Patent ID: 6156139
Filing Date: 2000-12-05
Classification: B29C

Abstract:
A process for fusing a polyolefin stack pipe to the sidewall of a polyolefin main pipe using a computer and a fusing apparatus with a travel head and a base inside which a heating plate with a concave upper surface and a convex lower surface is disposed, the process comprising the steps of:(1) providing power to said computer;(2) connecting said computer to said fusing apparatus;(3) providing said computer with software capable of processing parameters for fusing polyolefin pipe with input data related to characteristics of said stack pipe and said main pipe;(4) connecting pneumatic air lines to said fusing apparatus;(5) installing said stack pipe in said fusing apparatus;(6) positioning said stack pipe perpendicular to a section of said main pipe;(7) clamping said base onto said main pipe;(8) performing steps of a set-up sequence, including determining(a) distance from an upper surface of said heating plate in its lowered position to an uppermost portion of said heating plate in a fully raised position;(b) thickness of said heating plate;(c) length of said stack pipe;(d) distance the stack pipe will migrate into the main pipe; and(e) setting said travel head in a position which accounts for the measurements in (a) through (d) in order to maintain proper pressure and clearances during each cycle of the process;(9) heating said heating plate;(10) lowering the heating plate onto said main pipe;(11) pneumatically applying pressure onto said upper surface of said heating plate in order to seat said heating plate;(12) raising said stack pipe;(13) pneumatically applying pressure onto said upper surface of said heating plate for a time period sufficient to cause a heated portion of said main pipe to conform to said convex lower surface of said heating plate;(14) exhausting pressure from said fusing apparatus;(15) continuing to heat said heating plate;(16) raising said heating plate from between said lower end of said stack pipe and said heated portion of said main pipe;(17) pneumatically lowering said lower end of said stack pipe onto said heated portion of said main pipe, under pressure, resulting in a fusion of said pipes;(18) allowing said fusion to cool;(19) testing said fusion for its ability to withstand pressure.