Knife gate valve with anti-separation sealing strip

Abstract

According to the technical scheme, the knife gate valve is characterized in that the knife gate valve comprises a valve body, the U-shaped sealing strip limited in the valve body, a gate plate capable of making contact with the sealing strip and a packing gland located above the valve body and used for pressing packing, and a sealing groove for containing the sealing strip is formed in the valve body; a packing groove for containing packing is formed in the upper end of the valve body, opposite buckling feet are arranged on the edge of an opening, located on the inner wall of the valve body, of the sealing groove, the two opposite side walls of the sealing groove comprise straight walls connected with the buckling feet and inclined walls connecting the straight walls and the groove bottom of the sealing groove together, and the distance between the two buckling feet is smaller than the distance between the two straight walls. The distance between the two inclined walls is gradually reduced in the direction away from the buckling foot, the outline defined by the two straight walls, the two inclined walls and the groove bottom of the sealing groove is matched with the outline of the sealing strip, and the problems that in the prior art, a sealing strip is prone to disengaging from the sealing groove, and the structural stability of the sealing strip is poor are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of gate valves, and more particularly to a knife gate valve with a sealing strip that can prevent separation. Background Art

[0002] Knife gate valve is the abbreviation of wafer-type flat gate valve. This type of valve is famous for its short structure length, light weight, easy installation and maintenance, and is used in many low-pressure pipeline transportation systems. The prior art usually uses a hard seal for the seal between the gate and the valve body, that is, the edge of the gate fits tightly against the inner wall of the valve body. After the edge of the gate touches the inner wall of the valve body for many times, the edge of the gate and the inner wall of the valve body are damaged, thereby affecting the sealing performance. A Chinese patent with application number 2006200479500 discloses a knife gate valve, which has a groove with a rectangular cross-section on the inner wall of the valve body and a sealing strip placed in the groove. The inner wall of the sealing strip is flush with the opening end of the groove. Although the problem of easy wear of the edge of the gate and the inner wall of the valve body is solved, there are still defects. Because the inner wall of the sealing strip is flush with the opening end of the groove, adhesion and traction are likely to occur in the process from close contact to separation between the gate and the sealing strip. The sealing strip will be deformed or fall out of the groove under the action of multiple tractions. Even when the temperature of the inner cavity of the valve body changes, the sealing strip will fail and fall out of the groove under the influence of heat or cold, which will cause the sealing performance to decrease, and even the knife gate valve cannot be completely closed. Utility Model Content

[0003] In view of the deficiencies in the prior art, the utility model aims to provide a knife gate valve which can prevent a sealing strip from escaping from a groove and has a stable sealing strip structure.

[0004] To achieve the above-mentioned purpose, the utility model provides the following technical scheme: a knife gate valve with a sealing strip preventing detachment, comprising a valve body, a U-shaped sealing strip limited in the valve body, a gate plate capable of contacting the sealing strip, and a packing gland located above the valve body and used for pressing the packing, wherein a sealing groove for accommodating the sealing strip is provided in the valve body, a packing groove for accommodating the packing is provided at the upper end of the valve body, and buckle feet facing each other are provided on the opening edge of the sealing groove located on the inner wall of the valve body, and two facing side walls of the sealing groove each include a straight wall connected to the buckle feet and an inclined wall connecting the straight wall to the bottom of the sealing groove, a distance between the two buckle feet is smaller than a distance between the two straight walls, and a distance between the two inclined walls gradually decreases in a direction away from the buckle feet, a contour surrounded by the two straight walls, the two inclined walls and the bottom of the sealing groove matches the contour of the sealing strip, and the sealing strip is limited in the sealing groove by the two buckle feet both contacting the inner wall of the sealing strip.

[0005] As a further improvement of the utility model, the surfaces of the two buckle feet facing each other are both beveled to form sliding-in surfaces, and the distance between the two sliding-in surfaces gradually decreases along the radial direction of the valve body.

[0006] As a further improvement of the utility model, a sealing portion is provided on the inner wall of the sealing strip, the sealing portion being located between the two buckle feet and protruding toward the inner cavity of the valve body.

[0007] As a further improvement of the utility model, two compact parts are arranged on the inner wall of the sealing strip, which are respectively in contact with the two buckle feet, and the width of the contact surface between the two buckle feet and the corresponding compact parts is greater than or equal to the width of the corresponding compact parts.

[0008] As a further improvement of the utility model, both ends of the sealing strip extend into the packing groove and contact with the packing gland.

[0009] As a further improvement of the utility model, it also includes two centering blocks arranged opposite to each other and located at a height between the filling groove and the inner cavity of the valve body, and the valve body is provided with two centering grooves for accommodating the two centering blocks respectively.

[0010] As a further improvement of the utility model, the two centering blocks are both annular, and the two centering grooves are both provided with centering shafts passing through the inner cavities of the corresponding centering blocks.

[0011] The beneficial effects of the utility model are as follows: the two buckle feet are in contact with the inner wall of the sealing strip so that the sealing strip is limited in the sealing groove. The design of the buckle feet for limiting the sealing strip makes up for the defect in the prior art that the sealing strip is easily dislodged from the sealing groove, and ensures the installation stability of the sealing strip in the sealing groove; the structure of the sealing groove and the sealing strip is changed in design compared with the prior art, which can achieve a change in the assembly steps, and makes up for the defect that a greater external driving force is required when the two half valve bodies are connected by bolts due to the sealing strip being too wide, resulting in excessive deformation and damage of the sealing strip, or the threaded surface of the connecting bolt is easily damaged, resulting in unstable connection. By changing the installation steps of the sealing strip, it is possible to conveniently know whether the size of the sealing strip matches the sealing groove, so that a suitable sealing strip can be replaced in time to be installed in the sealing groove, thereby improving the installation efficiency of the sealing strip, while reducing the damage of related parts and components, and indirectly saving the manufacturer's cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a three-dimensional structural schematic diagram of the utility model;

[0013] Figure 2 It is an exploded view of the utility model;

[0014] Figure 3 It is a three-dimensional diagram of the sealing strip in the utility model;

[0015] Figure 4 This is the front view of the valve body and the sealing strip in the utility model when they are matched;

[0016] Figure 5 for Figure 4 Half-section stereogram at AA in the middle.

[0017] Figure numerals: 1. valve body; 11. sealing groove; 12. packing groove; 13. buckle foot; 14. straight wall; 15. inclined wall; 16. sliding surface; 17. centering groove; 18. centering shaft; 2. sealing strip; 21. sealing part; 22. compact part; 3. gate; 4. packing gland; 5. centering block; 51. shaft groove. DETAILED DESCRIPTION

[0018] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments, wherein the same components are indicated by the same reference numerals.

[0019] Reference Figures 1 to 5 As shown, a knife gate valve with a sealing strip preventing separation in this embodiment comprises a valve body 1, a U-shaped sealing strip 2 limited in the valve body 1, a gate plate 3 capable of contacting the sealing strip 2, and a packing gland 4 located above the valve body 1 and used for pressing the packing, a sealing groove 11 for accommodating the sealing strip 2 is provided in the valve body 1, and a packing groove 12 for accommodating the packing is provided at the upper end of the valve body 1;

[0020] Based on the aforementioned prior art, the radial length of the sealing strip 2 along the valve body 1 is smaller than the radial height of the sealing groove 11 along the valve body 1, and buckle feet 13 are integrally formed at the positions where the two side walls of the sealing groove 11 are higher than the sealing strip 2. The two buckle feet 13 are arranged opposite to each other and flush with the inner wall of the flow channel of the valve body 1. The two side walls of the sealing groove 11 include a straight wall 14 connected to the buckle feet 13 and an inclined wall 15 connecting the straight wall 14 and the bottom of the sealing groove 11. The distance between the two buckle feet 13 is smaller than the distance between the two straight walls 14, and the distance between the two inclined walls 15 gradually decreases in the direction away from the buckle feet 13. The sealing strip 2 is processed along the inner cavity shape of the sealing groove 11 so that the contour surrounded by the two straight walls 14, the two inclined walls 15 and the bottom of the sealing groove 11 matches the contour of the sealing strip 2. The sealing strip 2 includes a straight portion accommodated between the two straight walls 14 and a tip portion located between the two inclined walls 15. The distance between the two buckle feet 13 is smaller than the distance between the two straight walls 14. The distance between the two inclined walls 15 gradually decreases in the direction away from the buckle feet 13. The distance is between the maximum distance and the minimum distance between the two inclined walls 15. There are two ways to assemble the sealing strip 2. First, the same as the prior art, before the valve body 1 is assembled from two half valve bodies, the sealing strip 2 is first placed in the sealing groove 11 of one of the half valve bodies, and then the other half valve body is covered on the former half valve body, and the two half valve bodies are fixedly connected by bolts, so that the sealing strip 2 is located in the sealing groove 11. Second, different from the prior art, the two half valve bodies are first connected together by bolts, and then the tip of the sealing strip 2 is aligned with the opening of the sealing groove 11 and the sealing strip 2 is pushed toward the sealing groove 11. The tip and the straight part of the sealing strip 2 slide relative to the buckle feet 13 successively and deform accordingly to enter the sealing groove 11 until the facing surfaces of the two buckle feet 13 are separated from the sealing strip 2, and the sealing strip 2 restores its elastic deformation and fits tightly against the inner wall of the sealing groove 11, and the two buckle feet 13 fit against the inner wall of the sealing strip 2.

[0021] The design of the buckle foot 13 for limiting the sealing strip 2 makes up for the defect in the prior art that the sealing strip 2 is easily dislodged from the sealing groove 11, and ensures the installation stability of the sealing strip 2 in the sealing groove 11; the design of changing the structure of the sealing groove 11 and the sealing strip 2 can achieve a change in the assembly steps compared to the prior art, and makes up for the defect that the sealing strip 2 is excessively wide, resulting in a greater external driving force when the two half valve bodies are connected by bolts, causing the sealing strip 2 to be damaged due to excessive deformation, or the threaded surface of the connecting bolt is easily damaged, resulting in unstable connection. By changing the installation steps of the sealing strip 2, it is possible to easily know whether the size of the sealing strip 2 matches the sealing groove 11, so that the appropriate sealing strip 2 can be replaced in time to be installed in the sealing groove 11, thereby improving the installation efficiency of the sealing strip 2, while reducing the damage of related parts and components, and indirectly saving the manufacturer's cost.

[0022] As a specific implementation method of the improvement, refer to Figure 5As shown, the facing surfaces of the two buckle feet 13 are beveled to form a sliding surface 16, and the distance between the two sliding surfaces 16 gradually decreases along the radial direction of the valve body 1. This design makes the elastic deformation of the sealing strip 2 when it slides relative to the sliding surface 16 tend to be alleviated, and at the same time can reduce the wear of the sealing strip 2, thereby extending the service life of the sealing strip.

[0023] As a specific implementation method of the improvement, refer to Figure 3 and Figure 5 As shown, a sealing portion 21 is provided on the inner wall of the sealing strip 2, which is located between the two buckle feet 13 and protrudes toward the inner cavity of the valve body 1. The surface of the sealing portion 21 protruding toward the inner side of the valve body 1 is an arc surface. Compared with the prior art design of directly fitting the gate plate 3 with the flat inner wall of the sealing strip 2, such a design can make the elastic deformation of the sealing portion 21 more timely when the gate plate 3 and the sealing portion 21 are fitted, thereby reducing the contact area between the gate plate 3 and the sealing strip 2 while ensuring the sealing performance, thereby reducing the friction between the gate plate 3 and the sealing strip 2 and reducing the required torque.

[0024] As a specific implementation of the improvement, since the inner wall of the sealing strip 2 is flat and the buckle foot 13 only applies pressure to the edge of the inner wall of the sealing strip 2, the inner wall of the sealing strip 2 at the edge of the buckle foot 13 is easily broken by the shear force, thereby accelerating the damage of the sealing strip 2. To solve the above-mentioned problem, refer to Figure 3 and Figure 5 As shown, two compact portions 22 are provided on the inner wall of the sealing strip 2, which are in contact with the two buckle feet 13 respectively. The width of the fitting surface between the two buckle feet 13 and the corresponding compact portions 22 is greater than or equal to the width of the corresponding compact portions 22. When the sealing portion 21 is processed, the two compact portions 22 are respectively located on both sides of the sealing portion 21 and are independent of the sealing portion 21. The compact portions 22 fit with the inner walls of the corresponding buckle feet 13 so that there is a distance between the inner wall of the sealing strip 2 and the buckle feet 13, thereby avoiding the buckle feet 13 from generating shear force on the inner wall of the sealing strip 2, ensuring the structural stability of the sealing strip 2 and extending the service life of the sealing strip 2.

[0025] As a specific implementation method of the improvement, refer to Figure 1 , Figure 2 and Figure 5As shown, both ends of the sealing strip 2 extend into the packing groove 12 and contact with the packing gland 4. After the packing is filled into the packing groove 12, the packing will exert pressure on the outer wall of the sealing strip 2 and become thinner. Then the sealing strip 2 extends in the length direction of the sealing strip 2, and the portion of the sealing strip 2 located in the sealing groove 11 is squeezed and becomes thicker by the end portion, thereby further improving the connection stability and sealing performance of the sealing strip 2 in the sealing groove 11, and avoiding the phenomenon that the medium flows out of the valve body 1 through the gap between the sealing groove 11 and the sealing strip 2; furthermore, with the loss of the packing, the packing in the packing groove 12 will become loose, and the end of the sealing strip 2 will become thicker again under the elastic action and squeeze the packing in the packing groove 12, so that the packing in the packing groove 12 becomes tight again, which can extend the sealing effect of the packing.

[0026] As a specific implementation method of the improvement, refer to Figure 5 As shown, when the valve body 1 is still two separated half-valve bodies, centering grooves 17 are opened on the facing surfaces of the two half-valve bodies, and the centering grooves 17 are located between the stuffing groove 12 and the inner cavity of the half-valve body for medium flow. A centering block 5 is installed in each of the two centering grooves 17, and the two centering blocks 5 can fit with the two end surfaces of the gate plate 3 respectively. Such a design can assist and calibrate the position of the gate plate 3 relative to the valve body 1, ensure that the gate plate 3 keeps moving straight, and facilitate the opening and closing of the gate plate 3.

[0027] As a specific implementation method of the improvement, refer to Figure 5 As shown, the two centering blocks 5 are designed to be disc-shaped and have an axial groove 51 in the middle. The inner cavity contours of the two centering grooves 17 are circular, and a centering shaft 18 with a height less than that of the centering groove 17 is integrally formed in the center of the two centering grooves 17. The centering block 5 is sleeved on the centering shaft 18, and the axial groove 51 and the centering shaft 18 are plugged together, and the centering block 5 is installed in place in the centering groove 17. Such a design can improve the coaxiality of the two centering blocks 5, thereby avoiding the phenomenon of height difference between the two centering blocks 5 and ensuring that the force positions on both sides of the gate plate 3 are the same.

[0028] The above is only a preferred embodiment of the present invention. The protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A knife gate valve with a sealing strip preventing separation, comprising a valve body (1), a U-shaped sealing strip (2) limited in the valve body (1), a gate plate (3) capable of contacting the sealing strip (2), and a packing gland (4) located above the valve body (1) and used to press the packing, wherein a sealing groove (11) for accommodating the sealing strip (2) is provided in the valve body (1), and a packing groove (12) for accommodating the packing is provided at the upper end of the valve body (1), characterized in that: The opening edge of the sealing groove (11) located on the inner wall of the valve body (1) is provided with buckle feet (13) facing each other. The two facing side walls of the sealing groove (11) each include a straight wall (14) connected to the buckle feet (13) and an inclined wall (15) connecting the straight wall (14) and the bottom of the sealing groove (11). The distance between the two buckle feet (13) is smaller than the distance between the two straight walls (14). The distance between the two inclined walls (15) gradually decreases in the direction away from the buckle feet (13). The contour enclosed by the two straight walls (14), the two inclined walls (15) and the bottom of the sealing groove (11) matches the contour of the sealing strip (2). The sealing strip (2) is limited in the sealing groove (11) by the two buckle feet (13) contacting the inner wall of the sealing strip (2).

2. A knife gate valve with a sealing strip that prevents separation according to claim 1, characterized in that: The surfaces of the two buckle feet (13) facing each other are both beveled to form a sliding surface (16), and the distance between the two sliding surfaces (16) gradually decreases along the radial direction of the valve body (1).

3. A knife gate valve with a sealing strip that prevents separation according to claim 1 or 2, characterized in that: The inner wall of the sealing strip (2) is provided with a sealing portion (21) located between the two buckle feet (13) and protruding toward the inner cavity of the valve body (1).

4. A knife gate valve with a sealing strip that prevents separation according to claim 1 or 2, characterized in that: The inner wall of the sealing strip (2) is provided with two compact parts (22) which respectively contact with the two buckle feet (13), and the width of the contact surface between the two buckle feet (13) and the corresponding compact parts (22) is greater than or equal to the width of the corresponding compact parts (22).

5. A knife gate valve with a sealing strip that prevents separation according to claim 1 or 2, characterized in that: Both ends of the sealing strip (2) extend into the packing groove (12) and contact the packing gland (4).

6. A knife gate valve with a sealing strip that prevents separation according to claim 1 or 2, characterized in that: It also includes two centering blocks (5) arranged opposite to each other and located at a height between the filling groove (12) and the inner cavity of the valve body (1), and the valve body (1) is provided with two centering grooves (17) for accommodating the two centering blocks (5) respectively.

7. A knife gate valve with a sealing strip that prevents separation according to claim 6, characterized in that: The two centering blocks (5) are both disc-shaped and have an axis groove (51) at the center. The two centering grooves (17) are both provided with a centering shaft (18) that can be inserted into the axis groove (51).

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