Denco Corporation

John B Shaposka

Dudley W Spencer

Robert J Beird

A process for sterile entry/exit into a closed system permits safe addition of reagent/nutrient/process modules, etc., removal of biological samples or depleted process modules such as filters, etc. all without exposing the operator to possibly dangerous materials such as blood and without endangering the contents of the system such as in cell-culturing. A novel welder and process is disclosed to illustrate the process.

Sterile entry/exit total containment process for closed systems using

A plastic tube is cut into two sections which are sealed closed by a sterile method wherein the tube is loaded into two clamping jaws which flatten the tube. The tube is cut through the flattened section and the cut ends are heated to their molten state. A wafer having wings is located between the cut ends with the wings penetrating the lumens to create an internal plug as the wings force the molten material inwardly. The plugs add to the strength of the resultant seal. If desired, the molten ends are pressed into a cavity which is cooled to a temperature below the molten temperature to seal the ends. The tubes are then removed from the cavity. When it is desired to connect individual tube sections the two tube sections are placed in clamp members in axial alignment slightly spaced from each other. The ends of the tube sections are melted by a melt/wipe process and the tube sections are then pressed into contact with each other to be welded into an integral tube. The same device is used for both the sterile disconnect and connect procedures.

Total containment welding of plastic tubes

Plastic tubes are welded by placing a pair of tubes in a pair of aligned holders with each tube folded toward itself. A wafer is movably mounted in the gap between the tubes and is heated to cause the ends of the tubes to melt without actually cutting through the tubes. The melted ends of opposed tubes can be pressed into contact with each other to form a welded connection. In a variation a pair of cutting blades cut the folded ends of the tubes and the cut ends are then melted by a wafer and subsequently pressed into contact with each other.

Total containment welding or plastic tubes

Plastic tubes are welded together by placing each tube in a nest which includes a pair of grooves and an anvil centrally located between the grooves. Each tube is positioned in the grooves around the anvil for being juxtaposed the other tube. A wafer of movably mounted to move to the gap between the anvils so as to heat the ends of the tubes and melt the tubes without actually cutting through the tubes. The melted ends are then joined together so that the two tubes are thereby connected with one section of each tube being in flow communication with a corresponding section of the other tube.

Two thermoplastic tubes are welded together by pre-cutting the tubes to create two ends which are axially aligned when placed in a holding device. A wafer is inserted in the space between the cut ends and the wafer is heated to melt the cut ends while the cut ends are in a non-flattened condition. After the wafer is removed the melted cut ends are pressed against each other to weld the cut ends together.

Techniques for welding thermoplastic tubes

Two thermoplastic tubes are welded together in a process which includes severing the tubes by a severing wafer having a temperature of about 350.degree. F. to create two cut sections. The severing wafer is removed from the space between the tubes and a hot wafer having a temperature of 500.degree.-1200.degree. F. is inserted in the space to radiantly heat the tube ends so that they are welded when pressed-together while in an unflattened and open condition.

A plastic tube is sealed at its end by placing the tube in a pair of spaced apart tube holders having tube receiving pockets. The tube is cut by a cutting device movable into and out of the space between the pockets to form two distinct tube sections which are melted at their ends while in the clamped condition. The cut ends are then brought into contact with each other in a mis-aligned condition offset by one-half the thickness of a tube wall to seal the tube end.

Sealing of plastic tubes

A thin wafer for cutting plastic tubes which are to be butt welded together includes a high temperature insulated plate-like core with a resistance circuit on the core for heating the wafer to a temperature sufficiently high to melt through the tubes. A glass layer may be on the outer surface of the water, particularly in the contact area with the tube. The wafer may be used in an arrangement wherein residue is removed from the water by having the residue adhere to unused portions or stubs of the tubes which then would be stripped from the wafer.

Hybrid welding wafer

Thermoplastic tubes are welded together in a dry condition with the tubes being open and maintained in their undistorted condition during the welding step. In an alternative technique a branch tube is welded to a main tube by placing the tubes in a non-parallel orientation in a holding device. A wafer cuts completely through one tube to form two tube sections. The wafer also cuts a notch from the other tube. One of the tube sections is shifted to become aligned with the notched other tube and welded thereto. A further technique includes placing at least one tube in a holding device which has a false floor for pressing against an area of the tube while the tube is being flattened at two spaced locations on opposite sides of the area. When the false floor is moved away from the tube a partial vacuum results. An air pocket is formed when the tube is severed by a wafer by air flowing into the cut tube.

A linear welding process and apparatus connects fluid-filled tubes in a sterile manner. The linear welder includes a base on which a carriage is slidably mounted. A pair of side by side arms are secured to the carriage as are a pair of tube holders. A pair of clamping jaws are mounted on the arms to clamp a pair of tubes in the holders. The arms are movable for passing the clamped tubes into contact with a heated wafer which cuts the tubes into tube sections. The tube sections are realigned and a pair of sections are butt welded together.

Sterile welding of plastic tubes

A process and system is provided for making a connection between two fluid-filled plastic tubes that ensures total containment of potentially dangerous fluids and maintaining sterility of the connection. The tubes are folded to remove all fluid from the weld site and positioned to cause the connection to take place in this fluid free zone. Each folded section is first cauterized to create a bacteria free zone, the tubes are slit in the zone, and cauterized a second time to insure sterility and melt the tube ends. The tubes are urged together and as the thermoplastic resin cools, a totally contained, sterile weld is formed.

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Wilmington, DE, United States of America

John B Shaposka