Double eccentric ball valve

Abstract

The application provides a double eccentric ball valve, which comprises a valve body, fluid medium inlets and outlets arranged on the valve body respectively, and valve seats arranged at the inlets and outlets; two hemispherical sealing members are arranged in the inner cavity of the valve body, the two hemispherical sealing members are connected to be integrated, the center lines of the two hemispheres are in the same horizontal plane and the distance between the two center lines is a set distance; the upper surface and the lower surface of the inner cavity of the valve body are respectively designed with two pairs of valve rod shaft holes, and the two pairs of shaft holes correspond to the center lines of the two hemispheres respectively. The double eccentric ball valve of the application can overcome the valve sealing leakage caused by spring failure, long-term friction of the sealing member, expansion and contraction of the sealing ring caused by high and low temperature difference and other complex situations, can bear equal pressure in two directions, has double insurance effect in sealing, and will be widely used in the fields of petroleum, chemical industry, natural gas, nuclear power, water supply system and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of valve body, in particular to a double eccentric ball valve. BACKGROUND

[0002] In the current pipeline, we use many ball valves, because the ball valve has the function of cutting off and regulating flow, and after the ball valve is opened, there is no any flow resistance in the inner cavity of the ball valve, and the pipeline is straight through, and no reverse impact force is generated, so the ball valve is widely used in the pipeline, but it still has some weaknesses, the ball and the valve seat rotate and move back and forth on an axis, the ball and the valve seat are in friction for a long time to achieve the opening and closing of the valve, long-term friction can cause the ball and the valve seat to be damaged or become smaller, and corrosive medium can cause the spring to fail, and other reasons can cause the ball valve to lose the sealing function, and the double eccentric two-hemisphere ball valve is two eccentric balls corresponding to two valve seats, and the two hemispheres are offset by 3-15mm from the center line of the pipeline as the reference, and the angle generated by the offset is used to extrude the valve seat, when the closed valve is rotated in the counterclockwise direction at the first time, the ball and the valve seat are separated, and no friction is generated, if the valve seat is small or the spring is invalid under the influence of the working medium environment, the eccentric ball body extrudes the valve seat, and the valve seat is more tightly filled, which fills the above-mentioned loss, the eccentric two-hemisphere ball valve has the advantages of double sealing insurance, and has the characteristics of no leakage, and is more suitable for use in low-temperature environment.

[0003] At present, due to the long-term erosion, corrosion and wear of the working medium, the spring is invalid, the sealing element is small due to friction, the sealing element is expanded due to high and low temperature difference, and many complex conditions cause sealing leakage, which is difficult to maintain, and the pipeline has no safety guarantee. SUMMARY

[0004] In order to solve the above problems, the present application provides a double eccentric ball valve, which comprises a valve body, a fluid medium inlet and an outlet are arranged on the valve body respectively, and valve seats are arranged at the inlet and the outlet; two hemispherical sealing elements are arranged in the inner cavity of the valve body, the two hemispherical sealing elements are connected to form a whole, and the centers of the two hemispheres are apart by a set distance; two pairs of valve rod shaft holes are designed on the upper surface and the lower surface of the inner cavity of the valve body, and the two pairs of shaft holes are arranged on the center lines of the two hemispheres.

[0005] Valve body, mostly circular, straight through, designed with two fluid inlet and outlet holes, each of which is designed with a valve seat, a sealing ring step and a threaded hole. In the lower wall of the valve body cavity, the center line of the pipeline is the reference, and each is offset by 3-15 mm in the opposite direction to design a valve stem hole. The lower end of the hole is designed with a gasket step bottom cover combined threaded hole. The upper wall of the valve body is designed with a valve stem hole that is symmetrical and concentric with the lower wall. The upper end of the hole is designed with a step to prevent the gasket from blowing out and a packing cavity. A bolt hole is designed at the upper end of the packing hole for connecting the packing gland and the bracket. The valve body material can be selected from WCB, CF8, CF3, etc. according to the working medium.

[0006] Two hemispheres (seals); the hemispheres are U-shaped, about one-third of a sphere, one side is designed with an SR spherical surface, the other side is designed with two hexagonal holes and two positioning screws combined with the upper and lower valve stems, the center of the hexagonal hole is offset by 3-15 mm from the center of the SR spherical surface. The eccentricity cooperates with the eccentricity of the upper valve stem hole of the valve body. The material of the two hemispheres can be selected from WCB, CF8, CF3, etc. according to the working conditions. The SR spherical surface can be surfacing with 13Cr, STL, and chemical plating with chromium, nickel, spraying NI60, WC, etc. to improve hardness.

[0007] The valve seat is cylindrical, and the inner diameter of the valve seat is equal to the nominal diameter of the valve body. One end of the valve seat has a flange that matches the inner diameter of the valve body inlet and outlet. The flange is provided with a counterbore and a through hole for connecting with the valve body. The other end of the valve seat is provided with a groove for embedding a sealing ring. The groove is provided with a sealing ring for sealing with the surface of the hemisphere.

[0008] The sealing ring is a circular ring, and the end face is provided with an angle equal to 35° for matching with the spherical surface of the hemisphere.

[0009] The valve seat is cylindrical, and the inner diameter of the valve seat is equal to the nominal diameter of the valve body. One end of the valve seat has a flange that matches the inner diameter of the valve body inlet and outlet. The flange is provided with a counterbore and a through hole for connecting with the valve body. The other end of the valve seat is provided with a hard seal that matches the spherical surface of the hemisphere. The contact surface between the hard seal and the spherical surface is a slope with an angle less than or equal to 45°.

[0010] The hard seal is fixed to the valve seat by surfacing. The material of the hard seal is D507 or STL.

[0011] The valve seat is a disc, and the material can be selected from A105, F304, F316, etc. according to the working conditions. The inner diameter of the valve seat is designed with a circular hole that matches the diameter of the valve. The outer diameter is designed with a flange that matches the inner diameter of the valve body flow channel outlet, and 4-24 counterbores and through holes for installing internal hexagonal screws. The other end is designed with a groove for embedding a sealing ring. A taper can also be designed at this position to match the spherical surface. The taper surface is surfacing with 13Cr, D507, STL, etc. to form a hard seal seat.

[0012] The valve stem includes two pairs of upper and lower valve stems, a bottom cover, two gear plates and a driving device.

[0013] The valve stem is made of 2Cr13, F304, F316, 17-4PH or the like according to the working condition, and is a power transmission part of the valve, including two upper and lower valve stems, one end of the upper valve stem is provided with a hexagonal head matched with a hemisphere, and the other end is provided with a key groove for arranging the gear plate and the driving device, one end of the lower valve stem is provided with a hexagonal head matched with a hemisphere, and the other end is provided with an SR spherical surface in contact with the bottom cover.

[0014] The two pairs of valve stem holes are arranged in alignment and concentricity, and the lower hole is provided with a step for arranging a gasket and a sealing ring and a screw hole for arranging the bottom cover.

[0015] In the embodiment, the center lines of the two circles of the cross section of the two hemispherical sealing members in the xy plane in the x axis direction and the y axis direction are 3-15 mm apart.

[0016] The two gear plates are designed on the two valve stems as power transmission, and the modulus, tooth number and pressure angle of the two gear plates are equal and synchronous.

[0017] The gear material can be cast iron, cast steel, carbon structural steel or alloy structural steel according to the requirement.

[0018] The driving device (worm gear box) rotates the gear plate on the first upper valve stem, and then drives the second upper valve stem through the track on the gear plate, so that the two hemispherical sealing members on the two valve stems are rotated to open and close.

[0019] When the driving device (worm gear box) rotates 90° in the clockwise direction, the two hemispheres in the valve body cavity are in contact with and sealed by the sealing ring, and when it rotates ≥90° in the clockwise direction, the sealing effect is more and more tight, when it rotates 45° in the counterclockwise direction, the two hemispheres are opened by half, and when it rotates 90° in the counterclockwise direction, the two hemispheres are fully opened.

[0020] The double eccentric ball valve has the following characteristics: one valve has two seals, two eccentric shafts (valve stems) in different directions are designed on the axis of one pipeline, when the driving device drives the valve stem to rotate axially, the two hemispheres rotate and are opened or closed respectively.

[0021] The double eccentric ball valve of the present application is invented in view of the long-term leakage of the ball valve in the prior art and the lack of safety guarantee for the pipeline. The double eccentric ball valve can overcome the leakage of the valve caused by the spring failure, the long-term friction of the sealing element, the expansion and contraction of the sealing ring caused by the high and low temperature difference, and can bear equal pressure in two directions. The sealing has a double insurance effect and can be widely used in the fields of petroleum, chemical industry, natural gas, nuclear power, water supply system and the like. BRIEF DESCRIPTION OF DRAWINGS

[0022] Fig. 1 is a half sectional view of the double eccentric ball valve of a preferred embodiment of the present application;

[0023] Fig. 2 is a top view of the double eccentric ball valve of a preferred embodiment of the present application;

[0024] Fig. 3 is a sectional view of the double eccentric ball valve of a preferred embodiment of the present application;

[0025] Fig. 4 is a top sectional view of the double eccentric ball valve of a preferred embodiment of the present application. DETAILED DESCRIPTION

[0026] A preferred embodiment of the present application is described below with reference to the accompanying drawings, which is used to illustrate the implementation of the present application and to introduce the present application to the skilled in the art, so that the technical content of the present application is more clear and easy to understand. The present application can be embodied in many different forms of embodiments, and the protection scope of the present application is not limited to the embodiments mentioned in the text. The drawings and the description in the text are essentially illustrative rather than limiting the present application. In the drawings, the same components are denoted by the same reference numerals, and the components having similar structures or functions are denoted by similar reference numerals.

[0027] As shown in Figs. 1-4 , a preferred embodiment of the present application provides a double eccentric ball valve, which comprises a valve body 1, the valve body 1 is respectively provided with a fluid medium inlet a and an outlet b, and a valve seat 2 is arranged at the inlet a and the outlet b; the inner cavity of the valve body 1 is provided with two hemispherical sealing elements 3, 4, the two hemispherical sealing elements 3, 4 are connected to form a whole, and the centers of the two hemispheres are apart by a set distance R; the upper surface and the lower surface of the inner cavity of the valve body 1 are respectively designed with two pairs of valve rod shaft holes 6 (7), 8 (9), and the two pairs of shaft holes 6 (7), 8 (9) are arranged on the center lines of the two hemispheres. The two pairs of center lines of the two hemispherical sealing elements 3, 4 in the x-axis and y-axis directions in the xy plane are apart by a certain distance.

[0028] Valve body 1, circular, straight through, each of the two through holes is designed with device valve seat 2, sealing ring 5 step and threaded hole; in the valve body 1 cavity lower wall and pipeline centerline as a reference, each offset 3-15mm in opposite directions are designed with valve stem shaft hole 8, 9, the lower end of the shaft hole 8, 9 is designed with gasket step bottom cover combined threaded hole; the upper wall of the valve body 1 inner cavity is designed with valve stem shaft hole 6, 7 which is symmetrical and concentric with the lower wall, the upper end of the shaft hole 6, 7 is designed with a step to prevent the blowout gasket 10 and a packing cavity 11, the upper end of the packing hole 11 is designed with a packing gland 12 and a bolt hole connected with the bracket; the valve body 1 material can be selected according to the working condition medium WCB, CF8, CF3, etc.

[0029] Two hemispheres (seals) 3, 4; the hemispheres are U-shaped, about one third of a sphere cut, one side is designed with an SR spherical surface, the other side is designed with two hexagonal holes and two positioning screws combined with the upper and lower valve stems, the center of the hexagonal hole is offset 3-15mm from the center of the SR spherical surface, the eccentricity is matched with the eccentricity of the upper valve stem shaft hole of the valve body, the material of the two hemispheres can be selected according to the working condition WCB, CF8, CF3, etc., the SR spherical surface can be surfacing 13Cr, STL, and chemical plating chromium, nickel, spraying NI60, WC, etc. to improve the hardness.

[0030] Valve seat 2 is cylindrical, the inner diameter of valve seat 2 is equal to the nominal diameter of valve body 1; one end of valve seat 2 has a flange matched with the inner diameter size of the inlet and outlet of valve body 1, the flange is provided with a counterbore and a through hole combined with valve body 1, the other end of valve seat 2 is provided with a groove 13 for embedding a sealing ring; the groove is provided with a sealing ring 14 for sealing with the surface of hemisphere 3 (4).

[0031] Sealing ring 14 is circular, the end face is provided with an angle less than or equal to 45° matched with hemisphere spherical surface 3.

[0032] Valve seat 2, the material can be selected according to the working condition A105, F304, F316, etc., the valve seat 2 is like a disc, the inner diameter is designed with a circular hole equal to the diameter of the valve, the outer diameter is designed with a flange combined with the outlet inner cavity of the flow passage of valve body 1 and 4-24 counterbores and through holes for installing internal hexagonal screws, the other end is designed with a groove 13 for embedding a sealing ring.

[0033] The double eccentric ball valve further comprises upper and lower pairs of valve stems 15, 16, 17, 18, bottom cover 19, two gear plates 20 (22 not shown), driving device 21, lower valve stems 17, 18 one end matched with valve stem shaft hole 8 (9), the other end in contact with bottom cover 19; one end of upper valve stem 15, 16 matched with valve stem shaft hole 6, 7, the other end combined with gear plate 20 (22) and driving device 21.

[0034] Valve stem 15, 16, 17, 18, material can be selected according to the working condition 2Cr13, F304, F316, 17-4PH, etc., the valve stem is the power transmission part of the valve, divided into two upper and lower, the upper valve stem 15, 16 one end is designed with a six square head matched with the hemisphere, the other end of the upper part is designed with a device gear disc, the flat key groove of the driving device, the lower valve stem 17, 18 one end is designed with a six square head matched with the hemisphere, the other end is designed with a SR spherical surface in contact with the bottom cover.

[0035] Two pairs of valve stem shaft holes 6, 7 and 8, 9 are concentrically arranged six square holes aligned up and down; screw holes 31, 32 for tightening nails are arranged at the outer edge of the upper shaft hole 6, 7; steps for mounting gaskets and sealing rings and screw holes for mounting the bottom cover 13 are arranged at the outer edge of the lower shaft hole 8, 9.

[0036] The center lines of the two circles of the two hemispherical seals 3, 4 in the xy plane are 3mm apart in the x axis direction, and 15mm apart in the y axis direction.

[0037] Two gear discs 20 are designed on the two valve stems 15, 16 as power transmission, the modulus, tooth number and pressure angle of the two gear discs 20, 22 are equal and synchronous operation.

[0038] The gear material can be selected according to the need, such as cast iron, cast steel, carbon structural steel and alloy structural steel.

[0039] Further, it includes a track, the worm gear box 21 rotates the gear disc 20 on the first upper valve stem 15, and then drives the second upper valve stem 16 on the gear 22 on the second upper valve stem 16 through the track on the gear disc, the two hemispherical seals 3, 4 on the two valve stems 15, 16 rotate with the upper valve stems 15, 16 to open and close.

[0040] When the driving device (worm gear box) 21 rotates 90° clockwise, the two hemispheres 3, 4 in the inner cavity of the valve body 1 are in contact with and sealed by the sealing ring 14 at the same time, and when it rotates ≥90° clockwise, it has the effect of getting tighter and tighter, when it rotates 45° counterclockwise, the two hemispheres 3, 4 are opened by half, and when it rotates 90° counterclockwise, the two hemispheres 3, 4 are fully opened.

[0041] The application also provides another preferred embodiment, which is different from the above embodiment in that a taper matched with the spherical surface is designed at the contact between the valve seat 2 and the hemispherical seal 3, 4, and a hard sealing seat is formed by hard surfacing 13Cr, D507, STL, etc. on the taper surface. The hard sealing and the valve seat 2 are fixed by hard surfacing, and the material of the hard sealing is D507 or STL.

[0042] The double eccentric ball valve of the present application has the following features: one valve has two seals, and two eccentric shafts (valve stems) of different directions are designed on the axis of one pipeline. When the valve stems are driven to rotate axially, the two hemispheres rotate and reach opening or closing respectively. The working principle is that the seal is two hemispheres fixed in the inner cavity of the valve body with the valve stem, and a driving device is used to rotate the two valve stems to achieve opening and closing.

[0043] The double eccentric ball valve of the present application is researched and invented in view of the long-term leakage of the ball valve in the prior art and the lack of safety guarantee for the pipeline. It overcomes the valve seal leakage caused by many complex situations such as spring failure, long-term friction of the seal, expansion and contraction of the seal caused by high and low temperature difference, and can bear equal pressure in two directions. The seal has a double insurance effect and will be widely used in the fields of petroleum, chemical industry, natural gas, nuclear power, water supply system and the like.

[0044] The above is only the preferred embodiment of the present application. It should be noted that those skilled in the art can make some improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered within the protection scope of the present application.

Claims

1. A double eccentric ball valve, comprising a valve body, characterized in that, The valve body is provided with a fluid medium inlet and an outlet, and valve seats are provided at the inlet and outlet. The valve body cavity has two hemispherical seals connected together, with the centers of the two hemispheres spaced a predetermined distance apart. The valve body cavity has two pairs of valve stem shaft holes on its upper and lower surfaces, respectively, located on the center lines of the two hemispheres. The upper end of the valve stem shaft hole has a step for an anti-blowout gasket and a packing cavity. The upper end of the packing hole has bolt holes for connecting the packing gland and the support. The valve body includes two pairs of valve stems, a bottom cover, two gear discs, and a drive device. One end of the lower valve stem mates with the valve stem shaft hole, and the other end contacts the bottom cover. One end of the upper valve stem mates with the valve stem shaft hole, and the other end connects to the gear disc and the drive device. The two circles of the cross-section of the two hemispherical seals in the xy plane are... The centerlines of the x-axis and y-axis are 3-15mm apart, with the x-axis centerlines 3mm apart and the y-axis centerlines 15mm apart. The hemisphere is U-shaped, one-third of a sphere, with a spherical surface on one side and two hexagonal holes and two positioning screws on the other side for engaging with the upper and lower valve stems. The center of the hexagonal holes is offset from the center of the spherical surface by 3-15mm, and this eccentricity matches the eccentricity of the valve stem shaft hole on the valve body. When the drive device rotates 90° clockwise, the two hemispheres in the valve body cavity simultaneously contact and seal with the sealing ring. Further clockwise rotation of ≥90° results in a tighter sealing effect. When rotated 45° counterclockwise, each hemisphere opens halfway, and when rotated 90° counterclockwise, both hemispheres are fully open. The sealing ring is annular, with its end face having an angle of less than or equal to 45° to engage with the spherical surface of the hemisphere.

2. The double eccentric ball valve as described in claim 1, characterized in that, The valve seat is cylindrical, and its inner diameter is equal to the nominal diameter of the valve body. One end of the valve seat has a flange that matches the inner diameter of the valve body's inlet and outlet. The flange has a countersunk hole and a through hole for engaging with the valve body. The other end of the valve seat has a groove for fitting a sealing ring. A sealing ring for sealing the surface of the hemisphere is installed in the groove.

3. The double eccentric ball valve as described in claim 1, characterized in that, The valve seat is cylindrical, and its inner diameter is equal to the nominal diameter of the valve body. One end of the valve seat has a flange that matches the inner diameter of the valve body's inlet and outlet. The flange has a countersunk hole and a through hole for engaging with the valve body. The other end of the valve seat has a hard seal that matches the spherical surface of the hemisphere. The contact surface between the hard seal and the spherical surface is an inclined surface with an angle of less than or equal to 45°.

4. The double eccentric ball valve as described in claim 3, characterized in that, The hard seal is fixed to the valve seat by welding, and the material of the hard seal is D507 or STL.

5. The double eccentric ball valve as described in claim 1, characterized in that, The two pairs of valve stem shaft holes are aligned vertically and arranged concentrically; a step for installing gaskets and sealing rings and screw holes for installing the bottom cover are provided at the outer edge of the lower shaft hole.

6. The double eccentric ball valve as described in claim 1, characterized in that, The two gear discs are designed on two valve stems for power transmission. The two gear discs have the same module, number of teeth, pressure angle, and operate synchronously.

7. The double eccentric ball valve as described in claim 1, characterized in that, Including tracks, the drive device rotates the gear disk on the first upper valve stem, and then drives the gear disk on the second upper valve stem to rotate the second upper valve stem through the tracks on the gear disk. The two hemispherical seals on the first and second upper valve stems open and close as the first and second upper valve stems rotate.

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