John Cole found this on the pipe from the Lava Pump House to the Lava Tank. This coupling changes the pipe from 3" to 4". He's assuming it's a check-valve, but would like to know for sure.
Jason Rose
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El Discípulo de los Viejos Gruñones
RioGrandeExplorations.net
Spring, Texas - MP 209.7 - UP Palestine Sub
"All that is necessary for the triumph of evil is that good men do nothing"
"The price of freedom is eternal vigilance" - Wendell Phillips
"Life is tough, but it's tougher when you're stupid." - Sgt Stryker USMC
"Life is too short to deal with other people's drama. - Sgt Jason Rose USMC