Parallel double disc gate valve

Abstract

The present invention relates to a parallel double-disc gate valve, comprising a valve body, a valve stem, a gate, and a valve seat. The valve body is provided with a flow channel for fluid passage and a valve cavity located in the middle of the flow channel for the gate to be raised and lowered. The gates are located on both sides of the valve cavity and are sealed with the valve seat located at the connection between the flow channel and the valve cavity. The valve stem drives the gate to rise and fall. The valve stem is provided with a transverse movement mechanism that moves the gate laterally toward the valve seat until a sealing fit is achieved when the gate descends to a position opposite to the valve seat. A limiting mechanism is provided between the gates on both sides to prevent the lower ends of the gates from tilting inward when rising. By adopting the above solution, the present invention provides a parallel double-disc gate valve that prevents the lower ends of the gates from tilting inward to form a V-shaped structure, thereby extending the service life and the smoothness of the lifting and lowering.

Description

Technical Field

[0001] The present invention relates to the field of valves, and in particular to a parallel double-disc gate valve. Background Art

[0002] In the petroleum industry, parallel double-disc gate valves are primarily used in oil and natural gas pipelines, refined oil pipelines and storage facilities, and oil and natural gas extraction wellheads. In thermal power plants, these valves are typically used for shutoff and isolation of key pipelines, such as main steam, main feedwater pump isolation, high-pressure heater isolation, and turbine water delivery systems. They effectively shut off or open high-temperature, high-pressure steam-water media, and their pressure-bearing performance, sealing performance, service life, and maintenance intervals directly impact the reliability and safety of the unit.

[0003] The traditional parallel double-disc gate valve includes a valve body, a valve stem, a gate and a valve seat. The valve body is provided with a flow channel for fluid to pass through and a valve cavity located in the middle of the flow channel for the gate to rise and fall. The gates are respectively located on both sides of the valve cavity and are sealed with the valve seat located at the connection between the flow channel and the valve cavity. A wedge block is provided under the valve stem, and a wedge-shaped matching block is provided between the wedge block and each gate. After the valve stem drives the gate to descend to the corresponding position with the valve seat, the wedge block pushes the gate sideways through the wedge-shaped matching block until it matches the seal. The gate drives the valve stem to rise, and the gate moves away from the corresponding valve seat to release the seal.

[0004] The parallel double-disc gate valve with the above structure still has certain disadvantages in actual application. First, the gate has a certain mass. During the rising process of the gate, the lower ends of the gates on both sides will tilt inward due to gravity, forming a V-shaped state. This V-shaped state not only affects the lifting stability, but also after the lower end of the gate tilts inward, the upper end will also tilt outward a small amount, aggravating the wear between the upper end and the guide structure, affecting the service life and the smoothness of lifting; secondly, when the gate rises under the drive of the valve stem, the valve seat and the gate are still in a sealed fit state. The gate retreats inward due to the damping between the gate and the valve seat and continues to rise. The above damping aggravates the wear between the gate and the valve seat, shortens the service life of the gate and the valve seat, reduces the sealing performance, and increases the opening and closing damping. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a parallel double-disc gate valve that prevents the lower end of the gate from tilting inward to form a V-shaped structure, thereby extending the service life and the smoothness of lifting and lowering.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: including a valve body, a valve stem, a gate and a valve seat, wherein the valve body is provided with a flow channel for fluid to pass through and a valve cavity located in the middle of the flow channel for the gate to rise and fall, the gates are respectively located on both sides of the valve cavity and are sealed with the valve seat located at the connection between the flow channel and the valve cavity, the valve stem drives the gate to rise and fall and is provided with a transverse movement mechanism which moves the gate laterally toward the valve seat until it is sealed when the gate descends to a position relative to the valve seat, and is characterized in that a limiting mechanism is provided between the gates on both sides to prevent the lower end of the gate from tilting inward when the gate rises.

[0007] By adopting the above technical solution, a limiting mechanism is added to prevent the lower end of the gate from tilting inward, thereby avoiding the formation of a V-shaped structure due to the inward tilt, and at the same time avoiding the outward tilt of the upper end of the gate, ensuring the service life and smooth lifting and lowering.

[0008] The present invention is further configured as follows: the limiting mechanism includes a limiting shaft, and the gate plates on both sides are respectively provided with limiting grooves with openings facing each other along the transverse direction. The limiting shaft is arranged transversely and its two ends are respectively located in the limiting grooves of the gate plates on different sides. When the lower end of the gate plate tilts inward, the limiting shaft abuts against the wall of the limiting groove to form a limiting fit.

[0009] By adopting the above technical solution, a limiting shaft is selected between the limiting grooves of the gate plate. When the lower end of the gate plate tends to tilt inward, the limiting shaft will abut against the wall of the limiting groove to prevent the occurrence of tilting, thereby avoiding the gate plate from forming a V-shaped structure.

[0010] The present invention is further configured to include a tension spring, which is arranged in the transverse direction, and whose two ends are respectively located in the limiting grooves of the gate plate on different sides and fixed to the groove walls of the limiting grooves.

[0011] By adopting the above technical solution, before the valve stem rises, the tension spring can increase the inward retreat rate and retreat amplitude of the gate plate, rather than relying on the damping between the gate plate and the valve seat for retreat, thereby ensuring that the gate plate is in a non-contact state with the valve seat before rising, avoiding wear of the two during the rising process, extending the service life, and ensuring the sealing performance.

[0012] The present invention is further configured as follows: the groove wall of the limiting groove corresponds to the end of the tension spring and is surrounded by a mounting boss, and the inner side surface of the mounting boss and the tension spring are screw-fitted to fix the two.

[0013] By adopting the above technical solution, the limit groove and the tension spring are fixed by means of threaded fitting, thereby improving the convenience of disassembly, assembly and maintenance.

[0014] The present invention is further configured as follows: limiting bosses are respectively arranged around both ends of the limiting shaft, a telescopic gap corresponding to the position of the tension spring is formed between the limiting bosses at both ends, and the tension spring is fixed to one of the limiting bosses.

[0015] By adopting the above technical solution, a telescopic gap is formed between the limit bosses, so that the tension spring minimizes contact with the limit pin during the telescopic process, that is, reduces wear, thereby extending the service life and reducing the opening and closing damping.

[0016] The present invention is further configured such that: the tension spring is fixed to the limiting boss by welding.

[0017] By adopting the above technical solution and the welding fixing method, the fixing reliability is better and the fixing area is smaller, which is more suitable for the fixation between the tension spring and the limiting boss.

[0018] The present invention is further configured as follows: the transverse movement mechanism includes a wedge block and a wedge matching block in a wedge-shaped fit, the wedge block is located at the lower end of the valve stem, there are two wedge matching blocks and they are respectively located between the gate plates and the wedge blocks on both sides, the wedge block is provided with mounting holes along the transverse direction, the gate plates on both sides are provided with mounting columns that extend into the mounting holes and move transversely with the mounting holes, the mounting columns are hollow and the hollow part serves as a limit groove.

[0019] By adopting the above technical solution, a mounting hole for the mounting column to extend into is opened on the wedge block, and a limiting groove is set on the mounting column, so that the limiting groove can be set near the center of the gate, thereby improving the limiting effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of a specific embodiment of the present invention;

[0021] Figure 2 for Figure 1 A magnified view of the middle panel. DETAILED DESCRIPTION

[0022] The technical solutions of the present invention are described clearly and completely below with reference to the accompanying drawings. It should be understood that the embodiments described herein are only a portion of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are intended to fall within the scope of protection of the present invention.

[0023] In the description of the present invention, it should be noted that terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" are used to indicate positions or locations based on the positions or locations shown in the accompanying drawings. These terms are used solely to facilitate and simplify the description of the present invention and are not intended to indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific manner. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0024] like Figure 1 — Figure 2 As shown, the present invention discloses a parallel double-disc gate valve, including a valve body 1, a valve stem 2, a gate plate 3 and a valve seat 4. The valve body 1 is provided with a flow channel 11 for fluid to pass through and a valve cavity 12 located in the middle of the flow channel 11 and for the gate plate 3 to rise and fall. The gate plates 3 are respectively located on both sides of the valve cavity 12 and are sealed with the valve seat 4 located at the connection between the flow channel 11 and the valve cavity 12. The valve stem 2 drives the gate plate 3 to rise and fall and is provided with a transverse movement mechanism for moving the gate plate 3 laterally toward the valve seat 4 until it is sealed when the gate plate 3 descends to a position relative to the valve seat 4. A limiting mechanism is provided between the gate plates 3 on both sides to prevent the lower end of the gate plate 3 from tilting inward when rising. The limiting mechanism is additionally provided to prevent the lower end of the gate plate 3 from tilting inward, thereby avoiding the formation of a V-shaped structure due to the inward tilt, and at the same time avoiding the outward tilt of the upper end of the gate plate 3, thereby ensuring the service life and the smoothness of lifting and lowering.

[0025] The limiting mechanism includes a limiting shaft 5, and the gate plates 3 on both sides are respectively provided with limiting grooves 31 with openings facing each other along the transverse direction. The limiting shaft 5 is arranged transversely and its two ends are respectively located in the limiting grooves 31 of the gate plates 3 on different sides. When the lower end of the gate plate 3 tilts inward, the limiting shaft 5 is abutted against the groove wall of the limiting groove 31 to form a limiting fit. The limiting shaft 5 located between the limiting grooves 31 of the gate plate 3 is selected. When the lower end of the gate plate 3 has a tendency to tilt inward, the limiting shaft 5 will abut against the groove wall of the limiting groove 31 to prevent the occurrence of tilting, thereby avoiding the gate plate 3 from forming a V-shaped structure.

[0026] It also includes a tension spring 6, which is arranged horizontally. The two ends of the tension spring 6 are respectively located in the limiting groove 31 of the gate plate 3 on different sides and are fixed to the groove wall of the limiting groove 31. Before the valve stem 2 rises, the tension spring 6 can increase the retreat rate and retreat amplitude of the gate plate 3 to the inside, rather than relying on the damping between the gate plate 3 and the valve seat 4 for retreat, ensuring that the gate plate is in a non-contact state with the valve seat 4 before rising, avoiding wear and tear between the two during the rising process, extending the service life, and ensuring sealing performance.

[0027] The groove wall of the limiting groove 31 corresponds to the end of the tension spring 6 and is surrounded by a mounting boss 311. The inner side surface of the mounting boss 311 and the tension spring 6 form a threaded fit to fix the two. The limiting groove 31 and the tension spring 6 are fixed by threaded fit, which improves the convenience of disassembly, assembly and maintenance.

[0028] Limiting bosses 51 are respectively arranged around both ends of the limiting shaft 5, and a telescopic gap 52 corresponding to the position of the tension spring 6 is formed between the limiting bosses 51 at both ends. The tension spring 6 is fixed to one of the limiting bosses 51, and a telescopic gap is formed between the limiting bosses 51, so that the tension spring 6 can minimize the contact with the limiting pin during the telescopic process, that is, reduce wear, thereby extending the service life and reducing the opening and closing damping.

[0029] The tension spring 6 and the limiting boss 51 are fixed by welding. The welding fixing method has good fixing reliability and a small fixing area, and is more suitable for fixing the tension spring 6 and the limiting boss 51. Point a in the figure is the welding point.

[0030] The transverse movement mechanism includes a wedge block 7 and a wedge matching block 8 in a wedge-shaped fit. The wedge block 7 is located at the lower end of the valve stem 2. There are two wedge matching blocks 8, which are located between the gate plates 3 and the wedge blocks 7 on both sides. The wedge block 7 is provided with a mounting hole 71 in the transverse direction. The gate plates 3 on both sides are provided with mounting posts 32 that extend into the mounting holes 71 and move transversely with the mounting holes 71. The mounting posts 32 are hollow and the hollow part serves as a limiting groove 31. A mounting hole 71 for the mounting post 32 to extend into is provided on the wedge block 7. The limiting groove 31 is provided on the mounting post 32, so that the limiting groove 31 can be provided near the center of the gate plate 3. Position, improve the limiting effect, a wedge-shaped fitting surface is provided between the wedge block 7 and the wedge-shaped fitting block 8, when the wedge block 7 is in the process of descending, the wedge-shaped fitting block 8 will contact the limiting point 121 at the bottom of the valve cavity 12 first, the wedge block 7 continues to descend, and the wedge-shaped fitting surface squeezes the wedge-shaped fitting block 8, so that the gate 3 moves toward the valve seat 4 until it is sealed and fitted, when the wedge block 7 is in the process of rising, the wedge-shaped fitting surface moves away from the wedge-shaped fitting block 8 to form a retreat space, the above-mentioned tension spring 6 avoids the formation of the retreat space, so that the wedge-shaped fitting block 8 retreats with the wedge-shaped fitting block 8, even if the gate 3 has cancelled the sealing fit with the valve seat 4 before rising.

[0031] In addition, the sealing surfaces between the gate plate 3 and the valve seat 4 can be made of wear-resistant and corrosion-resistant materials, thereby extending the service life under high temperature and high pressure.

Claims

1. A parallel double-disc gate valve, comprising a valve body, a valve stem, a gate, and a valve seat. The valve body is provided with a flow channel for fluid to pass through and a valve cavity located in the middle of the flow channel for the gate to be raised and lowered. The gates are located on both sides of the valve cavity and are sealed with a valve seat located at the junction of the flow channel and the valve cavity. The valve stem drives the gate to rise and fall. The valve stem is provided with a transverse movement mechanism that moves the gate laterally toward the valve seat until a sealing engagement is achieved when the gate descends to a position opposite the valve seat. The characteristics of the valve valve are: A limiting mechanism is provided between the gate plates on both sides to prevent the lower ends of the gate plates from tilting inwards when rising; The limiting mechanism includes a limiting shaft, and the gate plates on both sides are respectively provided with limiting grooves with openings facing each other along the transverse direction. The limiting shaft is arranged transversely and its two ends are respectively located in the limiting grooves of the gate plates on different sides. When the lower end of the gate plate tilts inward, the limiting shaft abuts against the wall of the limiting groove to form a limiting fit. It also includes a tension spring, which is arranged in the transverse direction, and the two ends of the tension spring are respectively located in the limiting grooves of the gate plate on different sides and fixed to the groove walls of the limiting grooves; The groove wall of the limiting groove corresponds to the end of the tension spring and is surrounded by a mounting boss, and the inner side surface of the mounting boss is threadedly engaged with the tension spring to fix the two; The two ends of the limiting shaft are respectively surrounded by limiting bosses, and a telescopic gap corresponding to the position of the tension spring is formed between the limiting bosses at both ends, and the tension spring is fixed to one of the limiting bosses.

2. The parallel double-disc gate valve according to claim 1, characterized in that: The tension spring is fixed to the limiting boss by welding.

3. The parallel double-disc gate valve according to claim 1, characterized in that: The transverse movement mechanism includes a wedge block and a wedge matching block in a wedge-shaped fit. The wedge block is located at the lower end of the valve stem. There are two wedge matching blocks, which are respectively located between the gate plates and the wedge blocks on both sides. The wedge block is provided with mounting holes along the transverse direction. The gate plates on both sides are provided with mounting columns that extend into the mounting holes and move transversely with the mounting holes. The mounting columns are hollow and the hollow part serves as a limit groove.

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