Connecting parts brass nickel plated LF 3600 by Legris

Technical Overview: Nickel-Plated Brass Fittings LF 3600

The LF 3600 series from Legris comprises push-in fittings and threaded fittings made of chemically nickel-plated brass, designed for use in industrial and food processing applications. Products in this category offer corrosion protection, improved sliding properties, and high mechanical resistance while complying with food regulations (FDA, Regulation (EC) No. 1935/2004). Typical components include straight and angled push-in connectors, bulkhead and threaded fittings, and multifunctional connectors for pneumatic and fluid systems.

Material Requirements and Coating

The base alloy is brass (Cu-Zn), which receives a thin, homogeneous nickel surface through chemical nickel plating. This layer reduces friction loads during insertion, increases wear resistance, and improves resistance to tarnishing in humid environments. Material characteristics such as tensile strength, fatigue strength, and machinability meet industrial requirements for connection parts. In contact with food, the combination of brass substrate and nickel plating is designed to keep metal migration within the limits specified by FDA and 1935/2004/EC regulations. For media-carrying seals, FKM (Viton®) or other FDA-compliant elastomers are typically used, provided the specific product specifies this.

Designs, Connection Types, and Sealing Systems

LF 3600 products cover the following connection principles: push-in mechanism for quick tool-free assembly, threaded connections for fixed static connections, and bulkhead fittings for feed-throughs in housing or container walls. Seals are designed depending on the material and medium; FKM seals are standardly recommended for oils, greases, and many cleaning chemicals, while EPDM or NBR may be suitable for aqueous media and steam disinfection. The sealing interfaces are designed to withstand axial and radial loads and show no significant pressure or media diffusion during repeated insertion.

Performance Parameters and Test Criteria

Key performance indicators include leak-tightness at specified pressures, tensile and pull-out loads of the push-in connections, temperature resistance of the sealing materials, and corrosion resistance of the nickel plating. Typical tests include pressure tests (hydraulic and pneumatic), endurance tests with cyclic insertion cycles, and media compatibility tests according to relevant food standards. Nickel-plated brass components of the LF 3600 series must be selected for operating pressures and temperatures that vary depending on the seal choice and geometry; technical data sheets for individual products contain precise information on maximum operating pressure, temperature range, and recommended operating media.

Application Scenarios in Industry and Food Sector

In industrial environments, LF 3600 connections are frequently used in pneumatic control circuits, compressed air networks, cooling systems, and in applications with hydraulic-like fluids where metallic connection elements require mechanical robustness and long service life. In the food sector, the connectors are used for lines carrying liquid ingredients, rinsing systems (CIP/SIP-supported pipelines), and for areas where food contact is possible. The nickel-plated surface allows for easier cleaning processes and reduces the adhesion of deposits, which supports process hygiene.

Practical Examples

Example 1 — Liquid Food Filling Plant: In a filling line, LF 3600 threaded fittings are used to connect the filling hoses to the valve block. Seals: FKM for compatibility with oil-containing flavorings. Assembly: Threading with torque according to data sheet, followed by a pressure test protocol at 1.5× operating pressure. Result: No leaks during continuous operation, easy disassembly for maintenance.

Example 2 — Pneumatic Control in a Packaging Machine: LF 3600 push-in fittings replace previous plastic fittings on pressure-loaded actuators. Advantage: Increased resistance to mechanical loads and higher temperature tolerance during short-term heat cycles. Installation: Push-in connection until an audible click, pull test with a defined force gauge, regular visual inspection of the sealing surface.

Example 3 — Feed-throughs on a Stainless Steel Door (Bulkhead Fittings): LF 3600 bulkhead fitting integrated into a container wall to route a supply line for cleaning and testing technology. Seal: EPDM for resistance to hot cleaning agents. Assembly: Insertion with form-fitting O-ring, tightening of lock nut with specified torque. Function: Damping of vibration loads and hermetic sealing during CIP operation.

Compatibility and Selection Criteria

When selecting, the type of medium, temperature range, operating pressure, insertion cycles, and cleaning and disinfection procedures are decisive. LF 3600 components are compatible with metallic pipelines and flexible hoses, provided that the diameter and hose reception comply with the specification. For aggressive cleaning agents or high chloride loads, additional material evaluations are required; if necessary, alternative materials or coatings must be checked.

Installation, Maintenance, and Inspection Intervals

Correct tightening torque of the threaded fittings prevents overstressing of the seal and ensures recurring leak-tightness. Push-in fittings require regular visual inspection of the sealing surfaces and the groove for foreign bodies. Recommended maintenance intervals are based on operating hours, temperature cycles, and media throughput; documented sample tests after commissioning and periodic pressure tests ensure process integrity. For detailed technical information and operating instructions, please refer to the general technical pages: https://maku-industrie.de/technik.

Compatible Seal Types and Chemical Resistance

FKM (Viton®) offers broad resistance to oils, greases, many solvents, and higher temperatures up to approximately 200 °C for short periods. EPDM is resistant to hot water, steam, and many cleaning agents, but less suitable for organic solvents. NBR is suitable for mineral oils and greases, but shows limitations against ozone and certain cleaning chemicals. The decision for the sealing material is media-dependent and is noted in the specification of the respective LF 3600 part.

Product Variants

• Straight push-in fittings, elbows, threaded fittings, bulkhead fittings — each available in different thread and hose sizes, and with FKM/EPDM/NBR seals.

Regulatory Compliance and Documentation

LF 3600 components are designed to meet the requirements of the FDA (food contact materials) and EU Regulation (EC) No. 1935/2004, provided the specific article number indicates this conformity. Product data sheets and declarations of conformity must be checked for each batch and can be provided upon request. For application examples and specific installation situations, additional documentation is available on our website: https://maku-industrie.de/anwendungsbeispiele.

Procurement Notes

When ordering, the thread type, hose diameter, desired seal, and operating conditions (pressure, temperature, medium) must be specified. Spare part numbers, assembly tools, and maintenance kits are available; their selection reduces possible downtime during maintenance.

Frequently Asked Questions (FAQs)

1. Are LF 3600 connection parts approved for direct food contact?
LF 3600 articles with the corresponding specification are designed for food contact and comply with the requirements of the FDA and Regulation (EC) No. 1935/2004. The approval refers to the specific article material and the seals used; please check the product data sheet and declaration of conformity.

2. Which sealing material is suitable for CIP/SIP cleaning cycles?
For CIP/SIP applications, EPDM is often the preferred choice due to its resistance to hot water and alkaline cleaning agents. In contact with solvents or oily media, FKM is to be preferred. The final selection depends on the cleaning parameters (temperature, pH, duration).

3. How is leak-tightness checked after assembly?
Leak-tightness is usually checked by means of a pressure test: bring the system to 1.25–1.5× nominal operating pressure, check for pressure drop, and visually inspect with leak detection solvents. In addition, repeated insertion/cycle tests and tensile strength tests are recommended to ensure long-term function.