A low-torque pressure-balanced plug valve

Abstract

The present invention belongs to the field of hydraulic valves, and specifically relates to a low-torque pressure-balanced plug valve, which includes a valve body, a plug, a valve stem, a connecting block, and a threaded seat. The plug is a conical structure with a larger bottom and a smaller top. A fluid passage is provided inside the plug. The plug is rotatably arranged in a valve cavity provided in the valve body, and the valve cavity is divided into an upper valve cavity, a lower valve cavity, and a middle valve cavity. The upper end of the plug is connected to the connecting block, and the threaded seat is installed in the valve body near the upper valve cavity. One end of the valve stem cooperates with the threaded seat and the connecting block respectively, and the other end passes through the valve body and cooperates with the power output end of the drive device. The plug valve can reduce the valve opening torque and provide sufficient valve sealing preload when the medium pressure is low, thereby improving the low-pressure sealing effect of the valve.

Description

Technical Field

[0001] The invention belongs to the field of hydraulic valves, and in particular relates to a low-torque pressure-balanced plug valve. Background Art

[0002] The pressure-balanced plug valve is a special shut-off valve used in long-distance natural gas pipelines and station control systems. It is typically used in harsh working conditions such as natural gas extraction, upstream oil and gas, and mud. It has excellent properties such as long service life, two-way zero leakage, fire and anti-static, and corrosion resistance.

[0003] When the existing pressure-balanced plug valve is closed, the medium in the valve's central cavity flows through the balancing hole at the plug's lower end to the lower valve cavity at the lower end, and then through the side balancing hole at the plug to the upper valve cavity at the upper end. At this point, the lower and upper valve cavities are connected, and the pressures in these cavities are equal. However, because the area of ​​the plug's lower end is larger than its upper end, the medium force F1 acting on the plug's lower end is greater than the force F2 acting on the plug's upper end. Under the influence of the medium pressure, the plug pushes upward, pressing against the valve body's sealing surface, sealing the valve. Because the plug is in close contact with the valve body, the operating force must overcome the frictional force of the plug against the valve body's sealing surface when opening the valve. Consequently, the opening torque of existing pressure-balanced plug valves is relatively high. However, when the medium pressure is low, the difference between the medium force F1 and the force F2 acting on the plug's upper end is less than the weight of the plug, insufficient to push the plug against the valve body, resulting in a poor valve seal. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention provides a low-torque, pressure-balanced plug valve that reduces valve opening torque, facilitating ease of operation. This reduced valve torque allows the selection of a drive device with even lower output torque, reducing valve manufacturing costs. Furthermore, the valve provides sufficient valve seal preload at low media pressures, enhancing the valve's low-pressure sealing performance.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] A low-torque pressure-balanced plug valve, which includes a valve body, a plug, a valve stem, a connecting block and a threaded seat; the plug is a frustum structure with a larger bottom and a smaller top, and a fluid passage is provided inside the plug. The plug is rotatably arranged in a valve cavity provided in the valve body, and cooperates with a valve body sealing surface in the valve body to divide the valve cavity into a valve upper cavity, a valve lower cavity and a valve middle cavity; the upper end of the plug is transmission-connected to the connecting block, and the threaded seat is installed in the valve body near the valve upper cavity, one end of the valve stem cooperates with the threaded seat and the connecting block respectively, and the other end passes through the valve body and cooperates with the power output end of the driving device.

[0007] Preferably, the cross-section of the threaded seat is T-shaped, including a main body and a mounting portion located outside the main body, a trapezoidal threaded hole is provided in the main body to cooperate with the valve stem, and a first inclined surface and a second inclined surface are respectively provided at both ends of the trapezoidal threaded hole.

[0008] Preferably, a connecting installation groove and positioning groove are respectively opened in the valve body near the upper cavity of the valve, the main body cooperates with the positioning groove to realize the installation and positioning of the threaded seat, and the installation part cooperates with the installation groove to install and fix the threaded seat in the valve body.

[0009] Preferably, when the threaded seat is installed and fixed in the valve body, an annular gap is provided between the end of the main body and the bottom of the positioning groove.

[0010] Preferably, a first grease injection channel and a second grease injection channel are respectively provided at the upper end of the valve body near the threaded seat, one end of the first grease injection channel is provided with a first grease injection valve, and the other end leads to the sealing structure of the valve stem; one end of the second grease injection channel is connected with the first grease injection channel, and the other end is connected with the annular gap; when sealing grease is injected into the plug valve through the first grease injection valve, the sealing grease is injected into the sealing structure of the valve stem through the first grease injection channel, and is injected into the interior of the threaded seat through the second grease injection channel, the annular gap and the second inclined surface.

[0011] Preferably, a square groove is provided on the upper end surface of the plug, a transmission groove is provided on the upper side of the connecting block, a square protrusion is provided on the lower side of the connecting block, and a plurality of first springs are evenly arranged in the square protrusions. The first springs are located between the plug and the connecting block, and power is transmitted between the plug and the connecting block through the cooperation of the square groove and the square protrusions.

[0012] Preferably, the valve stem includes a driving part, a first sealing part and a second sealing part arranged in sequence; the driving part cooperates with the power output end of the driving device to drive the valve stem to rotate, and multiple sealing packings and a sealing cover are arranged between the first sealing part and the valve body. One end of the sealing cover is used to compress the multiple sealing packings, and the other end cooperates with the connecting disk arranged at the upper end of the valve body. The second sealing part is provided with a plurality of sealing grooves, and sealing rings are provided in the plurality of sealing grooves.

[0013] Preferably, a trapezoidal thread portion and a transmission portion are further provided on the lower side of the second sealing portion, the trapezoidal thread portion cooperates with the trapezoidal thread hole, the transmission portion has a spherical carbide layer, and the transmission portion abuts against the connecting block after being inserted into the transmission groove; an anti-flying positioning portion is provided between the trapezoidal thread portion and the transmission portion, the outer circumferential diameter of the anti-flying positioning portion is larger than the diameter of the trapezoidal thread portion, and a buffer pad is installed on the anti-flying positioning portion, and when the plug valve is in a closed state, the buffer pad is in contact with the threaded seat.

[0014] Preferably, a spring seat is installed on the lower side of the plug, and a plurality of second springs are arranged in the spring seat. The plurality of second springs are located between the plug and the spring seat and have an initial pre-tightening force. A buffer gap is provided between the plug and the spring seat; a valve cover is installed at the bottom opening of the valve body, and an adjustment pad and an adjustment screw are installed on the valve cover in sequence. A support block is installed on the lower side of the spring seat, and the support block and the adjustment pad abut against each other.

[0015] Preferably, a plurality of first annular grooves are provided at the valve upper cavity of the valve body, a third grease injection channel communicating with the valve upper cavity is provided on the valve body, and a second grease injection valve is provided at one end of the third grease injection channel.

[0016] Compared with the prior art, the low-torque pressure-balanced plug valve provided by the present invention has the following beneficial technical effects:

[0017] 1. The present invention sets a threaded seat in the valve body near the upper cavity of the valve. One end of the valve stem cooperates with the threaded seat, and the other end passes through the valve body and cooperates with the power output end of the drive device. When the valve stem rotates 90° from the closed state to the open state, the valve stem rotates 1 / 4 turn, causing the valve stem to move downward by 1 / 4 pitch and push the plug downward by 1 / 4 pitch. At this time, the plug is separated from the sealing surface of the valve body, and the plug and the valve body rotate without friction, reducing the opening torque of the valve. The above-mentioned setting method can also simplify the setting form of the drive device, so that the valve stem can directly cooperate with the power output end of the existing drive device without setting a complex transmission structure.

[0018] 2. The present invention processes the transmission part of the lower end of the valve stem into a spherical surface after welding a hard alloy layer on the transmission part, thereby ensuring the hardness of the valve stem transmission part and improving the service life of the valve stem. The spherical surface of the transmission part can be automatically aligned with the bottom surface of the transmission groove on the connecting block, preventing the plug from deviating to one side and causing excessive friction of the plug, thereby reducing the opening torque of the valve.

[0019] 3. The present invention provides a grease injection valve and grease injection channel on the valve body. When sealing grease is injected into the valve through the grease injection valve, the sealing grease can be conveniently injected into the sealing structure of the valve stem and the interior of the threaded seat through the grease injection channel. This not only seals the valve stem with grease, but also lubricates the valve stem, reducing friction between the valve stem and the threaded seat during rotation, further reducing the valve opening torque. The threaded seat is positioned within the valve, near the upper chamber, which facilitates the arrangement of the grease injection valve and grease injection channel on the valve body, simplifying the simultaneous sealing and lubrication of the valve stem. Furthermore, the second inclined surface provided on the threaded seat creates an annular gap between the bottom surface of the threaded seat and the valve body, further facilitating the injection of sealing grease into the threaded seat to reduce friction on the valve stem.

[0020] 4. The arrangement of the threaded seat of the present invention also facilitates the arrangement of a buffer pad inside the valve. By arranging an anti-flying positioning portion between the trapezoidal thread portion and the transmission portion of the valve stem, and installing a buffer pad on the anti-flying positioning portion, when the plug valve is in the process of closing, the buffer pad will contact the threaded seat, thereby simply and conveniently reducing the impact on the threaded seat during the valve closing process.

[0021] 5. This invention incorporates a spring seat at the bottom of the plug, with several springs mounted in the spring holes of the spring seat. The buffer gap between the plug and the spring seat provides space for the valve stem to push the plug downward. This provides additional sealing preload when the medium pressure is low, overcoming the weight of the plug and pushing it against the valve body sealing surface, enhancing the low-pressure sealing performance of the plug valve. Furthermore, by providing an adjustment washer and adjustment screw on the valve cover, the initial spring preload can be adjusted to ensure valve sealing. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the low-torque pressure-balanced plug valve of the present invention;

[0023] Figure 2 It is a side view of the low-torque pressure-balanced plug valve of the present invention;

[0024] Figure 3 It is a structural schematic diagram of the low-torque pressure-balanced plug valve of the present invention in a closed state;

[0025] Figure 4 It is a partial schematic diagram of the low-torque pressure-balanced plug valve of the present invention;

[0026] Figure 5 Schematic diagram of the structure of the valve body of the present invention;

[0027] Figure 6 Schematic diagram of the structure of the valve stem of the present invention;

[0028] Figure 7 It is a structural schematic diagram of the threaded seat of the present invention.

[0029] The meanings of the symbols in the figure are as follows:

[0030] 1. Valve body; 2. Connecting plate; 3. Valve cover; 4. Plug; 5. Valve stem; 6. Connecting block; 7. Spring seat; 8. Threaded seat; 11. Valve cavity; 12. Mounting groove; 13. Positioning groove; 14. First ring groove; 15. Second ring groove; 16. First grease injection groove; 17. Valve upper cavity; 18. Valve lower cavity; 19. Valve middle cavity; 20. Valve body sealing surface; 21. Multiple sealing packing; 22. Sealing cover; 41. First balancing hole; 42. Second balancing hole; 43. Second grease injection groove; 51. Drive unit; 52. First sealing unit; 53. Second sealing unit; 54. Trapezoidal thread unit; 5 5. Anti-flying positioning part; 56. Buffer pad; 57. Annular gap; 58. Transmission part; 59. Carbide layer; 61. Transmission groove; 62. First spring; 71. Through hole; 72. Second spring; 73. Support block; 74. Adjustment pad; 75. Adjustment screw; 81. Mounting part; 82. Main body; 83. Trapezoidal threaded hole; 84. First inclined surface; 85. Second inclined surface; 100. First grease injection valve; 101. First grease injection channel; 102. Second grease injection channel; 200. Second grease injection valve; 201. Third grease injection channel; 300. Third grease injection valve; 301. Fourth grease injection channel. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features and technical solutions in the embodiments can be combined with each other.

[0032] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0033] In the description of the present invention, it should be noted that the terms "upper" and "lower" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or the orientations or positional relationships in which the inventive product is typically placed when in use, or the orientations or positional relationships commonly understood by those skilled in the art. Such terms are intended solely to facilitate the description of the present invention and simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" and the like are used solely for distinction and should not be construed as indicating or implying relative importance.

[0034] See attached Figure 1 -Attached Figure 7 As shown, the present invention provides a low-torque pressure-balanced plug valve, which includes a valve body 1, a plug 4, a valve stem 5, a connecting block 6 and a threaded seat 8; the plug 4 is a frustum structure with a larger bottom and a smaller top, and a fluid passage is provided inside the plug 4. The plug 4 is rotatably arranged in a valve cavity 11 provided in the valve body 1, and cooperates with a valve body sealing surface 20 in the valve body 1 to divide the valve cavity 11 into a valve upper cavity 17, a valve lower cavity 18 and a valve middle cavity 19. The upper end of the plug 4 is transmission-connected with the connecting block 6, and a threaded seat 8 is installed in the valve body 1 near the valve upper cavity 17. One end of the valve stem 5 cooperates with the threaded seat 8 and the connecting block 6 respectively, and the other end passes through the valve body 1 and cooperates with the power output end of the driving device.

[0035] In the above embodiment, a threaded seat is provided in the valve body near the upper chamber of the valve, one end of the valve stem cooperates with the threaded seat, and the other end passes through the valve body and cooperates with the power output end of the drive device. When the valve stem rotates 90° from the closed state to the open state, the valve stem rotates 1 / 4 turn, causing the valve stem to move downward by 1 / 4 pitch and push the plug downward by 1 / 4 pitch. At this time, the plug is separated from the sealing surface of the valve body, and the plug and the valve body rotate without friction, reducing the opening torque of the valve. In addition, the above setting method can simplify the setting form of the drive device, so that the valve stem can directly cooperate with the power output end of the existing drive device without setting a complex transmission structure.

[0036] Preferably, the upper end surface of the plug 4 is provided with a square groove, the upper side of the connecting block 6 is provided with a transmission groove 61, and the lower side of the connecting block 6 is provided with a square protrusion. A plurality of first springs 62 are evenly arranged in the square protrusions. The first springs 62 are located between the plug 4 and the connecting block 6. The square groove and the square protrusions cooperate to transmit power between the plug 4 and the connecting block 6. A first balancing hole 41 is provided on the lower side of the plug 4, and the two ends of the first balancing hole 41 are connected to the valve lower chamber 18 and the valve middle chamber 19, respectively. A second balancing hole 42 is provided on the side of the plug 4, and the two ends of the second balancing hole 42 are connected to the valve upper chamber 17 and the valve lower chamber 18, respectively.

[0037] Preferably, the cross-section of the threaded seat 8 is T-shaped, including a main body 82 and a mounting portion 81 located outside the main body 82. A trapezoidal threaded hole 83 that cooperates with the valve stem 5 is provided in the main body 82, and a first inclined surface 84 and a second inclined surface 85 are respectively provided at both ends of the trapezoidal threaded hole 83.

[0038] Preferably, the valve stem 5 includes a driving portion 51, a first sealing portion 52, a second sealing portion 53, a trapezoidal thread portion 54 and a transmission portion 58, which are arranged in sequence. The driving portion 51 cooperates with the power output end of the driving device to drive the valve stem 5 to rotate. Multiple sealing packings 21 and a sealing gland 22 are arranged between the first sealing portion 52 and the valve body 1. One end of the sealing gland 22 is used to compress the multiple sealing packings 21, and the other end cooperates with the connecting disk 2 arranged at the upper end of the valve body 1. Several sealing grooves are provided on the second sealing portion 53, and sealing rings are provided in each of the several sealing grooves. The trapezoidal thread portion 54 cooperates with the trapezoidal thread hole 83 to realize the axial movement of the valve stem 5 during the rotation process. The transmission portion 58 has a spherical carbide layer 59. After the transmission portion 58 is inserted into the transmission groove 61, it abuts against the connecting block 6. In the above embodiment, a hard alloy layer is welded on the transmission part at the lower end of the valve stem and then processed into a spherical surface, thereby ensuring the hardness of the valve stem transmission part and improving the service life of the valve stem. The spherical surface of the transmission part can be automatically aligned with the bottom surface of the transmission groove on the connecting block, preventing the plug from deviating to one side and causing excessive friction of the plug, thereby reducing the opening torque of the valve.

[0039] Preferably, an anti-flying positioning portion 55 is provided between the trapezoidal thread portion 54 and the transmission portion 58. The outer diameter of the anti-flying positioning portion 55 is larger than the diameter of the trapezoidal thread portion 54. A buffer pad 56 is installed on the anti-flying positioning portion 55. When the plug valve is in a closed state, the buffer pad 56 contacts the threaded seat 8 to cushion the impact on the threaded seat 8 caused by the valve closing process.

[0040] Preferably, a connecting mounting groove 12 and positioning groove 13 are respectively formed in the valve body 1 near the valve upper cavity 17. The main body 82 cooperates with the positioning groove 13 to achieve the installation and positioning of the threaded seat 8, and the mounting portion 81 cooperates with the mounting groove 12 to install and secure the threaded seat 8 in the valve body 1. When the threaded seat 8 is installed and secured in the valve body 1, an annular gap 57 is formed between the end of the main body 82 and the bottom of the positioning groove 13.

[0041] Preferably, a first grease injection channel 101 and a second grease injection channel 102 are respectively defined at the upper end of the valve body 1 near the threaded seat 8. A first grease injection valve 100 is provided at one end of the first grease injection channel 101, and the other end leads to the second sealing portion 53 of the valve stem 5. One end of the second grease injection channel 102 communicates with the first grease injection channel 101, and the other end communicates with the annular gap 57. When sealing grease is injected into the valve through the first grease injection valve 100, the sealing grease is injected into the second sealing portion 53 of the valve stem 5 through the first grease injection channel 101, and then into the interior of the threaded seat 8 through the second grease injection channel 102, the annular gap 57, and the second inclined surface 85.

[0042] In the above embodiment, by providing a grease injection valve and grease injection channel on the valve body, when sealing grease is injected into the valve through the grease injection valve, the sealing grease can be conveniently injected into the sealing structure of the valve stem and the interior of the threaded seat through the grease injection channel. This not only seals the valve stem with grease, but also lubricates the valve stem, reducing friction between the valve stem and the threaded seat during rotation, further reducing the valve opening torque. Furthermore, since the threaded seat is positioned within the valve body near the upper chamber, the arrangement of the grease injection valve and grease injection channel on the valve body is facilitated, simplifying the simultaneous sealing and lubrication of the valve stem. Furthermore, the second inclined surface provided on the threaded seat creates an annular gap between the bottom surface of the threaded seat and the valve body, further facilitating the injection of sealing grease into the threaded seat to reduce friction on the valve stem. Furthermore, this arrangement facilitates the installation of a cushioning pad within the valve. By providing an anti-flying positioning portion between the trapezoidal threaded portion of the valve stem and the transmission portion, and attaching the cushioning pad to the anti-flying positioning portion, the cushioning pad contacts the threaded seat during the closing process of the plug valve, thereby simply and conveniently reducing the impact on the threaded seat during valve closing.

[0043] Preferably, a plurality of first annular grooves 14 are provided in the valve upper chamber 17 of the valve body 1, a third grease injection channel 201 is provided on the valve body 1 and is connected to the valve upper chamber 17, and a second grease injection valve 200 is provided at one end of the third grease injection channel 201. By providing a plurality of first annular grooves in the valve upper chamber, when sealing grease is injected into the second grease injection valve, the sealing grease enters the valve upper chamber. Under the action of the medium pressure, the sealing grease can more easily adhere to the valve body sealing surface through the first annular grooves. Secondly, because a first inclined surface is provided on the threaded seat, when sufficient sealing grease is injected into the second grease injection valve, the sealing grease can also be easily injected into the interior of the threaded seat through the first inclined surface to reduce the friction of the valve stem.

[0044] Preferably, a spring seat 7 is mounted on the underside of the plug 4. Several second springs 72 are disposed within the spring seat 7. These second springs 72 are positioned between the plug 4 and the spring seat 7 and exert an initial preload. A buffer gap is defined between the plug 4 and the spring seat 7. A valve cover 3 is mounted at the bottom opening of the valve body 1. An adjustment washer 74 and an adjustment screw 75 are sequentially mounted on the valve cover 3. A support block 73 is mounted on the underside of the spring seat 7, abutting against the adjustment washer 74. A through-hole 71 is formed in the spring seat 7. The valve lower chamber 18 and the valve middle chamber 19 are connected via the first balancing hole 41, the buffer gap, and the through-hole 71.

[0045] In the above embodiment, a spring seat is provided at the bottom of the plug, and several springs are installed in the spring holes of the spring seat. The buffer gap between the plug and the spring seat provides space for the valve stem to push the plug downward. This also provides additional sealing preload when the medium pressure is low. This can overcome the weight of the plug and push the plug tightly against the sealing surface of the valve body, thereby improving the low-pressure sealing effect of the plug valve. Furthermore, by providing an adjustment washer and adjustment screw on the valve cover, the initial preload of the spring can be adjusted to ensure the valve sealing effect.

[0046] Preferably, the lower side of the valve body 1 is provided with a plurality of second annular grooves 15 and a first grease injection groove 16 connected to the plurality of second annular grooves 15. The lower side of the plug 4 is provided with a second grease injection groove 43 corresponding to the first grease injection groove 16. The valve body 1 is provided with a fourth grease injection channel 301 connected to the plurality of second annular grooves 15 and the first grease injection groove 16. A third grease injection valve 300 is provided at one end of the fourth grease injection channel 301. The provision of the grease injection channel and grease injection valve on the lower side of the valve body facilitates the injection of sealing grease into the lower side of the plug, allowing the sealing grease to effectively adhere to the sealing surface of the valve body, thereby ensuring the low-torque characteristics of the valve.

[0047] The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. Although this specification has described the present invention in detail with reference to the above embodiments, the present invention is not limited to the above specific implementation methods. Therefore, any modification or equivalent replacement of the present invention; and all technical solutions and improvements thereof that do not depart from the spirit and scope of the invention are included in the scope of the claims of the present invention.

Claims

1. A low torque pressure balanced plug valve, characterized by: The plug valve comprises a valve body, a plug, a valve stem, a connecting block and a threaded seat; the plug is a frustum structure with a larger bottom and a smaller top, a fluid passage being provided inside the plug, the plug being rotatably arranged in a valve cavity provided in the valve body, and cooperating with a valve body sealing surface in the valve body to divide the valve cavity into a valve upper cavity, a valve lower cavity and a valve middle cavity; the upper end of the plug is transmission-connected to the connecting block, and the threaded seat is installed in the valve body near the valve upper cavity, one end of the valve stem is respectively cooperating with the threaded seat and the connecting block, and the other end passes through the valve body and cooperates with a power output end of a driving device; The threaded seat has a T-shaped cross-section and includes a main body and a mounting portion located outside the main body. A trapezoidal threaded hole is provided in the main body to cooperate with the valve stem, and a first inclined surface and a second inclined surface are provided at both ends of the trapezoidal threaded hole. A connecting mounting groove and a positioning groove are respectively provided in the valve body near the upper valve cavity. The main body cooperates with the positioning groove to realize the installation and positioning of the threaded seat. The mounting portion cooperates with the mounting groove to install and fix the threaded seat in the valve body. When the threaded seat is installed and fixed in the valve body, an annular gap is provided between the end of the main body and the bottom of the positioning groove; A first grease injection channel and a second grease injection channel are respectively provided at the upper end of the valve body near the threaded seat. A first grease injection valve is provided at one end of the first grease injection channel, and the other end leads to the sealing structure of the valve stem; one end of the second grease injection channel is connected to the first grease injection channel, and the other end is connected to the annular gap; when sealing grease is injected into the plug valve through the first grease injection valve, the sealing grease is injected into the sealing structure of the valve stem through the first grease injection channel, and is injected into the interior of the threaded seat through the second grease injection channel, the annular gap and the second inclined surface.

2. The plug valve according to claim 1, wherein: A square groove is provided on the upper end surface of the plug, a transmission groove is provided on the upper side of the connecting block, a square protrusion is provided on the lower side of the connecting block, and a plurality of first springs are evenly arranged in the square protrusions. The first springs are located between the plug and the connecting block, and power is transmitted between the plug and the connecting block through the cooperation of the square groove and the square protrusion.

3. The plug valve according to claim 2, wherein: The valve stem includes a driving part, a first sealing part and a second sealing part which are arranged in sequence; the driving part cooperates with the power output end of the driving device to drive the valve stem to rotate, and multiple sealing packings and a sealing gland are arranged between the first sealing part and the valve body. One end of the sealing gland is used to compress the multiple sealing packings, and the other end cooperates with the connecting disk arranged at the upper end of the valve body. The second sealing part is provided with a plurality of sealing grooves, and sealing rings are arranged in each of the plurality of sealing grooves.

4. The plug valve according to claim 3, wherein: A trapezoidal thread portion and a transmission portion are further provided on the lower side of the second sealing portion. The trapezoidal thread portion cooperates with the trapezoidal threaded hole. The transmission portion has a spherical carbide layer. After the transmission portion is inserted into the transmission groove, it abuts against the connecting block; an anti-flying positioning portion is provided between the trapezoidal thread portion and the transmission portion. The outer circumferential diameter of the anti-flying positioning portion is larger than the diameter of the trapezoidal thread portion. A buffer pad is installed on the anti-flying positioning portion. When the plug valve is in a closed state, the buffer pad contacts the threaded seat.

5. The plug valve according to claim 4, characterized in that: A spring seat is installed on the lower side of the plug, and a plurality of second springs are arranged in the spring seat. The plurality of second springs are located between the plug and the spring seat and have an initial pre-tightening force. A buffer gap is provided between the plug and the spring seat; a valve cover is installed at the bottom opening of the valve body, and an adjustment pad and an adjustment screw are installed on the valve cover in sequence. A support block is installed on the lower side of the spring seat, and the support block and the adjustment pad abut against each other.

6. The plug valve according to claim 5, wherein: A plurality of first annular grooves are provided at the valve upper cavity of the valve body, a third grease injection channel communicating with the valve upper cavity is provided on the valve body, and a second grease injection valve is provided at one end of the third grease injection channel.

Images