Throttling Capability of Gate Valves 2

[Sawsan311]

Dear All,

I came across that some gate valves design can allow throttling application similar to globe valve, are you aware of any such experience. At the same time, I am worried about the fact that if gate valve is used for control valve selection, in case of failure of the valve, the impact of the fast closing speed (i.e. very small effective valve closing time which is typically 5% of the total valve travel for gate valve) will impose greater risks with respect to surge especially in downstream long pipeline network systems where line packing effects will follow besides the abrupt pressure decline downstream the valve.

Appreciate your views.

regards,

 

[Sawsan311]

Thank you all for the great discussions,

with regards to the bypass across the valve which I was referring to, please note that in light of the fact that for the case of a pumping system, the pump during black start-up will experience high differential pressure across the valve mandating very low Cv requirement. Hence, a bypass can be provided to be exclusively ONLY during that scenario and kept locked in closed position such that it would aid in absorbing the high pressure drop across the valve.

Would that still impose a problem, knowing that discharge inching valve SHALL NOT be used during normal operation for controlling pump's operating point in light of a presence of a VSD motor control system under pressure/flow.

regards,