Discussion on the selection of valves in vacuum sy

2022-08-24
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Discussion on the selection of vacuum system valves

the cold working pressure of this kind of valve should be 600 psi, two-piece cast bronze valve body, Teflon valve seat, standard flow passage, separated packing nut, equipped with adjustable stem packing, anti blow out stem and chrome plated brass/bronze ball. Where pressure drop needs to be concerned, non reducing full port ball valves or valves with similar structures need to be used. The valve connection port shall have American National Standards Institute ANSI thread with sufficient depth, or extended welding port, and shall be manufactured in accordance with MSS-SP110 standard of American valve and pipe fitting manufacturers' Standardization Association

available standard flow passage valves: NIBCO T-ball valve (thread); S-ball valve (welding)

available non reducing full flow valve: NIBCO T-ball valve (thread); S-ball valve (welded)

check valve

check valve with a diameter of less than DN65 should adopt Y-shaped swing structure, and be manufactured in accordance with mss-sp80 standard of American valve and pipe fitting manufacturers' Standardization Association, with a working pressure of 125 pounds, a bronze valve body in accordance with ASTM B 62 standard of American Society for testing and materials, equipped with POLY-4 preferably covered with plastic cloth vinyl fluoride valve seat disc, or a spring driven lift check valve with elastic seat. The valve connection shall be threaded or welded

available valves:

125 LB NIBCO t-413-y check valve (thread); S-413-y (welding)

NIBCO t-480-y spring driven lift check valve (thread); S-480-y (welding)

pipeline control valves with a diameter of more than DN65

butterfly valves

these valves should be lug or international pipeline standard i.p.s. tubular connection port valve bodies, and should be manufactured in accordance with American valve and pipe fitting Manufacturers Standardization Association m such as ss-sp67 standards; The nominal working pressure of DN50 ~ DN300 is 200 psi non impact cold water, and 150 psi above DN350. The valve body used for thermal insulation has a 2-inch extended pipe diameter and is made of cast iron or ductile iron. The butterfly plate is made of electroplated ductile iron or aluminum bronze alloy, equipped with Buna-N valve seat and seal; Or buna-n-coated butterfly plate, equipped with polymer coated valve body. The valve rod should be 400 series stainless steel, and the valve rod should not be exposed on the butterfly plate fasteners. The diameter from DN65 to DN150 should be equipped with an operating handle with 10 position throttle plates; Butterfly valves with a diameter above DN200 should be equipped with gear operators. Lug and tubular butterfly valves should be able to be used as block valves, and can also be used at pipe terminals under full pressure without the need for downstream flanges. Handle operated valves shall be suitable for locking in the open or closed position. Valves that can be used, such as polymer materials, have quite high elongation:

lug valve body, NIBCO LD butterfly valve with plated ductile iron butterfly plate (handle operating mechanism); LD butterfly valve (gear operating mechanism)

lug valve body, NIBCO LD butterfly valve with aluminum bronze butterfly plate (handle operating mechanism); LD butterfly valve (gear operating mechanism)

tubular valve body, NIBCO GD butterfly valve with rubber coated butterfly plate (handle operating mechanism); GD butterfly valve (gear operating mechanism)

check valve

check valve with diameter above DN65 should adopt flat plate (wafer type) structure, and be equipped with stainless steel spring, bronze disc plate and rubber seat. Whether the cast iron valve body that meets ASTM a 126 grade B standard or a 48 standard can reach 250 w/s is the key, and it is equipped with 125 pound or 150 pound flange

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