CN204284478U - LNG heavy caliber cast steel stop valve - Google Patents

Abstract

Heavy caliber cast steel stop valve under LNG heavy caliber cast steel stop valve, particularly a kind of LNG ultralow-temperature operation conditions, belongs to valve field.Body cavity adopts the guide structure with guiding rib, and guiding rib is arranged on body cavity; The middle flange of valve gap and valve body joint adopt the combination seal of spirotallic gasket and spring energy-storage ring, and the middle flange of valve gap is fixedly connected with the combination of butterfly spring by stud, nut with valve body; Valve gap adopts long-neck structure, and the upper sealing of valve rod and valve stem seal are arranged in valve gap long-neck, and valve stem seal adopts multi-sealing structure, and arranges disc spring group pretension compensation bit architecture.The connection of flange and sealing reliability during structure of the present utility model ensures, make the leakage point of valve leakage out of steam system reduce to minimum number, valve rod place adopts multi-sealing structure mode to ensure the high-performance sealed requirement of valve rod place zero leakage.

Description

LNG Large Diameter Cast Steel Globe Valve

technical field

The utility model relates to an LNG large-diameter cast steel stop valve, in particular to a large-diameter cast steel stop valve under LNG ultra-low temperature conditions, which belongs to the field of valves.

Background technique

 With the shortage of oil resources in the world, natural gas has attracted more and more attention from countries all over the world due to its abundant reserves. In recent years, due to the uneven distribution of resources, all parts of the world are vigorously developing the LNG storage and transportation industry. LNG/LPG pipelines and transport ships have been constructed on a large scale, and a large number of high value-added ultra-low temperature valves have been used in various projects. In the application of LNG ultra-low temperature valves, the pipeline medium is ultra-low temperature and high pressure liquefied natural gas. This kind of medium is flammable, explosive, and highly toxic. Once it leaks into the external atmosphere, the leakage amount will be multiplied by more than 500 times the volume, which will cause immeasurable and serious consequences to personnel and the surrounding environment. LNG ultra-low temperature large-diameter cast steel globe valve plays a vital role in LNG pipelines. It is necessary to consider the particularity of the valve performance under ultra-low temperature conditions, and to ensure the sealing of the valve no matter at low temperature or normal temperature. performance requirements.

Contents of the invention

In order to solve the above-mentioned problems in the prior art, the utility model provides a large-diameter cast steel stop valve suitable for LNG ultra-low temperature working conditions.

In order to achieve the above purpose, the technical solution adopted by the utility model to solve its technical problems is: LNG large-diameter cast steel globe valve, including valve body, valve disc, valve seat, valve stem and valve cover, and the inner cavity of the valve body adopts a guide valve. Rib guide structure, the guide rib is set on the inner cavity of the valve; the connection between the middle flange of the bonnet and the valve body is sealed by a combination of wound gaskets and spring energy storage rings, and the middle flange of the bonnet and the valve body pass through studs , nuts and disc springs are fixedly connected; the bonnet adopts a long neck structure, the upper seal of the valve stem and the valve stem seal are set in the long neck of the bonnet, the valve stem seal adopts a multiple sealing structure, and the preload compensation of the disc spring group is set. structure. The multiple seal structure includes four sets of seals, which are the first O-ring, the second O-ring, the packing seal, and the elastic energy storage ring; Outside the sealing structure, it is connected and fixed with the valve cover through threads, and welded and fixed into an integrated structure; the preload compensation structure of the disc spring group includes the swing bolt, the disc spring set and the swing nut; the swing bolt and the swing nut fix the disc The spring group and the disc spring group press the multiple sealing structure through the packing pressure plate and the packing pressure sleeve. The long neck structure of the bonnet is provided with a drip plate, which is a two-petal structure, and can be welded and fixed with the bonnet after an appropriate height can be adjusted according to the site conditions. A flat seal is used between the valve flap and the valve seat.

The valve body adopts the structural method of integral casting butt welding connection. The material of the valve body adopts the same material as the chemical composition and mechanical properties of the pipeline material, and is integrated with the pipeline through butt welding connection, which reduces the leakage point of the pipeline connection and ensures the sealing reliability of the overall pipeline. The inner cavity of the valve adopts a guiding structure with inverted ribs. The guide ribs are arranged on three equal positions on the circumference of the inner cavity of the valve, and the guide ribs play a guiding role in the full stroke of the opening and closing of the valve clack, reducing the contact surface between the valve clack and the valve body and the friction force during the opening and closing process.

After adopting the above solution, compared with the prior art, it has the following beneficial effects: the flange in the valve body adopts the sealing form of multiple sealing combinations to ensure the overall sealing performance. The middle flange connection adopts the combined connection method of bolts and disc springs to deal with temperature changes and displacement compensation under elastic creep to ensure the connection and sealing reliability of the middle flange. The bonnet adopts the structural method of integral forging with extended neck, and the upper seal of the valve stem and the valve stem seal are changed from the original separate structure of the bracket and the bonnet to the structure designed in the bonnet, so that the leakage of the valve Leakage points are reduced to a minimum number. The upper seal is set at the position closest to the lower part of the multiple seal structure to prevent the existence of a large amount of low-temperature gas in the bonnet between the upper seal and the multiple seals of the packing. When the volume is enlarged due to temperature changes, there is a local high-pressure area in the bonnet. dangerous accident. The valve stem adopts multiple sealing structures to ensure the high-performance sealing requirements of zero leakage at the valve stem. The disc spring group is used to pre-tighten the displacement and deformation to compensate the change of material deformation caused by temperature change, as well as the change of the deformation of packing and other seals after a long time of work, so as to ensure the sealing performance of the packing seal, so as to achieve High performance sealing requirements with zero leakage at the valve stem. The disc and seat adopt the sealing method of plane seal, which avoids the disadvantages of the conventional cone seal only forming a line seal and the unreliable seal caused by the inconsistent deformation of the seal belt due to the change of high and low temperature, and greatly improves the high and low temperature change and cold resistance. Reliability of sealing under heat alternating conditions. The drip plate can protect the valve body and dissipate heat, and can reduce the overall height of the valve. At the same time, the drip plate is designed as a two-piece structure, which can be fixed in position according to the design requirements before the valve leaves the factory and welded with the valve cover as a whole, or combined and welded after installation on site according to the site conditions. With chain locking device, the switch position of the valve can be fixed at the required position, so as to avoid misoperation of the valve and other influences.

Description of drawings

Figure 1 is a structural diagram of an LNG ultra-low temperature large-diameter cast steel globe valve;

Figure 2 is an enlarged view of LNG ultra-low temperature large-diameter cast steel globe valve I;

Figure 3 is an enlarged view of LNG ultra-low temperature large-diameter cast steel globe valve II;

Fig. 4 is the structural diagram of valve body part;

Fig. 5 is a sectional view of valve body part A-A;

Fig. 6 is a structural diagram of the bonnet part;

Fig. 7 is a structural diagram of the joint between the valve cover and the valve body;

Fig. 8 is a structural diagram of the flat seal between the valve disc and the valve seat.

In the figure: 1. Valve body, 2. Valve disc, 3. Valve seat, 4. Gasket, 5. Valve stem, 6. Disc pressure sleeve, 7. Spring energy storage ring, 8. Stud, 9. Nut , 10. Disc spring , 11. Wound gasket , 12. Rivet , 13. Nameplate , 14. Bonnet , 15. Drip plate , 16. Spring energy storage ring , 17. Packing septum , 18. Packing seal , 19, Packing, 20, spacer, 21, first O-ring, 22, second O-ring, 23, shaft pin, 24, packing gland, 25, swing bolt, 26, packing pressure plate, 27, swing nut , 28. Disc spring group , 29. Pin , 30. Block , 31. Bracket , 32. Needle bearing , 33. Oil cup , 34. Stem nut , 35. Bracket cover , 36. Handwheel , 37. Flat nut , 38, chain , 39, lock head , 40, guide rib , 41, long neck , 42, valve stem seal, 43, upper seal, 44, plane seal.

Detailed ways

In order to gain an in-depth understanding of the structure of the LNG large-diameter cast steel globe valve, the description is as follows in conjunction with Figures 1 to 8:

LNG large-diameter cast steel globe valve, including valve body 1, valve disc 2, valve seat 3, valve stem 5 and valve cover 14, the inner cavity of valve body 1 adopts a guiding structure with guiding ribs 40, and the guiding ribs 40 are arranged on the valve On the inner cavity of the body 1; the connection between the middle flange of the valve cover 14 and the valve body 1 is sealed by the combination of the wound gasket 11 and the spring energy storage ring 7, and the middle flange of the valve cover 14 and the valve body 1 pass through the stud 8, The combination of the nut 9 and the disc spring 10 is fixedly connected; the valve cover 14 adopts a long neck 41 structure, the upper seal 43 of the valve stem 5 and the valve stem seal 42 are arranged in the long neck 41 of the valve cover 14, and the valve stem seal 42 adopts a multiple sealing structure , and set the preload compensation structure of the disc spring group; the plane seal 44 is used between the disc 2 and the valve seat 3. The multiple seal structure includes four sets of seals, which are the first O-ring 21, the second O-ring 22, the packing seal 18, and the elastic energy storage ring 16; the preload compensation structure of the disc spring group is fixed on the bracket 31 , the bracket 31 is set outside the multiple sealing structure, and is connected and fixed with the valve cover 14 through threads, and is welded and fixed into an integrated structure; the preload compensation structure of the disc spring group includes the joint bolt 25, the disc spring group 28 and the joint nut 27 The joint bolt 25 and the joint nut 27 fix the disc spring group 28, and the disc spring group 28 compresses the packing gland 24 through the packing pressure plate 26. The long neck 41 of the valve cover 14 is structurally provided with a drip plate 15, and the drip plate 15 is a two-petal structure.

The valve body adopts the structural method of integral casting butt welding connection. The material of the valve body adopts the same material as the chemical composition and mechanical properties of the pipeline material, and is integrated with the pipeline through butt welding connection, which reduces the leakage point of the pipeline connection and ensures the sealing reliability of the overall pipeline. The inner cavity of the valve adopts a guiding structure with inverted ribs. The guide ribs are arranged on three equal positions on the circumference of the inner cavity of the valve, and the guide ribs play a guiding role in the full stroke of the opening and closing of the valve clack, reducing the contact surface between the valve clack and the valve body and the friction force during the opening and closing process.

The flange of the valve body adopts the sealing form of multiple sealing combinations to ensure the overall sealing performance. The middle flange connection adopts the combined connection method of bolts and disc springs to deal with temperature changes and displacement compensation under elastic creep to ensure the connection and sealing reliability of the middle flange. The bonnet adopts the structural method of integral forging with extended neck, and the seal on the valve stem and the seal at the valve stem are changed from the original separate structure of the bracket and the bonnet to the structure designed in the bonnet to make the valve leak Leakage points are reduced to a minimum number. The upper seal is set at the position closest to the lower part of the multiple seal structure to prevent the existence of a large amount of low-temperature gas in the bonnet between the upper seal and the multiple seals of the packing. When the volume is enlarged due to temperature changes, there is a local high-pressure area in the bonnet. dangerous accident. The valve stem adopts multiple sealing structures to ensure the high-performance sealing requirements of zero leakage at the valve stem. The disc spring group is used to pre-tighten the displacement and deformation to compensate the change of material deformation caused by temperature change, as well as the change of the deformation of packing and other seals after a long time of work, so as to ensure the sealing performance of the packing seal, so as to achieve High performance sealing requirements with zero leakage at the valve stem. The disc and seat adopt the sealing method of plane seal, which avoids the disadvantages of the conventional cone seal only forming a line seal and the unreliable seal caused by the inconsistent deformation of the seal belt due to the change of high and low temperature, and greatly improves the high and low temperature change and cold resistance. Reliability of sealing under heat alternating conditions. The drip plate can protect the valve body and dissipate heat, and can reduce the overall height of the valve. At the same time, the drip plate is designed as a two-piece structure, which can be fixed in position according to the design requirements before the valve leaves the factory and welded with the valve cover as a whole, or combined and welded after installation on site according to the site conditions. With chain locking device, the switch position of the valve can be fixed at the required position, so as to avoid misoperation of the valve and other influences.

Claims (5)

1.LNG heavy caliber cast steel stop valve, comprise valve body (1), flap (2), valve seat (3), valve rod (5) and valve gap (14), it is characterized in that: valve body (1) inner chamber adopts the guide structure with guiding rib (40), and guiding rib (40) is arranged on valve body (1) inner chamber; The middle flange of valve gap (14) and valve body (1) joint adopt the combination seal of spirotallic gasket (11) and spring energy-storage ring (7), and the middle flange of valve gap (14) is fixedly connected with the combination of disc spring (10) by stud (8), nut (9) with valve body (1); Valve gap (14) adopts long-neck (41) structure, and the upper sealing (43) of valve rod (5) and valve stem seal (42) are arranged in valve gap (14) long-neck (41), and valve stem seal (42) adopts multi-sealing structure, and arranges disc spring group pretension collocation structure.

2. LNG heavy caliber cast steel stop valve according to claim 1, is characterized in that: described multi-sealing structure comprises four groups of sealings, is respectively an O type circle (21), the 2nd O type circle (22), packing seal (18), spring energy storage circle (16).

3. LNG heavy caliber cast steel stop valve according to claim 1, it is characterized in that: described disc spring group pretension collocation structure is fixed on support (31), support (31) is enclosed within outside multi-sealing structure, be connected and fixed by screw thread with valve gap (14), and be welded and fixed integral formula structure; Disc spring group pretension collocation structure comprises swing bolt (25), disc spring group (28) and movable joint nut (27); Swing bolt (25), movable joint nut (27) fix disc spring group (28), and disc spring group (28) compresses multi-sealing structure by hold-down grid (26) through filler pressing sleeve (24).

4. LNG heavy caliber cast steel stop valve according to claim 1, is characterized in that: long-neck (41) structure of described valve gap (14) arranges draining board (15), and draining board (15) is two flap-type structures.

5. LNG heavy caliber cast steel stop valve according to claim 1, is characterized in that: adopt plane sealing (44) between described flap (2) and valve seat (3).