Three-screw pump

Abstract

The invention discloses a three-screw pump, and relates to the technical field of three-screw pumps, the three-screw pump comprises a shell, a lining is connected in the shell, a first screw group and at least one second screw group are arranged in the lining, the first screw group is connected with the output end of a driving source, the first screw group and the second screw group are arranged in parallel, and the first screw group and the second screw group are arranged in parallel. A gear set is arranged between the first screw set and the second screw sets and used for transmitting rotating power of the first screw set to all the second screw sets. The design of the scheme has at least two advantages that firstly, under the same length variation, the pressure level variation of the scheme is larger, so that the length variation needing to be changed for reaching a desired pressure value is minimum; and secondly, the flow value of the pump in the scheme is not only influenced by the specification and the lead of the spiral section, but also influenced by the transmission ratio of the gear set, the adjusting means is flexible, and the flow value of the pump can be adjusted by changing the specification and the lead of the spiral section and the transmission ratio of the gear.

Description

Technical Field

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

[0002] A three-screw pump is formed by the pump body and the screw. When the driving screw rotates, it drives the driven screw that meshes with it to rotate together. The screw meshing space at one end of the suction chamber gradually increases in volume and the pressure decreases. Under the action of pressure difference, the liquid enters the meshing space. When the volume increases to the maximum and forms a sealed cavity, the liquid moves continuously along the axis in each sealed cavity until it reaches the discharge chamber. At this time, the screw meshing space at one end of the discharge chamber gradually shrinks and discharges the liquid.

[0003] In the existing double-suction three-screw pump structure, two helical segments with the same lead and opposite rotation direction are distributed along the axial direction of the driving screw. The driving screw and the driven screw, which also has two helical segments with the same lead and opposite rotation direction, are matched and installed in the bushing. At the same time, the pump body, rear cover, bearing seat, bearing, shaft seal and other components are assembled to form the existing double-suction three-screw pump structure. In existing double-suction three-screw pumps, the two helical segments on the drive screw are designed in series. Therefore, the axial length of the drive screw inevitably increases, which in turn increases the overall length of the product. This increases the footprint of the product itself and related accessories (such as the mounting base). Since the pressure rating of a screw pump is proportional to the length of the helical segments, and the screw length cannot be increased indefinitely, it can only be designed and manufactured within a certain length ratio range. Therefore, under the constraint of length dimensions, the pressure rating of existing double-suction three-screw pumps can only be limited to the low-pressure range. Summary of the Invention

[0004] The present invention aims to solve the problem that the length of existing double-suction three-screw pumps cannot be increased indefinitely, which limits the pressure rating to a lower value.

[0005] To address the aforementioned problems, this invention provides a three-screw pump, comprising a housing, with a bushing connected within the housing. The bushing houses a first screw assembly and at least one second screw assembly. The first screw assembly is connected to the output end of a drive source and is arranged in parallel with the second screw assembly. A gear set is provided between the first and second screw assemblies to transmit the rotational power of the first screw assembly to all the second screw assemblies. The bushing divides the interior of the housing into a first chamber and a second chamber. An inlet / outlet hole is provided on the housing, and the first and second chambers communicate with one of the inlet / outlet holes respectively. A connecting groove is provided at both ends of the first screw assembly along its axial direction on the bushing. The first and second chambers communicate with the interior of the bushing through corresponding connecting grooves. A first flow channel is formed between the first screw assembly and the inner wall of the bushing, and a second flow channel is formed between the second screw assembly and the bushing. The first and second flow channels connect the first and second chambers.

[0006] The three-screw pump provided by this invention has, but is not limited to, the following beneficial effects compared to the prior art: The bushing is used to mount the first and second screw sets. Power is transmitted between the first and second screw sets via gear sets, allowing the drive source output to drive only one of the first and second screw sets to achieve synchronous movement and realize the basic function of the pump. Because the bushing divides the interior of the housing into independent first and second chambers, fluid can only flow between the first and second chambers through the first and second guide channels. This flow is driven by the first and second screw sets located within the first and second chambers, enabling fluid circulation within the pump. The screw sets are divided into two parts. To further increase the pressure rating, the pressure rating can be doubled by simultaneously increasing the length of the helical sections in both screw sets. Simultaneously, the gear sets can be adjusted... The transmission ratio also allows for changes in flow rate by increasing the speed of one screw assembly while keeping the speed of another constant. Therefore, this approach overcomes the problem in traditional single-screw assembly designs where the flow rate cannot be changed after the screw assembly is machined. By altering the transmission ratio of the gear set, the flow rate can be varied. This design offers at least two advantages: firstly, for the same length change, the pressure rating variation is greater, minimizing the length change required to reach the desired pressure value; secondly, the pump's flow rate is affected not only by the screw section specifications and lead but also by the gear ratio, providing flexible adjustment. The pump's flow rate can be adjusted by changing the screw section specifications, lead, and gear ratio.

[0007] As a further aspect of the present invention: the first screw assembly includes a first main screw and a first screw meshing with the first main screw; the second screw assembly includes a second main screw and a second screw meshing with the second main screw; the first main screw, the first screw, the second main screw, and the second screw are all rotatably mounted in a bushing; the gear assembly includes a first gear fixed on the first main screw and a second gear disposed on the second main screw; the first gear and the second gear mesh; one end of the first main screw passes through the bushing and the housing and extends outside the housing; the threads disposed on the first main screw and the second main screw have opposite directions of rotation.

[0008] As a further aspect of the present invention: the gear set is used to make the rotation directions of the first main screw and the second main screw the same, and the threads on the first main screw and the second main screw have the same direction of rotation.

[0009] As a further aspect of the present invention: the first screw assembly includes a first main screw and a first screw meshing with the first main screw; the second screw assembly includes a second main screw and a second screw meshing with the second main screw; the first main screw, the first screw, the second main screw, and the second screw are all rotatably mounted in the bushing; the gear assembly includes a first gear fixed on the first main screw and a second gear disposed on the second main screw; the gear assembly also includes an intermediate gear rotatably disposed on the bushing; the intermediate gear meshes with the second gear and with the first gear; one end of the first main screw passes through the bushing and the housing and extends outside the housing.

[0010] As a further aspect of the present invention: the second gear is slidably disposed on the second main screw, and a switching mechanism is also provided inside the housing. The switching mechanism is used to fix the second gear on the second main screw at at least two different positions, so that the second gear can switch between two states of meshing and disengaging with the first gear.

[0011] As a further embodiment of the present invention: the switching mechanism includes an adjusting retaining ring, a second gear fixed to the adjusting retaining ring, a sliding hole and a first threaded hole on the adjusting retaining ring, the adjusting retaining ring being slidably disposed at one end of a second main screw through the sliding hole, a second threaded hole being provided on the second main screw near the adjusting retaining ring, the maximum inner diameter of the second threaded hole being smaller than the minimum inner diameter of the first threaded hole, the switching mechanism further includes a first limiting block and a second limiting block, the first limiting block being provided with an external thread matching the second threaded hole, the first limiting block having a blocking portion, the maximum of the blocking portion being... The outer diameter is larger than the maximum inner diameter of the first threaded hole. The second limiting block is provided with an external thread that matches the first threaded hole. A disassembly port is provided on the housing near the adjusting retaining ring. A sealing cover is detachably connected to the housing near the disassembly port. The sealing cover is used to close the side of the disassembly port facing the outside of the housing. The radial dimensions of the first limiting block and the second limiting block are both smaller than the narrowest part of the disassembly port along the same radial direction. A detachable shaft retaining ring is provided on the outer end face of the adjusting retaining ring near the first threaded hole. The second screw assembly transmits power only to the first screw assembly through a gear set.

[0012] As a further aspect of the present invention, the specifications of the helical sections on the first main screw and the second main screw are different.

[0013] As a further aspect of the present invention: the bushing is provided with a first mounting hole and a second mounting hole at both ends along the axial direction of the first main screw, and a support section is formed on both the first main screw and the second main screw. The maximum outer diameter of the support section is smaller than the outer diameter of the corresponding helical section on the first main screw / second main screw. The inner diameter of the first mounting hole is larger than the maximum outer diameter of the corresponding first main screw / second main screw, and the inner diameter of the second mounting hole matches the outer diameter of the support section on the corresponding first main screw / second main screw.

[0014] As a further aspect of the present invention: the bushing is cylindrical in shape, and a groove is formed on the end of the bushing near the liquid inlet.

[0015] As a further aspect of the present invention, the outer diameters of the first gear and the second gear are different. Attached Figure Description

[0016] The invention will now be further described with reference to the accompanying drawings.

[0017] Figure 1 This is a schematic diagram of the structure of the present invention when viewed from the front and in the dual-absorption state; Figure 2 This is a schematic diagram of the structure of the present invention when viewed from the front and in a single-absorption state; Figure 3 This is an enlarged schematic diagram of the second main screw structure in this invention; Figure 4 This is a schematic diagram of the front view of the bushing structure of the present invention; Figure 5 This is a schematic diagram of the three-dimensional structure of the bushing of the present invention; Figure 6 This is a schematic diagram of the enlarged structure of the adjusting retaining ring of the present invention; Figure 7 This is a magnified three-dimensional structural diagram of the adjusting retaining ring of the present invention; Figure 8 This is a top-view enlarged structural schematic diagram of the present invention; Figure 9 This is a schematic diagram of the structure of a double-suction three-screw pump in the existing technology.

[0018] In the diagram: 1. Housing; 11. Inlet / outlet; 12. Disassembly port; 13. Sealing cover; 2. Bushing; 21. First guide channel; 22. Second guide channel; 23. First mounting hole; 24. Second mounting hole; 25. Groove surface; 26. Connecting groove; 3. Gear set; 31. First gear; 32. Second gear; 4. First chamber; 51. First main screw; 52. First screw; 6. Second chamber; 71. Second main screw; 72. Second screw; 8. Switching mechanism; 81. Adjusting retaining ring; 811. Sliding hole; 812. First threaded hole; 813. Shaft retaining ring; 82. Second threaded hole; 83. First limiting block; 831. Blocking part; 84. Second limiting block. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings showing multiple embodiments according to this application. It should be understood that the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments described in this application without creative effort will fall within the scope of protection of this application.

[0020] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing specific embodiments only and is not intended to limit this application; the terms "comprising," "including," "having," "containing," etc., in the description, claims, and accompanying drawings of this application are open-ended terms. Therefore, "comprising," "including," or "having" refers to, for example, a method or apparatus having one or more steps or elements, but is not limited to having only these one or more elements. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0021] In the description of this invention, it should be understood that the terms "upper", "lower", "left", "right", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0022] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" 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 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 application according to the specific circumstances.

[0023] It should be emphasized that when the term "comprising / including" is used in this specification, it is used to explicitly indicate the presence of the stated feature, integer, step, or component, but does not exclude the presence or addition of one or more other features, integers, steps, parts, or groups of features, integers, steps, or parts.

[0024] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0025] like Figure 9 As shown, the existing double-suction three-screw pump has threads with opposite directions on the driving screw, which achieves liquid flow in two channels by meshing with two sets of slave screws respectively. The pressure level achieved by this structure is proportional to the length of a single meshing helical segment on the driving screw. However, the length of the driving screw cannot be increased indefinitely, thus limiting the pressure level of the pump to a small range.

[0026] This double-suction three-screw pump is used to transport oily media.

[0027] like Figure 1 , 2 As shown in Figures 4, 5, and 8, a three-screw pump includes a housing 1, a bushing 2 connected inside the housing 1, a first screw assembly and at least one second screw assembly housed within the bushing 2, the first screw assembly being connected to the output end of a drive source, the first screw assembly and the second screw assembly being arranged side by side, a gear set 3 being provided between the first screw assembly and the second screw assembly, the gear set 3 being used to transmit the rotational power of the first screw assembly to all the second screw assemblies, the bushing 2 dividing the interior of the housing 1 into a first chamber 4 and a second chamber 6, and an inlet / outlet hole being provided on the housing 1. 11. The first chamber 4 and the second chamber 6 are respectively connected to one of the inlet and outlet holes 11. The bushing 2 is provided with connecting grooves 26 at both ends along the axial direction of the first screw assembly. The first chamber 4 and the second chamber 6 are respectively connected to the inside of the bushing 2 through the corresponding connecting grooves 26. A first guide channel 21 is formed between the first screw assembly and the inner wall surface of the bushing 2, and a second guide channel 22 is formed between the second screw assembly and the bushing 2. The first guide channel 21 and the second guide channel 22 are used to connect the first chamber 4 and the second chamber 6.

[0028] In this embodiment, bushing 2 is used to install the first screw assembly and the second screw assembly. Power is transmitted between the first screw assembly and the second screw assembly via gear set 3, so that the output of the drive source only needs to drive one of the first screw assembly and the second screw assembly to drive them to move synchronously, realizing the basic function of the pump. Since bushing 2 divides the interior of housing 1 into independent first chamber 4 and second chamber 6, fluid can only flow between the first chamber 4 and the second chamber 6 through the first guide channel 21 and the second guide channel 22 within housing 1. It is driven by the first screw assembly and the second screw assembly located in the first chamber 4 and the second chamber 6, realizing the flow of fluid in the pump. The screw assembly is divided into two parts. When it is necessary to further increase the pressure level, the pressure level can be doubled by simultaneously increasing the length of the helical section in both screw assemblies. Meanwhile, by changing the transmission ratio between gear sets 3, the speed of one screw set can be increased while keeping the speed of another screw set constant, thus changing the flow rate. This solution also helps to overcome the problem in traditional single screw set solutions where the flow rate cannot be changed after the screw set is machined. By changing the transmission ratio of gear set 3, the flow rate can be changed. This design has at least two advantages: First, with the same length change, the pressure level change is greater, minimizing the length change required to reach the desired pressure value. Second, the pump flow rate in this solution is affected not only by the length of the helical section but also by the transmission ratio of gear set 3, allowing for flexible adjustment. The pump flow rate can be adjusted by changing the helical section specifications, lead, and gear transmission ratio.

[0029] In one possible implementation, in order to further increase the pressure and reduce the axial length of the screw assembly, multiple sets of second screw assemblies can be provided. The second screw assembly can be driven between adjacent second screw assemblies via gear set 3, or between first screw assemblies via gear set 3. It is understood that as the number of second screw assemblies increases, the maximum flow rate of the pump will be higher for the same screw specifications. Furthermore, as the number of second screw assemblies increases, the number of guide channels provided in bushing 2 will also increase accordingly.

[0030] like Figure 1 , 2As shown in Figure 8, optionally, the first screw assembly includes a first main screw 51 and a first screw 52 meshing with the first main screw 51, and the second screw assembly includes a second main screw 71 and a second screw 72 meshing with the second main screw 71. The first main screw 51, the first screw 52, ​​the second main screw 71, and the second screw 72 are all rotatably mounted in the bushing 2. The gear assembly 3 includes a first gear 31 fixed on the first main screw 51 and a second gear 32 disposed on the second main screw 71. The first gear 31 and the second gear 32 mesh. One end of the first main screw 51 passes through the bushing 2 and the housing 1 and extends outside the housing 1. The threads disposed on the first main screw 51 and the second main screw 71 have opposite directions of rotation.

[0031] In this embodiment, since the first main screw 51 and the second main screw 71 are meshed by the first gear 31 and the second gear 32, their rotation directions are opposite. In order to ensure that the conveying direction of the conveying medium is consistent with the flow direction in the first guide channel 21 and the second guide channel 22, it is necessary to set the thread direction of the first main screw 51 and the second main screw 71 to be opposite. The meshing of the first gear 31 and the second gear 32 helps to transmit the rotational power of the first main screw 51 to the second main screw 71, thereby realizing the same action of the two screw groups, so as to further increase the pressure value under the premise that the first main screw 51 has the same spiral section length.

[0032] Optionally, the gear set 3 is used to make the rotation direction of the first main screw 51 and the second main screw 71 the same, and the thread direction on the first main screw 51 and the second main screw 71 the same.

[0033] In this embodiment, the rotation direction of the first main screw 51 and the second main screw 71 is the same. This ensures that the external threads of the first main screw 51 and the second main screw 71 have the same direction while ensuring that the flow direction of the conveying medium is the same. This allows the first main screw 51 and the second main screw 71 to have the same specifications and shape, making them interchangeable, reducing the differences in screw types, and lowering material preparation costs.

[0034] Optionally, the first screw assembly includes a first main screw 51 and a first screw 52 meshing with the first main screw 51, and the second screw assembly includes a second main screw 71 and a second screw 72 meshing with the second main screw 71. The first main screw 51, the first screw 52, ​​the second main screw 71, and the second screw 72 are all rotatably mounted in the bushing 2. The gear set 3 includes a first gear 31 fixed on the first main screw 51 and a second gear 32 disposed on the second main screw 71. The gear set 3 also includes an intermediate gear rotatably disposed on the bushing 2. The intermediate gear meshes with the second gear 32 and with the first gear 31. One end of the first main screw 51 passes through the bushing 2 and the housing 1 and extends outside the housing 1.

[0035] In this embodiment, the gear set 3 includes a first gear 31, a second gear 32 and an intermediate gear. The intermediate gear is used to transmit power between the first gear 31 and the second gear 32, so that the rotation direction of the final second main screw 71 is the same as that of the first main screw 51. This avoids the problem of different screw types due to different rotation directions when only screws of the same specifications need to be used, and can reduce the pressure of material preparation.

[0036] like Figure 1 and 2 As shown, optionally, the second gear 32 is slidably disposed on the second main screw 71, and a switching mechanism 8 is also provided in the housing 1. The switching mechanism 8 is used to fix the second gear 32 on the second main screw 71 at at least two different positions, so that the second gear 32 can switch between two states of meshing and disengaging with the first gear 31.

[0037] In this embodiment, the switching mechanism 8 is used to make the second gear 32 slide on the corresponding second main screw 71, so as to switch between the two states of engagement and disengagement with the first gear 31. When the second gear 32 is disengaged from the first gear 31, the second screw group corresponding to the second gear 32 will not rotate, thus avoiding wear or high temperature problems caused by idling.

[0038] like Figure 1 , 2 As shown in Figures 6 and 7, optionally, the switching mechanism 8 includes an adjusting retaining ring 81, with the second gear 32 fixed to the adjusting retaining ring 81. The adjusting retaining ring 81 has a sliding hole 811 and a first threaded hole 812. The adjusting retaining ring 81 is slidably disposed at one end of the second main screw 71 through the sliding hole 811. The second main screw 71 has a second threaded hole 82 near the adjusting retaining ring 81. The maximum inner diameter of the second threaded hole 82 is smaller than the minimum inner diameter of the first threaded hole 812. The switching mechanism 8 also includes a first limiting block 83 and a second limiting block 84. The first limiting block 83 has an external thread that matches the second threaded hole 82. The first limiting block 83 has a blocking part 831. The maximum outer diameter of 31 is greater than the maximum inner diameter of the first threaded hole 812. The second limiting block 84 is provided with an external thread that matches the first threaded hole 812. A disassembly port 12 is provided on the housing 1 near the adjusting retaining ring 81. A sealing cover 13 is detachably connected to the housing 1 near the disassembly port 12. The sealing cover 13 is used to close the side of the disassembly port 12 facing the outside of the housing 1. The radial dimensions of the first limiting block 83 and the second limiting block 84 are both smaller than the narrowest part of the disassembly port 12 along the same radial direction. A detachable shaft retaining ring 813 is provided on the outer end face of the adjusting retaining ring 81 near the first threaded hole 812. The second screw assembly transmits power only to the first screw assembly through the gear set 3.

[0039] In this embodiment, the sliding hole 811 facilitates the sliding of the adjusting retaining ring 81 on the corresponding second main screw 71. The first threaded hole 812 cooperates with the second limiting block 84 to pull the adjusting retaining ring 81 on the corresponding second main screw 71 when necessary. The second threaded hole 82 on the second main screw 71 cooperates with the first limiting block 83, allowing the first limiting block 83 to press the adjusting retaining ring 81 onto the corresponding second main screw 71 through the blocking part 831, so that the second tooth... Wheel 32 cannot move, thus ensuring it is always engaged with the first gear 31. Since the first limiting block 83 needs to pass through the first threaded hole 812 and engage with the second threaded hole 82, the maximum inner diameter of the second threaded hole 82 is smaller than the minimum inner diameter of the first threaded hole 812. The radial dimensions of both the first limiting block 83 and the second limiting block 84 are smaller than the narrowest point of the disassembly port 12 along the same radial direction, facilitating the insertion and removal of the first limiting block 83 and the second limiting block 84 from the disassembly port 12. Sealing cover 1... Three limit blocks are used to close the disassembly port 12 to prevent the conveying medium from flowing out of the disassembly port 12. The first limit block 83 and the second limit block 84 are configured such that: when the second gear 32 meshes with the first gear 31, the second limit block 84 is removed, and the first limit block 83 is threaded into the second threaded hole 82 on the corresponding second main screw 71; when the second gear 32 disengages from the first gear 31, the first limit block 83 is removed, and the second limit block 84 is threaded into the first threaded hole 812 on the corresponding adjusting retaining ring 81. The second limiting block 84 is located between the housing 1 and the corresponding sealing cover 13. The shaft retaining ring 813 on the corresponding adjusting retaining ring 81 is locked to one end of the disassembly port 12. It can be understood that the shaft retaining ring 813 can only be installed on the second limiting block 84 after the second limiting block 84 is connected to the corresponding adjusting retaining ring 81 and the adjusting retaining ring 81 is pulled out from the corresponding disassembly port 12. When the shaft retaining ring 813 is pressed against the disassembly port 12, at least the corresponding second gear 32 must not be able to contact the first gear 31.

[0040] It is understood that, in this embodiment, the switching mechanism 8 can only be applied when there is at least one second screw group, and the second screw group is only driven by the first screw group through the gear group 3, while no two second screw groups can be driven by each other.

[0041] Optionally, the specifications of the helical sections on the first main screw 51 and the second main screw 71 are different.

[0042] In this embodiment, the different specifications of the helical segments can distinguish this solution from the solutions in the prior art. In the prior art, the two sets of helical segments are set on the same screw, and it is not possible to use helical segments of different specifications. The specifications here include the lead and length of the thread, which makes the three-screw pump in this solution more flexible in adjusting the flow rate.

[0043] like Figure 1-5 As shown, optionally, the bushing 2 has a first mounting hole 23 and a second mounting hole 24 respectively opened at both ends along the axial direction of the first main screw 51. A support section is formed on both the first main screw 51 and the second main screw 71. The maximum outer diameter of the support section is smaller than the outer diameter of the corresponding helical section on the first main screw 51 / second main screw 71. The inner diameter of the first mounting hole 23 is larger than the maximum outer diameter of the corresponding first main screw 51 / second main screw 71. The inner diameter of the second mounting hole 24 matches the outer diameter of the support section on the corresponding first main screw 51 / second main screw 71.

[0044] In this embodiment, by providing the first mounting hole 23 and the second mounting hole 24 to support both ends of the first main screw 51, the stability of its installation can be improved. The maximum outer diameter of the support section is limited to be smaller than the outer diameter of the corresponding helical section on the first main screw 51 / second main screw 71, which facilitates the support end to pass through the position that the corresponding helical section can pass through. Moreover, the inner diameter of the second mounting hole 24 matches the outer diameter of the support section on the corresponding first main screw 51 / second main screw 71, which facilitates the second mounting hole 24 to provide stable support for the support end.

[0045] Optionally, the bushing 2 is cylindrical in shape, and a groove surface 25 is formed on the end of the bushing 2 near the liquid inlet.

[0046] In this embodiment, the groove surface 25 is usually processed by a subtractive process, which is mainly used to increase the cross section between the bushing 2 and the corresponding inlet / outlet hole 11 while ensuring the integrity of the bushing 2, so as to facilitate the entry of the conveying medium and increase the maximum flow rate that can enter.

[0047] Optionally, the outer diameters of the first gear 31 and the second gear 32 are different.

[0048] In this embodiment, the outer diameters of the first gear 31 and the second gear 32 are different, which can be used to change the maximum pressure value of the three-screw pump. While keeping the specifications of the first and second screw groups and the input speed unchanged, the speed of the second screw group can be changed by changing the gear size, thereby also changing the flow rate of the three-screw pump, making the design of the three-screw pump in this scheme more flexible.

[0049] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A triple screw pump characterized in that, The application relates to a screw extruder, which comprises a shell (1), a bushing (2) connected in the shell (1), a first screw group and at least one second screw group arranged in the bushing (2), a driving source output end connected with the first screw group, the first screw group and the second screw group being arranged side by side, a gear group (3) arranged between the first screw group and the second screw group and used for transmitting the rotating power of the first screw group to all the second screw groups, the bushing (2) dividing the inner part of the shell (1) into a first chamber (4) and a second chamber (6), the shell (1) being provided with an inlet and outlet hole (11), the first chamber (4) and the second chamber (6) being respectively communicated with one of the inlet and outlet holes (11), the bushing (2) being provided with a communication groove (26) at the axial end of the first screw group, the first chamber (4) and the second chamber (6) being respectively communicated with the inside of the bushing (2) through the corresponding communication grooves (26), a first flow channel (21) being formed between the first screw group and the inner wall of the bushing (2), and a second flow channel (22) being formed between the second screw group and the bushing (2), the first flow channel (21) and the second flow channel (22) being used for connecting the first chamber (4) and the second chamber (6).

2. A triple screw pump according to claim 1, characterized in that The first screw group comprises a first main screw (51) and a first secondary screw (52) engaged with the first main screw (51), the second screw group comprises a second main screw (71) and a second secondary screw (72) engaged with the second main screw (71), the first main screw (51), the first secondary screw (52), the second main screw (71) and the second secondary screw (72) are all rotatably arranged in the bushing (2), the gear group (3) comprises a first gear (31) fixed on the first main screw (51) and a second gear (32) arranged on the second main screw (71), the first gear (31) and the second gear (32) are engaged, one end of the first main screw (51) penetrates through the bushing (2) and the shell (1) and extends out of the shell (1), and the threads arranged on the first main screw (51) and the second main screw (71) have opposite rotation directions.

3. A triple screw pump according to claim 1, characterized in that The gear group (3) is used for making the rotating directions of the first main screw (51) and the second main screw (71) the same, and the threads arranged on the first main screw (51) and the second main screw (71) have the same rotation direction.

4. A triple screw pump according to claim 3, characterized in that The first screw group comprises a first main screw (51) and a first secondary screw (52) engaged with the first main screw (51), the second screw group comprises a second main screw (71) and a second secondary screw (72) engaged with the second main screw (71), the first main screw (51), the first secondary screw (52), the second main screw (71) and the second secondary screw (72) are all rotatably installed in the bushing (2), the gear set (3) comprises a first gear (31) fixed on the first main screw (51) and a second gear (32) arranged on the second main screw (71), the gear set (3) further comprises an intermediate gear rotatably arranged on the bushing (2), the intermediate gear is engaged with the second gear (32), the intermediate gear is engaged with the first gear (31), and one end of the first main screw (51) penetrates through the bushing (2) and the shell (1) and extends out of the shell (1).

5. A triple screw pump according to any one of claims 2 or 4, characterized in that The second gear (32) is slidably arranged on the second main screw (71), and the shell (1) further comprises a switching mechanism (8) arranged therein, the switching mechanism (8) is used for fixing the second gear (32) at least two different positions on the second main screw (71) to switch the second gear (32) between the engagement and disengagement with the first gear (31).

6. A triple screw pump according to claim 5, characterized in that The switching mechanism (8) comprises an adjusting blocking ring (81), the second gear (32) is fixed on the adjusting blocking ring (81), the adjusting blocking ring (81) is provided with a sliding hole (811) and a first threaded hole (812), the adjusting blocking ring (81) is slidably arranged at one end of the second main screw (71) through the sliding hole (811), the second main screw (71) is provided with a second threaded hole (82) near the adjusting blocking ring (81), the maximum inner diameter of the second threaded hole (82) is smaller than the minimum inner diameter of the first threaded hole (812), the switching mechanism (8) further comprises a first limiting block (83) and a second limiting block (84), the first limiting block (83) is provided with external threads matched with the second threaded hole (82), the first limiting block (83) has a blocking portion (831), the maximum outer diameter of the blocking portion (831) is greater than the maximum inner diameter of the first threaded hole (812), the second limiting block (84) is provided with external threads matched with the first threaded hole (812), the shell (1) is provided with a dismounting opening (12) near the adjusting blocking ring (81), the shell (1) is detachably connected with a sealing cover (13) near the dismounting opening (12), the sealing cover (13) is used for closing one side of the dismounting opening (12) towards the outside of the shell (1), the radial dimensions of the first limiting block (83) and the second limiting block (84) are both smaller than the narrowest dimension of the dismounting opening (12) along the same radial direction, and the outer end face of one end of the adjusting blocking ring (81) near the first threaded hole (812) is provided with a detachable shaft blocking ring (813), and the second screw group only transmits power to the first screw group through the gear set (3).

7. A triple screw pump according to any one of claims 2 or 4, wherein The specifications of the helical sections of the first main screw (51) and the second main screw (71) are different.

8. A triple screw pump according to any one of claims 2 or 4, wherein The first mounting hole (23) and the second mounting hole (24) are respectively arranged on the bushing (2) along the axial direction of the first main screw (51), the first main screw (51) and the second main screw (71) are provided with support sections, the maximum outer diameter of the support section is smaller than the outer diameter of the corresponding spiral section of the first main screw (51) / the second main screw (71), the inner diameter of the first mounting hole (23) is greater than the maximum outer diameter of the corresponding first main screw (51) / the second main screw (71), and the inner diameter of the second mounting hole (24) matches the outer diameter of the support section of the corresponding first main screw (51) / the second main screw (71).

9. A triple screw pump according to claim 1, wherein The bushing (2) is in the shape of a cylinder, and a groove surface (25) is formed on the bushing (2) near one end of the bushing (2) where liquid enters.

10. A triple screw pump according to any one of claims 2 or 4, characterized in that The outer diameters of the first gear (31) and the second gear (32) are different.

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