초록 ▼

A large tubular plastic tank, for use in holding unpressurized water or wastewater, is formed by fusion welding together half-shell parts at lengthwise flange joints to form a tubular body. Then, end caps are fusion welded onto the outermost ends of the tubular body and an assembly of two or more bo

A large tubular plastic tank, for use in holding unpressurized water or wastewater, is formed by fusion welding together half-shell parts at lengthwise flange joints to form a tubular body. Then, end caps are fusion welded onto the outermost ends of the tubular body and an assembly of two or more bodies. Fusion weld elements are secured beforehand to the joining surfaces of the tank parts at a factory; the tank parts are then economically stored or shipped in nested condition to a fabrication site remote from the manufacturing site. Electric or electromagnetic energy is used to melt in situ the fusion weld elements which are captured between the joining surfaces of the parts.

대표청구항 ▼

1. A method of making a tubular plastic tank or a portion thereof, the tank having a length axis, comprising: (a) molding at a first location a plurality of half-shells, each having two lengthwise flanges with lengthwise joining surfaces thereon, and each having opposing end semi-circumferential fla

1. A method of making a tubular plastic tank or a portion thereof, the tank having a length axis, comprising: (a) molding at a first location a plurality of half-shells, each having two lengthwise flanges with lengthwise joining surfaces thereon, and each having opposing end semi-circumferential flanges with semi-circumferential joining surface thereon;(b) securing one or more first fusion weld elements to at least one of said lengthwise joining surfaces of each half-shell;(c) molding a plurality of end caps, each end cap having a circumferential joining surface, half of which circumferential joining surface is shaped to mate with one of said half-shell semi-circumferential joining surfaces;(d) positioning one or more second fusion weld elements on one or more half-shell semi-circumferential joining surfaces or on the circumferential joining surface of at least one end cap;(e) nesting the half-shells within each other and nesting the end caps within each other; then transporting the nested half-shells and the nested end caps to a second location that is remote from the first location; then,(f) mating the lengthwise joining surfaces of two half-shells to each other to form an assembly having two lengthwise joint regions, each joint region capturing at least one first fusion weld element;(g) melting said one or more first fusion weld elements by applying electrical or electromagnetic energy thereto, thereby to form a first tubular body having two opposing side lengthwise weld joints and opposing first and second ends, each end comprising a circumferential flange with a joining surface thereon;(h) mating at least a first end cap to the first end circumferential flange of the first tubular body, to form an assembly having a circumferential joint region capturing at least one said second fusion weld elements; and,(i) melting said at least one second fusion weld element by applying electrical or electromagnetic energy thereto; to thereby join the first end cap to the first tubular body. 2. The method of claim 1 which further comprises: mating two additional half-shells to each other to form a second tubular body like the first tubular body and joining the second tubular body to the first tubular body by securing one or more third fusion weld elements to the second circumferential flange end of at least one of the tubular bodies;mating the first tubular body and the second tubular body so said one or more third fusion weld elements are captured in a circumferential joint region therebetween;melting said one or more third fusion weld elements by applying electrical or electromagnetic energy thereto; to thereby join the second tubular body to the first tubular body. 3. The method of claim 1 which further comprises: after step (i), attaching a second end cap to the second circumferential flange end of the first tubular body. 4. The method of claim 1 wherein, during step (b) said at least one or more first fusion weld elements is secured to one only of the lengthwise joining surfaces of each half-shell. 5. The method of claim 1 wherein at least one of the first fusion weld elements is secured to each joining surface by either tack welding or placement in a groove. 6. The method of claim 1 wherein said at least one or more first fusion welding elements which is secured to the lengthwise joining surfaces during step (b) is of the loop type and has a pair of terminal ends which exit from the end of a lengthwise joint region in step (f). 7. A method of making a tubular plastic tank or a portion thereof, the tank having a length axis, comprising: (a) molding a plurality of half-shells, each having two lengthwise flanges, each flange having a lengthwise joining surface thereon; each half shelf comprising opposing end semi-circumferential flanges, each flange having a semi-circumferential joining surface thereon; wherein each lengthwise flange has a tab extending from one or both ends thereof, each tab comprising a tab surface which is parallel to the lengthwise joining surface of the flange;(b) securing one or more first fusion weld elements to at least one of said lengthwise joining surfaces of each half-shell, at least one first fusion weld element configured for running across one of said tab surfaces;(c) nesting the part-shells within each other and nesting the end caps within each other; then transporting the nested part-shells and the nested end caps to a second location that is remote from the first location; then,(d) mating the lengthwise joining surfaces of two half-shells to each other to form an assembly having two lengthwise joint regions and at least one pair of mated tabs, each joint region and each pair of mated tabs capturing said one or more first fusion weld elements;(e) melting said first fusion weld elements by applying electrical or electromagnetic energy thereto, thereby to form a first tubular body having two opposing side lengthwise weld joints and opposing ends having first and second ends, each end comprising a circumferential flange with a joining surface thereon;(f) mating at least a first end cap to a first circumferential flange end of the first tubular body, to form an assembly having a circumferential joint region capturing an at least one second fusion weld element; and,(g) melting said at least one second fusion weld element by applying electrical or electromagnetic energy thereto; to thereby join the first end cap to the first tubular body; and(h) severing the tabs from the half-shells which then comprise said first tubular body. 8. A method of fabricating a plastic tank or a portion thereof, the tank having a length axis, which comprises: (a) molding at a first location a plurality of part-shells, each having two lengthwise flanges with lengthwise joining surfaces thereon, and each having opposing end part-circumferential flanges with part-circumferential joining surface thereon;(b) securing one or more first fusion weld elements to at least one of said lengthwise joining surfaces of each part-shell;(c) molding a plurality of end caps, each end cap having a circumferential joining surface, part of which joining surface is shaped to mate with part of one of said part-shell part-circumferential joining surfaces;(d) securing one or more second fusion weld elements to said one or more part-circumferential joining surfaces of the part-shells or to the circumferential joining surface of at least one end cap;(e) nesting the part-shells within each other and nesting the end caps within each other; then transporting the nested part-shells and the nested end caps to a second location that is remote from the first location; then,(f) mating the lengthwise joining surfaces of a multiplicity of said part-shells to form a tubular shape assembly having two or more lengthwise joint regions, each joint region capturing said one or more first fusion weld elements;(g) melting said first fusion weld elements by applying electrical or electromagnetic energy thereto, thereby to form a first tubular body having two or more lengthwise weld joints and opposing ends having circumferential flanges with joining surfaces thereon;(h) mating at least a first end cap to a circumferential flange end of the first tubular body, to form an assembly having a circumferential joint region capturing at least one said second fusion weld element; and,(i) melting said at least one second fusion weld element by applying electrical or electromagnetic energy thereto; to thereby join the first end cap to the first tubular body. 9. The method of claim 8 which further comprises: after step (g), attaching a second end cap to a circumferential flange end of the first tubular body using the same method as was used to attach the first end cap. 10. The method of claim 8 wherein each of said one or more first fusion weld elements has a terminal end for connection to a source of electric energy, further comprising: forming each said part-shell with one or more tabs, each tab extending from an end of the part-shell lengthwise flange with a tab surface parallel to the lengthwise joining surface of the flange;wherein when the part-shells are mated as the tubular shape assembly in step (f) the terminal end of each fusion weld element that is captured in the joint region is captured between mating surfaces of two said tabs; and,after carrying out said melting and welding step (f), severing the tabs from the part-shells which then comprise said first tubular body. 11. The method claim 7 further comprising: (f) molding at least one cap having a circumferential joining surface, mating said surface with a circumferential flange joining surface of the first tubular body and welding the end cap joining surface to the first tubular body circumferential end joining surface. 12. The method of claim 1 wherein in step (d) two second fusion weld elements are provided, each second fusion weld element in the form of a loop having a loop end and free ends, and each second fusion weld element running around the semi-circumferential joining surface of a half shell with a length such that, when two half shells are mated in step (f), the free ends of one second fusion weld element circumferentially overlap the loop end of the other second fusion weld element on the circumferential flange joining surface at an end of the first tubular body which is formed in step (g). 13. The method of claim 12 wherein, after step (g), the free ends of a second weld element loop that is secured to the flange of one half-shell are run through holes in the joining surface of the semi-circumferential flange of the mating half-shell. 14. The method of claim 7 wherein in step (c) a two second fusion weld elements are provided, each in the form of a loop having a loop end and free ends, and each second fusion weld element runs around the semi-circumferential joining surface of a half shell with a length such that, when two half shells are mated and welded in steps (e) and (g), the free ends of one second fusion weld element circumferentially overlap the loop end of the other second fusion weld element on the circumferential flange joining surface at an end of the first tubular body.