What is Lokring?
Lokring is a mechanical method for producing permanent weld equivalent pipe connections, eliminating the need for hotwork and the associated health and safety issues.
Lokring are patented fittings, they are permanently join small diameter nominal pipe size (1/4 thru 3) and tube (1/4″ thru 2″) without threading or welding.
Following insertion of the pipe or tube end into the fitting, hydraulic tooling is used to advance each swage ring axially over the fitting body, radially compressing (swaging) the fitting body on to the outside diameter of the pipe or tube.
Patented Elastic Strain Preload (ESP®) technology
The leak-free seal is the result of LOKRING’s ESP installation where the axial movement of the LOKRING driver over the body swages the body onto the pipe’s surface. This compresses the pipe wall first elastically and then plastically.
The pipe wall resists this swaging action, generating high unit compressive loads at the contact points between narrow sealing lands inside the fitting body and the pipe surface.
These contact stresses are sufficiently high to plastically yield the tube surface under the sealing lands, forming a 360° circumferential, permanent, metal-to-metal seal between the pipe and fitting body. The driver, which experiences a small increase in diameter (elastic strain) during installation, exerts an elastic, radial pre-load on the metallic seals for the use of the connection.
LOKRING meets or exceeds the following technical specifications, standards and approvals:
- ISO 9001:2008
- Lloyd’s Register #98/00070 and #10/60002
- Canadian Registration Number (CRN): OA1195
- British Ministry of Defence
- American Petroleum Institute – API-607 Rev 4 Fire Test
- ASTM-F1387 NAVSEA
- ANSI/ASME B31.1, B31.3, B31.4, B31.5, B31.8, and B31.9
- Association of American Railroads (AAR)
- United States Coast Guard
- National Fire Protection Association, standard for health care facilities (NFPA 99)
- Canadian Standards Association (CSA) Z7396 1-09
- California Air Resources Board (CARB)
- American Bureau of Shipping (ABS)
- The handling, installation and inspection of LOKRING™ fittings should be carried out only by qualified trained personnel. The LOKRING Installation Procedure provides the instruction and procedures necessary to qualify an individual as a trained LOKRING installer.
- Three different sources of hydraulic power may be used to install LOKRING fittings. Manual, electric (110 Volt or battery), and pneumatic pumps are available from a number of manufacturers through LOKRING or direct. All pumps must be single acting, automatic dump, with a 10,000 psi rating. When supplied by LOKRING these pumps come equipped with quick disconnect hydraulic fittings that mate to hydraulic hose and LOKTOOLS supplied by LOKRING.
Examples Pressure Rating for Stainless Steel Pipe Fittings:
- NPS 1/2 Schedule 80 = 4760 Psi / 328 bar (ASME B31.1)
- NPS 1/2 Schedule 80 = 5060 Psi / 349 bar (ASME B31.3)
- Maximum design pressure given for temperatures from -60° to 100°F for ASME B31.1, and from -325° to 100°F for ASME B31.3.
Lokring products can bring significant benefits in both new installations and maintenance applications, enabling pipework installations up to 70% faster and cost saving of up to 70% compared to welding.
Source April 22, 2014: www.lokring.com