CN112815096A

CN112815096A - Sodium pump maintenance seal and use method thereof

Info

Publication number: CN112815096A
Application number: CN202110147504.6A
Authority: CN
Inventors: 崔正军; 侯振威; 郭建; 霍素梅
Original assignee: Shenyang Beitan Sealing Co ltd
Current assignee: Shenyang Beitan Sealing Co ltd
Priority date: 2021-02-03
Filing date: 2021-02-03
Publication date: 2021-05-18

Abstract

A sodium pump overhauls and seals and its operation method, including base part, housing part and gland; the sealing gland is fixed on a shaft platform of the pump main shaft through bolts and rotates along with the pump main shaft as a moving ring, the base part is installed on a sodium pump body as a static ring, the shell part is installed on the upper part of the base part, the base part and the shell part form a sealing cavity together with the pump main shaft, the sealing gland is installed in the shell of the shell part and forms a sealing friction pair together with a sealing ring installed on a sealing supporting seat of the base part, and therefore media and gas leaked out from the pump cavity are blocked. The seal is a conical surface narrow seal, and the conical surface of the seal gland is in contact with the edge of the polytetrafluoroethylene ring on the stationary ring for sealing. The sealing has the advantages of narrow contact surface, larger pressure-resistant section and difficult deformation. The friction heat and the abrasion can be reduced, the service life is prolonged, and meanwhile, the leakage rate can be reduced.

Description

Sodium pump maintenance seal and use method thereof

Technical Field

The invention belongs to the technical field of sealing, and particularly relates to a sodium pump maintenance seal for maintaining the sealing property of a pump air cavity and the outside and supporting a rotor when a mechanical seal of a sodium pump is replaced or maintained, and a use method of the sodium pump maintenance seal.

Background

Along with technological progress, electric power is more and more wide as an important power source, the usage amount is more and more large, common thermal power plants use coal as fuel, the combustion of coal can discharge a large amount of pollutants into the atmosphere, the environment is polluted, the produced carbon dioxide can aggravate the global greenhouse effect, along with the mass exploitation in recent years, the amount of coal as a non-renewable resource is continuously reduced, the coal must be replaced by other energy sources in the long-term development, nuclear power as a novel clean energy source is more and more popular and popularized, and nuclear power plants are power plants which utilize energy released by nuclear fission or nuclear fusion reaction to generate electric energy. Uranium and fission products have strong radioactivity, once leakage can cause great harm to the health of workers of the nuclear power station and residents around the nuclear power station, pollution and damage are caused to the surrounding environment, so that reliable protective measures are necessary, and the requirement on the leakage rate is far higher than that of common pump sealing. Sodium is used as a fast reactor heat exchanger to ensure the stability of the inside of the reactor. The safety of the sodium pump is very important as a key device in nuclear power. Because sodium chemical property is very active, it can react violently with water and air and the final sodium hydroxide has strong corrosivity, in order to ensure safety, when the pump set overhauls mechanical seal part and bearing part, it is necessary to have a part with strong sealing property to play the role of sealing and supporting the rotor when the pump set overhauls mechanical seal part and bearing part.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a sodium pump overhauling seal and a using method thereof. When the sodium pump is stopped and the shaft seal and the bearing component are replaced, the maintenance sealing component supports the weight of the whole rotor and keeps the balance of the rotor, the pipeline at the lower part of the maintenance sealing component is filled with gas, and the upward force generated by the bellows pneumatic component pushes the sealing ring to be in contact with the sealing gland on the rotor, so that the effect of isolating the inner cavity of the sodium pump from the external environment is achieved.

In order to achieve the purpose, the invention adopts the following technical scheme:

a sodium pump maintenance seal comprises a base part, a shell part and a seal gland; the sealing gland is fixed on a shaft platform of the pump main shaft through bolts and rotates along with the pump main shaft as a moving ring, the base part is installed on a sodium pump body as a static ring, the shell part is installed on the upper part of the base part, the base part and the shell part form a sealing cavity together with the pump main shaft, the sealing gland is installed in the shell of the shell part and forms a sealing friction pair together with a sealing ring installed on a sealing supporting seat of the base part, and therefore media and gas leaked out from the pump cavity are blocked.

The base part comprises a base, a corrugated pipe pneumatic assembly, a main shaft corrugated pipe, a spiral spring assembly, a sealing support seat, a sealing ring and a sealing compression ring; the base is fixed on the pump body by bolts, the pneumatic assembly of the corrugated pipe is welded into a whole by a pneumatic spring corrugated pipe, an upper plug and a lower plug, the lower plug of a group of pneumatic assemblies of the corrugated pipe is welded on the base, the lower plug of the pneumatic assembly of the corrugated pipe is provided with an air inlet and is communicated with the air inlet arranged on the base, the inlet end of the air inlet of the base is connected with an external air source, the upper plug is connected with a sealing support seat by bolts, gas enters the pneumatic assembly of the corrugated pipe from the air inlet during maintenance and sealing work, the sealing support seat is lifted at the top of the pneumatic assembly of the corrugated pipe, and a sealing ring arranged on the sealing support seat; the spiral spring assembly comprises a support sleeve, a spring seat and a spring, wherein a group of support sleeves are fixedly arranged on the base, the spring seat and the spring are arranged in the support sleeve, the spring is sleeved on the spring seat, the spring seat penetrates through a hole at the top of the seal support seat and is fixed on the seal support seat by a nut, the spring arranged in the support sleeve is supported by the spring seat when the seal support seat is lifted, the spring is compressed to generate downward thrust, when the maintenance is finished, the pneumatic assembly of the corrugated pipe is not inflated any more, the compressed spring pushes the seal support seat downwards, on one hand, the sealing surface can not be separated due to gluing, on the other hand, the pneumatic spring corrugated pipe and the main shaft corrugated pipe on the pneumatic assembly of the corrugated pipe which generates tensile deformation after being stretched are enabled to recover to the initial state, the main shaft corrugated pipe, connect base and sealed supporting seat as a whole, can guarantee that whole quiet ring does not have the leak source, when the maintenance finishes, when no longer aerifing in the bellows pneumatic component, the main shaft bellows pulls back the normal position with sealed supporting seat together with the spring under self elastic action, in the recess on the sealed supporting seat was installed to the sealing ring, bolt spiro union was used on sealed supporting seat and compressed tightly the sealing ring to the sealed clamping ring.

The housing part comprises a housing mounted on the upper part of the base part and a support part mounted on the upper part of the housing, and when the pump is stopped and the shaft seal and the bearing part are replaced, the support part is inserted into the main shaft boss of the pump to support the weight of the whole rotor and keep the balance of the rotor.

The supporting part comprises a flange, a nut, a screw, a supporting part corrugated pipe and a supporting block; the supporting block is arranged at the front end of the screw, when the pump is stopped and the shaft seal and the bearing part are replaced, the supporting block is inserted into a main shaft boss of the pump to support the weight of the whole rotor and keep the balance of the rotor, the nut is sleeved at the tail part of the screw, the flange is arranged on the shell by a bolt and sleeves the nut in the shell, the nut is rotated before replacing the bearing, the nut is wrapped by the flange and the shell and cannot axially move except for rotation, the screw is pushed by the internal thread of the nut to axially move back and forth, and the front end supporting block is driven to advance and retreat; the outer diameter of the screw is welded with a supporting component corrugated pipe, and the supporting component corrugated pipe blocks the overflow of the medium and gas in the cavity.

The contact surface of the sealing gland and the sealing ring is a conical surface, and the section of the sealing ring is rectangular.

A use method of a sodium pump overhaul seal comprises the following steps:

when the pump normally works, the maintenance seal is in a non-working state, the supporting block in the supporting part is retracted into the shell, the pneumatic component of the corrugated pipe is not inflated, the sealing supporting seat is sunk, the sealing ring is separated from the sealing gland, and the main shaft corrugated pipe, the spring and the pneumatic spring corrugated pipe are all in an initial state; when the pump is stopped and the shaft seal and the bearing part are replaced, the nut in the supporting part is rotated, the screw pushes the supporting block to move under the action of the thrust of the internal thread of the nut, the supporting block is clamped on a spindle shaft table to support a pump spindle, the pipeline at the lower part of the maintenance seal is filled with gas, the bellows pneumatic assembly generates upward force under the action of internal high-pressure gas to overcome the resistance generated by the compression of the spring in the spiral spring assembly to push the sealing ring to be attached to the lower conical surface of the sealing gland on the pump spindle, the effect of isolating the cavity in the pump from the external environment is achieved, the medium in the pump is prevented from leaking to the outside, the weight of the whole rotor; after the maintenance is finished, the pneumatic assembly of bellows is inside no longer aerifing, and sealed supporting seat falls back under the action of gravity, and the sealing ring is thrown off with gland, and the spring kick-backs, and the pulling sealed supporting seat falls back, has prevented that main shaft bellows and pneumatic spring bellows from being unable to resume former height because of the atress warp, and then causes the unable normal throw-off of sound ring.

The invention has the beneficial effects that:

(1) the seal is a conical surface narrow seal, and the conical surface of the seal gland is in contact with the edge of the polytetrafluoroethylene ring on the stationary ring for sealing. The sealing has the advantages of narrow contact surface, larger pressure-resistant section and difficult deformation. The friction heat and the abrasion can be reduced, the service life is prolonged, and meanwhile, the leakage rate can be reduced.

(2) Adopt bellows pneumatic component as elevating system, the lifting force of pushing is bigger, and the accessible inflation volume controls the thrust size, operates more reliable and more stable.

(3) The edges and corners of the conical surface are contacted, so that the condition that the friction pair is not closed tightly due to the fact that impurities are accumulated on the sealing surface can be prevented.

(4) The pneumatic spring bellows and the spiral spring respectively control the rising and falling of the sealing ring, the sealing ring is lifted under the action of the pneumatic spring during maintenance, and the sealing ring falls under the action of the elastic force of the spring after the maintenance is finished, so that the situation that the pneumatic spring of the bellows and the main shaft bellows cannot restore the original position due to extension caused by stretching is prevented, and the situation that the gluing of a friction pair cannot be disengaged is prevented, so that the sealing failure is caused.

(5) The seal adopts a structure combining a welded corrugated pipe and a conical surface narrow seal, has better sealing performance compared with the common mechanical seal, can achieve safety without leakage, and has the leakage rate lower than 1 multiplied by 10^-6pa·m³And/s, the requirement of the nuclear pump on safety can be ensured.

(6) The sealing not only plays a role of stopping sealing, but also plays a role of supporting the rotor when the bearing is replaced, so that the sealing device is dual-purpose, the cost is saved, meanwhile, a tool for maintaining the bearing is not required to be stored independently, the maintenance procedure is simplified, and the maintenance auxiliary working time is saved.

Drawings

FIG. 1 is a schematic view of a sodium pump service seal structure of the present invention;

1-base part, 11-base, 121-pneumatic spring bellows, 122-upper plug, 123-lower plug, 13-spindle bellows, 141-support sleeve, 142-spring seat, 143-spring, 15-seal support seat, 16-seal ring, 17-seal press ring, 2-housing part, 21-housing, 22-support part, 221-support block, 222-screw, 223-nut, 224-flange, 225-support part bellows, 3-seal gland, 4-pump spindle.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples.

As shown in fig. 1, the sodium pump overhaul seal comprises a base part 1, a shell part 2 and a seal gland 3; the sealing gland 3 is fixed on a boss of the pump main shaft 4 through bolts and rotates together with the pump main shaft 4 as a movable ring, the base part 1 is installed on a sodium pump body as a static ring, the shell part 2 is installed on the upper part of the base part 1, the base part 1 and the shell part 2 form a sealing cavity together with the pump main shaft 4, the sealing gland 3 is installed in a shell 21 of the shell part 2 and forms a sealing friction pair together with a sealing ring 16 installed on a sealing support seat 15 of the base part 1 so as to block media and gas leaked out of a pump cavity.

The base part 1 comprises a base 11, a corrugated pipe pneumatic assembly, a main shaft corrugated pipe 13, a spiral spring assembly, a sealing support seat 15, a sealing ring 16 and a sealing press ring 17; the base 11 is fixed on the pump body by bolts, the bellows pneumatic assembly is welded into a whole by a pneumatic spring bellows 121, an upper plug 122 and a lower plug 123, the lower plug 123 of a group of bellows pneumatic assemblies is welded on the base 11, the lower plug 123 of the bellows pneumatic assembly is provided with an air inlet and communicated with the air inlet arranged on the base 11, the inlet end of the air inlet of the base 11 is connected with an external air source, the upper plug 122 is connected with a sealing support seat 15 by bolts, air enters the bellows pneumatic assembly from the air inlet during maintenance and sealing work, the sealing support seat 15 is lifted at the top of the bellows pneumatic assembly, a sealing ring 16 arranged on the sealing support seat 15 is lifted to be tightly attached to a sealing gland 3, and sealing of media in the; the spiral spring assembly comprises a support sleeve 141, a spring seat 142 and a spring 143, a group of support sleeves 141 are fixedly arranged on the base 11, the spring seat 142 and the spring 143 are arranged in the support sleeve 141, the spring 143 is sleeved on the spring seat 142, the spring seat 142 penetrates through a hole at the top of the seal support seat 15 and is fixed on the seal support seat 15 through a nut, the spring 143 arranged in the support sleeve 141 is supported by the spring seat 142 when the seal support seat 15 is lifted, the spring 143 is compressed to generate downward thrust, when the maintenance is finished and the bellows pneumatic assembly is not inflated any more, the compressed spring 143 pushes the seal support seat 15 downwards, on one hand, the sealing surface is prevented from being incapable of being separated due to gluing, on the other hand, the pneumatic spring bellows 121 and the main shaft bellows 13 on the bellows pneumatic assembly which are stretched and deformed are enabled to recover to the initial state, the main shaft bellows 13 is, and upper and lower both ends weld respectively on base 11 and seal support seat 15, connect base 11 and seal support seat 15 as a whole, can guarantee that whole quiet ring does not have the leak source, and when the maintenance was finished, when not aerifing in the pneumatic subassembly of bellows, main shaft bellows 13 pulls back the normal position with spring 143 together with seal support seat 15 under self elastic action, sealing ring 16 installs in the recess on seal support seat 15, and seal clamping ring 17 is with bolt spiro union on seal support seat 15 and compress tightly sealing ring 16.

The shell component 2 comprises a shell 21 and a supporting component 22, wherein the shell 21 is arranged on the upper part of the base component 1, the supporting component 22 is arranged on the upper part of the shell 21, and when the pump is stopped and the shaft seal and the bearing component are replaced, the supporting component 22 is inserted into the shaft platform of the pump main shaft 4 to support the weight of the whole rotor and keep the balance of the rotor.

The support member 22 comprises a flange 224, a nut 223, a screw 222, a support member bellows 225 and a support block 221; the supporting block 221 is installed at the front end of the screw 222, when the pump is stopped and the shaft seal and the bearing part are replaced, the supporting block 221 is inserted into a shaft boss of the pump spindle 4 to support the weight of the whole rotor and keep the balance of the rotor, the nut 223 is sleeved at the tail of the screw 222, the flange 224 is installed on the shell 21 through bolts and sleeves the nut 223 in the shell, the nut 223 is rotated before the bearing is replaced, the nut 223 is wrapped by the flange 224 and the shell 21 and cannot axially move except for rotation, the screw 222 is pushed to move back and forth along the axial direction through internal threads of the nut 223, and the front end supporting block 221 is driven to move forward; the outer diameter of the screw 222 is welded with a supporting component corrugated pipe 225, and the supporting component corrugated pipe 225 blocks the medium and gas in the cavity from overflowing.

The contact surface of the sealing gland 3 and the sealing ring 16 is a conical surface, and the section of the sealing ring 16 is rectangular.

A use method of a sodium pump overhaul seal comprises the following steps:

when the pump works normally, the maintenance seal is in a non-working state, the supporting block 221 in the supporting part 22 is retracted into the shell 21, the pneumatic assembly of the corrugated pipe is not inflated, the seal supporting seat 15 sinks, the seal ring 16 is separated from the seal gland 3, and the main shaft corrugated pipe 13, the spring 143 and the pneumatic spring corrugated pipe 121 are all in an initial state; when the pump is stopped and the shaft seal and the bearing part are replaced, the nut 223 in the support part 22 is rotated, the screw 222 pushes the support block 221 to move under the action of the thrust of the internal thread of the nut 223, the support block 221 is clamped on the spindle boss to support the pump spindle 4, the pipeline at the lower part of the maintenance seal is filled with gas, the bellows pneumatic component generates upward force under the action of internal high-pressure gas to overcome the resistance generated by the compression of the spring 143 in the spiral spring component to push the seal ring 16 to be attached to the lower conical surface of the seal gland 3 on the pump spindle 4, the effect of isolating the inner cavity of the pump from the external environment is achieved, the medium in the pump is prevented from leaking to the outside, the weight of the whole; after the overhaul is finished, the interior of the bellows pneumatic assembly is not inflated any more, the sealing support seat 15 falls back under the action of gravity, the sealing ring 16 is separated from the sealing gland 3, the spring 143 rebounds, the sealing support seat 15 is pulled to fall back, the main shaft bellows 13 and the pneumatic spring bellows 121 are prevented from being deformed due to stress and then being unable to recover the original height, and further the movable and static rings are unable to be normally separated.

Claims

1. A sodium pump maintenance seal is characterized by comprising a base part, a shell part and a seal gland; the sealing gland is fixed on a shaft platform of the pump main shaft through bolts and rotates together with the pump main shaft as a moving ring, the base part is installed on a sodium pump body as a static ring, the shell part is installed on the upper part of the base part, the base part and the shell part form a sealing cavity together with the pump main shaft, and the sealing gland is installed in the shell of the shell part and forms a sealing friction pair together with a sealing ring installed on a sealing support seat of the base part.

2. The sodium pump service seal of claim 1, wherein: the base part comprises a base, a corrugated pipe pneumatic assembly, a main shaft corrugated pipe, a spiral spring assembly, a sealing support seat, a sealing ring and a sealing compression ring; the base is fixed on the pump body by the bolt, and the bellows cover of main shaft is on the pump main shaft and be provided with the clearance between the two, and welds respectively on base and sealing support seat in both ends from top to bottom, is a whole with base and sealing support seat connection, the sealing ring is installed in the recess on the sealing support seat, and the bolt spiro union is used on sealing support seat and compresses tightly the sealing ring to sealed clamping ring, be provided with bellows pneumatic component and coil spring subassembly between sealing support seat and the base.

3. The sodium pump service seal of claim 2, wherein: the pneumatic assembly of the corrugated pipe is formed by welding a pneumatic spring corrugated pipe, an upper plug and a lower plug into a whole, the lower plug of the pneumatic assembly of the corrugated pipe is welded on the base, the lower plug of the pneumatic assembly of the corrugated pipe is provided with an air inlet and communicated with the air inlet arranged on the base, the inlet end of an air inlet of the base is connected with an external air source, and the upper plug is connected with the sealing support seat through a bolt.

4. The sodium pump service seal of claim 2, wherein: the spiral spring assembly comprises a supporting sleeve, a spring seat and a spring, wherein the supporting sleeve is fixedly installed on the base, the spring seat and the spring are installed in the supporting sleeve, the spring is sleeved on the spring seat, and the spring seat penetrates through a hole in the top of the sealing support seat and is fixed on the sealing support seat through a nut.

5. The sodium pump service seal of claim 1, wherein: the housing member includes a housing mounted on an upper portion of the base member and a support member mounted on an upper portion of the housing.

6. The sodium pump service seal of claim 5, wherein: the supporting part comprises a flange, a nut, a screw, a supporting part corrugated pipe and a supporting block; the supporting block is installed at the front end of the screw, the nut is sleeved at the tail of the screw, the flange is installed on the shell through bolts and sleeved with the nut, and the supporting component corrugated pipe is welded on the outer diameter of the screw.

7. The sodium pump service seal of claim 1, wherein: the contact surface of the sealing gland and the sealing ring is a conical surface, and the section of the sealing ring is rectangular.

8. The use method of the sodium pump service seal according to claim 1, characterized by comprising the following steps: