Cryogenic(Low Temperature) Butterfly Valve

Основные характеристики:

1. Developed For Use In Lng Systems

2. Triple Or Double Offset Design To Reduce Wear On Seat

3. Bi-Directional At Full Pressure Rating

4. Free Access To Stuffing Box And Gland

5. Fire Safe Acc. To API 607

Material Selection:

When selecting materials for use at low temperatures, consider the following two requirements;Enduring ortransient temperature difference stress. Withstand various loads of alternating pressure and temperature, without obvious elastic-plastic deforation. Under ultra-ow temperature conditions, the material should havesufficient organizational stability to ensure tightness;With pressure resislance, wear resistance, corosion resistance and weldabilty.

Cryogenic Treatment:

Austenitic stainless steel as the main pressure part of the ultra-lowtemperature valve is in a metastable state at room temperature. Whenthe temperature is reduced to the phase transition point Ms point, someaustenitic steel will become martensite of body-centered cubic lattice,and the valve seal structure will have a certain deformation. Lower than the valve operating temperature. Cryogenic treatment time of 2-6h, 2-4 times, eliminate the influence ofmaterial phase transition and plastic delormation, ensure the sealing perfomnance of ultra-ow temperature valve.

Long neck valve cover structure:

Prevent frosting or freezing of packing and parts above the valve coverdue to partial undercooling of the packing box. Prevent the inconsistency of low temperature shrinkage of metal andnon-metal materials resulting in increased operating torque of the valveand wear of the packing. The length and dimension of the valve cap neck shall be determinedaccording to the requirements of BS6364 or MSS SP-134 standard;According to the test or user requirements of the method of finiteelement analysis verification.

Long neck valve cover structure:

Set the drip pan to slow down the transmission of the upper end of thevalve body and the packing part of the medium temperature item of thevalve body, and ansure that the tamperature of the upper valve coverand the packing part of the drp pan is above zero.The drip pan and diameter exceed the diameter of the middle flangewhich can prevent low temperature condensation and water vapordripping on the middle flange and bolts, causing cold loss andcorrosion,affecting online maintenance.

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