Sealable drain pipe coupling

A drain pipe coupling to sealably couple an insert pipe with an existing drain pipe, said drain pipe coupling comprising:

• a. a tubular body concentrically positioned in said insert pipe and said existing drain pipe;
• b. a coil spring with an adjustable diameter, positioned around a proximal end of the tubular body, with two actuation ends extending inward, wherein movement of the two actuation ends toward and apart from each other decreases and increases diameter of the coil spring, respectively;
• c. an elastic tubular cover concentrically positioned over both the coil spring and the proximal end of the tubular body and having an internal diameter appropriately sized and contoured to grip the proximal end of the tubular body and forms a seal at interface between the elastic tubular cover and the tubular body, and
• d. an actuation element positioned within an interior of the tubular body adjacent to the proximal end, configured to slide axially within the tubular body and engage the actuation ends of the coil spring, wherein the actuation element is connected to a handle extending through a length of the tubular body, wherein the handle is accessible from a distal end of the tubular body and an axial movement of the handle causes the axial movement of the actuation element within the tubular body and causes a change in the spacing between the actuation ends of the coil spring, thereby adjusting the diameter of the coil spring and whereby an increase in the diameter of the coil spring expands and deforms the elastic tubular cover, allowing the proximal end of the drain pipe coupling to grip and seal the insert pipe and the existing drain pipe.