Stillpipe sealing device

In a tank for storing products that contain volatile substances, which tank is provided with a floating roof with a first opening designed to slide tightly along a vertical stillpipe having a plurality of second openings spaced along the stillpipe for communication between the products in the tank and the inside of the stillpipe;

• a device for reducing the flow of volatile substances from the inside of the stillpipe to the atmosphere through said second openings when such openings are located above the roof the improvement wherein said device comprises a floating body having an outside and an inside and outward sealing means on said outside tightly for engaging the inner circumference of the stillpipe, the volume/weight relationship of the floating body being selected such that the body will float in the product and contains in its inside a portion of the product surface and above the portion of said product surface gas within the stillpipe, the inside of the floating body communicating with the product through at least one third opening and communicating through a fourth opening with the inside of the stillpipe above the floating body to allow the gas pressure in the inside of the floating body to be substantially the same as the gas pressure in the inside of the stillpipe above the floating body, the floating body comprising material that permits direct gauging of the product level with microwaves, said floating body being substantially in the shape of a pipe, downwardly open through said third opening and upwardly open through said fourth opening, said outward sealing means comprising said pipe being provided with a number of annular flexible seals arranged in spaced fashion around the outer circumference of its pipe-shaped outside, said floating body having mounted therein an elongated funnel shaped inner wall terminating at its upper end in said fourth opening and at its lower end in said third opening.

In a tank for storing products that contain volatile substances, which tank is provided with a floating roof with a first opening designed to slide tightly along a vertical stillpipe having a plurality of second openings spaced along the stillpipe for communication between the products in the tank and the inside of the stillpipe;

• a device for reducing the flow of volatile substances from the inside of the stillpipe to the atmosphere through said second openings when such openings are located above the roof the improvement wherein said device comprises a floating body having an outside and an inside and outward sealing means on said outside for tightly engaging the inner circumference of the stillpipe, said sealing means extending in the direction of the axis of said stillpipe for a distance sufficient to seal an adjacent second opening against the flow of volatile substances therethrough the volume/weight relationship of the floating body being selected such that the body will float in the product and contains in its inside an unbroken exposed product surface capable of reflecting microwaves above said contained product surface gas within the stillpipe to permit direct gauging of the product level, the inside of the floating body communicating with the product through at least one third opening and communicating through a fourth opening with the inside of the stillpipe above the floating body to allow the gas pressure in the inside of the floating body to be substantially the same as the gas pressure in the inside of the stillpipe above the floating body, the floating body comprising material that permits direct gauging of the product level with microwaves, said floating body being substantially in the shape of a pipe, downwardly open through said third opening, said inside of said floating body having an inner construction forming a substantially central channel having a cross-section smaller than said third opening, the floating body being arranged in such a way that when floating in said product the product surface is exposed below said channel.