Flow measuring equipment and tracer gas sampling device thereof

Abstract

The utility model relates to flow measuring equipment and a tracer gas sampling device thereof, and the sampling device is arranged at the downstream of a tracer gas injection point of a flow pipeline to be measured. The sampling device comprises a plurality of gas extraction mechanisms which are mechanically connected with the to-be-measured flow pipeline so as to synchronously extract sample gas formed by mixing tracer gas and gas conveyed by the pipeline; the plurality of gas collecting pieces are mechanically connected with the plurality of gas extraction mechanisms one by one and are used for collecting the sample gas; and the control module is electrically connected with the plurality of air exhaust mechanisms and is used for controlling the plurality of air exhaust mechanisms to work. According to the utility model, the problem of poor flow measurement accuracy caused by gas concentration deviation at different sampling point positions and obvious time difference of sampling time of different sampling points is solved, the credibility of sample gas is improved, and the flow measurement accuracy is further effectively improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to gas flow measurement technical field especially relates to flow measurement equipment and its tracer gas sampling device. BACKGROUND

[0002] In the field of heating ventilation and air conditioning, it is often necessary to measure the air flow in the pipeline, and the commonly used methods include pitot tube flow method and hot-wire anemometer measurement method. These methods all require stable airflow conditions, that is, the airflow at the measurement point is stable and has no turbulence, which requires a long and straight pipeline before and after the measurement point. However, due to the reasons such as factory space and equipment arrangement, it is difficult to find a suitable measurement point. Since the tracer gas flow method is more suitable for places with very low flow rate or lack of suitable measurement positions, nuclear power plants usually use the tracer gas flow method to realize air flow measurement. Although the tracer gas flow method is based on the principle of mass conservation and is independent of airflow conditions, it does not require measurement of the area of the air duct or flow calibration, but it requires that the injected tracer gas be fully mixed with the airflow in the pipeline to obtain better measurement results. However, the distribution of tracer gas concentration in the cross-sectional space of the pipeline is usually uneven, resulting in deviations in gas concentration at different sampling point positions, and there is also a significant time difference in sampling time at different sampling points, thus leading to poor accuracy of flow measurement. SUMMARY

[0003] The technical problem to be solved by the utility model is to provide a flow measurement equipment and its tracer gas sampling device.

[0004] The utility model adopts the technical scheme that a tracer gas sampling device is constructed, which is arranged downstream of a tracer gas injection point of a to-be-measured flow pipeline, and the tracer gas sampling device comprises:

[0005] a plurality of air extraction mechanisms for mechanically connecting the to-be-measured flow pipeline to synchronously extract sample gas mixed with the tracer gas and the gas transported by the pipeline;

[0006] a plurality of gas collection pieces mechanically connected one-to-one with the plurality of air extraction mechanisms for collecting the sample gas; and

[0007] a control module electrically connected with the plurality of air extraction mechanisms for controlling the operation of the plurality of air extraction mechanisms.

[0008] Preferably, each air extraction mechanism comprises a vacuum pump and a three-way valve;

[0009] The air inlet end of the vacuum pump is used for mechanically connecting the to-be-measured flow pipeline, and the vacuum pump is electrically connected with the control module;

[0010] The outlet end of the vacuum pump is mechanically connected with the first valve port of the three-way valve, the second valve port of the three-way valve is mechanically connected with the gas collecting member, the third valve port of the three-way valve is communicated with the outside, and the three-way valve is electrically connected with the control module.

[0011] Preferably, the control module comprises a control unit, a plurality of first switch units and a plurality of second switch units.

[0012] Each first switch unit is electrically connected with each vacuum pump in one-to-one correspondence, and the control unit is electrically connected with each first switch unit to control the vacuum pumps to start or stop simultaneously.

[0013] Each second switch unit is electrically connected with each three-way valve in one-to-one correspondence, and the control unit is electrically connected with each second switch unit to control the first valve port and the second valve port of the three-way valve to be communicated simultaneously or the first valve port and the third valve port to be communicated simultaneously.

[0014] Preferably, each first switch unit comprises a first relay, the exciting coil of each first relay is electrically connected with the control unit, and the normally open contact loop of each first relay is electrically connected between the power supply end of each vacuum pump and a power supply in one-to-one correspondence.

[0015] Each second switch unit comprises a second relay, the exciting coil of each second relay is electrically connected with the control unit, and the normally open contact loop of each second relay is electrically connected between the power supply end of each three-way valve and a power supply in one-to-one correspondence.

[0016] Preferably, the control unit comprises a PLC controller, and the PLC controller is electrically connected with the exciting coil of each first relay and the exciting coil of each second relay, respectively.

[0017] Preferably, the control module further comprises a first operation unit and a second operation unit.

[0018] The first operation unit is electrically connected with the control unit, and the first operation unit is used for controlling the vacuum pumps to start or stop simultaneously according to operation.

[0019] The second operation unit is electrically connected with the control unit, and the second operation unit is used for controlling the first valve port and the second valve port of the three-way valve to be communicated simultaneously or the first valve port and the third valve port to be communicated simultaneously according to operation.

[0020] Preferably, each gas collecting member comprises a sealed bag.

[0021] Preferably, the number of the gas collecting members and the number of the vacuum pumps are both 6.

[0022] The utility model further constructs a kind of flow measuring equipment, including the tracer gas sampling device described above.

[0023] Preferably, the flow measuring equipment further comprises:

[0024] a gas analyzer for analyzing the sample gas concentration in each gas collection piece; and

[0025] an analysis module for determining the gas flow in the flow pipeline to be measured according to the concentration of each sample gas.

[0026] The utility model has the following beneficial effects: a tracer gas sampling device is provided, which simultaneously collects sample gas at multiple sampling points in the flow pipeline to be measured, and provides sample gas with higher reliability for the gas analyzer, solves the problem of poor flow measurement accuracy caused by the concentration deviation of gas at different sampling points and the significant time difference in sampling time at different sampling points, improves the reliability of sample gas, and effectively improves the accuracy of flow measurement. BRIEF DESCRIPTION OF DRAWINGS

[0027] The utility model will be further described below with reference to the drawings and examples, and the drawings are as follows:

[0028] Figure 1 is the structural schematic diagram of tracer gas sampling device in an embodiment of the utility model;

[0029] Figure 2 is the sampling point position distribution diagram on a certain cross section in an embodiment of the utility model;

[0030] Figure 3 is the valve port communication schematic diagram when three-way valve is powered on in an embodiment of the utility model;

[0031] Figure 4 is the valve port communication schematic diagram when three-way valve is powered off in an embodiment of the utility model;

[0032] Figure 5 is the circuit structure block diagram of control module in an embodiment of the utility model. DETAILED DESCRIPTION

[0033] In order to have more clear understanding on the technical features, objects and effects of the utility model, the specific implementation mode of the utility model will be described in detail with reference to the drawings.

[0034] In the following description, it needs to be understood that the directions or position relations indicated by "front", "back", "upper", "lower", "left", "right", "vertical", "horizontal", "vertical", "horizontal", "top", "bottom", "inner", "outer", "head", "tail" and the like are based on the directions or position relations shown in the drawings, constructed and operated in a particular direction, only for the convenience of describing the technical solutions, and cannot be understood as indicating that the devices or elements indicated must have a particular direction, therefore, it cannot be understood as a limitation on the practical new type.

[0035] Figure 1 is a structural schematic view of a tracer gas sampling device in an embodiment of the practical new type, the tracer gas sampling device is arranged downstream of a tracer gas injection point of a to-be-measured flow pipeline 40 (the to-be-measured flow pipeline 40 refers to a pipeline whose gas flow in the pipeline needs to be measured), so as to simultaneously collect sample gas of multiple sampling points on the same cross section of the to-be-measured flow pipeline 40, and provide sample with higher credibility for a gas analyzer, thereby solving the problem of poor flow measurement accuracy caused by gas concentration deviation of different sampling point positions and obvious time difference of sampling time of different sampling points.

[0036] Please refer to Figure 1 and Figure 5 , the tracer gas sampling device can include a control module 3, multiple air extraction mechanisms 1 and multiple gas collection pieces 2.

[0037] The multiple air extraction mechanisms 1 are respectively used for mechanically connecting the to-be-measured flow pipeline 40, so as to synchronously extract sample gas after tracer gas is mixed with gas delivered by the pipeline. Specifically, each air extraction mechanism 1 can be mechanically connected to a pipeline cross section at a downstream of the tracer gas injection point of the to-be-measured flow pipeline 40, and the sampling points of each air extraction mechanism 1 are preferably uniformly distributed on the cross section. For example, when the number of air extraction mechanisms 1 is 9, the distribution of the sampling points can refer to Figure 2 It can be understood that the pipeline cross section can be first equally divided into 9 equal parts to obtain 9 sub-cross section regions, and then the center points of each sub-cross section region are determined as sampling points, so as to obtain the sampling points C1 to C9 as shown in Figure 2 When the number of air extraction mechanisms 1 is other, the sampling point positions can also be determined by referring to the above method.

[0038] The multiple gas collection pieces 2 are one-to-one mechanically connected with the multiple air extraction mechanisms 1, and each gas collection piece 2 is used for collecting sample gas on the corresponding sampling point.

[0039] The control module 3 is electrically connected with the plurality of air extraction mechanisms 1 respectively, and the control module 3 is configured to control the plurality of air extraction mechanisms 1 to perform simultaneous air extraction. Specifically, the control module 3 can control the air extraction mechanisms 1 to perform air extraction, so as to extract sample gas at each sampling point on the cross section of the pipeline into the corresponding gas collection member 2, and complete the sampling work. Further, since the control module 3 in the embodiment controls the air extraction mechanisms 1 to perform air extraction at the same time, the sample gas collected by the gas collection members 2 is extracted at the same time and on the same cross section as much as possible, so as to eliminate the time difference problem of sampling at different sampling points, and further improve the credibility of the sample gas, and play a positive role in improving the accuracy of flow measurement.

[0040] In one embodiment, as shown in Figure 1 each air extraction mechanism 1 can include a vacuum pump 11 and a three-way valve 12.

[0041] The air inlet end of the vacuum pump 11 is configured to be mechanically connected with the pipeline 40 to be measured, and the vacuum pump 11 is electrically connected with the control module 3. Specifically, the air inlet end of each vacuum pump 11 can be connected to the corresponding sampling point in the pipeline 40 to be measured through a pipeline, and the control module 3 can control the vacuum pumps 11 to start or stop. When the vacuum pump 11 is started, sample gas is extracted into the corresponding gas collection member 2. The three-way valve 12 can be an existing three-way electromagnetic valve.

[0042] The air outlet end of the vacuum pump 11 is mechanically connected with the first valve port C of the three-way valve 12, the second valve port A of the three-way valve 12 is mechanically connected with the gas collection member 2, the third valve port B of the three-way valve 12 is connected with the outside, and the three-way valve 12 is electrically connected with the control module 3. Specifically, the control module 3 can control whether the three-way valve 12 is powered on. When the three-way valve 12 is powered on, as shown in Figure 3 the first valve port C of the three-way valve 12 is connected with the second valve port A, and the first valve port C is disconnected with the third valve port B. When the three-way valve 12 is powered off, as shown in Figure 4 the first valve port C of the three-way valve 12 is disconnected with the second valve port A, and the first valve port C is connected with the third valve port B. The vacuum pump 11 can be an existing vacuum pump.

[0043] It should be noted that, since the vacuum pump 11 and the three-way valve 12 are connected to the pipeline of the flow pipe 40 to be measured, before the tracer gas is injected, the pipeline between the vacuum pump 11, the three-way valve 12 and the flow pipe 40 to be measured is filled with the gas originally transported by the flow pipe 40 to be measured, which is not mixed with the tracer gas (referred to as unmixed gas) or the gas remaining from the previous sampling. If these gases are not discharged and directly injected into the gas collection device 2 during the current sampling, the credibility of the sample gas will be reduced. The third valve port B is used to discharge the residual gas or unmixed gas in the pipeline, so as to ensure that the gas extracted during the current sampling is the gas mixed with the tracer gas injected during the current sampling and the gas currently transported by the flow pipe 40 to be measured. The specific implementation method is that, after the vacuum pumps 11 are started at the same time, the control module 3 will start timing (using the existing algorithm), and when the trigger time is reached, the control module 3 controls the three-way valves 12 to be energized at the same time. In this way, the unmixed gas and the residual gas can be discharged before sampling, thereby improving the credibility of the sample gas.

[0044] In one embodiment, as shown in FIG. 1, Figure 5 The control module 3 can include a control unit 31, a plurality of first switch units 32 and a plurality of second switch units 33.

[0045] Each first switch unit 32 is electrically connected to each vacuum pump 11 one by one, and the control unit 31 is electrically connected to each first switch unit 32 to control the vacuum pumps 11 to start or stop at the same time. Specifically, each first switch unit 32 can include a first relay. The magnet coil of each first relay is electrically connected to the control unit 31, and the normally open contact loop of each first relay is electrically connected between the power supply end of each vacuum pump 11 and the power supply one by one. It can be understood that the control unit 31 can control the vacuum pumps 11 to start or stop by controlling whether the first relay is magnetized. Of course, the first relay can also be replaced by other switching devices, such as triodes, MOS tubes and thyristors.

[0046] Each second switch unit 33 is electrically connected to each three-way valve 12 one by one, and the control unit 31 is electrically connected to each second switch unit 33 to control the first valve port and the second valve port of each three-way valve 12 to be connected at the same time or the first valve port and the third valve port to be connected at the same time. Specifically, each second switch unit 33 can include a second relay, and the magnet coil of each second relay is electrically connected to the control unit 31. The normally open contact loop of each second relay is electrically connected between the power supply end of each three-way valve 12 and the power supply one by one. It can be understood that the control unit 31 can control whether the three-way valve 12 is energized by controlling whether the second relay is magnetized. Of course, the second relay can also be replaced by other switching devices, such as triodes, MOS tubes and thyristors.

[0047] In one embodiment, the control unit 31 can comprise an existing PLC controller, which is electrically connected with the excitation coils of the first relays and the excitation coils of the second relays respectively, and in turn controls whether the first relays and the second relays are excited. It can be understood that the control unit 31 can send the same operation signal to all the first relays at the same time, so as to realize simultaneous control of the vacuum pumps 11 to start or stop (the time difference of the execution actions of the start or stop of each vacuum pump 11 is generally within 0.1 seconds), and similarly, when the control unit 31 sends the same control signal to all the second relays at the same time, the first valve port C and the second valve port A of the three-way valve 12 can be simultaneously communicated or the first valve port A and the third valve port B can be simultaneously communicated (the time difference of the execution actions of the three-way valve 12 is also generally within 0.1 seconds).

[0048] In one embodiment, as shown in FIG. 4, the control module can further comprise a first operation unit 34 and a second operation unit 35. Figure 5

[0049] The first operation unit 34 is electrically connected with the control unit 31, and the first operation unit 34 is used for inputting a first operation signal capable of controlling the vacuum pumps 11 to start or stop at the same time to the control unit 31 according to the operation of the staff on the first operation unit 34, that is, the operation of the first operation unit 34 can realize the control of the vacuum pumps 11 to start or stop at the same time. The first operation unit 34 can comprise an existing button or operation switch.

[0050] The second operation unit 35 is electrically connected with the control unit 31, and the second operation unit 35 is used for inputting a second operation signal capable of controlling the first valve port C and the second valve port A of the three-way valve 12 to be communicated at the same time or the first valve port C and the third valve port B to be communicated at the same time to the control unit 31 according to the operation of the staff on the second operation unit 35, that is, the operation of the second operation unit 35 can realize the control of the first valve port C and the second valve port A of the three-way valve 12 to be communicated at the same time or the first valve port C and the third valve port B to be communicated at the same time. The second operation unit 35 can comprise an existing button or operation switch.

[0051] In one embodiment, each gas collecting piece 2 can comprise a sealed bag.

[0052] Optionally, the number of the gas extraction mechanisms 1 and the gas collecting pieces 2 can be 6.

[0053] The utility model further provides a flow measuring device, including the tracer gas sampling device provided by the utility model embodiment.

[0054] In one embodiment, the flow measuring device can further comprise a gas analyzer and an analysis module.

[0055] ​The gas analyzer is used for analyzing the sample gas concentration in each gas collecting part 2. Specifically, the gas analyzer can be an existing gas analysis device or module, which can analyze the tracer gas concentration (i.e. the sample gas concentration) in the sample gas.

[0056] The analysis module is used for determining the gas flow in the flow pipe to be measured according to the concentration of each sample gas. Specifically, the analysis module can first calculate the average value of the concentration of each sample gas by using an existing algorithm, and then calculate the gas flow in the flow pipe to be measured according to the average value. It should be noted that the main improvement point of the present application is to optimize the sampling device of the tracer gas to improve the reliability of the sample gas, thereby improving the accuracy of the flow measurement. Since the tracer gas flow method is a mature prior art, the subsequent specific steps performed after calculating the average value are referred to the prior art, and will not be described here.

[0057] It can be understood that the above embodiments only express the preferred embodiments of the present application, which are described in detail and specifically, but cannot be understood as a limitation on the scope of the present application. It should be noted that for those skilled in the art, the above technical features can be freely combined without departing from the concept of the present application, and some modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, any equivalent transformation and modification within the scope of the claims of the present application shall belong to the scope of the claims of the present application.

Claims

1. A tracer gas sampling device, located downstream of the tracer gas injection point in the pipeline to be measured, characterized in that, The tracer gas sampling device includes: Multiple pumping mechanisms are used to mechanically connect the pipeline to be measured to simultaneously extract the sample gas after the tracer gas is mixed with the gas transported by the pipeline. Multiple gas collection elements mechanically connected one-to-one with the multiple pumping mechanisms for collecting the sample gas; and A control module electrically connected to the plurality of air extraction mechanisms and used to control the operation of the plurality of air extraction mechanisms.

2. The tracer gas sampling device according to claim 1, characterized in that, Each of the aforementioned pumping mechanisms includes a vacuum pump and a three-way valve; The inlet end of the vacuum pump is used for mechanical connection to the flow rate pipeline to be measured, and the vacuum pump is electrically connected to the control module; The outlet of the vacuum pump is mechanically connected to the first port of the three-way valve, the second port of the three-way valve is mechanically connected to the gas collecting component, the third port of the three-way valve is connected to the outside, and the three-way valve is electrically connected to the control module.

3. The tracer gas sampling device according to claim 2, characterized in that, The control module includes a control unit, multiple first switch units, and multiple second switch units; Each of the first switching units is electrically connected to each of the vacuum pumps in a one-to-one manner, and the control unit is electrically connected to each of the first switching units to control each of the vacuum pumps to start or stop simultaneously. Each of the second switching units is electrically connected to each of the three-way valves in a one-to-one manner, and the control unit is electrically connected to each of the second switching units to control the first valve port and the second valve port of each of the three-way valves to be connected simultaneously or the first valve port and the third valve port to be connected simultaneously.

4. The tracer gas sampling device according to claim 3, characterized in that, Each of the first switching units includes a first relay, the excitation coil of each first relay is electrically connected to the control unit, and the normally open contact circuit of each first relay is electrically connected one-to-one between the power supply terminal of each vacuum pump and the power supply. Each of the second switching units includes a second relay, the excitation coil of each second relay is electrically connected to the control unit, and the normally open contact circuit of each second relay is electrically connected one-to-one between the power supply terminal of each three-way valve and the power supply.

5. The tracer gas sampling device according to claim 4, characterized in that, The control unit includes a PLC controller, which is electrically connected to the excitation coils of each of the first relays and each of the second relays.

6. The tracer gas sampling device according to claim 4, characterized in that, The control module further includes a first operation unit and a second operation unit; The first operating unit is electrically connected to the control unit, and the first operating unit is used to control each of the vacuum pumps to start or stop simultaneously according to the operation. The second operating unit is electrically connected to the control unit, and the second operating unit is used to control the first valve port and the second valve port of each of the three-way valves to be connected simultaneously or the first valve port and the third valve port to be connected simultaneously according to the operation.

7. The tracer gas sampling device according to claim 1, characterized in that, Each of the gas collection components includes a sealed bag.

8. The tracer gas sampling device according to any one of claims 1 to 7, characterized in that, The number of the air extraction mechanism and the number of the gas collection components are both 6.

9. A flow measurement device, characterized in that, Includes the tracer gas sampling device as described in any one of claims 1 to 8.

10. The flow measurement device according to claim 9, characterized in that, Also includes: A gas analyzer used to analyze the concentration of sample gas in each gas collection element; as well as An analysis module used to determine the gas flow rate in the pipeline to be measured based on the concentration of each sample gas.

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