Order compression fittings made of brass by Parker Legris

Order Parker Legris Brass Compression Fittings

Parker Legris brass compression fittings offer a robust, corrosion-resistant connection for pneumatic and medium-pressure hydraulic systems. These fittings are available as straight fittings, tees, elbows, L-fittings, hose barbs, Y-fittings, and cross fittings, covering a wide range of tube variants and operating conditions. The brass used is characterized by good strength, dimensional stability, and high machining quality, making Legris compression fittings particularly suitable for industrial applications in workshops, manufacturing plants, and fluid technology.

Material Properties and Material Use

The brass of Legris fittings is corrosion-resistant to many water and air media and offers better fatigue strength than simple copper alloys. The alloy is chosen to maintain form fit and tightness even after repeated assembly. Contact surfaces and threads are precisely machined to keep torques low and enable repeatable assembly. Depending on the design, seals are used as O-rings made of NBR (nitrile), FKM (Viton), or EPDM; the selection depends on the medium and temperature range. Special sealing materials are available for applications with higher temperatures or chemically aggressive media.

Designs, Connections, and Standards

Legris brass compression fittings are available in various designs: straight male stud fittings with metric or imperial threads, 90° and 45° elbow fittings, adjustable elbow variants (swivel elbow fittings), and T and Y pieces for media distribution. Thread types include BSP/G (ISO 228), NPT for imperial systems, and metric threads according to DIN/ISO. Tube connections are designed as compression rings for rigid and flexible tubes and are characterized by easy assembly without additional tools. Common nominal sizes/dimensions from 4 mm to 25 mm inner or outer diameter are covered; special sizes are available.

Pressure and Temperature Ranges

Typical operating pressures range from vacuum to several bar (medium pressure), depending on the design and tube material. For pneumatic applications, up to 16 bar are often specified; for hydraulic medium-pressure applications, designs up to 25–30 bar are possible. The manufacturer's specifications and the combination with tube material and cross-section are decisive. Temperature resistance depends on the brass and sealing material; standard seals (NBR) typically cover -30 °C to +100 °C, FKM up to +200 °C.

Compatible Tube and Hose Types

Legris compression fittings are designed for various tube types. Suitable are metal tubes (copper, brass, stainless steel), rigid plastic tubes (e.g., PA, PET), and flexible hoses. The choice of the correct compression rings and seals determines the tightness and service life of the connection.

• Common compatible materials: Copper, brass, stainless steel, PA (polyamide), PE, PTFE-coated hoses

Assembly and Maintenance — Precise Practical Instructions

Assembly quality determines tightness and operational safety. Before assembly, cut the tube end at a right angle, deburr, and check for damage. For brass compression fittings, first slide on the nut and compression ring, insert the tube until it stops, tighten the nut hand-tight, and then tighten with a defined torque; for threaded screw-in connections, treat the thread flanks with a suitable sealant (PTFE tape only for suitable thread types). After commissioning, check for leaks and secure again with a defined torque. For reassembly, replace old compression rings, as repeated loosening impairs the clamping effect. Swivel elbow fittings must be aligned so that the sleeve and nut are not overtightened or subjected to localized stress.

Practical Examples and Applications

Example 1 — Pneumatic control line in manufacturing machines: In an assembly plant, 6 mm polyamide lines are connected with Parker Legris brass compression fittings. Tube ends are deburred, compression ring and nut are slid on, the tube is inserted until it stops, and the nut is tightened hand-tight and with a specified torque. After commissioning, the system is checked for leaks. The brass fittings reduce the risk of electrochemical corrosion compared to aluminum connections when using oil-containing compressed air systems.

Example 2 — Medium-pressure hydraulics in test benches: For test systems with pressures up to 20 bar, threaded male stud fittings in brass with FKM O-rings are used. Threads are sealed with PTFE tape, compression ring for tube guidance, connection with torque according to manufacturer. Brass chosen due to good strength and easy rework for assembly changes.

Example 3 — Quick change on assembly lines: Brass elbow fittings and tees enable compact distributions in confined areas. Swivel elbow fittings reduce bending stress on the line, thereby extending the service life of hoses and seals. Maintenance personnel replace defective sealing elements on-site without replacing the entire line.

Selection Criteria and Procurement

Relevant for selection are tube material and diameter, system pressure, medium, temperature range, and thread type. Check the compatibility of the seal with the medium (oil, air, water, gases) and the required temperature resistance. For assembly in potentially explosive atmospheres, special ATEX-compliant versions must be considered. Parker Legris technical data sheets provide information on permissible operating pressures, tolerances, and material codes; compare these with your system requirements. Further technical information and application examples can be found on our pages Technology and Application Examples.

Quality Assurance and Testing Procedures

Before delivery, leak tests and visual inspections should be carried out. During assembly, check the fit and edges of the compression rings and the correct insertion depth. Long-term load tests and temperature cycle tests are useful for critical applications. Markings on the fittings indicate material, manufacturer code, and size; document batch numbers for traceability.

Environment and Recycling

Brass fittings are easily recyclable; during disassembly, dispose of seals separately according to material classes. Prefer reusable assembly practices without reusing damaged compression rings. Pay attention to storage conditions: a dry, corrosion-free environment extends shelf life.

Scope of Delivery and Spare Parts

The scope of delivery typically includes the nut, compression ring, and body. Spare parts include individual compression rings, nuts, and suitable O-rings. For special applications, reinforced compression rings or special sealing materials can also be ordered. When ordering, carefully check size, thread, and sealing material specifications.

Quick Guide for Safe Assembly

Clean and deburr tube, slide on compression ring and nut, insert tube until it stops, tighten nut hand-tight and with defined torque, perform pressure test, if leaking, loosen nut, check tube, replace compression ring.

FAQs

1. Which seals are available for Parker Legris brass compression fittings?

NBR O-rings are used as standard. For higher temperatures or aggressive media, FKM (Viton) and EPDM are available. The selection depends on the medium, temperature range, and chemical resistance.

2. Are Legris brass compression fittings suitable for stainless steel tubes?

Yes. Brass compression fittings can be used with stainless steel tubes. Pay attention to suitable compression ring materials and correct assembly to minimize galvanic effects in humid environments.

3. How often can compression fittings be disassembled and reassembled?

Compression rings are designed for limited repetitions; with each loosening, the compression ring should be checked for damage and replaced if necessary. For critical tightness, replacing the compression ring after disassembly is recommended.