THE BASIC LINER INSTALLATION MECHANISM

The FLUTe liner is usually made of a urethane coated Nylon fabric in tubular form. The liner is often installed in a hole with the interior of the liner filled with water (see the figure below). The water pressure presses the liner firmly against the hole wall. A cord, called a tether, is attached to the bottom end of the liner. If that cord is pulled upward, the liner is peeled inside-out out of the hole. The liner is said to "invert" as it is pulled upward. The water level in the liner rises as the liner is shortened by the inversion. At the surface, the tether, followed by the liner, can be wound on a reel. The third drawing shows the liner nearly fully removed from the hole with the water spilling over the top of the pipe to which the top end of the liner is attached.

The installation of the liner is the precise reversal of the procedure. The liner is filled with water which forces it to roll out against the hole wall as it descends into the hole. This process, the reverse of inversion, is called "eversion." By adding water and allowing the liner to pull itself to the bottom of the hole, one is back to the initial state with the liner fully extended in the hole.

The same installation and removal procedure is possible using air as the driving fluid instead of water. In that case, the liner can be everted into a hole horizontally. . This is done by enclosing the reel in a pressure canister (see vadose application for pressure canister installation). The open top end of the liner is attached to a pipe extending from the canister.

The attributes of the inverting/everting liner are very useful: The liner supports and seals the hole wall. The liner carries instruments (e.g., absorbers and sampling tubing) into position and isolates them one from another. The method is gentle, fast, and low cost. The liner travels equally well through: vertical, horizontal, enlarged, constricted and curved holes. Using water to drive the liner allows installation in water filled and mud filled holes. Liners can be held in place for years, without hole collapse, with a sand fill. A major advantage of the flexible liner is how well it conforms to the shape of the passage into which it is installed. This provides an extraordinary sealing capability in geologic formations and piping. The 18 years of flexible liner experience available at FLUTe have allowed the refinement of the many aspects of the technology from the fabrication methods to the installation procedures and choice of materials. The mechanism is simple, but not intuitively obvious. Above the earth, flexible liners have been used for a variety of robotic type applications, including remote sampling.

The uses are many: Liners of many strengths, materials, and sizes are available for a wide variety of applications. Our most popular systems are described under applications and methods. The named systems are described under systems.

The rest of this web site describes the various applications, installation procedures, sampling procedures, and many related presentations and papers on the use of flexible liners. The range of applications can be seen most easily at Applications.

Not all FLUTe liners are everting/inverting liners, but most methods use the mechanism for either installation and/or removal. FLUTe also has a wide range of calculational models for use in the installation, function in place, and many other mechanical engineering aspects of flexible liners. There is a good chance that we have already addressed the feasibility of your special application. We welcome dialogue concerning new environmental challanges you may be facing at your site. FLUTe products and uses have continually expanded as we have sought solutions for specific sites. Please contact us at for any special information.