API 600 and API6 D are different standards for gate valve. Now let us check what's difference between API600 and API6D design for gate valve.
1.Difference of three basic size for gate valve: Valve length, Inside diameter, Flange Size.
|design standard to follow||API 600||API 6D|
|Valve length||ASME B16.10||A table called gate valve face to face and end to end dimensions|
|Inside Diameter||ASME B16.34||A talbe called minimum bore for full opening valve|
|Flange Size||ASME B16.5||ASME B 16.5|
2. Difference of Valve Gate and Valve Seat:
Valve Gate for API 600 Design is Wedge Type and Valve Gate for API 6D design is Slab Type; Valve Seat for API 600 is Inside valve body and is available to move for API 6D. Most Import is API 6D gate Valve is self relieving cavity.
API 600 Gate valve is suitable for high temperature high pressure medium; API 6D gate valve is not suitable for high temperature medium as the O ring is soft meterial.