pipe in a position in which the axes of the inlet openings of the fittings (5) are parallel to the longitudinal axis of the discharge pipe and are directed towards the air flow in it, while the length of the sampling tubes (4) are selected so that each and Of the fittings (5) installed at their ends, it was located inside one of the zones in the form of concentric rings of equal area into which the cross section of the discharge pipe at the location of the fittings (5) is conditionally divided, and the number of which is equal to the number of sampling tubes (4) in the bundle .

Due to the presence of a beam in the composition of the sampling collector (1), consisting of separate sampling tubes (4), each of which is connected at one end to the mixing chamber (6), almost the same rarefaction at the ends of all fittings (5) is ensured and, accordingly, practically identical flow rates of the controlled medium at the entrance to each of the fittings (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, for example, to the design of the sampling collector known from JPS 5748634 (publication date 03/20/1982), with one sampling tube on which fittings are installed along the entire length when used in sampling there is a decrease in rarefaction at the suction ends of the fittings along the length of the sampling tube, which leads to a corresponding decrease in the flow rate of the media at the entrance to the nozzle, and the more, the further it is located from the junction of the sampling tube with the mixing chamber. If this effect is not so noticeable for small pipes of small diameter (up to 1000 mm), then for large pipes (for example, such as ventilation pipes of nuclear power plants with a diameter of 2000 to 3000 mm), the difference in speeds becomes noticeable and leads to a significant deterioration in representativeness of sampling.

Due to the execution of the ends of the sampling tubes (4) bent in such a way that the axes of the inlet openings of the nozzles (5) are directed parallel to the longitudinal axis of the discharge pipe towards the air flow in it, minimization of the disturbance of the medium flows when they run onto the nozzle and thereby increase the representativeness of the sampling .

By choosing different lengths of sampling tubes (4) so that each of the fittings installed at their ends (5) is located inside one of the zones in the form of concentric rings of equal area into which the cross section of the discharge pipe is conventionally divided into 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 discharge pipe is ensured, where all samples taken have the same weight coefficients, and further post filling in the mixing chamber (6) of the sampling collector (1) of a gas-aerosol medium from all sampling tubes (4), which leads to the most representative sampling of the cross section of the waste pipe and, as a result, increases the accuracy of assessing the impact of industrial emissions on the environment external environment and improving the safety of the population.

Thus, the claimed design of the sampling manifold provides an increase in the 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 emissions 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 a pipe segment and has external and internal diameters corresponding to the external and internal diameter of the bypass pipe, which ensures smooth, without sudden jumps, mixing of air samples coming from the sampling tubes into the mixing chamber, and its delivery to 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 the connected pipe section (7) can be designed to be used in conjunction with a mounting flange (14) mounted and fixed at their joint by welding.

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

A bundle of sampling tubes (4) connected to the base of the mixing chamber (6) can be designed to be used in conjunction with a plug (17) mounted at the junction of their connection. The plug (17) can be made round.

The longitudinal axis of the pipe segment (7) and the mixing chamber (6), together with the sample tube bundle (4) welded to it, can be shifted down with respect to the axis of the plug (17) and to the axis of the mounting flange (14), which ensures the placement of the sampling manifold inside the controlled discharge pipe so that the nozzle (5) of the sampling pipes will be located below the edge of the hole in the wall of the discharge pipe, through which the sampling manifold (1) is installed inside the discharge pipe, and the inlet openings of the nozzles are directed towards the flow air in the exhaust pipe. This solution allows at the location of the fitting (5) closest to the wall of the discharge pipe to eliminate the influence of aerodynamic disturbances arising from the passage of an air stream along the hole in the wall of the discharge pipe.

Each of the inlet sections (ends) of the sampling tubes (4) can be bent at right angles to the corresponding sampling tube (4), the bending of the ends of the sampling tubes (4) with fittings installed on them (5) can be made with a radius equal to at least five of their inner 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 a sampling pipeline to gas-aerosol emission control equipment, which increases the representativeness of the sample.

The distance from the inlet (ends) of the sampling tubes (4) on which the fittings (5) are mounted, to the straight sections of the corresponding sampling tubes (4) can be at least five internal diameters of the sampling tubes (4), which eliminates the influence of aerodynamic disturbances, arising when the air flow runs on straight sections of the sampling tubes (4), on the air flow in the places of its run on the nozzle (5) and thereby increases the representativeness of the sampling of the gas-aerosol medium by the fittings (5) of the sampling tubes (4).

The sampling end of each fitting (5) can be made in the form of a truncated cone, the top of which is designed to direct it towards the air flow in the discharge pipe. The taper angle of each nozzle (5) can be 15-30 °, the narrow part of which is directed towards the air flow in the discharge pipe, which ensures the preservation of the direction of the aerosol flow lines when the air flow on the nozzle (5) and thereby increases the representativeness of gas sampling aerosol media with fittings (5) of sampling tubes (4).

The size of the cross-sectional area of the inlet of the nozzle (5) up to a relative error δ can be determined by the following expression:

where: S _ВХ - cross-sectional area of the inlet of the fitting (5), cm ² ;

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

W _cm - nominal flow rate of sampled air through the mixing chamber (6), cm / min,

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

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

W _W - the average operating mode of an industrial facility air flow in the waste pipe, cm / min,

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

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

δ _WWt is the relative dispersion of the air flow in the waste pipe relative to the average air flow rate,% for the operation modes of an industrial facility.

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

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

The sampling tubes (4) in the bundle can be rigidly fixed in pairs with each other using brackets (19), which significantly increases the rigidity of the entire bundle of sampling tubes, resistance to vibration and aerodynamic effects of controlled air, which also further increases the representativeness of gas-aerosol sampling media with fittings (5) of sampling tubes (4).

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

The end of the pipe segment (7) can be designed to connect to the first end of the bypass pipe (2) using flanges (8) and (9) mounted 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 designed to connect a sampling pipe to it for transporting the selected medium to gas aerosol emission control equipment.

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

The mounting pipe (3) can be designed for serial connection to its second end by welding a sampling pipe, through which the gas-aerosol medium is transported to radioactive emission control equipment from the waste pipe.

The inner diameter of the apex of the hollow truncated cone of the mixing chamber (6) can correspond to the inner diameter of the bypass pipe (2).

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

The mounting pipe (3) can be designed to be placed inside the discharge 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, with its first end being connected to the second the end of the bypass pipe (2), outside the discharge pipe by installing the mounting pipe (3) through an opening in the wall of the discharge pipe, which is located below the hole for placement beam sampling tubes (4) sampling manifold (1).

The inner diameter of the upper mounting section 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 discharge pipe, designed to install a bundle of sampling tubes (4) through it, can be made in the area to which the upper mounting section of the pipe (12) is connected, and the lower hole in the wall of the discharge pipe, designed to install the mounting pipe through it (3), can be performed in the area to which the lower mounting section of the pipe (13) is connected, and said holes can be made with diameters corresponding to the outer diameters of the upper (12) and lower (13) mounting pipe segments. Due to this implementation, it is possible to carry out installation / dismantling of its individual units during routine maintenance and repair of the sampling manifold (1), as well as the possibility of laying the main part of the sampling pipe inside the discharge pipe, which minimizes the cooling of the sampled 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 are located 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 pipe, which further increases the representativeness of the sampling.

The upper (12) and lower (13) mounting pipe segments can be made with flanges (15), (16), respectively, for attaching them to the mounting flange (14) of the sampling manifold (1) and to the flange (10) at the end of the bypass pipe ( 2) respectively.

The upper (12) and lower (13) mounting pipe segments with flanges (15), (16), respectively, can be connected to the wall of the discharge pipe by welding.

Bypass pipe (2), lower (12) and upper (13) mounting pipe segments can be designed to cover them with heat-insulating material (18).

Bypass pipe (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 inner diameters. Mounting pipe (3) can be made L-shaped. The bend of the mounting pipe (3) can be performed with a radius equal to at least five of its inner diameters. The implementation of the bypass U-shaped pipe and the mounting L-shaped pipe with the above-mentioned bends minimizes the inertial deposition of aerosols of the gas-aerosol sample during transportation along the bends and thus also minimizes the loss of radioactive aerosols and iodine during transportation to gas-aerosol emission control equipment.

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

When the bypass pipe (2), which is small and U-shaped, is located outside the discharge pipe and coated with heat-insulating material, it is possible to lay a sampling pipe inside the controlled discharge pipe, which allows for a minimum difference between the temperature of the sampled air and the temperature of the controlled air inside the discharge pipes along the entire length of the sampling pipeline. This prevents the condensation of moisture contained in the controlled air inside the sampling path along its entire length from the point of sampling from the controlled vent pipe to the final delivery location of the sample (gas aerosol emission control equipment), which also minimizes the loss of radioactive aerosols and iodine.

The sampling manifold (1), the bypass pipe (2) and the mounting pipe (3) can be made of stainless steel, and the upper (12) and lower (13) pipe sections can be made of the same steel grade as the discharge pipe and the sampling manifold (1), the bypass pipe (2) and the mounting 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 transportation to the equipment Hovhan gas aerosol emissions control and, therefore, increases the representation of sampling.

Description of drawings

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

In FIG. 1 - sampling manifold a) side view, b) top view,

in FIG. 2 - section of the fitting,

in FIG. 3 - bypass pipe with a flange for attaching a pipe segment (7) and a flange for attaching a mounting pipe (3),

in FIG. 4 - mounting pipe with flange,

in FIG. 5 - the upper mounting section of the pipe with a flange,

in FIG. 6 - lower mounting pipe section with a flange,

in FIG. 7 is a sectional view of the bracket connecting the sampling tubes,

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

in FIG. 9 is a diagram explaining a conditional partition of the cross section of the ventilation pipe into five zones in the form of concentric rings of equal area, where: S ₁ = S ₂ = S ₃ = S ₄ = S ₅ .

The positions in the figures indicated:

1 - sampling manifold,

2 - bypass pipe,

3 - mounting pipe

4 - sampling tubes,

5 - fitting

6 - mixing chamber,

7 - pipe section,

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

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

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

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

12 - upper mounting pipe section,

13 - lower mounting pipe

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

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

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

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

18 - thermal insulation,

19 - bracket.

The sampling collector (1) contains a bundle consisting of five sampling tubes (4) interconnected by brackets (19). The tubes in the bundle are made of different lengths with ends bent at right angles. At the bent ends of the sampling tubes (4), fittings (5) are installed with sampling ends. A bundle of sampling tubes (4) is connected in series with the mixing chamber (6) and with the end with a pipe segment (7), at the junction of the connection, a round plug (17) is installed. The opposite end of the pipe segment (7) is the outlet of the sampling manifold (1) and contains a flange (8) for connection with the end of the bypass pipe (2). At the junction of the connection of the mixing chamber (6) and the pipe section (7), a mounting flange (14) is installed to connect the upper (12) pipe mounting section (Fig. 1).

The sampling end of the fitting (5) mounted on the end of the sampling tube (4) is made in the form of a truncated cone, the top of which is designed to direct it towards the air flow in the discharge pipe (Fig. 2).

The sampling manifold (1) is connected in series with the U-shaped bypass pipe (2) and with the L-shaped mounting pipe (3).

The first end of the bypass pipe (2) is connected to the mounting pipe (3) by means of flanges (8) and (9) mounted 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) using flanges (10) and (11) installed on their mating ends, respectively (Fig. 4).

The outlet of the sampling manifold (1) is designed to be placed inside the upper mounting pipe segment (12) with a flange (15) located on the pipe wall section with the upper hole (Fig. 5).

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

Sample tubes (4) are interconnected by brackets (19) in pairs (Fig. 7).

The sampling device assembly comprises a sampling manifold (1) partially placed inside the discharge pipe through an upper hole in its wall, a bypass pipe (2) located outside the discharge pipe, and a mounting pipe (3), the first end of which is connected to the end of the bypass pipe ( 2) outside the discharge pipe, and the second end is placed inside the discharge pipe through the lower hole in its wall and connected to a sampling pipe through which the gas-aerosol medium is transported to the monitoring equipment oaktivnyh emissions.

On the wall of the discharge pipe one above the other in areas where the upper and lower holes are made, the upper (12) and lower (13) mounting pipe segments are fixed. A bundle of sampling tubes (4) of the sampling manifold (1) is placed inside the discharge pipe by installing it through the upper hole. The first end of the mounting pipe (3), connected to the end of the bypass pipe (2), is placed inside the discharge pipe by installing it through the lower hole. The upper (12) and lower (13) mounting pipe segments contain flanges (15), (16) respectively, attached to the mounting flange (14) of the sampling manifold (1) and to the flange (10) at the end of the bypass pipe (2), respectively. The longitudinal axis of the pipe segment (7) and the mixing chamber (6) together with the bundle of sampling tubes (4) welded to it is shifted 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 upper hole in the wall of the discharge pipe.

The mounting pipe (3) is designed for sequentially connecting its second end by welding to a sampling pipe, through which the gas-aerosol medium is transported to radioactive emission control equipment from the waste pipe.

Bypass pipe (2), lower (12) and upper (13) pipe sections are coated with heat-insulating material (18).

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

The conditional zones are concentric rings of equal area S ₁ = S ₂ = S ₃ = S ₄ = S ₅ into which the cross section of the waste pipe is conventionally divided into the place of the 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 mounting section of the pipe (12) was made with such an inner diameter so that a beam of sampling tubes (4) of the sampling collector (1) passed through it.

The outer and inner diameters, location and dimensions of the mounting holes for the bolts on the flange (9) located on the first end of the bypass pipe (2) were made so that they coincided with the corresponding parameters of the connecting flange (8) of the sampling manifold (1), and the outer and inner diameters, the location and dimensions of the mounting holes for the bolts on the flange (10) located on the second end of the bypass pipe (2) were made so that they coincided with the corresponding parameters of the connecting flange (16) of the lower pipe mounting section (13).

Additionally, on the flange (10) located at the second end of the bypass pipe (2), mounting holes were made for the bolts to connect the flange (11) of the mounting pipe (3) to it.

Flange sealing was provided with gaskets.

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

Installation of the sampling manifold in the ventilating pipe of an industrial enterprise (for example, an ore processing plant, a chemical enterprise, a waste incinerator, or any other plant where emission control is implemented) was carried out as follows.

In the body of the ventilation pipe, two round holes were cut out one above the other so that the diameter of the upper hole corresponded to the outer diameter of the upper (12) mounting section of the pipe, and the diameter of the lower hole corresponded to the external diameter of the lower (13) mounting section of the pipe. Then, the upper (12) and lower (13) mounting pipe segments with flanges (15), (16) were pushed into the holes in the wall of the discharge pipe so that on one side it was possible to conduct circular welding of the walls of the pipe segments with the wall of the discharge pipe, and with on the other hand, so that they protrude minimally inside the discharge pipe to minimize swirls of the air flow as it moves inside the discharge pipe. Then the walls of the upper (12) and lower (13) mounting pipe segments were welded to the walls of the vent pipe. An appropriate sealing gasket was pressed against the flange (15) of the upper mounting section of the pipe (12). Then, a sampling manifold (1) was inserted into the upper mounting section of the pipe (12) so that the bundle of sampling pipes was placed inside the discharge pipe in a horizontal position with the sampling nozzles (5) down to meet the air flow in the discharge pipe. The cavity inside the pipe mounting section (12) was filled with a heat insulator. Then, the mounting flange (14) on the sampling manifold (1) was connected to the flange (15) of the upper pipe mounting section (12) and fixed using bolted connections. The flange (11) of the mounting branch pipe (3) of the L-shaped form was pulled out through the lower mounting section of the pipe (13) from the ventilation pipe and fastened to it through the sealing gasket by the flange (10) of the bypass pipe (2) using bolted connections. Then, the flanges (9) and (10) of the bypass pipe (2) were attached to the connecting flange (8) of the sampling manifold (1) and to the flange (16) of the lower pipe mounting section (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 taken from the discharge pipe. At the end of the mounting L-shaped pipe (3), which is inside the discharge pipe, a sampling pipe was welded, which was lowered inside the discharge pipe along its wall down to the room where the stands with gas and aerosol emission control equipment from the discharge pipe were placed.

The above technical solution provides representative isokinetic sampling of a controlled environment from waste pipes. Sampling itself was carried out as follows.

A sampling pipeline through which a gas-aerosol medium is taken from a discharge pipe using a sampling manifold is connected to gas-aerosol emission control equipment. The main element of such equipment is a filter element (filter, cartridge, sorption trap, etc.), located in the filter holder, with the help of which the extraction and collection of aerosols from the air taken from the waste pipe is ensured. Next, the aerosols accumulated on the filter element were analyzed directly at the control site using automated installations (with continuous monitoring) or the filter element was removed from the filter holder of the sampling system, transferred and analyzed in laboratory conditions using laboratory equipment.

To ensure air flow through the sampling system and the filter holder, a blower was used, the input of which was connected to the output of the filter holder. The blower created a vacuum at the inlet of the filter holder with a filter element, which was transmitted along the entire chain of sampling elements to the suction inlets of the nozzles of the sampling manifold, due to which air was taken from the discharge pipe.

Specific implementation examples

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

At present, as a rule, two-unit nuclear power plants are built, which have 4 types of ventilation pipes of different sizes.

The sampling collector used at such nuclear power plants was performed in four versions: ПБАВ.302637.006, ПБАВ.302637.006-01, ПБАВ.302637.006-02 and ПБАВ.302637.006-03. Structurally, they differ only in the sizes of the sampling tubes and the internal diameters of the inlet openings of the fittings, which correspond to the parameters of the ventilation pipes (including the pipe sizes and the average discharge rates of gas-aerosol media discharged through the pipes) in which they should be installed.

The parameters of the ventilation (exhaust) pipes are shown in table 1.

The sampling collector PBAV.302637.006 is designed for continuous representative isokinetic sampling of the gas-aerosol medium from the ventilation pipe 10UKH of Unit 1 (2) of the NPP. Sample collectors PBAV.302637.006-01, PBAV.302637.006-02 and PBAV.302637.006-03. are intended for continuous isokinetic sampling of a gas-aerosol medium from station-wide vent pipes 01UKH, 02UKH and 03UKH, respectively.

As sampling tubes, tubes made of stainless steel were used, the outer diameter and wall thickness of which were 18 × 2.5 mm, respectively. 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 33 × 2.5 mm, respectively.

Table 2 below shows examples of the overall parameters of the sampling tubes of the sampling manifold.

The last column of Table 2 shows the values of the internal diameters of the inlet openings of the nozzle (5), for various designs of sampling collectors, which are designed to be placed in the waste pipes 10UKH, 01UKH, 02UKH and 03UKH, respectively.

Given that, as can be seen from the last column of the table. 1, the relative dispersion of the air flow rate δ _W in the discharge pipe relative to the average air flow rate for NPP operation modes is (± 1 to ± 7.6)%, and the relative error in maintaining the air flow rate δ _{W cm} through the mixing chamber (6) relative to the nominal flow rate of air is usually ± (from ± 5 to ± 10)%, then the relative error δ of determining the size of the cross-sectional area of the inlet of the nozzle (5), calculated by formula (4), will be approximately (from ± 6 to ± 14) %

Sample Collector Operating Conditions:

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

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

- 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 an acceleration of 1 g.

During operation for 6 months. of the sample collector ПБАВ.302637.006 on the vent tube 10UKH of unit 1 of the NPP, the volumetric activity of the veta aerosols and iodine-131 measured by radiometric devices ranged from 0.02 to 0.04 Bq / m ³ and from 0.3 to 0.4 Bq / m ^3, respectively, which did not exceed the standards for maximum permissible daily emissions.

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

Claims (30)

1. A sampling manifold (1), designed for sampling a gas-aerosol medium from a discharge pipe, characterized in that it contains: - a bundle of sampling tubes (4) of different lengths with bent ends, on which the fittings (5) with sampling ends are installed, - a mixing chamber (6) with a body in the form of a hollow vessel, the base of which is connected to the ends of the bundle of sampling tubes (4), opposite the bent ends with fittings (5), - a segment of pipe (7), one of the ends of which is connected to the top of the mixing chamber (6), and the second end is the outlet of the sampling collector (1), moreover, the bundle of sampling tubes (4) of the sampling manifold (1) is designed to be placed inside the discharge pipe by installing it through an opening in the wall of the discharge pipe in a position in which the axes of the inlet openings of the nozzles (5) are parallel to the longitudinal axis of the discharge pipe and are directed towards the air flow in her, the length of the sampling tubes (4) is chosen so that each of the fittings installed at their ends (5) is located inside one of the zones in the form of concentric rings of equal area into which the cross section of the discharge pipe is conventionally divided into the location of the fittings (5) and the number of which is equal to the number of sampling tubes (4) in the beam. 2. A 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 vent pipe at nuclear facilities. 3. A sampling manifold (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 is coaxially connected to a pipe segment (7) by welding, and is also intended for use in conjunction with a mounting flange (14) mounted and fixed at their junction by welding, and the base of the mixing chamber (6) is connected by welding with a bundle of sampling tubes (4) intended for use with a round plug (17) mounted on the junction them with togetherness. 4. The sampling manifold (1) according to claim 3, characterized in that the longitudinal axis of the pipe segment (7) and the mixing chamber (6) together with the bundle of sampling tubes (4) welded to it are shifted downward with respect 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. The sampling manifold (1) according to claim 1, characterized in that the bending 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 made in the shape of a truncated cone with a taper angle of 15-30 °, the top of which is designed to direct it towards the air flow in the discharge pipe, and the distance from the ends of the sampling tubes (4), on which the fittings (5) are mounted, to the straight sections of the corresponding sampling tubes (4 ) is at least five internal diameters of the sampling tube (4). 6. The sampling collector (1) according to claim 5, characterized in that the cross-sectional area of the inlet of the nozzle (5), up to a relative error of 5, is determined by the following expression:

where s _I - the inlet area of the fitting (5), cm ² ; w is the flow rate of sampled air through the sampling tube (4), cm ³ / min,

W _cm - nominal flow rate of sampled air through the mixing chamber (6), cm ³ / min, n is the number of sampling tubes (4) in the beam, V is the linear air velocity along the internal section of the discharge pipe at the location of the fittings (5) of the sampling tubes (4), cm / min,

W _W - the average mode of operation of an industrial facility air flow in the waste pipe, cm ³ / min, S is the internal cross-sectional area of the pipe at the location of the fittings (5) of the sampling tubes (4), cm ² ,

δ _Wcm - the relative error of maintaining the air flow through the mixing chamber (6) relative to the nominal air flow,%, δ _WWt is the relative dispersion of the air flow in the waste pipe relative to the average air flow rate,% for the operation modes of an industrial facility. 7. The sampling collector (1) according to claim 1, characterized in that it contains five sampling tubes (4) in a bundle in which they are coupled rigidly fastened to each other using brackets (19). 8. The sampling manifold (1) according to claim 7, characterized in that the end of the pipe segment (7) of the sampling manifold is designed to connect to the first end of the bypass pipe (2) located outside the discharge pipe using flanges installed on their mating ends ( 8) and (9) respectively, the second end of the bypass pipe (2) is designed to connect with the first end of the mounting pipe (3) located outside the discharge pipe, using the flanges (10) and (11) mounted on their mating ends, respectively, the second end mounting th branch pipe (3) is designed to be connected to it by welding a sampling pipe for transporting a gas-aerosol medium to the equipment for monitoring radioactive gas-aerosol emissions from a waste pipe, the inner diameter of the apex 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 pipe (2), the hole in the wall of the discharge pipe, designed to install a bundle of sampling tubes (4) through it, is made on the site, to which the upper mounting section of the pipe is connected (12), and the hole in the wall of the discharge pipe, intended for installation through it of the mounting pipe (3), is located below the hole for accommodating the sample tube bundle (4) selected collector (1) and is made in the area to which the lower pipe mounting section (13) is attached, said holes are made with diameters corresponding to the outer diameters of the upper (12) and lower (13) pipe pipe sections, and the nozzle (5) are located below the hole in the wall of the discharge pipe, designed to install through it a bundle of sampling tubes (4), moreover, the upper (12) and lower (13) mounting pipe segments are made with flanges (15), (16), respectively, for attaching them to the mounting flange (14) of the sampling manifold (1) and to the flange (10) at the end of the bypass pipe (2 ) respectively, as well as attached to the wall of the discharge pipe by welding. 9. A sampling manifold (1) according to claim 8, characterized in that the bypass pipe (2), the lower (12) and upper (13) pipe pieces are designed to be coated with heat-insulating material (18), and the bypass pipe (2) made U-shaped, and its bends are made with radii equal to at least five of its inner diameters; the mounting pipe (3) is made L-shaped, and its bend is made with a radius equal to at least five of its inner diameters. 10. The sampling manifold (1) according to claim 9, characterized in that the sampling manifold (1) and the bypass pipe (2) and mounting pipe (3) intended for use with it are made of stainless steel with an electrochemically polished inner surface, and the upper (12) and the bottom (13) mounting pipe sections are made of the same steel grade as the waste pipe.

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