Looking for the proper type of valve to install to bleed pressure off water mains when they have to be taken down for maintenance. The specific instance is a 72" main with a 6" tee and valve piped to open air to release water to drop pressure to zero. The problem I see is with a large volume of water (big pipe at 100psi) moving past a valve as it's opened, it's likely to have some damage to the gate. I see that RW gate valves specifically say 'throttling' is not an intended use. Any suggestions on a readily available municipal water works valve for this application?
eccentric plug valve. This has goood cavitation characteristics. Also it is good for wear as it is used on slurry applications. It will be 2-3 times more expensive than a gate valve. Dezurik make one but I am sure that there are other brands.
Alternatively the tortuous path CCI type boiler let down valve could be used but they are mega bucks. If you have seen this damage before, then avoid that type of valve and a plug valve could be used.  A plug valve will work well for this and should have no difficulty shutting tight.  However, it seems to me that the valve must have been left in a partially open position for quite a while.  It should have been opened fully.

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