Thermoplastic hoses
Thermoplastic hoses – general information
Thermoplastic hoses – medium and high pressure hoses made of thermoplastic polymers (most often of polyester, polyamide, polyurethane) with one or two textile or steel wire braids as reinforcement. The reinforcing braids are made of soft textile fibres (polyester as standard, aramid fibres such as Kevlar for high-pressure hoses) or high tensile strength steel wires.
Characteristics and classification of thermoplastic hoses
- very low weight (even up to 60% lighter compared to rubber hose),
- compact structure (small external diameter in proportion to the internal one),
- small bend radius,
- good chemical resistance of an internal layer to hydraulic oil and chemicals,
- very smooth internal layer surface that reduces the loss of flow rate,
- resistance to ageing, ozone and ultraviolet radiation.
- resistance to abrasion of external layer (polyurethane).
When the material of the internal layer is considered, general purpose thermoplastic hoses can be divided into
the following::
material main application other application
polyester hydraulic oil air, gases, fuel, water-based fluids, chemicals
polyamide solvent, paint air, gases, fuel, water-based fluids, chemicals
Standards for thermoplastic hoses
Most hoses in this group are manufactured to specific standards, usually to: SAE J517 (for SAE 100R7 and SAE 100R8 hoses), DIN 24951, ISO 3949 and EN 855. These standards cover two types of hoses: with two textile braids (R7), with two aramid fibre braids (R8) and with constant working pressure (R18).
wąż z podwójnym oplotem tekstylnym (R7)
hose with two aramid fibre braids (R8)
hose with constant working pressure (R18))
typ R7 typ R8 typ R18
Special types of thermoplastic hoses
Non-conductive hoses
wąż termoplastyczny nieprzewodzący
If it is crucial for a hose in a specific application not to convey electric charges, then a non-conductive hose must be used. It is suitable for application near electrical transformers, medium and high-voltage electrical installations. The non-conductive hose has a distinctive orange colour outer layer. The leakage current for non-conductive hoses in test conditions is less than 50 μA at 246 kV/m for 5 min., according to the standard.
Twin and multiple hoses:
wąż termoplastyczny podwójny i wielokrotny
We also offer twin and multiple thermoplastic hoses. A twin version (two hoses with external layers bonded together) is frequently used, e.g. in forklift trucks, hydraulic systems of machine tools or process lines. Multiple hoses consisting of three lines, four lines or more joined together are available on request.
More information on thermoplastic hoses
Pinpricked external layer:
Over longer periods of use, gas particles start to penetrate a hose wall causing blisters or bubbles. Pinpricks – small holes in the outer layer of the hose prevent this process. It is particularly recommended for high pressure gases and hose sections near the fittings. Pinpricking can be performed in the factory or when hose assemblies are produced.
Static electricity:
For some applications, it is important to dissipate electrical charges from a hose (e.g. hoses for paint, organic solvents or when there is high fluid flow velocity). In this case, a hose with a metal braid or an additional conductor (for example, conductive fibres in a braid) must be used, and the fittings must be carefully assembled to maintain the electrical continuity of the hose.
hose with a metal braid
hose with conductive fibres in a braid
hose with a conductive inner layer
hose with a metal braid hose with conductive fibres in a braid hose with a conductive inner layer
Assembly:
Thermoplastic hoses are assembled with Z-type high pressure hose fittings, which are crimped using crimping machines. In some cases M-type crimped fittings or S-type reusable fittings can be used. For ultra high pressure hoses (700 or 800 bar) P-type fittings are used (see HIGH PRESSURE HYDRAULICS – UHP thermoplastic hoses and fittings).