Sterile Connector and Method

This invention pertains to a connector and method for joining two conduits together in a sterile manner to permit aseptic fluid transfer between the conduits.

In the medical field, and in other fields, it is often necessary to transfer fluids between two closed systems without contamination by any extraneous matter including microbial bacteria and airborne contaminants. This need arises, for example, in the handling of blood and its components, as well as in other medical situations such as attachments to heart-lung machines and kidney-dialysis machines.

Heretofore, there have been numerous attempts to provide sterile connections, but these prior attempts have been subject to certain limitations and disadvantages such as complexity and cost, impeded flow between the two systems, and less than complete absence of contamination. Examples of such prior techniques are found in U.S. Pat. Nos. 3,865,411, 3,909,910, 4,022,256, 4,157,723, 4,187,846, 4,265,280, 4,325,417 and 4,340,097.

It is in general an object of the invention to provide a new and improved sterile connector and method for joining two conduits together to permit aseptic fluid transfer between the conduits.

Another object of the invention is to provide a connector and method of the above character which overcome the limitations and disadvantages of sterile connectors heretofore provided.

Another object of the invention is to provide a connector and method of the above character which are economical and easy to use.

These and other objects are achieved in accordance with the invention by providing the terminal ends of the conduits to be connected together with end caps of a material which melts and flows at a sterilizing temperature. These end caps are inserted into a sleeve, with the passageways in the conduits aligned axially and the end walls of the caps facing each other in confronting relationship. The end caps and the sleeve are heated to the sterilizing temperature to melt the end caps and draw the material from the end walls out of the region between the passageways. The molten material cools and hardens to form a permanent bond between the conduits.

FIG. 1 is a centerline sectional view of one embodiment of a sterile connector according to the invention, with the parts separated prior to connection.

FIG. 2 is a view similar to FIG. 1, with the parts in position to be bonded together.

FIG. 3 is a view similar to the other figures, with the parts bonded together and communication established between the conduits thus connected .

In the drawings, the invention is illustrated in connection with a pair of conduits 11 in the form of flexible plastic tubes connected to sterile containers (not shown) such as blood bags. Rigid tubular members 12 are connected to the terminal ends of the flexible tubes in a fluid-tight manner, for exampmle by stretching the end portions of the tubes over the tubular members. End caps 13 having side walls 14 and end walls 16 are mounted on the free ends of the tubular members to seal the containers at the terminal ends of the tubes. A rigid cylindrical sleeve 18 is fitted over one of the tubular members with the side wall of the end cap being positioned between the outer wall of the tubular member and the inner wall of the sleeve. The sleeve is about three times as long as the side wall of the end cap, and it projects axially from the tubular member on which it is mounted to receive the other tubular member in a like manner when the parts are joined together.

End caps 13 are fabricated of a thermoplastic material which melts and flows at a sterilizing temperature which is sufficient high to kill thermophilic bacteria. The sterilizing temperature is preferably on the order of 300.degree. C. or more, and one suitable material for the end caps is polyethylene. Tubular members 12 and outer sleeve 18 are fabricated of a material which does not melt at the sterilizing temperature, and it is also preferable that these parts to be fabricated of a material which is transparent to gamma rays commonly used in the sterilization of medical appliances. In one presently preferred embodiment, the tubular members and the sleeve are fabricated of Pyrex glass.

Operation and use of the connector, and therein the method of the invention are as follows. Prior to being joined together, end caps 13 seal the containers and conduits to which they are connected. To join the conduits together, the free ends of tubular members 12 are inserted into sleeve 18, with the flow passageways in the tubes being aligned axially and the end walls of the end caps facing each other in confronting relation within the sleeve. Prior to connection, sleeve 18 can either be attached to one of the tubular members or it can be kept separately and installed on both of the tubular members at the time of connection. with both of the tubular members inserted into the sleeve, the connection is made by applying heat to the outer surface of the sleeve to melt the plastic caps therein. The molten plastic from the end walls of the caps flows out of the region between the passageways in the tubular members and is drawn by capillary action into the region between the outer walls of the tubular members and the inner wall of the sleeve, thereby opening the passageway between the two conduits. The plastic material from the end walls combines with the plastic material from the side walls of the end caps, and the mass of plastic material 19 bonds the tubular members and the sleeve together as it cools and hardens, thereby joining the two conduits together in a permanent manner. The melting and flowing of the plastic material also serves to kill any bacteria which may be present on the outer surface of the end caps. The sterilizing temperature kills the bacteria, and any contamination on the end walls becomes embedded in the molten plastic and is carried out of the passageway formed between the tubes.

In applications where the conduits to be joined together are fabricated of a material which does not melt at the sterilizing temperature, tubular members 12 can be omitted, and end caps 13 can be mounted directly on the free ends of the conduits, in which case the ends of the conduits themselves are inserted into sleeve 18 to form the connection.

The invention has a number of important features and advantages. It is economical and easy to use. The passageways in the conduits which are joined together are aligned axially of each other to provide a substantially less impaired flow than prior art connectors in which the passageways are offset and the connection is made through a side wall. In addition, the melting and flowing of the plastic end caps serves to kill bacteria and to embed contaminants in the melted plastic and carry the embedded contaminants away from the sterile passageway of the connector.

It is apparent that a new and improved connector and method have been provided for joining conduits together in a sterile manner to permit aseptic fluid transfer between the conduits. While only certain presently preferred embodiments have been described in detail, as will be apparent to those familiar with the art, certain changes and modfications can be made without departing from the scope of the invention as defined by the following claims.