Liquefied gas storage tank

Claim 1

A HEAT INSULATED STORAGE TANK FOR STORING LIQUEFIED GAS AT TEMPERATURES BELOW- 40*F. AND AT SUBSTANTIALLY ATMOSPHERIC PRESSURE, HAVING A BASE ADAPTED TO BE FOUNDATION MOUNTED AND HAVING A SIDE WALL EXTENDING ABOVE SAID BASE AND FORMING A CHAMBER OF SUBSTANTIALLY CIRCULAR CROSS SECTION THEREWITH, AND A COVER FOR SAID TANK, SAID COVER BEING SUPPORTED BY AND SEALED WITH RESPECT TO THE SIDE WALL TO FORM A CLOSED PRESSURE TIGHT TANK, SAID COVER BEING OF INVERTED DISHED OR CONICAL SHAPE HAVING ITS APEX PROJECTING INTO THE CLOSED CHAMBER, ONE HALF OF THE APEX ANGLE OF SAID CONE BEING BETWEEN 60 AND 89 DEGREES, SAID COVER HAVING COUNTERWEIGHTS THEREIN TO ESTABLISH A PRELOADING IN THE RANGE OF 10 TO 150 POUNDS PER SQUARE FOOT TO RESIST A PRESSURE BUILD-UP WITHIN THE TANK SUFFICIENT TO DISCHARGE VAPORS RELEASED FROM THE LIQUEFIED GAS, AND A COMPRESSION RING ON THE SAID WALL OF THE TANK ADJACENT THE TOP OF THE SIDE WALL WITH A PORTION INTEGRATED WITH THE COVER AND A PORTION INTEGRATED WITH THE SIDE WALL AND HAVING AN ANNULAR PORTION, SAID COMPRESSION RING RESISTING AND DISTRIBUTING TRANSVERSE AND VERTICAL STRESSES OF SAID COVER TO SAID SIDE WALL.