Lok-Ring® Joint Ductile Iron Pipe

ACIPCO Lok-Ring Joint Ductile Iron pipe, utilizing the sealing features of the time-proven Fastite Joint and an essentially boltless restrained connection, provides an easily assembled positive restraint against endwise separation due to thrust resulting from internal pressure or external forces. Only a minimum of time is required to complete the Lok-Ring installation.

The patented Lok-Ring Joint* is designed for a working pressure up to 25 Bars for 350mm - 700mm, and 16 Bars for 800mm - 1600mm.** An alloy steel welded-on ring and a split Lok-Ring, assembled behind the welded-on ring, provide the means of restraint. The split Lok-Ring is held "snug" against the pipe O.D. for assembly of the Fastite Joint. After the plain end of the pipe is assembled into the Lok-Ring bell, the Lok-Ring is released to permit it to expand. The Lok-Ring is thus securely positioned behind the welded-on ring and in the socket-locking groove on the I.D. of the Lok-Ring bell. This locks the joint. The Lok-Ring Restrained Joint is available for both pipes and fittings. For Lok-Ring fitting dimensions, weights, and configurations, please refer to Fastite Pipe and Fittings.

This joint can be easily disassembled if the need develops, using the closure-spreader mechanism provided for this purpose.

ACIPCO Lok-Ring Joint pipe can be furnished with standard or special coatings and/or linings.

Notes:

* U.S. Patent 4,428,604.
** Contact ACIPCO if higher pressure rating is required.

ACIPCO Lok-Ring Joint Assembly Instructions

Thoroughly clean the socket-locking groove as well as the Fastite gasket recess and pipe plain end, being sure to remove any mud, gravel, or other foreign matter. Insert the standard Fastite gasket and lubricate the joint components in accordance with standard Fastite assembly instructions; and, with pipe in essentially straight alignment, assemble the plain end into the Lok-Ring bell. (Photos 1 & 2: assembly tools shown in photo 2 are available from ACIPCO for installers not electing assembly with a backhoe or other similar equipment.) Once the spigot is completely inserted, as evidenced by the spigot stripe disappearing into the bell (the orientation of the spigot stripe in relationship to the bell face is an indication of pipe alignment), loosen the outside stud closure nuts fully to the end of the stud to allow the Lok-Ring to spring outward and into the socket-locking groove. (Note: For export, the Lok-Ring is normally shipped in export boxes or crates to prevent damage during transportation.) In lieu of the outside stud closure nut provided for this purpose, some installers prefer to install a "quick release" locking clamp or grip device beforehand (for example: "outside the trench") and back the outside closure nut out of the way for very rapid assembly (Photo 3). The correct seating of the Lok-Ring in the socket-locking groove should be accompanied by an obvious spreading of the Lok-Ring struts. If inspection around the joint reveals that the Lok-Ring is not completely seated in the annular socket-locking groove at any location, the Lok-Ring may be completely seated by moving the entering pipe slightly and/or by tapping the loose Lok-Ring into the socket-locking groove with a flat caulking tool. (Note: It is imperative that the installer verify that the Lok-Ring is seated outward in the groove all around the joint. Lok-Rings are painted yellow to aid in this verification.) When a visual inspection to determine the Lok-Ring position is not practical, such as in an underwater installation, a feeler gauge can be used to ensure that the Lok-Ring is correctly seated in the socket-locking groove all around the joint (Photo 4). Once the Lok-Ring is correctly seated in the socket-locking groove, turn the inside stud spreader nuts out firmly against the struts as shown (Photo 5) to ensure firm contact of the Lok-Ring in the socket-locking groove. During the Lok-Ring spreading operation, the outside stud closure nuts should be positioned so as not to restrict the outward movement of the drilled struts on the stud. (The outside stud closure nuts perform no function in the finished joint; however, these closure nuts can be used to effect simple disassembly of the joint, if required, by reversing the assembly procedure outlined above.) Once the inside spreader nuts are properly positioned, the Lok-Ring is positively secured in the socket-locking groove.

Photo 1 Photo 2 Photo 3 Photo 4 Photo 5

Field Assembly of Lok-Ring

When placing the Lok-Ring on the pipe in the field, unscrew and remove one outside stud closure nut to permit the Lok-Ring to be spread and positioned on the plain end of the pipe behind the welded-on ring.

To complete field placing of the Lok-Ring on the pipe, reassemble the outside stud closure nut and tighten both outside stud closure nuts to pull Lok-Ring substantially flush against the pipe barrel and immediately behind the welded-on ring.

Note: The ACIPCO Lok-Ring Joint allows for joint take-up after installation. In most underground installations, including most restrained bend locations, this feature is advantageous in that increased thrust-resisting soil forces are generated. Also, expansion and contraction due to temperature variations may be accommodated without excessive stress in the pipe members.

In any application where axial or lateral movement may be undesirable, such as certain bridge crossings, certain other exposed piping applications, or certain connections of restrained pipe sections to rigid piping, special design or installation provisions may be necessary to control any unacceptable pipeline movement. Depending on job conditions and restrained pipe length, cumulative joint take-up can be substantial, particularly in exposed piping applications. In this regard, joints may be extended after assembly to minimize further joint take-up in test or service.

The amount of joint take-up or line movement in buried restrained pipelines is substantially limited by the surrounding soil. Therefore, system security and safety is maximized by filling and testing restrained sections of pipelines after backfilling as recommended by ANSI/AWWA C600, Installation of Ductile Iron Water Mains and Their Appurtenances.

Metric Lok-Ring Dimensions