Abstract Storage tank for a volatile liquid having an outer roof and an internal floating roof, a vent pipe having one end in liquid communication with the bottom space of the tank and the other end extending in vapor communication to outside the tank, means to support the floating roof above the tank bottom and above the liquid when the liquid contents drops below a predetermined level and port means communicating with the vent pipe in close proximity to the bottom of the floating roof for venting vapors from the space below the floating roof to the vent pipe and allowing air or another gas to enter this space from the outside of the tank when the floating roof is supported in nonfloating position above the liquid level. A float can be located in the vent pipe to float on the liquid. The float will be below the port means when the floating roof is not supported by liquid. When the floating roof is supported by the liquid, the float provides a barrier between liquid and vapor in the vent.
In a storage tank for a volatile liquid having an outer roof and an internal floating roof, the improvement comprising: a vent pipe having one end in liquid communication with the bottom space of the tank and the other end extending in vapor communication to outside the tank; means to support the floating roof above the tank bottom and above the liquid when the liquid contents drops below a predetermined level; a vapor vent opening in the vent pipe beneath and in close proximity to the bottom of the floating roof when it is in nonfloating position; and a float in the vent pipe, said float having its peripheral edge in close proximity to the inner surface of the vent pipe.
Claim 2
Dependent Claim
121 words
In a storage tank for a volatile liquid having an outer roof and an internal floating roof, the improvement comprising: a vent pipe having one end in liquid communication with the bottom space of the tank and the other end extending in vapor communication to outside the tank; means to support the floating roof above the tank bottom and above the liquid when the liquid contents drops below a predetermined level; a vapor vent opening in the vent pipe beneath and in close proximity to the bottom of the floating roof when it is in nonfloating position; and a float in the vent pipe, said float having its peripheral edge in close proximity to the inner surface of the vent pipe.
Claim 3
Dependent Claim
26 words
The improvement of claim 1 in which the vent pipe is vertically supported on the tank bottom and extends through the tank to the outside thereof.
Claim 4
Dependent Claim
23 words
The improvement of claim 2 in which the vent pipe has an opening near the bottom of the tank for liquid flow thereto.
Claim 5
Dependent Claim
14 words
The improvement of claim 1 in which the floating roof and float are insulated.
Claim 6
Dependent Claim
30 words
The improvement of claim 1 in which the vent pipe has means to support the float in non-floating position lower than the vapor vent opening but above the tank bottom.