Method for avoiding dead wedge of large gate valve

Abstract

The invention relates to a method for preventing a large gate valve from being wedged, which comprises the following steps of: 1, additionally arranging adjustable limiting rods at two ends of a valve cover cap head of the gate valve, arranging a sealing cavity in the middle of the valve cover cap head, arranging a sealing gland on the upper part of the sealing cavity, connecting the sealing cavity with the sealing gland by adopting a bolt, and arranging a gate valve output shaft in an axial hole channel of the sealing cavity and the sealing gland, 2, the length of a limiting rod is adjusted, the limit position of the valve plate is fixed, when the valve plate moves to the lower limit position during valve assembling and debugging, sealing is guaranteed, meanwhile, a bolt on the upper portion of the limiting rod is adjusted, the upper end face of the bolt is flush with the lower end face of the cross beam, and the cross beam is connected with the valve plate; the position is the lower limit position of the gate valve. The scheme is simple in process and high in practicability, and the adjustable limiting rods are additionally arranged at the two ends of the valve cover cap of the gate valve. The length of the limiting rod is adjusted during valve assembling and debugging, the limiting position of the valve plate is fixed, and the reliability of the large gate valve is effectively improved.

Description

Technical Field

[0001] The present invention relates to a method, specifically to a method for avoiding the jamming of a large gate valve, belonging to the technical field of gate valve devices. Background Art

[0002] The vertical gate valve is a common valve in blast furnace metallurgical equipment. It is mainly applied to pipelines such as gas, flue gas, air, and cold air in the hot blast stove system of the blast furnace, serving as cold air valves, gas (air) cut-off valves, gas (air) combustion valves, flue gas valves, etc., and playing a cut-off role in the system. The wedge gate valve has a simple structure, a heavy and stable cavity, is durable and not easily deformed, and is the first choice valve type to ensure the use of one furnace age. Its characteristic is that it can be applied to low-pressure pipelines and can achieve self-energized sealing without high-pressure medium being pressed. The principle of self-energized sealing is that on the one hand, wedge blocks with composite wedge surfaces are provided on both sides of the valve body and the valve plate for centering and pressing sealing; on the other hand, the sealing surfaces of the valve body and the valve plate have a 2° inclined plane. The ingenious angle design makes the valve plate closer and closer during the downward closing process.

[0003] At the same time, it increases the difficulty of instantaneously opening the valve plate. Due to the driving force of the valve plate downward and the frictional force component generated by the self-weight of the valve plate on the 2° inclined plane, plus the wedging force of the wedge block, a quite large acting force is required to smoothly open the valve when the valve plate opens upward. For this reason, a push rod device is provided at the bottom of the valve itself, and its function is to manually push out the valve plate when it is jammed to disengage the mating surface. For gate valves with relatively smaller diameters, the push rod device can solve the jamming phenomenon of the valve plate caused by various reasons. For gate valves with relatively larger diameters, due to the increase in the contact area of the 2° inclined plane, the driving force of the valve plate downward and the frictional force component generated by the self-weight of the valve plate on the 2° inclined plane increase, and plus the increase in the diameter, the medium pressure also increases accordingly. Often, when the valve plate is jammed, the function of the push rod device is limited and the valve cannot be opened.

[0004] Comparison with the Prior Art

[0005] "Large Gate Valves and Ball Valves with Quick Opening and Closing", Application (Patent) No.: CN201210030233.7. The present invention discloses a large gate valve and a ball valve with quick opening and closing. It is composed of components such as a valve shell, a valve core, a valve seat, a sealing pair, an upper seal, and an actuator. Its characteristics are that: one of the sealing members in the sealing pair is a soft sealing material, and when the valve opens and closes, there is no sliding between the sealing pairs, only vertical relative or opposite direction movements to ensure that the soft sealing material is not subjected to shearing force.

[0006] "A Gate Valve". Application (patent) number: CN201420362575.3. The utility model discloses a gate valve, which includes a valve body, a gate plate, a valve stem and a valve cover. The valve cover is fixedly connected to the top of the valve body by bolts. The gate plate is arranged in the valve cavity of the valve body and connected to the valve stem. The valve stem nut is connected to the handwheel. A valve seat hole is provided in the valve body. After a valve seat is installed in the valve seat hole, the valve body and the valve seat are welded and connected. A sealing contact surface is formed between the outer end surface of the valve seat and the gate plate when the gate valve is closed. An end face ring groove is provided on the outer end surface of the valve seat, and an outer ring groove is provided on the outer circle of the valve seat. The outer ring groove and the end face are communicated through several through holes provided in the valve seat. A grease injection hole is provided on the outer side wall of the valve body. After the grease injection hole penetrates the side wall of the valve body, it is communicated with the outer ring groove. The above prior art does not involve a method for avoiding the jamming of large gate valves. The technical solution adopted to solve the problem is different from that of the comparative document. Summary of the Invention

[0007] The present invention precisely aims at the problems existing in the prior art and provides a method for avoiding the jamming of large gate valves. The technical solution adds adjustable limit rods at both ends of the valve cover boss of the gate valve. When the valve is assembled and debugged, when the gate plate reaches the lower limit position to ensure sealing, the length of the limit rod is adjusted to fix the limit position of the gate plate. Under the action of this limit rod, the downward driving force of the gate plate and the self-weight of the gate plate no longer increase the friction force of the wedge angle, alleviating the large jamming force generated during the closing process of the gate valve, thereby solving the jamming phenomenon of large gate valves caused by various reasons such as electrical limit switch failures, hydraulic drive part failures, and transmission chain failures.

[0008] In order to achieve the above object, the technical solution of the present invention is as follows. A method for avoiding the jamming of large gate valves, characterized in that the method includes the following steps:

[0009] Step 1: Add adjustable limit rods at both ends of the valve cover boss of the gate valve. The middle of the valve cover boss is a sealing cavity. The upper part of the sealing cavity is a sealing gland. The sealing cavity and the sealing gland are connected by bolts. The axial hole channels in the sealing cavity and the sealing gland are the valve outlet shafts of the gate valve. One end of the valve outlet shaft is connected to the gate plate, and the other end is connected to a cross beam. The cross beam is also connected to the drive system.

[0010] Step 2: Adjust the length of the limit rod to fix the limit position of the gate plate. When the valve is assembled and debugged, when the gate plate reaches the lower limit position to ensure sealing, adjust the upper bolt of the limit rod. The upper end face of the bolt should be flush with the lower end face of the cross beam. This is the lower limit position of the gate valve.

[0011] Among them, in the above Step 1, the limit rod is of a split structure. The body part of the limit rod is welded and fixed at both ends of the valve cover boss, and the adjusting bolt part of the limit rod is connected to the body by threads.

[0012] An apparatus for a method of preventing large gate valves from jamming. The apparatus includes a valve plate, a valve stem, a limiting rod, and a crossbeam. The valve plate is connected to the valve stem, and the valve stem is connected to the crossbeam. The upper end of the valve stem has threads, and the valve stem and the crossbeam are fixed by a nut. The valve plate is placed inside the valve housing, and the valve cover and the valve housing are fixed by bolts. One end of the limiting rod is welded and fixed to the upper end of the valve cover.

[0013] Among them, the limiting rod is a split mechanism, including a limiting rod body and an adjusting bolt. The adjusting bolt is connected to the limiting rod body through threads. The apparatus also includes a sprocket set and a lock nut. The limiting rod is independently configured, and a sprocket set and a lock nut are provided on the limiting rod.

[0014] Compared with the prior art, the present invention has the following advantages. The method flow of the present invention is simple and highly feasible. Adjustable limiting rods are added at both ends of the valve cover head of the gate valve. During the assembly and commissioning of the valve, the length of the limiting rod is adjusted to fix the limit position of the valve plate, thus solving the problem of large gate valve jamming caused by various reasons such as electrical limit switch failures, hydraulic drive part failures, and transmission chain failures, effectively improving the reliability of large gate valves. And this solution facilitates the sealing commissioning of the valve plate before the valve leaves the factory; it is conducive to fine-tuning when the sealing is not tight due to the user's own working conditions or when wedge tightening occurs due to excessive thermal expansion during the user's use process, preventing the phenomenon of the driving device being overloaded instantaneously and burning the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the relationship between the limiting rod of the present invention and a large gate valve;

[0016] Figure 2 Schematic diagram of the limiting rod of the present invention;

[0017] Figure 3 Schematic diagram of the structure in the use state.

[0018] In the figure: 1. Valve housing, 2. Valve cover, 3. Valve plate, 4. Valve stem, 5. Crossbeam, 6. Nut, 7. Limiting rod body, 8. Adjusting bolt, 9. Limiting rod, 10. Chain, 11. Chain set, 12. Lock nut. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] To deepen the understanding of the present invention, the following detailed description is given in conjunction with the accompanying drawings for this embodiment.

[0020] Embodiment 1: Refer to Figure 1 、 Figure 2 , a method of preventing large gate valves from jamming, the method includes the following steps:

[0021] Step 1: Adjustable limit rods 9 are added at both ends of the valve cover of the gate valve. The middle of the valve cover is a sealing chamber, and the upper part of the sealing chamber is a sealing gland. The sealing chamber and the sealing gland are connected by bolts. The axial channel between the sealing chamber and the sealing gland is the gate valve outlet shaft. One end of the gate valve outlet shaft is connected to the valve plate 3, and the other end is connected to the crossbeam 5. The crossbeam 5 is also connected to the drive system.

[0022] Step 2: Adjust the length of the limit rod 9 to fix the limit position of the valve plate. When assembling and debugging the valve, make the valve plate move to the lower limit position to ensure sealing. At the same time, adjust the upper bolt of the limit rod. The upper end surface of the bolt should be flush with the lower end surface of the beam. This is the lower limit position of the gate valve.

[0023] Among them, the limit rod in step 1 is a split structure, the body part of the limit rod is welded and fixed to the two ends of the valve cover head, and the adjusting bolt part of the limit rod is connected to the body through a thread.

[0024] Example 1: See Figure 1 , Figure 2 , a device for preventing a large gate valve from being wedged, the device comprising a valve plate 3, a valve stem 4, a limiting rod 9 and a cross beam 5, the valve plate 3 is connected to the valve stem 4, the valve stem 4 is connected to the cross beam 5, the upper end of the valve stem 4 is threaded, the valve stem 4 and the cross beam 5 are fixed by a nut 6, the valve plate 3 is built into the valve housing 1, the valve cover 2 and the valve housing 1 are fixed by bolts, and one end of the limiting rod 9 is welded and fixed to the upper protrusion of the valve cover 2. Among them, the limiting rod 9 is a split mechanism, including a limiting rod body 7 and an adjusting bolt 8, and the adjusting bolt 8 is connected to the limiting rod body 7 by a thread.

[0025] Working process: Working principle: When assembling and debugging the valve, adjust the length of the limit rod 9, and the upper end surface of the adjusting bolt 8 should be flush with the lower end surface of the beam 5. This is the lower limit position of the gate valve. During the production process, due to various reasons, when the valve plate 3 moves downward and reaches the lower limit position, the limit rod 9 supports the beam 5. Under the action of the limit rod, the downward driving force of the valve plate 3 and the weight of the valve plate no longer increase the friction of the wedge angle, which alleviates the large wedge dead force generated by the gate valve during the closing process, thereby solving the wedging phenomenon of large gate valves caused by various reasons. Figure 3 In actual application, the limit rods are configured as two independent ones and need to be adjusted separately. After the valve has been used for a period of time, when the height needs to be adjusted on site due to other reasons, height deviation often occurs, which affects the uneven force of the double-row chain of the transmission frame. For this reason, a synchronous sprocket set 11 and a lock nut 12 are added.

[0026] It should be noted that the above embodiments are not intended to limit the protection scope of the present invention, and equivalent changes or substitutions made on the basis of the above technical solutions all fall within the protection scope of the claims of the present invention.

Claims

1. A method for preventing large gate valves from jamming, characterized in that, the method comprises the following steps: Step 1: Add adjustable limit rods at both ends of the valve cover head of the gate valve. The middle of the valve cover head is a sealing cavity, the upper part of the sealing cavity is a sealing gland, the sealing cavity and the sealing gland are connected by bolts, the axial channels of the sealing cavity and the sealing gland are the outlet shaft of the gate valve, one end of the outlet shaft of the gate valve is connected to the valve plate, the other end is connected to the cross beam, and the cross beam is also connected to the drive system. Step 2: Adjust the length of the limit rod to fix the extreme position of the valve plate. When the valve plate reaches the lower extreme position during the assembly and commissioning of the valve, while ensuring sealing, adjust the upper bolt of the limit rod so that the upper end face of the bolt is flush with the lower end face of the cross beam. This is the lower extreme position of the gate valve.

2. The method for preventing large gate valves from jamming according to claim 1, characterized in that, in step 1, the limit rod is a split structure, the body part of the limit rod is welded and fixed at both ends of the valve cover head, and the adjusting bolt part of the limit rod is connected to the body by threads.

3. An apparatus for implementing the method for preventing large gate valves from jamming according to claim 1 or 2, characterized in that, the apparatus comprises a valve plate, a valve stem, a limit rod and a cross beam. The valve plate is connected to the valve stem, the valve stem is connected to the cross beam, the upper end of the valve stem has threads, and the valve stem and the cross beam are fixed by nuts. The valve plate is placed inside the valve housing, the valve cover and the valve housing are fixed by bolts, and one end of the limit rod is welded and fixed at the upper head of the valve cover.

4. The apparatus for implementing the method for preventing large gate valves from jamming according to claim 3, characterized in that, the limit rod is a split mechanism, including a limit rod body and an adjusting bolt, and the adjusting bolt is connected to the limit rod body by threads.

5. The apparatus for implementing the method for preventing large gate valves from jamming according to claim 3, characterized in that, the apparatus further comprises a sprocket set and a lock nut. The limit rod is independently configured, and the sprocket set and the lock nut are arranged on the limit rod.

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