Secondary Seal – Duo Type
Even well designed and properly maintained, primary seals operating in geometrically accurate tank shells permit significant vapour losses from storage tanks. The basic mechanism of loss is due to the swirling, scouring action of the wind. For vapour loss read cash loss. To counter the cash loss, the independently mounted secondary seal of the compression plate type is unequalled. Besides cutting vapour losses, the secondary seal confers other benefits.
The S-Series range of compression plate type secondary seals from ATECO TANK exploits the spring action obtained when custom designed steel plates are compressed to bridge the annular rim gap from tank roof to shell. The plates may be mounted on horizontal or vertical roof rims and made to accept specific bolt pitching. Adjacent compression plates are overlapped, lightly attached and soft gasketed to permit relative movement while presenting an impervious barrier to the passage of vapour. Plates are clamped to the roof rim by channels. As a variant on the above we can provide an option where a flexible vapour barrier is fitted behind the compression plates and the adjacent plates overlap but are not bolted and gasketed. This option is available on request; however, the former details are in our opinion superior for long life and fire safety. Contact with the tank shell is by an extruded S-Series seal polymer tip attached to the upper edge of the compression plates. The form of the extruded tip will be selected from the two styles described below: 1. Single contact: Suitable for butt welded tank shells. High wear resistance. Positive tank shell contact permits removal of waxy deposits. 2. Double contact: Suitable for butt welded tank shells. Lighter contact with shell. Use where shell distorted or very rough, protruding welds, etc. Can be supplied for benzene service. The above are formulated for long life in exposed, arduous conditions.
Available On Request
Fire Protection: note, we can provide access ports in the compression platesfor halon or BCF injection.
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.