Heat protection

Glass fiber hoses for heat protection: Variants and applications

To ensure optimized heat protection, GREMCO manufactures glass fiber hoses for temperature-sensitive applications such as coolant hoses or brake and fuel lines. For this purpose, we produce our glass fiber hoses with different coatings depending on the application. These are primarily used within applications in the automotive industry. They can be divided into two areas. These are:

– Thermal protection hoses

– Reflective heat protection tubes

Glass fiber hoses for thermal heat protection

Thermal protection hoses are heat protection hoses for thermal insulation during heat convection.  These are braided fiberglass sleeves impregnated with various resins, mostly silicone-based. The high-temperature resistance of the glass fiber is limited by the respective resin. Thus, the selection of the resin to be used depends on the respective application area within an automobile. The resin is used to increase the mechanical strength of the glass fiber. In addition to the braided standard tubes with individual expansion rates, there is a version with a cross-ribbed structure, which offers additional mechanical strength as well as enabling a higher deltaT utilizing an additional air gap. Furthermore, the two previous hoses can be combined into a so-called “double sleeve”. In this case, a standard hose is pulled over a cross-ribbed hose on the outside, which creates an additional air gap that further improves the deltaT.

Our fire protection hose “Fire Shield” is a special kind of heat protection hose. This protective hose is based on a carrier material made of textured glass fiber and has a thick silicone rubber coating. This enables the functional integrity of the application unit to be protected against open flame for a pre-defined period, depending on the specification.

Glass fiber hoses for reflective heat protection

On the other hand, reflective heat protection products primarily serve to protect against radiant heat. All these products are laminated on the outside with aluminum foil in various thicknesses to achieve the reflective effect. With the heat protection hoses, three variants can be differentiated. These are the flat hose based on pure glass fiber, which is available endlessly on a reel, a stable, round and flexible version, and a self-retracting wrap version for subsequent installation, which is sealed with aluminum tape. In all versions, the carrier material is made of glass fiber. The latter two, round versions also have polyester monofilaments, which give the construction the necessary stability. This means that the material always returns to its original shape even when pressure is applied.

Besides reflective heat protection tubes, we also design 3-dimensional solutions for geometric structures. The basis is that of flat fabric with sealed ends to prevent fraying and to meet residual dirt requirements. The resulting 3-dimensional shape can be closed with aluminum tape or high-quality snap fasteners as required. These meet the extremely high requirements of the American automotive market for closing and opening forces.

Application areas

One of the classic applications for thermal heat protection glass fiber hoses is exhaust gas recirculation (EGR/EGR). This is thermal insulation to maintain the temperature in the system. At present, the first applications of the hoses in the field of electromobility for the protection of coolant lines from liquid metal droplets are being developed.

Today, the fire protection hose “Fire Shield” is used to protect battery lines and cables in the field of electromobility in case of a thermal runaway. Traditional applications are found in heavy metal processing or aviation for the protection of hydraulic lines.

Reflective heat protection hoses with aluminum coating are mainly installed on assemblies in the automotive industry at critical temperature ranges due to heat sources, for example in the engine compartment or near the exhaust tract. This can include protection for air-fluid systems and their connectors, individual solutions for geometric components, electrical lines, and cables and their connectors, or mechanical actuation cables such as handbrake cables.