High-temperature-resistant leak-free double screw pump

Abstract

The application discloses a high-temperature-resistant and leakage-free double screw pump, which comprises a pump main body part, a power input part and a thrust support part; the pump main body part comprises a pump shell and a pair of pump screws; the pair of pump screws are engaged and adapted to a double screw cavity in the pump shell; the shafts at both ends of each pump screw are respectively installed at the end of the rear side of an inflow cavity and the end of the front side of an outflow cavity through sliding bearings; the two pump screws are limited in the axial direction through a limiting assembly; the power input part is installed at the front end of the pump main body part; the driving shaft of the power input part is in transmission connection with the shaft at the front end of one pump screw through a magnetic coupling; the thrust support part comprises an extended shaft sleeve and a thrust bearing chamber; the shaft at the rear end of one pump screw penetrates into the thrust bearing chamber through the extended shaft sleeve and is installed in the thrust bearing chamber through a thrust bearing. The application has the advantages of high-temperature resistance, stable operation under high and low viscosity, long service life and no leakage and no risk.

Description

Technical Field

[0001] This invention relates to the field of delivery pump technology, and specifically to a high-temperature resistant, leak-free twin-screw pump. Background Technology

[0002] The transport of high-temperature fluids has always been a dangerous and critical issue in the pump industry. Typical examples include heat transfer oils used in the fine chemical industry and bottom coolants containing gases in the petrochemical industry. When the medium viscosity is relatively low (below 50 cst), centrifugal pumps with extended shafts or canned motor pumps are typically used. However, in situations involving low-temperature pump start-up, the performance curve of a centrifugal pump needs to be recalibrated for every 20 cst increase in viscosity. Taking Therminol 66 heat transfer oil, which has the widest application range, as an example, its viscosity-temperature curve is as follows:

[0003]

[0004] Centrifugal pump impeller-type heat transfer oil pumps can hardly work or have extremely low efficiency when the medium temperature is below 16℃. The pump efficiency will gradually recover when the medium temperature is above 27℃, and it will be close to the normal efficiency curve when the temperature rises to 93℃.

[0005] Three-screw pumps are typically the first choice for conveying lubricating oil, but due to their cycloidal screw structure and cantilever support, they are prone to screw seizure when the medium viscosity is low (below 3.8 cst). Even when conveying heat transfer oil, they can only operate for extended periods below 100°C. Even high-precision screw pumps cannot operate for long periods at low viscosity. Their cantilever screw structure prevents the use of extended shafts and bearing insulation designs, making the bearings unsuitable for prolonged operation at high temperatures. Ceramic bearings have weak axial force resistance and are easily broken and unstable under vibration. Even as a sealed oil pump in a centrifugal heat transfer oil pump system, they cannot maintain operation at high-temperature liquids for extended periods; the maximum operating temperature for heat transfer oil media in imported three-screw pumps is 180°C.

[0006] Gear-driven thermal oil pumps are a more economical option, but they operate at a low viscosity of 1.1 cst and typically have a lifespan of only one year. Even pumps from Swiss-made brands will not last more than three years.

[0007] Therefore, in response to the industry's challenges, there is an urgent need to develop a pump that can withstand high temperatures, operate stably under both high and low viscosity conditions, has a long service life, and is leak-free and risk-free. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides a high-temperature resistant, leak-free twin-screw pump that can operate stably under high and low viscosity conditions, has a long service life, and is leak-free and risk-free.

[0009] This invention provides a high-temperature resistant, leak-free twin-screw pump, comprising:

[0010] The pump body includes a pump housing and a pair of pump screws. The pump housing has an inlet chamber, an outlet chamber located in front of the inlet chamber, and a twin-screw chamber extending in the front-rear direction and communicating with the inlet chamber and the outlet chamber at both ends, respectively. The pump housing has an inlet port communicating with the inlet chamber and an outlet port communicating with the outlet chamber. The pair of pump screws mesh and are adapted to the twin-screw chamber. The shafts at both ends of each pump screw are respectively installed at the rear end of the inlet chamber and the front end of the outlet chamber through sliding bearings. The two pump screws are axially limited by a limiting component.

[0011] The power input section includes a coupling housing, an isolation cover, an inner magnetic rotor, an outer magnetic rotor, a bearing housing, and a drive shaft. The coupling housing is fixed to the front end of the pump housing. The isolation cover is disposed inside the coupling housing and sealed and fixed to the front end of the coupling housing. The inner magnetic rotor is coaxially disposed inside the isolation cover, and the outer magnetic rotor is coaxially disposed outside the isolation cover. The shaft of the pump screw at the front end passes through the isolation cover and is coaxially and fixedly connected to the inner magnetic rotor. The bearing housing is fixed to the front end of the coupling housing. A heat insulation mechanism is provided between the bearing housing and the coupling housing. The drive shaft is mounted in the bearing housing through a rolling bearing. The rear end of the drive shaft extends into the coupling housing and is coaxially and fixedly connected to the outer magnetic rotor.

[0012] The thrust support portion includes an extended bushing and a thrust bearing chamber. The extended bushing is fixed to the rear end of the pump housing, and the thrust bearing chamber is fixed to the rear end of the extended bushing. The shaft of the pump screw at the rear end passes through the extended bushing into the thrust bearing chamber and is installed in the thrust bearing chamber through the thrust bearing.

[0013] Furthermore, the limiting component includes positioning wheels and positioning wheel grooves respectively disposed on the shafts of the two pump screws, with the positioning wheels positioned within the positioning wheel grooves.

[0014] Furthermore, the pump housing is provided with a positioning wheel cavity located behind the inlet cavity, and the positioning wheels and positioning wheel grooves outside the shafts of the two pump screws are located in the positioning wheel cavity. The side wall of the pump housing is provided with a hydraulic balance channel connecting the outlet cavity and the positioning wheel cavity.

[0015] Furthermore, a front end cover is provided between the pump housing and the coupling housing. The front end cover is fixed to the front end of the pump housing by bolts. A first flange ring is provided on the outer edge of the rear end of the coupling housing, and a second flange ring is provided on the outer edge of the rear end of the isolation cover. The first flange ring and the second flange ring are respectively fixed to the front side of the front end cover by bolts.

[0016] Furthermore, the heat insulation mechanism includes a heat insulation ring and a heat dissipation impeller. The heat insulation ring is fixed between the coupling housing and the bearing seat. Multiple air outlets are spaced apart along the circumferential direction on the heat insulation ring. Multiple air inlets connecting the outside of the bearing seat and the inside of the heat insulation ring are spaced apart along the circumferential direction on the outer edge of the bearing seat. The heat dissipation impeller is located inside the heat insulation ring and is coaxially fixed outside the drive shaft.

[0017] Furthermore, the bearing housing has a tapered expansion ring at its front end and a third flange ring located on the outer edge of the tapered expansion ring. Each of the air inlets is distributed on the tapered expansion ring. The third flange ring, the heat insulation ring, and the front end of the coupling housing are fixed together by bolts.

[0018] Furthermore, the front end of the extended bushing is provided with a rear end cover, which is fixed to the rear end of the pump housing by bolts, and a reinforcing rib is fixed between the rear end cover and the thrust bearing chamber and surrounding the extended bushing.

[0019] Furthermore, the outer periphery of the thrust bearing chamber is provided with heat dissipation fins.

[0020] Furthermore, the outer periphery of the thrust bearing chamber is provided with a water-cooled jacket, and the two opposite sides of the thrust bearing chamber are provided with a coolant inlet and a coolant outlet respectively connected to the water-cooled jacket.

[0021] Furthermore, a first wear-resistant component is fixed to the rear end of the pump screw shaft installed in the thrust bearing chamber via the thrust bearing, and a second wear-resistant component is fixed in the thrust bearing chamber near the rear of the first wear-resistant component.

[0022] The beneficial effects of this invention are reflected in:

[0023] The drive shaft of this invention is connected to an external power unit. When the power unit drives the drive shaft to rotate, the drive shaft can drive the inner magnetic rotor to rotate through the outer magnetic rotor, thereby driving a pump screw connected to it to rotate. The rotation of one pump screw can drive the rotation of another pump screw meshing with it. When the two pump screws rotate, the fluid in the inlet chamber can be forced into the outlet chamber to realize the fluid transportation.

[0024] The drive shaft and the pump screw are driven by a magnetic coupling consisting of an isolation cover, an inner magnetic rotor, and an outer magnetic rotor. The drive end of the pump body is completely sealed by the isolation cover, which can achieve complete leak-free operation while meeting the drive requirements.

[0025] Traditional magnetic couplings suffer from significant stress on rolling bearings due to the high temperature of the conveyed medium. The rolling bearing temperature often approaches the medium temperature, resulting in a short lifespan and easy damage, potentially leading to overall equipment failure. This invention addresses this issue by incorporating a heat insulation mechanism between the bearing housing and the coupling casing. This reduces the heat transferred from the coupling casing to the bearing housing, thereby lowering the operating temperature of the rolling bearing and resolving the problem of high rolling bearing temperature at the drive end.

[0026] Conventional rolling bearings are metal ball bearings, which can provide axial thrust but are not resistant to high temperatures. Sliding bearings have strong high-temperature resistance but cannot provide axial thrust. However, the pump screw of a twin-screw pump needs to withstand axial thrust, so rolling bearings are inevitably used in the internal bearings. For this reason, only ceramic ball bearings can be used when the medium temperature exceeds 200°C. When the medium viscosity is below 1 cst, ceramic rolling bearings are very easy to be damaged, which can cause the pump screw to seize up.

[0027] In this invention, each pump screw is mounted and supported at both ends by sliding bearings, ensuring stable installation within the pump housing. During operation, the axial thrust exerted by one pump screw can be transferred to the other screw via a limiting assembly. This axial thrust is then transmitted to the thrust bearing chamber via a thrust bearing at the rear end, thus meeting the axial force requirements of the pump screws. An extended bushing design between the pump housing and the thrust bearing chamber provides heat insulation, thereby reducing the operating temperature of the thrust bearing.

[0028] Therefore, all built-in bearings in this application are sliding bearings, which can meet the requirements for stable operation in high-temperature environments. The thrust bearing is externally mounted in the thrust bearing chamber and insulated from the pump housing by an extended bushing. This allows for the use of metal ball bearings in lower operating temperatures, which are less expensive, more stable than ceramic ball bearings, and more resistant to pump impacts caused by cavitation, making them less prone to damage. This design satisfies both the radial and axial force requirements of the pump screw while avoiding the need for built-in ball bearings.

[0029] Both the power input section and the thrust support section of this invention adopt a heat insulation design. The bearings of both the power input section and the thrust support section can be metal ball bearings. The bearing temperature is within the allowable range. Metal ball bearings are low in cost, have good strength and durability, and solve the problem of continuous and stable operation of screw pumps in the process of conveying high-temperature media, thus overcoming the industry's difficulties.

[0030] In summary, this invention has the advantages of high temperature resistance, stable operation under both high and low viscosity conditions, long service life, and no leakage or risk. Attached Figure Description

[0031] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0032] Figure 1 This is a perspective view of an embodiment of the present invention;

[0033] Figure 2 This is a top view of an embodiment of the present invention;

[0034] Figure 3 for Figure 2 AA section view;

[0035] Figure 4 This is a schematic diagram of the pump body of an embodiment of the present invention;

[0036] Figure 5 This is a schematic diagram of a pair of pump screws according to an embodiment of the present invention;

[0037] Figure 6 This is a schematic diagram of the power input section according to an embodiment of the present invention;

[0038] Figure 7 This is an exploded view of the power input section according to an embodiment of the present invention;

[0039] Figure 8 This is a schematic diagram of the thrust support portion according to an embodiment of the present invention;

[0040] Figure 9 This is an exploded view of the thrust support portion according to an embodiment of the present invention;

[0041] Figure 10 This is a schematic diagram of the thrust support portion according to another embodiment of the present invention.

[0042] In the attached diagram, 100-pump body; 110-pump housing; 111-inlet chamber; 112-outlet chamber; 113-twin screw chamber; 114-inlet; 115-outlet; 116-positioning wheel chamber; 117-hydraulic balance channel; 120-pump screw; 121-sliding bearing; 122-positioning wheel; 123-positioning wheel groove; 124-shaft; 200-power input part; 210-coupling housing; 211-first flange ring; 220-isolation cover; 221-second flange ring; 230-inner magnetic rotor; 240-outer magnetic rotor; 250-bearing seat; 25 1-Air inlet; 252-Conical expansion ring; 253-Third flange ring; 260-Drive shaft; 270-Heat insulation mechanism; 271-Heat insulation ring; 2711-Air outlet; 272-Heat dissipation impeller; 280-Rolling bearing; 290-Front end cover; 300-Thrust support part; 310-Extended bushing; 320-Thrust bearing chamber; 321-Heat dissipation fins; 322-Water cooling jacket; 3221-Coolant inlet; 3222-Coolant outlet; 330-Thrust bearing; 340-Rear end cover; 350-Reinforcing rib; 360-First wear-resistant part; 370-Second wear-resistant part. Detailed Implementation

[0043] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0044] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0045] like Figures 1-10 As shown, this embodiment of the invention provides a high-temperature resistant, leak-free twin-screw pump, including a pump body 100, a power input section 200, and a thrust support section 300.

[0046] Reference Figure 1 as well as Figures 3-5 The pump body 100 includes a pump housing 110 and a pair of pump screws 120. The pump housing 110 has an inlet chamber 111, an outlet chamber 112 located in front of the inlet chamber 111, and a twin-screw chamber 113 extending in the front-rear direction and communicating with the inlet chamber 111 and the outlet chamber 112 at both ends respectively. The pump housing 110 has an inlet port 114 communicating with the inlet chamber 111 and an outlet port 115 communicating with the outlet chamber 112. The pair of pump screws 120 mesh with each other and are adapted to the twin-screw chamber 113. The shafts 124 at both ends of each pump screw 120 are respectively installed at the rear end of the inlet chamber 111 and the front end of the outlet chamber 112 through sliding bearings 121. The two pump screws 120 are axially limited by a limiting assembly.

[0047] The purpose of "limiting the two pump screws 120 in the axial direction through a limiting assembly" is to transfer the axial force of one pump screw 120 to the other pump screw 120 without affecting the rotation of both pump screws 120. Specifically, the limiting assembly includes a positioning wheel 122 and a positioning wheel groove 123 respectively provided on the shaft 124 of the two pump screws 120, with the positioning wheel 122 confined within the positioning wheel groove 123.

[0048] Preferably, the pump housing 110 also includes a positioning wheel cavity 116 located behind the inlet cavity 111. The positioning wheels 122 and positioning wheel grooves 123 outside the shafts 124 of the two pump screws 120 are located in the positioning wheel cavity 116. The side wall of the pump housing 110 is provided with a hydraulic balance channel 117 connecting the outlet cavity 112 and the positioning wheel cavity 116. By setting the hydraulic balance channel 117, the fluid pressure of the outlet cavity 112 can be transmitted to the positioning wheel cavity 116. The fluid pressure in the positioning wheel cavity 116 will generate a forward axial thrust on the rear end of the pump screw 120 to offset part of the rearward axial thrust of the fluid on the pump screw 120 when it is working, thereby reducing the total rearward axial thrust of the pump screw 120 when it is working.

[0049] Reference Figure 1 , Figure 3 , Figure 6 and Figure 7 The power input section 200 includes a coupling housing 210, an isolation cover 220, an inner magnetic rotor 230, an outer magnetic rotor 240, a bearing housing 250, and a drive shaft 260. The coupling housing 210 is fixed to the front end of the pump housing 110. The isolation cover 220 is disposed inside the coupling housing 210 and sealed and fixed to the front end of the coupling housing 210. The inner magnetic rotor 230 is coaxially disposed inside the isolation cover 220, and the outer magnetic rotor 240 is coaxially disposed inside the isolation cover 220. In addition, the rod shaft 124 at the front end of the pump screw 120 passes through the isolation cover 220 and is coaxially and fixedly connected to the inner magnetic rotor 230. The bearing seat 250 is fixed to the front end of the coupling housing 210. A heat insulation mechanism 270 is provided between the bearing seat 250 and the coupling housing 210. The drive shaft 260 is installed in the bearing seat 250 through the rolling bearing 280. The rear end of the drive shaft 260 extends into the coupling housing 210 and is coaxially and fixedly connected to the outer magnetic rotor 240.

[0050] To facilitate the assembly between the power input part 200 and the pump body part 100, a front cover 290 is provided between the pump housing 110 and the coupling housing 210. The front cover 290 is fixed to the front end of the pump housing 110 by bolts. A first flange ring 211 is provided on the outer edge of the rear end of the coupling housing 210, and a second flange ring 221 is provided on the outer edge of the rear end of the isolation cover 220. The first flange ring 211 and the second flange ring 221 are respectively fixed to the front side of the front cover 290 by bolts. During assembly, first fix the front cover 290 to the front end of the pump housing 110 with bolts, then fix the inner magnetic rotor 230 to the rod shaft 124 of the pump screw 120 extending out of the front cover 290, then cover the inner magnetic rotor 230 with the isolation cover 220, and fix the second flange ring 221 of the isolation cover 220 to the front cover 290 with bolts, and finally put the outer magnetic rotor 240 on the isolation cover 220, and fix the first flange ring 211 of the coupling housing 210 to the front cover 290 with bolts.

[0051] The heat insulation mechanism 270 mainly plays a role in cooling and heat insulation between the coupling housing 210 and the bearing seat 250. Specifically, the heat insulation mechanism 270 includes a heat insulation ring 271 and a heat dissipation impeller 272. The heat insulation ring 271 is fixed between the coupling housing 210 and the bearing seat 250. Multiple air outlets 2711 are arranged circumferentially on the heat insulation ring 271. Multiple air inlets 251 connecting the outside of the bearing seat 250 and the inside of the heat insulation ring 271 are arranged circumferentially on the outer edge of the bearing seat 250. The heat dissipation impeller 272 is located inside the heat insulation ring 271 and is coaxially fixed to the outside of the drive shaft 260.

[0052] The heat insulation ring 271 itself can greatly reduce heat conduction. Furthermore, during the rotation of the drive shaft 260, it drives the cooling impeller 272 inside the heat insulation ring 271 to rotate. External air can be drawn into the heat insulation ring 271 through the air inlet 251 and discharged through the air outlet 2711 outside the heat insulation ring 271. This provides forced air cooling for the heat insulation ring 271 and the rolling bearing 280, ensuring that the rolling bearing 280 operates at a low temperature. Testing shows that the magnetic coupling with the added heat insulation mechanism 270 can further reduce the temperature of the rolling bearing 280 by more than 100 degrees Celsius under high-temperature conditions. The heat dissipation distance and airflow can be adjusted individually according to the medium temperature, thus solving the problem of high temperature in the drive end rolling bearing caused by high-temperature medium heat transfer, keeping the bearing operating below 90 degrees Celsius, and ensuring the screw pump is in optimal working condition.

[0053] To facilitate the arrangement of the air inlets 251, the front end of the bearing housing 250 is provided with a tapered expansion ring 252 and a third flange ring 253 located on the outer edge of the tapered expansion ring 252. Each air inlet 251 is distributed on the tapered expansion ring 252. The third flange ring 253, the heat insulation ring 271 and the front end of the coupling housing 210 are fixed together by bolts, which facilitates the assembly of the bearing housing 250, the heat insulation ring 271 and the coupling housing 210.

[0054] Reference Figure 1 , Figure 3 , Figure 8 and Figure 9 The thrust support portion 300 includes an extended bushing 310 and a thrust bearing chamber 320. The extended bushing 310 is fixed to the rear end of the pump housing 110, and the thrust bearing chamber 320 is fixed to the rear end of the extended bushing 310. The rod shaft 124 at the rear end of the pump screw 120 passes through the extended bushing 310 into the thrust bearing chamber 320 and is installed in the thrust bearing chamber 320 through the thrust bearing 330.

[0055] In this embodiment, the shaft 124 of the pump screw 120 is lengthened, and the thrust bearing 330 is located in an external independent chamber. An elongated narrow flow channel is formed between the shaft 124 of the pump screw 120 and the extended bushing 310. The medium in the thrust bearing chamber 320 has very little heat exchange with the medium in the pump body 100. At the same time, heat dissipation is achieved through the extended bushing 310 and the thrust bearing chamber 320, which ensures that the thrust bearing 330 operates below 90°C.

[0056] If a lower bearing operating temperature is required, heat dissipation fins 321 can be installed on the outer periphery of the thrust bearing housing 320 (e.g., Figures 1-4 as well as Figures 8-9 (As shown), to further cool the thrust bearing chamber 320 by natural air cooling, a water-cooled jacket 322 can also be installed on the outer periphery of the thrust bearing chamber 320. The thrust bearing chamber 320 has coolant inlets 3221 and coolant outlets 3222 on two opposite sides, respectively connected to the water-cooled jacket 322 (as shown). Figure 10 As shown, by introducing cooling water into the water-cooled jacket 322, the bearing chamber in the thrust bearing chamber 320 can be cooled and dissipated by water. The temperature of the thrust bearing 330 can be controlled within 70°C. If this structure is combined with the zirconia sliding bearing 121, it can handle the transportation of high-temperature media up to 350°C.

[0057] To facilitate the assembly between the thrust support portion 300 and the pump body portion 100, the front end of the extended bushing 310 is provided with a rear end cover 340. The rear end cover 340 is fixed to the rear end of the pump housing 110 by bolts. A reinforcing rib 350 is fixed between the rear end cover 340 and the thrust bearing chamber 320 and surrounds the extended bushing 310. The reinforcing rib 350 can improve the overall structural strength of the thrust support portion 300.

[0058] In one embodiment, reference is made to Figure 8 and Figure 9 The reinforcing rib 350 can be multiple heat dissipation support plates surrounding the extended bushing 310, which can strengthen the support between the rear end cover 340 and the thrust bearing chamber 320. At the same time, the heat dissipation support plates can naturally dissipate heat outward, reducing heat transfer between the rear end cover 340 and the thrust bearing chamber 320.

[0059] In another embodiment, reference is made to Figure 10 The reinforcing rib 350 can be a support cylinder surrounding the extended bushing 310, which plays a role in strengthening the support between the rear end cover 340 and the thrust bearing chamber 320. The interior of the support cylinder forms a heat insulation cavity, which can also reduce the heat transfer between the rear end cover 340 and the thrust bearing chamber 320.

[0060] In some embodiments, refer to Figure 3 and Figure 9 A first wear-resistant component 360 is fixed to the rear end of the shaft 124 of the pump screw 120, which is installed in the thrust bearing chamber 320 via the thrust bearing 330. A second wear-resistant component 370 is fixed in the thrust bearing chamber 320, located near the rear of the first wear-resistant component 360.

[0061] The first wear-resistant component 360 and the second wear-resistant component 370 can serve as protection for the thrust bearing 330. If the thrust bearing 330 fails, the contact between the first wear-resistant component 360 and the second wear-resistant component 370 can provide axial thrust support for the pump screw 120, allowing the screw pump to continue operating normally. This ensures that even if the thrust bearing 330 fails, no accidents will occur, thus providing a safety guarantee.

[0062] The drive shaft 260 of the present invention is connected to an external power unit. When the power unit drives the drive shaft 260 to rotate, the drive shaft 260 can drive the inner magnetic rotor 230 to rotate through the outer magnetic rotor 240, thereby driving a pump screw 120 connected thereto to rotate. The rotation of one pump screw 120 can drive the other pump screw 120 meshing with it to rotate. When the two pump screws 120 rotate, the fluid in the inlet chamber 111 can be forced into the outlet chamber 112 to realize the fluid transportation.

[0063] The drive shaft 260 is driven by a magnetic coupling consisting of an isolation cover 220, an inner magnetic rotor 230, and an outer magnetic rotor 240. The drive end of the pump body 100 is completely sealed by the isolation cover 220, which can achieve complete leak-free operation while meeting the drive requirements.

[0064] Traditional magnetic couplings are highly susceptible to damage from the high temperature of the conveyed medium, which significantly impacts the rolling bearing 280. The temperature of the rolling bearing 280 often approaches the temperature of the medium, leading to a short lifespan and easy damage, potentially causing overall equipment failure. This invention addresses this issue by incorporating a heat insulation mechanism 270 between the bearing housing 250 and the coupling housing 210. This reduces the heat transferred from the coupling housing 210 to the bearing housing 250, thereby lowering the operating temperature of the rolling bearing 280 and resolving the problem of high temperature at the drive end of the rolling bearing 280.

[0065] Conventional rolling bearings are metal ball bearings, which can provide axial thrust but are not resistant to high temperatures. Sliding bearings have strong high-temperature resistance but cannot provide axial thrust. However, the pump screw of a twin-screw pump needs to withstand axial thrust, so rolling bearings are inevitably used in all cases. For this reason, only ceramic ball bearings can be used when the medium temperature exceeds 200°C. When the medium viscosity is below 1 cst, ceramic rolling bearings are very easy to be damaged, which can easily cause the pump screw to seize.

[0066] Each pump screw 120 of the present invention is mounted and supported at both ends by sliding bearings 121, which ensures that the pump screw 120 is stably installed inside the pump housing 110. During operation, the axial thrust of one pump screw 120 can be transferred to the other pump screw 120 through a limiting component. The axial thrust of the pump screw 120 can also be transferred to the thrust bearing chamber 320 through the rear thrust bearing 330, thus meeting the axial force requirements of the pump screw 120. The extended bushing 310 between the pump housing 110 and the thrust bearing chamber 320 provides heat insulation, thereby reducing the operating temperature of the thrust bearing 330.

[0067] Therefore, all built-in bearings in this application are sliding bearings 121, which can meet the requirements for stable operation in high-temperature environments. The thrust bearing 330 is externally mounted inside the thrust bearing chamber 320 and is insulated from the pump housing 110 by an extended bushing 310. Since the operating environment temperature is relatively low, metal ball bearings can be used, which are less expensive, more stable than ceramic ball bearings, and more resistant to pump impact caused by cavitation, making them less prone to damage. This design satisfies the radial and axial force requirements of the pump screw 120 while avoiding the use of built-in ball bearings.

[0068] Both the power input section 200 and the thrust support section 300 of this invention adopt a heat insulation design. The bearings of both the power input section 200 and the thrust support section 300 can be metal ball bearings. The bearing temperature is within the allowable range. Metal ball bearings are low in cost, have good strength and durability, and solve the problem of continuous and stable operation of screw pumps in the process of conveying high-temperature media, thus breaking through the industry's difficulties.

[0069] In summary, this invention has the advantages of high temperature resistance, stable operation under both high and low viscosity conditions, long service life, and no leakage or risk.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A high-temperature resistant, leak-free twin-screw pump, characterized in that, include: The pump body includes a pump housing and a pair of pump screws. The pump housing has an inlet chamber, an outlet chamber located in front of the inlet chamber, and a twin-screw chamber extending in the front-rear direction and communicating with the inlet chamber and the outlet chamber at both ends, respectively. The pump housing has an inlet port communicating with the inlet chamber and an outlet port communicating with the outlet chamber. The pair of pump screws mesh and are adapted to the twin-screw chamber. The shafts at both ends of each pump screw are respectively installed at the rear end of the inlet chamber and the front end of the outlet chamber through sliding bearings. The two pump screws are axially limited by a limiting component. The power input section includes a coupling housing, an isolation cover, an inner magnetic rotor, an outer magnetic rotor, a bearing housing, and a drive shaft. The coupling housing is fixed to the front end of the pump housing. The isolation cover is disposed inside the coupling housing and sealed and fixed to the front end of the coupling housing. The inner magnetic rotor is coaxially disposed inside the isolation cover, and the outer magnetic rotor is coaxially disposed outside the isolation cover. The shaft of the pump screw at the front end passes through the isolation cover and is coaxially and fixedly connected to the inner magnetic rotor. The bearing housing is fixed to the front end of the coupling housing. A heat insulation mechanism is provided between the bearing housing and the coupling housing. The drive shaft is mounted in the bearing housing through a rolling bearing. The rear end of the drive shaft extends into the coupling housing and is coaxially and fixedly connected to the outer magnetic rotor. The thrust support portion includes an extended bushing and a thrust bearing chamber. The extended bushing is fixed to the rear end of the pump housing, and the thrust bearing chamber is fixed to the rear end of the extended bushing. The shaft of the pump screw at the rear end passes through the extended bushing into the thrust bearing chamber and is installed in the thrust bearing chamber through the thrust bearing.

2. The high-temperature resistant, leak-free twin-screw pump according to claim 1, characterized in that, The limiting component includes positioning wheels and positioning wheel grooves respectively disposed on the shafts of the two pump screws, with the positioning wheels positioned within the positioning wheel grooves.

3. The high-temperature resistant, leak-free twin-screw pump according to claim 2, characterized in that, The pump housing also has a positioning wheel cavity located behind the inlet cavity. The positioning wheels and positioning wheel grooves outside the shafts of the two pump screws are located in the positioning wheel cavity. The side wall of the pump housing has a hydraulic balance channel connecting the outlet cavity and the positioning wheel cavity.

4. The high-temperature resistant, leak-free twin-screw pump according to claim 1, characterized in that, A front cover is provided between the pump housing and the coupling housing. The front cover is fixed to the front end of the pump housing by bolts. A first flange ring is provided on the outer edge of the rear end of the coupling housing, and a second flange ring is provided on the outer edge of the rear end of the isolation cover. The first flange ring and the second flange ring are respectively fixed to the front side of the front cover by bolts.

5. The high-temperature resistant, leak-free twin-screw pump according to claim 1, characterized in that, The heat insulation mechanism includes a heat insulation ring and a heat dissipation impeller. The heat insulation ring is fixed between the coupling housing and the bearing seat. Multiple air outlets are spaced apart along the circumference of the heat insulation ring. Multiple air inlets connecting the outside of the bearing seat and the inside of the heat insulation ring are spaced apart along the circumference of the outer edge of the bearing seat. The heat dissipation impeller is located inside the heat insulation ring and is coaxially fixed outside the drive shaft.

6. The high-temperature resistant, leak-free twin-screw pump according to claim 5, characterized in that, The bearing housing has a tapered expansion ring at its front end and a third flange ring located on the outer edge of the tapered expansion ring. Each of the air inlets is distributed on the tapered expansion ring. The third flange ring, the heat insulation ring, and the front end of the coupling housing are fixed together by bolts.

7. The high-temperature resistant, leak-free twin-screw pump according to claim 1, characterized in that, The extended bushing has a rear end cover at its front end, which is fixed to the rear end of the pump housing by bolts. A reinforcing rib is fixed between the rear end cover and the thrust bearing chamber and surrounds the extended bushing.

8. The high-temperature resistant, leak-free twin-screw pump according to claim 1, characterized in that, The outer periphery of the thrust bearing chamber is provided with heat dissipation fins.

9. The high-temperature resistant, leak-free twin-screw pump according to claim 1, characterized in that, The outer periphery of the thrust bearing chamber is provided with a water-cooled jacket, and the two opposite sides of the thrust bearing chamber are provided with coolant inlets and coolant outlets respectively connected to the water-cooled jacket.

10. The high-temperature resistant, leak-free twin-screw pump according to claim 1, characterized in that, A first wear-resistant component is fixed to the rear end of the pump screw shaft installed in the thrust bearing chamber via the thrust bearing, and a second wear-resistant component is fixed in the thrust bearing chamber near the rear of the first wear-resistant component.

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