Alfa Laval tank cleaning machine gets threaded onto the bottom 2 in. NPT Male Inlet. The adapter is then placed through the top of the manway opening and lowered into the tank. The cone-shapped "stopper" will retain the cleaning spray inside the tank and prevent burns to the personnel (caused by hot water or caustic solutions), prevent short circuits to exposed electrical equipment and prevent the accumulation of ice when used in cold climates.