CN217328486U

CN217328486U - Drainage cavitation-resistant scouring-resistant stop valve for power station

Info

Publication number: CN217328486U
Application number: CN202221263550.9U
Authority: CN
Inventors: 张在江; 李明明; 陈首岐; 于艳敏
Original assignee: HARBIN SONGLIN POWER STATION EQUIPMENT CO Ltd
Current assignee: HARBIN SONGLIN POWER STATION EQUIPMENT CO Ltd
Priority date: 2022-05-25
Filing date: 2022-05-25
Publication date: 2022-08-30
Anticipated expiration: 2032-05-25

Abstract

The utility model relates to a hydrophobic anti cavitation erosion of power station scour protection stop valve, which comprises a valve body, be equipped with vertical valve pocket in the valve pocket, be equipped with disk seat and upper seal disk seat in the valve pocket, the disk seat is located between lumen and the cavity of resorption, the upper seal disk seat is located between epicoele and the lumen, the case is located the lumen, with lumen sliding fit, the valve rod passes the epicoele, its lower extreme connection case, the upper end is located outside the valve body, be located and be equipped with radial outside convex annular flange on the valve rod of lumen, annular flange is located the top of case, the sealed face of disk seat up, the sealed face of upper seal disk seat is down, constitute valve seal and top seal with the lower seal face of case and the last sealed face of annular flange respectively, the medium passage intercommunication middle chamber of advancing of valve, go out medium passage intercommunication cavity of resorption, disk seat and valve body adopt the components of a whole that can function independently structure, can set up the throttle cover in the reducing through-hole of valve body. The utility model has the characteristics of sealed reliable, wear-resisting, anti erosion, simple structure, simple to operate, long service life, maintenance convenience etc.

Description

Drainage anti-cavitation erosion-proof stop valve for power station

Technical Field

The utility model relates to an anti cavitation erosion prevention stop valve especially relates to a power station subcritical unit, the hydrophobic anti cavitation erosion prevention stop valve of power station, the high-efficient supercritical power station of supercritical unit, can be applied to water and steam occasions such as the turbine main steam conduit of electric power enterprise is hydrophobic, the steam extraction, the feedwater heater is shut off, boiler trap, economizer trap, the recirculated bypass isolation valve of boiler feedwater, boiler feedwater shutoff valve, the steam pocket valve that drains, the periodic blowoff valve of boiler.

Background

From the 80 s of the 20 th century, the domestic main power station main engine and auxiliary engine manufacturing industry successively introduced foreign advanced design technology and manufacturing technology to meet the needs of domestic large-scale power station unit development. Up to now, the main and auxiliary equipments of the subcritical supercritical power plant unit of large power station have been substantially localized, including the important main and auxiliary equipments of 660MW and 1000MW high-efficiency supercritical power plant unit.

In recent years, large-scale power stations develop rapidly, the valve manufacturing industry in China does not follow the development rhythm of power station installation, and most of domestic high-end valves still depend on import. China still has the defects of relatively laggard technology, unstable reliability, complex manufacturing process, difficulty in maintenance and the like of high-end valves, and needs to invest relatively large manpower and maintenance time.

At present, be equipped with in the valve body of domestic pneumatic stop valve disk seat structure and with the case, disk seat and case constitute valve seal pair, and the case is connected with the valve rod, and pneumatic means can drive the valve rod and reciprocate, and then drives the valve and open or turn-off, when being used for high pressure high temperature occasion, often shows that precision and quality grade are not high, wherein mainly there are following some structural reasons: the sealing surface adopts surface contact, and the sealing is not tight when the sealing device is used in a high-pressure occasion; the valve core adopts a hook type, and the valve core and the valve rod are positioned at different positions; the sealing surface is easy to erode, and the guide part of the valve core is easy to wear; in addition, if the sealing surface is directly welded in the valve body to form the valve seat, when the sealing surface of the valve seat has problems, the valve body needs to be integrally replaced, and the maintenance cost is high.

SUMMERY OF THE UTILITY MODEL

For overcoming the above-mentioned defect of prior art, the utility model provides a hydrophobic anti cavitation erosion prevention of power station scour prevention stop valve, this valve have sealed reliable, wear-resisting, anti erosion, simple structure, simple to operate, long service life, the on-the-spot maintenance of being convenient for and maintenance cost low grade characteristics.

The utility model adopts the technical proposal that:

a hydrophobic anti-cavitation erosion and anti-scouring stop valve for a power station comprises a valve body, wherein a vertical valve cavity is arranged in the valve body, a valve seat (or called valve seat or main valve seat) and an upper sealing valve seat are arranged in the valve cavity, the valve seat and the upper sealing valve seat divide the valve cavity into an upper cavity, a middle cavity and a lower cavity, the valve seat is positioned between the middle cavity and the lower cavity (a dividing part of the middle cavity and the lower cavity), the upper sealing valve seat is positioned between the upper cavity and the middle cavity (a dividing part of the upper cavity and the middle cavity), a valve core is positioned in the middle cavity and is matched with the middle cavity in a sliding (axial sliding) manner, a valve rod penetrates through the upper cavity, the lower end of the valve core is connected with the upper end of the valve core, the upper end of the valve rod is positioned outside the valve body and is connected with a driving device, an annular flange which protrudes outwards in the radial direction is arranged on the valve rod in the middle cavity, the annular flange is positioned above the valve core, and the sealing surface of the valve seat faces upwards, the sealing surface of the upper sealing valve seat faces downwards, a valve seal and an upper seal are formed by the upper sealing surface of the upper sealing valve seat and the lower sealing surface of the valve core and the upper sealing surface of the annular flange respectively, a medium inlet channel of the valve (or the valve body) is communicated with the middle cavity, a medium outlet channel of the valve is communicated with the lower cavity, the valve seat and the valve body are of a split structure, so that the valve seat can be detached relative to the valve seat, a valve seat assembling spigot is arranged on the valve body between the middle cavity and the lower cavity, and the valve seat is installed on the valve seat assembling spigot. When the valve core moves downwards to seal the lower sealing surface of the valve core with the sealing surface of the valve seat, the medium channel from the middle cavity to the lower cavity is cut off, the valve is closed, when the valve core moves upwards to seal the lower sealing surface of the valve core away from the sealing surface of the valve seat and the upper sealing surface of the annular flange with the sealing surface of the upper sealing valve seat, the valve is in a full-open state, the medium channel from the middle cavity to the upper cavity is cut off, and the medium cannot flow into the upper cavity.

The sealing between the valve rod and the valve body can be realized by adopting the prior art, the packing for sealing the valve rod is filled between the valve rod and the inner wall of the upper cavity or the inner wall of the middle hole of the valve cover, and the packing gland can be arranged above the packing to prevent the medium flowing into the middle cavity from leaking from the gap between the valve rod and the valve body or the valve cover.

The bottom of the lower cavity is closed, and the medium flowing into the lower cavity can only flow out of the medium outlet channel of the valve.

The upper sealing valve seat and the sealing arrangement of the annular flange and upper sealing valve seat may be any suitable existing valve sealing technique.

Other configurations of the valve may be any suitable known technique.

A hydrophobic anti-cavitation erosion anti-scouring stop valve for a power station comprises a valve body, wherein the valve body is provided with a vertical reducing round hole (a hole with a circular cross section), the reducing round hole is a blind hole with an open upper end, the aperture of the upper section of the reducing round hole is larger than that of the lower section of the reducing round hole, a valve seat assembly spigot is arranged at a reducing part between the upper section and the lower section of the reducing round hole, a valve seat (or called valve seat or main valve seat) is arranged on the valve seat assembly spigot (the valve seat is detachable relative to the valve body), or the reducing part between the upper section and the lower section of the reducing round hole is formed by the valve seat, a tubular throttling sleeve (or called anti-scouring throttling sleeve or anti-scouring throttling sleeve) is arranged in the reducing round hole, the throttling sleeve is positioned in the upper section of the reducing round hole, the bottom surface of the throttling sleeve is abutted against the valve seat, the outer side surface of the throttling sleeve is matched with the inner wall of the upper section of the reducing round hole so as to realize the fixation of the throttling sleeve in each plane direction, the inner diameter of the reducing circular hole is larger than the diameter of the lower section of the reducing circular hole, so that the inner edge part of the valve seat is exposed from the inner side (radial inner side) of the inner wall of the throttling sleeve so as to be matched with a corresponding sealing surface at the bottom of the valve core to form valve seat sealing, an expansion section (or called expanding section or expansion section) is further arranged in the reducing circular hole, the expansion section is axially positioned between the upper end of the throttling sleeve and the bottom end of the valve seat (the upper end is lower than the upper end of the throttling sleeve, the lower end is higher than the bottom end of the valve seat), the diameter of the expansion section is larger than the outer diameter of the throttling sleeve, so that an annular gap allowing a medium to flow through is reserved between the inner wall of the expansion section and the throttling sleeve (the outer side surface of the throttling sleeve), a radial throttling hole (or called throttling through hole) communicated with the annular gap is arranged on the side wall of the throttling sleeve, and the inner end of a medium inlet channel of the valve body is communicated with the annular gap (or arranged on the outer wall of the annular gap), the inner end of the medium outlet channel of the valve body is communicated with the lower part of the lower section of the reducing circular hole (or the lower hole wall of the lower section of the reducing circular hole), a valve core (or called valve clack) is arranged in the throttling sleeve, the valve core is in a shape of a rotary body and is in a waist shape, the valve core is provided with a top surface and a bottom surface, the upper part and the lower part of the side surface of the valve core are respectively provided with an upper flange which is radially outwards convex and a lower flange which is radially outwards convex, so that the valve core is in a waist shape, the outer side surface of the upper flange and the outer side surface of the lower flange are both preferably cylindrical surfaces, the main part of the outer side surface of the valve core (namely the middle part of the valve core) between the upper flange and the lower flange is preferably cylindrical, the outer side surfaces of the upper flange and the outer side surface of the lower flange are cylindrical surfaces, the diameters of the upper flange and the outer side surfaces of the lower flange are equal, and are in sliding fit with the inner wall of the throttling sleeve (a fit mode allowing relative sliding, or called axial guide fit, and may generally be provided with a small fit clearance), an inner flange protruding radially inward is provided at a top opening of the throttle sleeve, the valve rod passes through the top opening of the throttle sleeve, the lower end of the valve rod is connected to the valve element, the upper end of the valve rod is located outside the valve body, an annular flange protruding radially outward is provided on the valve rod located in the throttle sleeve, the annular flange is located above the valve element, mutually-fitted sealing surfaces are provided at the top of the valve seat and the bottom of the valve element, respectively, for forming a valve seal, mutually-fitted sealing surfaces are provided at the bottom of the inner flange and the top of the annular flange, respectively, for forming an upper seal, a valve cover is fixedly mounted on the top opening of the valve body (e.g., connected by bolts), and a central hole through which the valve rod can pass is provided on the valve cover.

Preferably, the valve core is provided with a valve rod blind hole with an open upper end, the lower end of the valve rod extends into the valve rod blind hole, an annular pin (or called a circular pin, the shape of which is annular in a use state) for connecting the valve rod in the valve rod blind hole and the inner wall of the blind hole is arranged between the valve rod in the valve rod blind hole and the inner wall of the blind hole, and annular grooves corresponding to each other are respectively arranged on the outer side surface of the valve rod in the valve rod blind hole and the inner wall of the blind hole and used for embedding the annular pin.

Preferably, the lower end surface of the valve stem is a convex surface of revolution, for example, a spherical crown surface.

The bottom surface of the valve rod blind hole can be a horizontal plane.

Preferably, the outer side surface of the throttling sleeve is a reducing cylindrical surface, the outer diameter of the upper section of the throttling sleeve is smaller than that of the lower section of the throttling sleeve, the reducing part between the upper section of the throttling sleeve and the lower section of the throttling sleeve is positioned above the expansion section, an annular gap is formed between the upper section of the throttling sleeve and the reducing circular hole, a sealing ring is installed in the annular gap, an annular cylindrical protrusion which extends downwards and extends into the annular gap is arranged at the bottom end of the valve cover, and the annular cylindrical protrusion is tightly pressed on the sealing ring.

Preferably, the reducing part of the reducing cylindrical surface is a tapered surface with a small upper part and a large lower part, namely, the bottom wall of the annular gap is a tapered surface with a small upper part and a large lower part, when the valve cover and the valve body are assembled, the annular cylindrical protrusion is pressed on the sealing ring, the bottom surface of the sealing ring is pressed on the tapered surface, and a pressure self-sealing structure is formed.

Preferably, the top of the valve body and the bottom of the valve cover are respectively provided with assembling stop openings which are matched with each other, and a sealing gasket is arranged between the assembling stop openings which are matched with each other.

Preferably, a packing chamber is arranged between the inner wall of the top of the middle hole of the valve cover and the valve rod, packing for sealing or a sealing element is filled in the packing chamber, a packing gland is arranged at the top of the valve cover, the packing gland is in a shape of a rotary body, an annular packing gland flange which is radially outward convex is arranged at the upper part of the outer side surface of the packing gland, the top surface of the annular packing gland flange is in an umbrella shape, a pressing plate is arranged above the packing gland, a conical concave surface corresponding to the top surface of the annular packing gland flange is arranged at the bottom of the pressing plate and is pressed on the top surface of the annular packing gland flange, and the pressing plate is fixedly connected with the valve cover. The degree of compression of the packing gland against the sealing material can be adjusted to achieve an effective seal and allow the valve stem to rotate.

The pressure plate is provided with a middle hole for penetrating the valve rod, and the diameter of the middle hole of the pressure plate can be equal to or larger than that of the middle hole of the packing gland.

Preferably, the bottom surface of the packing gland is a plane, is positioned in the packing chamber and is in close contact with the top of the packing to moderately compress the packing.

The packing gland and the packing pressure plate are of a split structure and are matched by the cambered surfaces, so that the gland can be automatically aligned conveniently, the packing is uniformly compressed when the packing is tightly packed, and the valve rod centering is facilitated.

Preferably, the sealing surface of the top of the valve seat and the sealing surface of the bottom of the valve element are both conical (frustum-shaped).

Preferably, an inner edge (radially inner edge) of the sealing surface of the bottom portion of the valve element is located radially inside an inner edge of the sealing surface of the top portion of the valve seat, an outer edge (radially outer edge) is located radially outside an outer edge of the sealing surface of the top portion of the valve seat, and a taper angle of the sealing surface of the bottom portion of the valve element is different from a taper angle of the sealing surface of the top portion of the valve seat.

Preferably, the sealing surface of the bottom of the inner flange may be a tapered surface with a small top and a large bottom, the outer edge (radially outer edge) of the sealing surface is connected with the horizontal bottom surface of the inner flange, the inner edge (radially inner edge) of the sealing surface is connected with the cylindrical inner side surface of the throttle sleeve, and the sealing surface of the top of the annular flange may be a tapered surface with a small top and a large bottom.

The inner hole of the throttling sleeve is connected with a shaft shoulder (radial flange) of the valve core in a guiding mode, the top of the inner hole is of a necking down (inner flange) structure, and a small inner hole connected with the valve rod in a guiding mode is formed.

And a gap allowing relative deflection for a certain small angle is reserved between the throttling sleeve and the valve core (the upper radial flange and the lower radial flange of the valve core) and the valve rod.

The packing gland is matched with the packing chamber of the valve cover and is used for compressing packing of the packing chamber; and an inner hole of the packing gland is matched with the valve rod in a guiding way.

The utility model has the advantages that:

1) because the valve seat and the valve body adopt a split structure, the valve seat can be detached relative to the valve body, the valve seat is convenient to maintain, the sealing problem of the valve seat can be solved only by replacing the valve seat during valve maintenance, the valve body is not required to be replaced, the maintenance cost can be effectively saved, and the loss is reduced.

2) Because a double-sealing structure is adopted between the valve body and the valve cover, the first heavy-sealing structure is a pressure self-sealing structure formed by a sealing ring in an annular gap between the throttling sleeve and the reducing circular hole of the valve body, the second heavy-sealing structure is a forced sealing structure formed by a sealing gasket between the valve body and the assembling seam allowance which are matched with each other, the double sealing between the valve body and the valve cover is realized, the safety service performance of the valve is ensured, when a medium flows into the valve body, the medium enters the annular gap between the upper section of the throttling sleeve and the valve body through the gap between the valve body and the throttling sleeve, the sealing ring is compressed, the inner wall of the sealing ring is in close contact with the throttling sleeve, the outer wall of the sealing ring is in close contact with the valve body, thereby the pressure self-sealing function is realized, the sealing gasket is deformed and is tightly attached to the joint surface of the valve body and the valve cover by screwing a connecting bolt between the valve cover and the valve body, and the forced sealing function is realized.

3) Because the reverse sealing (upper sealing) structure relative to the valve seal is arranged, the sealing function is realized at the full-open position of the valve, the pressure at the packing position of the valve is reduced, and the service life of the packing is prolonged.

4) The sealing pair adopts linear sealing, the sealing specific pressure is high, the sealing is reliable, and the sealing surface adopts cobalt-based hard alloy surfacing, so that the sealing pair is wear-resistant and erosion-resistant.

5) Due to the adoption of the integral die forging of the valve body, the valve body has good flow linearity, saves materials, is friendly in flexibility, and can be forged into valve bodies with different pressure levels according to requirements, so that the production period is shortened, the valve body and the valve cover adopt split structures, a valve seat is formed without surfacing a sealing surface in the valve body, the inner cavity of the valve body is short, the inner diameter of the valve body is increased, the selection of a mechanical tool is facilitated, the machining difficulty of the valve body is reduced, the problem that deep holes are difficult to surfacing is solved, and the labor production efficiency is effectively improved.

6) Due to the adoption of an anti-impact throttling sleeve structure, the matched guiding of a valve core shaft shoulder and an inner hole of a throttling sleeve and the guiding of a valve rod and the upper part of the throttling sleeve are effectively ensured; the valve core and the throttling sleeve are effectively ensured to be aligned, and the valve rod and the throttling sleeve are aligned; the valve core and the valve rod are in mortise and tenon joint, enough clearance is reserved, the valve core and the valve rod are in floating connection through an annular pin, the valve core can have a certain swinging amount relative to the valve rod, and the valve core and the sealing surface of the valve seat are in contact with enough adjustment amount, so that the valve core can be automatically centered and aligned; the sealing surfaces of the valve core and the valve seat are all contained in the throttling sleeve, so that the scouring of media to the sealing surfaces is effectively reduced, and the service lives of the valve core and the valve seat are prolonged.

7) Because the packing gland is matched with the pressure plate by the cambered surface, the gland can be automatically aligned conveniently, so that the packing can be uniformly compressed when the packing is tightly packed, and the valve rod centering is facilitated.

Drawings

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

FIG. 2 is an enlarged view of the double seal between the valve seat and the valve cover of FIG. 1 and the upper seal of the valve;

FIG. 3 is an enlarged view of the valve cartridge, valve seat, and throttle sleeve of FIG. 1;

FIG. 4 is a cross-sectional view of the annular pin connection of FIG. 3;

FIG. 5 is an enlarged view of the valve cartridge of FIG. 1 when open;

FIG. 6 is an enlarged view of the valve cartridge of FIG. 1 during opening;

FIG. 7 is a schematic illustration of the valve stem of FIG. 1;

FIG. 8 is a schematic structural view of the valve cartridge of FIG. 1;

FIG. 9 is a schematic view of the construction of the throttle sleeve of FIG. 1;

FIG. 10 is a schematic view of the valve seat of FIG. 1;

fig. 11 is a schematic structural view of the valve body of fig. 1.

Detailed Description

Referring to fig. 1-11, the utility model provides a power station drainage anti-cavitation erosion anti-scouring stop valve, which can be widely applied to large-scale subcritical, supercritical and high-efficiency supercritical power station units and used in various drainage places. Valve gap 4 including valve body 12, the die forging of die forging (solid forging), set up in disk seat 16, throttle sleeve (scour prevention throttle sleeve) 9 in the valve body, with the disk seat constitutes sealed vice case 17 and drives valve core straight line lift's valve rod 19, the case is solid of revolution structure, on the case with disk seat complex down sealed face 33 and case guide site (the upper portion of side and the radial evagination's of lower part upper flange and lower flange) 30, 31 equal surfacing department tai li alloy, the case adopts annular pin 18 to link with the valve rod, the head (lower terminal surface) 34 of valve rod is arc shape (bellied rotating surface), can look for the center automatically after assembling with the case, effectively prevents fluid medium's erodeing under the protection of scour prevention throttle sleeve.

The valve body is formed by integral die forging, so that the material is saved, the leakage points are few, the strength can be flexibly selected according to the pressure (the strength is high, the flexibility is strong), the quality is good, and the valve body is mainly characterized in that: the die forging valve body has the advantages of uniform wall thickness, high surface quality, small machining allowance and light weight, and the hardness, chemical components, mechanical properties and the like can well ensure various properties required by the valve body material. The valve body and the valve cover can be connected by adopting a bolt 5 and a nut 6 which are matched with each other, a sealing spigot is arranged, and the valve body and the valve cover are sealed by adopting a sealing gasket 7. Because the valve body is internally provided with the anti-impact throttling sleeve, the inner cavity is large, the mechanical processing is convenient, and the welding is convenient. The valve body is internally provided with a spigot matched with the valve seat (the valve seat is arranged on the spigot, a valve seat sealing gasket 15 can be arranged between the valve seat and the spigot), and a guide part matched with the throttling sleeve ensures the coaxiality of the installation of the valve seat and the throttling sleeve.

The valve cover adopts an integral forging structure, has the advantages of high forging strength, good mechanical property, simple structure, light weight and the like, and effectively ensures various performances required by the valve cover. The lower end of the valve cover is provided with an outer spigot which is matched with the inner spigot at the top end of the valve body to automatically center, the outer wall of the upper part of the valve cover is provided with a spigot used for being connected with a starting execution mechanism, and the top of a middle hole of the valve cover is provided with a packing chamber used for installing

sealing packing

2 and 3.

The packing gland 1 and the pressing plate 21 adopt a split structure, so that the valve rod is convenient to center and install.

The throttling sleeve adopts a spraying process, the surface hardness is as high as HRC45, and the anti-scouring performance is good. The outer diameter (outer side surface) of the throttling sleeve is matched with the valve body, and the inner hole of the throttling sleeve is respectively matched with the valve core and the valve rod, so that the matching precision of the valve core and the valve seat is effectively guaranteed. Because the sealing surfaces of the valve core and the valve seat are all contained in the throttling sleeve, the scouring of media to the sealing surfaces of the valve core and the valve seat is effectively reduced, and the service lives of the valve core and the valve seat are prolonged.

A self-sealing structure is arranged between the throttling sleeve and the valve body, a conical surface is arranged at a position 25 shown in figure 2 and is matched with the sealing ring 8, and when a medium enters, under the pressure action of the medium, the surface 25, the surface 26, the surface 27 and the surface 28 of the sealing ring are respectively in close contact with the corresponding surfaces of the throttling sleeve, the valve cover and the valve body to play a sealing role.

The vertical blind hole on the valve body and the inner hole of the throttling sleeve are mutually communicated to form a valve rod hole, the inner hole of the throttling sleeve is regarded as the valve rod hole in the corresponding area in the axial area provided with the throttling sleeve, the vertical blind hole of the valve body is the valve rod hole in the corresponding area in the axial area without the throttling sleeve, one part of the valve rod hole is used for penetrating through a valve rod, and the other part of the valve rod hole is used as a medium flow passage. The valve rod hole can be regarded as a main body part of the valve cavity, the valve rod hole is divided into an upper section, a middle section and a lower section of cylindrical holes which can be respectively called as an upper cavity, a middle cavity and a lower cavity, the middle cavity also comprises an annular gap positioned outside the throttling sleeve, the annular gap can also be regarded as a medium inlet channel and enters a pressure-equalizing buffer part of the middle cavity in the throttling sleeve, the aperture of the upper section and the lower section of the cylindrical holes of the valve rod hole can be the same, and the expansion of the middle cylindrical hole is increased.

The throttling sleeve is arranged in the middle of a valve rod hole and is provided with two symmetrical throttling holes 35, a medium in an annular gap outside the throttling sleeve flows into the throttling sleeve through the throttling holes, the bottom surface of an inner flange 36 at the top of the throttling sleeve is provided with an annular conical surface 23 which is a sealing surface and is used for being matched with a sealing surface (an upper sealing surface) 37 of an annular flange on a valve rod to form an upper sealing pair.

The throttling sleeve is arranged, the medium flow direction of the valve adopts a high inlet and low outlet mode, after the medium enters the valve body, the medium firstly enters the inner cavity through the throttling hole of the throttling sleeve and then passes through the sealing surface of the valve core, and during the flowing period of the medium, when the medium passes through the throttling hole, the medium is flushed, the energy is consumed, and the sealing surface is protected.

The valve core is designed as follows:

1) the valve core is of a rotary body structure, two annular flanges (an upper flange 30 and a lower flange 31) are arranged at the position with the largest diameter of the valve core from top to bottom, and the outer side surfaces of the upper flange and the lower flange are preferably cylindrical surfaces and play a double-guide role under the matching of the throttling sleeve. The clearance between the upper flange and the lower flange and the inner hole of the throttling sleeve is controlled in design and processing, so that the concentricity of the valve core and the axis of the valve can be kept in the opening and closing process of the valve core, and the centering performance of the valve core is effectively ensured.

2) The axial distance between two end faces of the upper flange and the lower flange, which are farthest away, is larger than the maximum linear size of an outlet of the medium flowing out of the valve cavity, the annular conical surface at the lower end of the valve core forms a sealing surface (a lower sealing surface), the lower sealing surface of the valve core and the sealing surface of the valve seat are both contained in the throttling sleeve to jointly form a pressure reducing structure of the valve core, and the flushing of the medium to the sealing surface can be effectively reduced. The specific process is as follows: when the valve core is slightly opened, a medium is subjected to primary pressure reduction through a throttling hole flow channel (flow channel I) of the throttling sleeve, then enters a flow channel (flow channel II) between the valve core and the inner wall of the throttling sleeve for secondary pressure reduction, is subjected to tertiary pressure reduction in a flow channel (flow channel III) between a sealing surface of a flowing valve seat and a sealing surface (lower sealing surface) of the valve core, and enters the downstream (lower cavity) of the valve seat; the valve core is continuously lifted, when the opening degree of the lower flange of the valve core exceeds the lower edge (the lower edge of the throttling hole) of the flow channel I, the medium flows into the throttling sleeve, the flow channel II between the valve core (the lower flange) and the inner wall of the throttling sleeve is opened, and the medium flows into the valve seat; under the decompression of the flow channel I, the minimum overflow area of the flow channel II is always smaller than that of the flow channel III, so that a medium erosion area can be effectively transferred from a sealing surface between the valve seat and the valve core to a lower flange area of the valve core, and the erosion of the sealing surface of the valve seat is effectively reduced; similarly, when the valve core is continuously opened to the full-open position, the valve core is completely contained in the anti-scouring throttling sleeve, the medium can not directly scour the sealing surface, the erosion of the sealing surface of the valve core is reduced under the double protection of the pressure reduction through the flow channel I, and the tightness of the valve and the service life of the valve are effectively ensured.

3) The valve rod is connected with the valve core in a mortise and tenon joint structure (an inserting structure), and can also be connected in other movable connection modes allowing small swing. For example, the lower end of the valve rod is a tenon-shaped axial outward-extending end, a U-shaped groove matched with the axial outward-extending end in shape is arranged in the inner hole of the valve core, the axial outward-extending end and the U-shaped groove are mutually inserted to form a tenon-and-mortise structure node, and a gap enough for enabling the valve core to deflect a certain angle relative to the valve rod is reserved between the axial outward-extending end and the U-shaped groove, so that the valve core can keep enough adjustment amount in the action.

For example, an annular groove 32 is formed in the outer diameter of the valve rod, a valve core annular groove 33 matched with the valve rod annular groove is formed in the inner hole wall of the valve core, a pin hole 27 is further formed in the valve core and communicated with the valve core annular groove, the axis of the pin hole and the central line of the valve core annular groove are located on the same cross section of the valve core and tangent to each other, the pin hole penetrates through the single side wall of the valve core, an annular pin (or called round pin) 18 is arranged between the valve rod annular groove and the valve core annular groove, the valve core and the valve rod are in floating connection through the round pin, the head of the valve rod is in an arc shape, a proper gap is formed between the outer diameter of the valve rod and the inner hole of the valve core, the valve core can have a certain swinging amount relative to the valve rod, and has a certain adjusting amount when being in contact with the sealing surface of the valve seat, and can be automatically aligned.

4) An annular flange 24 protruding outwards in the radial direction is arranged on the valve rod of the throttling sleeve, the top (upper end face) of the annular flange is an annular outer conical surface 37 with a large upper part and a large lower part, a valve rod sealing surface is formed, an inner hole taper angle 23 (annular conical surface) of the throttling sleeve and the outer conical surface of the annular flange form an upper sealing pair (or a reverse sealing pair), and the annular conical surface and the outer conical surface of the annular flange can be formed by surfacing welding hard alloy and then machining. In the embodiment, the lower edge of the inner hole of the throttling sleeve is processed into a conical surface with a cone angle of 90 degrees, the conical surface and the outer conical surface of the annular flange form an upper sealing pair, when the valve is in a full-open position, the pressure of the middle cavity is increased, the annular flange is pressed to the throttling sleeve, the upper sealing plays a role, the medium pressure borne by the filler is approximately zero, the sealing between the valve rod and the filler position is effectively ensured, and the service life of the filler is prolonged.

5) Each sealing surface of the valve core is processed after surfacing of hard alloy, preferably cobalt-based hard alloy is surfaced, the cobalt-based hard alloy is suitable for being used as the sealing surface of the valve working under high temperature and high pressure, an EDCoCr-B-03 (D802) welding rod can be used, manual arc welding is adopted, the hardness of the surfaced sealing surface reaches more than 44HRC, and the valve core can be used in a working environment with PN less than or equal to 60Mpa and t less than or equal to 670 ℃; and Co104 (wire 112) is used for surfacing, manual argon arc welding or manual oxyacetylene welding is adopted, the surfacing hardness of a sealing surface reaches 45-50 HRC, and the surfacing welding can be used in a working environment with PN being less than or equal to 80Mpa and t being less than or equal to 670 ℃. Practice proves that the cobalt-based hard alloy is adopted as the sealing surface, so that the wear resistance, the erosion resistance and the long service life are realized. The sealing surfaces of the valve seat and the upper valve seat can also be prepared in the same way as the sealing surface of the valve core.

The included angle (cone angle) of the sealing surface of the valve seat is larger than or smaller than the included angle (cone angle) of the sealing surface of the valve core. In this embodiment, the included angle of the sealing surface of the valve seat is 60 °, and the included angle of the sealing surface of the valve element is 58 °. The valve core and the valve seat have an angle difference of 2 degrees, and the valve core and the valve seat also have a hardness difference of 6-10 HRC. The valve core and the valve seat form a sealing line with a certain width after elastic deformation, and under the same sealing force, larger sealing specific pressure is generated, and the sealing is easier.

The valve body also comprises a medium inlet branch pipe 10 and a medium outlet branch pipe 13, wherein a medium inlet channel 11 and a medium outlet channel 14 are respectively arranged in the medium inlet branch pipe and the medium outlet branch pipe, the two medium channels are communicated with the valve rod hole, the position where the medium inlet channel is communicated with the valve rod hole is higher than the position where the medium outlet channel is communicated with the valve rod hole, the centers of the cross sections of the outlet of the medium outlet channel and the inlet of the medium inlet channel are positioned in the same horizontal plane, and the connecting line of the two is a horizontal line.

The central axes of the medium inlet channel and the medium outlet channel are coplanar with the central axis of the valve rod hole (reducing circular hole), the central axes of the two medium channels are parallel and obliquely arranged, and an included angle of 15-20 degrees is formed between the central axes and the horizontal plane, so that the flow resistance of the valve is reduced to the maximum extent.

The axial span (or height) of the valve core or the distance from the lower edge of the lower flange of the valve core (the lowest point of the lower flange) to the top surface of the valve core is preferably not greater than the distance from the bottom surface of the inner flange of the throttle sleeve to the upper edge of the throttle hole (the highest point of the throttle hole). When the valve is opened, the part of the valve core from the lower flange to the upper part is completely higher than the position where the medium inlet channel is communicated with the valve rod hole, the valve core does not influence the medium circulation, and the sealing effect (upper sealing effect) at the position of the valve filler under the full-open state of the valve can be ensured.

The sealing surface of the valve seat can be subjected to Co106 surfacing welding, and the valve seat can be processed for multiple times and is convenient to repair on line or returned to a factory. The surfaces of the valve rod and the valve core can be subjected to hardening treatment, the valve rod and the valve core can be made of materials which are different according to different media and parameters, the materials can be 20Cr13, F316, F304, 25Cr2MoVA, 25Cr2Mo1VA, 22Cr12NiWMoV, X35CrMo17, NO7750, NO7718 and the like, and the valve core can also be made of 12 Setaili as a whole.

The sealing part of the valve rod, which is in contact with the filler, can be subjected to surface treatment such as extrusion polishing treatment, nitriding treatment, carburizing treatment, carbonitriding treatment and the like, so that the wear resistance, scratch resistance and corrosion resistance of the valve rod are effectively enhanced.

The utility model discloses a theory of operation:

when the valve is closed, under the pushing of the actuating mechanism and the acting force of the medium, the friction force of the filler is overcome, and the valve rod moves downwards; when the sealing surfaces are in contact, the valve is closed. The force exerted by the actuator (drive) is sufficient to ensure that a sufficient sealing force is always maintained on the sealing surfaces. Since the valve is designed such that the medium enters the valve body from above the valve seat, i.e. high in and low out, the maximum force occurs at the moment of opening the valve.

The sealing surface of the base hard alloy is ground, the surface roughness can reach Ra0.1 mu m, the sealing surface is always kept tight under the action of sealing force without internal leakage, and then the filling part only bears the action of medium pressure behind the valve, and the filling is kept sealed by the pressure of the filling gland.

When the valve is opened, the actuating mechanism generates an upward thrust, the direction of the upward thrust is opposite to that of the medium acting force, the valve is opened after the medium acting force and the filler friction force are overcome, when the upper sealing surface of the annular flange is in sealing contact with the throttling sleeve (forming an upper seal), the valve is completely opened, the upper seal can prevent the medium from scouring the filler, and the safety protection effect is achieved.

When the valve is closed, the actuating mechanism generates a downward thrust, and the direction of the downward thrust is consistent with the direction of the medium acting force; under these two forces, the frictional forces of the packing are overcome, eventually producing sufficient sealing force on the sealing surfaces. When the sealing surface of the valve core is contacted with the sealing surface of the valve seat, the sealing surface has an angle difference of 2 degrees; the metal on the sealing surface is elastically deformed to form a narrow sealing line, and the narrow sealing line enhances the reliability of valve sealing.

The utility model discloses a new construction valve compares in traditional hydrophobic stop valve, and nominal pressure and service temperature all improve to some extent, and the range of application is wide.

In the present specification, the terms "upper" and "lower" are used with respect to fig. 1 only for convenience of describing the relative positional relationship of the components, and are not intended to limit the specific structure of the present invention.

The preferred and optional technical means disclosed in the present invention can be combined arbitrarily to form a plurality of different technical solutions, except for the specific description and the further limitation that one preferred or optional technical means is another technical means.

Claims

1. The power station drainage cavitation erosion-resistant anti-scouring stop valve comprises a valve body and is characterized in that a vertical valve cavity is arranged in the valve body, a valve seat and an upper sealing valve seat are arranged in the valve cavity, the valve seat and the upper sealing valve seat divide the valve cavity into an upper cavity, a middle cavity and a lower cavity, the valve seat is positioned between the middle cavity and the lower cavity, the upper sealing valve seat is positioned between the upper cavity and the middle cavity, a valve core is positioned in the middle cavity and is in sliding fit with the middle cavity, a valve rod penetrates through the upper cavity, the lower end of the valve rod is connected with the valve core, the upper end of the valve rod is positioned outside the valve body and is used for connecting a driving device, an annular flange which protrudes outwards in the radial direction is arranged on the valve rod in the middle cavity, the annular flange is positioned above the valve core, a sealing surface of the valve seat faces upwards, and a sealing surface of the upper sealing valve seat faces downwards to respectively form a valve seal and an upper seal with a lower sealing surface of the valve core and an upper sealing surface of the annular flange, the medium inlet channel of the valve is communicated with the middle cavity, the medium outlet channel of the valve is communicated with the lower cavity, the valve seat and the valve body are of a split structure, a valve seat assembling spigot is arranged on the valve body between the middle cavity and the lower cavity, and the valve seat is installed on the valve seat assembling spigot.

2. The hydrophobic anti-cavitation erosion anti-scouring stop valve for the power station comprises a valve body and is characterized in that the valve body is provided with a vertical reducing round hole, the reducing round hole is a blind hole with an open upper end, the aperture of the upper section of the reducing round hole is larger than that of the lower section of the reducing round hole, a valve seat assembling spigot is arranged at the reducing position between the upper section and the lower section of the reducing round hole, a cylindrical throttling sleeve is arranged in the reducing round hole and is positioned in the upper section of the reducing round hole, the bottom surface of the throttling sleeve abuts against the valve seat, the outer side surface of the throttling sleeve is matched with the inner wall of the upper section of the reducing round hole, the inner diameter of the throttling sleeve is larger than that of the lower section of the reducing round hole, an expansion section is further arranged in the reducing round hole, the expansion section is axially positioned between the upper end of the throttling sleeve and the bottom end of the valve seat, the aperture of the expansion section is larger than that of the throttling sleeve, and an annular gap allowing a medium to flow through is reserved between the inner wall of the expansion section and the throttling sleeve, the side wall of the throttling sleeve is provided with a radial throttling hole communicated with the annular gap, the inner end of a medium inlet channel of the valve body is communicated with the annular gap, the inner end of a medium outlet channel of the valve body is communicated with the lower part of the lower section of the reducing circular hole, the throttling sleeve is internally provided with a valve core, the valve core is in a shape of a rotary body, is provided with a top surface and a bottom surface and is in a waist shape, the upper part and the lower part of the side surface of the valve core are respectively provided with an upper flange protruding outwards in the radial direction and a lower flange protruding outwards in the radial direction, the outer side surface of the upper flange and the outer side surface of the lower flange are cylindrical surfaces, the diameters of the upper flange and the lower flange are equal, the upper flange and the lower flange are in sliding fit with the inner wall of the throttling sleeve, the top opening of the throttling sleeve is provided with an inner flange protruding inwards in the radial direction, the valve rod penetrates through the top opening of the throttling sleeve, the lower end of the valve core is connected with the upper end outside the valve body, and the valve rod inside the throttling sleeve is provided with an annular flange protruding outwards in the radial direction, the annular flange is positioned above the valve core, the top of the valve seat and the bottom of the valve core are respectively provided with mutually matched sealing surfaces, the bottom of the inner flange and the top of the annular flange are respectively provided with mutually matched sealing surfaces, a top opening of the valve body is fixedly provided with a valve cover, and the valve cover is provided with a middle hole through which the valve rod can pass.

3. The hydrophobic anti-cavitation erosion and anti-scouring stop valve for the power station as claimed in claim 2, characterized in that the valve core is provided with a blind valve rod hole with an open upper end, the lower end of the valve rod extends into the blind valve rod hole, and an annular pin for connecting the outer side surface of the valve rod in the blind valve rod hole and the inner wall of the blind hole is arranged between the outer side surface of the valve rod and the inner wall of the blind hole.

4. A hydrophobic anti-cavitation erosion and erosion stop valve for a power plant as claimed in claim 2, characterised in that the lower end surface of the valve stem is a convex surface of revolution.

5. A hydrophobic anti-cavitation erosion-proof stop valve for a power station as claimed in claim 2, characterized in that the outer side of the throttling sleeve is a reducing cylindrical surface, the outer diameter of the upper section is smaller than that of the lower section, the reducing part between the upper section and the lower section is positioned above the expansion section, so that an annular gap is formed between the upper section and the reducing circular hole, a sealing ring is arranged in the annular gap, an annular cylindrical protrusion which extends downwards and into the annular gap is arranged at the bottom end of the valve cover, and the annular cylindrical protrusion is tightly pressed on the sealing ring.

6. A hydrophobic anti-cavitation erosion-proof stop valve for power station as claimed in claim 2, characterized in that the top of the valve body and the bottom of the valve cover are respectively provided with fitting spigots which are mutually matched, and a sealing gasket is arranged between the fitting spigots which are mutually matched.

7. The hydrophobic anti-cavitation erosion and anti-scouring stop valve for the power station of claim 2, characterized in that a packing chamber is arranged between the top inner wall of the central hole of the valve cover and the valve rod, the packing chamber is filled with packing for sealing or provided with a sealing element, the top of the valve cover is provided with a packing gland, the packing gland is in a shape of a revolution body, the upper part of the outer side surface of the packing gland is provided with an annular packing gland flange which is outwards protruded in the radial direction, the top surface of the annular packing gland flange is in an umbrella shape, a pressing plate is arranged above the packing gland, the bottom of the pressing plate is provided with a conical concave surface corresponding to the top surface of the annular packing gland flange, the pressing plate is pressed on the top surface of the annular packing gland flange, and the pressing plate is fixedly connected with the valve cover.

8. A plant trap water anti-cavitation erosion and anti-scouring stop valve as claimed in claim 2, characterised in that the sealing surface of the top of the valve seat and the sealing surface of the bottom of the spool are both conical.

9. A hydrophobic anti-cavitation erosion stop valve for a plant as claimed in claim 8, characterised in that the inner edge of the sealing surface of the bottom of the spool is located radially inwardly of the inner edge of the sealing surface of the top of the valve seat and the outer edge is located radially outwardly of the outer edge of the sealing surface of the top of the valve seat, the cone angle of the sealing surface of the bottom of the spool being different from the cone angle of the sealing surface of the top of the valve seat.

10. The hydrophobic anti-cavitation erosion-proof anti-scouring stop valve for a power station of claim 2, wherein the sealing surface at the bottom of the inner flange is a conical surface with a small top and a large bottom, the outer edge of the sealing surface is connected with the horizontal bottom surface of the inner flange, the inner edge of the sealing surface is connected with the cylindrical inner side surface of the throttling sleeve, and the sealing surface at the top of the annular flange is a conical surface with a small top and a large bottom.