Improved twin screw pump

Abstract

The application provides an improved double screw pump, and belongs to the technical field of pumps. The application solves the problem that the existing pump cannot bear greater pressure. The improved double screw pump comprises a pump shell, a cover body, a shaft body, a limiting mechanism, a first shell, a second shell and a spiral rod. In the application, the limiting mechanism has a limiting and supporting effect, so that the end of the shaft body and the cover body cannot move out of position, and when greater air pressure or hydraulic pressure is injected between the two spiral rods, the spiral rod and the inner wall of the pump body cannot be rubbed, so that the pump body cannot be stuck or the shaft body cannot be twisted.

Description

Technical Field

[0001] This invention belongs to the field of pump technology and relates to an improved twin-screw pump. Background Technology

[0002] A pump is a machine that transports or pressurizes fluids. It transfers the mechanical energy of a prime mover or other external energy to a liquid, increasing the liquid's energy. Pumps are mainly used to transport liquids or gases such as water, oil, acids and alkalis, emulsions, suspensions, and liquid metals. They can also transport liquid-gas mixtures and liquids containing suspended solids. Pumps are generally classified into three types according to their working principle: positive displacement pumps, dynamic pumps, and other types. Besides classification by working principle, they can also be classified and named according to other methods. For example, according to the driving method, they can be divided into electric pumps and water turbine pumps; according to structure, they can be divided into single-stage pumps and multi-stage pumps; according to application, they can be divided into boiler feed pumps and metering pumps; and according to the nature of the liquid being transported, they can be divided into water pumps, oil pumps, and mud pumps. Based on whether or not they have a shaft, pumps can be divided into linear pumps and traditional pumps. As a result, pumps are increasingly widely used and are very popular. However, when too much liquid or gas is filled into the pump during use, internal malfunctions can occur. In particular, if there is no limiting structure between the rotor and the pump output end, the two rotors inside the pump body will rub against the pump chamber, causing the pump to seize up. In severe cases, the pump shaft may even break. Secondly, during use, the temperature of the pump body may change, leading to uneven material conveying. Furthermore, most pump bodies do not have a structure to guide material conveying at the material inlet, resulting in unstable material conveying within the pump body. Summary of the Invention

[0003] The purpose of this invention is to address the aforementioned problems in existing technologies by proposing an improved twin-screw pump that can maintain stable material transport and withstand greater pressure.

[0004] The objective of this invention can be achieved through the following technical solution: an improved twin-screw pump, comprising: a pump housing, a cover at the end of the pump housing, a pair of shafts movably disposed inside the pump housing, the end of each shaft being movably connected to the cover via a limiting mechanism, the pump housing comprising a first housing and a second housing, the second housing being detachably connected to the first housing, a helical rod being sleeved on each shaft, the end of each helical rod near the first housing passing through the second housing and inserting into the first housing, and each limiting mechanism being positioned and connected to the end of the corresponding helical rod.

[0005] In the aforementioned improved twin-screw pump, the limiting mechanism includes a limiting sleeve located at the end of the shaft and positioning blocks located on the cover, the same number as the limiting sleeve. The limiting sleeve and the positioning blocks are movably connected. Each positioning block is provided with a positioning tube, which is inserted into the corresponding limiting sleeve. The limiting sleeve can rotate relative to the positioning tube. A movable part is provided between the positioning tube and the limiting sleeve. The shaft, the limiting sleeve, the positioning part, and the movable part are coaxially arranged.

[0006] In the aforementioned improved twin-screw pump, the limiting sleeve is provided with a partition, which divides the interior of the limiting sleeve into a concave cavity and a limiting cavity, and the outer side of the movable part abuts against the inner wall of the limiting cavity.

[0007] In the above-mentioned improved twin-screw pump, the partition plate is connected to the end of the shaft by bolts, the end of the screw rod near the limiting sleeve is provided with a convex ring, the convex ring is inserted into the concave cavity, the head of the bolt located in the limiting cavity is inserted into the positioning tube, and the head of the bolt does not contact the inner wall of the positioning tube.

[0008] In the aforementioned improved twin-screw pump, the cover is provided with an installation groove for accommodating the limiting sleeve and the positioning block, and the cover is provided with an installation plate for connecting the positioning block at the installation groove.

[0009] In the aforementioned improved twin-screw pump, the first housing has a first channel inside, the first housing has a first inner cavity inside, and the first channel surrounds the periphery of the first inner cavity.

[0010] In the aforementioned improved twin-screw pump, the side of the first housing is provided with a first inlet and a first outlet, both of which are connected to a first channel.

[0011] In the above-mentioned improved twin-screw pump, the first housing is provided with a first connecting hole and a second connecting hole at the end face near the second housing. Both the first connecting hole and the second connecting hole are connected to the first channel. The interior of the second housing is provided with a second channel and a third channel. The plane where the second channel is located is parallel to the plane where the third channel is located. The second housing is provided with a second inner cavity. The second channel and the third channel are both arranged around the periphery of the second inner cavity.

[0012] In the above-mentioned improved twin-screw pump, the end face of the second housing near the first housing is provided with a third connecting hole and a fourth connecting hole. The third connecting hole and the fourth connecting hole are both connected to the second channel. The third connecting hole is connected to the first connecting hole, and the fourth connecting hole is connected to the second connecting hole. The second channel and the third channel are connected by multiple fifth connecting holes.

[0013] In the above-mentioned improved twin-screw pump, the first housing is provided with a feed port, the feed port includes a first through hole and two second through holes arranged symmetrically with respect to the center of the feed port, the two second through holes are connected through the first through hole, the cross-sectional shape of the first through hole is rectangular, and the cross-sectional shape of the second through hole is semi-circular.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. In this invention, the limiting and supporting functions of the limiting mechanism prevent misalignment between the end of the shaft and the cover. This prevents the spiral rods from rubbing against the inner wall of the pump casing when a larger air or hydraulic pressure is applied between the two spiral rods, thus avoiding pump jamming or shaft breakage.

[0016] 2. When the pump body of the present invention is working, the two shafts simultaneously drive the corresponding screw rods to rotate. Because the limiting sleeve is connected to the corresponding shaft, the positioning block is threaded to the cover, and the positioning tube on the positioning block is connected to the limiting sleeve through a movable part, the screw rod will not move out of place between the end near the cover and the pump casing. When a larger air pressure or hydraulic pressure is injected between the two screw rods, the screw rods and the inner wall of the pump casing can be prevented from rubbing against each other, thereby preventing the pump body from jamming or the shaft from breaking.

[0017] 3. When the moving ring seat rotates relative to the stationary ring seat, coolant can be introduced into the moving ring seat through the inlet. Since the outlet is connected to the inlet, the coolant flows out through the outlet. This reduces the temperature between the moving ring seat and the stationary ring seat and also lubricates the contact surface between them.

[0018] 4. When the twin-screw pump is in operation, liquid with a preset temperature can be introduced into the first channel through the first inlet and then flow out through the first outlet, so that the temperature of the first shell and the temperature of the first inner cavity can be raised or lowered accordingly. In this way, the material in the first shell can always be kept in a liquid state, thereby ensuring that the material can flow smoothly from the first shell to the second shell.

[0019] 5. The second channel is connected to the first channel, and the third channel is connected to the second channel, so that liquid with a preset temperature will flow into the second channel and the third channel, thereby increasing or decreasing the temperature of the second shell and the second inner cavity accordingly. In this way, the material in the second shell can always be kept in a liquid state, thus ensuring that the material can flow smoothly through the second shell. Attached Figure Description

[0020] Figure 1This is a schematic diagram of the external structure of the twin-screw pump of the present invention.

[0021] Figure 2 yes Figure 1 Sectional view at AA.

[0022] Figure 3 yes Figure 2 A magnified structural diagram at point C.

[0023] Figure 4 This is a schematic diagram of the cover structure.

[0024] Figure 5 This is a schematic diagram of the limiting sleeve.

[0025] Figure 6 This is a structural schematic diagram of the limiting sleeve from another perspective.

[0026] Figure 7 This is a schematic diagram of the screw rod.

[0027] Figure 8 This is a structural diagram of the positioning block.

[0028] Figure 9 yes Figure 2 A magnified structural diagram at point B in the middle.

[0029] Figure 10 This is a schematic diagram of the stationary ring seat.

[0030] Figure 11 yes Figure 1 A schematic diagram of the structure from another perspective after the first shell has been removed.

[0031] Figure 12 This is a schematic diagram of the external structure of the first shell in Embodiment 2.

[0032] Figure 13 This is a schematic diagram of the internal structure of the first shell in Embodiment 2.

[0033] Figure 14 This is a schematic diagram of the external structure of the first shell in Embodiment 3.

[0034] Figure 15 This is a schematic diagram of the internal structure of the first shell in Embodiment 3.

[0035] Figure 16 This is a schematic diagram of the structure of the second shell in Embodiment 3.

[0036] Figure 17 yes Figure 16 A structural schematic diagram of the second shell from another perspective.

[0037] Figure 18 yes Figure 17Sectional view at EE.

[0038] Figure 19 yes Figure 17 Sectional view at FF.

[0039] Figure 20 This is a top view of the first shell. Detailed Implementation

[0040] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0041] Example 1

[0042] like Figure 1 — Figure 10 As shown, an improved twin-screw pump of the present invention includes a pump housing 100, a cover 200, a shaft 110, a limiting mechanism 300, a first housing 130, a second housing 140, and a screw rod 120.

[0043] like Figure 1 — Figure 2 and Figure 11 As shown, the pump housing 100 has a cover 200 at its end. A pair of shafts 110 are movably disposed inside the pump housing 100. The end of each shaft 110 is movably connected to the cover 200 through a limiting mechanism 300. The pump housing 100 includes a first housing 130 and a second housing 140, which are detachably connected to the first housing 130. Each shaft 110 is fitted with a spiral rod 120. The end of each spiral rod 120 near the first housing 130 passes through the second housing 140 and is inserted into the first housing 130. Each limiting mechanism 300 is positioned and connected to the end of the corresponding spiral rod 120.

[0044] The limiting and supporting functions of the limiting mechanism 300 prevent misalignment between the end of the shaft 110 and the cover 200. This prevents the screw rods 120 from rubbing against the inner wall of the pump casing when a larger air or hydraulic pressure is injected between the two screw rods 120, thus avoiding jamming of the pump body or breakage of the shaft 110.

[0045] When material enters from the top of the first housing and the improved twin-screw pump is working, the two screws 120 rotate simultaneously. Since the end of each screw 120 near the first housing 130 passes through the second housing 140 and is inserted into the first housing 130, when material is introduced into the first housing 130, the screw 120 inserted into the first housing 130 can guide the material into the second housing 140 in advance. Thus, the improved twin-screw pump delivers material more smoothly and steadily.

[0046] like Figure 2 — Figure 8 As shown, the limiting mechanism 300 includes a limiting sleeve 310 disposed at the end of the shaft 110 and positioning blocks 320 disposed on the cover 200, the same number as the limiting sleeve 310. The limiting sleeve 310 and the positioning blocks 320 are movably connected. Each positioning block 320 is provided with a positioning tube 321. The positioning tube 321 is inserted into the corresponding limiting sleeve 310. The limiting sleeve 310 can rotate relative to the positioning tube 321. A movable member 330 is provided between the positioning tube 321 and the limiting sleeve 310. The shaft 110, the limiting sleeve 310, the positioning member, and the movable member 330 are coaxially arranged. The two shafts 110 are arranged in parallel. When in operation, the two shafts 110 simultaneously drive the corresponding screw rods 120 to rotate. Because the limiting sleeve 310 is connected to the corresponding shaft 110, the positioning block 320 is threadedly connected to the cover 200, and the positioning tube 321 on the positioning block 320 is connected to the limiting sleeve 310 through the movable part 330, the screw rod 120 will not be misaligned with the pump casing at the end near the cover 200. When a larger air pressure or hydraulic pressure is injected between the two screw rods 120, the screw rod 120 and the inner wall of the pump casing will not rub against each other, thereby preventing the pump body from jamming or the shaft 110 from breaking.

[0047] The limiting sleeve 310 has an internal partition 311 that divides the interior of the limiting sleeve 310 into a concave cavity 312 and a limiting cavity 313. The outer side of the movable member 330 abuts against the inner wall of the limiting cavity 313. The partition 311 is connected to the end of the shaft 110 by a bolt 314, so that the shaft 110 can drive the limiting sleeve 310 to rotate synchronously. The end of the spiral rod 120 near the limiting sleeve 310 has a protruding ring 121, which is inserted into the concave cavity 312. The head of the bolt 314, located in the limiting cavity 313, is inserted into the positioning tube 321, and the head of the bolt 314 does not contact the inner wall of the positioning tube 321. When the shaft 110 drives the spiral rod 120 and the limiting sleeve 310 to rotate, the movable member 330 is located on the inner wall of the limiting cavity 313 and the positioning tube 321. Between the tubes 321, the limiting sleeve 310 can rotate relative to the positioning tube 321, and the limiting sleeve 310 and the positioning tube 321 remain coaxial during the rotation process. That is, the shaft 110, the limiting sleeve 310 and the positioning tube 321 are always coaxial. Furthermore, the end of the spiral rod 120 near the limiting sleeve 310 is provided with a protruding ring 121. The protruding ring 121 is inserted into the cavity 312, and the annular side of the protruding ring 121 is in contact with the inner wall of the cavity 312. In this way, it can be further ensured that the limiting sleeve 310 will not wobble relative to the end of the spiral rod 120 during the rotation of the shaft 110 driving the spiral rod 120. That is, the shaft 110, the spiral rod 120, the limiting sleeve 310 and the positioning tube 321 are always coaxial.

[0048] In this invention, the movable component 330 may be a bearing or a stacked assembly (not shown in the figure) consisting of an inner ring (not shown in the figure) and an outer ring (not shown in the figure), which can rotate relative to each other. When a bearing is used, the inner ring (not shown in the figure) of the bearing is mounted on the positioning tube 321, and the outer ring (not shown in the figure) of the bearing abuts against the inner wall of the limiting cavity 313. During operation, the outer ring rotates relative to the inner ring. When a stacked assembly is used, the inner ring is mounted on the positioning tube 321, and the outer ring abuts against the inner wall of the limiting cavity 313. During operation, the outer ring rotates relative to the inner ring.

[0049] The movable part 330 is sleeved on the positioning tube 321. The positioning tube 321 is provided with an inner retaining ring 321a to prevent the movable part 330 from falling off the positioning tube 321. The inner wall of the limiting cavity 313 is provided with an outer retaining ring 313a to prevent the movable part 330 from falling out of the limiting cavity 313. By using the inner retaining ring 321a and the outer retaining ring 313a together, the movable part 330 can be prevented from shifting between the limiting sleeve 310 and the positioning tube 321, thereby ensuring that the limiting sleeve 310 can rotate stably relative to the positioning tube 321.

[0050] The cover 200 has an installation groove 210 for accommodating the limiting sleeve 310 and the positioning block 320. The cover 200 has an installation plate 220 for connecting the positioning block 320 at the installation groove 210. During installation, the installation plate 220 needs to be threaded to the corresponding positioning block 320 so that the positioning block 320, the positioning tube 321 and the installation plate 220 form a whole. This prevents the positioning block 320 from moving out of place with the cover when the shaft 110 drives the limiting sleeve 310 to rotate. It also allows the positioning tube 321 to limit the limiting sleeve 310 from moving out of place.

[0051] like Figure 2 , Figure 9 and Figure 10 As shown, a drive unit 400 for driving the rotation of each shaft 110 is provided on one side of the pump casing. Specifically, the drive unit 400 consists of a gearbox 411 and a motor (not shown in the figure). The gearbox 411 is connected to the pump casing. One shaft 110 is movably inserted into the gearbox 411, and the other shaft 110 passes through the gearbox 411. Both shafts 110 are provided with gears 411 at the gearbox 411. The two gears 411 mesh. The motor is connected to the shaft 110 passing through the gearbox 411, so that when the motor drives the shaft 110 to rotate, the other shaft 110 can be driven to rotate through the two gears 411.

[0052] A rotating ring seat 111 and a stationary ring seat 112 are fitted onto the shaft 110. The rotating ring seat 111 is connected to the drive component 400. One end of the stationary ring seat 112 is embedded in the rotating ring seat 111 and is in contact with the rotating ring seat 111. At least two liquid inlets 111a are provided on the outer surface of the rotating ring seat 111. The inner wall of the rotating ring seat 111 is provided with multiple liquid outlets 111b communicating with the liquid inlets 111a. The liquid outlets 111b are directly opposite the rotating ring seat 111. 11 is inserted into one end of the stationary ring seat 112. When the moving ring seat 111 rotates relative to the stationary ring seat 112, coolant can be introduced into the moving ring seat 111 through the inlet 111a. Since the outlet 111b is connected to the inlet 111a, the coolant flows out through the outlet 111b. In this way, the temperature between the moving ring seat 111 and the stationary ring seat 112 can be reduced, and the contact surface between the moving ring seat 111 and the stationary ring seat 112 can also be lubricated.

[0053] like Figure 2 , Figure 9 and Figure 10 As shown, the first housing 130 is provided with a feed port 137, which can be used to feed materials or discharge materials.

[0054] like Figure 1 and Figure 20As shown, the feed port 137 is connected to the interior of the first housing, so that material can enter the first housing 130 through the feed port 137 or material located in the first inner cavity 132 can be discharged to the outside through the feed port 137.

[0055] In the prior art, most pump bodies have circular material channels. However, in this invention, the material inlet 137 includes a first through hole 137a and two second through holes 137b symmetrically arranged around the center of the material inlet 137. The two second through holes 137b are connected through the first through hole 137a. The cross-sectional shape of the first through hole 137a is rectangular, and the cross-sectional shape of the second through hole 137b is semi-circular. It can be seen that the material inlet 137 of this invention effectively increases the cross-sectional area of ​​the material inlet 137, enabling the material inlet 137 to pass through a larger volume of material and a larger quantity of material at one time, thereby achieving the effect of rapid feeding or discharging.

[0056] Example 2

[0057] like Figure 12 and Figure 13 As shown, this embodiment adds a temperature control function to the first housing 130 based on the first embodiment.

[0058] The first housing 130 has a first channel 131 inside and a first inner cavity 132 inside. The first channel 131 surrounds the outer periphery of the first inner cavity 132. The side of the first housing 130 has a first inlet 133 and a first outlet 134. The first inlet 133 and the first outlet 134 are both connected to the first channel 131. When the twin-screw pump is in operation, liquid with a preset temperature can be introduced into the first channel 131 through the first inlet 133 and then flow out through the first outlet 134. During this process, because the first channel 131 surrounds the outer periphery of the first inner cavity 132, the liquid can fully exchange heat with the first housing 130, thereby causing the temperature of the first housing 130 and the temperature of the first inner cavity 132 to rise or fall accordingly. In this way, the material in the first housing 130 can always be kept in a liquid state, thereby ensuring that the material can flow smoothly from the first housing 130 to the second housing 140.

[0059] Example 3

[0060] This embodiment adds a temperature control function to the second housing 140 based on embodiment two.

[0061] like Figure 14 — Figure 19As shown, the first housing 130 has a first connecting hole 135 and a second connecting hole 136 at the end face near the second housing 140. Both the first connecting hole 135 and the second connecting hole 136 are connected to the first channel 131. The interior of the second housing 140 has a second channel 141 and a third channel 142. The plane where the second channel 141 is located is parallel to and does not coincide with the plane where the third channel 142 is located. The end face of the second housing 140 near the first housing 130 has a third connecting hole 144 and a fourth connecting hole 145. Both the third connecting hole 144 and the fourth connecting hole 145 are connected to the second channel 141. The third connecting hole 144 is connected to the first connecting hole 135, and the fourth connecting hole 145 is connected to the second connecting hole 136. The second channel 141 and the third channel 142 are connected through multiple fifth connecting holes 146. The second housing 140 has a second inner cavity, and the second channel 141 and the third channel 142 are both arranged around the periphery of the second inner cavity.

[0062] When liquid with a preset temperature flows into the first channel 131, because the second channel 141 is connected to the first channel 131 through the third connecting hole 144 and the first connecting hole 135, and the distance between the first connecting hole 135 and the first inlet 133 is much shorter than the distance between the second connecting hole 136 and the first inlet 133, and because the liquid entering the first channel 131 from the first inlet 133 can only move in the direction of the first inlet 133, the first connecting hole 135, the second connecting hole 136, and the first outlet 134, thus... A portion of the liquid will enter the second channel 141 through the first connecting hole 135 and the third connecting hole 144, thereby raising or lowering the area around the second channel 141 to stabilize it. When the liquid passes through the fourth connecting hole 145 of the second channel 141, it will return to the first channel 131 through the fourth connecting hole 145 and the second connecting hole 136, and be discharged through the first outlet 134. Furthermore, when the liquid flows into the second channel 141, because the third channel 142 and the second channel 141 are connected by multiple fifth connecting holes... The connecting holes 146 are connected, allowing some liquid in the second channel 141 to flow into the third channel 142 through the two fifth connecting holes 146 adjacent to the third connecting hole 144. The liquid entering the third channel 142 then flows within it and is discharged back into the second channel 141 through the remaining two fifth connecting holes 146. Since the remaining two fifth connecting holes 146 are close to the fourth connecting hole 145, the liquid will enter the first channel 131 through the remaining two fifth connecting holes 146, the fourth connecting hole 145, and the second connecting hole 136, and be discharged through the first outlet 134. This completes the liquid flow process between the first housing 130 and the second housing 140, allowing the first housing 130 and the second housing 140 to maintain a constant temperature, ensuring stable material transport within the first housing 130 and the second housing 140 while maintaining their original state. Furthermore, when the temperature of the second housing 140 rises or falls, the temperature inside the second inner cavity also rises or falls accordingly.

[0063] Furthermore, since the plane where the second channel 141 is located is parallel to and does not coincide with the plane where the third channel 142 is located, the liquid can uniformly change the temperature on the second shell 140, avoiding the situation where the temperature of one end face of the second shell 140 differs from that of the other end face.

[0064] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0065] Furthermore, in this invention, descriptions involving terms such as "first," "second," and "a" are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0066] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0067] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

Claims

1. An improved twin-screw pump, comprising: A pump housing, wherein a cover is provided at the end of the pump housing, and a pair of shafts are movably disposed inside the pump housing, characterized in that the end of each shaft is movably connected to the cover by a limiting mechanism, the pump housing includes a first housing and a second housing, the second housing and the first housing are detachably connected, a helical rod is sleeved on each shaft, and the end of each helical rod near the first housing passes through the second housing and is inserted into the first housing, and each limiting mechanism is respectively positioned and connected to the end of the corresponding helical rod; The limiting mechanism includes a limiting sleeve located at the end of the shaft and a number of positioning blocks located on the cover, the same as the limiting sleeve. The limiting sleeve and the positioning blocks are movably connected. Each positioning block is provided with a positioning tube. The positioning tube is inserted into the corresponding limiting sleeve. The limiting sleeve can rotate relative to the positioning tube. A movable part is provided between the positioning tube and the limiting sleeve. The shaft, the limiting sleeve, the positioning tube, and the movable part are coaxially arranged. The first housing is provided with a feed port, which includes a first through hole and two second through holes symmetrically arranged around the center of the feed port. The two second through holes are connected through the first through hole. The cross-sectional shape of the first through hole is rectangular and the cross-sectional shape of the second through hole is semi-circular.

2. The improved twin-screw pump according to claim 1, characterized in that, The limiting sleeve has a partition inside, which divides the inside of the limiting sleeve into a concave cavity and a limiting cavity, and the outer side of the movable part abuts against the inner wall of the limiting cavity.

3. An improved twin-screw pump according to claim 2, characterized in that, The partition plate is connected to the end of the shaft by bolts. The end of the spiral rod near the limiting sleeve is provided with a convex ring. The convex ring is inserted into the concave cavity. The head of the bolt located in the limiting cavity is inserted into the positioning tube, and the head of the bolt does not contact the inner wall of the positioning tube.

4. An improved twin-screw pump according to claim 1, characterized in that, The cover has an installation groove for accommodating the limiting sleeve and the positioning block, and the cover has an installation plate for connecting the positioning block at the installation groove.

5. An improved twin-screw pump according to claim 1, characterized in that, The first housing has a first channel inside, and the first housing has a first inner cavity inside, with the first channel surrounding the outer periphery of the first inner cavity.

6. An improved twin-screw pump according to claim 5, characterized in that, The first housing has a first inlet and a first outlet on its side, and both the first inlet and the first outlet are connected to the first channel.

7. An improved twin-screw pump according to claim 5, characterized in that, The first housing has a first connecting hole and a second connecting hole at the end face near the second housing. Both the first connecting hole and the second connecting hole are connected to the first channel. The second housing has a second channel and a third channel inside. The plane where the second channel is located is parallel to the plane where the third channel is located. The second housing has a second inner cavity inside. Both the second channel and the third channel surround the outer periphery of the second inner cavity.

8. An improved twin-screw pump according to claim 7, characterized in that, The second housing has a third connecting hole and a fourth connecting hole on its end face near the first housing. The third connecting hole and the fourth connecting hole are both connected to the second channel. The third connecting hole is connected to the first connecting hole, and the fourth connecting hole is connected to the second connecting hole. The second channel and the third channel are connected by multiple fifth connecting holes.

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