VOCs sampling multipath gas automatic sampling system

Abstract

The utility model discloses a VOCs sample introduction multipath gas automatic sample introduction system, which relates to the gas detection technology field, and comprises a plurality of gas storage tanks used for storing gas to be detected and a gas path connected with nitrogen, each gas storage tank is connected with a gas branch pipeline, the plurality of gas branch pipelines are connected with a gas branch valve, and the gas branch valve is connected with a gas pipeline. A gas preheating part for preheating gas to be detected and a shunt valve control part for controlling the gas shunt valve are arranged on the gas shunt valve; according to the utility model, the plurality of gas branch pipelines are connected with the gas branch valves, so that a valve does not need to be arranged on each gas branch pipeline, the cost of the detection equipment is saved, and after each gas detection, the gas branch valves and the gas main pipeline are purged through nitrogen, so that the gas is prevented from being blocked after a certain gas is detected. And residual detection gas in the gas branching valve and the gas main pipeline affects the subsequent detection effect.

Description

Technical Field

[0001] This utility model relates to the field of gas detection technology, specifically a VOCs multi-channel automatic gas sampling system. Background Technology

[0002] Currently, gas analysis systems connect multiple sampling channels to various sampled gases. Each sampling channel is equipped with a valve. By controlling the opening and closing of the valve in a particular sampling channel, the sampled gas flows through the main sampling channel to the detection equipment for testing. When there are many sampling channels, installing valves in each sampling channel increases the testing cost. Since the sampled gas in each sampling channel passes through the main sampling channel, the residual gas in the main sampling channel after testing a certain gas can affect the detection of subsequent gases, leading to inaccurate gas detection. Utility Model Content

[0003] To address the aforementioned shortcomings of existing technologies, this utility model provides a VOCs multi-channel automatic gas sampling system. By connecting multiple gas branch lines to gas branch valves, it eliminates the need to install valves on each gas branch line, saving on the cost of detection equipment. After each gas detection, nitrogen is used to purge the gas branch valves and the main gas line to prevent residual detection gas in the gas branch valves and the main gas line from affecting the subsequent detection results.

[0004] To achieve the above objectives, this utility model provides the following technical solution: a VOCs multi-channel automatic gas injection system, comprising multiple gas storage tanks for storing the gas to be detected and a gas path connected to nitrogen. Each gas storage tank is connected to a gas branch pipeline, and the multiple gas branch pipelines are connected to gas branch valves. Each gas branch valve is equipped with a gas preheating section for preheating the gas to be detected and a branch valve control section for controlling the gas branch valves. Each gas branch valve is connected to a main gas pipeline, and a gas detection device is connected to the main gas pipeline. A main gas pipeline heating section is provided on the main gas pipeline.

[0005] Preferably, the gas branch valve includes a valve head and a valve core. The valve head has multiple first air inlets and a first air outlet. Multiple gas branch pipelines are connected to the multiple first air inlets on the valve head, and the main gas pipeline is connected to the first air outlet on the valve head. The valve core is rotatable and is disposed at the center of the valve head. The valve core is provided with a sealing strip for separating the multiple first air inlets and the first air outlet. The valve core has a first central hole and a second air inlet. The first central hole and the second air inlet are connected in communication. The valve core is provided with an open sealing ring. The open sealing ring has multiple through holes for connecting the first central hole and the first air outlet.

[0006] Preferably, the branch valve control unit includes a control unit base, a drive motor, a reducer, and a position encoder. The control unit base is mounted on the housing, and the position encoder and reducer are disposed on the control unit base. The drive motor is connected to the reducer. A synchronous pulley A is connected to the position encoder, and a synchronous pulley B is connected to the reducer. A synchronous belt is disposed between synchronous pulley A and synchronous pulley B. A synchronous pulley shaft is disposed on synchronous pulley B. A connecting member is connected to the control unit base. The connecting member is connected to the valve head of the gas branch valve. The connecting member has a second central hole, and a connecting shaft is rotatably disposed in the second central hole. The connecting shaft is connected to the valve core of the gas branch valve.

[0007] Preferably, the gas preheating unit includes a fixed base, a temperature control sensor, a preheating rod, and a first temperature sensor. The fixed base is sleeved on the gas branch valve, and the temperature control sensor, the preheating rod, and the first temperature sensor are disposed on the fixed base.

[0008] Preferably, the gas main heating section includes a gas heating belt disposed inside the gas main pipeline, a second temperature sensor, and a gas main pipeline insulation layer disposed outside the gas main pipeline. The gas heating belt is used to heat the gas in the gas main pipeline, and the second temperature sensor is used to monitor the temperature of the gas in the gas main pipeline.

[0009] Preferably, the number of gas storage tanks is: 15 .

[0010] Preferably, the main gas pipeline and the multiple gas branch pipelines are all subjected to surface silanization treatment.

[0011] This invention provides a multi-channel automatic gas sampling system for VOCs, which has the following advantages:

[0012] 1. This utility model connects multiple gas branch lines to gas branch valves, thus eliminating the need to install valves on each gas branch line, saving the cost of detection equipment. After each gas detection, nitrogen is used to purge the gas branch valves and the main gas line to prevent residual detection gas in the gas branch valves and the main gas line from affecting the subsequent detection results after a certain gas has been detected.

[0013] 2. The gas preheating section and the gas main heating section of this utility model perform secondary heating on the gas to be detected, which can vaporize the sample and improve the accuracy and efficiency of gas analysis. The surfaces of the gas main pipeline and multiple gas sub-pipes are all treated with surface silanization to reduce the adsorption and accumulation of volatile organic compounds (VOCs) on the pipeline surface, thereby reducing the inaccuracy of the detected concentration of VOCs. Attached Figure Description

[0014] Figure 1 This is a system flowchart of the present invention;

[0015] Figure 2 This is a schematic diagram of the composition and structure of the gas heating part of this utility model;

[0016] Figure 3 This is a schematic diagram of the gas preheating unit and the branch valve control unit of this utility model;

[0017] Figure 4 This is a radial sectional view of the valve head of this utility model;

[0018] Figure 5 This is an axial sectional view of the valve head of this utility model;

[0019] Figure 6 This utility model Figure 5 Enlarged view of part A in the middle.

[0020] In the diagram: 1. Gas storage tank; 2. Gas branch pipeline; 3. Gas preheating unit; 301. Fixed base; 302. Temperature control sensor; 303. Preheating rod; 304. First temperature sensor; 4. Gas branch valve; 401. Sealing strip; 402. Perforated sealing ring; 403. Valve head; 404. Valve core; 5. Gas flow direction in the gas branch pipeline; 6. Branch valve control unit; 601. Control unit base; 602. Drive motor; 603. Reducer; 604. Position encoder; 605. Synchronous pulley A; 606. Synchronous belt; 607. Synchronous pulley B; 608. Synchronous pulley shaft; 609. Connector; 7. Gas flow direction in the main gas pipeline; 8. Gas heating unit; 801. Gas main pipeline heating unit; 802. Gas heating strip; 803. Second temperature sensor; 804. Insulation layer of the main gas pipeline; 9. Main gas pipeline. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0022] like Figure 1-6As shown, a VOCs multi-channel automatic gas injection system includes multiple gas storage tanks 1 for storing the gas to be detected and a gas path connected to nitrogen. Each gas storage tank 1 is connected to a gas branch line 2, and multiple gas branch lines 2 are connected to gas branch valves 4. Each gas branch valve 4 is equipped with a gas preheating unit 3 for preheating the gas to be detected and a branch valve control unit 6 for controlling the gas branch valve 4. Each gas branch valve 4 is connected to a main gas line 9, and a gas detection device is connected to the main gas line 9. A main gas line heating unit 801 is provided on the main gas line 9. The gas branch valves 4 include... The valve head 403 and valve core 404 are provided. The valve head 403 has multiple first air inlets and one first air outlet. Multiple gas branch lines 2 are connected to the multiple first air inlets on the valve head 403, and a main gas line 9 is connected to the first air outlet on the valve head 403. The valve core 404 is rotatable and centrally located in the valve head 403. A sealing strip 401 is provided on the valve core 404 to separate the multiple first air inlets and the first air outlet. A first central hole and a second air inlet are provided inside the valve core 404, communicating with each other. An opening sealing ring 402 is provided on the valve core 404. The sealing ring 402 has multiple through holes for connecting the first central hole and the first air outlet; the branch valve control unit 6 includes a control unit base 601, a drive motor 602, a reducer 603, and a position encoder 604. The control unit base 601 is mounted on the housing, the position encoder 604 and the reducer 603 are mounted on the control unit base 601, the drive motor 602 is connected to the reducer 603, a synchronous pulley A605 is connected to the position encoder 604, a synchronous pulley B607 is connected to the reducer 603, a synchronous belt 606 is provided between the synchronous pulleys A605 and B607, and the synchronous pulley B605... The control unit 601 is equipped with a synchronous pulley shaft 608. A connector 609 is connected to the control unit base 601. The connector 609 is connected to the valve head 403 of the gas diversion valve 4. The connector 609 has a second central hole and a connecting shaft is rotatably installed in the second central hole. The connecting shaft is connected to the valve core 404 of the gas diversion valve 4. The gas preheating unit 3 includes a fixed base 301, a temperature control sensor 302, a preheating rod 303, and a first temperature sensor 304. The fixed base 301 is sleeved on the gas diversion valve 4. The temperature control sensor 302, the preheating rod 303, and the first temperature sensor 304 are installed on the fixed base 301.The gas main heating unit 801 includes a gas heating belt 802 disposed inside the gas main pipeline 9, a second temperature sensor 803, and a gas main pipeline 9 insulation layer 804 disposed outside the gas main pipeline 9. The gas heating belt 802 is used to heat the gas in the gas main pipeline 9, and the second temperature sensor 803 is used to monitor the temperature of the gas in the gas main pipeline 9; the number of gas storage tanks 1 is: 15 The main gas pipeline 9 and the multiple gas branch pipelines 2 have all undergone surface silanization treatment.

[0023] Its detailed connection methods are well-known technologies in this field. The following mainly introduces the working principle and process, as follows:

[0024] In this utility model, the central temperature sensor 302, preheating rod 303, first temperature sensor 304, drive motor 602, position encoder 604, gas heating belt 802, and second temperature sensor 803 are all connected to an external electronic control system via wires. The first temperature sensor 304 and the second temperature sensor 803 can transmit signals to the electronic control system based on the temperature they sense. The above devices and connection methods are all existing technologies and will not be described in detail here.

[0025] According to the instruction manual Figure 1-6 It can be seen that when a certain gas needs to be detected and analyzed, the gas branch valve 4 connected to the gas storage tank 1 is opened by the branch valve control unit 6. The gas storage tank 1 is under positive pressure. When the gas branch valve 4 is opened to the gas storage tank 1, the gas can flow from the gas storage tank 1 to the gas branch valve 4. The gas preheating unit 3 preheats the gas, and then the gas flows to the main gas pipeline 9. The main gas pipeline heating unit 801 reheats the gas in the main gas pipeline 9. The preheating and reheating of the gas are to make the gas more hygienic. Moisture in the gas is instantly vaporized, improving the accuracy and efficiency of gas analysis. After reheating, the gas flows into a gas detection device (such as a gas chromatograph) for detection. After a gas has been detected, the gas branch valve 4 closes the gas branch line 2 and opens the gas line with nitrogen, allowing nitrogen to flow into the gas branch valve 4 and the main gas line 9 for purging. The purged nitrogen is discharged from the exhaust port of the gas detection device to prevent residual detection gas in the gas branch valve 4 and the main gas line 9 from affecting the accuracy and precision of subsequent detections.

[0026] One possible implementation is that when the valve core 404 of the gas branch valve 4 rotates, the second air inlet on the valve core 404 corresponds to the position of a first air inlet on a valve head 403. Gas flows from the gas storage tank 1 through the gas branch pipe 2, the first air inlet, and the second air inlet to the first central hole on the valve core 404, and then flows out through the through hole on the perforated sealing ring 402, the first air outlet, and the main gas pipeline 9. By controlling the position of the second air inlet on the valve core 404 to correspond with each first air inlet, the conduction of each gas branch pipe 2 is controlled. The sealing strip 401 and the perforated sealing ring 402 are both used to seal the first air inlet and the second air outlet.

[0027] One possible implementation is that when the gas branch valve 4 needs to switch the connected gas branch line 2, the drive motor 602 is started. The drive motor 602 drives the synchronous pulley B607 to rotate through the reducer 603. The synchronous pulley B607 drives the synchronous pulley shaft 608 and drives the synchronous pulley A605 to rotate through the synchronous belt 606. Since the position encoder 604 is connected to the synchronous pulley A605, the position encoder 604 provides real-time feedback on the position of the drive motor 602 shaft. When the synchronous pulley shaft 608 rotates, it drives the connecting shaft (not shown in the figure) in the connecting member 609 to rotate. The connecting shaft drives the valve core 404 of the gas branch valve 4 to rotate, so that different gas branch lines 2 are connected. The connecting member 609 has a through hole, and the connecting shaft rotates into the through hole. The connecting member 609 is set on the control unit base 601, and the gas branch valve 4 is set on the connecting member 609. A high thermal conductivity grease is applied at the contact point between the lower end of the fixed base 301 and the upper end of the gas branch valve 4.

[0028] One possible implementation is that the fixed base 301 is fixedly sleeved on the gas diversion valve 4 by a set screw. The control base is provided with a heating chamber, which is connected to the first center hole opened on the valve core 404. When the gas to be tested is flowing through the gas diversion valve 4, the control system and the temperature sensor 302 adjust the heating temperature of the preheating rod 303 to heat the gas in the heating chamber. The first temperature sensor 304 feeds back the gas temperature to the control system to achieve the effect of constant temperature control.

[0029] One possible implementation is that the gas heating belt 802 has a temperature regulation function and can control the heating temperature, the second temperature sensor 803 monitors the gas temperature in the gas main pipeline 9, and the gas main pipeline 9 insulation layer 804 is set on the outside of the gas main pipeline 9 to insulate the gas main pipeline 9.

[0030] One possible implementation is to have 15 gas storage tanks 1, which are used to store the gas to be tested and analyzed.

[0031] One possible implementation is that the surfaces of the main gas pipeline 9 and the multiple gas branch pipelines 2 are all treated with surface silanization to reduce the adsorption and accumulation of volatile organic compounds (VOCs) on the pipeline surfaces, thereby reducing the inaccuracy of the detected concentration of VOCs.

[0032] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A VOCs sample multi-channel gas automatic sampling system, characterized in that, The application relates to a gas detection device, which comprises a plurality of gas storage tanks (1) for storing the gas to be detected and a gas circuit connected with nitrogen, a gas sub-pipe (2) connected with each of the gas storage tanks (1), a gas sub-pipe valve (4) connected with the plurality of gas sub-pipes (2), a gas preheating part (3) arranged on the gas sub-pipe valve (4) and used for preheating the gas to be detected, a sub-pipe valve control part (6) arranged on the gas sub-pipe valve (4) and used for controlling the gas sub-pipe valve (4), a gas main pipe (9) connected with the gas sub-pipe valve (4), a gas detection device connected with the gas main pipe (9), and a gas main pipe heating part (801) arranged on the gas main pipe (9).

2. The VOCs sampling multi-channel gas automatic sampling system according to claim 1, wherein, The gas sub-pipe valve (4) comprises a valve head (403) and a valve core (404), a plurality of first gas inlets and a first gas outlet are arranged on the valve head (403), the plurality of gas sub-pipes (2) are connected with the plurality of first gas inlets on the valve head (403), the gas main pipe (9) is connected with the first gas outlet on the valve head (403), the valve core (404) is arranged at the center of the valve head (403) and penetrates the valve head (403), a sealing band (401) is arranged on the valve core (404) and used for separating the plurality of first gas inlets and the first gas outlet, a first center hole and a second gas inlet are arranged in the valve core (404) and are in communication connection, an open hole sealing ring (402) is arranged on the valve core (404), and a plurality of through holes for connecting the first center hole and the first gas outlet are arranged on the open hole sealing ring (402).

3. The VOCs sampling multi-channel gas automatic sampling system according to claim 2, characterized in that, The sub-pipe valve control part (6) comprises a control part base (601), a driving motor (602), a speed reducer (603) and a position encoder (604), the control part base (601) is arranged on a shell, the position encoder (604) and the speed reducer (603) are arranged on the control part base (601), the driving motor (602) is connected with the speed reducer (603), a synchronous wheel A (605) is connected with the position encoder (604), a synchronous wheel B (607) is connected with the speed reducer (603), a synchronous belt (606) is arranged between the synchronous wheel A (605) and the synchronous wheel B (607), a synchronous wheel shaft (608) is arranged on the synchronous wheel B (607), a connecting piece (609) is connected with the control part base (601), the connecting piece (609) is connected with the valve head (403) of the gas sub-pipe valve (4), a second center hole is arranged on the connecting piece (609) and a connecting shaft is arranged in the second center hole in a rotating mode, and the connecting shaft is connected with the valve core (404) of the gas sub-pipe valve (4).

4. The VOCs sampling multi-channel gas automatic sampling system according to claim 3, characterized in that, The gas preheating part (3) comprises a fixed base (301), a temperature control sensor (302), a preheating rod (303) and a first temperature sensor (304), the fixed base (301) is sleeved on the gas sub-pipe valve (4), and the temperature control sensor (302), the preheating rod (303) and the first temperature sensor (304) are arranged on the fixed base (301).

5. The VOCs sampling multipath gas automatic sampling system according to claim 1, wherein, The gas main heating part (801) comprises a gas heating belt (802) arranged in the gas main pipe (9), a second temperature sensor (803) and a gas main pipe (9) heat preservation layer (804) arranged outside the gas main pipe (9), the gas heating belt (802) is used for heating the gas in the gas main pipe (9), and the second temperature sensor (803) is used for monitoring the temperature of the gas in the gas main pipe (9).

6. The VOCs sampling multipath gas automatic sampling system according to claim 1, wherein, The number of the gas storage tanks (1) is 15.

7. The VOCs sampling multipath gas automatic sampling system according to claim 1, wherein, The gas main pipe (9) and the plurality of gas branch pipes (2) are subjected to surface silanization treatment.

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