Natural gas ball valve use and design principle

Natural gas ball valve use and design principle

The use of ball valves in natural gas pipelines is usually a fixed-axis ball valve. Its valve seats usually have two designs, namely the self-vented design of the downstream valve seat and the design of the double-piston effect. Both designs have double-cut seals. The role.

When the valve is closed, the line pressure acts on the outer surface of the upstream seat ring, causing the seat ring to abut the ball. If media leaks into the valve chamber from the upstream seat, when the pressure in the valve chamber exceeds the pressure in the downstream line, the downstream seat will disengage the ball and the pressure in the valve chamber will be released downstream of the valve.

A natural gas ball valve with a double-piston design, under normal conditions, the pressure acts on the outside of the end of the seat ring seal. This force forces the seat ring seal toward the valve body so that it is between the seat ring and the valve body. Form a seal.

If the valve seat leaks, the pressure will directly enter the inside of the valve body. This pressure acts on the inner side of the sealing surface of the valve seat sealing ring and tightly presses the upper part of the valve seat sealing ring. At the same time, this force will force the seat ring seal against the valve body, creating an effective seal between the seat ring and the valve body.

Natural gas ball valves have been increasingly used in modern production and life.

Natural gas ball valve manufacturing specifications

Basic design standards: GB12237, JB/T7745, API 6D, BS5351, ASME B16.34.

Flange standards: ANSI B16.5, MSS-SP44, JB/T79-94, GB9112-9113-88, HG20592-20596.

Welding end standards: ANSI B16.25, GB12224-89 or user requirements.

Structure length standards: GB12221, GB12237, JB/T7745, ASME B16.10, BS5351.

Test pressure standard: API598, API 6D, JB/T13927.

Suitable media: water, steam, liquefied petroleum gas, natural gas and corrosive media, etc.

The pressure-temperature rating of the material is in accordance with GB 9131 or ANSI B 16.5a.

Drive mode: manual, pneumatic, electric, worm gear drive and so on. Natural gas ball valve

material

Part Name

Ordinary carbon steel series

Stainless steel series

Low temperature steel series

Anti-sulfur series

GB standard

NACE standard

Body, left body

WCB

CF8, CF8M, CF3, CF3M

LCB, LCC

WCB

CF8M

Sphere

F6aWCB+HC r

CF8, CF8M, CF3, CF3M

LCB, LCC

WCB+HCrF6a

CF8M

Seat

PTFE; Sintered carbon fiber; Metal + rubber component; Metal surfacing hard alloy

Stem

F6a

304.31 6

F6a

31 8

316

Seat bearing ring

A105 Zn

304.31 6

A105 Zn

A105 Zn

316

Stem packing

PTFE; carbon fiber, flexible graphite

Stem bearings, thrust bearings

Metal lined PTFE; Sintered carbon fiber

Packing ring

F6a

304.31 6

F6a

F6a

316

spring

3Yc-7

Double stud

A193-B7

A1 93-B8, B8M

A320-L7

A193-B7

A193-B7

Nuts

A1 94-2H

A194-8

A194-4

A194-2H

A194-2H

Capping

WCBA105

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