Negative pressure drainage pump

Abstract

The invention relates to the technical field of coal bed gas mining equipment, in particular to a negative pressure drainage and mining pump which comprises a working pump cylinder and a production pump core, a working ring cavity and a working inner cavity are formed in the working pump cylinder, the production pump core is detachably connected to the working inner cavity, a liquid channel and a mixing cavity are formed in the production pump core, and the liquid channel is communicated with the working ring cavity. The top of the liquid channel is communicated with the working inner cavity, the bottom end of the liquid channel is communicated with the working ring cavity, the mixing cavity is communicated with the working ring cavity and the liquid channel, and the bottom end of the working ring cavity is communicated with the working inner cavity. According to the negative pressure drainage and mining pump, the defect that a pump core needs to be replaced when the working condition changes greatly in traditional construction is overcome, the production cost is reduced, and the drainage and mining efficiency of coal bed gas is improved.

Description

Technical Field

[0001] The invention relates to the technical field of coalbed methane mining equipment, and in particular to a negative pressure drainage pump. Background Art

[0002] During the coalbed methane drainage process, the jet pump uses high-pressure water as the power fluid to lift the downhole liquid. First, the high-pressure power fluid flows down from the wellhead along the power fluid pipe string to the downhole jet pump. When the power fluid passes through the nozzle in the pump, the pressure energy is converted into kinetic energy, causing the pressure of the fluid to drop sharply, forming a negative pressure area around the nozzle. At this time, the formation fluid enters the pump under the action of the formation pressure and is sucked into the negative pressure area. The formation fluid entering the negative pressure area mixes with the high-speed jet liquid at the nozzle outlet to form a mixed liquid in the throat. In this process, the kinetic energy of the mixed liquid is converted into pressure energy, the formation fluid obtains energy from the power fluid and gradually increases the pressure, and finally lifts the liquid to the ground through the mixed liquid pipe string.

[0003] In coalbed methane wells, the underground space is small. If other devices are to be installed underground, the existing negative pressure drainage pump volume does not support the layout of its pipeline, and the negative pressure drainage must be designed according to a certain working condition. In actual application, when the working condition of the coalbed methane well changes greatly, in order to ensure the drainage efficiency, a pump core that meets the working condition must be replaced, resulting in increased production costs. In order to solve the above problems, this patent proposes a negative pressure drainage pump with a new structure. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the related art. To this end, the present invention provides a negative pressure drainage pump, which solves the disadvantage of needing to replace the pump core when the working conditions change greatly in traditional construction, reduces production costs, and improves the drainage efficiency of coalbed methane.

[0005] The present invention provides a negative pressure drainage pump, comprising a working pump barrel and a production pump core, the working pump barrel is formed with a working annular cavity and a working inner cavity, the production pump core is detachably connected to the working inner cavity, a liquid channel and a mixing cavity are formed inside the production pump core, the top of the liquid channel is connected to the working inner cavity and the bottom end is connected to the working annular cavity, the mixing cavity is connected to the working annular cavity and the liquid channel, and the bottom end of the working annular cavity is connected to the working inner cavity.

[0006] A further improvement of the negative pressure production pump of the present invention is that the working pump barrel includes a pump core tube, an inner pump barrel and a jet pump barrel, the second end of the inner pump barrel is inserted into the pump core tube, the first end of the jet pump barrel is sleeved and connected to the second end of the inner pump barrel, the production pump core is located in the inner pump barrel and the jet pump barrel, the working annular cavity is formed between the pump core tube and the inner pump barrel and between the pump core tube and the jet pump barrel, and the inner pump barrel and the jet pump barrel form the working inner cavity.

[0007] A further improvement of the negative pressure drainage pump of the present invention is that a plurality of pump barrel support blocks are formed on the outer wall of the jet pump barrel, the pump barrel support blocks abut against the inner wall of the pump core tube, and a pump barrel support block located at the bottom end of the jet pump barrel is annular.

[0008] A further improvement of the negative pressure drainage pump of the present invention is that the production pump core includes an upper fishing head, an upper liquid inlet bridge, an upper sealing cavity, a nozzle, a positioning sleeve, a pressurizing cavity, a lower sealing cavity, a lower liquid inlet bridge, a locking sleeve and a lower fishing head, the mixing cavity is formed between the outer side wall of the nozzle and the positioning sleeve, and a fourth through hole is opened on the positioning sleeve; A mixing chamber is formed between the nozzle and the positioning sleeve, and the mixing chamber is connected to the working ring chamber. The inner wall of the jet pump barrel is recessed inwardly at a position corresponding to the mixing chamber to form a first buffer groove. A first through hole is provided on the inner wall of the jet pump barrel at a position corresponding to the mixing chamber. The inner wall of the jet pump barrel protrudes inwardly at a position corresponding to the locking sleeve to form a shoulder. The locking sleeve is inserted and connected to the shoulder. A third through hole is provided on the jet pump barrel below the shoulder. A second through hole is provided on the jet pump barrel at a position corresponding to the lower liquid inlet bridge. The fourth through hole is connected to the first buffer groove and the first through hole.

[0009] A further improvement of the negative pressure drainage pump of the present invention is that a boosting connecting groove is formed at the position of the boosting cavity corresponding to the nozzle, a boosting cavity channel is formed inside the boosting cavity, the boosting cavity channel is connected to the boosting connecting groove, and the inner diameter of the boosting cavity channel close to the nozzle position is smaller than the inner diameter away from the nozzle position.

[0010] A further improvement of the negative pressure drainage pump of the present invention is that the inner diameter of the nozzle at a position close to the pressurization cavity is smaller than the inner diameter at a position far from the pressurization cavity.

[0011] A further improvement of the negative pressure drainage pump of the present invention is that a plurality of upper liquid inlet channels are spaced apart on the top of the upper liquid inlet bridge, and a first channel is formed in the middle of the upper liquid inlet bridge, and the first channel is a part of the liquid channel.

[0012] A further improvement of the negative pressure drainage pump of the present invention is that a lower liquid inlet channel is opened in the middle of the lower liquid inlet bridge, the bottom end of the lower liquid inlet channel is in a closed state, the lower liquid inlet channel is a part of the liquid channel, and a lower liquid inlet channel is opened on the side of the lower liquid inlet bridge, and the lower liquid inlet channel is connected to the second through hole.

[0013] A further improvement of the negative pressure drainage pump of the present invention is that an upper sealing rubber tube is sleeved on the outer side wall of the upper sealing cavity, and the upper sealing rubber tube abuts against the inner side wall of the inner pump tube; The outer side wall of the lower sealing cavity is sleeved with a lower sealing rubber tube, and the lower sealing rubber tube abuts against the inner side wall of the pump barrel of the jet pump.

[0014] A further improvement of the negative pressure drainage pump of the present invention is that the locking sleeve is provided with an insertion cavity, the lower salvage head is inserted into the insertion cavity, and a plurality of fixing ears are provided on the side of the locking sleeve, which are inserted into the shoulder through the fixing ears so that the locking sleeve is fixed to the pump barrel of the jet pump.

[0015] The production pump core in the embodiment of the present invention can choose whether to add a working pump barrel as needed, avoiding the replacement of the entire negative pressure drainage pump and the pump pipe, improving the construction efficiency and reducing the production cost. In this application, a locking sleeve, a shoulder and a pump barrel support block are provided to improve the connection stability of the production pump core in the working pump barrel. Through the nozzle, positioning sleeve and booster cavity of the production pump core, it is convenient to change the dynamic state of the mixed liquid, thereby facilitating the drainage operation of coalbed methane.

[0016] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a schematic diagram of a negative pressure drainage pump provided in an embodiment of the present invention.

[0019] Figure 2 It is a node schematic diagram of the negative pressure drainage pump provided in an embodiment of the present invention.

[0020] Figure 3 It is a node schematic diagram of the negative pressure drainage pump provided by an embodiment of the present invention installed behind the screen pipe.

[0021] Figure 4 It is a schematic diagram of the working pump barrel of the negative pressure drainage pump provided in an embodiment of the present invention.

[0022] Figure 5 It is a schematic diagram of a production pump core of a negative pressure drainage pump provided in an embodiment of the present invention.

[0023] Figure 6 It is a schematic diagram of a locking sleeve of a negative pressure drainage pump provided in an embodiment of the present invention.

[0024] Reference numerals: 1. First tubing coupling; 2. Inner pump barrel; 3. Second tubing coupling; 4. Pump barrel reducer; 5. Pump core tube; 6. Upper fishing head; 7. Upper liquid inlet bridge; 8. Upper sealing cavity; 9. Upper sealing rubber cylinder; 10. Jet pump barrel; 11. Nozzle; 12. Positioning sleeve; 13. Pressurization cavity; 14. Lower sealing cavity; 15. Lower sealing rubber cylinder; 16. Lower liquid inlet bridge; 17. Locking sleeve; 18. Lower fishing head; 19. Inner barrel fixing sleeve; 20. Conversion joint; 21. Screen tube plug; 22. Coupling; 23. Screen tube joint; 24. Third tubing coupling; 25. Screen tube; 26. Jet pipe string; 1001. First through hole; 1002. Second through hole; 1003. Third through hole; 1004. Shoulder; 1701. Fixing ear; 1702. Insertion cavity. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. The following embodiments are used to illustrate the present invention, but cannot be used to limit the scope of the present invention.

[0026] Combine the following Figure 1 The negative pressure drainage pump of the present invention includes a working pump barrel and a production pump core. The working pump barrel is formed with a working annular cavity and a working inner cavity. The production pump core is detachably connected to the working inner cavity. A liquid channel and a mixing cavity are formed inside the production pump core. The top of the liquid channel is connected to the working inner cavity and the bottom is connected to the working annular cavity. The mixing cavity is connected to the working annular cavity and the liquid channel. The bottom end of the working annular cavity is connected to the working inner cavity.

[0027] In a preferred embodiment of the negative pressure drainage pump of the present invention, Figure 2As shown, the working pump barrel includes a pump core tube 5, an inner pump barrel 2 and a jet pump barrel 10, the second end of the inner pump barrel 2 is inserted into the pump core tube 5, the first end of the jet pump barrel 10 is sleeved and connected to the second end of the inner pump barrel 2, the production pump core is located in the inner pump barrel 2 and the jet pump barrel 10, a working annular cavity is formed between the pump core tube 5 and the inner pump barrel 2 and between the pump core tube 5 and the jet pump barrel 10, and the inner pump barrel 2 and the jet pump barrel 10 form a working inner cavity.

[0028] Preferably, if Figure 2 and Figure 4 As shown, the pump core tube 5 and the inner pump barrel 2 are connected by a pump barrel reducer 4, and a second oil pipe coupling 3 is sleeved on the outer side of the pump barrel reducer 4. The second oil pipe coupling 3 can be connected to other tubular structures, and the end of the inner pump barrel 2 extending out of the pump core tube 5 can be connected to other tubular structures through the first oil pipe coupling 1.

[0029] Preferably, if Figure 2 and Figure 4 As shown, the first end of the jet pump barrel 10 forms a first docking platform, and the inner pump barrel 2 is inserted into the first docking platform, so that the inner pump barrel 2 is excessively inserted into the jet pump barrel 10 and is affected by the pressure change in the inner pump barrel 2 and is relatively displaced with the jet pump barrel 10, thereby improving the connection stability between the jet pump barrel 10 and the inner pump barrel 2.

[0030] Specifically, Figure 4 As shown, the outer wall of the jet pump barrel 10 is formed with a plurality of pump barrel support blocks, which abut against the inner wall of the pump core tube 5. A pump barrel support block located at the bottom end of the jet pump barrel 10 is annular, thereby closing the bottom end of the working ring cavity. The pump barrel support block can improve the stability of the jet pump barrel 10, avoid the length of the produced pump core being too long and thus swinging in the pump core tube 5, and improve the stability of the produced pump core.

[0031] Specifically, Figure 3 As shown, a conversion joint 20 is sleeved on the outer side of the pump core tube 5, the conversion joint 20 is connected to a coupling 22, a screen tube joint 23 is inserted into the coupling 22, the screen tube joint 23 is connected to a screen tube 25 through a third oil pipe coupling 24, an injection pipe column 26 is arranged in the screen tube 25, and a screen tube plug 21 is arranged at the bottom end of the injection pipe column 26 and the bottom end of the screen tube 25.

[0032] Preferably, if Figure 2 and Figure 4 As shown, an inner tube fixing sleeve 19 is inserted into the bottom end of the jet pump barrel 10, thereby improving the connection stability between the jet pump barrel 10 and the pump core tube 5.

[0033] Further, such as Figure 2 and Figure 5As shown, the production pump core includes an upper fishing head 6, an upper liquid inlet bridge 7, an upper sealing cavity 8, a nozzle 11, a positioning sleeve 12, a pressurizing cavity 13, a lower sealing cavity 14, a lower liquid inlet bridge 16, a locking sleeve 17 and a lower fishing head 18. A mixing cavity is formed between the outer wall of the nozzle 11 and the positioning sleeve 12, and a fourth through hole is opened on the positioning sleeve 12; A mixing chamber is formed between the nozzle 11 and the positioning sleeve 12, and the mixing chamber is connected to the working ring chamber. The inner wall of the jet pump barrel 10 corresponding to the position of the mixing chamber is partially recessed inward to form a first buffer groove. The inner wall of the jet pump barrel 10 corresponding to the position of the mixing chamber is provided with a first through hole 1001. The inner wall of the jet pump barrel 10 corresponding to the position of the locking sleeve 17 protrudes inward to form a shoulder 1004. The locking sleeve 17 is inserted and connected to the shoulder 1004. The jet pump barrel 10 is provided with a third through hole 1003 at a position below the shoulder 1004. The jet pump barrel 10 is provided with a second through hole 1002 at a position corresponding to the lower liquid inlet bridge 16. The fourth through hole is connected to the first buffer groove and the first through hole 1001.

[0034] Specifically, Figure 2 and Figure 5 As shown, the top of the upper salvage head 6 is a frustum, which is convenient for the staff to salvage and pull the production pump core. The bottom end of the upper salvage head 6 is inserted into the upper liquid inlet bridge 7 to connect the upper salvage head 6 and the upper liquid inlet bridge 7.

[0035] Specifically, Figure 2 and Figure 5 As shown, a plurality of upper liquid inlet channels are spaced apart at the top of the upper liquid inlet bridge 7, a first channel is formed in the middle of the upper liquid inlet bridge 7, the top of the first channel is connected to the plurality of upper liquid inlet channels, and the first channel is a part of the liquid channel.

[0036] Preferably, if Figure 2 and Figure 5 As shown, the bottom end of the upper liquid inlet bridge 7 is inserted into the top end of the upper sealing cavity 8, the outer wall of the upper sealing cavity 8 is sleeved with an upper sealing rubber tube 9, the upper sealing rubber tube 9 abuts against the inner wall of the inner pump barrel 2, and a second channel is opened in the middle of the upper sealing cavity 8, and the second channel is a part of the liquid channel.

[0037] Preferably, if Figure 2 and Figure 5 As shown, the bottom end of the upper sealing rubber tube 9 is inserted into the top end of the positioning sleeve 12, the nozzle 11 abuts against the bottom end of the upper sealing rubber tube 9, the booster cavity 13 is inserted into the positioning sleeve 12, the top end of the lower sealing cavity 14 is inserted into the bottom end of the positioning sleeve 12, and the bottom end of the booster cavity 13 abuts against the top end of the lower sealing cavity 14.

[0038] Specifically, Figure 2 and Figure 5As shown, a boosting connecting groove is formed at the position of the boosting chamber 13 corresponding to the nozzle 11, and a boosting chamber channel is formed inside the boosting chamber, which is connected to the boosting connecting groove. The inner diameter of the boosting chamber channel close to the nozzle 11 is smaller than the inner diameter away from the nozzle 11, and the inner diameter of the nozzle 11 close to the boosting chamber 13 is smaller than the inner diameter away from the boosting chamber 13. Therefore, when the power fluid is sprayed into the boosting connecting groove and the mixing chamber through the nozzle 11, the pressure changes, so that negative pressure is formed in the mixing chamber, which facilitates the coalbed methane formation fluid in the screen pipe 25 to be sucked into the mixing chamber.

[0039] Preferably, if Figure 2 and Figure 5 As shown, the inner wall of the nozzle 11 forms an injection channel, which is a part of the liquid channel. The inner diameter of the injection channel near the boost chamber 13 is smaller than the inner diameter away from the boost chamber 13. The boost connecting groove and the boost chamber channel are both part of the liquid channel.

[0040] Specifically, Figure 2 and Figure 5 As shown, the outer wall of the lower sealing cavity 14 is sleeved with a lower sealing rubber tube 15, which abuts against the inner wall of the jet pump barrel 10. A third channel is opened inside the lower sealing cavity 14, and the third channel is a part of the liquid channel.

[0041] Specifically, Figure 2 and Figure 5 As shown, the top of the lower liquid inlet bridge 16 is inserted into the bottom end of the lower sealing cavity 14, a lower liquid inlet channel is opened in the middle of the lower liquid inlet bridge 16, the bottom end of the lower liquid inlet channel is in a closed state, the lower liquid inlet channel is a part of the liquid channel, and a lower liquid inlet channel is opened on the side of the lower liquid inlet bridge 16, and the lower liquid inlet channel is connected to the second through hole 1002.

[0042] Specifically, Figure 6 As shown, the locking sleeve 17 is provided with an insertion cavity 1702 , and the lower fishing head 18 is inserted into the insertion cavity 1702 . A plurality of fixing ears 1701 are provided on the side of the locking sleeve 17 , and the fixing ears 1701 are inserted into the shoulder 1004 so that the locking sleeve 17 is fixed to the pump barrel 10 of the jet pump.

[0043] Specifically, Figure 2 and Figure 5 As shown, the liquid channels are, from top to bottom, an upper liquid inlet channel, a first channel, a second channel, an injection channel, a boost connection groove, a boost chamber channel, a third channel, and a lower liquid inlet channel.

[0044] In a specific implementation case, it is necessary to perform coalbed methane drainage operations, and the power fluid enters the working inner cavity of the inner pump barrel 2, and then enters the upper liquid inlet channel, the first channel, the second channel, the injection channel, the boost connection groove and the mixing chamber. At this time, the mixing chamber is in a negative pressure state, and the coalbed methane formation fluid in the screen tube 25 enters the working inner cavity of the inner pump barrel 2, and then enters the working annular cavity through the third through hole 1003, and then enters the mixing chamber through the first through hole 1001 to mix with the working fluid to form a mixed liquid, and then the mixed liquid passes through the boost chamber channel, the third channel, the lower liquid inlet channel, and then enters the working annular cavity through the second through hole 1002 and flows upward to discharge the working annular cavity, thereby realizing water drainage and pressure reduction of the coalbed methane well.

[0045] In another specific embodiment, when the negative pressure production pump is not needed or the production pump core is blocked and needs to be replaced, the external high-pressure liquid enters the working annular cavity, and then enters the lower liquid inlet channel, the third channel, the boosting chamber channel, and the mixing chamber through the second through hole 1002. At this time, the high-pressure liquid forms an upward thrust on the nozzle 11, so that the locking sleeve 17 is separated from the shoulder 1004, and then the production pump core moves upward along the inner pump barrel 2 to separate from the inner pump barrel 2. Then the staff salvages the production pump core through the upper salvage head 6, and the production pump core can be replaced, or the inner pump barrel 2 is made conductive up and down at this time and can be used as a gas production pipeline.

[0046] The production pump core in the embodiment of the present invention can choose whether to add a working pump barrel as needed, avoiding the replacement of the entire negative pressure drainage pump and the pump pipe, improving the construction efficiency and reducing the production cost. In this application, the locking sleeve 17, the shoulder 1004 and the pump barrel support block are provided to improve the connection stability of the production pump core in the working pump barrel. Through the nozzle 11, the positioning sleeve 12 and the booster chamber 13 of the production pump core, it is convenient to change the dynamic state of the mixed liquid and facilitate the drainage operation of coalbed methane.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A negative pressure drainage pump, characterized in that: It comprises a working pump barrel and a production pump core, the working pump barrel is formed with a working annular cavity and a working inner cavity, the production pump core is detachably connected to the working inner cavity, a liquid channel and a mixing cavity are formed inside the production pump core, the top of the liquid channel is connected to the working inner cavity and the bottom is connected to the working annular cavity, the mixing cavity is connected to the working annular cavity and the liquid channel, and the bottom of the working annular cavity is connected to the working inner cavity; The working pump barrel includes a pump core tube, an inner pump barrel and a jet pump barrel. The second end of the inner pump barrel is inserted into the pump core tube. The first end of the jet pump barrel is sleeved and connected to the second end of the inner pump barrel. The production pump core is located in the inner pump barrel and the jet pump barrel. The working annular cavity is formed between the pump core tube and the inner pump barrel and between the pump core tube and the jet pump barrel. The inner pump barrel and the jet pump barrel form the working inner cavity.

2. The negative pressure drainage pump according to claim 1, characterized in that: The outer side wall of the jet pump barrel is formed with a plurality of pump barrel support blocks, the pump barrel support blocks abut against the inner side wall of the pump core tube, and a pump barrel support block located at the bottom end of the jet pump barrel is annular.

3. The negative pressure drainage pump according to claim 1, characterized in that: The production pump core comprises an upper fishing head, an upper liquid inlet bridge, an upper sealing cavity, a nozzle, a positioning sleeve, a pressurizing cavity, a lower sealing cavity, a lower liquid inlet bridge, a locking sleeve and a lower fishing head, the mixing cavity is formed between the outer side wall of the nozzle and the positioning sleeve, and a fourth through hole is opened on the positioning sleeve; A mixing chamber is formed between the nozzle and the positioning sleeve, and the mixing chamber is connected to the working ring chamber. The inner wall of the jet pump barrel is recessed inwardly at a position corresponding to the mixing chamber to form a first buffer groove. A first through hole is provided on the inner wall of the jet pump barrel at a position corresponding to the mixing chamber. The inner wall of the jet pump barrel protrudes inwardly at a position corresponding to the locking sleeve to form a shoulder. The locking sleeve is inserted and connected to the shoulder. A third through hole is provided on the jet pump barrel below the shoulder. A second through hole is provided on the jet pump barrel at a position corresponding to the lower liquid inlet bridge. The fourth through hole is connected to the first buffer groove and the first through hole.

4. The negative pressure drainage pump according to claim 3, characterized in that: The boost cavity is formed with a boost connecting groove at a position corresponding to the nozzle, and a boost cavity channel is formed inside the boost cavity. The boost cavity channel is connected to the boost connecting groove, and the inner diameter of the boost cavity channel close to the nozzle position is smaller than the inner diameter away from the nozzle position.

5. The negative pressure drainage pump according to claim 3, characterized in that: The inner diameter of the nozzle at a position close to the pressurizing cavity is smaller than the inner diameter at a position far from the pressurizing cavity.

6. The negative pressure drainage pump according to claim 3, characterized in that: A plurality of upper liquid inlet channels are spaced apart on the top of the upper liquid inlet bridge, and a first channel is formed in the middle of the upper liquid inlet bridge, and the first channel is a part of the liquid channel.

7. The negative pressure drainage pump according to claim 3, characterized in that: A lower liquid inlet channel is opened in the middle of the lower liquid inlet bridge, the bottom end of the lower liquid inlet channel is in a closed state, the lower liquid inlet channel is a part of the liquid channel, and a lower liquid inlet channel is opened on the side of the lower liquid inlet bridge, and the lower liquid inlet channel is connected to the second through hole.

8. The negative pressure drainage pump according to claim 3, characterized in that: An upper sealing rubber tube is sleeved on the outer side wall of the upper sealing cavity, and the upper sealing rubber tube abuts against the inner side wall of the inner pump barrel; The outer side wall of the lower sealing cavity is sleeved with a lower sealing rubber tube, and the lower sealing rubber tube abuts against the inner side wall of the pump barrel of the jet pump.

9. The negative pressure drainage pump according to claim 3, characterized in that: The locking sleeve is provided with an insertion cavity, the lower fishing head is inserted in the insertion cavity, and a plurality of fixing ears are provided on the side of the locking sleeve, which are inserted into the shoulder through the fixing ears so that the locking sleeve is fixed to the pump barrel of the jet pump.

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