Connecting parts brass nickel plated LF 3600 by Legris

Technical Description: LF 3600 Nickel-Plated Brass Connection Fittings

The LF 3600 series from Legris comprises push-in fittings and threaded fittings made of chemically nickel-plated brass, designed for industrial applications and food contact in accordance with FDA and Regulation EC 1935/2004. Core features include precisely machined thread and sealing contours, high corrosion resistance due to the nickel coating, and designs suitable for pressure-bearing pneumatic and fluid lines, as well as for media that come into contact with food processes. The product family covers straight fittings, straight threaded fittings, elbows, and bulkhead fittings, and is compatible with push-in fitting systems.

Material and Surface Properties

The base alloy is brass (CuZn alloy) with a controlled chemical nickel plating. The nickel coating reduces released copper ions, improves sliding properties during assembly, and increases resistance to atmospheric and media-induced corrosion. Material tests for the series consider mechanical strength, nickel adhesion, and compliance with migration-relevant limits according to FDA/EC 1935/2004. Sealing surfaces and internal bores are machined and/or blast-finished to maintain roughness values relevant for sealing function and cleanability in food facilities.

Construction and Designs

The LF 3600 family has a modular design: straight threaded fittings, short and long push-in fittings, 90° and 45° elbows, reduced and double-swivel versions, as well as bulkhead fittings with a nut-side seal. Internal geometries are designed so that the hose or tube is inserted centrally and the clamping/holding zones are evenly loaded. For positive connections, conical sealing cones are used; for friction-locked push-in connections, spring or clamping rings made of stainless spring steel are employed. Thread formats cover metric ISO threads, BSPP/UNF variants, and special hygienic connections.

Seals and Material Selection

Standard sealing is achieved with FKM (Viton) for high temperature and media resistance. Additionally, EPDM and PTFE seals are available when increased resistance to cleaning agents or complete chemical inertness is required. Selection criteria are based on temperature range, permissible cleaning cycles (CIP/SIP), suitability for oil/grease contact, and food conformity. FKM offers durable sealing against many oils, greases, and heating media; EPDM is preferable for aqueous, alkaline cleaning agents; PTFE is used when migration must be minimized.

Connections, Installation Dimensions, and Installation Notes

Thread dimensions and recommended torque values are documented in tables and serve as a guide for assembly. For threaded fittings, the use of a torque wrench is recommended to prevent overtightening of the seal; for push-in fittings, correct insertion depth up to the stop must be ensured to avoid leaks. Bulkhead fittings must be mounted with a flat contact area and a positive-locking nut; for thin-walled bulkheads, a washer or reinforcement is necessary. When assembling in food facilities, tools and sealants must be selected that are safe according to FDA/EC 1935/2004.

Media, Temperature, and Pressure Range

LF 3600 products are tested for air, water, coolants, oil-based media, and certain food components. The permissible operating pressure, depending on the design and connection size, is within the range of typical pneumatic and fluid applications; pressure and temperature ratings are manufacturer-specific and indicated with the product. Typical sealing material combinations allow operating temperatures from -20 °C to +150 °C; higher temperatures are possible with PTFE seals. When used in food production, aggressive cleaning chemicals and high CIP temperatures must be considered, which is why EPDM or PTFE seals are often preferred.

Application Areas and Compliance

Specific fields of application include filling and packaging lines, dosing pumps, cooling circuits in food processing, pneumatic controls for packaging machines, and supply lines in technical areas with food contact. The LF 3600 series meets requirements for food contact components according to FDA and Regulation EC 1935/2004, provided that the respective seal and surface treatment are documented and approved accordingly. For critical applications, a material-specific conformity check, including migration values and cleaning protocol, is recommended.

Practical Examples

Example 1: In a filling plant for liquid foods, nickel-plated LF 3600 push-in fittings are used in the dosing lines. The nickel-coated surface minimizes contact corrosion with aqueous, chloride-containing cleaning media; FKM seals ensure tightness at changing temperatures between cleaning cycles. Assembly: Insert the hose until it stops, visually inspect the sealing lip, tighten to the manufacturer's specified torque.

Example 2: In a packaging machine, LF 3600 series elbows replace previous plastic elbows to achieve higher mechanical strength at impact points. The use of a bulkhead fitting allows for easy installation through the machine bed, with the bulkhead thickness reinforced by a support plate. Result: reduced maintenance intervals and stable pressure conditions during rapid switching cycles.

Example 3: In cooling circuits of food production, straight threaded fittings are used to absorb temperature deviations and stresses in pipelines. Combination with PTFE seals reduces contamination risks at elevated CIP temperatures. Regular inspection of seals and retightening after initial operating hours ensures long-term tightness.

Maintenance, Testing, and Cleaning Recommendations

Regular visual inspection for corrosion, damage, and play is standard. Seals should be checked during each disassembly and replaced if visible aging or hardening occurs. Cleaning protocols in food facilities must document cleaning chemicals, temperatures, and contact times; LF 3600 materials are compatible with common CIP/SIP processes, provided the seal combination is suitable. For pressure testing after assembly, standardized test pressures and time intervals must be observed; leak rate and seal deformation should be recorded.

Compatibility and Spare Parts

LF 3600 push-in fittings are compatible with standard push-in tubes and hoses; when using special profiles, check the nominal sizes and receiving geometries. Replacement seals and retaining springs are available as service kits. Technical drawings, assembly instructions, and material certificates can be found in the product documentation or via technical information pages such as https://maku-industrie.de/technik. Specific application examples are available at https://maku-industrie.de/anwendungsbeispiele.

• Available sealing materials: FKM, EPDM, PTFE; Connections: metric threads, BSPP, bulkhead fittings; Designs: straight, 45°/90° elbows, reduced versions.

Selection Aid and Ordering Information

Select the connection type according to the installation situation (threaded fitting vs. bulkhead mounting), sealing material according to the cleaning and media profile, and surface treatment (nickel-plated) for increased corrosion requirements. Observe specific manufacturer information on maximum operating pressure, tightening torques, and temperature limits. For questions regarding practical selection or validation of your system configuration, use the technical resources or contact support via the product page.

FAQ

1. Are LF 3600 connections suitable for CIP/SIP processes?

Yes, if the chosen seal (EPDM or PTFE preferred) and surface treatment are documented to withstand CIP/SIP conditions; FKM has limited applicability with very alkaline cleaners or high CIP temperatures. Check the manufacturer-specific documents for temperature and chemical resistance.

2. What advantages does chemical nickel plating offer over uncoated brass?

Nickel plating reduces released copper ions, increases corrosion and wear resistance, improves sliding properties during assembly, and facilitates cleanability through smoother surfaces. It is particularly advantageous in moist, chloride-containing, or hygienically sensitive environments.

3. How do I determine the correct seal for my application?

Refer to the temperature range, medium (water-based, oil- or grease-based, cleaning agents), CIP/SIP frequency, and migration behavior requirements. Use FKM for high media and temperature resistance, EPDM for aqueous/alkaline cleaning environments, and PTFE when maximum chemical resistance and minimal migration are required. If in doubt, check material data and confirm the selection with an operational approval.