Silicone rubbers coolant hose

Silicone rubber is well known for its chemical resistance and for its high and low temperature capability. These features have been recognised more recently by certain bus and truck operators who have replaced conventional organic rubber coolant hoses by silicone. A study" into the benefits of silicone hose on the Detroit Street Railway buses resulted in the changeover to silicone hose as far back as 1970. Although not widely used on cars as yet, silicone coolant hose, usually reinforced with polyester or polyamide fabrics, is well accepted for bigger vehicles, particularly those such as buses and trucks where off the road time is expensive and frustrating. Thermostat by-pass hoses are available in the USA made from silicone rubber reinforced with nylon. 

Auto uses are said to account for about one-third of the 30000 tonnes of silicone rubber consumed annually around the world (in turn about 10% of total silicone consumption). Specific uses include shaft sealing rings, spark plug caps, O-rings (the major market for the fluorosilicones), gaskets, coolant and heater hoses for buses and trucks, and ignition cables. 

As a result of its saturated polymer backbone, EPDM is more resistant to oxygen, ozone, UV and heat than the low-cost commodity polydiene rubbers, such as natural rubber (NR), polybutadiene rubber (BR) and styrene-butadiene rubber (SBR). Therefore, the main use of EPD(M) is in outdoor applications, such as automotive sealing systems, window seals and roof sheeting, and in under-the-hood applications, such as coolant hoses. The main drawback of EPDM is its poor resistance to swelling in apolar fluids such as oil, making it inferior to high-performance elastomers, such as fluoro, acrylate and silicone elastomers in that respect. Over the last decade thermoplastic vulcanisates, produced via dynamic vulcanisation of blends of polypropylene (PP) and EPDM, have been commercialised, combining thermoplastic processability with rubber elasticity [8, 9]. 

In addition to the signal and power cables, silicon rubber hoses fixed with aluminum clips were mounted to connect the aluminum cooling lines of the detector mechanics and of the supply tubes. A leak test of the 10 cooling lines of each half detector was performed by filling the lines and monitoring the amount of coolant. No leaks were detected inside the pixel system. 

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