CN1048093A - Improved Throttle - Google Patents

Abstract

A throttle valve for preventing damage to the valve surface, which includes: a valve body with an inlet pipe for introducing liquid or gas, an outlet pipe for discharging liquid or gas, and a valve port supporting a valve stem; , an annular sealing mechanism between the outlet; and a retractable valve plug for opening and closing the fluid between the inlet and outlet pipes, the valve plug has a tip that slides with the sealing mechanism and has a contour shape determined by an exponential equation Head, which directs the fluid toward the center of the outlet tube so that vaporization and cavitation of the liquid occurs away from the plug surface and the outlet tube wall.

Description

Improved throttle valve

The present invention relates generally to a kind of improved design that prevents the throttle valve that valve surface damages.Specifically, The present invention be directed to and prevent because the corrosion that liquid vaporization suddenly and gassing implosion subsequently cause and cavitation phenomenon.

Throttle valve is used for the various occasions that high pressure drop is arranged of chemical industry, petroleum industry and utility industry, comprising: continuous blowdown sampling, high pressure ventilation, turbo machine draining and boiler feed pump bypass release of pressure etc.The heavy valve that uses under harsh conditions has purposes widely.Abrasive condition is not lasting usually.Generally certain when work occurs in a flash, and every day or jede Woche have only several times.This valve is used for stop and the throttle valve draining and the ventilation of reheater, reheater and superheater draining, steamturbine usually as high pressure and low-pressure drainage and heat-riser valve.

Throttle valve is often because its pith generation burn into cavitation erosion and wire drawing and damage fast.Cavitation phenomenon forms bubble exactly suddenly and breaks in quick flowing liquid.A kind of cemented carbide dish that valve surface damaged reduce to minimum throttle valve applications and scribble the cylindrical valve seat of resistant material.The fluid of dish and the annulus of valve base chamber of flowing through quickens before the butt end of arrival dish equably, behind the butt end of arrival dish, the liquid flow area of runner center increases, make runner heart portion produce pressure and fall, thereby vaporize in the fluid that one deck of along the continuous-flow of valve seat wall in the cylindrical valve seat is not vaporized.

The problem that this throttle valve is run into usually is that when liquid medium flow through the outlet of valve, the pressure that causes in valve fell and can make liquid medium that vaporization and cavitation phenomenon take place.Cavitation erosion usually occurs in some position on throttle valve surface and damages the surface at these positions.Owing to designed dish and valve seat, the valve surface that is exposed in the air pocket that disk butt end place produces must be coated high-abrasive material, and still, the cost of coating high-abrasive material on these surfaces is expensive.

Therefore, hope can have a kind of such throttle valve, and it can guide fluid to leave the internal surface of valve body and some member, so that the damage that cavitation erosion is caused reduces to minimum.

And, more being desirable to provide the throttle valve of a kind of its valve plug contour shape by the exponential equation regulation, it can be left the internal surface of valve by the plug guidance fluid.

Therefore, an object of the present invention is to provide a kind of throttle valve that designs for use under the harsh conditions specially, vaporization takes place and produces the position of cavitating subsequently in the liquid medium that it can limit the surface of leaving valve.

Another object of the present invention provides a kind of throttle valve, and it can make liquid medium quicken by the little cross section passage that connects big cross section passage after, any vaporization and cavitation phenomenon can not take place thereby make in the lip-deep certain position of valve.

Another purpose of the present invention provides a kind ofly has only a spot of valve surface requirement to coat the throttle valve of wear resistant coating, thereby reduces the manufacture cost of valve.

A further object of the present invention provides a kind of multiduty throttle valve, the slurry that its energy conveying gas, liquid, water and steam mixture or liquid mix with abrasive material, and not etch and damage valve seat and valve plug.

A further object of the invention provides a kind of energy and adapts to the throttle valve with the liquid of cavitation effect and flash evaporation, the liquid that contains suspended particle and two-phase liquid.

According to the present invention, a kind of throttle valve that can prevent that valve surface from damaging has been proposed, this valve comprises a valve body, has a valve port that is used for supporting valve rod and one on the valve body gas or liquid medium are introduced inlet tube in the valve and one gas or the external outer pipe of liquid expulsion valve.Be provided with a lip ring between import in valve body and the outlet.Throttle valve of the present invention also comprises, a telescopic valve plug, and it is installed in the valve and can slidably reciprocates, and is used for opening and closing the liquid stream between inlet tube and the outer pipe.The pointed nose that this valve plug has a contour shape to be determined by the exponential equation of complexity.This pointed nose cooperates slidably with above-mentioned sealing mechanism, and its profile can be guided the fluid of output the center to above-mentioned outer pipe.Throttle valve of the present invention has two kinds of shapes, and a kind of is rectilinear, and a kind of is angled, and the outlet port of lineal shape valve is provided with a kind of hardboard of dismountable band barrier coating.

In conjunction with the accompanying drawings, can understand top general introduction and following detailed description better.In order to demonstrate the invention, accompanying drawing illustrates a most preferred embodiment, but must understand that the present invention is not limited to described concrete structure and method.

Fig. 1 is the time lag sectional drawing of most preferred embodiment under the opening and closing state of throttle valve of the present invention;

Fig. 2 and 2A are the Schedules of the valve plug pointed nose profilogram of most preferred embodiment shown in Figure 1;

Fig. 3 is the exponential equation of profilogram of the valve plug of Fig. 1 most preferred embodiment;

Fig. 4 is the sectional drawing of the second embodiment of the present invention.

Below with reference to accompanying drawing the present invention is described.Same part is marked with same label in the accompanying drawing.Referring to Fig. 1, this figure is that throttle valve 10 of the present invention is in the cross-section front view under the opening and closing state.Throttle valve 10 of the present invention has one by the valve body 12 that forges or the casting heat-resistant carbon steel is made, and the shaped design of valve becomes angled, and can make according to the needs of concrete industry.Valve body 12 has an inlet tube 13 and an outer pipe vertical with it 15, is used for liquid is imported and draw throttle valve.Valve body 12 also comprises a bonnet 14, by lock nut 17 it is abutted on the pressure seal.Lock nut 17 is blocked by bolt 17a.Bonnet 14 has a guide ring that hardens 11 by heat-resisting low alloy steel manufacturing in its lower end, is used for valve plug is carried out the friction guiding.The axial component of bonnet 14 has hole 16, in order to clamping valve rod 18.Space between the top in hole 16 and the valve rod 18 stuffing box gland 20 of packing into makes and strengthens gland 22 and compress sealing cover 20 by being screwed into sealing nut 21.Guide bush 23 is supporting valve rod 18.Bonnet 14 is by eccentric circular ring 27 and supporting ring 25 supporting location.

Bonnet 14 has cylindrical cavity 24, when the main body of valve plug 26 raises, just in time enters in the cavity 24.Inlet tube 13 extends out from the sidewall of valve body 12, and communicates with liquid medium that will enter throttle valve or slurry source.All kinds of materials all can pass through this valve, comprise the suspension that water and steam mixture or liquid and abrasive material are formed.

Outer pipe 15 is positioned at the lower end of valve body 12, and the liquid that overflash takes place is from discharging here.The circular cone that is shaped as of outer pipe 15 is expanded shape.Adopt this shape can prevent second cavitation effect, and prevent the wearing and tearing of outer pipe 15 by cemented carbide sclerosis surface layer.

Valve body has a lip ring 32 between inlet tube and outer pipe, it is made up of an outer ring valve seat 34 and an inner annular valve seat 32 that inserts in the outer ring valve seat 34.When valve plug 26 was in the closed position, ring- shaped valve seats 32,34 sealed; And when being shown in an open position when valve plug withdrawal, they then become a bypass, and the liquid medium that passes through is constantly quickened along flowing out direction.Outer ring valve seat 34 is soldered in the valve body 12, and is adjacent with outer pipe 15.An internal surface 36 of inner annular valve seat 32 stretches out from an end along updrift side, and second internal surface 38 then stretches out along downstream direction.

Because inner annular valve seat 32 moves in the ring-shaped valve seats 34 outside, so form a gap 40 between two ring-shaped valve seatss.Therefore, when the liquid of extreme temperatures (500～1000) or gas medium by throttle valve 10 and when flowing through inner annular valve seat 32, the existence in gap 40 just allows inner annular valve seat 32 that thermal expansions take place or valve body 12 deforms.And, when being soldered to outer ring valve seat 34 in the valve body 12 owing to extreme temperatures makes valve seat 34 thermal expansion takes place.Only on internal surface 36,38, scribble the good material of wear-resisting property, for example Tungsten carbite, chromium carbide or cemented carbide.When making this valve, earlier two valve seat parts are linked to be an integral body, carry out putting into and be soldered to valve body 12 again after the machining.

Set forth the valve plug 26 of most preferred embodiment below.Valve plug 26 guiding liquids media flow on the special position in inner annular valve seat 32 downstreams.In the present embodiment, valve plug 26 comprises a common cylindrical body, and its upper end is connected with valve rod 18, and the lower end has a pointed nose 42.Valve plug 26 is driven by valve rod 18 and upwards slips in the cavity 24 of bonnet 14, and its pointed nose 42 has the accurate arc outer wall of profile, and its curve reduces gradually with respect to the central shaft curvature of a curve of valve body 12.The contour shape of valve plug pointed nose 42 is determined by curve shown in Figure 2 and following equation shown in Figure 3:

$\mathrm{Y\; =\; A\; +}\frac{\mathrm{(\; V\; -\; A\; )}}{U^{\mathrm{WU\; /\; (\; V\; -\; A\; )}}}{\mathrm{\times \; (\; U\; -\; X\; )}}^{\mathrm{W\; U\; /\; (\; V\; -\; A\; )}}$

In the formula: A=(D)/2, D are the diameter at valve plug tip;

V＝S×C ₁;

U＝S×C ₂;

Wherein, C ₁And C ₂Be constant, C ₁=0.1～5.0, C ₂=0.5～5.0; S is the distance of the minimum diameter place of interior valve seat to the valve plug central axis; W=C ₃, C wherein ₃=0.1～2.0; X is a stroke, and this stroke equals the nominal size of valve.

The arc outer wall of valve plug 26 is pressed downbeam guiding liquids MEDIA FLOW from valve plug surface, and prevents that liquid stream from distorting.Valve plug 26 useful ceramics materials are made, and its outer surface should be coated with the Tungsten carbite or the chromium carbide 41 of the thin and smooth high abrasion of last layer.The runner of valve seat carries out surface hardening with for example alloy material such as Stellite 6 or Hayens 25.The liquid flowing speed vector that is produced is outside from the profile of valve plug.Valve plug 26 can provide the linearity control characteristic, but when beginning a minimum dead zone is arranged.Because it has this linear performance,, leak the rate of oozing thereby reduce the gap so can reduce the size of valve seat.If require to have indicial response when using, then can in positioning work piece, use a cam or adopt the electronic control way to obtain.

Throttle valve 10 also comprises an abducent outer pipe 15 of taper shape, and its cross-section area is bigger than inner annular valve seat 32, and this zone is one may produce the position that cavitation phenomenon takes place then in vaporization.The main wall 43 of outer pipe 15 extends to Way out from inner annular valve seat 32, and is connected with second inwall 44 that is parallel to the valve body extension of central axis.The inwall of outer pipe 15 scribbles the high abrasion material that is similar on first internal surface 36.Since inner annular valve seat 32(with and internal surface 36,38) with outer pipe 15 between cross-section area different, when inner annular valve seat 32 enters cavity 15 so liquid medium is flowed through, big and the unexpected pressure of meeting generation falls and flow velocity is reduced, and this just causes that liquid medium takes place to vaporize and cavitate in its saturation point or near saturation point.And because the liquid medium acceleration is flowed through inner annular valve seat 32(as mentioned above), so more encouraged this phenomenon.Cavitation phenomenon will be in valve body 12 takes place on the privileged site in the downstream of valve plug 26 in the result, rather than taking place on the position that prevents damaged surfaces through special processing at valve seat.

Fig. 4 illustrates the embodiment of the Y type path that another kind of the present invention can Gong select for use.In this embodiment, inlet tube is parallel with outer pipe basically, and its cypriot valve components and valve component laterally reach inlet tube and outer pipe place, valve body 12 ' make with heat-resisting low-alloy carbon steel die forging or casting.Bonnet assembly 14 ' with first embodiment is the same.This embodiment also is equipped with the hardboard 58 of a band corrosion-inhibiting coating at its outlet position, this piece plate pins with the ring part clamping and with bolt 17a.

Working condition below with reference to description of drawings throttle valve of the present invention.The control valve that throttle valve of the present invention uses down as mal-condition is in order to gas, liquid, water and steam mixture of carrying High Temperature High Pressure and the slurry that liquid mixes with abrasive material.This throttle valve has prevented that from design the surface of valve is because of the damage of corroding and cavitation erosion causes.

Enter throttle valve 10 from the liquid medium in liquid source inlet and the inlet tube 13 by valve.Under complete closing state, the pointed nose 42 of valve plug 26 engages with inner annular valve seat 32, forms a locking system that can stop any liquid by throttle valve 10.

Drive valve rod 18 along moving to open position on the Y with a kind of common actuating mechanism, (this moment, valve plug 26 receded in the cavity 24 of bonnet 14), thus make valve plug 26 break away from inner annular valve seats 32, and allow flow of liquid to cross throttle valve 10.

The liquid of inlet tube 13 of flowing through is crossed inner annular valve seat 32 by valve plug pointed nose 42 downward directed stream.The profilogram of valve plug pointed nose is determined by following exponential equation:

$\mathrm{Y\; =\; A\; +}\frac{\mathrm{(\; V\; -\; A\; )}}{U^{\mathrm{WU\; /\; (\; V\; -\; A\; )}}}{\mathrm{\times \; (\; U\; -\; X\; )}}^{\mathrm{W\; U\; /\; (\; V\; -\; A\; )}}$

In the formula, A=(D)/2, D are the diameter at valve plug tip;

V＝S×C ₁;

U＝S×C ₂;

C wherein ₁And C ₂Be constant, C ₁=0.1～5.0, C ₂=0.5～5.0;

S is the distance of interior valve seat minimum diameter place to the valve plug central axis;

W=C ₃, C wherein ₃=0.1～2.0;

X is a stroke, and this stroke equals the nominal size of valve.

When flow of liquid is crossed first internal surface 36 of inner annular valve seat 32, because reducing continuously, this surperficial cross-section area constantly quickens, when liquid medium arrived the section start of second internal surface 38 of inner annular valve seat 32, it is maximum that flow velocity reaches.When liquid stream flows to outer pipe 15 and when second internal surface 38, its cross-section area then increases continuously.Owing to take place to change suddenly from cross-section area first internal surface, 36 to second internal surfaces 38, thereby fall and cause liquid medium vaporization and cavitation effect subsequently to take place so produced rapid pressure, but the contour shape of valve plug pointed nose 42 can be guided liquid stream and the bubble that forms enters cavity 46 downwards and leave the surface of pointed nose 42 in its saturation point or near saturation point.

Implosion takes place in the formed bubble of cavitation phenomenon in scribbling the cavity 46 that prevents the coating damaged, subsequently, the mixture of liquid and gas is from the outlet discharge.

(Fig. 1) in the present embodiment, inlet tube 13 and outer pipe 15 are respectively equipped with flange 54 and 56, to help the connection of throttle valve.But, must understand, can select any suitable mounting mechanism for use according to the difference of the system that uses throttle valve.

In another kind of embodiment, valve plug and valve component are also worked in a similar fashion.But it has an anti abrasive connecting plate 58, can prevent that valve body from receiving the damage of the liquid of cavitation effect.

The people that present technique is familiar with will understand, under the situation that does not break away from basic principle of the present invention, can carry out some modification to the foregoing description, therefore, it is also to be understood that, the present invention is not limited to described specific embodiments, and it should be included in the various remodeling of being done under the scope and spirit of stipulating in the appended claims.

Claims (11)

1, a kind of throttle valve that prevents that valve surface from damaging, it comprises:

A valve body, this valve body have one to be used for liquid medium is introduced inlet tube in the valve and an outer pipe and a valve port that is used for supporting telescopic valve rod of liquid being discharged the outer taper shape expansion of this valve body;

Ring packing mechanism in above-mentioned valve body between above-mentioned import and outlet;

A telescopic valve plug that is used for opening and closing the liquid stream between inlet tube and the outer pipe, this valve plug has a pointed nose with contoured that is slidingly matched with above-mentioned sealing mechanism, this pointed nose has contoured so that guide the liquid conductance center of outer pipe into, thereby makes the vaporization of aforesaid liquid and cavitation phenomenon occur in the place of leaving above-mentioned outlet tube wall.

According to the throttle valve of claim 1, it is characterized in that 2, described sealing mechanism comprises an outer ring valve seat and an inner annular valve seat that inserts this outer ring valve seat.

According to the throttle valve of claim 2, it is characterized in that 3, described outer ring valve seat is welded on the above-mentioned valve body.

According to the throttle valve of claim 2, it is characterized in that 4, the contour shape of above-mentioned valve plug pointed nose is determined by following exponential equation:

$\mathrm{Y\; =\; A\; +}\frac{\mathrm{(\; V\; -\; A\; )}}{U^{\mathrm{WU\; /\; (\; V\; -\; A\; )}}}{\mathrm{\times \; (\; U\; -\; X\; )}}^{\mathrm{W\; U\; /\; (\; V\; -\; A\; )}}$

In the formula: A=(D)/2, wherein D is the diameter at valve plug tip;

V＝S×C ₁;

U＝S×C ₂;

C wherein ₁And C ₂Be constant, C ₁=0.1～5.0, C ₂=0.5～5.0;

S is the distance between interior valve seat minimum diameter place and the valve plug central axis;

W=C ₃, C wherein ₃=0.1～2.0;

X is a stroke, and this stroke equals the nominal size of valve.

According to the throttle valve of claim 1, it is characterized in that 5, described valve plug surface scribbles high abrasion resisting material.

According to the throttle valve of claim 5, it is characterized in that 6, described high abrasion resisting material is Tungsten carbite or chromium carbide.

7, a kind of throttle valve that prevents that valve surface from damaging, it comprises:

A valve body, this valve body have one liquid medium is introduced plain cylindrical form inlet tube in this valve and one liquid is discharged the outer pipe of the outer taper shape expansion of this valve body and one can to hold valve port with a scalable valve rod of clamping;

Place the ring packing mechanism between interior above-mentioned import of above-mentioned valve body and the outlet;

A telescopic valve plug that passes above-mentioned valve port, this valve plug has a pointed nose that cooperates and have the contoured shape slidably with above-mentioned ring packing mechanism, and this pointed nose has the contoured shape so that fluid is pressed the center of guiding to above-mentioned outer pipe that establish an equation:

$\mathrm{Y\; =\; A\; +}\frac{\mathrm{(\; V\; -\; A\; )}}{U^{\mathrm{WU\; /\; (\; V\; -\; A\; )}}}{\mathrm{\times \; (\; U\; -\; X\; )}}^{\mathrm{W\; U\; /\; (\; V\; -\; A\; )}}$

In the formula, A=(D)/2, wherein D is the diameter at valve plug tip;

V＝S×C ₁;

U＝S×C ₂;

C wherein ₁And C ₂Be constant, C ₁=0.1～5.0, C ₂=0.5～5.0;

S is the distance between minimum place of interior valve-seat diameter and the valve plug central axis;

W=C ₃, C wherein ₃=0.1～2.0;

X is a stroke, and this stroke equals the nominal size of valve.

Therefore, the vaporization of liquid and cavitation phenomenon occur in the place of the tube wall of the taper shape expansion of leaving pointed nose with contoured and above-mentioned outer pipe.

8, a kind of throttle valve that prevents that valve surface from damaging, it comprises:

A valve body, this valve body have one liquid medium introduced inlet tube and an outer pipe that is substantially perpendicular to above-mentioned inlet tube in the above-mentioned valve, and this outer pipe has the madial wall of conical expansion, is used for discharging aforesaid liquid;

Be fixed in the above-mentioned valve body between above-mentioned inlet tube and the outer pipe so that between above-mentioned inlet tube and outer pipe, form the ring packing mechanism of sealing;

A bonnet that is connected with valve body, it has guide groove, in order to the telescopic valve plug of clamping;

A telescopic valve plug that is clamped in the above-mentioned bonnet, it has a pointed nose that has contoured and be slidingly matched with above-mentioned sealing mechanism, in order to open and close the above-mentioned liquid flow medium between inlet tube and the outer pipe, above-mentioned pointed nose with contoured is guided the liquid conductance that flows out in the heart among the outer pipe of above-mentioned conical expansion, thereby makes the vaporization of aforesaid liquid and the place that cavitation phenomenon occurs in the outer pipe inwall that leaves above-mentioned conical expansion.

9, throttle valve according to Claim 8 is characterized in that, the contour shape of described pointed nose by under establish an equation definite:

$\mathrm{Y\; =\; A\; +}\frac{\mathrm{(\; V\; -\; A\; )}}{U^{\mathrm{WU\; /\; (\; V\; -\; A\; )}}}{\mathrm{\times \; (\; U\; -\; X\; )}}^{\mathrm{W\; U\; /\; (\; V\; -\; A\; )}}$

In the formula, A=(D)/2, wherein D is the diameter at valve plug tip;

V＝S×C ₁;

U＝S×C ₂;

C wherein ₁And C ₂Be constant, C ₁=0.1～5.0, C ₂=0.5～5.0;

S is the distance between minimum place of interior valve-seat diameter and the valve plug central axis;

W=C ₃, C wherein ₃=0.1～2.0;

X is a stroke, and this stroke equals the nominal size of valve.

10, a kind of throttle valve that prevents that valve surface from damaging, it comprises:

A valve body, this valve body have one liquid medium introduced inlet tube in the above-mentioned valve and an outer pipe that is roughly parallel to above-mentioned inlet tube and has the madial wall of conical expansion, and it is used for discharging the aforesaid liquid medium;

Be fixed on the ring packing mechanism between above-mentioned inlet tube and above-mentioned outer pipe in the above-mentioned valve body, in order to form the sealing between above-mentioned inlet tube and the outer pipe;

A bonnet that is connected with above-mentioned valve body, this bonnet is approximately perpendicular to above-mentioned inlet tube and outer pipe, and has a guide groove that is used for the telescopic valve plug of clamping;

A telescopic valve plug that is clamped in the above-mentioned bonnet, it has a pointed nose that has contoured and be slidingly matched with above-mentioned sealing mechanism, so that open and close the aforesaid liquid MEDIA FLOW between inlet tube and the outer pipe, above-mentioned pointed nose with contoured is guided the liquid conductance center of the outer pipe of above-mentioned conical expansion into, thereby makes the vaporization of aforesaid liquid and the place that cavitation phenomenon occurs in the outlet tube wall that leaves above-mentioned conical expansion;

A dismountable corrosion protection plate, it is installed on the position of above-mentioned outlet port in the face of above-mentioned valve plug and above-mentioned ring packing mechanism.

11, according to the throttle valve of claim 10, it is characterized in that, the contour shape of described pointed nose by under establish an equation definite:

$\mathrm{Y\; =\; A\; +}\frac{\mathrm{(\; V\; -\; A\; )}}{U^{\mathrm{WU\; /\; (\; V\; -\; A\; )}}}{\mathrm{\times \; (\; U\; -\; X\; )}}^{\mathrm{W\; U\; /\; (\; V\; -\; A\; )}}$

In the formula, A=(D)/2, wherein D is the diameter at valve plug tip;

V＝S×C ₁;

U＝S×C ₂;

C wherein ₁And C ₂Be constant, C ₁=0.1～5.0, C ₂=0.5～5.0;

S is the distance between interior valve seat minimum diameter place and the valve plug central axis;

W=C ₃, C wherein ₃=0.1～2.0;

X is a stroke, and this stroke equals the nominal size of valve.

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