User:StoneCreate/Silicone hose

Silicone Hose

Silicone hoses are generally used as an alternative to conventional, organic rubber hoses. They are manufactured for use in a wide range of environments including in vehicles, wind turbines, and generators. Standard silicone hoses are used to connect metal pipe work with other components in systems carrying water and ethylene glycol based coolants. They are frequently used in the coolant systems found inside vehicles such as trucks, buses, cars, and even trains. They can also be used inside generators, and in a wide range of other situations to make connections between rigid or flexible metal pipes.

How They Are Made and Operating Temperatures

Silicone hoses are manufactured from silicone, meta-aramid fabrics and polyester. A lining of fluorosilicone and fluorocarbon is then added to the products to ensure the hoses can perform even under the most severe circumstances, including temperatures of up to 250C. Silicone hoses offer a wider operational temperature range than those created from synthetic rubbers. For example; ethylene acrylic elastomer rubbers such as VAMEC are operational between -60C and +175C, while ethylene propylene diene monomer (EPDM) can operate between -50C and 150C. Our hoses remain flexible at -50C, and can continue performing in extreme temperatures of +250C. Unlike rubber hoses, silicone hoses will not crack, stiffen or fail over time, and so can be relied on even after many years of use. Silicone Hoses are generally hand built using a multi-ply method, this enables them to withstand much higher operational pressures than extruded hoses. Hoses produced using an extrusion method are reinforced using one or two layers of fabric, enabling them to withstand operating pressures of up to 2.5 bar. Using the hand built construction methods, silicone hoses can withstand around 6-8 bar. To achieve this level of durability, silicone hoses have a meta-aramid fabric reinforcement applied over 3, 4 or 5 layers, depending on the specifications required for the hose.

Benefits of Silicone Hose

They will perform over a much wider temperature range than ethylene propylene diene monomer (EPDM), VAMAC, remaining flexible at temperatures as low as - 50⁰C and performing as high as + 250⁰C. They are far less susceptible to heat ageing than organic rubbers. Over time, sustained high temperatures will cause organic rubber hoses to stiffen, crack and fail. Silicone hose will remain virtually unaffected for many years, at normal under bonnet temperatures.

Euro 6 Compliance for Vehicles

January 2015 and January 2016 sees the introduction of Euro VI regulations for newly registered vehicles. In order to comply with the regulations which, primarily call for further reductions in levels of nitrogen oxides and particulate matter, vehicle manufacturers have had to overcome significant challenges in modern engine technology and management.

Higher under bonnet temperatures, higher turbo pressures, increased coolant system pressures and stronger negative pressures in intake systems, are typical problems which have had to be overcome for all of the manufacturers which have to comply with these pending Euro VI regulations. The majority of related companies have had knowledge of these regulations and have been well prepared for the challenges ahead. Working with several major Original Engine (OE) vehicle producers, Manufacturers of silicone hoses have already produced turbo-charger (CAC), coolant and air intake hoses, approved for Euro VI vehicles. Using high quality silicone compounds, and new fabrics capable of withstanding 250⁰C in Charge Air Cooler (CAC) hoses and revised constructions for coolant hoses, both are more than capable of performing reliably on any modern engine. Organic Acid Technology (OAT) resistant and fluorosilicone lined hoses, ensure all potential issues are covered now and well in to the future. Difficult technical challenges have been met in designing a range of air intake hoses. Maintaining a high degree of rigidity to withstand strong, negative pressures while remaining flexible enough to cope with significant movement between air filter and engine, requires a complex construction. All of these requirements need to be met for any silicone hose to be compliant in all Euro VI applications.

Types of Silicone Hose

Organic Acid Technology (OAT) Resistant Hoses Ethylene Glycol coolants usually contain compounds such as amines, phosphates, nitrites, borates and/or silicates. The mixture is far less environmentally friendly than a typical pure OAT coolant mix which usually contains none of the above. Hybrid (HOAT) coolants are generally moderately ‘silicated’ for improved aluminium protection. Ethylene glycol coolants offer rapid protection of cooling system components. However, the inhibitors deplete rapidly meaning that frequent changes of coolant are needed to maintain effectiveness. Typical coolant life can be 30 – 50,000 miles. Pure OAT coolants take longer to protect the metallic components in the system. However, once the protective layer is laid down, the inhibitors deplete only very slowly. Coolant life is typically between 150 – 300,000 miles. The initial cost of OAT coolants is also generally lower than that of ethylene glycol coolant. Cost savings can therefore be significant. Hybrid coolants (HOAT) offer a blend of the two benefits by using a moderate level of salts such as silicates or borates. The HOAT coolants offer rapid protection, long life (150,000 miles) and prevent clogging of water pumps etc. Traditional ethylene glycol coolants have little or no effect on hoses under normal working conditions. However, they can have an effect on certain types of reinforcement fabric used in the hoses.

Straight Hoses - Typically used on radiators within commercial vehicles such as trucks, buses, coaches and tractors. Elbow Hoses - Hoses are usually available in 45 degree, 90 degree, 135 degree and 180 degree angles and are usually found in commercial vehicles to improve the performance of the induction or cooling systems. Reducer Hoses - These hoses are different from the majority of other hoses. These allow a bridge between