Double Seal – 2 Type
The D-Series double seal from ATECO develops the concept of the compression plate secondary seal into a single unit combining the attributes of primary and secondary seals. Commencing from a new tank, the seal may be fitted without extensive welding of clips or attachments to the roof rim plate as is necessary with many other seals. The double seal is fitted solely to the rim plate projection. On retrofit applications, the double seal safely passes over the remaining clips and fasteners previously welded to the roof rim plates as left behind by most primary seals. This minimises the stripping out work when seals are being upgraded.
The D-Series double seal applies compression plate technology to both the primary and the secondary seal elements. Construction is as shown overleaf and it should be noted that an option using a flexible membrane sheet is available with the double seal.
Shell contact is by an extruded polymer tip attached to the upper edge of the secondary seal elements and to the lower edge of the primary seal elements. The polymer will be selected to meet the needs of the particular application and to withstand abrasion from the tank shell and attack from the weather. It is also suitable for use in MTBE service.
The lower, primary element seal tip is normally just above the stored liquid level. For highly volatile products such as gasoline or for dangerous substances such as benzene we recommend the addition of a skirt of light impervious sheeting which is attached to the lower seal tip and, being weighted, droops into the stored liquid. This has the effect of enhancing the sealing efficiency in areas where seal tip to shell contact is less than perfect due to protruding welds, severe corrosion of shell plates etc.
ATECO Tank Engineering seals meet or exceed the allowable gap requirements set forth by the governmental and regulatory agencies throughout the universe. This design will show superior sealing ability throughout the roof travel; accounting for roof shifting, out of roundness, buckling, and the expansion and contraction requirement of each tank.
ATECO TANK warrants its seals to be free from defects in the material and workmanship for a period of two year. Our liability under any express or implied warranty is limited to the purchaser price of any part found defective. Any seal systems installed by ATECO TANK TECHNOLOGY ENGINEERING SERVICE will have an additional two-year warranty.