Total containment welding of plastic tubes

• US 5,674,333 A
• Filed: 03/06/1995
• Issued: 10/07/1997
• Est. Priority Date: 10/23/1992
• Status: Expired due to Term

• Current Assignee: Genesis BPS, LLC
• Original Assignee: DENSO Corporation
• Inventors: Spencer, Dudley W. C.
• Primary Examiner(s): Simmons, David A.
• Assistant Examiner(s): Rivard, Paul M.
• Application Number:
  US08/399,339
• Time in Patent Office: 946 Days
• Field of Search: 156/64, 156/158, 156/159, 156/304.2, 156/304.6, 73/46, 73/49.1, 73/49.3, 73/52
• US Class Current: 156/64
• CPC Class Codes: A61M 39/146 by cutting and welding
• CPC Class Codes: B29C 57/10 Closing
• CPC Class Codes: B29C 65/2046 using a welding mirror which also cuts the parts to be joined, e.g. for sterile welding
• CPC Class Codes: B29C 65/7802 Positioning the parts to be joined, e.g. aligning, indexing or centring
• CPC Class Codes: B29C 65/7841 Holding or clamping means for handling purposes clamping means for the purpose of applying pressure on the parts to be joined, in the area to be joined B29C66/81; work holders in general B25B; devices for holding or positioning work for welding metal B23K37/04
• CPC Class Codes: B29C 65/8215 Tensile tests
• CPC Class Codes: B29C 65/823 Bend tests
• CPC Class Codes: B29C 65/8246 Pressure tests, e.g. hydrostatic pressure tests
• CPC Class Codes: B29C 66/0018 being sterile
• CPC Class Codes: B29C 66/002 Removing toxic gases
• CPC Class Codes: B29C 66/1142 Single butt to butt joints
• CPC Class Codes: B29C 66/5221 for forming coaxial connections, i.e. the tubular articles to be joined forming a zero angle relative to each other
• CPC Class Codes: B29C 66/7373 Joining soiled or oxidised materials
• CPC Class Codes: B29C 66/73921 characterised by the materials of both parts being thermoplastics
• CPC Class Codes: B29C 66/80 General aspects of machine operations or constructions and parts thereof
• CPC Class Codes: B29C 66/857 Medical tube welding machines
• CPC Class Codes: B29L 2023/005 Hoses, i.e. flexible
• CPC Class Codes: B29L 2023/006 Flexible liners
• CPC Class Codes: B29L 2023/22 Tubes or pipes, i.e. rigid bent tubes not for use as pipe couplings B29L2023/004
• CPC Class Codes: B29L 2031/753 Medical equipment; Accessories therefor bloodbags, medical bags B29L2031/7148; artificial eyes B29L2011/0008
• CPC Class Codes: H01T 23/00 : Apparatus for generating ions to be introduced into non-enclosed gases, e.g. into the atmosphere

Abstract

Plastic tube sections are connected together by providing a pair of tubes each of which is inserted into the holder of a welding device in a bent condition so that each tube has a primary tube section and a secondary tube section with the primary tube sections being aligned with each other and the secondary tube sections aligned with each other. The tubes are heated by a wafer to create four separate tube sections which are then joined together in a dual weld wherein one of the welds joins the primary tube sections together and the other of the welds joins the secondary tube sections together. The welded primary tube sections are then separated from the secondary tube sections. Communication between each pair of tube sections is achieved by pressing the tube section open at the weld.

Claims

1. A method of testing the weld characteristics of a pair of primary tubes welded together comprising welding two primary tube sections together and two secondary tube sections together in a double weld made from heat softened tube sections pressed together under the same conditions including at the same time, temperature, compression and spacing conditions;

each of the secondary tube sections having a welded sealed closed end;

separating the double weld into a weld of the two primary tube sections and a weld of the two secondary tube sections;

opening communication between the two primary tube sections and between the two secondary tube sections; and

performing tests on the characteristics of the weld for the combined secondary tube sections having sealed remote ends to thereby indicate the comparable characteristics of the weld in the primary tube sections.

2. The method of claim 1 wherein each tube is inserted in a channel of a tube holder in a condition bent with the bent end exposed from the channel to form two sets of aligned tube sections;

and forming the primary tube from one set of aligned tube sections and the secondary tube from the other set of aligned tube sections.

3. The method of claim 2 wherein the welds are formed by a melt/wipe technique.

4. A method of creating a primary tube and a secondary tube comprising the steps of placing a first plastic tube in a bent condition in one holder of a welding device and placing a second plastic tube in a bent condition in a second holder of the welding device generally juxtaposed the tube in the first holder, each of the plastic tubes having a sealed closed end, the placing of the bent tubes causing the sealed closed ends of the plastic tubes to generally aligned with each other, severing the tubes at the area of each bend to create two sets of aligned tube sections which are heated to become soft, pressing each set of aligned heat softened tube sections together, simultaneously creating a dual weld from the two sets of aligned heat softened tube sections to create a primary tube from one set and a secondary tube from the other set, separating the dual weld to separate the welded primary tube from the welded secondary tube, the resultant secondary tube having one of the welded sealed closed ends at each end of the secondary tube with the weld separating the interior of the secondary tube into two separate closed chambers, the resultant primary tube having two separate chambers separated by the weld at the primary tube, and opening communication of the two separate chambers of the primary tube at the weld of the primary tube by popping open the weld of the primary tube.

5. The method of claim 4 wherein the first plastic tube and the second plastic tube are initially integral and are bent to form the two sets of tube sections, joining the secondary tube sections together by the weld to form a closed loop.

6. The method of claim 4 wherein the first tube and the second tube are initially separate from each other, and the secondary tube sections are welded together to form a single sample tube.

7. The method of claim 4 wherein one of the primary tube sections is connected to a bag and the other of the primary tube sections extends the overall length of the combined primary tube sections.

8. The method of claim 7 wherein the extended primary tube section includes additional components which are permitted to flow into the combined primary tube sections.

9. A method of creating a primary tube and a secondary tube comprising the steps creating placing a first plastic tube in a bent condition in one holder of a welding device and placing a second plastic tube in a bent condition in a second holder of the welding device generally juxtaposed the tube in the first holder severing the tubes at the area of each bend to create two sets of aligned tube sections, pressing each set of aligned tube sections together, simultaneously creating a dual weld from the two sets of aligned tube sections to create a primary tube from one set and a secondary tube from the other set, separating the dual weld to separate the welded primary tube from the welded secondary tube, opening communication of the primary tube at the weld of the primary tube, and a second welding device is used to connect a further primary tube section with one of the primary tube sections whereby three primary tube sections are connected together which include a central primary tube section.

10. The method of claim 9 wherein the central primary tube section includes an added component.

11. The method of claim 10 wherein the central section includes a tube having two chambers separated from each other with each chamber having a different component, and opening communication between the chambers immediately prior to joining the central primary tube section to the other primary tube sections.