A three-screw pump

Abstract

The utility model discloses a three screw rod pump relates to pump body technical field, including three screw rod pump main part, three screw rod pump main part includes pump casing and is located in the three screw rod mechanism of pump casing, is equipped with with the feed cavity and the discharge cavity that communicates with in the pump casing in the pump casing, still include reflux channel, one end of reflux channel communicates with the discharge cavity, and is equipped with flow control mechanism, to the communication opening degree between discharge cavity and reflux channel is adjusted, another end of reflux channel is equipped with reflux control mechanism and / or noise reduction control mechanism, wherein, reflux control mechanism is used to adjust the communication switch between reflux channel and feed cavity, and noise reduction control mechanism is used to adjust the communication switch between reflux channel and the inside of pump casing, can realize noise reduction function and / or flow regulation function through this three screw rod pump.

Description

Technical Field

[0001] This utility model relates to the field of pump technology, specifically to a three-screw pump. Background Technology

[0002] Among existing three-screw pump products, due to their relatively simple structure, their main function is to quantitatively pressurize and transport fluids, and they cannot undertake other extra functions, such as flow control of quantitative pumps. At the same time, if the operating conditions deviate from the basic operating conditions of the product, such as the medium containing gas or the suction height being high, the product performance will change to some extent, and in severe cases, it will be unable to meet the user's needs.

[0003] Therefore, existing three-screw pumps are prone to cavitation when operating with a large suction head or when the conveyed medium contains a certain amount of gas. This causes a sharp increase in noise and vibration, severely affecting the product's performance. Furthermore, as a positive displacement pump, the three-screw pump has a fixed flow rate. However, in the existing product structure, there is no internal flow control channel, so the flow rate cannot be adjusted and therefore cannot meet the needs of some users who require flow rate control. Utility Model Content

[0004] The purpose of this utility model is to provide a three-screw pump to solve the following technical problems:

[0005] How to add noise reduction and flow regulation functions to a three-screw pump.

[0006] The objective of this utility model can be achieved through the following technical solutions:

[0007] A three-screw pump includes a pump body, which comprises a pump housing and a three-screw mechanism disposed within the pump housing. The pump housing has an inlet chamber and an outlet chamber that communicate with the inside of the pump housing. It also includes a reflux channel, one end of which communicates with the outlet chamber and is equipped with a flow control mechanism to control the opening degree between the outlet chamber and the reflux channel. The other end of the reflux channel is equipped with a reflux control mechanism and / or a noise reduction control mechanism.

[0008] The reflux control mechanism is used to adjust the connection between the reflux channel and the feed chamber, and the noise reduction control mechanism is used to adjust the connection between the reflux channel and the inside of the pump housing.

[0009] In a further embodiment of this utility model: the pump housing includes a pump pipe and a front end cover and a rear end cover respectively connected to both ends of the pump pipe, and the rear end cover is provided with a feed inlet communicating with the pump pipe, and the connection between the feed inlet and the pump pipe forms a feed chamber; the pump pipe is provided with a discharge outlet on the end wall near the front end cover, and the connection between the discharge outlet and the pump pipe forms a discharge chamber.

[0010] In a further embodiment of this utility model: an axial channel, i.e. a return channel, is provided in the inner wall of the pump pipe on the side away from the discharge port; one end of the axial channel is connected to the feed chamber and the other end is connected to the discharge chamber.

[0011] In a further embodiment of this utility model: a first mounting hole is provided on the wall of the pump pipe, which communicates with the discharge chamber and the axial channel. The flow control mechanism is installed in the first mounting hole to control the opening degree of communication between the discharge chamber and the axial channel.

[0012] In a further embodiment of this utility model: the flow control mechanism is generally columnar in shape, including a boss at the top, a groove is provided at the top of the boss, and a notch corresponding to the axial channel is provided on the side wall of the groove; the flow control mechanism also includes a boss driving mechanism for driving the notch of the boss to move closer to or away from the axial channel.

[0013] In a further embodiment of this utility model: the first mounting hole positions include, from the inside out, hole a, hole b, and hole d, wherein hole b is connected to the axial channel, and a slide rail c parallel to the axial direction of the hole is provided on the hole wall of hole b; the boss is installed in hole a, and the boss driving mechanism includes a movable column connected to the outer end of the boss, a positioning pin is installed on the side wall of the movable column near the boss, the movable column is installed in hole b, and the positioning pin is installed in slide rail c; the other end of the movable column has an inner hole, and a flow control rod threaded through the mounting hole is connected in the inner hole.

[0014] In a further embodiment of this utility model: a second mounting hole is provided on the wall of the pump pipe, which is connected to the inside of the pump pipe and the axial channel. The noise reduction and control mechanism is installed in the second mounting hole to control the connection between the inside of the pump pipe and the axial channel.

[0015] In a further embodiment of this utility model: the second mounting hole includes, from the inside out, a hole e communicating with the inside of the pump pipe and the axial channel, a hole f communicating with the hole e coaxially, and a hole g; the noise reduction control mechanism is cylindrical in shape, with a plug filled in the hole e at its top end, and the outer end of the plug is sequentially connected to a noise reduction control rod threaded in the hole f, a noise reduction sealing rod installed in the hole g, and a noise reduction square rod.

[0016] In a further embodiment of this utility model: a third mounting hole is provided on the wall of the pump pipe, which communicates with the inside of the pump pipe and the feed chamber. The reflux control mechanism is installed in the third mounting hole to control the connection between the feed chamber and the axial channel.

[0017] In a further embodiment of this utility model: the third mounting hole includes, from the inside out, a hole h communicating with the inside of the pump pipe, a hole i coaxially communicating with hole h, and a hole j; the reflux control mechanism is cylindrical in shape, with a plug filled in hole h at its top end, and the outer end of the plug is sequentially connected to a reflux control rod threaded in hole i, a reflux sealing rod installed in hole j, and a reflux square rod.

[0018] The beneficial effects of this utility model are:

[0019] This utility model's three-screw pump adds a reflux channel, connecting one end of which to the discharge chamber. A flow control mechanism is provided to regulate the connection between the discharge chamber and the reflux channel. The other end of the reflux channel is equipped with a reflux control mechanism and / or a noise reduction control mechanism, depending on actual needs. The flow control mechanism connects the discharge chamber to the right end of the axial channel. If noise reduction is required, the reflux control mechanism closes the connection between the left end of the axial channel and the feed chamber, and the noise reduction control mechanism connects the left end of the axial channel to the inside of the pump tube. This allows the medium to enter the reflux channel through the discharge chamber and then flow back into the pump tube (the area where the three-screw mechanism transmits the medium inside the pump body), effectively reducing product noise.

[0020] If flow regulation is required, the left end of the axial channel is sealed to the inside of the pump pipe by the noise reduction regulation mechanism, and the connection between the left end of the axial channel and the feed chamber is opened by the reflux regulation mechanism. At the same time, the opening between the discharge chamber and the axial channel is controlled by the flow regulation mechanism as needed, so that a certain amount of medium flows back to the feed chamber through the axial channel, thereby effectively regulating the output flow of the discharge chamber. Attached Figure Description

[0021] The present invention will be further described below with reference to the accompanying drawings.

[0022] Figure 1 This is a schematic diagram of the structure of the three-screw pump according to Embodiment 1 of this utility model;

[0023] Figure 2 This is a cross-sectional perspective view of the three-screw pump according to Embodiment 1 of this utility model;

[0024] Figure 3 This is a cross-sectional view of the pump housing in the three-screw pump of Embodiment 1 of this utility model;

[0025] Figure 4 This is a cross-sectional view of the internal structure of the three-screw pump according to Embodiment 1 of this utility model;

[0026] Figure 5 This is a schematic diagram of the flow control mechanism in the three-screw pump of Embodiment 1 of this utility model;

[0027] Figure 6 This is an exploded view of the flow control mechanism in the three-screw pump of Embodiment 1 of this utility model;

[0028] Figure 7 This is a schematic diagram of the noise reduction and control mechanism in the three-screw pump of Embodiment 1 of this utility model;

[0029] Figure 8 This is a schematic diagram of the reflux control mechanism in the three-screw pump of Embodiment 1 of this utility model;

[0030] Figure 9 This is a structural schematic diagram of Embodiment 2 of the present invention;

[0031] Figure 10 This is a structural schematic diagram of Embodiment 3 of this utility model.

[0032] In the diagram: 100, pump pipe; 101, discharge port; 102, axial channel; 200, front end cover; 300, rear end cover; 301, feed inlet; 400, three-screw mechanism; 500, flow control mechanism; 501, boss; 502, moving column; 503, flow control rod; 504, side cover; 505, flow sealing ring; 506, hexagonal nut; 507, positioning pin; 600, noise reduction control mechanism; 601, plug; 602, noise reduction control rod; 603, noise reduction sealing rod; 604, noise reduction square rod; 700, reflux control mechanism; 701, plug; 702, reflux control rod; 703, reflux sealing rod; 704, reflux square rod. Detailed Implementation

[0033] 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 skilled in the art without creative effort are within the protection scope of the present utility model.

[0034] Example 1

[0035] Please see Figure 1 This embodiment discloses a three-screw pump, including a three-screw pump body. The three-screw pump body includes a pump housing and a three-screw mechanism 400 disposed within the pump housing. The pump housing has an inlet chamber (low-pressure chamber) and an outlet chamber (high-pressure chamber) that communicate with the inside of the pump housing. The above structures are all conventional structures of three-screw pumps in the prior art, and their specific structures are not fully described one by one.

[0036] Please see Figure 2Specifically, in this embodiment, the pump housing includes a pump tube 100 and a front end cover 200 (left end) and a rear end cover 300 (right end) respectively connected to both ends of the pump tube 100. The rear end cover 300 has an inlet 301 communicating with the pump tube 100 on its upper side, and the connection between the inlet 301 and the pump tube 100 forms an inlet chamber. The upper side of the pipe wall of the pump tube 100 near the front end cover 200 has an outlet 101, and the connection between the outlet 101 and the pump tube 100 forms an outlet chamber. The drive end of the three-screw mechanism 400 is connected to the front end cover 200, and its main screw structure (one main screw + two auxiliary screws) is located inside the pump tube 100.

[0037] Based on the structure of the existing three-screw pump, and addressing the shortcomings mentioned in the background section regarding the inability to control the flow rate of the output medium and high noise levels, the following improvements are made:

[0038] A reflux channel is added, one end of which is connected to the discharge chamber and is equipped with a flow control mechanism 500 to control the connection opening between the discharge chamber and the reflux channel; the other end of the reflux channel is equipped with a reflux control mechanism 700 and a noise reduction control mechanism 600; wherein, the reflux control mechanism 700 is used to adjust the connection switch between the reflux channel and the feed chamber, and the noise reduction control mechanism 600 is used to adjust the connection switch between the reflux channel and the inside of the pump housing.

[0039] Please see Figure 3 Specifically, in this embodiment, an axial channel 102, i.e. a return channel, is provided inside the pipe wall on the lower side of the pump pipe 100; the left end of the axial channel 102 is connected to the feed chamber, and the right end is connected to the discharge chamber.

[0040] On the lower side of the pump pipe 100, there are also a first mounting hole, a second mounting hole, and a third mounting hole, the axial direction of which is perpendicular to the axial direction of the pump pipe 100; wherein:

[0041] The first mounting holes, from the inside out, include holes a, b, and d that are coaxially connected. Hole b is connected to the right end of the axial channel 102, and a slide c parallel to the direction of the hole axis is provided on the hole wall of hole b.

[0042] The second mounting holes, from the inside out, include hole e, which communicates with the inside of the pump pipe 100 and the axial channel 102, hole f, which communicates with hole e on the same axis, and hole g.

[0043] The third mounting holes, from the inside out, include hole h which communicates with the axial channel 102 and is located on the inner side of the axial channel 102 (the side closest to the inside of the pump pipe 100), hole i which is coaxially connected with hole h, and hole j.

[0044] It should be noted that the diameter of the axial channel 102 is d, the diameter of hole position a is d1, the diameter of hole position e is d2, and the diameter of hole position h is d3. The above diameters satisfy d2 < d < d3 < d1.

[0045] Please see Figure 4 The flow control mechanism 500 is installed in the first mounting hole to control the connection opening between the discharge chamber and the axial channel 102, specifically the connection opening between hole a and the right end of the axial channel 102; the noise reduction control mechanism 600 is installed in the second mounting hole to control the connection switch between the inside of the pump pipe 100 and the axial channel 102, specifically the connection switch between hole e and the axial channel 102; the reflux control mechanism 700 is installed in the third mounting hole to control the connection switch between the feed chamber and the axial channel 102, specifically the connection switch between the left end of the axial channel 102 and the feed chamber.

[0046] Please see Figure 4-6The flow control mechanism 500 has a columnar structure, including a boss 501 at the top. A groove is formed at the top of the boss 501, and a notch corresponding to the axial channel 102 is formed on the side wall of the groove. The flow control mechanism 500 also includes a boss driving mechanism to drive the notch of the boss 501 towards or away from the axial channel 102, thereby controlling the alignment degree between the notch and the right end of the axial channel 102, and thus controlling the flow rate of water from the discharge chamber into the axial channel 102. Specifically, the boss... 501 is installed in hole a, and the outer diameter of boss 501 is the same as the inner diameter of hole a, so that boss 501 can seal hole a; the boss drive mechanism includes a moving column 502 connected in sequence to the outer end of boss 501 (the end near the outside of pump pipe 100), the moving column 502 is installed in hole b, and a positioning pin 507 is installed on the side wall of the end of moving column 502 near boss 501, the positioning pin 507 is installed in slide c; so that the moving column can only move in the vertical direction and cannot move in the horizontal direction. Rotation; A side cover 504 is installed in hole d, and the side cover 504 is fixedly installed in hole d by four sets of locking bolts. The side cover 504 has a mounting hole communicating with the first mounting hole; The outer end of the moving column 502 has an inner hole with an internal thread and a flow control rod 503. The upper end of the flow control rod 503 has an external thread that matches the internal thread of the inner hole and passes through the inner hole through a threaded connection; The diameter of the middle end is the same as the inner diameter of the mounting hole of the side cover 504, and its outer diameter is... The wall is provided with a sealing ring mounting position, and a flow sealing ring 505 is installed on the sealing ring mounting position to achieve a seal between the middle end and the side cover 504 and prevent water leakage; the lower part of the middle end is provided with external thread and a matching hexagonal nut 506 is installed; the lower end is set in the form of a square rod to facilitate the rotation of the flow control rod 503; the distance L1 between the boss 501 and the flow control rod 503, the length L2 of the slide c, and the length L3 of the boss 501 meet the requirement that L1 < L3 < L2;

[0047] In detail, when adjusting the flow control mechanism 500, first remove the hexagonal nut 506 to release the limit on the flow control rod 503. Then, rotate the square rod at the lower end of the flow control rod 503, causing the upper end of the flow control rod 503 to rotate in the inner hole of the moving column 502. Under the limiting action of the positioning pin 507, the moving column 502 can be driven to move up and down, thereby driving the boss 501 to move up / down. This allows the notch on the boss 501 to connect / close with the right end of the axial channel 102. Furthermore, the flow rate entering the axial channel 102 from the discharge area can be controlled according to the alignment and opening of the notch and the axial channel 102 based on the displacement of the boss 501, thus achieving controllable flow adjustment.

[0048] Please see Figure 4 , Figure 7The noise reduction control mechanism 600 is cylindrical in shape, with a plug 601 at its top that fills the hole e. The outer diameter of the plug 601 is the same as the inner diameter of the hole e, allowing the plug 601 to seal the hole e. The outer end of the plug 601 is sequentially connected to a noise reduction control rod 602 located in the hole f. The inner wall of the hole f has an internal thread, and the outer wall of the noise reduction control rod 602 has an external thread that matches the internal thread in the hole f; the two are threaded together. The outer end of the noise reduction control rod 602 is connected to a noise reduction sealing rod 603 installed in the hole g. The outer diameter of the noise reduction sealing rod 603 is the same as the inner diameter of the hole g. With the same diameter, the outer wall of the noise-reducing sealing rod 603 is provided with a sealing ring mounting position, in which a noise-reducing sealing ring is installed to achieve a seal between the noise-reducing sealing rod 603 and the hole g, preventing water leakage; the outer end of the noise-reducing sealing rod 603 is connected to a noise-reducing square rod 604 to facilitate the rotation of the noise-reducing adjustment rod 602; at the same time, a retaining ring mounting position is provided in the hole g, in which a retaining ring is installed outside the noise-reducing square rod 604; the distance L4 between the noise-reducing square rod 604 and the retaining ring, the length L5 of the internal thread in the hole f, and the length L6 of the plug 601 satisfy the requirement that L4 < L6 < L5.

[0049] In detail, when adjusting the noise reduction control mechanism 600, it is only necessary to rotate the noise reduction square rod 604 to drive the noise reduction control rod 602 to rotate, thereby causing the plug 601 to move up / down, and thus causing the plug 601 to enter / leave the hole e, so that the axial channel 102 and the inside of the pump pipe 100 are closed / connected, thereby achieving the purpose of controlling the connection switch between the inside of the pump pipe 100 and the axial channel 102.

[0050] Please see Figure 4 , Figure 8The reflux control mechanism 700 is cylindrical in shape, with a plug 701 at its top that fills the hole h. The outer diameter of the plug 701 is the same as the inner diameter of the hole h, allowing the plug 701 to seal the hole h. The outer end of the plug 701 is connected to a reflux control rod 702 located in the hole i. The inner wall of the hole i has an internal thread, and the outer wall of the reflux control rod 702 has an external thread that matches the internal thread in the hole i, and the two are threaded together. The outer end of the reflux control rod 702 is connected to a reflux sealing rod 703 installed in the hole j. The outer diameter of the reflux sealing rod 703 is the same as the inner diameter of the hole j. The outer wall of the return sealing rod 703 is provided with a sealing ring mounting position, in which a return sealing ring is provided to achieve a seal between the return sealing rod 703 and the hole j, so as to prevent water leakage. The outer end of the return sealing rod 703 is connected to the return square rod 704 to facilitate the rotation of the return regulating rod 702. At the same time, the hole j is provided with a retaining ring mounting position, in which a retaining ring is installed outside the return square rod 704. The distance L7 between the return square rod 704 and the retaining ring 12, the length L8 of the internal thread in the hole i, and the length L9 of the return square rod 704 meet the requirement that L7 < L9 < L8.

[0051] In detail, when adjusting the reflux control mechanism 700, it is only necessary to rotate the reflux square rod 704 to drive the reflux control rod 702 to rotate, thereby causing the plug 701 to move up / down, and thus causing the plug 701 to enter / exit the hole h, so that the axial channel 102 and the feed chamber are closed / connected, thereby achieving the purpose of controlling the connection and switching between the feed chamber and the axial channel 102.

[0052] The working principle of this embodiment: When using the three-screw pump of this embodiment, the flow control mechanism 500 connects the discharge chamber to the right end of the axial channel 102. If noise reduction is required, the reflux control mechanism 700 closes the connection between the left end of the axial channel 102 and the feed chamber, and then opens it. The noise reduction control mechanism 600 connects the left end of the axial channel 102 to the inside of the pump tube 100, allowing the medium to enter the reflux channel 102 through the discharge chamber and then flow back into the pump tube 100 (the three-screw mechanism 400 is located in the pump body). (The internal transmission area) effectively reduces product noise; if flow regulation is required, the left end of the axial channel 102 is sealed to the inside of the pump pipe 100 by the noise reduction regulation mechanism 600, and the connection between the left end of the axial channel 102 and the feed chamber is opened by the return flow regulation mechanism 700. At the same time, the opening of the connection between the discharge chamber and the axial channel is controlled by the flow regulation mechanism 500 as needed, so that a certain amount of medium flows back to the feed chamber through the axial channel 102, thereby effectively regulating the output flow of the discharge chamber.

[0053] Example 2

[0054] Please see Figure 9 This embodiment discloses a three-screw pump. The three-screw pump in this embodiment only solves the noise reduction problem. Therefore, the difference between it and the three-screw pump in embodiment 1 is that the three-screw pump in this embodiment does not have a third mounting hole and a reflux control mechanism 700, and the left end of the axial channel 102 is not connected to the feed chamber.

[0055] Example 3

[0056] Please see Figure 10 This embodiment discloses a three-screw pump. The three-screw pump in this embodiment only solves the problem of regulating the output medium flow rate. Therefore, the difference between this embodiment and the three-screw pump in embodiment 1 is that the three-screw pump in this embodiment does not have a second mounting hole and a noise reduction and regulation mechanism 600.

[0057] In the description of this utility model, it should be understood that the terms "upper," "lower," "left," and "right," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation or specific orientational structure and operation. Therefore, they should not be construed as limitations on this utility model. Furthermore, "first" and "second" are only for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "multiple" means two or more.

[0058] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0059] The above description provides a detailed account of one embodiment of the present invention. However, this description is merely a preferred embodiment and should not be construed as limiting the scope of the present invention. All equivalent variations and improvements made within the scope of the claims of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A three-screw pump, comprising a three-screw pump body, the three-screw pump body including a pump housing and a three-screw mechanism (400) disposed within the pump housing, wherein the pump housing has an inlet chamber and an outlet chamber communicating with the inside of the pump housing; characterized in that: It also includes a reflux channel, one end of which is connected to the discharge chamber and is provided with a flow control mechanism (500) to control the opening between the discharge chamber and the reflux channel; the other end of the reflux channel is provided with a reflux control mechanism (700) and / or a noise reduction control mechanism (600). The reflux control mechanism (700) is used to adjust the connection switch between the reflux channel and the feed chamber, and the noise reduction control mechanism (600) is used to adjust the connection switch between the reflux channel and the inside of the pump housing.

2. The tri-screw pump of claim 1, wherein, The pump housing includes a pump pipe (100) and a front end cover (200) and a rear end cover (300) respectively connected to both ends of the pump pipe (100). The rear end cover (300) is provided with a feed inlet (301) communicating with the pump pipe (100). The feed inlet (301) and the connection between the feed inlet (301) and the pump pipe (100) form a feed chamber. The pump pipe (100) is provided with a discharge outlet (101) on the pipe wall near the front end cover (200). The discharge outlet (101) and the connection between the discharge outlet (101) and the pump pipe (100) form a discharge chamber.

3. The tri-screw pump of claim 2, wherein, An axial channel (102), i.e. a return channel, is provided in the inner wall of the pump pipe (100) away from the discharge port (101); one end of the axial channel (102) is connected to the feed chamber and the other end is connected to the discharge chamber.

4. The tri-screw pump of claim 3, wherein, The pump pipe (100) has a first mounting hole on its wall that communicates with the discharge chamber and the axial channel (102). The flow control mechanism (500) is installed in the first mounting hole to control the opening degree of communication between the discharge chamber and the axial channel (102).

5. The tri-screw pump of claim 4, wherein, The flow control mechanism (500) is generally columnar in shape, including a boss (501) at the top. The top of the boss (501) has a groove, and the side wall of the groove has a notch corresponding to the axial channel (102). The flow control mechanism (500) also includes a boss driving mechanism to drive the notch of the boss (501) to move closer to or away from the axial channel (102).

6. The tri-screw pump of claim 5, wherein, The first mounting holes include holes a, b, and d from the inside out. Hole b is connected to the axial channel (102), and a slide c parallel to the hole axis is provided on the hole wall of hole b. The boss (501) is installed in hole a. The boss driving mechanism includes a moving column (502) connected to the outer end of the boss (501). A positioning pin (507) is installed on the side wall of the moving column (502) near the boss (501). The moving column (502) is installed in hole b, and the positioning pin (507) is installed in slide c. The other end of the moving column (502) is provided with an inner hole, and a flow control rod (503) threaded through the mounting hole is connected in the inner hole.

7. The tri-screw pump of claim 3, wherein, The pump pipe (100) has a second mounting hole on its wall that communicates with the inside of the pump pipe (100) and the axial channel (102). The noise reduction control mechanism (600) is installed in the second mounting hole to control the connection between the inside of the pump pipe (100) and the axial channel (102).

8. The tri-screw pump of claim 7, wherein, The second mounting hole includes, from the inside out, a hole e that communicates with the inside of the pump pipe (100) and the axial channel (102), a hole f that communicates with the hole e coaxially, and a hole g; the noise reduction control mechanism (600) is cylindrical in shape, and its top end is provided with a plug (601) filled in the hole e. The outer end of the plug (601) is connected in sequence to a noise reduction control rod (602) threaded in the hole f, a noise reduction sealing rod (603) installed in the hole g, and a noise reduction square rod (604).

9. The tri-screw pump of claim 3, wherein, The pump pipe (100) has a third mounting hole on its wall that communicates with the inside of the pump pipe (100) and the feed chamber. The reflux control mechanism (700) is installed in the third mounting hole to control the connection between the feed chamber and the axial channel (102).

10. The tri-screw pump of claim 9, wherein, The third mounting hole, from the inside out, includes a hole h that communicates with the inside of the pump pipe (100), a hole i that communicates coaxially with hole h, and a hole j; the reflux control mechanism (700) is cylindrical in shape, and its top end is provided with a plug (701) filled in hole h. The outer end of the plug (701) is connected in sequence to a reflux control rod (702) threaded in hole i, a reflux sealing rod (703) installed in hole j, and a reflux square rod (704).

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