Floating Roof Fabric Seals

Floating Roof Fabric Seals have been developed and tested which are giving excellent service and are making a worthwhile contribution to the industry. They can eliminate the vapour in the rim space by being located at the liquid surface. In effect, the seal fills the vapour space. This feature is particularly desirable with oxygen sensitive or corrosive stocks.

Fabric Seals consist of a fabric band or envelope held against the tank shell by liquid pressure or elastic pressure. The liquid-filled fabric seal entered the market first and has had the longest service life. The elastic or resilient foam fabric seal minimises problems arising from punctures or from localised wear.

Fabric Seals gentle non-abrasive contact protects any corrosion resistant coatings applied to the surface of the tank shell.

A weather shield usually is supplied with Fabric Seals. It is made of overlapped sheets of galvanised steel. Protection from the weather is provided over the rim space even when the top of the floating roof is above the top of the tank shell. Since it is made of metal, the weather shield acts as a shunt for lightning even though the tank shell be coated with a waxy crude oil or paint.

MN-5 Liquid-Filled Seal

The MN-5 Floating Roof Liquid-Filled Fabric Seal consists of two continuous bands of fabric coated with petroleum-resistant synthetic rubber, vulcanised together at their base to form a liquid-tight pocket. The envelope thus formed is filled to a depth of eight or ten inches (203 to 254mm) with sealing liquid, and is positioned within the rim space by a continuous bottom ring. The seal is protected from weather and electrical discharges by the use of a galvanised metal weather shield.

The fabric material is resistant to abrasion and up to 100% aromatics.

The bottom ring is supported by a hanger system. This flexible ring, together with its supports and bumpers, effectively positions the sealing band for good contact with the shell and centres the floating roof within the tank. Since the ring has a fixed circumference, as does the tank shell, it readily adapts to any out of roundness of the tank shell, and maintains a central position in the rim, and permits the seal to be completely effective throughout a rim space variation of ±4 inches (102mm).

MN-7 Resilient Foam Seal

The MN-7 Floating Roof Resilient Foam Fabric Seal uses resilient urethane foam, instead of liquid pressure, to provide the sealing force. This foam is enclosed in a cover made from a special synthetic elastomer coated fabric having excellent resistance to abrasion and up to 100% aromatics.

The MN-7 seal maintains safe, gentle contact even for rim space variations up to plus-or-minus four inches (102mm) from nominal dimension. The advantage of the resilient foam seal is that a puncture or failure of the cover will not cause a sudden failure of the seal and the foam used exhibits high resistance to hydrocarbon and aromatic vapours. Also, when replacement is desirable because of general wear, the work can be performed entirely from above the floating roof.

A galvanised weather shield is normally fitted as standard.

MN-10 Tube Seal

The MN-10 Tube Seal consists of a tough abrasion resistant scuffband and a separate tube filled with liquid. It is mounted on support angles fixed to the roof rim. Both tube and scuffband are supplied in open-ended lengths for ease of installation. Should the tube require to be replaced, this operation can be carried out from the top of the roof.

Depending on the tank conditions the inner tube may be supplied in a series of overlapping lengths.

The MN-10 seal can be engineered to suit a variety of rim gap variations.

The fabric resistance to aromatics is normally 85%, but special fabric can be supplied suitable for 100% aromatics.

A galvanised weather shield is normally fitted as standard.

MN-11 Foam Seal

The MN-11 Foam Seal comprises resilient foam blocks enclosed in a tough polyurethane envelope. Simple hold-down bars are incorporated to prevent the seal from malfunctioning as the roof is raised and lowered. The foam filled envelope remains in close contact with the tank shell at all times, ensuring an efficient sealing system.

The design of this seal allows for rim space variations of ±4 inches (102mm) and permits it to be fitted and removed from the top of the roof.

The fabric is resistant up to 100% aromatics.

A galvanised weather shield is normally fitted as standard.