Supercritical CO2 circulating pump driven by shielding motor

Abstract

The invention discloses a supercritical CO2 circulating pump driven by a shielding motor. The supercritical CO2 circulating pump comprises a rear cover, a motor shell, a motor stator, a positioning baffle semicircular ring, a double-boss sleeve, a shielding sleeve, a sealing shell, a pump head, a rotor shaft, a motor rotor, a shaft sleeve, an auxiliary impeller, a labyrinth sealing semicircular outer sleeve, a main impeller, a bolt, a sealing ring and the like. The auxiliary impeller is additionally arranged and connected with the cooling heat exchanger through a pipeline, the CO2 temperature of the motor shell is reduced, meanwhile, a labyrinth sealing structure is adopted, mutual diffusion between high-temperature CO2 of a pump head cavity and low-temperature CO2 of the motor shell is reduced, and normal operation of the motor is guaranteed. Besides, the shielding sleeve is a metal corrugated thin-wall cylinder, shielding sleeve damage caused by thermal stress and pressure disturbance can be reduced, meanwhile, a positioning baffle semicircular ring is additionally arranged, the corrugated pipe can be changed in the area not between the motor stator and the motor rotor, it is guaranteed that gaps between the motor stator and the shielding sleeve and between the motor rotor and the shielding sleeve are not changed, and friction damage is prevented.

Description

Technical Field

[0001] The present invention relates to the field of motor pumps, and in particular to a supercritical CO2 circulation pump driven by a shielded motor. Background Art

[0002] With the in-depth research on supercritical fluid technology, supercritical CO2 extraction, supercritical CO2 dyeing, supercritical CO2 power generation and other technologies have begun to be industrialized. As one of the key equipment in supercritical CO2 technology, supercritical CO2 circulation pumps need to meet the requirements of high temperature and high pressure working conditions. However, at this stage, canned motor pumps are only suitable for low-medium pressure or low-medium temperature fluids, such as:

[0003] The utility model patent application number is 201420053642.3, and the title is "Shielded Pump for Transporting High-Pressure Fluid." Although the middle section of the stator shield is radially supported by the stator core and has a high pressure-bearing capacity, the stator shield is still designed to be very thick for the pressure of supercritical CO2. Furthermore, the patent cannot cool the high-temperature CO2 inside the shield, and cannot meet the requirements of transporting high-temperature and high-pressure supercritical CO2 fluids.

[0004] The invention patent application number is 201710154552.1, and the name is "An External Circulation Shielded Pump." It uses the gap between the shielded sleeve and the motor rotor to cool the motor. At the same time, the addition of a secondary impeller always keeps the coolant in a turbulent state, improving the cooling and heat transfer effect. However, it cannot transport high-temperature and high-pressure liquids, and there is also the problem of the shielded sleeve becoming thicker as the pressure increases.

[0005] The invention patent application number is 201910032316.1, and the name is "A high-pressure or ultra-high-pressure shielded pump". The shielding sleeve has a temperature compensation section corrugation, and the rear cover bearing assembly is welded with a pressure balancing diaphragm to prevent thermal stress from damaging the shielding sleeve. However, excessive pressure fluctuations in the shielding sleeve can cause the shielding sleeve to rub against the motor rotor or stator. The shielding sleeve is welded inside the motor housing. If damaged, the replacement cost is high. In addition, for high-temperature CO2, the shielding sleeve cannot exchange heat, affecting transmission efficiency.

[0006] The invention patent with application number 202011498859.1 and name “A Ultra-High Pressure Shielded Pump” uses an auxiliary impeller to accelerate the flow of liquid between the rotor and stator and reduce the temperature of the equipment. However, for supercritical CO2, the shielding isolation sleeve cannot withstand such high pressure. Summary of the Invention

[0007] The purpose of the present invention is to overcome the defects and shortcomings of existing canned motor pumps and provide a supercritical CO2 circulation pump driven by a canned motor.

[0008] The technical solution of the present invention is composed of a rear cover, a motor housing, a motor stator, a positioning baffle semicircular ring, a double boss sleeve, a shielding sleeve, a sealing housing, a pump head, a rotor shaft, a motor rotor, a shaft sleeve, an auxiliary impeller, a labyrinth seal semicircular outer sleeve, a bearing, a rotor shaft cover, a main impeller, bolts and a sealing ring.

[0009] Furthermore, the rear cover is a flat cover with a boss tube, a sealing groove and a sealing ring are provided on the outside of the boss tube, and a through hole matching the threaded hole of the motor housing flange is provided on the flange end face;

[0010] Furthermore, the motor housing is a cavity for installing the motor stator and shielding sleeve. Flanges are provided at both ends of the motor housing. A through hole matching the double-boss sleeve flange is provided on one end flange, a threaded hole matching the rear cover is provided on the other end flange, and a stepped hole matching the outer diameter of the positioning baffle semicircular ring is provided. A threaded hole for filling inert liquid is provided on the upper end of the motor housing, and a threaded hole for lead wire is provided on the lower end.

[0011] Furthermore, the double-boss sleeve is a flange with bosses on both ends. The flange is provided with through-holes that match the through-holes in the sealing housing flange and the motor housing flange, and the bosses are respectively equipped with sealing grooves and sealing rings. The flange also has a cooling CO2 inlet for connecting to the cooling heat exchanger pipeline. One end of the double-boss sleeve is provided with a stepped hole that matches the outer diameter of the shielding sleeve and is connected to the open end of the shielding sleeve by welding. The shielding sleeve is a corrugated thin-walled metal cylinder that isolates the motor stator and rotor.

[0012] Furthermore, the sealing shell is a cavity for installing bearings, labyrinth sealing semicircular outer sleeves, rotor shafts and main impellers. Flanges are provided at both ends of the sealing shell. A threaded hole matching the pump head is provided on one end of the flange, and a through hole matching the double-boss sleeve flange is provided on the other end of the flange. A pump CO2 outlet is provided on the end of the sealing shell close to the pump head, and a high-temperature CO2 outlet is provided on the end of the sealing shell close to the double-boss sleeve for connection to the cooling heat exchanger pipeline.

[0013] Furthermore, the pump head is a flat cover with a boss, a sealing groove and a sealing ring are provided on the outside of the boss, a through hole is provided on the flange end face that matches the threaded hole of the sealing housing flange, and the pump CO2 inlet is provided at the axis of the flat cover;

[0014] Furthermore, the rotor shaft is provided with a threaded section for fastening the motor rotor, a motor rotor section, a sleeve section, an auxiliary impeller section, a bearing section, a labyrinth seal groove, a bearing section, a rotor shaft cover section, a main impeller section and a threaded section for fastening the main impeller from one end to the other end, wherein the threaded section for fastening the motor rotor to the auxiliary impeller section is a hollow shaft.

[0015] The assembly relationship between the components of the present invention is as follows:

[0016] First, install the rotor shaft with the bearing, labyrinth seal semicircular sleeve and bearing into the inner cavity of the seal housing in sequence, and fix the rotor shaft cover to the seal housing with the hexagon socket bolts. Then, install the main impeller on the rotor shaft and fix it with nuts. Finally, install the sealing ring in the sealing groove on the pump head boss, and fix the pump head to the flange end face of the seal housing with the pump head bolt kit.

[0017] Next, install the auxiliary impeller, shaft sleeve and motor rotor on the rotor shaft in sequence and secure them with nuts;

[0018] Third, install the open end of the shielding sleeve into the stepped hole that matches the double-boss sleeve and connect them by welding; then install the sealing ring in the sealing groove of the double-boss sleeve, and then install the double-boss sleeve on the flange end face of the sealing housing;

[0019] Fourth, install the motor stator into the inner cavity of the motor housing and fix it, pass the motor lead through the lead threaded hole of the motor housing and connect it to the motor stator, fill the lead threaded hole with sealing insulation glue, and fix it with wire bolts;

[0020] Fifth, install the motor housing on the double-boss sleeve flange end face and secure it with bolts. Install the positioning baffle semi-circular ring and rubber gasket into the stepped hole in the motor housing in sequence. Then install the sealing ring in the sealing groove on the boss of the rear cover and install it on the flange end face of the motor housing. Secure the rear cover to the motor housing with the rear cover bolt kit.

[0021] Sixth, connect the CO2 inlet pipe to the pump CO2 inlet on the pump head, then connect the CO2 outlet pipe to the pump CO2 outlet on the seal housing, and connect the high-temperature CO2 outlet of the seal housing and the cooling CO2 inlet of the double-boss sleeve to the cooling heat exchanger pipeline;

[0022] Finally, fill the inert liquid through the inert liquid filling threaded hole on the motor housing. After it is full, tighten the sealing bolts to complete the installation.

[0023] The advantages of this invention include: the addition of an auxiliary impeller connected to the cooling heat exchanger piping reduces the CO2 temperature in the motor casing. The labyrinth seal structure reduces the cross-diffusion between the high-temperature CO2 in the pump head cavity and the low-temperature CO2 in the motor casing, ensuring normal motor operation. Furthermore, the shielding sleeve is a thin-walled corrugated metal cylinder, which reduces damage to the shielding sleeve caused by thermal stress and pressure disturbances. The addition of a positioning baffle semi-circular ring allows the bellows to be positioned between the non-motor stator and the motor rotor, ensuring a constant gap between the stator and rotor and the shielding sleeve, preventing friction damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0025] Figure 2 for Figure 1 A partial enlarged view of middle A;

[0026] Reference numerals:

[0027] 1. Rear cover 1-1, rear cover bolt kit 1-2, sealing ring 2, motor housing 2-1, motor stator 2-2, positioning baffle semicircular ring 2-3, rubber gasket 2-4, pressing bolt 2-5, sealing bolt 3, double boss sleeve 3-1, shielding sleeve 3-2, sealing ring 3-3, cooling CO2 inlet 3-4, sealing ring 3-5, bolt 4, sealing housing 4-1, pump CO2 outlet 4-2, high-temperature CO2 outlet 4-3, rotor shaft cover 4-4, hexagon socket bolt 5, pump head 5-1, sealing ring 5-2, pump head bolt kit 5-3, pump CO2 inlet 6, rotor shaft 6-1, nut 6-2, motor rotor 6-3, sleeve 6-4, auxiliary impeller 6-5, bearing 6-6, labyrinth seal semicircular sleeve 6-7, bearing 6-8, main impeller 6-9, nut DETAILED DESCRIPTION

[0028] The embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0029] The technical solution of the present invention is composed of a rear cover 1, a motor housing 2, a motor stator 2-1, a positioning baffle semicircular ring 2-2, a double boss sleeve 3, a shielding sleeve 3-1, a sealing housing 4, a pump head 5, a rotor shaft 6, a motor rotor 6-2, a sleeve 6-1, an auxiliary impeller 6-4, a labyrinth seal semicircular outer sleeve 6-6 and a main impeller 6-8, etc. Figure 1 and Figure 2 shown.

[0030] The rear cover 1 is a flat cover with a boss tube. The outer side of the boss tube is provided with a sealing groove and a sealing ring 1-2. The flange end face is provided with a through hole matching the threaded hole of the motor housing 2 flange.

[0031] The motor housing 2 is a cavity for mounting the motor stator 2-1 and the shielding sleeve 3-1. Flanges are provided at both ends of the motor housing 2. One end flange is provided with a through hole that matches the flange of the double-boss sleeve 3, and the other end flange is provided with a threaded hole that matches the rear cover 1. Furthermore, a stepped hole is provided that matches the outer diameter of the positioning baffle ring 2-2. A threaded hole for filling an inert liquid is provided at the upper end of the motor housing 2, and a threaded hole for a lead wire is provided at the lower end.

[0032] The double-boss sleeve 3 is a flange with bosses at both ends. The flange features through-holes that match the flange through-holes of the sealing housing 4 and the motor housing 2. The bosses are equipped with sealing grooves and sealing rings 3-2 and 3-4, respectively. The flange also features a cooling CO2 inlet 3-3 for connection to the cooling heat exchanger piping. The double-boss sleeve 3 has a stepped hole that matches the outer diameter of the shielding sleeve 3-1 and is welded to the open end of the shielding sleeve 3-1. The shielding sleeve 3-1 is a corrugated, thin-walled metal cylinder that isolates the motor stator 2-1 from the rotor 3-1.

[0033] The above-mentioned sealing shell 4 is a cavity for installing the bearing 6-5, the labyrinth sealing semicircular sleeve 6-6, the bearing 6-7, the rotor shaft 6 and the main impeller 6-8. Flanges are provided at both ends of the sealing shell 4. A threaded hole matching the pump head 5 is provided at one end of the flange, and a through hole matching the barrel flange of the double boss sleeve 3 is provided at the other end of the flange. A pump CO2 outlet 4-1 is provided at the end of the sealing shell 4 close to the pump head 5, and a high-temperature CO2 outlet 4-2 is provided at the end of the sealing shell 4 close to the double boss sleeve 5 for connecting to the cooling heat exchanger pipeline;

[0034] The pump head 5 is a flat cover with a boss, the outer side of the boss is provided with a sealing groove and a sealing ring 5-1, the flange end face is provided with a through hole matching the threaded hole of the flange of the sealing housing 4, and the pump CO2 inlet 5-3 is provided at the axis of the flat cover;

[0035] The above-mentioned rotor shaft 6 is sequentially provided with a threaded section for fastening the motor rotor 6-2, a motor rotor section 6-2, a sleeve section 6-3, an auxiliary impeller section 6-4, a bearing section 6-5, a labyrinth seal groove, a bearing section 6-7, a rotor shaft cover section 4-3, a main impeller section 6-8 and a threaded section for fastening the main impeller 6-8 from one end to the other end, wherein the threaded section for fastening the motor rotor 6-2 to the auxiliary impeller 6-4 section is a hollow shaft.

[0036] The assembly relationship between the components of the present invention is as follows:

[0037] First, install the rotor shaft 6 with the bearing 6-5, labyrinth seal semicircular sleeve 6-6 and bearing 6-7 installed into the inner cavity of the seal housing 4 in sequence, and fix the rotor shaft cover 4-3 to the seal housing 4 with the hexagon socket bolt 4-4. Then, install the main impeller 6-8 on the rotor shaft 6 and fix it with the nut 6-9. Finally, install the sealing ring 5-1 in the sealing groove on the boss of the pump head 5, and then fix the pump head 5 to the flange end face of the seal housing 4 with the pump head bolt kit 5-2.

[0038] Next, install the auxiliary impeller 6-4, the shaft sleeve 6-3 and the motor rotor 6-2 on the rotor shaft 6 in sequence and secure them with the nut 6-1;

[0039] Third, install the open end of the shielding sleeve 3-1 into the stepped hole that matches the double-boss sleeve 3 and connect them by welding; then install the sealing ring 3-2 and the sealing ring 3-4 in the sealing groove of the double-boss sleeve 3, and then install the double-boss sleeve 3 on the flange end face of the sealing housing 4;

[0040] Fourth, install the motor stator 2-1 into the inner cavity of the motor housing 2 and fix it. Pass the motor lead through the lead threaded hole of the motor housing 2 and connect it to the motor stator 2-1. Fill the lead threaded hole with sealing insulation glue and fix it with the wire pressing bolt 2-4.

[0041] Fifth, install the motor housing 2 on the flange end face of the double-boss sleeve 3 and secure it with bolts 3-5. Install the positioning baffle semicircular ring 2-2 and the rubber gasket 2-3 into the stepped hole in the motor housing 2 in sequence. Then install the sealing ring 1-2 in the sealing groove on the boss of the rear cover 1, install it on the flange end face of the motor housing 2, and secure the rear cover 1 to the motor housing 2 with the rear cover bolt kit 1-1.

[0042] Finally, fill the inert liquid through the inert liquid filling threaded hole on the motor housing 2. After it is full, tighten the sealing bolts 2-5 to complete the installation.

[0043] The working steps of the present invention are:

[0044] First, connect the CO2 inlet pipe to the pump CO2 inlet 5-3 on the pump head 5, connect the CO2 outlet pipe to the pump CO2 outlet 4-1 on the sealed housing 4, and connect the high-temperature CO2 outlet 4-2 of the sealed housing 4 and the cooling CO2 inlet 3-3 of the double-boss sleeve 3 to the cooling heat exchanger pipeline; then, fill the inert liquid through the inert liquid filling threaded hole on the motor housing 2. After it is full, tighten the sealing bolts 2-5, and then connect the motor leads to the power supply;

[0045] Secondly, open the valves in the cooling heat exchanger pipeline, then slowly open the valve of the CO2 inlet pipe 5-3, slowly fill the pump head 5, the sealing shell 4 and the shielding sleeve 3-1 cavity and the cooling heat exchanger pipeline with CO2, and finally open the valve of the CO2 outlet pipe 4-1.

[0046] Third, turn on the external power switch. This energizes the motor stator 2-1, generating a magnetic field. This magnetic field transmits power to the motor rotor 6-2, which in turn drives the main impeller 6-8 and the secondary impeller 6-4, which then begin to work and transport CO2. Simultaneously, the secondary impeller 6-4 rotates along with the rotor shaft 6. The high-temperature CO2 in the motor housing 2 is cooled by heat exchange in the cooling heat exchanger pipes, becoming low-temperature CO2. This CO2 then enters the motor housing 2 through the cooled CO2 inlet pipe 3-3 and passes through the hollow shaft section of the rotor shaft 6, continuously circulating and exchanging heat, lowering the temperature of the motor housing 2 and ensuring normal motor operation.

[0047] The present invention incorporates an auxiliary impeller connected to the cooling heat exchanger piping to reduce the CO2 temperature in the motor casing. A labyrinth seal structure also minimizes cross-diffusion between the high-temperature CO2 in the pump head cavity and the low-temperature CO2 in the motor casing, ensuring proper motor operation. Furthermore, the shielding sleeve is a thin-walled corrugated metal cylinder, which reduces damage to the shielding sleeve caused by thermal stress and pressure disturbances. The addition of a positioning baffle semi-circular ring allows the bellows to be positioned between the non-motor stator and the motor rotor, ensuring a constant gap between the stator and rotor and the shielding sleeve, preventing friction damage.

Claims

1. A supercritical CO2 circulation pump driven by a canned motor, characterized in that: It consists of a rear cover, a motor housing, a motor stator, a positioning baffle semicircular ring, a double boss sleeve, a shielding sleeve, a sealing housing, a pump head, a rotor shaft, a motor rotor, a shaft sleeve, an auxiliary impeller, a labyrinth seal semicircular outer sleeve, a main impeller, bolts and a sealing ring.

2. A supercritical CO2 circulating pump driven by a canned motor as claimed in claim 1, characterized in that: The rear cover is a flat cover with a boss tube. A sealing groove and a sealing ring are provided on the outside of the boss tube. A through hole matching the threaded hole of the motor housing flange is provided on the flange end face.

3. A supercritical CO2 circulating pump driven by a canned motor as claimed in claim 1, characterized in that: The motor housing is a cavity for installing the motor stator and shielding sleeve. Flanges are provided at both ends of the motor housing. A through hole matching the double-boss sleeve flange is provided on one end flange, a threaded hole matching the rear cover is provided on the other end flange, and a stepped hole matching the outer diameter of the positioning baffle semicircular ring is provided. A threaded hole for filling inert liquid is provided on the upper end of the motor housing, and a threaded hole for lead wire is provided on the lower end.

4. A supercritical CO2 circulating pump driven by a canned motor as claimed in claim 1, characterized in that: The double-boss sleeve is a flange with boss tubes at both ends. The flange is provided with through holes that match the through holes of the sealing shell flange and the motor shell flange. The boss tubes are respectively provided with sealing grooves and sealing rings. At the same time, the flange is provided with a cooling CO2 inlet for connecting to the cooling heat exchanger pipeline; the double-boss sleeve is provided with a stepped hole that matches the outer diameter of the shielding sleeve, and is connected to the open end of the shielding sleeve by welding; the shielding sleeve is a metal corrugated thin-walled cylinder that isolates the motor stator and the motor rotor.

5. A supercritical CO2 circulating pump driven by a canned motor as claimed in claim 1, characterized in that: The sealing shell is a cavity for installing bearings, labyrinth sealing semicircular outer sleeves, rotor shafts and main impellers. Flanges are provided at both ends of the sealing shell. A threaded hole matching the pump head is provided on one end flange, and a through hole matching the double-boss sleeve flange is provided on the other end flange. A pump CO2 outlet is provided on the end of the sealing shell close to the pump head, and a high-temperature CO2 outlet is provided on the end of the sealing shell close to the double-boss sleeve for connecting to the cooling heat exchanger pipeline.

6. A supercritical CO2 circulating pump driven by a canned motor as claimed in claim 1, characterized in that: The pump head is a flat cover with a boss, a sealing groove and a sealing ring are provided on the outside of the boss, a through hole is provided on the flange end face that matches the threaded hole of the sealing shell flange, and a pump CO2 inlet is provided on the axis of the flat cover.

7. A canned motor driven supercritical CO2 circulation pump as claimed in claim 1, characterized in that: The rotor shaft is provided with a threaded section for fastening the motor rotor, a motor rotor section, a sleeve section, an auxiliary impeller section, a bearing section, a labyrinth seal groove, a bearing section, a rotor shaft cover section, a main impeller section and a threaded section for fastening the main impeller from one end to the other end, wherein the threaded section for fastening the motor rotor to the auxiliary impeller section is a hollow shaft.

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