Cushion bottom tank

Claim 1

A liquid storage tank comprising: a vessel having side walls, an inner bottom wall and an outer bottom wall, said inner bottom wall being formed with a discharge member which allows liquid to exit from the tank and with said inner bottom wall sloping towards said discharge member from all side walls, said discharge member being secured to both said inner and outer bottom walls, and with a layer of structural, insulating or vibration dampening material being provided between said inner and outer bottom walls so as to completely fill the space between said inner and outer bottom walls, thus making said inner and outer botom walls integral for superior strength and vibration resistance, said vessel having a generally square cross-section with four side walls which intersect to provide four corners for said tank, said inner bottom wall having a plurality of channels, with one of said channels sloping downwardly from each corner of said tank, said discharge member including a valve flange casting secured to both said inner bottom wall and said outer bottom wall, said flange casting having a valve seal surface, and with said flange casting having means located around the circumference thereof for receiving fasteners for fastening a valve to said flange casting.