Cryogenic ball valve

Cryogenic ball valve introduction

Cryogenic ball valve is of full size structure. The ball valve has no obstruction at full open position. Cryogenic ball valve body can be made into a one-piece structure, two-piece or three-piece structure to reduce the leakage point.The cryogenic ball valve has top mounted type and side mounted type structure, which can realize online replacement of internal seals.
 
Cryogenic ball valve is suitable for medium temperature -40℃ ~ -196℃,cryogenic ball valve is called low temperature ball valve,which is mainly used for ethylene, liquefied natural gas (LNG) plant, gas LPG, LNG storage tanks to accept base and goonhilly, air separation equipment, oil chemical tail gas separation equipment, liquid oxygen, liquid nitrogen, liquid argon, carbon dioxide cryogenic storage tank and tank lorry, psa oxygen generating device, etc.The output of liquid low-temperature media such as ethylene, liquid oxygen, liquid hydrogen, liquefied natural gas, liquefied petroleum products, not only flammable and explosive, but also in the heating to gasification, gasification, the volume expansion of hundreds of times.
 
Size: 1/2 ~ 24 "(DN15 to 24"))
Pressure grade: 150~1500LB(PN16~PN250)
Connection: Flanged, welded, threaded.
Cryogenic ball valve materials: LCB, LC3, CF8.
Working temperature: LCB(-46℃), LC3(-101℃), CF8 (304) (-196℃).
Applicable medium: liquefied natural gas, ethylene, propylene, etc.
Driving mode: manual,gear, bevel gear, electric,pneumatic.
 

Cryogenic ball valve structure feature

1. Cryogenic ball valve pressure parts material can withstand the media temperature change caused by the expansion, contraction, the structure of the sealing part in the temperature change will not produce permanent deformation.For working conditions below -100℃, ball valve parts should be cryogenic treatment before finishing, put the parts in liquid nitrogen tank for cooling, when the temperature of the parts reaches -196℃, start l-2H insulation, and then take out of the box for natural treatment to room temperature, repeat the cycle for 2 times.
2. Cryogenic ball bonnet with a long neck structure, its purpose is to protect the function of the stuffing box, stuffing box from the low temperature far away from the position, to ensure the sealing effect of the packing.At the same time, it can also wrap the cooling material to prevent the loss of cold energy.The length of the long neck can be selected according to the temperature used and the thickness of the cooling material.When the packing sealing effect is reduced, grease can be added from the middle of the stuffing box to form an oil sealing layer to reduce the differential pressure of the stuffing box and improve the sealing performance.
3. Cryogenic ball valve has to prevent abnormal pressure boost structure, because the low temperature ball valve medium gasification, its volume shock expansion, the pressure will increase abnormally, when the ball valve cavity pressure rises, the ball valve cavity and the inlet side connected, or in the ball valve inlet end of the pressure relief valve, to ensure the safe use of the ball valve.
4. Integral anti-ejecting stem: Meshing with the ball is adopted for cryogenic ball valve, and the stem is fixed in the valve cavity with a large threaded stem sleeve ring with safety positioning screw.
5. Stem sealing: The leak-proof integrity of the ball valve is further enhanced by welding the bonnet design and chevron V-ring sealing, which can be adjusted by simply turning the stem nut.Stem leak-proof seal is achieved by PTFEV ring or graphite filler, the filler is placed on the protruding shoulder matched on the stem to allow the filler and stem to move as an integral unit during the thermal cycle.In addition, the filler is loaded and secured in real time by a self-compensating spring washer and a filler adjusting nut.These features, combined with tight tolerance machining and surface treatment of the fill, allow stem seals to achieve maximum life with minimal maintenance.
 

Cryogenic ball valve working principle

Cryogenic ball valve is suitable for all kinds of pipeline, used to cut off or connect the medium in the pipeline, choose different materials, can be applied to different temperature and medium, the lowest working temperature is -196℃.Low temperature ball valve for manual, worm drive, pneumatic or electric.Low-temperature ball valves are generally flanged, welded and threaded.
Cryogenic ball valve is divided into cryogenic floating ball valves and cryogenic trunnion mounted ball valve. For ball valve with a temperature higher than -50℃, the long-neck structure is generally not adopted. For ball valve with a temperature lower than -50℃, the neck length T is generally 250mm, or determined according to the design and calculation of our company.This product is mainly used for the output of liquid low-temperature media such as air separation equipment, LNG, liquid oxygen, liquid hydrogen, liquefied natural gas, liquefied petroleum, carbon dioxide low temperature storage tank and tank truck, PSA oxygen production equipment. etc.
 

Cryogenic ball valve low temperature test

For the production of cryogenic ball valve developed a strict manufacturing process and the use of special equipment, parts of the processing of strict quality control.After the special low temperature treatment, the rough machined parts are placed in the cooling medium for several hours (2-6 hours) to release the stress, ensure the low temperature performance of the material, ensure the precision machining size, in order to prevent the cryogenic ball valve in low temperature working condition, deformation caused by temperature change and leakage.Cryogenic ball valve assembly and ordinary valve is also different, parts need to be strictly cleaned, remove any grease, to ensure the performance.
Cryogenic ball valve test equipment:
1. Cryogenic valve test device
2. Liquid nitrogen storage device
3. Low temperature treatment tank
4. Low-temperature test bed to ensure the performance of the valve under low-temperature working conditions
5. Other