Introducing The Permalok Type 7 Pressure
Connection – Enabling One-Pass Trenchless Installations, Even for Pressure Applications!

St. Louis, MO – Permalok Corporation, exclusive source of the patented Permalok interlocking pipe joining system serving the trenchless construction industry, has introduced a new solution to dramatically reduce the time and cost required to install carrier pipe via trenchless construction methods. The new Permalok Type 7 connection has been tested and proven to be leakproof up to 300 psi, and is currently available in pipe sizes up to 150” O.D.

The Problem – High Costs and a Slow Process
Prior to Permalok’s Type 7 connection, trenchless installations of waterlines, sewer force mains and other fluid conveyors under highways and railroads – as well as long microtunneled water and sewer lines – usually required the use of a steel casing with a carrier pipe placed inside after completion of the tunnel. This “two pass” technique is costly and time consuming, since owners are paying twice for the labor, equipment and pipe.

The use of traditional steel pipe as the carrier in a “one pass” trenchless installation required field welding the pipe joints. Due to the pressures involved, this required significant time, specialized labor, and weld inspections to assure quality. To compound problems, the field welding usually caused damage to the coatings and linings at the site of the weld; repairs to the coatings and linings required more time and money to restore.

The Solution – Apply a Better Process to Carrier Pipe
Permalok solved the problem of field welding steel casing pipe years ago with our patented interlocking pipe joining system for microtunneling, pipe jacking, ramming and auger boring. But the Permalok casing pipe, while watertight to groundwater pressures, still required a pressure rated carrier pipe to be threaded inside to complete the line.