CN206234157U

CN206234157U - Double End packaging type pumps Hydrodynamic pressure type mechanical seal certainly

Info

Publication number: CN206234157U
Application number: CN201621262662.7U
Authority: CN
Inventors: 段衍筠; 麻亚飞; 严彦; 孙见君; 马晨波; 全琴; 牛韬
Original assignee: Nanjing Solideal Intelligent Control Equipment Co Ltd; Nanjing Forestry University
Current assignee: Nanjing Solideal Intelligent Control Equipment Co Ltd; Nanjing Forestry University
Priority date: 2016-11-22
Filing date: 2016-11-22
Publication date: 2017-06-09
Anticipated expiration: 2026-11-22

Abstract

The utility model proposes a kind of Double End packaging type from pumping Hydrodynamic pressure type mechanical seal, working medium is polluted solve the problems, such as the leakage of existing sodium pump interior circulation working medium and to block fluid lubrication that may be present the leaking into pump of oil, it is ensured that the safety and stability long-term operation of fast reactor.It is formed stationary ring, spring, sealing shell from pumping fluid seal structure etc. by rotating ring and rotating ring two ends and constituted；Bayonet fittings on rotating ring and axle sleeve, realize positioning rotating ring circumferential and axial；Holding screw is arranged on axle sleeve；Limiter is removably disposed between sealing shell or spring base and axle sleeve, to limit the relative axial position of axle sleeve and spring base, changes spring force so that the pressure between rotating ring and two stationary rings is identical；When rotating ring is rotated, the obstruction fluid that the external seal space that rotating ring, sealing shell etc. are surrounded is filled with combines duct and flows into the backward bending type fluid type groove opened on rotating ring end face under differential pressure action by axial-radial, is formed again and again from pumping circulation.

Description

Double-end-face integrated self-pumping fluid dynamic pressure type mechanical seal

Technical Field

The utility model belongs to the technical field of it is sealed, in particular to from pumping mechanical seal with fluid hybrid effect is applicable to the sealing between sodium-cooled fast reactor nuclear main pump shell and the pump shaft.

Background

Nuclear power is coming to a new round of high-speed development worldwide. Since the first prototype nuclear power plant was built in the world from the end of the 50 s to the beginning of the 60 s of the 20 th century, the development of nuclear power technology has gone through the first and second generations, and is currently advancing to the third generation and even the fourth generation. The reactors of the nuclear power plant are of various types and can be divided into a light water reactor (including a pressurized water reactor and a boiling water reactor), a heavy water reactor, a graphite gas cooled reactor, a fast breeder reactor and the like. According to the thermodynamic system, the nuclear power station has 3 types, namely a single-loop system, a double-loop system and a three-loop system. In the single loop system, working medium directly enters a steam turbine or a gas turbine from a reactor, such as a boiling water reactor and a high-temperature gas cooled reactor adopting a helium turbine direct circulation mode; in the double-loop system, the heat of the reactor is transferred from a primary loop to a secondary loop working medium through a steam generator to generate steam, and then a steam turbine is pushed to do work, and a pressurized water reactor and a high-temperature gas cooled reactor adopting a steam turbine circulation mode belong to the type; the three-circuit system is more complex, and the main reactor type is a fast breeder reactor. Regardless of the thermodynamic system and the reactor type, the coolant is required to take heat generated by nuclear fission in the reactor core out to cool the reactor core and perform a subsequent power generation process, and the cooling loop is a loop system which is a core system of the reactor of the nuclear power station.

The coolant circulating in the primary loop system of the reactor often has the characteristics of high temperature, high pressure, strong radioactivity and the like, and the leakage of the coolant must be strictly controlled. Because rotating equipment such as a pump/fan/compressor/steam turbine/gas turbine exists in a loop circulating system, in order to solve the problem of coolant sealing brought by the rotating equipment, 2 schemes are generally adopted in engineering: firstly, shaft seal type equipment, namely high-reliability nuclear-grade mechanical seal, is adopted; secondly, the driving motor of the equipment such as the pump is integrally arranged in a loop pressure shell, so that the dynamic seal with leakage risk is converted into a static seal with zero leakage, and an external auxiliary system is greatly simplified, but the technical difficulty is transferred to the equipment or parts such as the motor, the bearing and the like by the scheme. For example, for a pressurized water reactor, a coolant pump (nuclear main pump) motor must adopt a shielding type or a wet stator type, and a main pump bearing must adopt a water-lubricated bearing in all; for a high-temperature gas cooled reactor of steam turbine circulation, oil-free bearings such as electromagnetic bearings are needed for a main shaft bearing of a helium fan. Because the motor and the bearing have high technical difficulty and high manufacturing cost, and the problems of working efficiency and reliability are difficult to solve particularly under the conditions of high power and large size, a loop system applying mechanical seal still occupies a leading position at present.

As a fourth generation reactor, a fast reactor, namely a fast neutron breeder, directly uses fast neutrons generated by fission to initiate nuclear fission chain reaction without using a moderator, and can breed nuclear fuel, fully utilize uranium resources and greatly reduce long-life nuclides in nuclear waste. Fast reactor coolant needs to have the properties of good heat transfer performance and no moderation of neutrons, and is mainly liquid metal and helium at present. The primary loop system of the sodium-cooled fast reactor consists of a reactor core, a main pump (primary sodium pump), a heat exchanger, a main pipeline and other parts. Compared with the mechanical seal of a primary loop main circulating pump of other reactors, the mechanical seal of the sodium-cooled fast reactor nuclear main pump has the advantages of low working condition pressure (571kPa) and low temperature (70 ℃) and is beneficial to realizing the seal. However, the sodium has strong activity and can explode when meeting water or air, so the reliability requirement of the sodium pump sealing is high, the design needs to strictly ensure zero leakage of liquid sodium, and meanwhile, the short-time reliable sealing under the action of earthquake load is also guaranteed so as to facilitate shutdown and core heat discharge.

Fig. 1 is a schematic diagram of a primary-loop sodium pump of a sodium-cooled fast reactor prototype reactor (PFBR) (king yuming, huangweifeng, li immortal. a loop of a nuclear power plant is mechanically sealed, and the journal of tribology 2011,31 (4): 408-. The upper part of the free liquid level of liquid sodium in the shell of the sodium pump is filled with argon, and a mechanical seal is arranged at a certain height away from the liquid level of the sodium. The design form avoids direct contact between sealing and liquid sodium with the temperature as high as 400-500 ℃, and eliminates a plurality of harsh limitations on materials, structures and the like, so that the conventional mechanical sealing design can be used.

According to the prior art, a sodium pump references the 3 rd-level sealing of a light water reactor (comprising a pressurized water reactor and a boiling water reactor), a heavy water reactor and a graphite gas cooled reactor, namely, the sealing is realized by adopting a double-end mechanical seal blocked by lubricating oil or a dry gas seal blocked by gas. For the double-end mechanical seal blocked by the lubricating oil, the pressure of the blocked lubricating oil is usually kept higher than that of the working medium gas so as to prevent the protective argon from leaking into the blocked fluid, and an oil slinger is arranged on a shaft sleeve at the lower part of the working medium gas side mechanical seal so as to ensure that the blocking lubricating oil with higher pressure can flow into a liquid collecting barrel through the oil slinger and a liquid collecting channel when leaking into a pump cavity and does not pollute sodium liquid. For dry gas seals that employ gas block, the blocking gas pressure is typically maintained above the pressure of the working fluid gas to prevent the leakage of protective argon gas into the blocking gas.

However, with a dry gas seal that is gas-blocked, the auxiliary system is required to provide a clean blocking gas to maintain non-contact operation of the dry gas seal during operation; meanwhile, blocking gas with pressure higher than that of working medium gas can leak into the pump cavity through the gap of the sealing end face, so that blocking gas loss, protection argon pollution and pressure rise are caused. Particularly, after the sealing end face is instantaneously separated under the action of abnormal axial loads such as earthquakes and the like, when a large amount of lubricating oil leaks into the oil slinger, the liquid collecting pore channel cannot flow through in time, and the lubricating oil flows into the pump cavity along the air passage to form sodium liquid pollution, so that the safety of the sodium-cooled fast reactor is seriously threatened.

Disclosure of Invention

The utility model aims at providing a bi-polar face fluid dynamic static pressure is from pumping mechanical seal for sodium-cooled fast reactor nuclear main pump to solve the leakage of current sodium pump inner loop working medium and block the problem that fluid lubricating oil probably exists leak into the pump in and pollute the working medium, guarantee the safe and stable long-period running of fast reactor.

The technical scheme of the utility model is that:

a double-end-face integrated self-pumping hydrodynamic mechanical seal is arranged between a housing of a sodium pump and a pump shaft 2 and comprises a moving ring 10, an O-shaped ring 9 for the moving ring, static rings 8 and 12, O-shaped rings 7 and 13 for the static rings, springs 6 and 15, spring seats 5 and 14, a seal shell 16, a shaft sleeve 1, an O-shaped ring 17 for the shaft sleeve, a limiter 4, a pin 11 and a set screw 3,

the movable ring 10, the static rings 8 and 12 on the two sides of the movable ring, and the spring seats 5 and 14 are all sleeved on the shaft sleeve 1 in a penetrating manner; the movable ring 10 is hermetically connected with the shaft sleeve 1 by an O-shaped ring 9; the upper end and the lower end of the moving ring 10 are moving ring sealing end faces, each moving ring sealing end face is matched with 1 static ring, and the outer circular faces of the static rings 8 and 12 are in sealing connection with the sealing shell 16 through O-shaped rings 7 and 13; the other end face of the static ring is respectively supported with more than 3 springs, the other ends of the springs act on the spring seats 5 and 14, the spring seats 5 and 14 are connected with the sealing shell, and a certain end face specific pressure is obtained between the sealing end face of the dynamic ring and the end face of the static ring; the movable ring 10 is matched with a pin 11 on the shaft sleeve through a pin hole which is positioned at the lower part of the movable ring and is radially closed and axially opened, so that the circumferential positioning of the movable ring 10 is realized, and the pin 11 is kept in contact with the bottom of the pin hole and the axial positioning of the movable ring 10 is realized at the same time; the set screw 3 arranged on the shaft sleeve is used for fixing the relative position of the shaft sleeve 1 and the pump shaft 2; the limiter 4 is detachably arranged between the seal shell 16 or the spring seats 5 and 14 and the shaft sleeve 1 and is used for limiting the axial relative position of the shaft sleeve 1 and the seal shell 16 or the spring seats 5 and 14 so as to change the elastic force of the springs supporting the two static rings, so that the pressure between the sealing end surfaces at the two ends of the dynamic ring and the two static rings is the same;

the static ring is enclosed into an outer sealing space by the O-shaped rings 7 and 13, the dynamic ring 10 and the sealing shell 16, and a blocking fluid is filled into the outer sealing space;

the sealing end face of the movable ring matched with the static rings 8 and 12 is divided into a groove area and a sealing dam 37, the groove area is distributed on the outer side part of the end face, and the sealing dam 37 is distributed on the inner side part of the end face; more than 3 groups of backward bending type fluid grooves 39 are arranged in the groove area, and sealing end faces between the backward bending type fluid grooves 39 form a sealing weir; the groove areas and the sealing dams 37 on the sealing end surfaces of the movable ring at the upper end and the lower end of the movable ring 10 are symmetrically arranged with the middle section M-M of the movable ring;

the backward bending type fluid type groove 39 comprises a slope groove 32 and a flat groove 33, wherein the slope groove 32 is positioned at the large radius part of the end surface of the moving ring, and the flat groove 33 is positioned at the small radius part of the end surface of the moving ring;

the outlet of the backward bent fluid type groove 39 is positioned at the outer diameter of the sealing end face of the moving ring, the inlet 31 is positioned in the middle of the sealing surface of the moving ring 10, and the inlet 31 of the backward bent fluid type groove 39 is communicated with the outer sealing space through the axial and radial combined pore passage 30 on the moving ring 10;

two side groove walls of the backward bending type fluid groove 39 are provided, one side is a working surface 34, and the other side is a non-working surface 35;

when the moving ring rotates, the blocking fluid in the backward-bent fluid type groove 39 is accelerated into high-speed fluid by the working surface of the backward-bent fluid type groove 39, the high-speed fluid flows along the non-working surface 35 to the outer diameter side of the moving ring 10 under the action of centrifugal force and is pumped into the outer sealing space, a low-pressure area is formed at the inlet 31 of the backward-bent fluid type groove 39, and the blocking fluid in the outer sealing space flows into the backward-bent fluid type groove 39 through the axial and radial combined pore passage 30, communicated with the outer sealing space, on the moving ring 10 under the action of differential pressure, so that primary self-pumping circulation is formed;

the working surface 34 of the backward-bent fluid groove 39 is accelerated to be high-speed blocking fluid, and in the process of being pumped out of the backward-bent fluid groove 39, along with the gradual increase of the flow cross-sectional area of the backward-bent fluid groove 39, the flow speed is reduced, the pressure is increased, and the opening force for separating the movable ring 10 and the static rings 8 and 12 is formed.

The pin 11 contacts with the bottom of the pin hole to realize the axial positioning of the movable ring 10, so that the weight of the movable ring is supported by the pin, the weight of the movable ring cannot be transmitted to the stationary ring at the lower part, and the upper spring supporting the stationary ring at the upper part can have certain compression amount. If no pin is used for axially positioning the movable ring 10, the lower spring for supporting the lower static ring needs to bear the weight of 2 static rings and the weight of one movable ring, and the pressure between the sealing end surfaces at the two ends of the movable ring and the two static rings cannot be the same. In the self-pumping circulation process, on one hand, self-lubrication of mechanical seal is realized; on the other hand, the fluid is blocked in the outer sealing space to continuously circulate between the sealing surfaces, so that the frictional heat between the sealing surfaces is taken away in time, and the self-flushing of the seal is realized; the centrifugal force is used for increasing the power of the fluid flowing to the outer side of the sealing surface of the moving ring 10 and reducing the leakage rate of the fluid flowing to the inner side of the sealing surface of the moving ring 10; in particular, the centrifugal force causes the solid particles-containing choked fluid entering the backward curved fluid groove 39 to separate from the matrix, wherein the dense solid particles acquire a larger centrifugal force and are pumped out with the fluid to be re-delivered into the outer sealing space without entering the sealing dam 37 area, thereby avoiding abrasive wear between the sealing surfaces.

As a further improvement, a working medium cavity is enclosed by the O-shaped ring 17 for the shaft sleeve, the shaft sleeve 1, the static ring 12 at the lower part, the O-shaped ring 13 for the static ring, the moving ring 10, the shell of the sodium pump and the pump shaft 2, the lower part in the working medium cavity is high-temperature metal sodium liquid, and the upper part is protective argon; the blocking fluid in the outer sealing space is also argon, and the pressure of the blocking fluid is not less than the pressure of the argon in the working medium cavity. Because the pressure of the blocking fluid is not less than the pressure of the argon in the working medium cavity, the argon in the working medium cavity cannot enter the outer sealing space through the leakage of the sealing end face between the static ring and the dynamic ring. Even if the dynamic and static rings are separated instantly under the action of earthquake load, the blocking fluid can enter the working medium cavity only by leaking through the sealing end face between the static ring and the dynamic ring, but the blocking fluid is the same as the upper medium in the working medium cavity, so that the influence on the work of the nuclear main pump can not be caused even if the blocking fluid enters the working medium cavity.

As a further improvement, the number and the structure of springs supporting the two stationary rings are the same, and the rigidity of the springs is K; the two static rings have the same structure and the weight is GJ; the compression length delta x2 of the spring supporting the static ring at the lower part of the dynamic ring and the compression length delta x1 of the spring supporting the static ring at the upper part of the dynamic ring satisfy that: and delta x 2-delta x1 is 2GJ/K, so that the pressure between the sealing end faces at the two ends of the movable ring and the two static rings is the same.

When the double-end-face fluid dynamic-static pressure mechanical seal works, a shaft sleeve is fixed on a pump shaft 2 through a set screw 3, and a moving ring is axially and circumferentially positioned on the shaft sleeve through a pin 11, so that the position of the moving ring relative to the pump shaft 2 is fixed.

Because the static ring on the upper part of the rotating ring stretches the spring by the gravity thereof, and the static ring on the lower part of the rotating ring compresses the spring by the gravity thereof, the pressure of the upper static ring and the lower static ring on the sealing end surface of the rotating ring is different under the same spring compression amount, the abrasion loss of 2 sealing pairs (the contact surface of the rotating ring and the static ring) in the working process is different, the sealing service life of the double end surfaces is shortened, and the elasticity (or the compression length) of the upper spring and the lower spring for supporting the upper static ring and the lower static ring is required to be adjusted.

For the movable ring, the pressure Y1 of the upper static ring on the movable ring, the pressure Y2 of the lower static ring on the movable ring, the gravity GD of the movable ring and the supporting force ZD of the pin on the movable ring are received; y1+ GD ═ Y2+ ZD. If the pressure Y1 of the upper static ring to the dynamic ring is equal to the pressure Y2 of the lower static ring to the dynamic ring, the supporting force ZD of the pin to the dynamic ring should be equal to the gravity GD of the dynamic ring.

For the upper stationary ring, Y1 ═ K Δ x1+ GJ; for the lower stationary ring, K Δ x1 ═ Y2+ GJ. If Y1 ═ Y2, i.e. K Δ x1+ GJ ═ K Δ x2-GJ, Δ x2- Δ x1 ═ 2 GJ/K.

The molded lines of the two side groove walls of the backward bending type fluid groove 39 are helical lines.

The spiral lines of the molded lines of the groove walls on the two sides of the backward bending type fluid groove 39 have the same spiral angle.

The spiral angles of the spiral lines of the groove wall molded lines on the two sides of the backward bending type fluid groove 39 are different, and the spiral angle of the working surface 34 is smaller than that of the non-working surface 35.

The spiral lines of the molded lines of the groove walls at the two sides of the backward bending type fluid groove 39 are tangent to the circular hole of the inlet 31.

The cross section of the joint of the axial and radial combined pore passage 30 on the rotating ring 10 and the outer circular surface of the rotating ring 10 is a wedge-shaped opening. In the above double-end-face fluid dynamic-static pressure mechanical seal, the inlet 31 of the backward-bending fluid type groove 39 is communicated with the outer sealing space through the axial and radial combined pore passage 30 on the moving ring 10; when the moving ring rotates, the blocking fluid in the outer sealing space flows into the backward-bent fluid groove 39 through the axial and radial combined pore passage 30 communicated with the outer sealing space on the moving ring 10 under the action of pressure difference, and a one-time self-pumping cycle is formed.

As another technical solution of the present invention, the inlet 31 of the backward bending type fluid groove 39 is communicated with a circular ring groove 36 disposed in the middle of the sealing surface of the rotating ring 10 or the stationary ring 8, 12, and the circular ring groove 36 is communicated with the outer sealing space through being located on the rotating ring or the stationary ring; when the moving ring rotates, blocking fluid in the outer sealing space flows into the backward-bending fluid groove 39 through the axial and radial combined pore passage 30 and the circular ring groove 36 which are communicated with the outer sealing space on the static ring under the action of pressure difference, and a primary self-pumping circulation is formed.

The circular ring groove 36 has the functions of collecting self-lubricating and self-flushing media and preventing the non-uniformity of pumped media and the occurrence of cavitation due to untimely fluid replenishment at the inlet 31 of the backward curved fluid groove 39.

The groove areas on the sealing end faces of the movable ring at the upper end and the lower end of the movable ring 10 and the sealing dams 37 are symmetrically arranged with the middle section M-M of the movable ring, so that the structures of 2 sealing pairs (the contact surfaces of the movable ring and the static ring) are the same, the abrasion loss of the two sealing pairs is the same, and the service life is prolonged. The section M-M of the movable ring refers to a cross section which is perpendicular to the axis of the movable ring and divides the movable ring into equal parts in the axial direction.

The beneficial effects of the utility model.

A from fluid dynamic pressure type mechanical seal of pumping, have following several advantages:

the sealing structure has excellent sealing performance, realizes zero leakage, and is suitable for sealing the sodium-cooled fast reactor nuclear main pump. The O-shaped ring 9 for the movable ring, the O-shaped rings 7 and 13 for the static ring and the O-shaped ring 17 for the shaft sleeve prevent the leakage of argon in the working medium cavity; because the blocking fluid pressure is not less than the pressure of the argon in the working medium cavity, and the self-pumping circulation of the blocking fluid is performed once and again, the leakage of the argon at the sealing end face between the driven ring and the static ring in the working medium cavity is effectively prevented.

② when the rotating ring is rotatory, different mass particle produce different centrifugal force, make the utility model discloses a mechanical seal has the automatic clear solid particle function, can avoid the abrasive particle wearing and tearing of sealed dam to need not provide extra filtration auxiliary system.

And thirdly, the application range is wide, and the sealing device can be used for sealing gas and liquid.

The unique self-lubricating and self-cooling flushing functions ensure the stability and durability of the sealing work.

And fifthly, blocking fluid in a static state and directly injecting the fluid between the sealing surfaces of the dynamic ring and the static ring, eliminating solid friction between the sealing surfaces of the dynamic ring and the static ring at the moment of starting and rapidly forming a fluid film at the moment of starting.

And the assembly structure is quick and convenient to assemble. Because the utility model discloses have stopper 4 that can dismantle, so can be before the installation uses the product (seal shell 16, rotating ring 10, quiet ring 8, 12, spring holder 5, 14, axle sleeve 1, pin 11, holding screw 3 etc.) assembly moulding, form the mechanical seal of a "collection dress formula". When the sodium pump is installed, the sodium pump is sleeved with the first spring seat, the spring seat 15 at the lower part of the sodium pump is fixed with the shell of the sodium pump, the set screw 3 is screwed on the pump shaft, and the limiter 4 is detached.

Drawings

Fig. 1 is a schematic diagram of a primary loop sodium pump of a sodium-cooled fast reactor prototype reactor (PFBR).

Fig. 2 is a schematic structural view of an axial section of a self-pumping fluid dynamic pressure type mechanical seal before installation, wherein a backward bending type fluid groove and an axial and radial combined pore passage are formed in a movable ring.

Fig. 3 is a schematic structural view of the cross section of a self-pumping fluid dynamic pressure type mechanical seal with a backward-curved fluid groove and an axial and radial combined pore passage arranged on a moving ring.

Fig. 4 is a schematic structural view of an axial section of a self-pumping hydrodynamic mechanical seal before installation, wherein a backward-bending fluid groove is formed in a moving ring, and an axial and radial combined pore passage is formed in a stationary ring. (the circular ring groove can be opened on the movable ring and also can be opened on the static ring)

Fig. 5 is a schematic structural view of a shaft section of a self-pumping hydrodynamic mechanical seal with a backward-curved fluid groove on a moving ring and an axial-radial combined hole on a stationary ring. (the circular ring groove can be opened on the movable ring and also can be opened on the static ring)

Fig. 6 is a schematic end view of the moving ring with backward-curved fluid grooves and axial and radial combined ducts.

Fig. 7 is a schematic end view of the rotating ring with the backward-curved fluid-type groove and the circular ring groove.

Fig. 8 is a schematic end view of a stationary ring with axially and radially combined ports, which is similar to fig. 7.

Fig. 9 is a schematic end view of the movable ring with the backward-bending fluid-type groove.

Fig. 10 is a schematic end view of a stationary ring with circular ring grooves and axial and radial combined ducts, which is matched with fig. 9.

Wherein,

r1-inner radius of sealing end face between the dynamic ring and the static ring;

r2-the outer radius of the sealing end face where the moving ring and the static ring are mutually attached;

radius of Rp-shaped groove step

Radius of Ro-shaped groove inlet hole

Radius of Rk-groove inlet hole

R3-groove inlet ring groove inner radius

R4-groove inlet ring groove external radius

G-pumping direction of fluid type groove

w-rotation direction of moving ring

The pump comprises a shaft sleeve 1, a pump shaft 2, a set screw 3, a limiter 4, a spring seat 5, a spring 6, a static ring O-shaped ring 7, a static ring 8, a dynamic ring O-shaped ring 9, a dynamic ring 10, a pin 11, a static ring 12, a static ring O-shaped ring 13, a spring seat 14, a spring 15, a sealing shell 16, a shaft sleeve O-shaped ring 17, an axial and radial combined duct 30, an inlet 31, a slope groove 32, a flat groove 33, a working surface 34, a non-working surface 35, a circular ring groove 36, a sealing dam 37, a backward bent fluid groove 39, a mechanical seal 40, a thrust bearing 41, a pump shaft 42, a guide bearing 43, an impeller 44 and a dynamic ring middle section M-M.

Detailed Description

The following describes embodiments of the present invention in detail with reference to the drawings and three examples.

The same construction of the three embodiments will be explained.

Referring to fig. 2 and 3 or fig. 4 and 5, the three embodiments are all double-end face cartridge-type self-pumping hydrodynamic mechanical seals, and are composed of a moving ring 10, an O-ring 9 for the moving ring, stationary rings 8 and 12, O-rings 7 and 13 for the stationary rings, springs 6 and 15, spring seats 5 and 14, a seal housing 16, a shaft sleeve 1, an O-ring 17 for the shaft sleeve, a stopper 4, a pin 11, a set screw 3 and the like.

Specifically, the dynamic ring 10, the static rings 8 and 12 at the two ends of the dynamic ring, and the spring seats 5 and 14 are sleeved on the shaft sleeve 1 in a penetrating way; the movable ring 10 is hermetically connected with the shaft sleeve 1 by an O-shaped ring 9; the upper end and the lower end of the moving ring 10 are moving ring sealing end faces, each moving ring sealing end face is matched with 1 static ring, and the outer circular faces of the static rings 8 and 12 are in sealing connection with the sealing shell 16 through O-shaped rings 7 and 13; more than 3 springs are respectively supported on the other end face of the static ring, the other ends of the springs act on the spring seats 5 and 14, the spring seats 5 and 14 are fixedly connected to the upper part and the lower part of the sealing shell through bolts, and a certain end face specific pressure is obtained between the sealing end face of the dynamic ring and the end face of the static ring; the movable ring 10 is matched with a pin 11 on the shaft sleeve through a pin hole which is positioned at the lower part of the movable ring and is radially closed and axially opened, so that the circumferential positioning of the movable ring 10 is realized, and the pin 11 is kept in contact with the bottom of the pin hole and the axial positioning of the movable ring 10 is realized at the same time; the set screw 3 is arranged on the shaft sleeve.

The two static rings have the same structure, and the weight is GJ. The number of the springs 15 supporting the static ring positioned at the lower part of the dynamic ring is the same as that of the springs 6 supporting the static ring positioned at the upper part of the dynamic ring, the rigidity is K, and the springs are uniformly distributed in the circumferential direction of the static ring.

The limiter 4 is a split-type limiting ring consisting of two semicircular limiting half rings, the limiting ring is detachably connected with the upper surface of the upper spring seat 5 through a screw, and the inner side of the limiting ring extends into a limiting groove formed in the shaft sleeve 1, so that the shaft sleeve 1, the sealing shell 16 and the spring seats 5 and 14 are axially kept at a certain position. In this position, the compression length Δ x2 of the spring 15 and the compression length Δ x1 of the spring 6 supporting the stationary ring located above the moving ring satisfy: and delta x 2-delta x1 is 2GJ/K, so that the pressure between the sealing end faces at the two ends of the moving ring and the two static rings is the same.

The static ring is enclosed by the O-shaped rings 7 and 13, the dynamic ring 10 and the sealing shell 16 to form an external sealing space, and argon serving as blocking fluid is filled in the external sealing space.

Referring to fig. 6, 7 and 9, the sealing end surface of the moving ring, which is matched with the stationary rings 8 and 12, is divided into a groove area and a sealing dam 37, the groove area is distributed on the outer side part of the end surface, and the sealing dam 37 is distributed on the inner side part of the end surface; more than 3 groups of backward bending type fluid grooves 39 are arranged in the groove area, and sealing end faces between the backward bending type fluid grooves 39 form a sealing weir; the groove areas on the sealing end faces of the movable ring at the upper end and the lower end of the movable ring 10 and the sealing dam 37 are symmetrically arranged in a middle section M-M of the movable ring, which is perpendicular to the axis of the movable ring and passes through the middle position of the movable ring.

when the moving ring rotates, the blocking fluid in the backward-bent fluid type groove 39 is accelerated into high-speed fluid by the working surface of the backward-bent fluid type groove 39, the high-speed fluid flows along the non-working surface 35 to the outer diameter side of the moving ring 10 under the action of centrifugal force and is pumped into the outer sealing space, a low-pressure area is formed at the inlet 31 of the backward-bent fluid type groove 39, and the blocking fluid in the outer sealing space flows into the backward-bent fluid type groove 39 through flow channels such as the axial and radial combined pore channels 30 communicated with the outer sealing space on the moving ring 10 or the static rings 8 and 12 under the action of differential pressure, so that a primary self-pumping circulation is formed;

The double-end-face integrated self-pumping fluid dynamic pressure type mechanical seal is an integrated mechanical seal and can be quickly installed on site after being assembled in a factory. During installation, the shaft sleeve 1 is sleeved on the pump shaft 2 of the sodium pump in a penetrating mode, the spring seat 15 at the lower portion is fixed with the shell of the sodium pump in a sealing mode, and the set screw 3 is screwed on the pump shaft. At this time, the positions of the shaft sleeve and the spring seat 15 (including the sealing shell 16, the spring seat 4 and the like) are fixed, so that the position limiter 4 is detached again, the relative position of the shaft sleeve and the spring seat is not changed, the compression length delta x2 of the spring 15 and the compression length delta x1 of the spring 6 are ensured to be at the set length when the device leaves the factory, the pressure between the sealing end surfaces at the two ends of the moving ring in work and the pressure between the two stationary rings are the same, and the service life is prolonged.

When in use, the O-shaped ring 17 for the shaft sleeve, the shaft sleeve 1, the static ring 12 at the lower part, the O-shaped ring 13 for the static ring, the moving ring 10, the shell of the sodium pump and the pump shaft 2 enclose a working medium cavity, the lower part in the working medium cavity is high-temperature metal sodium liquid, and the upper part is protective argon; the pressure of the argon in the outer sealing space is not less than that of the argon in the working medium cavity. Because the pressure of the blocking fluid is not less than the pressure of the argon in the working medium cavity, the argon in the working medium cavity cannot enter the outer sealing space through the leakage of the sealing end face between the static ring and the dynamic ring. Even if the dynamic and static rings are separated instantly under the action of earthquake load, the blocking fluid can enter the working medium cavity only by leaking through the sealing end face between the static ring and the dynamic ring, but the blocking fluid is the same as the upper medium in the working medium cavity, so that the influence on the work of the nuclear main pump can not be caused even if the blocking fluid enters the working medium cavity.

The different structures of the embodiments will be described below.

The main differences between the three embodiments are: whether the axial and radial combined pore canal 30 is opened on the moving ring or the static ring, whether a circular ring groove is opened on the moving ring or the static ring. The following are described separately.

Example 1: double-end-face integrated self-pumping hydrodynamic mechanical seal with axial and radial combined pore channel on moving ring

Referring to fig. 2, 3 and 6, inlets 31 of backward-bent fluid grooves 39 at the upper end and the lower end of the rotating ring are communicated with the outer sealing space through axial and radial combined ducts 30 formed in the rotating ring 10. When the moving ring rotates, blocking fluid such as argon in the outer sealing space flows into the backward-bending type fluid groove 39 through the axial and radial combined pore passage 30 on the moving ring 10 under the action of pressure difference, and a self-pumping cycle is formed once and again.

Example 2: double-end-face integrated self-pumping fluid dynamic pressure type mechanical seal with circular ring groove on moving ring and axial and radial combined pore channel on static ring

Referring to fig. 4, 5, 7 and 8, the inlet 31 of the backward-curved fluid groove 39 on the rotating ring is communicated with a circular ring groove 36 arranged in the middle of the sealing surface of the rotating ring 10. One end of the axial and radial combined pore canal 30 opened on the static ring is communicated with the outer sealing space, and the other end is opposite to the circular ring groove 36 in the axial direction.

When the moving ring rotates, blocking fluid such as argon in the outer sealing space flows into the backward-bending type fluid groove 39 through the axial and radial combined pore passage 30 on the static ring and the circular ring groove 36 on the moving ring under the action of pressure difference, and a primary self-pumping circulation is formed.

Example 3: double-end-face integrated self-pumping hydrodynamic mechanical seal with circular ring groove and axial and radial combined pore passage formed in stationary ring

Referring to fig. 9 and 10 (refer to fig. 4 and 5), the inlet 31 of the backward-bent fluid groove 39 on the moving ring is communicated with a circular groove 36 formed in the middle of the sealing surface of the stationary ring, and the circular groove 36 is communicated with the outer sealing space through an axial and radial combined hole passage 30 formed in the stationary ring. When the moving ring rotates, blocking fluid such as argon in the outer sealing space flows into the backward-bending type fluid groove 39 through the axial and radial combined pore passage 30 on the static ring and the circular ring groove 36 on the static ring under the action of pressure difference, and a primary self-pumping circulation is formed.

Claims

1. The utility model provides a bi-polar face collection dress formula is from pumping fluid dynamic pressure type mechanical seal, sets up between casing and pump shaft (2) of sodium pump, by rotating ring (10), O shape circle (9) for the rotating ring, quiet ring (8, 12), O shape circle (7, 13) for the quiet ring, spring (6, 15), spring holder (5, 14), seal housing (16), axle sleeve (1), O shape circle (17) for the axle sleeve, stopper (4), pin (11) and holding screw (3) are constituteed, characterized by:

the movable ring (10) and the static rings (8, 12) and the spring seats (5, 14) on the two sides of the movable ring are sleeved on the shaft sleeve (1) in a penetrating way; the movable ring (10) is hermetically connected with the shaft sleeve (1) by an O-shaped ring (9); the upper end and the lower end of the movable ring (10) are movable ring sealing end faces, each movable ring sealing end face is matched with 1 static ring, and the outer circular faces of the static rings (8 and 12) are hermetically connected with the sealing shell (16) through O-shaped rings (7 and 13); more than 3 springs are respectively supported on the other end face of the static ring, the other ends of the springs act on spring seats (5 and 14), the spring seats (5 and 14) are connected with the sealing shell, and a certain end face specific pressure is obtained between the sealing end face of the movable ring and the end face of the static ring; the movable ring (10) is matched with a pin (11) on the shaft sleeve through a pin hole which is positioned at the lower part of the movable ring and is radially closed and axially opened, so that the circumferential positioning of the movable ring (10) is realized, and the pin (11) is kept in contact with the bottom of the pin hole while the axial positioning of the movable ring (10) is realized; the set screw (3) arranged on the shaft sleeve is used for fixing the relative position of the shaft sleeve (1) and the pump shaft (2); the limiter (4) is detachably arranged between the sealing shell (16) or the spring seats (5 and 14) and the shaft sleeve (1) and is used for limiting the axial relative position of the shaft sleeve (1) and the sealing shell (16) or the spring seats (5 and 14) so as to change the elastic force of the springs supporting the two static rings, so that the pressure between the sealing end surfaces at the two ends of the movable ring and the pressure between the two static rings are the same;

the static ring is enclosed into an outer sealing space by the O-shaped rings (7, 13), the dynamic ring (10) and the sealing shell (16), and a blocking fluid is filled into the outer sealing space;

the sealing end face of the movable ring matched with the static rings (8 and 12) is divided into a groove area and a sealing dam (37), the groove area is distributed on the outer side part of the end face, and the sealing dam (37) is distributed on the inner side part of the end face; more than 3 groups of backward bending type fluid grooves (39) are arranged in the groove area, and sealing end faces between the backward bending type fluid grooves (39) form a sealing weir; the groove areas on the sealing end surfaces of the movable ring at the upper end and the lower end of the movable ring (10) and the sealing dam (37) are symmetrically arranged by the middle section (M-M) of the movable ring;

the backward bending type fluid type groove (39) comprises a slope groove (32) and a flat groove (33), the slope groove (32) is positioned at the large radius part of the end surface of the moving ring, and the flat groove (33) is positioned at the small radius part of the end surface of the moving ring;

the outlet of the backward bent fluid type groove (39) is positioned at the outer diameter of the sealing end face of the moving ring, the inlet (31) is positioned in the middle of the sealing surface of the moving ring (10), and the inlet (31) of the backward bent fluid type groove (39) is communicated with the outer sealing space through an axial and radial combined pore passage (30) on the moving ring (10);

two side groove walls of the backward bending type fluid type groove (39), one side is a working surface (34), and the other side is a non-working surface (35);

when the moving ring rotates, the blocking fluid in the backward-bent fluid type groove (39) is accelerated into high-speed fluid by the working surface of the backward-bent fluid type groove (39), flows to the outer diameter side of the moving ring (10) along the non-working surface (35) under the action of centrifugal force and is pumped into the outer sealing space, a low-pressure area is formed at the inlet (31) of the backward-bent fluid type groove (39), and the blocking fluid in the outer sealing space flows into the backward-bent fluid type groove (39) through an axial and radial combined pore passage (30) which is arranged on the moving ring (10) and is communicated with the outer sealing space under the action of differential pressure, so that a primary self-pumping circulation is formed;

the working surface (34) accelerated by the backward-bent fluid groove (39) is high-speed blocked fluid, and in the process of being pumped out of the backward-bent fluid groove (39), along with the gradual increase of the flow cross section area of the backward-bent fluid groove (39), the flow speed is reduced, the pressure is increased, and the opening force for separating the movable ring (10) and the static rings (8 and 12) is formed.

2. The double-ended cartridge-type self-pumping hydrodynamic mechanical seal of claim 1, wherein: the shaft sleeve is provided with an O-shaped ring (17), the shaft sleeve (1), a static ring (12) at the lower part and a working medium cavity enclosed by the O-shaped ring (13), a moving ring (10), a shell of the sodium pump and a pump shaft (2) for the static ring, the lower part in the working medium cavity is high-temperature metal sodium liquid, and the upper part in the working medium cavity is protective argon; the blocking fluid in the outer sealing space is also argon, and the pressure of the blocking fluid is not less than the pressure of the argon in the working medium cavity.

3. The double-ended cartridge-type self-pumping hydrodynamic mechanical seal of claim 1, wherein: the number and the structure of the springs for supporting the two stationary rings are the same, and the rigidity of the springs is K; the two static rings have the same structure and the weight is GJ; the compression length delta x2 of the spring supporting the static ring at the lower part of the dynamic ring and the compression length delta x1 of the spring supporting the static ring at the upper part of the dynamic ring satisfy that: and delta x 2-delta x1 is 2GJ/K, so that the pressure between the sealing end faces at the two ends of the movable ring and the two static rings is the same.

4. The double-ended cartridge-type self-pumping hydrodynamic mechanical seal of claim 1, wherein: the molded lines of the groove walls on the two sides of the backward bending type fluid groove (39) are helical lines.

5. The double-ended cartridge-type self-pumping hydrodynamic mechanical seal of claim 4, wherein: the spiral lines of the molded lines of the groove walls on the two sides of the backward bending type fluid groove (39) have the same spiral angle.

6. The double-ended cartridge-type self-pumping hydrodynamic mechanical seal of claim 4, wherein: the spiral angles of the spiral lines of the groove wall molded lines on the two sides of the backward bending type fluid groove (39) are different, and the spiral angle of the working surface (34) is smaller than that of the non-working surface (35).

7. The double-ended cartridge-type self-pumping hydrodynamic mechanical seal of claim 4, wherein: the spiral lines of the molded lines of the groove walls at the two sides of the backward bending type fluid groove (39) are tangent to the round hole of the inlet (31).

8. The double-ended cartridge-type self-pumping hydrodynamic mechanical seal of claim 5, wherein: the cross section of the joint of the axial and radial combined pore canal (30) on the moving ring (10) and the outer circular surface of the moving ring (10) is a wedge-shaped opening (38).

9. The double-ended cartridge-type self-pumping hydrodynamic mechanical seal of claim 1, wherein: an inlet (31) of the backward bending type fluid groove (39) is communicated with a circular ring groove (36) arranged in the middle of the sealing surface of the moving ring (10) or the static rings (8, 12), and the circular ring groove (36) is at least communicated with the outer sealing space through the circular ring groove positioned on the static ring; when the rotating ring rotates, blocking fluid in the outer sealing space flows into the backward-bent fluid groove (39) through the axial and radial combined pore canal (30) and the circular ring groove (36) which are arranged on the static ring and communicated with the outer sealing space under the action of pressure difference, and a primary and secondary self-pumping circulation is formed.