Sidewall fusion method for fusing branch outlets to host plastic pipe and apparatus for use therein

A method of forming a connection between a proximal end of a fitting and a cylindrical sidewall region of a second, host pipe, the fitting and second, host pipe being formed from a material selected from the group consisting of polyethylene, polyvinyl chloride or polypropylene, the method comprising the steps of:

• heating the proximal end of the fitting and a selected cylindrical sidewall region of the second, host pipe with a heating apparatus in a first step, the proximal end of the fitting defining a fusion interface for the fitting and the second, host pipe defined by an arc length of contact of a base diameter of the fitting on the selected cylindrical sidewall region of the second, host pipe, the heating apparatus being applied under pressure to the proximal end of the fitting and the selected cylindrical sidewall region of the second, host pipe until the respective second, host pipe and fitting have reached a softening temperature of the selected material;
• after the heating step, removing the heating apparatus from the fitting and second, host pipe;
• after the heating and removing steps, directly contacting the proximal end of the fitting to the second, host pipe;
• again applying pressure to the fitting after the contacting step so that the proximal end of the fitting is pushed against the second, host pipe, applying even pressure about the circumference of the proximal end of the fitting on the second, host pipe;
• wherein the heating step is performed with a heating apparatus which comprises a deformable thin flexible heating blanket having opposed first and second sides sized and configured to mate with the proximal end of the fitting and the cylindrical sidewall region of the second, host pipe and extend beyond the arc length of contact of a base diameter of the fitting on the selected cylindrical sidewall region of the second, host pipe;
• and
• wherein the pressure applied during the heating step to the second, host pipe and fitting is sufficient to bend and squeeze the deformable thin flexible heating blanket to get an initial melt-film between the second pipe, deformable thin flexible heating blanket and fitting, which eventually spreads into dimensional compliance.

A method of forming a connection between a proximal end of a fitting and a selected region of a second, host pipe, the fitting and second, host pipe being formed from a synthetic polymeric material, the method comprising the steps of:

• heating the proximal end of the fitting and the selected re ion of the second, host pipe with a heating apparatus in a first step, the heating apparatus being applied to the proximal end of the fitting and the selected region of the second, host pipe until the fitting and the second, host pipe have reached a softening temperature;
• after the heating step, removing the heating apparatus from the fitting and second, host pipe;
• after the heating and removing steps, directly contacting the proximal end of the fitting to the second, host pipe;
• exerting pressure so that the proximal end of the fitting is pushed against the second, host pipe to thereby fuse the fitting and second, host pipe;
• wherein the heating step comprises a step in a fusion-weld method and is performed with a heating apparatus which comprises a flexible heating blanket having opposed first and second sides sized and configured to mate with the proximal end of the fitting and the selected region of the second, host pipe for heating the respective fitting and second, host pipe to a fusion temperature;
• wherein the flexible heating blanket fusion-weld method described is used for forming custom diameter pipe mains, requiring custom radius branch saddle base, and the use of a custom radius heater;
• wherein, when the fusion-weld method is used as a part of a method of installing custom diameter pipe mains using compression-fit technology, where branch outlet tees are required in the field, and where the second, host pipe has a wall section which is removed at a selected location, and a reducing tee branch outlet must be fusion-welded to a custom outer diameter of the second, host pipe, the method further comprising the steps of:
• measuring or estimating a contour of the custom outer diameter of the second, host pipe;
• saw cutting or machining a branch outlet saddle to the previously measured or estimated contour of the custom outer diameter of the second, host pipe;
• installing a flexible, perforated heater blanket which has been sized to conform to the previously measured or estimated contour of the outer diameter of the second, host pipe, thereby enabling the components to be co-melted and fusion-welded under controlled interfacial fusion pressures to create a fusion-weld joint.

A method of forming a connection between a proximal end of a fitting and a selected region of a second pipe, the fitting and second pipe being formed from a synthetic polymeric material, the method comprising the steps of:

• heating the proximal end of the fitting and the selected region of the second pipe with a heating apparatus in a first step, the heating apparatus being applied to the proximal end of the fitting and the selected region of the second pipe until the fitting and the second pipe have reached a softening temperature;
• after the heating step, removing the heating apparatus from the fitting and second pipe;
• after the heating and removing steps, directly contacting the proximal end of the fitting to the second pipe;
• exerting pressure so that the proximal end of the fitting is pushed against the second pipe to thereby fuse the fitting and second pipe;
• wherein the heating step is performed with a heating apparatus which comprises a flexible heating blanket having opposed first and second sides sized and configured to mate with the proximal end of the fitting and the selected region of the second pipe for heating the respective fitting and second pipe to a fusion temperature;
• wherein the flexible heating blanket is a custom dimensioned, flat, perforated blanket, with a surface waft intensity of 4 to 8 watts per square inch.

A method of forming a connection between a proximal end of a fitting and a selected region of a second pipe, the fitting and second pipe being formed from a synthetic polymeric material, the method comprising the steps of:

• heating the proximal end of the fitting and the selected region of the second pipe with a heating apparatus in a first step, the heating apparatus being applied under pressure to the proximal end of the fitting and the selected region of the second pipe until the fitting and the second pipe have reached a softening temperature;
• after the heating step, removing the heating apparatus from the fitting and second pipe;
• after the heating and removing steps, directly contacting the proximal end of the fitting to the second pipe;
• again exerting pressure so that the proximal end of the fitting is pushed against the second pipe to thereby fuse the fitting and second pipe;
• wherein the heating step is performed with a heating apparatus which comprises a deformable thin flexible heating blanket having opposed first and second sides sized and configured to mate with the proximal end of the fitting and the selected region of the second pipe for heating the respective fitting and second pipe to a fusion temperature,
• wherein the pressure applied during the heating step is a simple manual pressure applied to the second pipe and fitting which is sufficient to bend and squeeze the deformable thin flexible heating blanket to get an initial melt-film between the second pipe, deformable thin flexible heating blanket and fitting, which eventually spreads into dimensional compliance.