PUR RIM goes under the street.

A proprietary elastomeric rigid foam formulation for polyurethane RIM has been used to produce an under-street valve box (similar to a manhole) to provide access to municipal and residential water lines. Developed by Bayer MaterialScience, Pittsburgh, Bayflex 110-50 RIM system is strong but lightweight, which interested U.S. Foundry & Manufacturing Corp., Medley, Fla. Its engineers were exploring ideas for a new type of valve box, and wanted a highly durable material that would ease the burden of handling and installing these heavy products.

Bayflex 110-50 met the required properties of impact and chemical resistance, stiffness, dimensional stability, and good surface quality. With consultation from Bayer, U.S. Foundry developed the first-ever PUR valve box that is as strong as cast iron at one-tenth the weight. The 15-in.-tall, 20-in.-diam. box weighs only 16 lb and is easy to install with no heavy lifting tools. The box is molded in a 2-min cycle.

The PUR boxes are topped with cast-iron covers. They are typically used in areas that experience light vehicle or pedestrian traffic, such as parking lots, driveways, and lawn areas. In initial testing, U.S. Foundry exposed the box to far more rigorous conditions, positioning it in a location where heavy scrap metal trucks crossed it many times a day. While the concrete around the box crumbled, the PUR kept its integrity without so much as a crack or chip.

The PUR RIM system also enabled designers to reduce the clearance between the box and cover. By acting as an integral gasket, the PUR reduces or eliminates water infiltration. Bayer: [phone] * www.rimmolding.com

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