The patented LOKRING® tube connection system provides an innovative system of braze-free tube connectors for every installation situation in refrigeration and air conditioning technology.

Areas of Application

Row of industrial air conditioners on a roof with patterns on the surfaces in the background, partly cloudy sky

A/C System

(split, multi-split, VRV/VRF)

A range of refrigerators and freezers

Commercial Product Refrigeration

Technical room with industrial equipment such as pipes, tanks, and control elements, well lit and tidy with black ceiling and wall pipes as well as colored valves and displays

Heat Pumps

Close-up of solar panels with sunlight reflections on the surface arranged in rows with light and shadow patterns

Solar Thermal Energy

Series of closed cylinders

Geothermal Energy

Mechanical component with two copper pipes connected by a central metal coupling made of brass and steel

Advantages vs Brazing

  • 40% up to 60% time saving
  • More simple
  • More reliable
  • Cleaner
  • No nitrogen necessary
  • No heavy equipment
  • No fire protection
  • Installations during business hours
  • No fire license necessary
  • More cost effective

Material Combinations

Material combinations, various short metal tubes
Material combinations, various short metal tubes

Functional Principle

THE TYPICAL LOKRING union joint consists of two LOKRINGs and one tubular joint for the acceptance of the two tube ends. Thanks to the conical inner contour of the LOKRING and the special outer contour of the joint, the diameter of the connection is reduced during assembly to such an extent that the joint and the tube create a hermetically sealed metal-to-metal connection. The lifetime gas-tightness of the fitted connection is ensured by the state of permanent elastic pretension, which is produced by the radial forces of the LOKRINGs acting in the opposite direction to the tube-joint connection.

Copper pipe with brass connection in the middle, secured by two blue clamps on the sides
Metal tube with grooves, centrally positioned slide with green components

Lokring Brass Connectors

LOKRING Aluminium Connectors

LOKTRACER Tracer Gas Leak Detection

Technical Information

Approvals TÜV / UL (File SA12004)
Reference standards EN 378-2 and ISO 14903
Max. operating pressure 75 bar (1088 psi)
Admissible refrigerants HFC, HC, HFO, CO2 (unterkritisch) / not suitable for NH3
Temperature range -50°C up to 150°C (-58°F bis 302°F)
Tube diameter range 6 mm up to 41.3 mm (1/4" bis 1 5/8")
Minimum tube wall thickness 0.7 mm

The German standard of quality management is the benchmark for the international production of LOKRING. The certified quality management and the deployment of highly advanced industrial image processing systems facilitate 100% quality control.

Sustainability

Since our tube connections are hermetically sealed, we can ensure that no climate damaging refrigerants leak into the environment. Furthermore, LOKRING makes the use of environmental friendly but flammable refrigerants (HC) safer and allows the use of CO2 (R744). Thus, by using LOKRING tube connections you make a contribution to the active protection of the environment.