Manway cover with integrally formed vent

Abstract

A venting solution to large storage tanks is disclosed wherein a manway cover is formed with a vent, eliminating the need to affix a vent to the wall of the tank and allowing standardized manway covers with different vent sizes to be applied either in a retrofit or in new tanks. The covers can be formed two at a time to increase production, and can be fitted with a larger vent than would otherwise be practical with some tank diameters.

1 . A combination vent and cover for a tank, comprising:
 a circumferential base plate adapted to fit over a port of a tank and seal the tank, the base plate having a bolt hole pattern coinciding with a bolt hole pattern of the tank;   an integral stem formed centrally in the base plate projecting outwardly from the plate;   a vent sized to fit over the stem and connect to the stem, the vent allowing the tank to dispel air as the tank is being filled.   
     
     
         2 . The combination vent and cover for a tank of  claim 1 , further comprising a mushroom cap for the vent. 
     
     
         3 . The combination vent and cover for a tank of  claim 1 , further including a removable flange about the base of the vent for allowing the vent to attach to other tank configurations. 
     
     
         4 . A double molded manway cover for a tank having a first cover molded to a second cover, each cover having a circumferential base plate adapted to fit over a port of a tank, and an integral stem formed centrally in the base plate of each manway cover, where both covers are formed in a single molding operation and separated to yield two covers. 
     
     
         5 . The double molded manway cover for a tank of  claim 4  where one manway cover has a larger diameter than a second manway cover. 
     
     
         6 . The double molded manway cover for a tank of  claim 4  where both manway covers have the same diameter. 
     
     
         7 . A tank for storing materials comprising:
 a storage compartment defined by a plurality of surfaces and a conical upper wall with a manway opening;   a manway cover adapted to cover the manway opening, the manway cover including a vent structure for venting the tank when material is forced into the tank.   
     
     
         8 . The tank of  claim 7  wherein the vent structure is a mushroom vent built into the manway cover.