Muddy water is not a dream product for a utility — or for a company putting waterlines in place. When King Drilling of London, Ontario, was frustrated by mud and slurry getting into water mains during placement, the company did something about it.

“In our work, one of the biggest problems we encounter is keeping drill mud out of a water main,” says Chris King, owner and president of the company. “When the slurry we use to get a pipe through the ground gets into a potable water mainline, it means a lot of extra expense.”

To join sections of PVC pipe being inserted into a drilled tunnel, King utilizes the Cobra Lock joint restraint system. Cobra Lock is one of two types of locking pipe in Canada, the other being Caribou.

“They’re both good, but I’ve found Cobra Lock is the easiest to work with and put together,” King says. “That’s important because a lot of times when we’re installing pipe in an urban area, we don’t have the room to let sections of connected pipe trail out. We have to put the sections together one at a time as we’re drilling, and we can do that faster with Cobra Lock than with Caribou.”

The Cobra Lock system consists of a short length of pipe, a coupling and two locking splines. A firm connection is relatively quick to make and ensures that, when being pulled into place, the pressure on the joint is evenly distributed around the circumference of the pipe.

In any event, King wanted a pull-head for his HDD machine that would firmly grasp the end of a pipe and simultaneously seal the end against any intrusion of mud or slurry. He scouted around and found that no manufacturer offered such a tool.

“They don’t exist,” he says. “So I bought a fitting and took it to a tool-and-die maker and had him create a pulling head for me.”

It works. No more slurry-in-the-pipe problem.

Read more about King Drilling in the April 2021 issue of Dig Different magazine.