Double-seal butterfly valve

Abstract

The utility model relates to a double-seal butterfly valve, which comprises a valve body, a valve seat, a butterfly plate, a valve rod and a transmission mechanism, a sealing surface of the butterfly plate is matched with a sealing surface of the valve seat to form a conical sealing pair, and the valve seat is fixedly arranged on a radial inner step of a valve body channel through a compression ring; the valve seat is characterized in that the valve seat is of an elastic double-valve-seat structure composed of a main sealing seat of a bidirectional elastic soft sealing seat and an auxiliary sealing seat of a bidirectional elastic hard sealing seat. In the forward working state, forward medium pressure pushes the butterfly plate sealing face to be in pressing fit with the main sealing seat and the auxiliary sealing seat at the same time to form a double-sealing-pair structure. In a reverse working state, reverse medium pressure pushes the lip-shaped sealing ring and the stainless steel sealing ring to deform towards the butterfly plate, and the lip-shaped sealing ring and the stainless steel sealing ring are in pressing fit with the sealing surface of the butterfly plate to form a double-sealing pair structure; when the lip-shaped sealing ring of the main sealing seat is burnt out due to a high-temperature accident, the stainless steel sealing ring of the auxiliary sealing seat and the sealing surface of the butterfly plate form a hard sealing structure. The fireproof door has the advantages of good fireproof performance, reliable bidirectional sealing performance and the like.

Description

Technical Field

[0001] The utility model belongs to the field of valves, and particularly relates to a double-sealed butterfly valve. Background Art

[0002] The sealing pair of a traditional two-way sealed butterfly valve generally consists of a metal and a non-metal / graphite sealing pair. When the non-metal / graphite is worn and leaks, the sealing performance of the metal sealing pair is very poor, and it cannot even seal, lacking a true double-sealing function. Especially in petrochemical and chemical flammable and corrosive media, the traditional sealing ring is integrally formed by rolling polytetrafluoroethylene and stainless steel. The sealing relies on forced sealing of the polytetrafluoroethylene. Once the polytetrafluoroethylene is damaged, the stainless steel cannot seal reliably, resulting in leakage. For example, the double-sealed butterfly valve with the patent number CN200720109884.X includes a valve body, a valve seat, a valve stem, a butterfly plate, and a transmission mechanism. The valve seat sealing surface consists of a metal valve seat sealing surface and a non-metal valve seat sealing surface to form a double-valve seat sealing surface structure. When the valve is closed, first, the non-metal valve seat sealing surface contacts and cooperates with the butterfly plate sealing surface for sealing. As the pressure increases, the non-metal valve seat sealing surface is squeezed by the butterfly plate sealing surface, so that the butterfly plate sealing surface cooperates with both the metal valve seat sealing surface and the non-metal valve seat sealing surface for sealing, forming a double-sealing structure. The main disadvantages of the prior art are: during frequent opening and closing processes, the non-metal valve seat sealing ring is very easy to lose plasticity after being compressed or aged, losing its sealing performance. The metal valve seat sealing ring and the butterfly plate sealing surface are in a hard-to-hard contact, with very poor sealing performance, even leading to leakage, and it cannot be applied to high-temperature and two-way medium working conditions. Summary of the Invention

[0003] Aiming at the shortcomings of the prior art, the utility model develops a double-sealed butterfly valve with a double elastic sealing function of the valve seat, forming an elastic automatic compensation sealing pair with the butterfly plate sealing surface, realizing two-way sealing, fire prevention, and reliable sealing performance.

[0004] The technical solution of the utility model is as follows:

[0005] A double-sealed butterfly valve includes a valve body, a valve seat, a butterfly plate, a valve stem, and a transmission mechanism. The butterfly plate is fixedly installed on the valve stem by a pin shaft and is placed in the valve body channel. The butterfly plate sealing surface and the valve seat sealing surface cooperate with each other to form a conical sealing pair. The valve seat is fixedly installed on the radial inner step of the valve body channel by a compression ring; the feature is that: the valve seat consists of a main sealing seat and a sub-sealing seat to form an elastic double-valve seat structure; the main sealing seat uses a lip-shaped sealing ring and is fixedly installed on the radial inner step of the valve body channel by a compression ring to form a two-way elastic soft sealing seat, and the sub-sealing seat uses a stainless steel sealing ring and is press-fitted between the lip-shaped sealing ring and the radial inner step of the valve body channel to form a two-way elastic hard sealing seat.

[0006] In the above technical solution, a cylindrical step is provided on the back of the lip seal ring, and an annular inner shoulder is provided on the inner wall of the first inner hole of the pressure ring. The annular inner shoulder abuts against the middle part of the outer cylindrical surface of the cylindrical step, and the outer cylindrical surface of the lip seal ring is tightly fitted with the inner wall of the second inner hole of the pressure ring; an annular groove is provided in the annular plane between the cylindrical step of the lip seal ring and the outer cylindrical surface of the lip seal ring, and an axial annular shoulder extending along the inner wall of the first inner hole is provided in the right-side plane of the pressure ring, and the axial annular shoulder is fitted into the annular groove; a U-shaped groove is provided on the left side of the stainless steel seal ring, and the U-shaped groove is pressed on the radial inner step of the valve body through the annular boss on the right side of the lip seal ring. The right end of the inner side of the stainless steel seal ring is provided with a conical sealing surface that cooperates with the butterfly plate.

[0007] In the above technical solution, an annular groove with a V-shaped cross-section is provided on the outer side of the sealing surface of the lip seal ring, and a cavity is formed between the annular groove and the left-side back surface of the conical sealing surface of the stainless steel seal ring.

[0008] In the above technical solution, an upper bearing device is provided at the upper end of the valve stem, and a lower bearing device is provided at the lower end. The upper bearing device is connected to the valve body through an upper bracket, and the lower bearing device is connected to the valve body through a lower bracket. Heat insulation cavities are respectively provided between the upper bearing device and the lower bearing device and the valve body.

[0009] In the above technical solution, dust-proof devices are respectively provided between the valve stem and the upper bearing device and the lower bearing device.

[0010] In the above technical solution, a composite sealing device composed of a packing sealing device and a grease injection sealing device is provided between the valve stem and the lower end of the valve body.

[0011] The beneficial effects of the present utility model compared with the prior art are as follows: The valve seat is composed of a main sealing seat of a double-way elastic soft sealing seat and a sub-sealing seat of a double-way elastic hard sealing seat to form an elastic double-valve seat structure. In the forward working state, the forward medium pressure pushes the sealing surface of the butterfly plate to be tightly fitted with both the main sealing seat and the sub-sealing seat to form a double-sealing pair structure; in the reverse working state, the reverse medium pressure pushes the lip seal ring and the stainless steel seal ring to deform towards the butterfly plate and be tightly fitted with the sealing surface of the butterfly plate to form a double-sealing pair structure; when a high-temperature accident occurs and the lip seal ring of the main sealing seat is burned out, the stainless steel seal ring of the sub-sealing seat and the sealing surface of the butterfly plate form a hard-sealing structure. It has the advantages of good fireproof performance and reliable double-way sealing performance. Description of the Drawings

[0012] Figure 1 is a structural cross-sectional view of the present utility model.

[0013] Figure 2 is the present utility model Figure 1 The enlarged view of the partial structure at A in it.

[0014] Figure 3 is a partial enlarged view of the structure at position B in the present utility model Figure 1 in the present utility model

[0015] In the figure: 1 lower bearing, 2 dust-proof graphite ring, 3 lower packing gland, 4 grease injection ring, 5 valve body, 6 compression ring, 7 butterfly plate, 8 pin shaft, 9 lip seal, 10 stainless steel sealing ring, 11 packing, 12 dust-proof graphite, 13 upper bearing, 14 transmission mechanism, 15 cylindrical step, 16 annular inner shoulder, 17 first inner hole, 18 second inner hole, 19 axial annular shoulder, 20 annular boss, 21 annular groove, 22 valve stem Specific embodiments

[0016] As Figure 1 shown in the double-sealed butterfly valve, which includes a valve body 5, a valve seat, a butterfly plate 7, a valve stem 22, and a transmission mechanism 14. The butterfly plate 7 is fixedly installed on the valve stem 22 by a pin shaft 8 and is placed in the channel of the valve body 5. The sealing surface of the butterfly plate 7 and the sealing surface of the valve seat cooperate with each other to form a conical sealing pair. The butterfly plate 7 adopts a truss streamline structure design to reduce flow resistance, noise, and flow loss. The truss streamline structure means that a hollow structure is adopted in the middle of the two end planes of the butterfly plate 7 to reduce the flow resistance after the butterfly plate 7 is opened. The valve seat is fixedly installed on the radial inner step of the channel of the valve body 5 by a compression ring 6. Its characteristics are: the valve seat consists of a main sealing seat and a secondary sealing seat to form an elastic double-valve seat structure; the main sealing seat adopts a lip seal 9 to be fixedly installed on the radial inner step of the channel of the valve body 5 by a compression ring 6 to form a two-way elastic soft sealing seat, and the secondary sealing seat adopts a stainless steel sealing ring 10 to be press-fitted between the lip seal 9 and the radial inner step of the channel of the valve body 5 to form a two-way elastic hard sealing seat. The sealing surface of the lip seal 9 and the sealing surface of the butterfly plate 7 cooperate with each other to form a soft sealing pair with a two-way pressing and sealing function, and the sealing surface of the stainless steel sealing ring 10 and the sealing surface of the butterfly plate 7 cooperate with each other to form a hard sealing pair with a two-way elastic pressing and sealing function. When the soft sealing pair is burned out at high temperature, the hard sealing pair undertakes the sealing function to prevent the medium from leaking, and has reliable fire prevention performance and sealing performance

[0017] As Figure 2As shown, a cylindrical step 15 is provided on the back surface of the lip seal 9. The cylindrical step 15 is the outer cylindrical surface of a cylinder protruding leftward from the lip seal 9. The sealing surface of the lip seal 9 is arranged on the inner hole wall at the left end of the cylindrical step 15. An annular inner shoulder 16 is provided on the inner wall of the first inner hole 17 of the pressure ring 6. The annular inner shoulder 16 abuts against the middle part of the outer cylindrical surface of the cylindrical step 15, so that the cylindrical step 15 radially presses tightly with the contact point as the fulcrum to form a two-way elastic soft seal pair with the sealing surface of the butterfly plate 7. There is an annular plane between the inner hole of the pressure ring 6 and the first inner hole 17. There is a gap between this annular plane and the left end face of the lip seal 9, so that the reverse medium can enter this gap to push the sealing surface of the lip seal 9 to press tightly against the sealing surface of the butterfly plate 7 for sealing. The outer cylindrical surface of the lip seal 9 is tightly fitted with the inner wall of the second inner hole 18 of the pressure ring 6 to limit the radial movement of the lip seal 9; an annular groove is provided in the annular plane between the cylindrical step 15 of the lip seal 9 and the outer cylindrical surface of the lip seal 9. An axial annular shoulder 19 extending along the inner wall of the first inner hole 17 is provided in the right side plane of the pressure ring 6. This axial annular shoulder 19 is press-fitted into the annular groove of the lip seal 9 to improve the fixed installation performance of the lip seal 9 between the pressure ring 6 and the valve body 5; a U-shaped groove is provided on the left side of the stainless steel seal ring 10. This U-shaped groove is press-fitted on the radial inner step of the valve body 5 through the annular boss 20 on the right side of the lip seal 9, so that the inner side of the U-shaped groove of the stainless steel seal ring 10 has strong elasticity. The right end of the inner side of the stainless steel seal ring 10 is provided with a conical sealing surface that cooperates with the butterfly plate 7.

[0018] An annular groove 21 with a V-shaped cross-section is provided on the outer side of the sealing surface of the lip seal 9. A cavity is formed between the annular groove 21 and the back surface of the conical sealing surface of the stainless steel seal ring 10, providing an elastic deformation space for one side of the sealing surface of the stainless steel seal ring 10, as Figure 2 shown.

[0019] An upper bearing device is provided at the upper end of the valve stem 22, and a lower bearing device is provided at the lower end. The upper bearing device is connected to the valve body 5 through an upper bracket, and the lower bearing device is connected to the valve body 5 through a lower bracket, reducing the rotation torque of the valve stem 22. Insulation cavities are respectively provided between the upper bearing device and the lower bearing device and the valve body 5 to isolate the influence of the medium temperature in the inner cavity of the valve body 5 on the working performance of the upper bearing device and the lower bearing device. The upper bearing device is composed of an upper bearing 13 installed between the upper bracket and the valve stem 22 through an upper gland. The lower bearing device is composed of a lower bearing 1 installed between the lower bracket and the valve stem 22 through a lower gland, as Figure 1 、 Figure 3 shown.

[0020] Dust-proof devices are respectively provided between the valve stem 22 and the upper bearing device and the lower bearing device. The dust-proof devices are composed of a dust-proof graphite 12 provided between the outer cylindrical surface of the valve stem 22 and the upper bracket and a dust-proof graphite ring 2 provided between the lower brackets, asFigure 1 , Figure 3 as shown

[0021] A composite sealing device composed of a packing sealing device and a grease injection sealing device is provided between the valve stem 22 and the lower end of the valve body 5. The packing sealing device is composed of installing a lower packing in the stuffing box on the valve stem 22 and the valve body 5, and the lower packing is pressed and installed in the stuffing box by a lower packing gland 3; the grease injection sealing device is composed of arranging a grease injection ring 4 in the middle of the lower packing. As Figure 1 shown, a packing 11 is provided between the valve stem 22 and the upper end of the valve body 5.

Claims

1. A double-sealed butterfly valve, comprising a valve body (5), a valve seat, a butterfly plate (7), a valve stem (22), and a transmission mechanism (14). The butterfly plate (7) is fixedly installed on the valve stem (22) by a pin shaft (8) and is placed in the channel of the valve body (5). The sealing surface of the butterfly plate (7) and the sealing surface of the valve seat cooperate with each other to form a conical sealing pair. The valve seat is fixedly installed on the radial inner step of the channel of the valve body (5) by a compression ring (6); characterized in that: The valve seat is composed of a main seal seat and a secondary seal seat to form an elastic double-valve seat structure; the main seal seat uses a lip seal ring (9) fixed and installed on the radial inner step in the passage of the valve body (5) through a pressing ring (6) to form a double-direction elastic soft seal seat, and the secondary seal seat uses a stainless steel seal ring (10) press-fitted between the lip seal ring (9) and the radial inner step of the passage of the valve body (5) to form a double-direction elastic hard seal seat.

2. The double-sealed butterfly valve according to claim 1, characterized in that: A cylindrical step (15) is provided on the back of the lip seal ring (9), and an annular inner shoulder (16) is provided on the inner wall of the first inner hole (17) of the pressing ring (6). The annular inner shoulder (16) abuts against the middle of the outer cylindrical surface of the cylindrical step (15), and the outer circular surface of the lip seal ring (9) is in tight fit with the inner wall of the second inner hole (18) of the pressing ring (6); an annular groove is provided in the annular plane between the cylindrical step (15) of the lip seal ring (9) and the outer circular surface of the lip seal ring (9), and an axial annular shoulder (19) extending along the inner wall of the first inner hole (17) is provided in the right-side plane of the pressing ring (6), and this axial annular shoulder (19) is press-fitted into the annular groove of the lip seal ring (9); a U-shaped groove is provided on the left side of the stainless steel seal ring (10), and this U-shaped groove is press-fitted on the radial inner step of the valve body (5) through the annular boss (20) on the right side of the lip seal ring (9), and a conical sealing surface for cooperating with the butterfly plate (7) is provided at the right end of the inner side of the stainless steel seal ring (10).

3. The double-sealed butterfly valve according to claim 2, characterized in that: at An annular groove (21) with a V-shaped cross-section is provided on the outer side of the sealing surface of the lip seal ring (9), and a cavity is formed between this annular groove (21) and the back of the conical sealing surface of the stainless steel seal ring (10).

4. The double-sealed butterfly valve according to claim 1 or 2 or 3, characterized in that: An upper bearing device is provided at the upper end of the valve stem (22), and a lower bearing device is provided at the lower end. The upper bearing device is connected to the valve body (5) through an upper bracket, and the lower bearing device is connected to the valve body (5) through a lower bracket. Heat insulation cavities are respectively provided between the upper bearing device and the lower bearing device and the valve body (5).

5. The double-sealed butterfly valve according to claim 4, characterized in that: Dust-proof devices are respectively provided between the valve stem (22) and the upper bearing device and the lower bearing device.

6. The double-sealed butterfly valve according to claim 5, wherein: A composite sealing device composed of a packing sealing device and a grease injection sealing device is provided between the valve stem (22) and the lower end of the valve body (5).

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