Sealing structure for flange soft sealing butterfly valve

Abstract

The utility model provides a kind of sealing structure for flange soft sealing butterfly valve, comprising: butterfly plate, its reverse surface is connected pressure ring through fastener, and the first gap for extruding main sealing ring is formed between butterfly plate and pressure ring;Fastener passes through pressure ring, the first gap in turn and is screwed into butterfly plate;Main sealing ring is set between butterfly plate and pressure ring, and the inner wall of main sealing ring is close to fastener setting, and the outer wall on it is set with the convex circle matched with the inner ring of valve seat;Its along radial direction, outer ring reverse surface and the boss of pressing plate are resisted, and pressing plate is detachably connected with valve body;The inner ring of valve seat is located in the inside of boss, and the recess matched with convex circle is set on the inner wall of inner ring;The big end of inner ring is set towards the front surface of butterfly plate and forms on the inner wall of outer ring of its valve seat, and the small end of inner ring is inclined to inside, and cavity is formed between inner ring and outer ring.The utility model improves reverse sealing pressure.

Description

Technical Field

[0001] This utility model belongs to the technical field of flange soft-seal butterfly valves, and particularly relates to a sealing structure for flange soft-seal butterfly valves. Background Technology

[0002] Conventional flanged soft-seal butterfly valves use T-shaped sealing rings; the valve seat is either the valve body itself or welded stainless steel, with a tapered side. The T-shaped sealing ring is placed in the groove of the butterfly plate and is pressed tightly by a pressure ring. The sealing ring and the valve seat form an interference fit to achieve the required sealing pressure, thus sealing the valve. The two protrusions of the T-shaped sealing ring are installed in the grooves of the butterfly plate and the pressure ring to prevent the sealing ring from falling off.

[0003] In this structure, under positive pressure, the sealing ring moves towards the smaller end of the valve seat, and the seal improves with increasing pressure. However, under reverse sealing, the sealing ring moves towards the larger end of the valve seat under pressure, reducing the interference fit between the sealing ring and the valve seat, and may even cause it to detach. Therefore, the reverse sealing pressure of a conventional flange soft-seal butterfly valve is only about 1 / 3 of the positive pressure, and may not even achieve a sealing effect. Summary of the Invention

[0004] The purpose of this utility model is to provide a sealing structure for a flange soft-seal butterfly valve, in which there is a seal between the pressure ring and the butterfly plate. During reverse sealing, the medium cannot enter between the pressure ring and the butterfly plate, allowing the pressure ring to be subjected to a large area pressure from the medium, thus increasing the reverse sealing pressure. The technical solution adopted is as follows: A sealing structure for a flange soft-seal butterfly valve includes: The butterfly plate 1 is connected to the pressure ring 3 on its reverse side by fasteners 6. A first gap is formed between the butterfly plate 1 and the pressure ring 3 to compress the main sealing ring 12. The fasteners 6 pass through the pressure ring 3 and the first gap in sequence and are screwed into the butterfly plate 1. The main sealing ring 12 is disposed between the butterfly plate 1 and the pressure ring 3. The inner wall of the main sealing ring 12 is disposed close to the fastener 6, and its outer wall is provided with a convex circle that mates with the inner ring of the valve seat 10. In the radial direction, the reverse side of the outer ring abuts against the boss of the pressure plate 8. The pressure plate 8 is detachably connected to the valve body 9. The valve seat 10 has an inner ring located inside the boss, and a groove that mates with the convex circle is formed on the inner wall of the inner ring; the large end of the inner ring faces the front of the butterfly plate 1 and is formed on the inner wall of the outer ring of the valve seat 10, the small end of the inner ring is inclined inward, and a cavity is formed between the inner ring and the outer ring; the outer ring can move along the axial direction. When the medium flows in from the reverse side of the butterfly plate 1 to form a reverse seal, the cavity connects to the channel formed by the boss of the pressure plate 8 and the pressure ring 3.

[0005] Preferably, a second gap is formed between the front side of the butterfly plate 1, the front side of the main sealing ring 12, and the inner ring of the valve seat 10; when the medium flows in from the front side of the butterfly plate 1 to form a positive sealing state, the second gap connects to the channel formed by the valve body 9. The reverse side of the main sealing ring 12 forms a third gap with the inner ring of the valve seat 10. In the reverse sealing state, the third gap connects the channel formed by the boss of the pressure plate 8 and the pressure ring 3.

[0006] Preferably, the main sealing ring 12 includes a first inclined surface and a second inclined surface; The first inclined surface and the inner ring of the butterfly plate 1 and valve seat 10 form the second gap; The second inclined surface and the inner ring of the valve seat 10 form the third gap.

[0007] Preferably, the width W1 of the first inclined plane is smaller than the width W2 of the second inclined plane.

[0008] Preferably, an installation groove is provided on the reverse side of the pressure ring 3, in which a second O-ring 5, a sealing plate 4, and a butterfly spring 7 are installed in sequence; the fastener 6 passes through the bolt hole on the pressure ring 3, the butterfly spring 7, the sealing plate 4, and the second O-ring 5 in sequence, and is threadedly engaged with the butterfly plate 1.

[0009] Preferably, a No. 3 O-ring 11 is provided between the valve seat 10 and the valve body 9, and a No. 1 O-ring 2 is provided between the pressure ring 3 and the butterfly plate 1.

[0010] Preferably, in the reverse sealing state, a fourth gap is formed between the front side of the outer ring and the valve body 9.

[0011] Preferably, the main sealing ring 12 is fitted with the groove on the butterfly plate 1 and the groove on the pressure ring 3.

[0012] Compared with the prior art, the advantages of this utility model are: 1. The reverse sealing pressure is increased and bidirectional sealing is achieved.

[0013] 2. The inner ring of the valve seat is an elastic body, thus reducing friction between the main sealing ring and the valve seat and extending the service life of the main sealing ring. Specifically, the outer ring of the valve seat is thicker, and since it contacts the valve body, it cannot deform and is rigid. The inner ring, on the other hand, consists of thin plates suspended on both sides, with one end connected to the outer ring at an angle, allowing it to deform under pressure and thus making it elastic. Attached Figure Description

[0014] Figure 1 A partial view of the sealing structure for a flanged soft-seal butterfly valve; Figure 2 Structural diagram of the main sealing ring; Figure 3 for Figure 1 A partial view; Figure 4 This is a schematic diagram of the installation of a No. 2 O-ring; Figure 5 This is a structural diagram of a flange soft-seal butterfly valve.

[0015] The components are: 1. Butterfly plate; 2. No. 1 O-ring; 3. Pressure ring; 4. Sealing plate; 5. No. 2 O-ring; 6. Socket head screw; 7. Disc spring; 8. Pressure plate; 9. Valve body; 10. Valve seat; 11. No. 3 O-ring; 12. Main sealing ring. Detailed Implementation

[0016] The sealing structure for the flange soft-seal butterfly valve of this utility model will be described in more detail below with reference to the schematic diagrams, which illustrate the preferred embodiments of this utility model. It should be understood that those skilled in the art can modify the utility model described herein while still achieving the advantageous effects of this utility model. Therefore, the following description should be understood as being of general knowledge to those skilled in the art and is not intended to limit this utility model.

[0017] like Figures 1-5 A sealing structure for a flange soft-seal butterfly valve, comprising: The butterfly plate 1 is connected to the valve stem 13 on its front side and the pressure ring 3 is connected to the pressure ring 3 on its back side by fasteners 6. A first gap is formed between the butterfly plate 1 and the pressure ring 3 to compress the main sealing ring 12. The fasteners 6 pass through the pressure ring 3 and the first gap in sequence and are screwed into the butterfly plate 1. The main sealing ring 12 is disposed between the butterfly plate 1 and the pressure ring 3, and the main sealing ring 12 is engaged with the groove on the butterfly plate 1 and the groove on the pressure ring 3.

[0018] The inner wall of the main sealing ring 12 is located close to the fastener 6, and a convex circle that mates with the inner ring of the valve seat 10 is provided on its outer wall; along the radial direction, the reverse side of the outer ring abuts against the boss of the pressure plate 8, and the pressure plate 8 is detachably connected to the valve body 9. The inner ring of the valve seat 10 is located inside the boss, and a groove that mates with the convex circle is opened on the inner wall of the inner ring; the large end of the inner ring is set facing the front of the butterfly plate 1 and is formed on the inner wall of the outer ring of the valve seat 10, and the small end of the inner ring is inclined inward, forming a cavity between the inner ring and the outer ring; when the medium flows in from the back of the butterfly plate 1 to form a reverse sealing state, the cavity connects the boss of the pressure plate 8 and the channel formed by the pressure ring 3.

[0019] The outer and inner rings of the valve seat 10 are machined from a single piece of stainless steel.

[0020] The valve seat 10 adopts a disc-shaped elastic design and can move left and right. It can deform under pressure. By appropriately increasing or decreasing the interference fit between the main sealing ring and the valve seat, the sealing effect can be achieved and the friction between the main sealing ring and the valve seat can be reduced.

[0021] A second gap is formed between the front of the butterfly plate 1, the front of the main sealing ring 12, and the inner ring of the valve seat 10; when the medium flows in from the front of the butterfly plate 1 to form a positive sealing state, the second gap connects to the channel enclosed by the valve body 9.

[0022] The reverse side of the main sealing ring 12 forms a third gap with the inner ring of the valve seat 10. In the reverse sealing state, the third gap connects the boss of the pressure plate 8 and the channel formed by the pressure ring 3.

[0023] like Figure 2 The main sealing ring 12 includes a first inclined surface (narrow inclined surface) and a second inclined surface (wide inclined surface). The first inclined plane and the inner ring of the butterfly plate 1 and valve seat 10 form the second gap; The second inclined plane and the inner ring of valve seat 10 form the third gap.

[0024] Among them, the width W1 of the first inclined surface is smaller than the width W2 of the second inclined surface. Compared with the forward sealing, the main sealing ring 12 needs to provide a larger deformation in the reverse sealing to form an interference fit with the inner ring of the valve seat 10. Therefore, the second inclined surface needs to have a larger contact area with the medium.

[0025] like Figure 2 As shown, width W1 refers to the distance between points a and b; width W2 refers to the distance between points c and d.

[0026] like Figure 4 An installation groove is made on the reverse side of the pressure ring 3, in which the second O-ring 5, the sealing plate 4 and the butterfly spring 7 are installed in sequence; the fastener 6 passes through the bolt hole on the pressure ring 3, the butterfly spring 7, the sealing plate 4 and the second O-ring 5 in sequence, and is threadedly engaged with the butterfly plate 1.

[0027] The fastener 6 is screwed into the threaded hole on the disc plate 1 through the bolt hole on the pressure ring 3. There is a No. 2 O-ring 5 between the fastener 6 and the pressure ring 3, which is pressed by the sealing plate 4 and the disc spring 7 to seal the hex socket screw 6 and the pressure ring 3.

[0028] A No. 3 O-ring 11 is installed between the valve seat 10 and the valve body 9, and a No. 1 O-ring 2 is installed between the pressure ring 3 and the butterfly plate 1.

[0029] The outer circle (outer ring) of valve seat 10 has an O-ring groove for installing O-ring 11, which forms a seal with valve body 9. The outer circle of the step of butterfly plate 1 has an O-ring groove for installing O-ring 2, which contacts the inner circle (inner wall) of pressure ring 3 to form a seal.

[0030] like Figure 1 The front of the outer ring forms a fourth gap with the valve body 9.

[0031] Working principle of the sealing structure for flange soft-seal butterfly valves: During initial installation, the sealing bevel of the valve seat 10 forms a certain interference fit with the two convex circles of the main sealing ring 12 to achieve initial sealing. See Figure 3 .

[0032] In this embodiment, the "inner" direction refers to the direction toward the axis of the butterfly plate 1.

[0033] The reverse sealing pressure is equal to the forward sealing pressure.

[0034] 1. When the valve is subjected to positive pressure, the position of valve seat 10 is as follows: Figure 1 As shown: (1) When the pressure is relatively small, set as F1, the disc-shaped sealing slope (inner ring) of valve seat 10 has not reached the deformation, the interference of the main sealing ring 12 and valve seat 10 increases, and the sealing effect is achieved.

[0035] Specifically: the butterfly plate 1 deflects by Y1. The inner ring of the valve seat 10 does not deform, the valve seat 10 remains stationary, and the main sealing ring 12 moves to the right, pressing against the inner ring of the valve seat 10.

[0036] Furthermore, because the inner ring of the valve seat 10 is inclined inward, the main sealing ring 12 presses the valve seat 10 to the lower right and upward, thus increasing the interference fit.

[0037] (2) When the pressure increases to F2, the sealing surface (inner ring) of the valve seat 10 deforms, and the movement of the main sealing ring 12 (axial displacement to the right) also increases at the same time. The interference remains unchanged, so that sealing is achieved without increasing the friction between the main sealing ring 12 and the valve seat 10.

[0038] Specifically, the pressure applied by the medium to the butterfly plate 1 causes the butterfly plate 1 to undergo a deflection deformation Y2, while the valve seat 10 remains stationary.

[0039] The main sealing ring 12 on the butterfly plate 1 undergoes axial displacement to the right as the butterfly plate 1 deflects, while the interference fit remains unchanged.

[0040] During the above process, the valve seat 10 is always in contact with the main sealing ring 12.

[0041] (3) When the pressure is extremely high, it is set to F3. The outer side (inner ring) of the disc-shaped inclined surface of the valve seat 10 contacts the boss A of the pressure plate 8 to prevent the inclined surface of the valve seat 10 from deforming too much and being damaged. The interference of the main sealing ring 12 and the valve seat 10 is increased to ensure that the seal does not leak under high pressure.

[0042] Specifically, when pressure F3 is applied, the butterfly plate 1 undergoes a deflection deformation Y3, at which point the inner ring deforms until it abuts against the boss of the pressure plate 8. Preferably, the inner wall of the inner ring remains inclined at this point.

[0043] However, due to pressure F3, the main sealing ring 12 remains in a state of compressing the valve seat 10, and the interference is increased relative to the pressure F2.

[0044] Furthermore, the deformation of the inner ring of the valve seat 10 can be restored when switching between the forward sealing state and the reverse sealing state.

[0045] II. When the valve is subjected to reverse pressure, the position of valve seat 10 is as follows: Figure 1 As shown: (1) When the pressure is low, the outer circle of the disc-shaped inclined surface of the valve seat 10 (the outer wall of the inner ring) is subjected to the medium pressure and deforms inward. The two changes keep the inclined surface of the valve seat 10 in contact with the main sealing ring 12 and a certain amount of interference, so as to achieve the sealing effect.

[0046] Specifically, the butterfly plate 1 has a large contact area with the medium, which causes the main sealing ring 12 to tend to move away from the valve seat 10.

[0047] Furthermore, as the medium flows sequentially into the channel formed by the pressure plate 8, the channel formed by the boss of the pressure plate 8 and the pressure ring 3, and the cavity of the valve seat 10, the medium squeezes the inner ring inward, causing the inner ring to undergo radial deformation inward, meaning that the valve seat 10 tends to move closer to the main sealing ring 12.

[0048] Thus, the two changes keep the inclined surface of the valve seat 10 in contact with the main sealing ring 12 and maintain a certain interference fit.

[0049] During the above process, the valve seat 10 is always in contact with the main sealing ring 12.

[0050] (2) When the pressure is large, the outer circle of the butterfly plate 1 (the circle where the main sealing ring 12 is installed) deforms unevenly. The deformation is small near the valve stem and large far from the valve stem. In the position with large deformation, the interference fit between the main sealing ring 12 and the valve seat 10 is reduced or even disengaged. Therefore, the sealing effect cannot be achieved by relying solely on the movement of the valve seat 10, and additional functions are required.

[0051] like Figure 5 As shown, "the location with large deformation" refers to the part located on the outer circle of the butterfly plate 1 that is not connected to the valve stem 13.

[0052] Figure 5 In the middle, there are two valve stems 13, both of which extend radially.

[0053] According to the existing technology: a valve stem 13, one end of which is rotatably connected to the valve body 9, and the other end is detachably connected to the valve seat 10.

[0054] Another valve stem has one end rotatably connected to the valve body 9 and radially positioned on the end cap of the valve body 9, and the other end detachably connected to the valve seat 10.

[0055] When the pressure is high, the butterfly plate 1 undergoes a deflection deformation Y4, and the valve seat 10 and the butterfly plate 1 move to the left until the valve seat 10 abuts against the boss of the valve body 9. During the above process, the valve seat 10 remains in contact with the main sealing ring 12.

[0056] The right side of the pressure ring 3 is subjected to medium pressure, and because the pressure ring 3 and the fastener 6 are in clearance fit, that is, the bolt holes on the pressure ring 3 for installing the fastener 6 are smooth holes.

[0057] Therefore, the pressure ring 3 undergoes an axial displacement to the left, reducing the first gap between the pressure ring 3 and the butterfly plate 1. The disc spring on the fastener 6 (hex socket screw) continues to provide clamping force, ensuring the seal of the second O-ring 5, preventing the medium from flowing between the pressure ring 3 and the butterfly plate 1, and ensuring that the pressure ring 3 is only subjected to lateral pressure on one side.

[0058] The medium compresses the pressure ring 3, causing it to shift axially to the left. This reduces the first gap between the pressure ring 3 and the butterfly plate 1, resulting in radial outward deformation of the main sealing ring 12. At this time, the long inclined surface (second inclined surface) of the main sealing ring 12 is also subjected to medium pressure. The reason why "the long inclined surface (second inclined surface) of the main sealing ring 12 is also subjected to medium pressure" is that the third gap formed by the main sealing ring 12 and the inner ring of the valve seat 10 connects the channel formed by the boss of the pressure plate 8 and the pressure ring 3.

[0059] Since the volume of the rubber remains constant, the deformation of the main sealing ring 12 expands towards the inclined surface (inner ring) of the valve seat 10, increasing the interference fit and achieving a sealing effect.

[0060] When switching from reverse sealing to forward sealing, adjust valve stem 13. During valve closing, the valve seat 10 is pushed back to its original position by butterfly plate 1. Figure 1 The location shown.

[0061] The above are merely preferred embodiments of this utility model and do not constitute any limitation on this utility model. Any equivalent substitutions or modifications made by those skilled in the art to the technical solutions and contents disclosed in this utility model without departing from the scope of the technical solutions of this utility model shall still fall within the protection scope of this utility model.

Claims

1. A sealing structure for a flange soft-seal butterfly valve, characterized in that, include: The butterfly plate (1) is connected to the pressure ring (3) on its reverse side by fasteners (6). A first gap is formed between the butterfly plate (1) and the pressure ring (3) for compressing the main sealing ring (12). The fasteners (6) pass through the pressure ring (3) and the first gap in sequence and are screwed into the butterfly plate (1). The main sealing ring (12) is located between the butterfly plate (1) and the pressure ring (3). The inner wall of the main sealing ring (12) is located close to the fastener (6), and its outer wall is provided with a convex circle that mates with the inner ring of the valve seat (10). In the radial direction, the reverse side of the outer ring of the valve seat (10) abuts against the boss of the pressure plate (8). The pressure plate (8) and the valve body (9) are detachably connected. The valve seat (10) has an inner ring located inside the boss, and a groove that mates with the convex circle is opened on the inner wall of the inner ring; the large end of the inner ring is set facing the front of the butterfly plate (1) and is formed on the inner wall of the outer ring of the valve seat (10), the small end of the inner ring is inclined inward, and a cavity is formed between the inner ring and the outer ring.

2. The sealing structure for a flange soft-seal butterfly valve according to claim 1, characterized in that, A second gap is formed between the front of the butterfly plate (1), the front of the main sealing ring (12), and the inner ring of the valve seat (10); when the medium flows in from the front of the butterfly plate (1) to form a positive sealing state, the second gap connects to the channel formed by the valve body (9). The reverse side of the main sealing ring (12) forms a third gap with the inner ring of the valve seat (10). In the reverse sealing state, the third gap connects the boss of the pressure plate (8) and the channel formed by the pressure ring (3).

3. The sealing structure for a flange soft-seal butterfly valve according to claim 2, characterized in that, The main sealing ring (12) includes a first inclined surface and a second inclined surface; The first inclined surface and the inner ring of the butterfly plate (1) and valve seat (10) form the second gap; The second inclined surface and the inner ring of the valve seat (10) form the third gap.

4. The sealing structure for a flange soft-seal butterfly valve according to claim 3, characterized in that, The width W1 of the first inclined plane is less than the width W2 of the second inclined plane.

5. The sealing structure for a flange soft-seal butterfly valve according to claim 1, characterized in that, An installation groove is provided on the reverse side of the pressure ring (3), in which a second O-ring (5), a sealing plate (4) and a butterfly spring (7) are installed in sequence; the fastener (6) passes through the bolt hole on the pressure ring (3), the butterfly spring (7), the sealing plate (4) and the second O-ring (5) in sequence, and is threadedly engaged with the butterfly plate (1).

6. The sealing structure for a flange soft-seal butterfly valve according to claim 1, characterized in that, A No. 3 O-ring (11) is provided between the valve seat (10) and the valve body (9), and a No. 1 O-ring (2) is provided between the pressure ring (3) and the butterfly plate (1).

7. The sealing structure for a flange soft-seal butterfly valve according to claim 1, characterized in that, In the reverse sealing state, a fourth gap is formed between the front of the outer ring and the valve body (9).

8. The sealing structure for a flange soft-seal butterfly valve according to claim 1, characterized in that, The main sealing ring (12) is fitted with the groove on the butterfly plate (1) and the groove on the pressure ring (3).

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