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Primary Delta Seal (DLT)

Primary Delta Seal (DLT)

The Primary Delta Seal can be used on external floating roofs or internal floating roofs. This seal design has been used on tanks from 6.0 m. to 91.0 m. in diameter, containing the full range of Crude and Refined products. The design of this joint allows the installation and removal of the latter only from the top of the roof. The effect of the seal between the roof and the tank wall is achieved by the use of trapezoidal sections of special PU foams.

The foam sections are fixed with an adhesive to the internal steel support plate. These plates and the foam blocks are encapsulated in a nylon casing coated with synthetic rubber. The envelope of the seal consists of a fabric covered with a highly abrasion resistant layer which provides a gentle and effective sealing effect. The Delta seal is in contact with the stored liquid, that is why the efficiency of the seal is very high.

For other designs, please head to our Floating Roof Storage Tank Seals page where you can find a range of internal and external tank seals.

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Material Specification:

Two alternative standard envelope materials are generally used:

– Polyurethane Coated Nylon fabric 1.0 mm. thick.

– PVC Nitrile elastomer coated Nylon fabric 1.5 mm. thick.

Service life:

8 – 20 years

Typical weight of complete seal:

20 kg per linear meter

Technical data:

Rim space:

100 mm ± 250 mm (standard)

Aromatic resistance:


Alternative designs and specifications for the Primary Delta Seal (DLT) are available on request

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