Meterable negative pressure extraction pipe

Abstract

The utility model relates to the technical field of chemical engineering, in particular to a measurable negative pressure extraction pipe, which is characterized in that one end of an extraction pipe body positioned at the end part is communicated with a buffer tank, the extraction pipe body positioned at the end part is connected with a flow meter for measurement, and a plurality of baffle plates are connected with two opposite sides in the buffer tank in a staggered manner; and the bottom end of one side of the buffer tank communicates with a connecting pipe. The device has the beneficial effects that when the pump suddenly accelerates and the pressure in the extraction pipe body is suddenly reduced, gas stored in the buffer tank can be quickly supplemented to the extraction pipe body, and the situation that gas emission at an extraction point is unstable due to sudden rising of negative pressure is avoided; and redundant gas can be temporarily stored in the buffer tank, the pressure rising speed is slowed down, so that the water hammer effect or pipeline deformation is prevented, the buffer tank stabilizes the pressure in the extraction pipe body in the extraction process, negative pressure fluctuation is reduced, and then the gas extraction efficiency is improved.

Description

Technical Field

[0001] This utility model relates to the field of chemical technology, and in particular to a meterable negative pressure extraction pipe. Background Technology

[0002] Negative pressure extraction of methane gas refers to the technical means of extracting methane gas from coal seams, goafs, or other methane accumulation areas by creating negative pressure in pipelines or spaces using mechanical equipment, thereby achieving methane extraction, utilization, or safe discharge.

[0003] Negative pressure extraction pipes are common equipment used in negative pressure gas extraction. The extraction pipe is connected to a negative pressure pump. When the pump starts, it creates negative pressure within the extraction pipe. After the pipe is inserted into the coal seam, it extracts the gas. During extraction, the initial suction force after pump startup is too strong, creating a large negative pressure gradient in the pipeline within a short time. When the pump suddenly stops, the high-speed flowing gas decelerates abruptly, converting kinetic energy into pressure energy, generating a negative pressure wave reflection and producing a water hammer effect. Furthermore, during extraction, when new fractures or faults are exposed at the coal face, the high-pressure gas accumulated in the coal seam is released instantaneously, surging into the low-pressure pipeline and forming a positive pressure wave, causing turbulence and vibration. In the later stages of extraction, the coal seam gas pressure decreases, and the gas flow rate decreases, causing a sudden increase in pipeline negative pressure. If the vacuum pump's suction capacity remains unchanged, the absolute pressure inside the pipeline further decreases. Excessive negative pressure may collapse coal seam fractures and block gas channels. Therefore, during gas extraction, changes in coal seam gas pressure or pump start-stop operations can cause fluctuations in pipeline negative pressure, affecting extraction efficiency. Utility Model Content

[0004] The purpose of this invention is to address the shortcomings of existing technologies where changes in coalbed gas pressure or pump start-up and shutdown can cause negative pressure fluctuations in pipelines, affecting extraction efficiency. This invention proposes a measurable negative pressure extraction pipe.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] Design a measurable negative pressure extraction pipe, including a plurality of extraction pipe bodies connected in sequence. One end of the extraction pipe body located at the end is connected to a buffer tank. A flow meter for measurement is connected to the extraction pipe body located at the end. A plurality of baffles are staggered on opposite sides inside the buffer tank. A connecting pipe is connected to the bottom of one side of the buffer tank.

[0007] Preferably, the extraction pipe body is a stainless steel pipe, and the inner wall of the extraction pipe body is coated with a polyurea anti-corrosion coating.

[0008] Preferably, a check valve is connected to the extraction pipe body located at the end.

[0009] Preferably, a spring diaphragm regulating valve is connected to the connecting pipe.

[0010] Preferably, one end of the connecting pipe is connected to a metal bellows compensator, and one end of the metal bellows compensator is connected to a connector.

[0011] Preferably, the metal bellows compensator and the connector are an integral structure.

[0012] Preferably, a fixed frame is fixedly connected to the bottom of the buffer tank, a filter is fixedly connected to the fixed frame, the filter is located outside the inlet end of the connecting pipe, a drain pipe is connected to the bottom of the buffer tank, and a sealing cap is connected to the bottom of the drain pipe.

[0013] Preferably, the filter is a stainless steel wire mesh coalescer.

[0014] The present invention proposes a measurable negative pressure extraction tube, the advantages of which are as follows:

[0015] When the pump suddenly accelerates, causing a sharp drop in pressure inside the extraction pipe, the gas stored in the buffer tank is quickly replenished to the extraction pipe, preventing unstable gas outbursts at the extraction point caused by a sudden increase in negative pressure. When the pump stops or a sudden change in coal seam gas pressure causes a sharp increase in pressure inside the extraction pipe, excess gas can be temporarily stored in the buffer tank to slow down the rate of pressure increase, thereby preventing water hammer or pipe deformation. During the extraction process, the buffer tank stabilizes the pressure inside the extraction pipe, reduces negative pressure fluctuations, and thus improves gas extraction efficiency. Attached Figure Description

[0016] Figure 1 This invention provides a structural schematic diagram of a measurable negative pressure extraction pipe. Figure 1 ;

[0017] Figure 2 This invention provides a structural schematic diagram of a measurable negative pressure extraction pipe. Figure 2 ;

[0018] Figure 3 This is a schematic diagram of the connection between the connecting pipe and the metal bellows compensator in a meterable negative pressure extraction pipe proposed in this utility model.

[0019] Figure 4 This is a cross-sectional view of the connection between the connecting pipe and the metal bellows compensator in a meterable negative pressure extraction pipe proposed in this utility model.

[0020] In the diagram: 1. Extraction pipe body; 2. Buffer tank; 3. Flow meter; 4. Baffle plate; 5. Connecting pipe; 6. Check valve; 7. Spring diaphragm regulating valve; 8. Metal bellows compensator; 9. Connector; 10. Fixing frame; 11. Filter; 12. Drain pipe; 13. Sealing cap. 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 of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0022] Example 1: Refer to Figure 1-4 A measurable negative pressure extraction pipe includes several extraction pipe bodies 1, each made of stainless steel. The inner wall of each extraction pipe body 1 is coated with a polyurea anti-corrosion coating. Several extraction pipe bodies 1 are connected in sequence. One end of the extraction pipe body 1 at the end is connected to a buffer tank 2. A flow meter 3 for measurement is connected to the extraction pipe body 1 at the end. The flow meter 3 is an ultrasonic flow meter. Several baffles 4 are staggered on opposite sides inside the buffer tank 2. A connecting pipe 5 is connected to the bottom of one side of the buffer tank 2. A check valve 6 is connected to the extraction pipe body 1 at the end. A spring diaphragm regulating valve 7 is connected to the connecting pipe 5.

[0023] Work process:

[0024] Connecting pipe 5 is connected to an external negative pressure pump. After the negative pressure pump is started, it draws gas from the buffer tank 2 through connecting pipe 5, creating a negative pressure inside the buffer tank 2. Since the extraction pipe body 1 is connected to the buffer tank 2, a negative pressure is also generated inside the extraction pipe body 1, thereby realizing the extraction of gas. Flow meter 3 is used to measure the flow rate of the extracted gas. The extracted gas enters the buffer tank 2. Check valve 6 prevents the gas in the buffer tank 2 from flowing back. The gas in the buffer tank 2 is released from connecting pipe 5. Spring diaphragm regulating valve 7 can automatically adjust the opening according to the set pressure, thereby controlling the pressure inside the buffer tank 2.

[0025] When the pump suddenly accelerates, causing a sudden drop in pressure inside the extraction pipe 1, the gas stored in the buffer tank 2 will quickly replenish the extraction pipe 1 to prevent the gas outburst at the extraction point from becoming unstable due to a sudden increase in negative pressure. When the pump stops or the coal seam gas pressure changes suddenly, causing a sudden increase in pressure inside the extraction pipe 1, the excess gas can be temporarily stored in the buffer tank 2 to slow down the rate of pressure increase, thereby preventing water hammer effect or pipe deformation. During the extraction process, the buffer tank 2 stabilizes the pressure inside the extraction pipe 1, reduces negative pressure fluctuations, and thus improves the gas extraction efficiency.

[0026] At the same time, when the gas enters the buffer tank 2 and comes into contact with several baffles 4, the baffles 4 force the airflow to change direction multiple times, converting kinetic energy into turbulent energy dissipation, reducing flow velocity fluctuations, prolonging the residence time of the gas in the tank, reducing the peak pressure fluctuation, and enhancing the buffering effect.

[0027] Example 2: Vibration transmission and thermal stress deformation between connecting pipe 5 and buffer tank 2 may cause weld cracking, refer to... Figure 1 As another preferred embodiment of this utility model, the difference from embodiment 1 is that one end of the connecting pipe 5 is connected to a metal bellows compensator 8, and one end of the metal bellows compensator 8 is connected to a connector 9. The metal bellows compensator 8 and the connector 9 are an integral structure. The connector 9 is connected to the inlet end of the negative pressure pump. The metal bellows compensator 8 absorbs the thermal expansion and contraction and vibration of the pipeline, making the connection between the connecting pipe 5 and the buffer tank 2 less prone to cracking.

[0028] Example 3: When the gas is discharged into the pump body through the connecting pipe 5, the gas contains liquid. The liquid droplets damage the pump body, reducing the service life of the pump. (Refer to...) Figure 3-4 As another preferred embodiment of this utility model, the difference from embodiment 1 is that a fixed frame 10 is fixedly connected to the bottom of the buffer tank 2, and a filter 11 is fixedly connected to the fixed frame 10. The filter 11 is a stainless steel wire mesh coalescer. The filter 11 is located outside the inlet end of the connecting pipe 5. The bottom end of the buffer tank 2 is connected to a drain pipe 12, and the bottom end of the drain pipe 12 is connected to a sealing cap 13.

[0029] The fixed frame 10 fixes the filter 11. Gas with droplets comes into contact with the filter 11, and the filter 11 filters the droplets in the gas to prevent liquid from entering the pump and reduce damage to the pump. The gas passes through the filter 11, and the liquid is filtered out by the filter 11 and falls to the bottom of the buffer tank 2. After the pumping is finished, the sealing cover 13 is removed, and the water at the bottom of the buffer tank 2 is released from the drain pipe 12 to prevent excessive water accumulation from being carried away by the airflow.

[0030] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A meterable negative pressure extraction pipe, comprising a plurality of extraction pipe bodies (1), the plurality of extraction pipe bodies (1) are connected in sequence, characterized in that, in: One end of the extraction pipe body (1) located at the end is connected to a buffer tank (2), and a flow meter (3) for measurement is connected to the extraction pipe body (1) located at the end. Several baffles (4) are staggered on opposite sides inside the buffer tank (2), and a connecting pipe (5) is connected to the bottom of one side of the buffer tank (2).

2. The quantifiable negative pressure extraction tube of claim 1, wherein, The extraction pipe body (1) is a stainless steel pipe, and the inner wall of the extraction pipe body (1) is coated with a polyurea anti-corrosion coating.

3. The measurable negative pressure extraction pipe according to claim 1, characterized in that, A check valve (6) is connected to the extraction pipe body (1) located at the end.

4. The quantifiable negative pressure extraction tube of claim 1, wherein, A spring diaphragm regulating valve (7) is connected to the connecting pipe (5).

5. The quantifiable negative pressure extraction tube of claim 4, wherein, One end of the connecting pipe (5) is connected to a metal bellows compensator (8), and one end of the metal bellows compensator (8) is connected to a connector (9).

6. The quantifiable negative pressure extraction tube of claim 5, wherein, The metal bellows compensator (8) and the connector (9) are an integral structure.

7. The quantifiable negative pressure extraction tube of claim 1, wherein, The buffer tank (2) is fixedly connected to a fixed frame (10) at its bottom. A filter (11) is fixedly connected to the fixed frame (10). The filter (11) is located outside the inlet end of the connecting pipe (5). The bottom end of the buffer tank (2) is connected to a drain pipe (12). The bottom end of the drain pipe (12) is connected to a sealing cap (13).

8. The quantifiable negative pressure extraction tube of claim 7, wherein, The filter (11) is a stainless steel wire mesh coalescer.

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