NB 250 isolation valve on suction line

[mechanicaldup]

what is the more economic type of isolation valve to be used on a NB250mm steel line?


I supose a gate valve will be more suitable on a pump suction line?

 

[quark]

You can use either a gate valve or a butterfly valve. A butterfly valve gives you better isolation but it may be redundant in suction line. Further, in open condition, a gate valve gives you the lowest(almost negligible) pressure drop.

 

[mechanicaldup]

what would be the more economic solution quark?