CN213271031U

CN213271031U - Quick-repair high-temperature and high-pressure-difference valve with preposed anti-cavitation function

Info

Publication number: CN213271031U
Application number: CN202022340688.1U
Authority: CN
Inventors: 邓劲才
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-10-20
Filing date: 2020-10-20
Publication date: 2021-05-25
Anticipated expiration: 2030-10-20

Abstract

The utility model discloses a quick-repair high-temperature and high-pressure difference valve with a preposed anti-cavitation function; belongs to the technical field of valves; the valve body is provided with a medium inlet and a medium outlet, a valve cavity which is communicated with the medium inlet and the medium outlet and is provided with an opening at one side is arranged in the valve body, a valve rod can be connected in the valve cavity in an up-and-down moving mode along the axial direction, and a valve core is arranged at the lower end of the valve rod; a valve sleeve matched with the valve core is detachably connected in the valve cavity between the medium inlet and the medium outlet along the axial direction, the side wall of the upper part of the valve sleeve is provided with a through hole for conducting the medium outlet, and a pressure reduction structure is formed between the valve sleeve and the lower part of the valve core on the lower side of the through hole; a preposed anti-cavitation device is arranged in the inner hole of the valve sleeve at the lower side of the pressure reducing structure, and the medium passes through the preposed anti-cavitation device, the pressure reducing structure and the through hole in sequence from the medium inlet and then is output from the medium outlet; the utility model aims at providing a easy dismounting, the fast repair high temperature high pressure difference valve that has leading anti cavitation function that can step down and disappear.

Description

Quick-repair high-temperature and high-pressure-difference valve with preposed anti-cavitation function

Technical Field

The utility model relates to a high temperature high pressure differential valve, more specifically say, especially relate to a quick-repair high temperature high pressure differential valve with leading anti cavitation function.

Background

At present, a valve seat is generally machined on a valve body of a steam valve with high temperature and high pressure difference parameters in a thermal power plant, and the hardness is improved by adopting a build-up welding mode; the fluid is shut off by engagement of the valve element and the valve seat. The joint of the valve seat and the valve core is a sealing surface and a throttling surface of the valve in the opening and closing process.

Because the high-temperature and high-pressure difference parameter steam valve has the problems of more switching times, high temperature and pressure of steam-water medium, bad operation condition and the like, the leakage of the sealing surface of the steam-water valve with the high-temperature and high-pressure difference parameter caused by cavitation erosion damage can be easily caused, and the safe and economic operation of equipment is influenced; and the valve is difficult to maintain after being damaged, the workload of replacing the valve is large, and the cost is high.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to the not enough of above-mentioned prior art, provide a simple structure, easy dismounting can the step-down energy dissipation, increase of service life's quick-repair high temperature high pressure difference valve with leading anti cavitation function.

The technical scheme of the utility model is realized like this: a quick-repair high-temperature and high-pressure difference valve with a preposed anti-cavitation function comprises a valve body, wherein a medium inlet and a medium outlet are arranged on the valve body, a valve cavity which is communicated with the medium inlet and the medium outlet and is provided with an opening at one side is arranged in the valve body, a valve rod can be connected in the valve cavity in an up-and-down moving mode along the axial direction, and a valve core is arranged at the lower end of the valve rod; a valve sleeve matched with the valve core is detachably connected in the valve cavity between the medium inlet and the medium outlet along the axial direction, the side wall of the upper part of the valve sleeve is provided with a through hole for conducting the medium outlet, and a pressure reduction structure is formed between the valve sleeve and the lower part of the valve core on the lower side of the through hole; the pressure reducing structure is characterized in that a preposed anti-cavitation device is arranged in an inner hole of the valve sleeve on the lower side of the pressure reducing structure, and a medium enters from the medium inlet and then sequentially passes through the preposed anti-cavitation device, the pressure reducing structure and the through hole and then is output from the medium outlet.

In the quick-repair high-temperature and high-pressure difference valve with the preposed anti-cavitation function, a first sealing structure is arranged between the lower part of the valve sleeve and the valve cavity; a sealing component which is matched with the valve rod and the upper part of the valve sleeve and is used for sealing the valve cavity is arranged at the opening end of the valve cavity; the first sealing structure and the sealing assembly are matched to clamp the fixed valve sleeve.

In the quick-repair high-temperature and high-pressure difference valve with the preposed anti-cavitation function, the first sealing structure comprises a first annular positioning step arranged in a valve cavity on the upper side of the medium inlet, a second annular positioning step matched with the first annular positioning step is arranged at the bottom of the valve sleeve, and a first annular sealing ring is arranged between the first annular positioning step and the second annular positioning step.

In the quick-repair high-temperature high-pressure-difference valve with the preposed anti-cavitation function, the sealing assembly comprises a valve cover which is arranged on the valve body at the open end of the valve cavity and is connected with the valve body through a bolt, and a rod hole matched with the valve rod is arranged in the valve cover; an annular packing groove for sealing a gap between the valve rod and the rod hole is formed in the rod hole at one end, far away from the valve cavity, of the valve cover, sealing packing is arranged in the packing groove, a packing gland is connected to the upper end of the packing groove through a bolt, and a packing gland sleeve is clamped between the packing gland and the packing groove; and a second sealing structure is arranged between the valve cover and the open end of the valve cavity.

In the quick repair high-temperature high-pressure-difference valve with the preposed anti-cavitation function, the second sealing structure comprises an annular sealing groove arranged at the open end of the valve cavity, one end of the valve cover close to the valve cavity is provided with a first sealing ring matched with the sealing groove, and a second annular sealing ring matched with the first sealing ring is arranged in the sealing groove; the valve cover is provided with a pressing ring which is matched with the upper end surface of the valve sleeve and is used for pressing the valve sleeve on the inner side of the first sealing ring.

In the quick-repair high-temperature high-pressure-difference valve with the preposed anti-cavitation function, the preposed anti-cavitation device comprises a hollow cylinder which is connected in a valve sleeve inner hole at the lower side of the pressure reduction structure in an interference manner, a plurality of partition plates are axially arranged in the cylinder inner hole at intervals, and a hedging energy dissipation cavity is formed between two adjacent layers of partition plates; medium energy dissipation inlets and medium energy dissipation outlets are distributed on the side wall of each layer of opposite-flushing energy dissipation cavity at intervals along the circumferential direction in a staggered mode, the medium energy dissipation inlets located on each layer are in one-to-one correspondence with the medium energy dissipation outlets located on the lower layer, energy dissipation grooves for conducting the corresponding medium energy dissipation inlets and the corresponding medium energy dissipation outlets are formed in the outer wall of the cylinder body, and the energy dissipation grooves are matched with the inner wall of the valve sleeve to form a flow guide channel.

In the quick repair high-temperature and high-pressure difference valve with the preposed anti-cavitation function, the second sealing ring is arranged in the valve sleeve inner hole at the lower side of the through hole, and the upper end of the second sealing ring is provided with a first annular sealing inclined plane; a second annular sealing inclined plane matched with the first annular sealing inclined plane is arranged on the valve core; the pressure reducing structure is a pressure reducing block which is integrally formed on the end face of the valve core at the lower side of the second annular sealing inclined plane and is in clearance fit with the inner hole of the second sealing ring; the distance between the second sealing ring and the pressure reduction block is 0.01-0.2 mm.

In the quick-repair high-temperature high-pressure-difference valve with the preposed anti-cavitation function, the outer wall of the pressure reducing block is radially provided with an annular pressure reducing groove.

By adopting the structure, the valve pocket matched with the valve core is detachably connected in the valve pocket between the medium inlet and the medium outlet along the axial direction, so that the valve pocket and valve internals (the valve pocket and the valve rod) on the valve pocket can be conveniently detached and replaced, and the purpose of quick repair is achieved; through being formed with the decompression structure between the valve barrel of through-hole downside and case lower part, can carry out the decompression speed reduction to the medium when the valve is closed, avoid the medium vaporization and then cause the cavitation to sealed face.

Furthermore, the front anti-cavitation device is arranged in front of the pressure reduction structure, and the medium entering the valve sleeve can be subjected to pressure reduction and energy dissipation in advance by changing the flowing direction of the medium and through opposite flushing, so that cavitation is further avoided, and the service life of the valve is prolonged.

Drawings

The present invention will be described in further detail with reference to the following examples, which are not intended to limit the invention.

Fig. 1 is a schematic structural diagram of the present invention;

FIG. 2 is an enlarged view at A in FIG. 1;

FIG. 3 is a schematic structural view of a front anti-cavitation device of the present invention;

FIG. 4 is a schematic view of the internal structure of the front anti-cavitation device of the present invention;

FIG. 5 is a schematic structural view of the valve element of the present invention when fully opened;

fig. 6 is a schematic structural diagram of the middle valve element of the present invention when it is fully closed.

In the figure: 1. a valve body; 1a, a medium inlet; 1b, a medium outlet; 2. a valve cavity; 2a, a first annular positioning step; 2b, a first annular sealing ring; 2c, sealing grooves; 2d, a second annular sealing ring; 3. a valve stem; 3a, a valve core; 3b, a second annular sealing bevel; 3c, reducing the pressure block; 3d, a depressurization tank; 4. a valve housing; 4a, a through hole; 4b, a second annular positioning step; 4c, a second sealing ring; 4d, a first annular sealing bevel; 5. a front anti-cavitation device; 5a, a column body; 5b, a partition board; 5c, oppositely punching the energy dissipation cavity; 5d, a medium energy dissipation inlet; 5e, a medium energy dissipation outlet; 5f, energy dissipation grooves; 6. a seal assembly; 6a, a valve cover; 6b, a rod hole; 6c, a packing groove; 6d, sealing and filling; 6e, a packing gland; 6f, packing and pressing the sleeve; 6g, a first sealing ring; 6h, pressing the ring; 7. a support; 8. a bearing chamber.

Detailed Description

Referring to fig. 1 to 6, the quick-repair high-temperature and high-pressure difference valve with a front anti-cavitation function of the present invention includes a valve body 1, a medium inlet 1a and a medium outlet 1b are arranged on the valve body 1, a valve cavity 2 with a single side open and communicating the medium inlet 1a and the medium outlet 1b is arranged in the valve body 1, a valve rod 3 can be connected to the valve cavity 2 along the axial direction in a vertical movement manner, and a valve core 3a is arranged at the lower end of the valve rod 3; a valve sleeve 4 matched with the valve core 3a is detachably connected in the valve cavity 2 between the medium inlet 1a and the medium outlet 1b along the axial direction, the side wall of the upper part of the valve sleeve 4 is provided with a through hole 4a communicated with the medium outlet 1b, and a pressure reduction structure is formed between the valve sleeve 4 and the lower part of the valve core 3a at the lower side of the through hole 4 a.

A second sealing ring 4c is arranged in the inner hole of the valve sleeve 4 at the lower side of the through hole 4a, and a first annular sealing inclined surface 4d is formed at the upper end of the second sealing ring 4 c; a second annular sealing bevel 3b is provided on the valve core 3a to mate with the first annular sealing bevel 4 d. The pressure reducing structure is a pressure reducing block 3c which is integrally formed on the end surface of the valve core 3a at the lower side of the second annular sealing inclined surface 3b and is in clearance fit with the inner hole of the second sealing ring 4 c; the distance between the second sealing ring 4c and the pressure reduction block 3c is 0.01-0.2 mm; the valve core 3a can be opened and closed in the valve sleeve 4 through the mutual matching of the first annular sealing inclined surface 4d at the upper end of the second sealing ring 4c and the second annular sealing inclined surface 3b arranged on the valve core 3a, so that the flow of a medium in the valve sleeve 4 is controlled; the pressure reducing block 3c which is in clearance fit with the inner hole of the second sealing ring 4c is arranged on the end surface of the valve core 3a, so that the medium can be reduced in pressure when the valve core 3a is opened in the valve sleeve 4, and the flow rate of the medium is reduced.

Preferably, the outer wall of the pressure reducing block 3c is provided with an annular pressure reducing groove 3d along the radial direction; through radially setting up annular pressure-reducing groove 3d at decompression piece 3c outer wall, pressure-reducing groove 3d can make the medium form the vortex when passing through the decompression piece to further reduce medium velocity of flow and pressure, prevent that the medium from scouring the sealed face between decompression piece 3c and second sealing ring 4c, prolong sealed life.

Furthermore, a preposed anti-cavitation device 5 is arranged in an inner hole of the valve sleeve 4 at the lower side of the pressure reduction structure, and the medium enters from the medium inlet 1a and then sequentially passes through the preposed anti-cavitation device 5, the pressure reduction structure and the through hole 4a and then is output from the medium outlet 1 b; the valve sleeve 4 matched with the valve core 3a is detachably connected in the valve cavity 2 between the medium inlet 1a and the medium outlet 1b along the axial direction, so that the valve sleeve 4 and valve internals (the valve sleeve 4 and the valve rod 3) on the valve sleeve 4 can be conveniently detached and replaced, and the purpose of quick repair is achieved.

Through being formed with the pressure reduction structure between valve barrel 4 and the case 3a lower part of through-hole 4a downside, can reduce the pressure to the medium that flows through valve barrel 4 when the valve switch, reduce the velocity of flow of medium and in order to slow down the scouring force of medium, prolong the life of case 3a and valve barrel 4. Through being provided with leading anti cavitation erosion device 5 in valve barrel 4 hole of step-down structure downside, can carry out the step-down energy dissipation to the medium that gets into valve barrel 4, prevent that valve barrel 4 from taking place the cavitation, protect through-flow part in the valve body 1 not receive the cavitation damage, prolong the life of valve.

Preferably, a first sealing structure is arranged between the lower part of the valve sleeve 4 and the valve cavity 2; a sealing component 6 which is matched with the upper parts of the valve rod 3 and the valve sleeve 4 and is used for sealing the valve cavity 2 is arranged at the opening end of the valve cavity 2; the first sealing structure is matched with the sealing component 6 to clamp and fix the valve sleeve 4; by arranging the first sealing structure, the valve pocket 4 and the valve cavity 2 at the end of the medium inlet 1a can be effectively sealed, and the sealing performance of the valve is improved; by arranging the sealing assembly 6, the open end of the valve cavity 2 can be effectively sealed, and leakage is prevented; through setting up the first seal structure in valve barrel 4 lower part and setting up at the seal assembly 6 on valve barrel 4 upper portion mutually support, can realize fixing the centre gripping of valve barrel 4 in valve chamber 2 to can carry out the dismouting as required.

In the embodiment, the first sealing structure comprises a first annular positioning step 2a arranged in the valve cavity 2 on the upper side of the medium inlet 1a, a second annular positioning step 4b matched with the first annular positioning step 2a is arranged at the bottom of the valve sleeve 4, and a first annular sealing ring 2b is arranged between the first annular positioning step 2a and the second annular positioning step 4 b; through setting up the first annular location step 2a in the side valve chamber 2 on medium inlet 1a and setting up the second annular location step 4b in the valve pocket 4 bottom mutually support, can effectively fix a position valve pocket 4 in the valve chamber 2 to can guarantee the sealed effect between valve pocket 4 and the valve chamber 2 through setting up the first ring type seal circle 2b between first annular location step 2a and second ring type location step 4 b. Of course, it is also possible to form only a positioning step in the valve body and to mate the lower end of the valve sleeve directly with the positioning step, and such equivalent alternatives will be readily apparent to those skilled in the art on the basis of the above disclosure.

In this embodiment, the sealing assembly 6 comprises a valve cover 6a which is arranged on the valve body 1 at the open end of the valve cavity 2 and is connected with the valve body 1 through a bolt, and a rod hole 6b matched with the valve rod 3 is arranged in the valve cover 6 a; an annular packing groove 6c used for sealing a gap between the valve rod 3 and the rod hole 6b is formed in the rod hole 6b of the valve cover 6a at one end far away from the valve cavity 2, a sealing packing 6d is arranged in the packing groove 6c, a packing gland 6e is connected to the upper end of the packing groove 6c through a bolt, and a packing gland sleeve 6f is clamped between the packing gland 6e and the packing groove 6 c; a second sealing structure is arranged between the valve cover 6a and the open end of the valve cavity 2; a valve cover 6a is connected to the valve body 1 at the open end of the valve cavity 2 through bolts, and the valve cover 6a and the valve cavity 2 are sealed through a second sealing structure; the packing gland 6e which is connected to one end, far away from the valve cavity 2, of the valve cover 6a through a bolt is matched with the packing gland 6f, and the sealing packing 6d is pressed in the sealing groove 2c, so that the sealing between the rod hole 6b and the valve rod 3 is realized.

Preferably, a bracket 7 is provided on the bonnet 6a outside the packing gland 6e, and a bearing chamber 8 fitted to the top of the valve stem 3 is provided on the top of the bracket 7. The bearing in the bearing chamber can enable the valve rod to rotate more stably, so that the valve rod is prevented from swinging, and the use precision of the valve is improved.

Preferably, the second sealing structure comprises an annular sealing groove 2c arranged at the open end of the valve cavity 2, the valve cover 7 is provided with a first sealing ring 6g matched with the sealing groove 2c at one end close to the valve cavity 2, and a second annular sealing ring 2d matched with the first sealing ring 6g is arranged in the sealing groove 2 c; the valve cover 6a is provided with a pressing ring 6h which is matched with the upper end surface of the valve sleeve 4 and is used for pressing the valve sleeve 4 on the inner side of the first sealing ring 6 g; the valve cover 6a and the valve cavity 2 can be sealed by a sealing groove 2c arranged at the open end of the valve cavity 2 and a first sealing ring 6g on the valve cover 6a which are matched with each other and a second annular sealing ring 2d arranged in the sealing groove 2 c; meanwhile, the compressing ring 6h arranged on the valve cover 6a is matched with the upper end face of the valve sleeve 4, so that the valve sleeve 4 can be fixed, the bottom of the valve sleeve 4 is extruded by the first annular sealing ring 2b by compressing the valve sleeve 4, the valve sleeve 4 is tightly matched with the valve cavity 2, and the sealing effect is enhanced.

In this embodiment, the preposed anti-cavitation device 5 includes a hollow cylinder 5a which is connected in the inner hole of the valve sleeve 4 at the lower side of the pressure reduction structure in an interference manner, a plurality of partition plates 5b are axially arranged in the inner hole of the cylinder 5a at intervals, and an opposite-flushing energy dissipation cavity 5c is formed between two adjacent layers of partition plates 5 b; medium energy dissipation inlets 5d and medium energy dissipation outlets 5e are circumferentially spaced and staggered on the side wall of each layer of opposite energy dissipation cavity 5c, the medium energy dissipation inlets 5d positioned on each layer correspond to the medium energy dissipation outlets 5e on the lower layer one by one, energy dissipation grooves 5f for communicating the corresponding medium energy dissipation inlets 5d and medium energy dissipation outlets 5e are arranged on the outer wall of the cylinder 5a, and the energy dissipation grooves 5f are matched with the inner wall of the valve sleeve 4 to form a flow guide channel; a hollow column body 5a is arranged, a plurality of layers of partition plates 5b are arranged in the column body 5a, and the adjacent two layers of partition plates 5b are communicated with each other through a medium energy dissipation inlet 5d and a medium energy dissipation outlet 5e to form an opposite energy dissipation cavity 5 c. By adopting the structure, the medium entering the medium inlet 1a can be reversed for a plurality of times in the column body 5a and continuously reduced in pressure and energy dissipation, so that the cavitation phenomenon can be effectively prevented, and the phenomenon that the normal work of the valve is influenced by the damage of the through-flow part in the valve body 1 is avoided.

As for the number of the partition plates 5b in the front anti-cavitation device 5, it can be set according to specific requirements. Theoretically, the higher the medium pressure, the greater the number of the partitions 5 b. As will also be readily apparent to those skilled in the art.

The utility model discloses the theory of operation: when the valve is opened, the valve rod 3 controls the valve core 3a to move upwards, so that the second annular sealing inclined surface 3b on the valve core 3a is separated from the first annular sealing inclined surface 4d in the valve sleeve 4; high-temperature and high-pressure media enter a valve cavity 2 of a valve body 1 from a medium inlet 1a, firstly go through a preposed anti-cavitation device 5 arranged at the bottom of a valve sleeve 4 to perform pressure reduction and energy dissipation, the media after pressure reduction and energy dissipation continuously flow through a pressure reduction structure on a valve core 3a, and further pressure reduction and energy dissipation are performed through the pressure reduction structure, so that the pressure reduction and energy dissipation effect is determined, the cavitation phenomenon is avoided to the maximum extent, and the media after pressure reduction and energy dissipation sequentially pass through holes 4a arranged on the side walls of the upper parts of the valve core and the valve sleeve 4 and are finally output through a medium outlet.

When the valve is closed, the valve rod 3 controls the valve core 3a to move downwards, so that the second annular sealing inclined surface 3b on the valve core 3a and the first annular sealing inclined surface 4d in the valve sleeve 4 are slowly closed, and in the process, the preposed anti-cavitation device and the pressure reduction structure have the same functions of reducing pressure and energy and avoiding cavitation.

The above embodiment is the preferred embodiment of the present invention, which is only used to facilitate the explanation of the present invention, it is not right to the present invention, which makes the restriction on any form, and any person who knows commonly in the technical field can use the present invention to make the equivalent embodiment of local change or modification without departing from the technical features of the present invention.

Claims

1. A quick-repair high-temperature and high-pressure difference valve with a preposed anti-cavitation function comprises a valve body (1), wherein a medium inlet (1a) and a medium outlet (1b) are arranged on the valve body (1), and is characterized in that a valve cavity (2) which is communicated with the medium inlet (1a) and the medium outlet (1b) and is provided with an opening on one side is arranged in the valve body (1), a valve rod (3) can be connected in the valve cavity (2) in an up-and-down moving mode along the axial direction, and a valve core (3a) is arranged at the lower end of the valve rod (3);

a valve sleeve (4) matched with the valve core (3a) is detachably connected in the valve cavity (2) between the medium inlet (1a) and the medium outlet (1b) along the axial direction, the side wall of the upper part of the valve sleeve (4) is provided with a through hole (4a) for conducting the medium outlet (1b), and a pressure reduction structure is formed between the valve sleeve (4) at the lower side of the through hole (4a) and the lower part of the valve core (3 a); a preposed anti-cavitation device (5) is arranged in an inner hole of the valve sleeve (4) on the lower side of the pressure reducing structure, and a medium enters from the medium inlet (1a) and then sequentially passes through the preposed anti-cavitation device (5), the pressure reducing structure and the through hole (4a) and then is output from the medium outlet (1 b).

2. The quick-repair high-temperature high-pressure-difference valve with the preposed anti-cavitation function is characterized in that a first sealing structure is arranged between the lower part of the valve sleeve (4) and the valve cavity (2); a sealing component (6) which is matched with the upper parts of the valve rod (3) and the valve sleeve (4) and is used for sealing the valve cavity (2) is arranged at the opening end of the valve cavity (2); the first sealing structure and the sealing component (6) are matched to clamp and fix the valve sleeve (4).

3. The quick-repair high-temperature high-pressure-difference valve with the preposed anti-cavitation function is characterized in that the first sealing structure comprises a first annular positioning step (2a) arranged in the valve cavity (2) on the upper side of the medium inlet (1a), a second annular positioning step (4b) matched with the first annular positioning step (2a) is arranged at the bottom of the valve sleeve (4), and a first annular sealing ring (2b) is arranged between the first annular positioning step (2a) and the second annular positioning step (4 b).

4. The quick-repair high-temperature high-pressure difference valve with the preposed anti-cavitation function is characterized in that the sealing assembly (6) comprises a valve cover (6a) which is arranged on the valve body (1) at the open end of the valve cavity (2) and is connected with the valve body (1) through a bolt, and a rod hole (6b) matched with the valve rod (3) is arranged in the valve cover (6 a);

an annular packing groove (6c) used for sealing a gap between the valve rod (3) and the rod hole (6b) is formed in the rod hole (6b) of the valve cover (6a) at one end far away from the valve cavity (2), a sealing packing (6d) is arranged in the packing groove (6c), a packing gland (6e) is connected to the upper end of the packing groove (6c) through a bolt, and a packing gland sleeve (6f) is clamped between the packing gland (6e) and the packing groove (6 c); a second sealing structure is arranged between the valve cover (6a) and the open end of the valve cavity (2).

5. The quick-repair high-temperature high-pressure-difference valve with the preposed anti-cavitation function is characterized in that the second sealing structure comprises an annular sealing groove (2c) arranged at the open end of the valve cavity (2), the valve cover (6a) is provided with a first sealing ring (6g) matched with the sealing groove (2c) at one end close to the valve cavity (2), and a second annular sealing ring (2d) matched with the first sealing ring (6g) is arranged in the sealing groove (2 c); the valve cover (6a) is provided with a pressing ring (6h) which is matched with the upper end surface of the valve sleeve (4) and is used for pressing the valve sleeve (4) on the inner side of the first sealing ring (6 g).

6. The quick-repair high-temperature high-pressure-difference valve with the preposed anti-cavitation function is characterized in that the preposed anti-cavitation device (5) comprises a hollow cylinder (5a) which is connected in an inner hole of a valve sleeve (4) at the lower side of a pressure reduction structure in an interference manner, a plurality of partition plates (5b) are axially arranged in the inner hole of the cylinder (5a) at intervals, and opposite-flushing energy dissipation cavities (5c) are formed between two adjacent layers of partition plates (5 b);

medium energy dissipation inlets (5d) and medium energy dissipation outlets (5e) are circumferentially and alternately distributed on the side wall of each layer of opposite energy dissipation cavity (5c), the medium energy dissipation inlets (5d) positioned on each layer correspond to the medium energy dissipation outlets (5e) on the lower layer one by one, energy dissipation grooves (5f) for communicating the corresponding medium energy dissipation inlets (5d) and the corresponding medium energy dissipation outlets (5e) are arranged on the outer wall of the column body (5a), and the energy dissipation grooves (5f) are matched with the inner wall of the valve sleeve (4) to form a flow guide channel.

7. The quick-repair high-temperature high-pressure difference valve with the preposed anti-cavitation function is characterized in that a second sealing ring (4c) is arranged in the inner hole of the valve sleeve (4) at the lower side of the through hole (4a), and a first annular sealing inclined surface (4d) is formed at the upper end of the second sealing ring (4 c); a second annular sealing inclined surface (3b) matched with the first annular sealing inclined surface (4d) is arranged on the valve core (3 a);

the pressure reducing structure is a pressure reducing block (3c) which is integrally formed on the end surface of the valve core (3a) at the lower side of the second annular sealing inclined plane (3b) and is in clearance fit with the inner hole of the second sealing ring (4 c); the distance between the second sealing ring (4c) and the pressure reducing block (3c) is 0.01-0.2 mm.

8. The quick-repair high-temperature high-pressure difference valve with the preposed anti-cavitation function is characterized in that the outer wall of the pressure reducing block (3c) is provided with an annular pressure reducing groove (3d) along the radial direction.