A tubing system with a coupler join positioned between and joining tubing segments. The coupler join is formed to reduce dead legs and hold up volumes within, and/or to reduce materials used to form, and/or to simplify the manufacturing process of the tubing system. The coupler join may be sized, shaped, configured, and/or dimensioned to join tubing segments, such as pre-formed tubing segments, in a streamlined configuration, such as to substantially correspond with the outer and inner diameters of the tubing segments. The tubing system and coupler join may be formed with a mold configured to form a coupler join securely coupling spaced apart ends of tubing segments to be joined together in a configuration which reduces dead legs and hold up volumes within the resulting tubing system.

A heat-weldable weld fitting that has a cylindrical fitting main body portion. The cylindrical fitting main body portion includes an outer periphery including a first end portion, a second end portion, and a middle section between the first end portion and the second end portion, and positioning scales formed at equal intervals in a peripheral direction of the second end portion of the outer periphery of the fitting main body portion. The first end portion being configured to be heated by a heater and is welded to an end portion of another weld fitting. The positioning scales are configured to define an angular portion of the weld fitting relative to the welding apparatus at the time of welding the first end portion to the first end portion of another weld fitting by matching the positioning scale with a reference mark provided on the clamp portion of the welding apparatus.

A tubing including an overmold is connected to a fitting by welding the overmold to the fitting. Methods for doing the same are also provided. Also provided are methods for forming an overmold on a tubing or on a tubing and fitting assembly.

A tubing including an overmold is connected to a fitting by welding the overmold to the fitting. Methods for doing the same are also provided. Also provided are methods for forming an overmold on a tubing or on a tubing and fitting assembly.

A tubing including an overmold is connected to a fitting by welding the overmold to the fitting. Methods for doing the same are also provided. Also provided are methods for forming an overmold on a tubing or on a tubing and fitting assembly.

Methods and apparatus are described for producing welded assemblies of plastic parts for use in fluid flow applications. A unit cell structure is disclosed for use in an assembly. One embodiment is an as-molded plastic unit cell structure for use in fabricating welded fluid flow assemblies, the cell structure comprising a hollow tubular body portion having opposed first and second axial ports, a first hollow tubular portion extending axially from a first end of the tubular body portion and defining the first axial port, the first hollow tubular portion having a tube or pipe end configured for welding to another plastic part in a fabrication process for an assembly, and wherein the first tubular portion has a length in a range of 1 mm to 40 mm.

Methods and apparatus are described for producing welded assemblies of plastic parts for use in fluid flow applications. A unit cell structure is disclosed for use in an assembly. In an exemplary embodiment, an assembly of welded plastic parts for a fluid flow application includes a plurality of as-molded plastic unit cell structures, each cell structure having a hollow tubular body portion, a first tubular portion extending axially from a first end of the tubular body portion, and second and third opposed transverse tubular portions extending from an intermediate portion of the tubular body portion transverse to the first tubular portion. The first tubular portion of a first unit cell structure is welded to the first tubular body portion of a second unit cell structure in an axially aligned configuration.