Gas pump negative pressure pipeline gas extraction device

Abstract

The utility model relates to negative pressure pipeline gas sampling technical field, concretely is a kind of gas pump negative pressure pipeline gas extraction device. Including air inlet cylinder and back cylinder, air inlet cylinder and back cylinder lower part are respectively sealed and inserted into gas pump air inlet pipe, and the bottom end of air inlet cylinder and back cylinder is respectively provided with negative pressure drain hole, and the top of air inlet cylinder is connected with first hose, and the top of back cylinder is connected with second hose, and first hose and second hose are used to be connected with methane sensor through pipeline to form closed gas sample flow path, and air inlet cylinder is provided with gas sampling hole on the side wall of cylinder body in the air inlet pipe of gas pump, and back cylinder is provided with gas backflow hole on the side wall of cylinder body in the air inlet pipe of gas pump. By adopting double-cylinder structure that gas sampling hole and gas backflow hole are respectively arranged, and closed gas sample flow path is established between the two, the pressure difference generated by negative pressure environment in pipeline itself is used as power, the effective extraction and circulation of gas sample in pipeline are realized.

Description

Technical Field

[0001] This utility model relates to the field of negative pressure pipeline gas sampling technology, specifically a gas extraction device for a gas pump negative pressure pipeline. Background Technology

[0002] In the field of coal mine safety production, the gas extraction system is the core component for preventing gas disasters. Surface and underground gas pumping stations continuously extract methane gas through negative pressure pipelines, and real-time and accurate monitoring of methane concentration in the pipelines is an important basis for evaluating the extraction effect and ensuring the safe operation of the system.

[0003] Currently, in practical applications of gas concentration monitoring in negative pressure pipelines, the common method is to create a single inlet in the pipeline and directly extend and insert the inlet probe of a methane sensor into the pipeline for measurement. However, due to the extremely high negative pressure at the inlet of the gas pump during operation, and the fact that the extracted gas usually contains a certain amount of water vapor, this traditional single-inlet insertion direct measurement method faces significant challenges. The intense negative pressure environment inside the pipeline makes it difficult for the sensor's small inlet to effectively extract gas samples, while the accumulation of water vapor further obstructs the airflow path and may even damage the sensor's sensitive elements. These factors collectively lead to deviations in the monitoring results; the measured values ​​are often lower than the actual concentration, or even impossible to obtain valid readings, thus introducing uncertainty into the safety assessment and process control of the extraction system. Utility Model Content

[0004] The present invention aims to solve the above problems, thereby providing a gas extraction device for a gas pump negative pressure pipeline that improves detection accuracy.

[0005] The technical solution adopted by this utility model to solve the aforementioned problem is: A gas extraction device for a gas pump negative pressure pipeline includes an inlet cylinder and a return cylinder. The lower parts of the inlet cylinder and the return cylinder are respectively sealed and inserted into the gas pump inlet pipe. Negative pressure drain holes are respectively provided at the bottom ends of the inlet cylinder and the return cylinder. A first flexible tube is connected to the top of the inlet cylinder, and a second flexible tube is connected to the top of the return cylinder. The first flexible tube and the second flexible tube are used to connect with a methane sensor through pipeline to form a closed gas sample flow path. A gas sampling hole is provided on the side wall of the inlet cylinder inside the gas pump inlet pipe, and a gas return hole is provided on the side wall of the return cylinder inside the gas pump inlet pipe.

[0006] Compared with the prior art, the outstanding features of this utility model, which adopts the above technical solution, are: By employing a dual-cylinder structure with separate gas sampling and return ports, and establishing a closed gas flow path between them, the effective extraction and circulation of gas samples within the pipeline are achieved by utilizing the pressure difference generated by the negative pressure environment within the pipeline. This method increases the gas sample throughput through the sensor, helping to mitigate measurement deviations caused by excessive negative pressure or insufficient sampling. Simultaneously, the bottom negative pressure drain hole allows collected liquid to drain back into the pipeline, reducing the interference and potential damage to sensor measurements caused by water vapor accumulation, thereby improving the reliability of monitoring results.

[0007] As a preferred embodiment, a further technical solution of this utility model is: Furthermore, the gas return orifice faces away from the main direction of airflow in the gas pump inlet pipe. This structure helps to utilize the low-pressure vortex region naturally generated on the back-flow side when the fluid flows through the cylinder, thereby creating a relatively lower local pressure at the orifice. This enhances the suction force for the gas flowing back to the main pipeline from the sensor, providing a more stable power source for the entire gas sample circulation path.

[0008] Furthermore, the air inlet cylinder is rotatably connected to the gas pump inlet pipe. Rotating the air inlet cylinder adjusts the orientation of the gas sampling hole in the pipeline. Operators can optimize the orientation of the gas sampling hole according to the specific flow conditions in the pipeline, thereby improving the sampling effect.

[0009] Furthermore, along the airflow direction, the air inlet is positioned upstream of the return air inlet. This arrangement conforms to the flow characteristics of the fluid, allowing the sampling point to be located upstream of the return point. This facilitates the use of the airflow's kinetic energy, enabling the extracted gas sample to enter the sampling port more smoothly and reducing the flow field interference of the downstream return process on the upstream sampling point, thus helping to maintain the stability of the entire sampling cycle. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the structure during operation of an embodiment of the present invention; Figure 2 This is a schematic diagram of the air intake cylinder according to an embodiment of the present utility model; The following are labeled in the diagram: 1. Inlet cylinder; 2. Outlet cylinder; 3. Gas pump inlet pipe; 4. First hose; 5. Second hose; 6. Methane sensor; 7. Gas sampling port; 8. Gas return port; 9. Negative pressure drain port. Detailed Implementation

[0011] The present invention will be further described below with reference to embodiments, the purpose of which is only to better understand the content of the present invention. Therefore, the examples given do not limit the scope of protection of the present invention.

[0012] A gas extraction device for a gas pump negative pressure pipeline includes an inlet cylinder 1 and a return cylinder 2. The lower parts of the inlet cylinder 1 and the return cylinder 2 are respectively sealed and inserted into the gas pump inlet pipe 3. Negative pressure drain holes 9 are respectively provided at the bottom ends of the inlet cylinder 1 and the return cylinder 2. A first flexible tube 4 is connected to the top of the inlet cylinder 1, and a second flexible tube 5 is connected to the top of the return cylinder 2. The first flexible tube 4 and the second flexible tube 5 are used to connect with a methane sensor 6 through pipelines to form a closed gas sample flow path. A gas sampling hole 7 is provided on the side wall of the cylinder body inside the gas pump inlet pipe 3. A gas return hole 8 is provided on the side wall of the cylinder body inside the gas pump inlet pipe 3. The main structures of the inlet cylinder 1 and the return cylinder 2 are the same. Gas containing water vapor enters the inlet cylinder 1 through the gas sampling hole 7. Due to the relatively large space inside the cylinder, the airflow velocity will decrease instantly. The gas is cooled due to contact with the cooler cylinder wall. The decrease in flow velocity and temperature change will cause the water vapor to condense into liquid water. Since the density of liquid is much greater than that of gas, the condensate will naturally sink under the influence of gravity and collect at the bottom of the air inlet cylinder 1. The entire gas pump air inlet pipe 3 is a continuous, high negative pressure environment. Since the air inlet cylinder 1 is connected to the gas pump air inlet pipe 3 through the gas sampling port 7, its interior is also in a negative pressure state, but its pressure value may be slightly higher than the pressure inside the gas pump air inlet pipe 3. Especially when the sampling port is set to the side, since the other side of the negative pressure drain hole 9 is the gas pump air inlet pipe 3 with lower pressure, this pressure difference will generate a continuous suction force, which will draw the liquid out through the negative pressure drain hole 9 and discharge it back into the airflow of the gas pump air inlet pipe 3.

[0013] Furthermore, the gas return orifice 8 faces away from the main direction of airflow in the gas pump inlet pipe 3. This structure helps to utilize the low-pressure vortex region naturally generated on the back-flow side when the fluid flows through the cylinder, thereby forming a relatively lower local pressure at the orifice, enhancing the suction force for the gas flowing back to the main pipeline from the sensor, and providing a more stable power source for the entire gas sample circulation path.

[0014] Furthermore, the air inlet cylinder 1 is rotatably connected to the gas pump inlet pipe 3. Rotating the air inlet cylinder 1 adjusts the orientation of the gas sampling hole 7 in the pipeline. The most commonly used angle is when the axis of the gas sampling hole 7 is perpendicular to the gas pump inlet pipe 3. It can also be rotated left and right within ±45°. Operators can optimize the orientation of the gas sampling hole 7 according to the specific flow conditions in the pipeline on site, thereby improving the sampling effect.

[0015] Furthermore, along the airflow direction, the air inlet cylinder 1 is positioned upstream of the return cylinder 2. This arrangement conforms to the flow characteristics of the fluid, allowing the sampling point to be located upstream of the return point. This facilitates the use of the kinetic energy of the airflow, enabling the extracted gas sample to enter the sampling hole more smoothly and reducing the flow field interference of the downstream return process on the upstream sampling point, thus helping to maintain the stability of the entire sampling cycle.

[0016] The above description is only a preferred embodiment of the present utility model and does not limit the scope of the present utility model. All equivalent changes made based on the content of the present utility model specification and its drawings are included within the scope of the present utility model.

Claims

1. A gas extraction device for a gas pump negative pressure pipeline, characterized in that: It includes an air inlet cylinder and an air return cylinder. The lower parts of the air inlet cylinder and the air return cylinder are respectively sealed and inserted into the gas pump inlet pipe. The bottom of the air inlet cylinder and the air return cylinder are respectively provided with negative pressure drainage holes. The top of the air inlet cylinder is connected to a first flexible hose, and the top of the air return cylinder is connected to a second flexible hose. The first flexible hose and the second flexible hose are used to connect with the methane sensor through pipelines to form a closed gas sample flow path. The air inlet cylinder has a gas sampling hole on the side wall of the cylinder body inside the gas pump inlet pipe, and the air return cylinder has a gas return hole on the side wall of the cylinder body inside the gas pump inlet pipe.

2. The gas extraction device for a gas pump negative pressure pipeline according to claim 1, characterized in that: The gas return hole faces away from the main direction of airflow in the gas pump inlet pipe.

3. The gas extraction device for a gas pump negative pressure pipeline according to claim 2, characterized in that: The air inlet cylinder is rotatably connected to the gas pump inlet pipe, and rotating the air inlet cylinder adjusts the orientation of the gas sampling port inside the pipe.

4. The gas extraction device for a gas pump negative pressure pipeline according to claim 1, characterized in that: Along the airflow direction, the air intake is located upstream of the air return.

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