Method for installing a pipe liner

A method for installing a pipe liner in a pipe comprising the steps of:

• reducing the diameter of the liner so that it can be positioned within the pipe;
• installing the liner in the pipe;
• enlarging an upstream end of the liner;
• disposing a liner expander having at least one disk shaped expanding portion within the upstream end;
• inserting a plug in the upstream end of the liner;
• connecting a source of heated fluid, the fluid heated external to the liner, to the plug, the heated fluid having a temperature sufficient to soften the liner for mechanical expansion by the liner expander;
• injecting the heated fluid through the plug and into the liner, upstream of the liner expander, and allowing a portion of the heated fluid to pass through the liner expander for heating and softening the liner immediately ahead and in front of the liner expander;
• pressurizing the upstream end of the liner with the heated fluid at a pressure being sufficient to propel the liner expander from the upstream end to a downstream end of the liner for continuously, progressively engaging the liner with the expanding portion of the liner expander to mechanically expand the liner into contact with the pipe;
• attaching an exhaust means to the downstream end of the liner;
• and
• cooling the externally supplied source of heated fluid while monitoring the pressure and temperature of the fluid in the exhaust for maintaining the pressure within the liner at a temperature sufficient to maintain the liner in its expanded condition, until the temperature has dropped below the softening temperature of the liner.