Silicone sleeves are available from Ø 6 to Ø 150, for temperatures up to 275° peak and some configurations can also be resistant to mineral oil.
In particular, Silicone Polyvinylmethylsiloxane (VMQ) is insensitive to temperature changes. It is an excellent electrical insulator and, with appropriate product modifications,...
It solves non-toxicity problems and resolves electrical and thermal conductivity issues. It can operate at operating temperatures from -65° to +200°C.
Some special series reach temperatures of +250°C.
It has good properties in water, when exposed to atmospheric agents, ozone, and UV rays, vegetable and animal oils and glycols.
The SAE J20 standard classifies i flexible hoses for engine cooling systems , intended for use with water and ethylene glycol-based coolants.
The classification includes various types of pipes (identified by "R", such as R1, R2, etc.) and different classes of elastomeric materials (identified by letters, such as Class A, Class B, etc.), each with specific physical properties and resistance. SAE J20 (SAE 20R) Tube Types Main define the tube construction and application:
- SAE J20R1 : Heavy-duty type, available in two wall thicknesses.
- SAE J20R2 : Heavy-duty flexible type with built-in wire reinforcement.
- SAE J20R3 : Normal Duty Heater Hose.
- SAE J20R4 : Normal Duty Radiator Hose.
- SAE J20R5 : Corrugated type with wire backing for normal service.
SAE J20 Material Classes
The classes specify the type of synthetic rubber compound used and its properties, such as temperature and oil resistance:
- Class A : Resistant to high temperatures (e.g. silicone, EPDM).
- Class B : High resistance to oil swelling.
- Class C : Medium resistance to oil swelling.
- Class D-1 : Low oil resistance, improved service.
- Class D-2 : Low oil resistance, standard service.
- Class D-3 : Low oil resistance, high temperature resistance, premium service.
- Class E : Low oil resistance elastomer fiber composite.
Special IDENTIFICATIONS
Additional designators may be added for special features:
- HT: High temperature (for environments above 125°C).
- EC: Electrochemical resistance.
- LT: Extended flexibility at low temperatures (down to -55°C).
In summary, the full designation (e.g. SAE J20 R3 Class A ) identifies a specific heater hose (R3) made from a high temperature resistant material, such as silicone (Class A).