JPH0765951B2 - Gas sample dilution sampling device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a gas sample diluting and sampling apparatus that automatically dilutes a radioactive gas sample or the like and collects it in a predetermined sampling container.

[Conventional technology]

In order to measure radioactive gas generated in a nuclear power plant or the like, a gas dilution operation is performed when collecting a gas sample. Conventionally, this type of gas dilution operation is performed by the process shown in FIG. Therefore, in FIG. 4, reference numeral 10 indicates a diluting pot.
On the other hand, the gas sample supply system 12 and the dilution gas supply system 14 are connected via open / close valves 16 and 18, respectively. Further, a dilution gas discharge system 20 is led out from the dilution pot 10, and a connection portion 2 of the first opening / closing valve 22 and the sampling container 23 is provided in the discharge system 20.
4, the second opening / closing valve 26, and the vacuum pump 28 are sequentially connected and arranged. A pressure gauge 11 is provided in the dilution pot 10.

Next, a conventional gas sample dilution process having the above configuration will be described.

First, the on-off valves 16 and 18 provided in the gas sample supply system 12 and the dilution gas supply system 14 are closed, the first and second on-off valves 22 and 26 of the exhaust system 20 are opened, and the vacuum pump 28 is operated to perform dilution. Pot 1
0 and the inside of the collection container 23 is evacuated. After that, all the on-off valves are closed and the operation of the vacuum pump 28 is stopped. As a result, the insides of the dilution pot 10 and the collection container 23 are maintained in a predetermined negative pressure state.

Therefore, first open the on-off valve 16 of the gas sample supply system 12 to introduce the gas sample into the dilution pot 10 under negative pressure, and then open the on-off valve 18 of the dilution gas supply system 14 to dilute. Air or nitrogen gas (N ₂ ) is introduced under pressure into the pot 10 as a dilution gas, and the opening / closing valve 18 is closed when a predetermined pressure state is reached. This allows the dilution pot 10
Inside, the dilution of the introduced gas sample with the dilution gas is achieved at a predetermined rate. After that, by opening the first opening / closing valve 22 of the discharge system 20, the diluted gas sample held in a pressurized state in the dilution pot 10 can be easily introduced into the collection container 23.

[Problems to be Solved by the Invention]

According to the conventional dilution and sampling process of the gas sample described above, the setting of the pressure condition of the dilution pot and the opening / closing timing of the on-off valve provided in each system and its control are complicated, and the entire control system is complicated. .

Further, in the conventional device, not only the auxiliary equipment such as a vacuum pump and an aspirator is required, but also it is extremely difficult to automate all the operations in terms of work, and there is a drawback that the device becomes large in size. .

In particular, since the dilution pot is a container for a gas containing radioactivity, it is subject to legal regulation, and there is a drawback that the manufacturing cost is significantly increased because it needs to undergo official inspection such as its constituent material and welding inspection.

Therefore, an object of the present invention is to automate all the operations of the dilution step of the gas sample and the sampling operation of the diluted gas sample,
Thus, the workability is improved and a gas sample diluting and collecting device with improved safety is provided.

[Means for Solving the Problems]

The gas sample diluting and collecting apparatus according to the present invention is provided with a diluting cylinder having an externally operable piston, and is connected to one of the compartments defined by the piston of the diluting cylinder via a gas sample collecting system and a connector. The inlet pipe and the outlet pipe are connected via an on-off valve, and an air supply pipe equipped with a filter for supplying air from the outside is connected to collect the diluent gas separated in the middle part of the dilution cylinder into a required container. A sampling pipe for communicating through the on-off valve, and a branch pipe branching to the sampling pipe to the other compartment of the dilution cylinder defined by the piston. An exhaust pipe for exhausting gas to the outside is connected, and a control system for automatically performing an external operation of the piston of the dilution cylinder and an opening / closing operation of each on-off valve is provided.

In the above-mentioned gas sample diluting and collecting apparatus, the piston of the diluting cylinder is operated in a direction to expand the one chamber to depressurize the inside of the container connected to the chamber and the collecting tube, and then the gas sample is placed in the chamber. Is introduced, and a piston is operated in a direction to expand the compartment, so that a predetermined gas is introduced into the gas sample in the compartment to dilute the sample at a required magnification corresponding to the volume change.

Further, the piston of the dilution cylinder, after diluting the gas sample in the one chamber, is operated in a direction to reduce the one chamber to pressurize the inside of the chamber, thereby diluting the diluted gas in the chamber. It is configured to be introduced into the container connected to the collection tube.

[Action]

According to the gas sample dilution sampling apparatus of the present invention, the piston of the dilution cylinder is first closed with the opening / closing valves of the inlet pipe and the outlet pipe connected to the one compartment and the opening / closing valve of the sampling pipe closed. The inside of the one chamber is decompressed by operating the one chamber in an expanding direction, and then the on-off valve of the sampling pipe is opened to decompress the inside of the container connected to the sampling pipe, and then the inlet pipe. A predetermined amount of gas sample is introduced into the compartment by opening the opening / closing valve, and then the opening / closing valve of the inlet pipe is closed and the piston is operated in a direction to further expand the compartment to move to the inside of the compartment. Dilution of the gas sample can be performed by introducing a fixed amount of diluent gas.

In addition, after diluting the gas sample in a predetermined ratio in the one chamber, the inside of the chamber is pressurized by operating the piston in a direction of reducing the one chamber,
The diluted gas sample in the compartment can be introduced into a container connected to a collection tube.

By automatically performing the external operation of the piston of the dilution cylinder and the opening / closing operation of each on-off valve by the required control system, it is easy to achieve highly accurate gas sample dilution with excellent workability and safety. can do.

〔Example〕

Next, an embodiment of the gas sample diluting and collecting apparatus according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a system diagram showing an embodiment of a gas sample diluting and collecting apparatus according to the present invention. In FIG. 1, reference numerals
30 indicates a mother gas system, and a pressure reducing valve is appropriately added to this mother gas system 30.
32 is provided, and a gas sampling system 34 is branched and connected to the downstream side. Further, the gas sample collecting system 34 is provided with an external switching valve device 38 capable of switching connection with the purge gas supply system 36, and further connected to the gas dilution collecting device 42 via the connectors 40, 40. . The connectors 40, 40 can be omitted.

However, this gas dilution sampling device 42 is equipped with a dilution cylinder 44.
The dilution cylinder 44 is provided with the connectors 40, 40
An inlet tube 46 for connecting with and introducing and discharging a gas sample
And outlet pipe 48 are connected to each other via open / close valves 50 and 52, respectively. As shown in detail in FIG. 2, the dilution cylinder 44 has a piston 54 inside, and the piston 54 is appropriately vertically moved by an air cylinder 58 provided above the cylinder 44 via a piston rod 56. It is configured to be operable.
Further, in the lower compartment 60a partitioned by the piston 54 of the dilution cylinder 44, an opening 62 connected to the inlet pipe 46 is provided in the lower portion, and an opening 64 connected to the outlet pipe 48 is provided on the outer peripheral portion thereof. Each of them is provided with the opening 64.
In the same manner as described above, an opening (not shown) that connects to a dilution gas supply pipe 66 having a filter 65 for supplying air as a dilution gas from the outside is appropriately provided.

Further, the middle portion of the dilution cylinder 44 is provided with an opening 72 for connecting a collection tube 70 for collecting the diluted gas sample into the vial 68.

Furthermore, the upper compartment 60b partitioned by the piston 54 of the dilution cylinder 44 is provided with an opening 76 at the upper part for connecting to the branch pipe 74 branched from the sampling pipe 70, and for exhausting to the outside. An opening (not shown) connected to the exhaust pipe 78 is provided similarly to the opening 76.

The sampling pipe 70 and the branch pipe 74 are provided with opening / closing valves 80 and 82, respectively, and the dilution gas supply pipe 66 and the exhaust pipe 78 are provided with check valves 84 and 86, respectively. The on-off valves 80 and 82 are controlled by an electric signal system, and the on-off valves 50 and 52 and the air cylinder 58 are each controlled by an air signal system. Further, the respective on-off valves 88, 90 constituting the external switching valve 38 are also constructed so as to be controlled by the air signal system (see FIG. 1). Further, in FIG. 1, reference numeral 92 indicates a control panel equipped with a programmable controller 94 for sequentially controlling the opening / closing of each of the on-off valves by an electric signal system.

Next, regarding the operation of the gas sample diluting and collecting apparatus having the above-mentioned configuration, the diluting cylinder 44 shown in FIGS.
The operation state will be described with reference to the operation state.

Vacuum process of vial In FIG. 3 (a), the on-off valves 50 and 52 provided in the inlet pipe 46 and the outlet pipe 48 communicating with the gas sample collecting system 34 are closed and the on-off valve 80 of the collecting pipe 70 is also closed. In the branch pipe 74
The on-off valve 82 of is opened. Next, the piston 54 of the dilution cylinder 44 is lowered slightly below its middle position. As a result, the vial 68 communicating with the upper compartment 60b of the dilution cylinder 44 is inhaled. Immediately thereafter, the opening / closing valve 82 of the branch pipe 74 is closed.

Introducing Step of Gas Sample In FIG. 3 (b), after the above step, the opening / closing valves 50 and 52 provided in the inlet pipe 46 and the outlet pipe 48 communicating with the gas sample collecting system 34 are opened. At this time, the external switching valve 38 is
It is connected to the mother gas system 30 of the gas sample. In this way, the gas sample is introduced into the lower compartment 60a of the dilution cylinder 44.

Gas Sample Encapsulation Step In FIG. 3 (c), the opening / closing valves 50 and 52 provided in the inlet pipe 46 and the outlet pipe 48 communicating with the gas sample collecting system 34 are closed after the above process. This allows the dilution cylinder 44
The gas sample is enclosed in the lower compartment 60a of the.

Diluting Step In FIG. 3 (d), the piston 54 of the diluting cylinder 44 is sufficiently raised following the above step. At this time, the surplus gas in the upper compartment 60b of the dilution cylinder 44 is exhausted through the exhaust pipe 78. On the other hand, the lower compartment 60a of the dilution cylinder 44
The filter from the dilution gas supply pipe 66
Clean external air as a dilution gas is introduced via 65 to dilute the gas sample.

Step of collecting diluted gas sample into vial In FIG. 3 (e), a sampling tube 70
Open the open / close valve 80 of the piston 54 of the dilution cylinder 44.
To lower slightly. As a result, the diluted gas sample is smoothly injected into the inside of the vial 68 that has been suctioned and held in advance. In this way, the opening / closing valve 80 of the sampling tube 70 is immediately closed after the dilution gas sample is injected into the vial 68.

Gas Sample Discharging Process In FIG. 3 (f), following the above process, the piston 54 of the dilution cylinder 44 is further lowered, and the piston 54 is connected to the sampling pipe 70 provided in the middle portion of the dilution cylinder 44. When the opening 72 is closed, only the on-off valve 52 provided in the outlet pipe 48 communicating with the gas sampling system 34 is opened. As a result, the residual gas sample in the lower compartment 60a of the dilution cylinder 44 is discharged to the outlet pipe 48 as the piston 54 descends.

Purge step In FIG. 3 (g), after the above step, after switching operation to connect the external switching valve 38 to the purge gas supply system 36, the on-off valve 50 provided in the inlet pipe 46 communicating with the gas sampling system 34. Open up. As a result, the purge gas is supplied into the lower compartment 60a of the dilution cylinder 44 to clean the inside thereof. At this time, the open / close valves 80 and 82 provided in the collection pipe 70 and the branch pipe 74 for the vial are also opened.

Completion In FIG. 3 (h), the inlet pipe 46 and the outlet pipe 48 that communicate with the gas sampling system 34 after the purging process is completed.
The on-off valves 50 and 52 provided on the same are closed and the on-off valves 80 and 82 provided on the sampling system 70 and the branch pipe 74 are also closed. Then, if a new vial 68 is connected to the sampling pipe 70 and a switching operation is performed to connect the external switching valve 38 to the mother gas system 30, a series of gas sample dilution sampling work is completed, and the next gas sample dilution sampling is completed. Ready for work.

In addition, in the above-described embodiment, the dilution gas supply system has been shown to introduce air from the atmosphere, but the dilution gas supply system may be configured to supply nitrogen gas or air at atmospheric pressure or higher. . In this case, a pressure adjusting valve is provided at the inlet of the dilution cylinder 44, or a mechanism for stopping the introduction of the diluent gas by pressurizing to a constant pressure with a pressure detector (pressure transmitter, pressure switch, etc.). Thus, the dilution rate of the gas sample can be variably set.

〔The invention's effect〕

As is apparent from the above-mentioned embodiments, according to the present invention,
The gas dilution sampling device 42 is configured as a single unit, and is directly connected to the gas sampling system 34 in a detachable manner, and the control panel 92 is used to control the opening / closing of the valve and the operation of the air cylinder 58 in each of the steps 1 to 3 described above. In addition to being able to perform automatic control sequentially, it is possible to improve workability and work efficiency and safety.

In addition, since the gas dilution sampling apparatus can be configured to be extremely small, it can be installed in the gas sampling system and can be installed in an existing plant without being restricted by space. It is possible. Further, since a negative pressure line such as a vacuum pump or a negative pressure facility is not required, it can be installed in an existing plant at low cost and its workability can be remarkably improved.

Furthermore, according to the present invention, the operation time can be shortened, and the analysis of short-lived nuclides can be advantageously achieved. The effect of contributing to the improvement of the performance of the seed gas sample diluting and collecting apparatus is extremely large. .

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and it goes without saying that various design changes can be made without departing from the spirit of the present invention.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of a gas sample diluting and collecting apparatus according to the present invention, FIG. 2 is a sectional side view of a main part showing a detailed structure of a dilution cylinder shown in FIG. 1, and FIG. 3 (a). ~
(H) is an operation state explanatory view in each step of the gas sample dilution and sampling apparatus according to the present invention, and FIG. 4 is a system diagram showing a typical dilution and sampling process of a gas sample in a conventional nuclear power plant. 30 …… Mother gas system, 32 …… Pressure reducing valve 34 …… Gas sample collection system 36 …… Purge gas supply system 38 …… External switching valve device, 40 …… Connector 42 …… Gas dilution sampling device 44 …… Dilution cylinder, 46 …… Inlet pipe 48 …… Outlet pipe, 50,52 …… Open / close valve 54 …… Piston, 56 …… Piston rod 58 …… Air cylinder, 60a …… Room (lower) 60b …… Room (up), 62 …… Opening 64 …… Opening 65 …… Filter 66 …… Diluting gas supply pipe, 68 …… Vial 70 …… Collection pipe, 72 …… Opening 74 …… Branching pipe, 76 …… Opening 78 …… Exhaust pipe, 80,82 …… Open / close valve 84,86 …… Check valve, 88,90 …… Open / close valve 92 …… Control panel 94 …… Sequence controller

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kanjo Takahashi 2-1-82 Watanabe-dori, Chuo-ku, Fukuoka-shi, Fukuoka Prefecture Kyushu Electric Power Co., Inc. (72) Inventor Saetsu Arai 3-43 Ebisu, Shibuya-ku, Tokyo No. 2 inside Nikkiso Co., Ltd. (72) Inventor Takashi Koseki 3 43-2 Ebisu, Shibuya-ku, Tokyo Inside Nikkiso Co., Ltd. (56) Reference JP-A-59-104583 (JP, A) Actual Kaisho 62-126746 (JP, U)

Claims (3)

[Claims] 1. A diluting cylinder having an externally operable piston is provided, and an inlet pipe and an outlet pipe are connected to one compartment defined by the piston of the diluting cylinder via a gas sampling system through a connector. Connected via an on-off valve and connected to an air supply pipe equipped with a filter for supplying air from the outside, opening and closing a sampling pipe for sampling the diluted gas separated in the middle part of the dilution cylinder into a required container. A diluting cylinder, which is defined by the piston, is connected to the other compartment of the dilution cylinder, and a branch pipe that is branched and connected to the sampling pipe is connected to the other compartment of the diluting cylinder via an on-off valve and exhausted to the outside. And a control system for automatically performing an external operation of the piston of the dilution cylinder and an opening / closing operation of each on-off valve for the gas sample dilution sampling device. 2. A piston of a dilution cylinder is operated in a direction in which one of the compartments is expanded to decompress the inside of a container connected to the compartment and the sampling tube, and then a gas sample is introduced into the compartment. 2. The structure according to claim 1, further comprising: operating a piston in a direction in which the chamber is expanded to introduce a predetermined gas into a gas sample in the chamber to dilute the gas sample at a required magnification corresponding to a change in the volume. Gas sample dilution sampling device. 3. The piston of the dilution cylinder, after diluting the gas sample in the one compartment, is operated in a direction to reduce the one compartment to pressurize the interior of the compartment, The gas sample dilution sampling device according to claim 1, wherein the dilution gas is introduced into a container connected to the sampling tube.