hydroturbine penstock headgates

[wbd]

Hello,
I have a problem with the headgates sealing the penstock to dewater for turbine maintenance. An old practice was to drop coal cinders in and they would expand and help seal the leaks around the headgates. We have tried bark mulch with limited success. Does anybody know any thing else that is environmentally friendly, ie any type of grain ?

Thanks for responses in advance

wbd

 

[austim]

wbd

I have heard of sawdust being used to seal leaks between clutches in sheet-piled walls. That could be worth a try (as the computer techos say ).