MRS-70 Secondary Wiper Seal

MRS-70 Secondary Wiper Seal

Maxwell MRS-70 Secondary Wiper Seal (IFR Rim Seal)

Our MRS-70 Secondary Wiper Seal is a vapor or vapour mounted rim seals on an internal floating roof consists of a continuous seal mounted on the rim of the floating roof and extending to the tank wall, covering the entire primary seal. Our secondary wiper seals consist of a continuous annular blade of flexible material fastened to a ricer bracket mounted on the deck perimeter above the primary seal, which spans the annular rim space and contacts the tank shell. The mounting is such that the blade is flexed, and its elasticity provides a sealing pressure against the tank shell. Such seals are vapor-mounted; a vapor space exists between the liquid stock and the bottom of the seal. For emission control, it is important that the mounting be vapor-tight, that the seal extend around the circumference of the roof, and that the blade be in substantial contact with the tank shell.


Some different types of materials are used to make the wipers. One type consists of a cellular, elastomeric material tapered in cross section with the thicker portion at the mounting.

Rubber is another used material. All radial joints in the blade are joined. A second type of wiper seal construction uses a foam core wrapped with a coated fabric. Polyurethane on nylon fabric and polyurethane foam are common materials. The core provides the flexibility and support, while the fabric provides the vapor barrier and wear surface.


Maxwell 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.

Maxwell 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.


The most commonly used Maxwell Vapor Mounted Seals or vapour mounted seals either used as a single or combined configuration are:

• MRS-60 Primary Wiper Seal


All Maxwell EFR Rim Seals can be combined with;

• MRS-70 Secondary Wiper Seal


Finally, 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 Maxwell.