Bilateral opening and closing railway tank car unloading valve

Abstract

The invention relates to a unloading valve, in particular to a bilateral opening and closing railway tank car unloading valve, and aims to overcome the defects that in the prior art, a valve seat of an unloading valve is prone to being damaged to cause leakage, and the connecting position of a valve body and a valve deck is not tightly matched in a sealing mode to cause leakage. The inner side wall of the bilateral opening and closing railway tank car unloading valve is matched with the outer side wall of the corresponding position of the valve element, the first boss and the second boss are arranged on the inner side wall in the circumferential direction and abut against the valve element to form two seals, the two valve seats are equivalently provided with four seals, a certain pre-tightening force can be generated after assembling, and the sealing effect is good. The valve seat has a certain compensation effect after being abraded, and the sealing performance of the unloading valve is improved.

Description

Technical Field

[0001] The present invention relates to a bottom discharge valve, and more particularly to a double-sided switch bottom discharge valve for railway tank cars. Background Art

[0002] Some railway tank cars adopt the method of discharging oil from the bottom of the tank body. For example, sticky oil tank cars for transporting crude oil all adopt bottom discharge valves with switches on both sides of the car body. During the investigation of the application and maintenance of the bottom discharge valves of sticky oil tank cars, it is found that there are some problems with the bottom discharge valves. First, there is leakage at the valve seat of the bottom discharge valve. Second, there is leakage at the connection part between the valve body and the valve cover. Third, the 4 fastening studs of the connecting flange in the middle of the valve are difficult to disassemble during maintenance, resulting in low maintenance efficiency.

[0003] The main reasons for the above problems are as follows: First, sticky oil tank cars transport crude oil, and the medium contains a lot of impurities and foreign objects such as stones. Even some non-standard operators open the manhole, resulting in the entry of lead seals and iron wires into the tank. When discharging oil, foreign objects will enter the bottom discharge valve, causing damage to the non-metallic valve seat when the valve is opened and closed. In addition, the non-metallic valve seat of the bottom discharge valve is made of polytetrafluoroethylene material, which has poor wear resistance. After the valve is opened and closed a certain number of times, the raised lip of the valve seat wears, resulting in damage and scratches on the valve seat, and even leakage of the valve in severe cases. Second, the bottom discharge valve is a two-piece structure. Due to wear, deformation or other factors during operation and maintenance, the sealing fit at the connection position between the valve body and the valve cover is not tight, resulting in leakage. Third, the 4 fastening studs of the valve body and the valve cover of the bottom discharge valve are inconvenient to disassemble due to space limitations, affecting the maintenance efficiency. Summary of the Invention

[0004] The purpose of the present invention is to solve the deficiencies in the prior art that the valve seat of the bottom discharge valve is easily damaged resulting in leakage, and the sealing fit at the connection position between the valve body and the valve cover is not tight resulting in leakage, and to provide a double-sided switch bottom discharge valve for railway tank cars.

[0005] To achieve the above purpose, the technical solution provided by the present invention is as follows:

[0006] The present invention provides a double-sided switch bottom discharge valve for railway tank cars, including a valve body, an opening and closing block, an opening and closing shaft, a spherical valve core, a valve cover, and two valve seats. The valve body and the valve cover are coaxially connected and communicate with each other. A spherical accommodation cavity is provided in the valve body for setting the valve core. One end of the opening and closing shaft passes through the side wall of the valve body and is connected to the valve core. The characteristics are that: the two valve seats are respectively located at the inlet and outlet positions of the valve body to seal the outer side of the valve core; the valve seat is a ring structure, the outer side wall abuts against the valve body or the valve cover, the inner side wall is adapted to the outer side wall at the corresponding position of the valve core, and a first convex platform and a second convex platform are arranged along the circumferential direction on the inner side wall. Both the first convex platform and the second convex platform abut against the valve core to form two seals.

[0007] Further, a first chamfer is provided at positions on the inner side wall of the valve seat close to the inlet and outlet of the valve body; a second chamfer is provided at positions on the outer side wall of the valve seat away from the inlet and outlet of the valve body.

[0008] Further, both the first boss and the second boss are arc-shaped bosses, and the height from the highest point to the inner side wall of the valve seat is 0.8 - 1.0 mm;

[0009] The ratio of the circumferential width L1 of the inner side wall corresponding to the first boss, the circumferential width L2 of the inner side wall between the first boss and the second boss, and the circumferential width L3 of the inner side wall corresponding to the second boss is: 1:1:1.

[0010] Further, one end of the valve cover is inserted into the outlet of the valve body, and a first flange is provided circumferentially near the end. A valve body flange is correspondingly provided at the outlet end of the valve body. The first flange and the valve body flange are connected by studs, so that the valve cover is connected to the valve body;

[0011] A second flange is provided at the other end of the valve cover for connecting to an external structure, and notches are provided at positions of the second flange corresponding to the studs.

[0012] Further, a flat gasket is provided between the radial contact surfaces of the first flange and the valve body flange, and a groove is provided on the axial contact surface between the valve cover and the valve body for arranging a second O-ring seal.

[0013] Further, a groove is provided circumferentially on the contact surface between the opening and closing shaft and the valve body for arranging a first O-ring seal.

[0014] Further, the valve seat is made of a carbon fiber-filled modified polytetrafluoroethylene material.

[0015] Other materials with good wear resistance can also be used.

[0016] Advantages of the present invention:

[0017] 1. The valve seat of the present invention is designed as a double-lip elastic structure. The double-lip elastic structure fits with the valve core, and the two valve seats are equivalent to having 4 seals. At the same time, the lip-shaped structure of the valve seat is equivalent to a cantilever structure, which can generate a certain pre-tightening force after assembly. After the valve seat is worn, it has a certain compensation effect, improving the sealing performance of the downcomer valve. When the double-lip elastic structure and the valve core form a sealing pair, the contact area is small, reducing the friction force with the valve core and lowering the opening and closing torque of the valve.

[0018] 2. By providing chamfers on both the inner side wall and the outer side wall of the valve seat in the present invention, it is beneficial for the valve seat to be deformed under pressure, leaving an elastic space for it, being flexible in use, and effectively improving the sealing performance of the valve.

[0019] 3. The present invention provides a notch on the second flange of the valve cover, so as to provide sufficient space for using tools such as pneumatic wrenches when disassembling the connecting studs of the first flange, thereby improving the manufacturing and maintenance efficiency of the valve.

[0020] 4. The present invention provides a second O-ring seal at the connection between the valve body and the valve cover, so that when the connection position between the two parts of the valve body and the valve cover is not tightly matched during use and maintenance, leakage will not occur, thereby improving the sealing performance of the valve.

[0021] 5. The valve seat of the present invention is made of carbon fiber-filled modified polytetrafluoroethylene material, which has good wear resistance and high strength, can reduce the damage of foreign objects in the crude oil to the seal, and improve the sealing performance of the valve. Description of the Drawings

[0022] Figure 1 is a schematic cross-sectional structure diagram of an embodiment of the present invention;

[0023] Figure 2 is a schematic structure diagram of an embodiment of the present invention;

[0024] Figure 3 is a schematic structure diagram of the valve seat in an embodiment of the present invention;

[0025] Figure 4 is a partial schematic cross-sectional structure diagram of the valve seat in the axial direction in an embodiment of the present invention;

[0026] Figure 5 is a schematic structure diagram of the second flange in an embodiment of the present invention.

[0027] Description of the Reference Numerals:

[0028] 1-valve body, 11-valve body flange, 2-opening and closing block, 3-opening and closing shaft, 4-flat gasket, 5-valve cover, 51-first flange, 52-second flange, 6-valve seat, 61-first boss, 62-second boss, 63-first chamfer, 64-second chamfer, 7-first O-ring seal, 8-second O-ring seal, 9-stud, 10-valve core. Detailed Embodiments

[0029] A double-sided switch bottom unloading valve for railway tank cars according to the present invention has an embedded double-opening two-piece spherical valve structure, as Figure 1 shown, including a valve body 1, two opening and closing blocks 2, two opening and closing shafts 3, a valve core 10, a valve cover 5, and two valve seats 6.

[0030] The valve body 1 and the valve cover 5 are coaxially arranged and communicate with each other. One end of the valve cover 5 is inserted into the outlet of the valve body 1, and a first flange 51 is circumferentially arranged near the end, as Figure 2As shown in the figure, a valve body flange 11 is provided at the outlet end of the valve body 1. The first flange 51 and the valve body flange 11 are connected by studs 9, and a flat gasket 4 is provided between their radial contact surfaces. A groove is formed on the surface where the valve cover 5 axially contacts the valve body 1 for arranging a second O-ring 8, so that even when the connection position between the valve body 1 and the valve cover 5 is not tightly matched during maintenance, leakage will not occur, improving the sealing performance of the valve. At the other end of the valve cover 5, a second flange 52 is provided for connecting an external unloading device. Four notches are arranged along the circumferential direction of the second flange 52, corresponding to the studs 9 at the connection between the valve body 1 and the valve cover 5 respectively, as Figure 5 shown, to provide space for using tools such as pneumatic wrenches when disassembling the studs 9. After the second flange 52 is provided with notches, it does not affect the assembly with the existing unloading device.

[0031] The valve core 10 is spherical, with a through hole formed in the center. A spherical accommodating cavity is arranged along the axis in the center of the valve body 1. The valve core 10 is arranged in the accommodating cavity and abuts against the valve cover 5 near the outlet of the valve body 1. Two opening and closing shafts 3 are respectively arranged on both sides of the valve body 1. One end of the opening and closing shaft 3 passes through the side wall of the valve body 1 and is connected to the valve core 10. Grooves are formed along the circumferential direction on its contact surface with the valve body 1 for arranging a first O-ring 7. Two opening and closing stops 2 are respectively arranged at the other ends of the two opening and closing shafts 3 for controlling the opening and closing degree of the valve core 10. During use, the valve core 10 is rotated by controlling the opening and closing shaft 3 to make its through hole communicate with the valve cover 5 to realize the opening of the unloading valve.

[0032] Two valve seats 6 are respectively located at the inlet and outlet positions of the valve body 1, and are installed between the corresponding valve core 10 and the valve body 1, and between the valve core 10 and the valve cover 5. The valve seat 6 is of an annular structure, and its outer side wall abuts against the valve body 1 or the valve cover 5, and its inner side wall is adapted to the outer side wall of the corresponding position of the valve core 10. Arc-shaped first protrusions 61 and second protrusions 62 are arranged along the circumferential direction on the inner side wall, as Figure 3 and Figure 4 shown, forming a double-lip elastic structure, which abuts against the valve core 10 to form two seals. The two valve seats 6 are equivalent to providing four seals between the valve seats 6 and the valve core 10. First chamfers 63 are arranged at the positions of the inner side wall of the valve seat 6 close to the inlet and outlet of the valve body 1; second chamfers 64 are arranged at the positions of the outer side wall of the valve seat 6 far from the inlet and outlet of the valve body 1. The first chamfers 63 and the second chamfers 64 are conducive to the pressure deformation of the valve seat 6, improving the sealing performance of the valve. In this embodiment, the ratio of the surface width L1 of the inner side wall corresponding to the first protrusion 61, the surface width L2 of the inner side wall between the first protrusion 61 and the second protrusion 62, and the surface width L3 of the inner side wall corresponding to the second protrusion 62 is preferably 1:1:1. The height from the highest point of each protrusion to the inner side wall of the valve seat 6 is 0.8 - 1.0 mm, which has both sealing performance and reduces the friction force of the valve core 10.

[0033] The structure of the valve seat 6 is equivalent to a cantilever structure, which can generate a certain pre-tightening force after assembly. When the temperature changes or wear occurs, this structure has a certain compensation effect, improving the sealing performance of the lower unloading valve. The valve seat 6 is made of a non-metallic material, preferably a carbon fiber-filled polytetrafluoroethylene material, to improve the sealing performance of the valve. In other embodiments of the present invention, the inner side of the non-metallic valve seat 6 can also adopt other double-sealing structures such as a V-shaped structure.

Claims

1. A bilateral-switching railway tank car bottom discharge valve, comprising a valve body (1), an opening and closing block (2), an opening and closing shaft (3), a spherical valve core (10), a valve cover (5), and two valve seats (6). The valve body (1) and the valve cover (5) are coaxially connected and communicate with each other. A spherical accommodation cavity is provided inside the valve body (1) for arranging the valve core (10). One end of the opening and closing shaft (3) passes through the side wall of the valve body (1) and is connected to the valve core (10). It is characterized in that: The two valve seats (6) are respectively located at the inlet and outlet positions of the valve body (1) to seal the outer side of the valve core (10); The valve seat (6) is of an annular structure. The outer side wall abuts against the valve body (1) or the valve cover (5), and the inner side wall is adapted to the outer side wall at the corresponding position of the valve core (10). A first boss (61) and a second boss (62) are arranged along the circumferential direction on the inner side wall. Both the first boss (61) and the second boss (62) abut against the valve core (10) to form two seals.

2. The bilateral-switching railway tank car bottom discharge valve according to claim 1, characterized in that: A first chamfer (63) is provided on the inner side wall of the valve seat (6) near the inlet and outlet positions of the valve body (1); a second chamfer (64) is provided on the outer side wall of the valve seat (6) away from the inlet and outlet positions of the valve body (1).

3. The bilateral-switching railway tank car bottom discharge valve according to claim 2, characterized in that: Both the first boss (61) and the second boss (62) are arc-shaped bosses, and the height from the highest point to the inner side wall of the valve seat (6) is 0.8 - 1.0 mm; The ratio of the circumferential surface width L1 of the inner side wall corresponding to the first boss (61), the circumferential surface width L2 of the inner side wall between the first boss (61) and the second boss (62), and the circumferential surface width L3 of the inner side wall corresponding to the second boss (62) is: 1:1:

1.

4. The bilateral-switching railway tank car bottom discharge valve according to any one of claims 1 - 3, characterized in that: One end of the valve cover (5) is inserted into the outlet of the valve body (1), and a first flange (51) is arranged along the circumferential direction near the end. A valve body flange (11) is correspondingly arranged at the outlet end of the valve body (1). The first flange (51) and the valve body flange (11) are connected by studs (9) so that the valve cover (5) is connected to the valve body (1); The other end of the valve cover (5) is provided with a second flange (52) for connecting to an external structure, and a notch is provided at the position of the second flange (52) corresponding to the stud (9).

5. The bilateral-switching railway tank car bottom discharge valve according to claim 4, characterized in that: A flat gasket (4) is arranged between the radial contact surfaces of the first flange (51) and the valve body flange (11), and a groove is opened on the axial contact surface between the valve cover (5) and the valve body (1) for arranging a second O-ring (8).

6. The bilateral-switching railway tank car bottom discharge valve according to claim 5, characterized in that: A groove is opened along the circumferential direction on the contact surface between the opening and closing shaft (3) and the valve body (1) for arranging a first O-ring (7).

7. The bilateral-switching railway tank car bottom discharge valve according to claim 6, characterized in that: The valve seat (6) is made of carbon fiber filled polytetrafluoroethylene material.

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