A double-seal vacuum hopper bottom valve assembly

Abstract

The utility model belongs to vacuum alloy feeding system technical field of liquid steel vacuum refining system discloses a double -layer sealing formula vacuum hopper unloading valve device, the upper and lower two unloading valves of vacuum alloy hopper are connected with respective drive cylinder through intermediate connecting rod, realize the opening and the close of unloading valve through the up-down telescopic action of drive cylinder, increase one intermediate compression flange with upper and lower two sealing grooves in the lower part of unloading valve, through the bottom compression flan of two groups of bolts cooperation, compress the rectangular sealing strip of two cutting angle of big and small in two sealing grooves of intermediate compression flange, form double -layer sealing formula vacuum hopper unloading valve device, realize the effective sealing of upper and lower two hoppers.

Description

Technical Field

[0001] This utility model belongs to the technical field of vacuum alloy feeding system in steel molten vacuum refining system, and provides a double-layer sealed vacuum hopper feeding valve device. Background Technology

[0002] In vacuum refining systems for molten steel, the vacuum alloy feeding system is one of the most frequently used and crucial pieces of equipment. It is used to add alloying elements to molten steel during vacuum processing to achieve alloying under vacuum. During vacuum processing, adding alloying elements from atmospheric pressure to the molten steel in a vacuum tank (or ladle) under vacuum conditions must be achieved through a vacuum hopper. The vacuum hopper is designed with a dual-chamber structure with upper and lower vacuum locks. The upper lock chamber receives alloying elements supplied by the upper hopper system and then transfers them to the lower lock chamber, finally adding the alloying elements into the vacuum tank (or ladle). The opening and closing of the upper and lower vacuum locks are achieved by cylinders, and the open / closed status is indicated by limit switches. To achieve feeding from atmospheric conditions to vacuum conditions, the vacuum hopper is connected to the vacuum system, and an atmospheric / vacuum bypass switching circuit is installed between the upper and lower chambers. A discharge valve isolates the upper and lower chambers, enabling repressurization and vacuuming of the lower chamber of the vacuum hopper.

[0003] The key to the function of the upper and lower vacuum lock double-chamber structure of the vacuum hopper is to ensure the airtightness of the chambers. The key to ensuring the airtightness of the chambers lies in a sealing strip at the bottom of the vacuum lock discharge valve. The sealing strip is pressed against the conical sealing surface by the thrust generated by the cylinder connected to the vacuum lock discharge valve.

[0004] Currently, the sealing method of alloy vacuum hoppers in domestic vacuum refining furnaces is basically the same as the sealing strip below the aforementioned discharge valve. However, the performance of each manufacturer is less than ideal. Inadequate sealing leads to air leakage in the vacuum hopper, increasing the evacuation time of the vacuum pump in the refining system, and even preventing the furnace from achieving the required vacuum level, thus affecting the refining effect. When alloy material is being fed in or out, if the lower discharge valve is not sealed tightly, the time it takes for the lower hopper to vent to the atmosphere is prolonged, preventing the upper discharge valve from opening and the alloy material from falling into the lower hopper in time. Conversely, if the upper discharge valve is not sealed tightly, the time it takes to evacuate the lower hopper is prolonged, preventing the lower discharge valve from opening and the alloy material from falling into the molten steel in the vacuum tank (or ladle) in time. This results in slow feeding during vacuum refining, severely impacting production rhythm and product quality, and even causing accidents such as scrapped molten steel that cannot be fed and need to be remelted, continuous casting machine interruptions, disrupting steelmaking workshop production plans, reducing work efficiency, and significantly increasing production costs. Utility Model Content

[0005] The purpose of this invention is to design a double-layer sealed vacuum hopper discharge valve device. By optimizing and changing the shape of the sealing strip at the bottom of the discharge valve, the problem of air leakage in the vacuum hopper caused by poor sealing of the discharge valve in the existing vacuum hopper is effectively solved. This improves the dynamic sealing performance of the vacuum feeding system, ensures the rapid establishment and maintenance of vacuum in the vacuum tank, shortens the pumping time of the vacuum pump, improves the vacuum treatment effect of molten steel and product quality, ensures production rhythm, improves efficiency, and reduces production costs.

[0006] To achieve the above objectives, the technical solution of this utility model is to modify the existing vacuum hopper vacuum lock discharge valve by adding a middle clamping flange with two sealing grooves at the bottom. The two rectangular sealing strips of different sizes are pressed and assembled into an integrated double-layer sealing vacuum hopper discharge valve by using two sets of bolts to cooperate with the bottom clamping flange.

[0007] A double-layer sealed vacuum hopper discharge valve device is disclosed. The upper and lower discharge valves of the vacuum alloy hopper are connected to their respective drive cylinders via a central connecting rod. The discharge valves are opened and closed by the up-and-down extension and retraction of the drive cylinders. A central clamping flange with two sealing grooves is added to the lower part of the discharge valve. By using two sets of bolts to cooperate with the bottom clamping flange, two rectangular sealing strips with different sizes and beveled angles are pressed into the two sealing grooves of the central clamping flange, forming a double-layer sealed vacuum hopper discharge valve device, which effectively seals the upper and lower hoppers.

[0008] Furthermore, the intermediate clamping flange has two rectangular slots machined on its side to install and fix two rectangular sealing strips with beveled angles, one large and one small, in the slots. The intermediate clamping flange has several bolt holes machined on both the upper and lower surfaces. The intermediate clamping flange is connected and fixed to the discharge valve body through the upper bolt holes, and connected and fixed to the bottom clamping flange through the lower bolt holes. After all the upper and lower bolts are connected and fixed, the rectangular sealing strips are firmly installed on the discharge valve. The discharge valve is opened and closed by the up and down extension and retraction of the drive cylinder. The rectangular sealing strips are pressed to achieve a sealed environment in the upper and lower hoppers.

[0009] Furthermore, the two rectangular sealing strips, one large and one small, are beveled at the same angle as the sealing surface.

[0010] Furthermore, the rectangular sealing strip is made of high-temperature resistant rubber.

[0011] This utility model provides a double-layer sealed vacuum hopper discharge valve device, which can effectively improve the dynamic sealing performance of the vacuum alloy feeding system, avoid air leakage problems in the vacuum alloy feeding system, ensure the rapid establishment and maintenance of vacuum in the vacuum tank, shorten the pumping time of the vacuum pump, improve the vacuum refining effect of molten steel and product quality, ensure production rhythm, improve efficiency, and reduce production costs. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the vacuum hopper vacuum lock double-chamber structure used in the existing RH refining unit;

[0013] In the diagram: 1. Upper locking hopper; 2. Upper locking hopper switch drive cylinder; 3. Lower locking hopper; 4. Lower locking hopper switch drive cylinder; 5. Feed pipe; 6. Vacuum tank;

[0014] Figure 2 This is a schematic diagram of the internal structure of the upper locking chamber;

[0015] In the diagram: 7. Hopper shell; 8. Vacuum lock discharge valve; 9. Cylinder and discharge valve connecting rod; 10. Trapezoidal sealing strip; 11. Bottom clamping flange of discharge valve;

[0016] Figure 3 This is an enlarged view of the state of the sealing strip and its sealing surface when the existing upper lock discharge valve is closed;

[0017] In the diagram: 7. Hopper shell; 8. Vacuum lock discharge valve; 9. Cylinder and discharge valve connecting rod; 10. Trapezoidal sealing strip; 11. Bottom clamping flange of discharge valve; 12. Sloping sealing flange; 13. Discharge chute;

[0018] Figure 4 This is an enlarged view of the sealing strip and its sealing surface when the double-layer sealed vacuum hopper discharge valve of this utility model is closed;

[0019] In the diagram: 7. Hopper shell; 8. Vacuum lock discharge valve; 9. Cylinder and discharge valve connecting rod; 11. Bottom clamping flange of discharge valve; 12. Sloping sealing flange; 13. Discharge chute; a. First layer rectangular sealing strip; b. Middle clamping flange of sealing strip; c. Second layer rectangular sealing strip;

[0020] Figure 5 This is a detailed part drawing of the intermediate clamping flange of a double-layer sealed vacuum hopper discharge valve device according to this utility model. Detailed Implementation

[0021] The technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments.

[0022] like Figure 1 As shown, the function of the vacuum hopper is to introduce various alloy materials from the atmospheric environment into the vacuum environment of the refining furnace during the vacuum refining process of molten steel without disrupting the vacuum level inside the furnace.

[0023] like Figure 2 and Figure 3As shown, the existing vacuum hopper discharge valve uses a trapezoidal sealing strip, which theoretically should guarantee its sealing performance. However, in actual use, it falls short of expectations, with frequent leaks causing refining maintenance personnel considerable hardship and inconvenience. Firstly, the contact area between the sealing strip and the sealing surface is small, and under the downward thrust of the cylinder, the sealing strip is easily deformed, changing the sealing method from surface contact to line contact, which easily leads to air leakage. Secondly, during the frequent opening and closing of the discharge valve, fine metal particles and metal powder in the alloy material can scratch and wear the edges of the sealing strip. Thirdly, the installation of trapezoidal sealing strips requires high precision. The contact surface between the bottom clamping flange and the sealing strip is inclined, requiring careful installation. Even slight carelessness can lead to deformation of the sealing strip, preventing it from forming a standard conical surface and achieving a tight fit with the sealing surface. Furthermore, the high-temperature heat generated during steel refining and daily vacuum tank baking processes causes the sealing strip to deform, age, and lose elasticity. Therefore, the effectiveness of the only seal on the feed valve will be compromised in a very short time, causing the vacuum hopper to fail to function properly, affecting the smooth progress of the entire vacuum refining process, and even causing serious air leakage. In cases where the pressure difference is too large, the feed valve cannot be opened and materials cannot be added, resulting in scrapped molten steel that needs to be recycled and the steelmaking workshop's production plan being disrupted, leading to accidents such as continuous casting machine interruption.

[0024] like Figure 4 As shown, this utility model discloses a double-layer sealed vacuum hopper discharge valve structure, which addresses several problems encountered in the use of existing vacuum hoppers. Firstly, the cross-section of the sealing strip is changed from a trapezoid to a rectangle with beveled angles. Secondly, a central clamping flange with upper and lower sealing grooves is added to the lower part of the vacuum hopper discharge valve. Two sets of bolts, one large and one small, are used in conjunction with the bottom clamping flange to press and assemble the two rectangular sealing strips into a single unit, forming a novel double-layer sealed vacuum hopper discharge valve. The advantages of this modification are that the fixing and clamping surfaces of the sealing strips are all in planar contact, making installation and replacement very convenient and eliminating concerns about misalignment or failure to properly fit the sealing surfaces. The larger contact area between the sealing strip and the sealing surface prevents deformation under the downward thrust of the cylinder, ensuring a consistently surface-contact seal that tightens with increasing pressure. Secondly, and most importantly, the addition of a sealing strip increases the sealing surface of the discharge valve to two seals, resulting in a total of four seals separating the atmosphere from the vacuum, significantly reducing the probability of leakage. By adopting this utility model, the problem of air leakage in the vacuum hopper caused by the poor sealing of the vacuum lock discharge valve can be effectively solved. This improves the dynamic sealing performance of the vacuum feeding system, shortens the pumping time of the vacuum pump, improves the vacuum treatment effect of molten steel and product quality, significantly reduces the labor intensity and maintenance workload of inspection personnel, ensures production rhythm, reduces production costs, and improves efficiency.

[0025] Specifically, this utility model embodiment provides a double-layer sealed vacuum hopper discharge valve device. The upper and lower discharge valves of the vacuum alloy hopper are connected to their respective drive cylinders (or hydraulic cylinders) via a central connecting rod. The opening and closing of the discharge valves are achieved by the up-and-down extension and retraction of the drive cylinders (or hydraulic cylinders), and the opening and closing status is indicated by a limit switch. The discharge valve is sealed by adding a central clamping flange with upper and lower sealing grooves at the bottom of the discharge valve. Two sets of bolts are used to tighten and assemble two rectangular sealing strips with beveled angles, one large and one small, into an integrated double-layer sealed vacuum hopper discharge valve device, achieving effective sealing of the upper and lower hoppers.

[0026] The aforementioned double-layer sealed vacuum hopper discharge valve device, such as Figure 5 As shown, an intermediate clamping flange with upper and lower sealing grooves is added. Two rectangular slots are machined on the side of the flange to install and fix the sealing strip in the grooves. Several bolt holes are machined on the upper and lower surfaces of the flange. The flange can be connected and fixed to the feed valve body through the upper bolt holes, and connected and fixed to the bottom clamping flange through the lower bolt holes. After all the upper and lower bolts are connected and fixed, the sealing strip can be firmly installed on the feed valve. The feed valve is opened and closed by the up and down extension and retraction of the drive cylinder (or hydraulic cylinder). After the sealing strip is tightened, it can ensure a sealed environment in the upper and lower hoppers and prevent air leakage.

[0027] The aforementioned double-layer sealed vacuum hopper discharge valve device utilizes two rectangular sealing strips, one large and one small, with beveled angles, pressed simultaneously against a mating sealing bevel surface at the bottom of the discharge valve. These sealing strips have a rectangular cross-section, with one corner cut at the same angle as the sealing surface. They are made of high-temperature resistant rubber, resulting in a larger contact area between the sealing strip and the sealing surface. Under the downward thrust of the cylinder, the sealing strip will not be squeezed, twisted, or deformed. The sealing method of the sealing strip is always surface contact and becomes tighter with increasing pressure. The discharge valve's sealing surface is increased to two seals, creating a total of four seals separating the atmosphere from the vacuum, significantly reducing the probability of leakage in the vacuum hopper. This invention effectively solves the problem of air leakage in existing vacuum hoppers due to inadequate sealing of the vacuum lock discharge valve, improves the dynamic sealing performance of the vacuum feeding system, shortens the vacuum pump's evacuation time, improves the vacuum treatment effect and product quality of molten steel, significantly reduces the labor intensity and maintenance workload of inspection personnel, ensures production rhythm, reduces production costs, and improves efficiency.

[0028] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A dual seal vacuum hopper bottom valve apparatus, characterized by, The upper and lower discharge valves of the vacuum alloy hopper are connected to their respective drive cylinders via a central connecting rod. The opening and closing of the discharge valves are achieved by the up-and-down extension and retraction of the drive cylinders. A central clamping flange with two sealing grooves is added to the lower part of the discharge valve. By using two sets of bolts to cooperate with the bottom clamping flange, two rectangular sealing strips with different sizes and beveled angles are pressed into the two sealing grooves of the central clamping flange, forming a double-layer sealed vacuum hopper discharge valve device, which effectively seals the upper and lower hoppers.

2. A dual seal vacuum hopper bottom valve assembly as defined in claim 1 wherein, The intermediate clamping flange has two rectangular slots machined on its side to install and fix two rectangular sealing strips with beveled angles, one large and one small, in the slots. The intermediate clamping flange has several bolt holes machined on both the upper and lower surfaces. The intermediate clamping flange is connected and fixed to the discharge valve body through the upper bolt holes, and connected and fixed to the bottom clamping flange through the lower bolt holes. After all the upper and lower bolts are connected and fixed, the rectangular sealing strips are firmly installed on the discharge valve. The discharge valve is opened and closed by the up and down extension and retraction of the drive cylinder. The rectangular sealing strips are pressed to create a sealed environment in the upper and lower hoppers.

3. A dual seal vacuum hopper bottom valve assembly as described in claim 1 wherein, The rectangular sealing strips, one large and one small, are cut at beveled angles, with the bevels being the same angle as the sealing surface.

4. A dual seal vacuum hopper bottom valve assembly as claimed in claim 3 wherein, The rectangular sealing strip is made of high-temperature resistant rubber.

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