Rigid PA-hoses by Parker for high pressure ranges

Legirs rigid nylon tubing is manufactured to very close tolerances, to provide consistently high quality over wide temperature and pressure ranges. Our semi-rigid nylon tubing is available in a number of different colours, sizes and lengths to meet your requirements.

1025L - Polyamidee tubings

Polyamidee tubings, length 25 m

Technical Overview of Rigid PA Hoses for High Pressure Ranges

Rigid PA hoses from Parker Legris offer a combination of high pressure resistance, dimensional stability, and chemical resistance. Made from highly compacted polyamide (PA), typically with a Shore D 65 hardness, these hoses are characterized by low creep, tight tolerances, and a long service life in industrial applications. The rigid design ensures defined routing geometries without collapse, reduces vibrations, and allows for precise connection distances in modular machine construction.

Material and Construction

The base materials are polyamide compounds (PA), often PA6 or PA12, thermoplastically extruded and pigmented black for UV and light-induced aging resistance. Due to its higher density and filler selection, PA Shore D 65 achieves pronounced stiffness. The wall thicknesses are dimensioned to ensure pressure absorption and form stability across a wide temperature window. Surface treatments or additives increase abrasion and chemical resistance against coolants, hydraulic oils, and oils based on ester or PAO syntheses.

Pressure and Temperature Behavior

Rigid PA hoses are specified for applications in higher pressure ranges. Typical application areas range from low to medium-high pressures; for exact load limits, product data sheets must be consulted. Temperature resistance depends on the PA type: usual operating ranges are nominally between -40 °C and +80 °C in continuous operation; higher temperatures can be tolerated for short periods. Pressure resistance decreases with increasing temperature; temperature profile and pressure requirement must always be evaluated together.

Connections, Seals, and Compatible Fittings

Rigid PA hoses are supplied as straight versions with a smooth inner wall for push-in systems or with adapted end pieces for screw connections. Compatible connection types include threaded connections (BSP, Metric), quick-release couplings, and crimp or plug-in systems from Parker Legris. For sealing, standard NBR (Buna-N) seals are used; for increased temperature or chemical requirements, FKM/Viton seals or EPDM variants are preferred. The materials and hardness of the seals influence dynamic and static leakage behavior; for cyclic loading, softer elastomers should be avoided to prevent permanent deformation.

Mechanical Properties and Routing Principles

The rigid design allows for tight bending radii without kinking, reduces resonance, and minimizes volume fluctuations during rapid pressure changes. Due to their stiffness, fixed points and brackets must be planned to prevent shear loads at the connections. For moving systems, a combination with more flexible transition lines in a defined transition area is recommended. For static routing, additional line securing is often unnecessary, provided strain relief is provided at the ends.

Chemical and Media Resistance

PA materials exhibit good resistance to oils, fuels, and many coolants; however, strong bases and certain aromatic hydrocarbons can attack the material. Solvent-based cleaning agents, strong acids, or continuous exposure to chlorine-containing media should be checked before use. Test cycles under real media exposure are recommended, especially when used in production processes with varying additives.

Practical Application Examples

Example 1 – Machine Coolant Supply: In a CNC machine tool, a rigid PA hose (straight version, inner diameter 6 mm, Shore D 65) is used for targeted coolant supply to the spindle. Due to its dimensional stability, the exit angle remains constant, increasing tool life through precise coolant jets. Connection is made via an M5 or M6 Parker Legris quick-release coupling; seal: NBR 70 Shore for resistance to coolants.

Example 2 – Pneumatic High-Pressure Supply Line: In an automation module with high switching frequency, a rigid PA hose replaces a flexible line in the pressure line to the cylinder. The reduced volume change and defined routing geometry reduce pressure damping losses during rapid piston movements. Transition connection: BSP adapter to quick coupling; for cyclic loading, an FKM seal is recommended if the ambient temperature rises above 60 °C.

Example 3 – Hydraulic Auxiliary Lines for Tools: In assembly applications with compact hydraulic units, rigid PA hoses serve as short, pressure-stable connecting lines between the valve block and the tool coupling. The smooth inner wall minimizes deposits; the operating pressure of the assembly is dimensioned in advance and compared with the respective data sheet.

Quality Assurance and Standards

Manufacturers like Parker Legris test rigid PA hoses for pressure cycle resistance, aging, and dimensional stability. For industrial applications, protocols for material certificates, batch traceability, and test benches for service life release are relevant. Exact markings on the hose and packaging facilitate reproducibility in spare parts processes.

Selection Criteria for Purchasing

When selecting a product, the following core criteria should be checked:

Operating pressure vs. permissible maximum pressure in the application; consider temperature dependence; compatibility with medium and sealing material.

Additionally, connection types, existing screw connections, dimensionally stable lengths, and mounting options must be considered. For spare parts management, it is recommended to store article numbers and material compositions in the bill of materials and coordinate with supplier contracts.

Practical Notes on Installation

Careful deburring of the connection ends, clean cut surfaces, and precisely fitting insertion depths for quick-release couplings prevent leaks. For crimp connections, the recommended pressing forces and dies must be used. Retaining brackets and strain reliefs reduce shear loads; rigid lines require additional fastening points to prevent vibrations from being transmitted to seals. Before commissioning, pressure tests with defined test pressures and documented test times must be carried out.

Further Information

Details on connection and mounting solutions can be found on our technical page: https://maku-industrie.de/technik. Application examples with practical reports are available at https://maku-industrie.de/anwendungsbeispiele. For product specifications and data sheets, use the respective article view in the shop.

FAQ

1. For which pressure ranges are rigid PA hoses suitable?

Rigid PA hoses are intended for medium-high industrial pressure ranges; the exact permissible operating and test pressures can be found in the respective product data sheet. Operating pressure in conjunction with temperature and medium is crucial.

2. Which sealing materials are compatible?

NBR seals are standard. For higher temperatures or more aggressive media, FKM (Viton) or EPDM are suitable. Selection should be based on chemical compatibility and dynamic loading.

3. How do I correctly install rigid PA hoses to avoid leaks?

Deburr cut edges, adhere to insertion depths and the manufacturer's recommended installation process, use suitable fastening points for strain relief, and perform a pressure test before series operation.