A sealable flap valve

Abstract

A sealing gate valve belongs to the technical field of atmosphere isolation equipment for annealing furnaces in galvanizing production lines. It includes a gate valve body, a gate, a drive cylinder, rollers, and a sealing assembly. The gate valve body has an internal valve chamber for the passage of strip steel. The gate, with a flapper-type structure, is hinged within the valve chamber. A drive mechanism rotates the gate to open and close the valve chamber. The roller axis is perpendicular to the strip's running direction, and its outer circumference rolls against the lower surface of the strip, providing support. The sealing assembly, in conjunction with nitrogen sealing, reliably isolates the protective atmosphere inside the furnace from the external air when the furnace remains operational even during line shutdown. This invention provides stable support for the strip steel through double rollers, preventing strip vibration, deviation, and scratching, while ensuring the atmosphere sealing function of the gate valve. This improves the operational stability and product quality of the galvanized automotive sheet production line and extends the equipment's service life.

Description

Technical Field

[0001] This invention relates to the field of atmosphere isolation technology for annealing furnaces in galvanizing production lines. Background Technology

[0002] In the production of galvanized steel sheets, the annealing furnace is a core piece of equipment. A nitrogen-hydrogen mixed protective atmosphere must be maintained inside the furnace to prevent oxidation of the strip steel during high-temperature annealing, ensuring the quality of the subsequent hot-dip galvanized coating. In cases of temporary production line malfunctions or equipment maintenance, a "line shutdown without furnace shutdown" operation must be implemented. In this situation, the annealing furnace outlet must be sealed using a gate valve to isolate the protective atmosphere inside the furnace from external air, preventing atmosphere leakage and air ingress that could lead to strip steel oxidation. Simultaneously, this maintains stable furnace temperature and atmosphere, reducing energy waste and production losses.

[0003] Traditional annealing furnace outlet gate valves only have basic switching functions, and their structure consists only of a valve body, a gate, and a drive mechanism. In actual production, they suffer from the following technical defects: 1. Strip steel is prone to shaking and deviation: The strip steel has high temperature and low rigidity in the annealing furnace outlet area. Without effective support, it is prone to shaking, sagging or even deviation due to its own weight and airflow disturbance. In severe cases, it may scrape the valve body or gate, causing scratches on the strip steel surface and affecting the quality of automotive steel products. 2. The seal is prone to failure: the scraping of the strip steel will cause wear and deformation of the gate sealing surface, and it will not be able to fit tightly when closed, resulting in leakage of the furnace atmosphere and infiltration of external air, which will damage the stability of the furnace atmosphere. 3. Short equipment lifespan: Frequent wear of seals and gate valves leads to frequent maintenance and replacement of gate valves, affecting production line operating rate and increasing maintenance costs; 4. Easy jamming during strip threading and tail swing: The lack of a support structure makes the strip unstable in the gate valve area, which is prone to jamming and reduces the efficiency of production line start-up and recovery.

[0004] To address the aforementioned issues, there is an urgent need for a sealing gate valve that combines atmosphere isolation and strip support functions to solve the problems of strip vibration and scraping, thereby improving production line stability and product quality. Summary of the Invention

[0005] In order to overcome the defects of traditional annealing furnace outlet gate valves, such as lack of strip support, easy strip vibration, deviation and scraping, and easy seal failure, this invention provides an annealing furnace outlet sealing gate valve with double roller support.

[0006] The technical solution adopted by the present invention to achieve the above-mentioned objectives is as follows: a sealed gate valve, wherein the gate valve body 10 has a through-type valve cavity inside, and the upper and lower ports of the gate valve body 10 are respectively equipped with docking flanges 3. The upper rotating shaft 8 and the lower rotating shaft 12 are respectively arranged horizontally and vertically at the upper and lower ports inside the gate valve body 10. The two ends of the upper rotating shaft 8 and the lower rotating shaft 12 are respectively installed on the side wall of the gate valve body 1. One end of the upper rotating shaft 8 and the lower rotating shaft 12 are respectively connected to the upper driving cylinder 1 and the lower driving cylinder 15 installed on the outside of the side wall of the gate valve body 10. Gate plates 6 are respectively installed on the upper rotating shaft 8 and the lower rotating shaft 12. The upper roller shaft 9 and the lower roller shaft 11 are arranged horizontally and vertically between the two side walls inside the gate valve body 10. One end of the upper roller shaft 9 and the lower roller shaft 11 are respectively connected to the upper roller motor 4 and the lower roller motor 14 installed on the outside of the side wall of the gate valve body 10. The upper roller and the lower roller are installed on the upper roller shaft 9 and the lower roller shaft 11.

[0007] Nitrogen injection holes 2 are respectively provided on the side wall of the gate valve body 10 at the upper rotating shaft 8 and the lower rotating shaft 12.

[0008] The lip of the gate 6 is fitted with a metal fiber felt 7.

[0009] The outer wall of the gate valve body 10 is provided with a high-temperature heat-resistant ceramic fiber composite material insulation layer.

[0010] The upper idler roller motor 4 and the lower idler roller motor 14 are variable frequency speed control motors.

[0011] The lengths of the upper and lower idlers are adapted to the width of the strip.

[0012] The cylinder rods of the upper drive cylinder 1 and the lower drive cylinder 15 are respectively connected to the shaft ends of the upper rotating shaft 8 and the lower rotating shaft 12 via the connecting plate 16.

[0013] The sealing gate valve of the present invention has the following beneficial effects: 1. Effectively suppress strip vibration and deviation: The upper and lower double idlers provide stable support for the strip, offsetting its own weight and airflow disturbances, avoiding vibration, sagging, and scratching, reducing surface scratches on the strip from the source, and improving product qualification rate; 2. Reliable and stable sealing performance: The idler roller support avoids the strip impact and scraping of the gate, protecting the sealing surface. Combined with metal fiber felt seal and nitrogen seal, it achieves efficient atmosphere isolation and meets the requirement of not stopping the furnace when the line is stopped. 3. Extend equipment service life: Rolling friction replaces sliding friction, reducing wear on valve body and gate; sealing and shaft end protection structures adapt to high-temperature and dusty environments, significantly reducing maintenance frequency; 4. Improve strip passage and threading efficiency: The strip passes smoothly and steadily, and threading and tailing are less prone to jamming, thus improving the efficiency of production line start-up, shutdown and fault recovery. 5. Simple structure and strong versatility: The roller mechanism is integrated on the basis of the traditional tilting gate valve, requiring little modification and adapting to the outlet working conditions of various galvanized automotive sheet annealing furnaces. Attached Figure Description

[0014] Figure 1 This is a main view of the sealing gate valve of the present invention.

[0015] Figure 2 This is a right-side structural view of the sealing gate valve of the present invention.

[0016] Figure 3 This is a top view of the sealing gate valve of the present invention.

[0017] In the diagram: 1. Upper drive cylinder, 2. Nitrogen injection port, 3. Connecting flange, 4. Upper idler roller motor, 5. Upper idler roller, 6. Gate plate, 7. Metal fiber felt, 8. Upper rotating shaft, 9. Upper idler roller shaft, 10. Gate valve body, 11. Lower idler roller shaft, 12. Lower rotating shaft, 13. Mounting bracket, 14. Lower idler roller motor, 15. Lower drive cylinder, 16. Connecting plate. Detailed Implementation

[0018] The sealing gate valve structure of the present invention is as follows: Figure 1-3As shown, the valve includes a gate valve body 10, a gate 6, an upper drive cylinder 1, a lower drive cylinder 15, an upper idler roller motor 4, a lower idler roller motor 14, an upper idler roller shaft 9, a lower idler roller shaft 11, an upper rotating shaft 8, a lower rotating shaft 12, and sealing components. The gate valve body 10 has a through-type valve cavity, with flanges 3 at both ends for connecting to the annealing furnace outlet and expansion joint. A strip steel passage path is formed inside the valve cavity. The gate 6 is a flap-type structure, mounted on the upper rotating shaft 8 and the lower rotating shaft 12. The upper drive cylinder 1 and the lower drive cylinder 15 are fixed to the outer side of the gate valve body 10, with their output ends connected to the upper rotating shaft 8 and the lower rotating shaft 12 respectively. These shafts drive the gate 6 to rotate, opening and closing the two ports of the valve cavity. The gate is driven by cylinders, ensuring smooth and seamless operation. Combined with a position sensor, the opening and closing status can be accurately monitored to ensure proper sealing. The drive cylinders are equipped with position sensors for real-time feedback of the opening and closing status. The upper idler roller motor 4 and the lower idler roller motor 14 are respectively fixed to the outer side wall of the gate valve body 10. The upper idler roller shaft 9 and the lower idler roller shaft 11 are rotatably mounted on the side wall of the valve cavity of the gate valve body 10 through bearing seats. The outer ends of the upper idler roller shaft 9 and the lower idler roller shaft 11 are respectively connected to the output ends of the upper idler roller motor 4 and the lower idler roller motor 14. The idler roller motor adopts frequency conversion speed regulation, which can be synchronized with the production line speed to avoid scratches caused by relative sliding between the idler roller and the strip. The two sets of idler rollers are arranged parallel to each other on the strip passage path in the gate valve cavity. The axis of the idler roller is perpendicular to the running direction of the strip, and the outer circumferential surface of the idler roller rolls against the lower surface of the strip to provide support for the strip. The sealing assembly includes a nitrogen injection hole 2 and a metal fiber felt 7. The nitrogen injection hole is located on the side wall of the gate valve body 10 at the ends of the upper rotating shaft 8 and the lower rotating shaft 12, isolating the external atmosphere. This ensures a tight seal between the furnace atmosphere and the external atmosphere when the gate 6 is closed, preventing leakage of the furnace atmosphere from the shaft end. A dustproof structure is also provided on the outside to protect the bearings for long-term stable operation. A high-temperature resistant flexible metal fiber felt seal is used, located on the lip of the gate. When closed, it fits tightly against the valve seat, forming a multi-stage seal combined with the nitrogen seal. This meets the atmosphere isolation requirements under high-temperature conditions, creating a multi-stage sealing structure of mechanical seal + nitrogen seal. This structure offers strong sealing performance, high temperature resistance, and long service life. A high-temperature resistant heat insulation layer is installed on the outside of the gate valve body 10 to reduce heat loss and protect components such as the motor and bearings. The length of the idler roller matches the width of the strip steel, effectively limiting lateral deviation and preventing misalignment.

[0019] In use, the gate valve body 10 is installed at an angle (forming a 45° angle with the horizontal plane) via the mounting bracket 13, and the two idler rollers are placed at an angle to support the strip steel. The strip steel enters and exits through the upper and lower ports of the gate valve body 10. First, the gate plate opens, and the two idler rollers rotate synchronously with the strip steel, supporting the strip steel to pass smoothly without shaking or scraping. During line stoppage without furnace shutdown: the drive cylinder drives the gate plate to rotate and close, the seal is tightened, and nitrogen is introduced to achieve complete isolation of the atmosphere inside and outside the furnace; for strip threading / tailing: the idler rollers provide guiding support, allowing the strip steel to pass smoothly without jamming or deviation. The stable support of the strip steel by the two idler rollers, while ensuring the atmosphere sealing effect under the condition of line stoppage without furnace shutdown, improves the stability of production line operation, product surface quality, and equipment lifespan.

Claims

1. A sealing gate valve, characterized in that: The gate valve body (10) has a through-type valve cavity inside. The upper and lower ports of the gate valve body (10) are respectively equipped with mating flanges (3). The upper rotating shaft (8) and the lower rotating shaft (12) are arranged horizontally and vertically at the upper and lower ports inside the gate valve body (10). The two ends of the upper rotating shaft (8) and the lower rotating shaft (12) are respectively installed on the side wall of the gate valve body (1). One end of the upper rotating shaft (8) and the lower rotating shaft (12) are respectively connected to the upper drive cylinder (1) and the lower drive cylinder (1) installed on the outside of the side wall of the gate valve body (10). A drive cylinder (15) is installed with gate plates (6) on the upper rotating shaft (8) and the lower rotating shaft (12); the upper roller shaft (9) and the lower roller shaft (11) are arranged horizontally and vertically between the two side walls inside the gate valve body (10). One end of the upper roller shaft (9) and the lower roller shaft (11) are respectively connected to the upper roller motor (4) and the lower roller motor (14) installed on the outside of the side wall of the gate valve body (10). The upper roller and the lower roller are installed on the upper roller shaft (9) and the lower roller shaft (11).

2. A sealing gate valve according to claim 1, characterized in that: The gate valve body (10) has nitrogen injection holes (2) located at the upper rotating shaft (8) and the lower rotating shaft (12) on its side wall.

3. A sealing gate valve according to claim 1, characterized in that: The lip of the gate (6) is fitted with a metal fiber felt (7).

4. A sealing gate valve according to claim 1, characterized in that: The outer wall of the gate valve body (10) is provided with a high-temperature heat-resistant ceramic fiber composite material insulation layer.

5. A sealing gate valve according to claim 1, characterized in that: The upper idler motor (4) and the lower idler motor (14) are variable frequency speed control motors.

6. A sealing gate valve according to claim 1, characterized in that: The lengths of the upper and lower idlers are adapted to the width of the strip.

7. A sealing gate valve according to claim 1, characterized in that: The cylinder rods of the upper drive cylinder (1) and the lower drive cylinder (15) are respectively connected to the shaft ends of the upper rotating shaft (8) and the lower rotating shaft (12) through the connecting plate (16).

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