What Does Tunnel Lubrication Systems Mean?
A tunnel lubrication system is defined as a method of delivering a constant film of lubricant along the circumference of the entire pipe string. Tunnel lubrication systems are used during tunneling and pipe jacking, directional drilling, auger boring and well drilling to reduce friction. A mixture of bentonite and polymers is used.
Trenchlesspedia Explains Tunnel Lubrication Systems
The purpose of a lubrication system is to fill the void created around the circumference of the pipe or drill string called the annulus. This is accomplished by including lubrication stations in the drill string to inject the lubricant directly into the annulus. The lubricant, also referred to as mud, is of a bentonite and polymer mixture, but the exact composition depends on the ground in which it will be used.
A tunnel lubricant system consists of a control unit, a mixing and storage tank, main jacking stations, a lubrication station, a lubrication ring, a number of pumps, feed line and injection fittings.