Globe Valves in high pressure steam service 2

[boofi]

Good morning y'all,

For many of our HRSG drains and vent lines, the OEM called for globe valves. The HRSG is starting to get up there in age so some of these lines are needing replacement. For some reason the maintenance guy before me stocked our warehouse full of gate valves. Is there any particular reason that globe valves were originally used for the drains and vents? None of these valves are throttled; they're either closed during service or open during maintenance. Is there any other reason to use globe valves over gate in HP steam service?

 

[MJCronin]

HRSG drains and vent valves operate under a large differential pressure. Gate valves will be much more difficult to operate under these conditions. Gate valves are also cheaper ....

Ball valves are also sometimes used....

Properly configured globe valves are less susceptible to extreme erosion and cavitation when they are cracked open than gate valves.

Blowdown and vent valves are sold with special internal trim to ensure long life and mitigate cavitation and erosion

Did your maintenance guy consider any of these important factors when he stocked the warehouse full of gate valves ?

https://www.boilersupplies.com/hanc...hancock-type-55255535-flow-control-valves/214

MJCronin
Sr. Process Engineer

 

[gerhardl]

Already fully and good answered! What experiences do you have with the gatevalves/sealing effect and operation over time? Under circumstances they could be good enough, and even best, as heat recovery often is at fairly low differential pressures and if the system contains firm particle residues.

 

[mk3223]

Could be a safety concern for using globe valve to open slowly the drain and vent for the high temp/press system.