CN113027812A

CN113027812A - Assembling process of radially split two-end support type two-stage cryogenic pump

Info

Publication number: CN113027812A
Application number: CN202110309384.5A
Authority: CN
Inventors: 李俏菊; 刘金龙; 马玉琴; 张高正; 张发杰; 王金法; 程建强; 刘慧娟
Original assignee: XI'AN AEROSPACE PUMPS CO Ltd
Current assignee: XI'AN AEROSPACE PUMPS CO Ltd
Priority date: 2021-03-23
Filing date: 2021-03-23
Publication date: 2021-06-25
Anticipated expiration: 2041-03-23
Also published as: CN113027812B

Abstract

The invention relates to an assembly process of a multistage pump, in particular to an assembly process of a radially split two-end support type two-stage cryogenic pump, which solves the problems that a hydraulic structure of an impeller flow passage and a shell flow passage is difficult to align and a rotor part and a shell are easy to grind in the assembly process of the pump. The invention mainly comprises the following steps: firstly, fixing a pump body; sequentially loading the pump body interstage wear-resistant sleeve, the primary shell opening ring and the secondary shell opening ring; after the rotor is small-mounted, a meter is printed to detect the radial runout of the rotor, and a dynamic balance test is carried out; detaching the secondary impeller part, and mounting a pump shaft and the primary impeller part; supporting two ends of the rotor by using a supporting tool; installing a primary pump cover, a secondary impeller part and a secondary pump cover; measuring the rotor serial quantity, and checking the axial installation size and the radial clearance; installing a thrust bearing part, a free end bearing part and mechanical seals at two ends, and turning after installing the thrust bearing part and the free end bearing part; and turning the vehicle again, and finishing the installation if the vehicle is qualified.

Description

Assembling process of radially split two-end support type two-stage cryogenic pump

Technical Field

The invention relates to an assembly process of a multistage pump, in particular to an assembly process of a radially split two-end support type two-stage cryogenic pump.

Background

The traditional pump structure belongs to a horizontal split and bilateral symmetrical flow passage type, and the relative position of a rotor in a pump body flow passage component can be clearly seen in the assembling process. The structure of the radial split two-end support type two-stage cryogenic pump conforms to the American Petroleum institute standard API610 BB2 type pump structure, the structure of the pump is shown in figure 1, the pump mainly comprises a thrust bearing part 22, a secondary pump cover 14, a secondary impeller part 7, a pump body 1, a pump shaft 10, a primary impeller part 8, a primary pump cover 11, a mechanical seal 23 and a free end bearing part 24, and the relative position between an impeller flow passage and a shell flow passage cannot be visually seen when the whole machine is assembled. Therefore, the phenomenon that the hydraulic structures of the impeller flow channel and the shell flow channel are difficult to align often occurs in the assembling process of the radial subdivision two-stage cryogenic pump with two supporting ends, so that the pump efficiency is reduced, and the turning machine is easy to block and stagnate after the pump body and the pump cover are combined.

Secondly, the pump components are large in size and heavy in weight, and also cause great difficulty in assembly. Moreover, the pump running clearance and the radial clearance are small, and the abrasion between the rotor part and the housing is easily caused.

Disclosure of the invention

The invention aims to solve the problems that the hydraulic structures of an impeller flow passage and a shell flow passage are difficult to align and the grinding between a rotor component and a shell is easy to cause in the assembling process of a radially split two-end supporting type two-stage cryogenic pump, and provides an assembling process of the radially split two-end supporting type two-stage cryogenic pump.

In order to achieve the purpose, the technical scheme provided by the invention is as follows:

the assembling process of the two-stage radial split cryogenic pump with two supporting ends is characterized by comprising the following steps of:

step 1: fixing the pump body to ensure the level of the pump body;

step 2: sequentially installing a pump body interstage wear-resistant sleeve, a primary shell opening ring and a secondary shell opening ring, wherein the pump body interstage wear-resistant sleeve and the secondary shell opening ring are installed at corresponding positions of a secondary vortex chamber, and the primary shell opening ring is installed at corresponding positions of a primary vortex chamber and is fixedly riveted;

and step 3: after the rotor is small, supporting bearings at two ends, marking a meter to detect radial runout of the rotor, performing a dynamic balance test after a radial runout value meets a preset requirement, and enabling balance precision to meet the G1 standard of the rotor balance quality requirement;

the rotor small assembly finger is characterized in that a secondary impeller part and a primary impeller part are arranged on a pump shaft, the secondary impeller part comprises a secondary impeller, a secondary impeller shaft sleeve and a secondary impeller locking nut, and the primary impeller part comprises a primary impeller and a primary impeller locking nut;

and 4, step 4: mounting pump shaft and primary impeller part

4.1) disassembling the secondary impeller part and reserving the primary impeller part; hoisting at a hoisting position of the pump shaft close to the left side of the primary impeller component; the first support and the second support of the two overhanging ends respectively limit the pump shaft to swing along the radial direction so as to ensure the horizontal hoisting of the pump shaft;

4.2) moving the crane to enable the pump shaft to slowly penetrate into the pump body along the horizontal direction, and observing and ensuring that the center of the pump shaft is coincided with the geometric center of the interstage wear-resistant sleeve of the pump body;

4.3) after the front end of the pump shaft slowly penetrates through the pump body interstage wear-resistant sleeve, the radial swing of the support II is not limited any more, and when the pump shaft penetrates through the pump body interstage wear-resistant sleeve to a lifting position and reaches the edge of a right end cover of the pump body, the lifting position is changed from a first lifting position to a second lifting position, so that the pump shaft continuously and slowly penetrates through the pump body interstage wear-resistant sleeve;

4.4) after the pump shaft extends out of the edge of the left end cover of the pump body, horizontally lifting at three positions and one support position of the extending end of the pump shaft; the pump shaft is continuously and slowly moved leftwards until the first-stage impeller port ring and the first-stage shell port ring are installed in place in a matching size manner;

4.5) supporting the pump shaft at the first support and the second support by using a support tool;

the supporting tool comprises a V-shaped block, a lead screw, a nut, a bearing, a sleeve and a bottom plate; the bearing is fixed at the upper end of the sleeve through a bearing sleeve, and the lower end of the sleeve is fixed on the bottom plate; the screw rod penetrates through the nut and the bearing and is coaxially sleeved in the sleeve, and the screw rod is in threaded connection with the nut to form a screw pair to realize transmission;

the top end of the lead screw is provided with a V-shaped block, and a V-shaped groove of the V-shaped block is used for placing a pump shaft;

and 5: mounting pump cover and secondary impeller part

5.1) lifting the first-stage pump cover through a lifting ring, observing and checking that a pump body inlet flow passage and the first-stage pump cover flow passage are smoothly and smoothly extended, then placing a sealing winding pad and a high-low pressure sealing spacer pad on the first-stage pump cover, slowly moving the first-stage pump cover, penetrating through a pump shaft, aligning and matching a spigot, slightly pushing the pump body, screwing in a first-stage pump cover bolt, and screwing a nut; in the process of screwing the nut, detecting the axial gap delta between the pump body and the first-stage pump cover, wherein delta is less than or equal to 0.03 mm;

5.2) mounting of the secondary impeller part

Installing a secondary impeller shaft sleeve on a pump shaft, hoisting a secondary impeller to enable a key groove of the secondary impeller to be upward, finely adjusting a supporting tool at a first supporting position and a second supporting position to enable the center of the pump shaft and the center of a pump body to be basically overlapped, slowly moving the secondary impeller to enable the secondary impeller to penetrate through the pump shaft, measuring the axial size of assembly until the secondary impeller is checked to be installed in place, locking a nut of the secondary impeller and riveting;

5.3) installing a secondary pump cover according to the method of the step 5.1;

step 6: after the secondary pump cover is installed in place, measuring the serial quantity of a pump rotor, checking the axial installation size and the radial clearance, and requiring that the serial quantity of the rotor after the total serial quantity and the hydraulic centering and the serial quantity of a non-driving end meet the preset requirement;

and 7: installing a thrust bearing part, a free end bearing part and two end mechanical seals, and locking;

when a thrust bearing part is installed, the thrust clearance of the bearing is not more than 0.2 mm; turning after installing the thrust bearing part and the free end bearing part; judging whether the rotor rotates uniformly or not, and judging whether rubbing occurs or not;

if the rotor rotates unevenly and/or is scratched, the pump is pumped for maintenance, and the step 1 is executed again after the maintenance is qualified;

if the rotor rotates uniformly and is not scratched, executing the step 8;

and 8: turning the vehicle again, and judging whether the turning force is light and uniform, whether the turning force is scratched or not and whether the turning force is off or not;

if the turning force is not easy and uniform and/or the turning force is scratched and/or abnormal sound exists, the pump is sent for maintenance, and after the maintenance is qualified, the steps are executed again

If the jigger is easy in force, uniform, free of scraping and noise, the installation is completed.

Further, the support tool further comprises a rib plate, one end of the rib plate is fixed on the outer surface of the sleeve, and the other end of the rib plate is fixed on the bottom plate.

Further, the number of the rib plates is 3, and the rib plates are uniformly distributed.

Further, in the step 2, the end faces of the primary shell opening ring and the secondary shell opening ring are tightly leaned against each other, so that the radial jumping of the primary shell opening ring and the secondary shell opening ring is ensured to be in place.

Further, in the step 3, when the secondary impeller part and the primary impeller part are installed, uniformly wiping dry powder molybdenum disulfide on the pump shaft, and smearing a wet anti-seizure agent on the primary impeller mouth ring, the secondary impeller mouth ring and the excircle of the pump body interstage wear-resistant sleeve;

in the step 5.2), when a secondary impeller part is installed, uniformly wiping dry powder molybdenum disulfide on a pump shaft, and smearing a wet anti-seizure agent on the outer circle of a secondary impeller opening ring and the outer circle of a pump body interstage wear-resistant sleeve;

further, the wet anti-seizure agent is oil-immersed molybdenum disulfide.

Further, in step 3, the rotor radial runout value is less than 0.05 mm.

Further, in step 6, the total string quantity of the rotor is 14 +/-0.5 mm, and the string quantity of the rear non-driving end in hydraulic centering is 5 +/-0.5 mm.

The invention has the beneficial effects that:

1. the assembly precision is high, avoids the barring jamming. The invention ensures that the total rotor string quantity and the string quantity of the rear non-driving end in water conservancy centering meet the requirements by controlling the position precision in the assembling process, such as measuring the rotor string quantity and checking the axial installation size and the radial clearance, and avoids the grinding between the rotor part and the shell. When the pump cover is installed, the pump body flow passage is smoothly extended with the primary pump cover and the secondary pump cover, so that the phenomenon that the impeller flow passage and the shell flow passage are difficult to align in a hydraulic structure is avoided. The two-time jiggering in the assembling process ensures that the jiggering jam cannot be caused when the pump runs. When the thrust bearing component is installed, the thrust clearance of the bearing is ensured to be not more than 0.2 mm. The axial clearance delta between the feeler gauge detection pump body and the primary pump cover and between the feeler gauge detection pump body and the secondary pump cover meets the requirement that delta is less than or equal to 0.03 mm. The assembling process ensures the assembling precision of the radially split two-end supporting type two-stage cryogenic pump, improves the product quality and the product running stability, and prolongs the service life of the product.

2. And strictly monitoring the data of the installation positioning spigot in the assembling process, and adjusting the assembling clearance. In the rotor trial assembly process, the first-stage pump cover and the second-stage pump cover are installed to be aligned with the matched seam allowance and are measured and verified by the feeler gauge, so that the plugging gap is zero, the deviation of the crosstalk amount is reduced, and the phenomenon that the hydraulic structures of the impeller flow passage and the shell flow passage are not aligned to influence the pump efficiency is avoided.

Drawings

FIG. 1 is a schematic view of a radially split two-stage cryogenic pump with two end supports;

FIG. 2 is a schematic structural diagram of an embodiment of the invention with an interstage wear sleeve, a primary housing port ring and a secondary housing port ring installed;

FIG. 3 is a schematic structural diagram of a rotor small package in an embodiment of the invention;

FIG. 4 is a schematic structural view of a pump shaft and a primary impeller member mounted in a pump body according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of the structure of the pump cover and the secondary impeller member of the embodiment of the present invention;

FIG. 6 is a schematic structural diagram of a support tool in an embodiment of the present invention;

the reference numbers are as follows:

1-pump body, 2-pump body interstage wear-resistant sleeve, 3-primary housing port ring, 4-secondary housing port ring, 5-primary vortex chamber, 6-secondary vortex chamber, 7-secondary impeller part, 8-primary impeller part, 9-rotor, 10-pump shaft, 11-primary pump cover, 12-sealing winding pad, 13-high and low pressure sealing spacer pad, 14-secondary pump cover, 15-V-shaped block, 16-lead screw, 17-nut, 18-bearing, 19-sleeve, 20-bottom plate, 21-ribbed plate, 22-thrust bearing part, 23-mechanical seal and 24-free end bearing part;

q1-hoisting one position, Q2-hoisting two positions, Q3-hoisting three positions, Z1-supporting one position and Z2-supporting two positions.

Detailed Description

The technical scheme of the invention is clearly and completely described in the following with reference to the accompanying drawings.

An assembly process of a radially split two-end support type two-stage cryogenic pump comprises the following steps:

step 1: the pump body 1 is fixed on a base for the pump, and the pump body is ensured to be horizontally positioned.

Step 2: as shown in figure 2, a pump body interstage wear-resistant sleeve 2, a primary shell mouth ring 3 and a secondary shell mouth ring 4 are sequentially arranged, and then 3 seam-riding screws are uniformly distributed on the periphery and screwed and riveted. The pump body interstage wear-resistant sleeve 2 and the secondary shell port ring 3 are arranged at corresponding positions of the secondary volute chamber 6, and the primary shell port ring 3 is arranged at corresponding positions of the primary volute chamber 5. Details should be noted at the time of loading: the end faces of the primary shell opening ring 3 and the secondary shell opening ring 4 must be tightly leaned to ensure that the primary shell opening ring 3 and the secondary shell opening ring 4 radially jump in place.

And step 3: as shown in fig. 3, after the rotor 9 is small, the rotor 9 is mounted on a dynamic balancing machine, bearings at two ends are supported, the radial runout of the rotor 9 is detected by a dial, the radial runout value of the rotor 9 is less than 0.05mm, and then the rotor 9 is subjected to a dynamic balance test and is executed according to the G1 standard of the balance quality requirement of the rotor 9.

The rotor 9 is small, namely the secondary impeller part 7 and the primary impeller part 8 are arranged on the pump shaft 10. The secondary impeller part 7 comprises a secondary impeller, a secondary impeller shaft sleeve and a secondary impeller locking nut, and the primary impeller part 8 comprises a primary impeller and a primary impeller locking nut. When the secondary impeller and the primary impeller are installed, dry powder molybdenum disulfide is uniformly wiped on a pump shaft, the dosage is not too much, and the coating dosage is preferably that the powder cannot fall off. And (3) coating a wet anti-seizure agent on the matching part of the relative motion, such as a primary impeller mouth ring, a secondary impeller mouth ring and the excircle of the pump body interstage wear-resistant sleeve, wherein the wet anti-seizure agent is preferably oil-immersed molybdenum disulfide.

And 4, step 4: mounting pump shaft 10 and primary impeller part 8

As shown in fig. 4, the secondary impeller member 7 is removed and the primary impeller member 8 is retained. The pump shaft 10 is lifted at a lifting position Q1 on the left side close to the primary impeller. At the positions of the first support Z1 and the second support Z2 of the two overhanging ends, the pump shaft 10 is manually limited to swing along the radial direction respectively, so that the horizontal hoisting is ensured.

The crane is moved to enable the pump shaft 10 to slowly penetrate into the pump body 1 along the horizontal direction, and meanwhile, the geometric center of the pump shaft 10 is observed and guaranteed to be coincided with the geometric center of the pump body interstage wear-resistant sleeve 2.

After the pump shaft 10 slowly penetrates through the pump body interstage wear-resistant sleeve 2, the radial swing of the second support Z2 is not limited any more, the first lifting position Q1 reaches the edge of the right end cover of the pump body 1, and after the pump shaft 10 penetrates through the pump body interstage wear-resistant sleeve 2 to the first lifting position Q1 and reaches the edge of the right end cover of the pump body 1, the lifting position is changed from the first lifting position Q1 to the second lifting position Q2, so that the pump shaft 10 continuously and slowly penetrates through the pump body interstage wear-resistant sleeve 2;

after the pump shaft 10 extends out of the edge of the left end cover of the pump body 1, the extending end of the pump shaft 10 is changed into a three-position Q3 for lifting and a Z1 for horizontally lifting, the pump shaft 10 is continuously and slowly moved leftwards, and the pump shaft 10 is ensured to be always in a horizontal position until the primary impeller port ring and the primary casing port ring 3 are installed in place in a matching size mode. The pump body interstage wear-resistant sleeve 2, the primary shell mouth ring 3, the secondary shell mouth ring 4 and the like are prevented from being collided and scratched in the moving process.

The pump shaft 10 is supported at support one Z1 and support two Z2 using support tooling. As shown in fig. 6, the support tool includes a V-shaped block 15, a lead screw 16, a nut 17, a bearing 18, a sleeve 19, a bottom plate 20, and a rib 21. The bearing 18 is fixed at the upper end of the sleeve 19 through a bearing sleeve, the lower end of the sleeve 19 is fixed on the bottom plate 20, the lead screw 16 penetrates through the nut 17 and the bearing 18 and is coaxially sleeved in the sleeve 19, the lead screw 16 is in threaded connection with the nut 17 to form a screw pair to realize transmission, the top end of the lead screw 16 is provided with the V-shaped block 15, the V-shaped groove of the V-shaped block 15 is used for placing the pump shaft 10, and the height of the pump shaft 10 on the horizontal plane is adjusted through the screw pair formed by the lead screw 16 and the nut 17. In order to keep the stability of the whole supporting tool, 3 rib plates 21 which are uniformly distributed are further arranged, one end of each rib plate 21 is fixed on the outer surface of the corresponding sleeve 19, the other end of each rib plate 21 is fixed on the corresponding bottom plate 20, the supporting tool works stably in the adjusting process, the transmission precision is high, self-locking is achieved through the lead screw 16 and the screw 17, and the supporting tool has good speed reducing performance.

And 5: mounting pump cover and secondary impeller part 7

First, the primary pump cover 11 is installed, then the secondary impeller part 7 is installed, and finally the secondary pump cover 14 is installed, and the structural schematic diagram after installation is shown in fig. 5.

Installing a first-stage pump cover 11: the rings lift the first-stage pump cover 11 through two ring screw holes in the outer edge of the first-stage pump cover 11, an inlet flow channel of the pump body 1 and a flow channel of the first-stage pump cover 11 are observed and checked to be smoothly extended, after no problem is checked, a sealing winding pad 12 and a high-low pressure sealing spacer pad 13 are placed on the first-stage pump cover 11, the first-stage pump cover 11 is slowly moved, passes through the pump shaft 10, is aligned with a matching seam allowance, is slightly pushed into the pump body 1, is screwed into a first-stage pump cover 11 bolt, and is symmetrically screwed with nuts. In the process of screwing the nuts, the widths of the phase positions of the pump body 1 and the primary pump cover 11 are always kept consistent, the axial gap delta between the pump body 1 and the primary pump cover 11 is detected by using a feeler gauge, the delta is less than or equal to 0.03mm, and all bolts are uniformly screwed according to the designed pretightening force.

Mounting the secondary impeller part: first, a secondary impeller sleeve is mounted on the pump shaft 10 and pushed until the shoulder abuts. The pump shaft is rotated to enable the impeller to be matched with the key groove upwards, the matching key is placed on the shaft, the secondary impeller is lifted, the key groove position of the secondary impeller is enabled to be upwards, the secondary impeller slowly moves to penetrate through the pump shaft 10 and is pushed into the secondary impeller, when the matching position of the secondary impeller is pushed into, the height and the left and right of the pump shaft 10 are finely adjusted through the supporting tool, the center of the pump shaft 10 and the center of the pump body 1 basically keep coincident, and therefore the secondary impeller can be. During the process of installing the secondary impeller, the pushing of the pump shaft 10 to the far left end of the pump body 1 is a guarantee that the secondary impeller sleeve is installed in place, as shown in the position of the pump shaft 10 in fig. 5. And finally, measuring the axial dimension of the assembly, checking that the secondary impeller is installed in place, locking a nut of the secondary impeller, and using a set screw to perform jacking and riveting.

When the secondary impeller member 7 is installed, dry powder molybdenum disulfide is wiped evenly on the pump shaft 10. And (3) coating a wet anti-seizure agent on the matching part of the relative motion, such as the secondary impeller opening ring and the excircle of the pump body interstage wear-resistant sleeve 2, wherein the wet anti-seizure agent is preferably oil-immersed molybdenum disulfide.

Installing a secondary pump cover 14: the method of attaching the secondary pump cover 14 is identical to the method of attaching the primary pump cover 11.

Step 6: the rotor 9 is subjected to string quantity detection under the condition that two ends of the rotor are not supported by rolling bearings, and the rotor is properly pulled to avoid friction and pulling damage at the position of dynamic and static matching. The string pulling quantity is based on measured accurate data, repeated operation cannot be carried out, and friction and scratching are prevented. As shown in fig. 5, after the secondary pump cover 14 is installed in place, the amount of the pump rotor 9 string is measured, the axial installation size and the radial clearance are checked, the total amount of the rotor 9 string is controlled to be 14 ± 0.5mm, and the amount of the rotor string at the rear non-driving end after hydraulic centering is 5 ± 0.5 mm.

And 7: fig. 1 shows a schematic structure of the assembled thrust bearing member 22, free end bearing member 24, and both ends mechanical seal 23.

Mounting the thrust bearing member 22: before installing the thrust bearing body, the mechanical seal 23 is slightly pushed in, and the shaft shoulder is rounded during pushing so as to prevent scratching. When the mechanical seal 23 is pushed in, the positioning spigot of the gland cover is not pushed in temporarily, and the gland nut is screwed on the belt. According to the pump string quantity and the half string size, the axial positioning size of the thrust bearing is adjusted through the adjusting sleeve and the adjusting gland, the mounted pump half string is ensured to meet the process requirements, the thrust bearing part is installed, and the thrust gap of the bearing is ensured to be not more than 0.2 mm. The thrust bearing body is positioned by a stop opening, and radial adjustment is mainly matched and positioned by the stop opening.

Mounting the free end bearing member 24: the assembly of the free end bearing member 24 is the same as the thrust end bearing member 22. The inner ring of the free end bearing is axially positioned, and the outer ring of the free end bearing is in a free state.

After the thrust bearing part 22 and the free end bearing part 24 are installed, turning is carried out, namely the pump shaft 10 is slightly rotated along the rotation direction of the pump, and whether the rotor 9 rotates uniformly or not is judged, so that the phenomenon of scraping or not is caused. If the rotor rotates unevenly and/or is scratched, the pump is sent to overhaul, and the step 1 is executed again after the overhaul is qualified; and if the rotor 9 rotates uniformly and is not scratched, executing the step 8.

Installing two-end mechanical seal 23: and screwing down the gland bolt to lock the mechanical seal locking device.

And 8: turning a vehicle again, the turning of the vehicle is ensured to be easy, uniform and have no scratch or noise. If the turning force is not easy and uniform and/or rubbing is performed and/or abnormal sound is generated, the pump is sent to overhaul, and the step 1 is executed again after the overhaul is qualified; if the jigger is easy in force, uniform, free of scraping and noise, the installation is completed.

The effect after the installation: through continuous performance tests and mechanical operation tests for 4 hours, the cryopump installed by the new process runs stably, no bearing generates heat, no abnormal sound, no endless loop grinding or locking and other phenomena exist in the operation period, and the efficiency of the cryopump is superior to the design parameter requirements.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements, etc. made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. The assembling process of the two-stage radial split cryogenic pump with two supported ends is characterized by comprising the following steps of:

step 1: fixing the pump body (1) to ensure that the pump body (1) is horizontal;

step 2: sequentially installing a pump body interstage wear-resistant sleeve (2), a primary shell opening ring (3) and a secondary shell opening ring (4), wherein the pump body interstage wear-resistant sleeve (2) and the secondary shell opening ring (4) are installed at corresponding positions of a secondary vortex chamber (6), and the primary shell opening ring (3) is installed at corresponding positions of a primary vortex chamber (5) and is fixedly riveted;

and step 3: after the rotor (9) is small, bearings at two ends are supported, the radial runout of the rotor (9) is detected by a meter, a dynamic balance test is carried out after the radial runout value meets the preset requirement, and the balance precision meets the G1 standard of the balance quality requirement of the rotor (9);

the rotor (9) is provided with a secondary impeller part (7) and a primary impeller part (8) on a pump shaft (10) in a small finger mode, the secondary impeller part (7) comprises a secondary impeller, a secondary impeller shaft sleeve and a secondary impeller locking nut, and the primary impeller part (8) comprises a primary impeller and a primary impeller locking nut;

and 4, step 4: mounting pump shaft (10) and the first impeller part (8)

4.1) detaching the secondary impeller part (7) and reserving the primary impeller part (8); hoisting at a hoisting position (Q1) of the pump shaft (10) close to the left side of the primary impeller component (8); the positions of a first support (Z1) and a second support (Z2) of the two overhanging ends respectively limit the pump shaft (10) to swing along the radial direction so as to ensure that the pump shaft (10) is horizontally lifted;

4.2) moving the crane to enable the pump shaft (10) to slowly penetrate into the pump body (1) along the horizontal direction, and observing and ensuring that the center of the pump shaft (10) is superposed with the geometric center of the pump body interstage wear-resistant sleeve (2);

4.3) after the front end of the pump shaft (10) slowly penetrates through the pump body interstage wear-resistant sleeve (2), the radial swing of the support II (Z2) is not limited any more, and when the pump shaft (10) penetrates through the pump body interstage wear-resistant sleeve (2) to a first lifting position (Q1) and reaches the edge of a right end cover of the pump body (1), the lifting position is changed from a first lifting position (Q1) to a second lifting position (Q2), so that the pump shaft (10) continuously and slowly penetrates through the pump body interstage wear-resistant sleeve (2);

4.4) after the pump shaft (10) extends out of the edge of the left end cover of the pump body (1), horizontally hoisting at a hoisting three position (Q3) and a supporting one (Z1) at the extending end of the pump shaft (10); the pump shaft (10) is continuously and slowly moved leftwards until the primary impeller opening ring and the primary shell opening ring (3) are installed in place in a matching size manner;

4.5) supporting the pump shaft (10) at a first support (Z1) and a second support (Z2) by using a supporting tool;

the supporting tool comprises a V-shaped block (15), a lead screw (16), a nut (17), a bearing (18), a sleeve (19) and a bottom plate (20); the bearing (18) is fixed at the upper end of the sleeve (19) through a bearing sleeve, and the lower end of the sleeve (19) is fixed on the bottom plate (20); the screw rod (16) penetrates through the nut (17) and the bearing (18) and is coaxially sleeved in the sleeve (19), and the screw rod (16) is in threaded connection with the nut (17) to form a screw pair to realize transmission;

a V-shaped block (15) is mounted at the top end of the lead screw (16), and a V-shaped groove of the V-shaped block (15) is used for placing the pump shaft (10);

and 5: mounting pump cover and secondary impeller parts (7)

5.1) lifting the first-stage pump cover (11) through a lifting ring, observing and checking that an inlet flow channel of the pump body (1) and a flow channel of the first-stage pump cover (11) are smoothly and smoothly extended, then placing a sealing winding pad (12) and a high-low pressure sealing spacing pad (13) on the first-stage pump cover (11), slowly moving the first-stage pump cover (11), penetrating through a pump shaft (10), aligning and matching a spigot, slightly pushing the pump body (1), screwing in a bolt of the first-stage pump cover (11), and screwing down a nut; in the process of screwing the nut, detecting the axial gap delta between the pump body (1) and the primary pump cover (11) and ensuring that delta is less than or equal to 0.03 mm;

5.2) mounting of the Secondary impeller part (7)

Mounting a secondary impeller shaft sleeve on a pump shaft (10), hoisting a secondary impeller to enable the position of a key groove of the secondary impeller to be upward, finely adjusting a supporting tool at a first supporting part (Z1) and a second supporting part (Z2) to enable the center of the pump shaft (10) and the center of a pump body (1) to be basically overlapped, slowly moving the secondary impeller to enable the secondary impeller to penetrate through the pump shaft (10), measuring the axial dimension of assembly until the secondary impeller is checked to be mounted in place, and locking and riveting a nut of the secondary impeller;

5.3) installing a secondary pump cover (14) by adopting the same method as the step 5.1);

step 6: after the secondary pump cover (14) is installed in place, measuring the serial quantity of the pump rotor (9), checking the axial installation size and the radial gap, and requiring that the total serial quantity of the rotor (9) and the serial quantity of the rear non-driving end after hydraulic centering meet the preset requirement;

and 7: installing a thrust bearing part (22), a free end bearing part (24) and two end mechanical seals (23) and locking;

when the thrust bearing part (22) is installed, the thrust clearance of the bearing is not more than 0.2 mm; turning after installing a thrust bearing part (22) and a free end bearing part (23); judging whether the rotor (9) rotates uniformly or not, and judging whether scratch occurs or not;

if the rotor (9) rotates unevenly and/or is scratched, the pump is pumped for maintenance, and the step 1 is executed again after the maintenance is qualified;

if the rotor (9) rotates uniformly and is not scratched, executing the step 8;

if the turning force is not easy and uniform and/or rubbing is performed and/or abnormal sound is generated, the pump is sent to overhaul, and the step 1 is executed again after the overhaul is qualified;

2. The assembly process of a radially split two-end supported two-stage cryogenic pump according to claim 1, wherein: in the step 4.5), the supporting tool further comprises a rib plate (21), one end of the rib plate (21) is fixed on the outer surface of the sleeve (19), and the other end of the rib plate (21) is fixed on the bottom plate (20).

3. The assembly process of a radially split two-end supported two-stage cryogenic pump according to claim 2, wherein: the number of the ribbed plates (21) is 3, and the ribbed plates are uniformly distributed.

4. The assembly process of a radially split two-end supported two-stage cryogenic pump according to any of claims 1 to 3, wherein: in the step 2, the end faces of the primary shell opening ring (3) and the secondary shell opening ring (4) are tightly leaned to ensure that the primary shell opening ring (3) and the secondary shell opening ring (4) radially jump in place.

5. The assembly process of a radially split two-end supported two-stage cryogenic pump according to claim 4, wherein: in the step 3, when the secondary impeller part (7) and the primary impeller part (8) are installed, uniformly wiping dry powder molybdenum disulfide on the pump shaft (10), and smearing a wet anti-seizure agent on the primary impeller mouth ring, the secondary impeller mouth ring and the excircle of the pump body interstage wear-resistant sleeve (2);

in the step 5.2), when the secondary impeller part (7) is installed, dry powder molybdenum disulfide is uniformly wiped on the pump shaft (10), and a wet anti-seizure agent is smeared at the outer circle of the secondary impeller mouth ring and the pump body interstage wear-resistant sleeve (2).

6. The assembly process of a radially split two-end supported two-stage cryogenic pump according to claim 5, wherein: the wet anti-seizure agent is oil-immersed molybdenum disulfide.

7. The assembly process of a radially split two-end supported two-stage cryogenic pump according to claim 6, wherein: in step 3, the radial runout value of the rotor (9) is less than 0.05 mm.

8. The assembly process of a radially split two-end supported two-stage cryogenic pump according to claim 7, wherein: in step 6, the total string quantity of the rotor (9) is 14 +/-0.5 mm, and the string quantity of the rear non-driving end in hydraulic centering is 5 +/-0.5 mm.