ATT Tank Mechanical-Shoe Seal (EFR Rim Seal)
Our mechanical shoe seal, also known as a “metallic shoe seal”, is characterized by a metallic sheet (the “shoe”) that is held against the vertical tank wall. Mechanical shoe seal heights typically range from 750 to 1.000 millimeters (mm) or in some occasions even up to 1.300 millimeters (30 to 51 in.). The shoe is connected by braces to the floating deck and is held tightly against the wall by springs or weighted levers. A flexible coated fabric (the “envelope”) is suspended from the shoe seal to the floating deck to form a vapor barrier over the annular space between the deck and the primary seal.
ATT Tank Floating Roof Rim Seals are custom designed to each individual tank within the requirements of API 650/653, BS 2654, EN-14.015 and EEMUA-159.
ATT Tank Continental Tank Serv Engineering has combined over 20 years’ experiences from the past with their research and development, through which it has produced increasingly innovative products for reducing above ground storage tank (AST) emissions.
And it’s not just about the new and interesting, when old technologies and products are to be revitalised or re-used it always can be reviewed and when needed altered to be made more efficient.
Advantages Mechanical-Shoe Seals
The external floating roof rim seal design is such that evaporative losses from the stored liquid are limited to losses from the rim seal system and deck fittings (standing storage loss) and any exposed liquid on the tank walls (withdrawal loss).
Next to preventing vapour losses or preventing ingress of rain water the ATT Tank floating roof rim seals will be provided as the right seal for every type of above ground storage tank (AST).
Due to years of experience in design, manufacturing and installation we as ATT Tank will provide products that satisfy all protection needs.
As recognised by ATT Tank Continental Tank Serv Engineering a competitive, cost effective and good working floating roof rim seal should comply to many basic criteria. Since floating roof rim seal parts are in contact with product, ATT Tank will design these parts as product resistant as possible.
When having a floating roof rim seal mounted in the open, many material parts are subject to UV exposure and will be designed by ATT Tank in UV resistant materials. During the sliding movement against the tank shell all sliding parts will be designed by ATT Tank in wear resistant materials.
While the ATT Tank floating roof rim seals are also designed to positively centre the floating roof, our design will prevent horizontal movements to damage tank features like rolling ladders, gauge poles, pipe drain systems and more. During the horizontal movements of the external floating roof our ATT Tank floating roof rim seals are designed to damp these horizontal roof movements to a minimum. Based on our ATT Tank design input the adequate working range of the floating roof will be analysed and the rim seal designed will be evaluated to comply to the working range needed by the current tank configuration or any local laws or guidelines. This means we can provide each seal with a working range compliant to your request, from API where a range of +/- 4″(102-mm) is required or per EEMUA 159 or NEN-EN 14015 where a tank seal working range of -X/+3X might be requested.
If required, for the secondary rim seals ATT Tank will provide the secondary rim seal exposed material in a configuration, which will meet or exceed any requested fire- retardant level.
In the meantime, ATT Tank will always design any secondary rim as low as possible to allow more filling capacity.
ATT Tank Mechanical-Shoe Seals
The most commonly used ATT Tank Mechanical Shoe Seals either used as a single or combined configuration are:
• MRS-1/750 Primary Mechanical Shoe Seal
• MRS-1/1000 Primary Mechanical Shoe Seal
The MRS-1 models can be combined with
• MRS-12 Secondary Shoe-Mounted Seal
All ATT Tank EFR Rim Seals can be combined with;
• MRS-20S Secondary Compression Plate Seal
• MRS-25 Weather Shield
Last but not least…
When the local requirements are pushing local terminals or refineries to add a tertiare or tertiary or triple rim seal, on request these extra rim seals can be provided by ATT Tank.