Needle valves vs ball valves in sub-sea control system 1

[mustafa2014]

Dear sirs, Good day,

we are doing a sub-sea project. our company requirements in feed phase to use a needle valve in sub-sea control system.the contractor proposed ball instead of needle.

My question is which better using needle valve or ball valve in sub-sea hydraulic system, what is the main points shall be considered in the selection.
the place of the valves as attached.


Please your feed back highly appreciated

 

[hydtools]

If for isolation as described, then ball valve is sufficient. The valve state is either open or closed. Needle valve would be preferred if some degree of control is required in the valve transition from open to close.

Ted

 

[subsearobot]

Needle valves are also more prone to leakage if over tightened or contaminated. ROV's tend to use brute force, so I'd strongly suggest using a ball valve too.