Heat Weld Tubing Connectors

Abstract

The present invention provides thermoplastic tubes, thermoplastic melting plates, thermoplastic tube connecting apparatus, and methods for using the same.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are a schematic, fragmentary longitudinal section view of a thermoplastic tube having a sealed end;

FIGS. 2A-2D are a schematic, longitudinal section view of various thermoplastic cap configurations;

FIGS. 3A-3G are schematic illustrations of various steps in connecting a first and a second thermoplastic tubes together transversely of the axis of each tube;

FIG. 3H is a transversal cross-sectional illustration of one of the thermoplastic tubes shown in FIG. 3D;

FIG. 4A is a schematic cross-sectional view of a thermoplastic melting plate and the thermoplastic tube;

FIGS. 4B and 4C are a side view of various thermoplastic melting plate configurations;

FIGS. 5A and 5B are cross-sectional view of a thermoplastic tube connecting apparatus comprising a thin film that is designed to prevent a direct contact between a hot plate and a thermoplastic tube;

FIG. 5C is a perspective view of a thermoplastic tube connecting apparatus of FIGS. 5A and 5B comprising a plurality of thermoplastic tube holders that can be used to simultaneously connect a plurality of thermoplastic tubes;

FIG. 6 is a schematic illustration of simultaneously connecting a plurality of thermoplastic tubes such as in platelet separation from buffy coats;

FIG. 7 is another schematic illustration of simultaneously connecting a plurality of thermoplastic tubes; and

FIG. 8 is a close-up cross-sectional view of a thermoplastic tube holder.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides various thermoplastic tubes, thermoplastic melting plates, thermoplastic tube connecting apparatus, and methods for using the same. Devices and methods of the present invention are particularly useful, although not necessary, in aseptic thermoplastic tube connection.

Some of the problems associated with conventional thermoplastic tube connecting methods are that the thermoplastic tube connection joints sometimes leak thus requiring carefully inspection and sometimes requiring the resulting products associated with the connection be discarded. Some of the methods and devices of the invention eliminate or greatly reduce the failure rate (i.e., leakage) of thermoplastic tube connection. Accordingly, methods and devices of the invention provide huge benefit to various medical procedures. For example, it is believed that in blood-banking applications in France, all thermoplastic tube connections made with currently available technology must be inspected, e.g., by pressurizing with air and holding the connected joint under water to check for leaks. Such inspection is time consuming. In addition, a significant amount of connected joints fail and have to be redone or the resulting products must be discarded, thereby adding to the overall cost and time, and loss of valuable blood materials. By eliminating or significantly reducing the failure rate, methods and devices of the invention significantly reduce the time and cost of connecting tubes.

The present invention will now be described with regard to the accompanying drawings which assist in illustrating various features of the invention. In this regard, the present invention generally relates to various devices and methods for connecting thermoplastic tube ends.

FIG. 1 is a schematic, fragmentary longitudinal section view of a thermoplastic tube having a sealed end. Two configurations are illustrated in FIGS. 1A and 1B. As can be seen in FIG. 1A, the distal end of the sealed end 180 comprises thermoplastic tube 100, which has an outer diameter 110 and an inner diameter 114. The thermoplastic tube 100 is inserted into and is hermetically sealed with a thermoplastic cap 150, which comprises the sealed end 180. The thermoplastic cap 150 has an outer diameter 160 and an inner diameter 164. The inner diameter 164 of thermoplastic cap 150 should be sufficiently large enough to accommodate thermoplastic tube 100 having the outer diameter 110. The inner diameter 164 of thermoplastic cap 150 should also be sufficiently small enough to form a hermetically sealed connection between thermoplastic tube 100 and thermoplastic cap 150.

In some embodiments, the inner diameter 164 of thermoplastic cap 150 is slightly smaller than the outer diameter 110 of thermoplastic tube 100 but is sufficiently large enough to allow insertion of thermoplastic tube 100 into thermoplastic cap 150, for example, by slightly expanding the inner diameter 164 with heat or by lubricating the outer surface of thermoplastic tube 100, for example, with a solvent thus forming a cohesive joint between thermoplastic components. Such configuration typically provides hermetically sealed connection between thermoplastic tube 100 and thermoplastic cap 150 without the need for any adhesive. Alternatively, when the inner diameter 164 is slightly larger than the outer diameter 110, an adhesive can be used to connect and/or hermetically seal thermoplastic tube 100 with thermoplastic cap 150. When an adhesive is used, such adhesive should be compatible with the desired application. Suitable adhesives include, but are not limited to, urethane adhesives, and solvent mediated adhesives.

FIG. 1B is a schematic illustration of one-piece longitudinal section view of a thermoplastic tube 100B having a sealed end 180B. In this embodiment, the inner diameter is relatively constant throughout, i.e., 114B and 164B are equal within the manufacturing limitation. However, the wall thickness defined by the difference between the outer diameter and the inner diameter is significantly different between the tube section distal to the sealed end and the tube section proximal to the sealed end. That is, the wall thickness defined by the difference between 160B and 164B is significantly higher than the wall thickness defined by the difference between 100B and 114B. Unless stated or the context requires otherwise, the term “proximal to the sealed end” refer to that portion of the thermoplastic tube having the wall thickness or the cross-sectional area that is substantially larger than the thermoplastic tube portion that is distal to the sealed end. Thus the terms “proximal” and “distal” are operational terms based on the wall thickness and/or the cross-sectional area of the tube. Unless stated or the context requires otherwise, the term “cross-sectional area” refers to the transversal cross-sectional area of the thermoplastic tube, i.e., cross-sectional area that is perpendicular to the longitudinal axis of the thermoplastic tube.

Referring again to FIGS. 1A and 1B, regardless of the configuration, in some embodiments, the outer diameter 160 that is proximal to the sealed end 180 is substantially greater than the outer diameter 110 that is distal to the sealed end 180. In addition, the wall thickness (defined by the difference between the outer diameter 160 and the inner diameter 164) proximal to the sealed end 180 is substantially greater than the wall thickness (defined by the difference in the outer diameter 110 and the inner diameter 114) distal to the sealed end 180.

Typically, thermoplastic tube 100 is flexible. However, it should be appreciated that the scope of the invention does not limit the thermoplastic tube 100 to be flexible. The material of thermoplastic tube 100, particularly the portion that is proximal to the sealed end 180, should be capable of becoming molten when heated. Conventional medical tubing materials, such as, but not limited to, thermoplastics, thermoplastic elastomers and PVC. Furthermore, the tubing can be co-extruded with a PVC core of higher melt temperature and an outer sleeve with similar melt temperature as compared to the cap component 150. The higher melt temperature core can allow a different melt flow characteristic to positively influence self-opening feature. In addition, the tubing can be co-extruded with a thermoplastic polyolefin core and thermoplastic outer sleeve allowing solvent bonding to the thermoplastic cap component 150. The polyolefin core can then allow a different melt flow characteristic to influence self opening. Moreover, the same property can be achieved using other thermoplastic resins co-extruded in a similar manner. Alternatively, the inverse can also be used where the co-extruded core can be a lower melt temperature thermoplastic ensuring a seal is formed in the center of the tubing that can be later opened if desired.

In some embodiments of the invention, thermoplastic cap 150 is used. Within such embodiments, in some instances both thermoplastic 100 and thermoplastic cap 150 have the same melting temperature. In other instances, thermoplastic cap 150 has a different melting temperature than thermoplastic tube 100. Within these instances, in some cases thermoplastic cap 150 has a higher melting temperature than thermoplastic tube 100. Still in other cases, thermoplastic cap 150 has a lower melting temperature than thermoplastic tube 100.

FIG. 2 illustrates a schematic, longitudinal section view of various thermoplastic cap configurations. Regardless of any particular configuration, thermoplastic cap 200 comprises an orifice 204 which is adapted for receiving a thermoplastic tube (not shown in FIG. 2) and a sealed end 280. The inner diameter of orifice 204 is adapted to receive and be hermetically sealed with the thermoplastic tube, when the thermoplastic tube is coupled with or connected to thermoplastic cap 200. In addition, thermoplastic cap 200 comprises channel 208 that is in fluid communication with orifice 204. Channel 208 may have the same inner diameter or a different inner diameter than the inner diameter of orifice 204. Thermoplastic cap 200 can also includes a wall 212 positioned between orifice 204 and channel 208. Wall 212 is adapted for providing a stopping point when a thermoplastic tube is inserted through orifice 204. However, it should be appreciated that a thermoplastic tube need not be inserted all the way to wall 212. All that is required is a sufficiently tight hermetic seal be formed between a thermoplastic tube and thermoplastic cap 200. As illustrated in FIG. 2, sealed end 280 can be of various shapes and configurations.

While the inner diameter of orifice 204 is typically larger than the inner diameter of channel 208, as illustrated in FIGS. 2A-C, in some embodiments, the inner diameter of orifice 204 is smaller than the inner diameter of channel 208. In this configuration, rather than inserting the thermoplastic tube to orifice 204, thermoplastic cap 200 is inserted into a thermoplastic tube. That is, the outer diameter of orifice 204 in FIG. 2D is such that it can be inserted into the thermoplastic tube and form a hermetic seal. Accordingly, the scope of the invention encompasses thermoplastic caps that receive a thermoplastic tube as well as thermoplastic caps that are inserted into a thermoplastic tube.

Optionally, thermoplastic cap 200 can also include a flange 216. Flange 216 can encompass the entire circumference of thermoplastic cap 200 or it can encompass only a portion of the circumference of thermoplastic cap 200. Flange 216 is useful for various purposes. For example, it can be used as a stopping point during melting of the sealed end 280 to form molten thermoplastic. That is, flange 216 can be used to allow formation of molten thermoplastic up to where flange 216 is located. Since the cross-section area of the thermoplastic is greater where flange 216 is located, joining of molten thermoplastic at flange 216 allows stronger joint connection as well as ease of joint formation due to its greater surface area for forming a joint connection. Furthermore, flange 216 can be used to aid in opening of the lumen after the thermoplastic tubes are connected. For example, one can use flange 216 to pull apart the lumen of connected thermoplastic tubes or the elasticity modulus associated with this flange could restore the lumen to the open condition following the joining of the tube ends.

Another aspect of the invention provides a method and devices for joining thermoplastic tubes in a sterile condition. In this aspect of the invention, thermoplastic tube configuration having a greater cross-sectional surface area proximal to the sealed end is provided. The present inventors have found that thermoplastics having a larger cross-sectional thermoplastic surface area allow stronger and/or easier connection between the thermoplastic tubes. Without being bound by any theory, it is believed that the ease, and/or reliability, of forming an airtight connection between thermoplastic tube ends is proportional to the cross-sectional thermoplastic surface area, i.e., thermoplastic tube ends having a larger cross-sectional thermoplastic surface area are easier to form reliable, strong and/or airtight connection. Accordingly, it is believed that the margin of error and/or the failure rate is inversely proportional to the cross-sectional thermoplastic surface area. Hence, some aspects of the invention reduce the margin of error for connecting thermoplastic tube ends by providing thermoplastic tube ends having a larger cross-sectional thermoplastic surface area relative to the conventional thermoplastic tubes that are typically used in forming a sterile connection. For example, conventional thermoplastic tubes that are used in medical procedures have inner diameter of about 0.16 inches with the cross-sectional thermoplastic area of about 6.2 mm² (0.6 mm wall thickness). By increasing the cross-sectional thermoplastic area to about 16 mm² (1.2 mm wall thickness) or to about 27 mm² (1.8 mm wall thickness), or to about 75 mm² (3.6 mm wall thickness), it has been found that a significantly stronger connection between thermoplastic tube ends can be formed. In addition, increasing the cross-sectional thermoplastic thickness also significantly reduces the rate of joint failure.

In one embodiment, a thermoplastic cap, such as those shown in FIG. 2 optionally having flange 216, is provided. As discussed above, the thermoplastic caps can be used to cap a conventional thermoplastic tube to provide a sealed end having a larger cross-sectional thermoplastic surface area. Alternatively, a thermoplastic cap such as those illustrated in FIG. 3 can be used to provide a larger cross-sectional thermoplastic surface area. It should be appreciated that thermoplastic caps in the accompanying Figures are for illustrative purposes only, and the scope of the invention includes any thermoplastic cap configuration that provides increased cross-sectional thermoplastic surface area and/or increased cross-sectional thermoplastic thickness.

One exemplary method for connecting a first and a second thermoplastic tubes together transversely of the axis of each tube is schematically illustrated in FIG. 3. In FIG. 3, the first thermoplastic tube 300 and the second thermoplastic tube 350 having thermoplastic caps 304 and 354 are shown. In this illustration, thermoplastic tubes 300 and 350 are inserted into and hermetically sealed with thermoplastic caps 304 and 354 to provide sealed ends 308 and 358, respectively. In this particular illustration, the thickness of thermoplastic caps 304 and 354 is substantially greater than the thickness of thermoplastic tubes 300 and 350. The cross-sectional thermoplastic surface area proximal to the sealed ends 308 and 358 is substantially greater than the cross-sectional surface area distal to the sealed end. In addition, the thermoplastic wall thickness is substantially greater proximal to the sealed end relative to the wall thickness distal to the sealed end.

For connecting first thermoplastic tube 300 with second thermoplastic tube 350, the sealed ends 308 and 358 are optionally, and preferably, compressed as shown in FIG. 3B. This compression closes the lumens (or tube interiors) 312 and 362 proximal to the sealed ends 308 and 358, respectively. Such closure prevents the lumen of tubes 300 and 350 from filling with molten thermoplastic while being pressed into the hot plate as described below. In addition, such closure also prevents the lumens from being exposed to the atmosphere and maintains the thermoplastic tubes in an aseptic condition. Additionally, such closure allows removal of interior contents from the molten thermoplastic preventing external leaks due to expanding tubing contents with rising temperature.

The sealed ends 308 and 358 are then heated, either by a direct contact with a heated plate 380 or by other heating means known to one skilled in the art (not shown), including non-direct contact means such as those discussed above. As shown in FIG. 3C, thermoplastic tubes are pressed into hot plate 380 in a direction shown by arrows A and B. This pressing of the thermoplastic tubes into hot plate 380 melts the thermoplastic at the sealed end to produce molten thermoplastic. It should be appreciated that the sealed ends 308 and 358 can optionally be cut using a cutting blade, which may be the same as hot plate 380, prior to producing molten thermoplastic. Preferably the cutting blade is heated to allow simultaneous cutting and melting of the thermoplastic. As used herein, the term “molten thermoplastic” refers to both melted thermoplastic as well as softened thermoplastic resin that is capable of adhering to other molten thermoplastic.

FIG. 3C shows molten thermoplastic 316 and 366 flowing away from the compressed lumens of thermoplastic tubes and caps. It should be appreciated that the likely contaminated surface portions 308 and 358 of caps 304 and 354 are the first portions of the cap to become molten. As the surface regions melt and flow away from the lumen, any contaminants contained thereon are effectively flushed or removed away from the lumen thus maintaining lumen sterility. In some embodiments of the invention, it is advantageous to produce excess molten thermoplastic 316 and 366 as shown in FIG. 3D. Excess molten thermoplastic flow further helps carry away from the lumen any contaminants that might have been on the surface of the tube or the cap. After producing molten thermoplastic, hot plate 380 is removed as shown in FIG. 3E, while maintaining airtight closure of interior of thermoplastic tubes 300 and 350. The molten ends are then contacted with one another as shown in FIG. 3F to form a joint between thermoplastic tubes 300 and 350. The thermoplastic tubes may optionally be further advanced in the direction of arrows A and B (see FIG. 3C), thus producing additional molten thermoplastic flow and purging the molten surfaces of any air born contaminant that may have landed on the molten surface following removal of hot plate 380. When excess molten thermoplastic 316 and 366 is present, the resulting joint between thermoplastic tubes 300 and 350 may include flange 330. When excess molten thermoplastic is present, it provides a greater surface area for forming a connecting joint. As discussed above, the greater surface area reduces the rate of joint failure as well as providing a stronger and/or easier joint formation.

After joining the molten thermoplastic ends together, the external force (e.g., clamp) is removed allowing the lumen to regain its original shape. See, for example, FIG. 3G. In some embodiments, the thermoplastic wall proximal to the sealed end has a sufficient elasticity modulus to open the interconnecting lumen without a need for any external force. Generally the required elasticity modulus is a result of the thermoplastic tube's wall thickness and relatively low melting temperature as compared to the sealed end. In other embodiments, flange 330 can be used to aid in opening the lumen, e.g., by pulling flange 330 away from the lumen or by virtue of the elasticity modulus of the flange and/or the thermoplastic tubes themselves. In other embodiments, elastic modulus of flange 216 maybe used to open the lumen without any external force.

FIG. 3H is a transversal cross-sectional view of thermoplastic tube 300 shown in FIG. 3D. During its contact with hot plate 380 (not shown in FIG. 3H, but see FIG. 3D), molten thermoplastic is produced proximal to the sealed end 308. As thermoplastic tube 300 is pressed into hot plate 380, molten thermoplastic flows away from the interior of thermoplastic tube 300. Such molten thermoplastic flow maintains aseptic condition of the interior of thermoplastic tube 300. Generally, when excess molten thermoplastic flow is used, the surface area of the molten thermoplastic is at least about 100% greater, preferably at least about 250% greater, and more preferably at least about 500% greater, than the cross-sectional area of the sealed end. In one particular example, when excess molten thermoplastic flow is used, the surface area of the molten thermoplastic is from about at least 200% to about 800% greater than the cross-sectional area of the sealed end.

Suitable thermoplastic tube connecting apparatuses are well known to one skilled in the art and include, but are not limited to, those discussed in the Background of the Invention section as well as U.S. Pat. Nos. 6,341,637; 6,026,882; 6,679,529; 6,913,056; 4,443,215; 4,412,835; 4,507,119; 5,345,070; and PCT Publication Nos. WO 82/02528; and WO 02/087491, all of which are incorporated herein by reference in their entirety.

In conventional thermoplastic tube connecting apparatuses that use a thermoplastic melting plate, the surface area of the thermoplastic melting plate that is heated during operation is significantly larger than the area needed to produce molten thermoplastic from the thermoplastic tube. This results in a significantly higher energy requirement than necessary since the excess heat dissipates from the heated surface area of the thermoplastic melting plate without being used.

Accordingly, another aspect of the present invention provides a thermoplastic melting plate that is designed to significantly reduce or eliminate unnecessary heat consumption during its operation. In some embodiments, a thermoplastic melting plate that is adapted to be used with a heat weld thermoplastic tube connecting apparatus is provided. FIGS. 4A-4C illustrate some embodiments of the thermoplastic melting plate of the invention. As can be seen, the thermoplastic melting plate 400 comprises a heat transferring material 404 that is adapted for melting a thermoplastic tube to produce molten thermoplastic. As used herein, the term “heat transferring material” refers to any material of a component of an apparatus that is used to produce molten thermoplastic from the thermoplastic. In addition, thermoplastic melting plate 400 comprises a front surface 408A; a back surface 408B; an insulating material 412 substantially covering front surface 408A and back surface 408B; an exposed heat transferring material portion (416A and 416B in FIGS. 4A and 416 in FIGS. 4B and 4C) within the insulating material 412 such that the exposed heat transferring material portions are adapted for melting the thermoplastic tube 450 and the thermoplastic cap 454 to produce molten thermoplastic; and an interface portion 420 for operatively connecting thermoplastic melting plate 400 to a heat weld thermoplastic tube connecting apparatus (not shown). Typically, interface portion 420 is adapted to be operatively connected to a heating element of the heat weld thermoplastic tube connecting apparatus (not shown).

The thermoplastic melting plate can be made of any material that can conduct heat. Exemplary materials that are suitable for thermoplastic melting plates include metals, heat transferring ceramics, metal alloys, as well as other materials that are known heat conductors, such as a flash heater available from Watlow Electric Manufacturing Company (St. Louis, Mo.). In one specific embodiment, the thermoplastic melting plate is adapted for use with tube connecting apparatuses such as the Terumo Sterile Tubing Welder, Model SC-201A (available from Terumo Medical Corp. Somerset, N.J., U.S.A.). In one embodiment, the thermoplastic melting plate is a thin plate that can optionally be used to both heat and cut thermoplastic tubes.

In other embodiments, the thermoplastic melting plate can be a thin plate that is sized to correspond to the area to be sealed. Such a plate does not need to have any insulating material and can heat and cool very rapidly due to its thinness.

In other embodiments, thermoplastic melting plates of the invention are adapted to be useful in any thermoplastic connecting apparatus that is schematically illustrate in FIG. 3 as well as those that do not require a direct contact to produce molten thermoplastic. As will be recognized, in embodiments where the thermoplastic tube is not directly contacted to the thermoplastic melting plate, the thermoplastic melting plate is heated to a temperature sufficient to melt the thermoplastic tube when it is placed near the thermoplastic melting plate.

The insulating material, when used, substantially covers the portion of the thermoplastic melting plate that is not used in thermoplastic tube connection operation. In one embodiment, the insulating material comprises aluminum silicate, a heat insulating ceramic, or a combination thereof.

In some embodiments, the thermoplastic melting plate can also be used to cut the thermoplastic tube. In such embodiments, the thermoplastic melting plate comprises an edge 424 (see FIG. 4B) that is sufficiently shaped when heated to cut a thermoplastic tube.

Another aspect of the invention provides a thermoplastic tube connecting apparatus comprising the thermoplastic melting plate disclosed herein.

One of the problems associated with a hot plate thermoplastic tube connection apparatus is the potential for degraded plastic and/or molten plastic to build up on the hot plate. In some cases, such problem is eliminated by using a disposable hot plate. However, this solution adds to the overall cost and time for connecting thermoplastic tubes by requiring the hot plate to be replaced after each operation.

Accordingly, another aspect of the present invention provides a device and a method for eliminating degraded plastic and/or molten plastic from building up on the hot plate without a need for using a disposable hot plate. As illustrated in FIGS. 5A and 5B, one embodiment of such a thermoplastic tube connecting apparatus comprises a thermoplastic melting plate 500 that is adapted for melting a thermoplastic tube (504A and 504B) thereby producing a molten thermoplastic tube end; and a thin film 508 that is adapted for being placed between the thermoplastic tubes 504A and 504B, and the thermoplastic melting plate 500 such that the thermoplastic tubes do not come in direct contact with thermoplastic melting plate 500 during its operation.

Thin film 508 can be comprised of any material that readily conducts heat and is sufficiently strong enough to withstand tear during operation. When thin film 508 is used, thermoplastic melting plate 500 should not have any sharp edges as any sharp edge may tear thin film 508. Accordingly, in some embodiments, thermoplastic melting plate 500 has a rounded dull edge which reduces the risk of causing any tear of thin film 508. Exemplary materials that are suitable for thin film 500 include, but are not limited to, thin malleable metallic sheets (such as aluminum foil and copper foil), polytetrafluoroethylene, polyester, Q Foil (available from EGC Enterprises Inc., Chardon, Ohio), and a combination thereof.

The thermoplastic tube connecting apparatus can also include a roller, a drum, a cartridge, or other mechanical means known to one skilled in the art that allows a different portion of thin film 508 to come in contact with thermoplastic tubes during subsequent thermoplastic tube connecting operations. Such mechanism is schematically represented as item 512 in FIGS. 5A and 5B. The amount of thin film 508 advancement during each thermoplastic tube connection operation can be controlled by a computer (not shown) or it can be controlled by a mechanical means such as a sprocket or a gear mechanism that is spaced according to the amount of thin film 508 advancement desired. Alternatively, friction based rollers can be used to advance the desired amount of thin film 508. Another method is to provide a plurality of sprocket drive holes (not shown) near the edge of thin film 508. Such sprocket drive holes can be precision punched to maintain a uniform spacing and to allow proper advancement of thin film 508 with each thermoplastic tube connection operation using, for example, tractor drive mechanism (not shown).

Regardless of the mechanism used, each thermoplastic tube connection operation allows a fresh new surface area of thin film 508 to come in contact with thermoplastic tubes, thereby preventing any direct contact between thermoplastic melting plate 500 and thermoplastic tubes 504A and 504B. Such operation prevents any build up of degraded plastic and/or molten plastic on hot plate 500 and provides a clean surface for thermoplastic melting without the need for using a disposable thermoplastic meting plate.

The thermoplastic tube connecting apparatus can also include one or more guides 516 that are adapted to allow thermoplastic hot plate 500 to be properly positioned and allow thin film 508 to be operatively connected to thermoplastic hot plate 500. Guide 516 can be a separate roller, drum, or other mechanical device known to one skilled in the art. Alternatively, guide 516 can be part of a thermoplastic tube holder as discussed in detail below.

As shown in FIG. 5C, thermoplastic tube connecting apparatus of the invention can comprise a thermoplastic tube holder 520 that can hold a plurality of thermoplastic tubes (or a plurality of thermoplastic tube holders). This configuration allows simultaneous connection of a plurality of thermoplastic tubes. This is particularly useful with the thermoplastic tube connecting apparatus that comprises a thin film 508 which eliminates a need for disposable thermoplastic melting plate and/or the direct contact between thermoplastic melting plate 500 and thermoplastic tubes 504A and 504B. In FIG. 5C, thermoplastic tube holder 520 can also serve as a guide that allows thermoplastic hot plate 500 to be properly positioned.

Although FIG. 5C shows a single thermoplastic melting plate 500 with thin film 508, it is understood that multiple tube connections can be made with a plurality of thin thermoplastic melting plates, wherein each plate is associated with a pair of the multiple tube connections.

Achieving simultaneous multiple thermoplastic tube connection is advantageous in various medical procedures compared to the conventional sterile thermoplastic tube connection methods that use a single costly disposable blade for each connection. As shown in FIGS. 6 and 7, use of thin film 608 and 708, respectively, eliminates the need for replacing the hot plate 600 and 700, respectively, after each tube connection operation. In part, thin film 608 and 708 prevents molten tubing plastic from adhering to hot plate 600 and 700, respectively. FIGS. 6 and 7 illustrate simultaneous multiple tube connection that can be used in various medical procedures, for example, for removing platelets from buffy coats previously separated from whole blood. One example of currently available apparatus for removing platelets is the Orbisac System available from Gambro BCT, Inc. (Lakewood, Colo., USA). Buffy coat, produced from a whole blood donation, is a combination of platelets and white blood cells, as well as small amounts of red blood cells and plasma.

As a brief background, in the mid-1970's, European blood centers began to remove the buffy coat from separated red blood cells. It was discovered that the buffy coat contained a high concentration of platelets, a blood component vital to blood clotting.

The majority of platelets collected during a whole blood donation are found in the buffy coat layer, which settles between red blood cells and plasma during centrifugation. To extract as many of these platelet as possible, buffy coats are pooled from many donations and re-spun in a centrifuge to separate the platelets from the rest of the buffy coat. The platelets collected contain some white blood cells even after centrifugation, so the platelets are filtered to remove white blood cells before storage and transfusion. This process is called leukoreduction.

Platelets help the blood to clot. People with certain diseases like thrombocytopenia, leukemia, and other cancers have a reduced number of platelets in their bloodstreams. Without adequate platelets, they bleed abnormally and bruise easily. Regular platelet transfusions are essential treatment for these and other patients. Typically, the process to create pooled, leukoreduced platelets from whole blood is time-consuming, labor-intensive and requires many manual steps.

Processing whole blood buffy coat platelets requires multi-step, post-donation processes: pooling, centrifugation, expression, and filtration. These manual processes are labor-intensive and time consuming. As expected, anytime a task is performed manually, there is an increased risk of processing errors. Whole blood donations are separated into components via gravitational force in a centrifuge. The force of the centrifuge causes the whole blood to separate into layers based on cell density. The upper layer captured in the centrifuge is plasma. The middle layer is the buffy coat. The bottom, heaviest layer is packed red blood cells. There are various automated apparatuses to perform the buffy coat processing steps, such as the Orbisac System. Typically, these apparatuses perform various tasks, such as pooling, centrifugation, expression, and filtration.

Some embodiments of the thermoplastic tube connecting apparatus of the invention allow simultaneous multiple thermoplastic tube connection, such as those useful in collecting platelets and processing buffy coats pooled from many blood donations. As shown in FIG. 6, five (5) different bags (604A to 604E) each containing buffy coat are simultaneously connected to a centrifuge bag 650 used in combination with the Orbisac System, using hot plate 600 and a thin film 608 as described herein. In addition, a bag containing platelet storage solution or plasma 612 is also simultaneously connected to the centrifuge device 650. Thermoplastic tubes from bags 604A-604E and 612 are placed such that they are properly positioned for connection, see for example FIG. 5C. It should be appreciated that some devices may require the bags be connected in series such as that depicted in FIG. 7. A tube holder (520 in FIGS. 5C and 800 in FIG. 8), which optionally, and preferably, clamps and closes the lumen, holds the thermoplastic tubes (504 in FIGS. 5C and 804 in FIG. 8) in proper position. The tube holder (520 in FIGS. 5C and 800 in FIG. 8) also moves tubing ends against an optionally thin film 508 covered hot plate 500 to produce molten thermoplastic tube ends. After removing the hot plate 500, the tube holder 520 moves the molten thermoplastic tube ends together to form joint connections. A tubing manifold 624 connects the plurality of thermoplastic tubes 628A-628F to the centrifuge bag (or other container) 650.

After connecting buffy coat bags 604A-604E to tubing manifold 624, buffy coats, along with the storage solution, are pooled in the centrifuge bag 650 and the platelets are separated from the rest of the buffy coat. The collected platelets are then transferred to platelet storage bag 612 and then optionally filtered to further remove white blood cells.

Alternatively, as shown in FIG. 7, a platelet storage solution bag 712 and a plurality of buffy coat bags (e.g., 716A-716E) are connected as shown using the thermoplastic tube connecting apparatus of the invention. Formation of such plurality tubing connections are described herein. In FIG. 7, buffy coats are pooled in to a centrifuge bag 720. The contents of bag 720 is then centrifuged, e.g., in a conventional bucket centrifuge, to separate the platelets (centrifuge step not shown). The collected platelets are again optionally filtered to further remove white blood cells and are then transferred to a storage bag 724. Unlike the process illustrated in FIG. 6, process of FIG. 7 does not require a tubing manifold 624.

Additional objects, advantages, and novel features of this invention will become apparent to those skilled in the art upon examination of the following examples thereof, which are not intended to be limiting.

The foregoing discussion of the invention has been presented for purposes of illustration and description. The foregoing is not intended to limit the invention to the form or forms disclosed herein. Although the description of the invention has included description of one or more embodiments and certain variations and modifications, other variations and modifications are within the scope of the invention, e.g., as may be within the skill and knowledge of those in the art, after understanding the present disclosure. It is intended to obtain rights which include alternative embodiments to the extent permitted, including alternate, interchangeable and/or equivalent structures, functions, ranges or steps to those claimed, whether or not such alternate, interchangeable and/or equivalent structures, functions, ranges or steps are disclosed herein, and without intending to publicly dedicate any patentable subject matter.

Claims

1. A thermoplastic tube comprising: an inner diameter,an outer diameter; anda sealed end,

2. The thermoplastic tube of claim 1, wherein the wall thickness proximal to said sealed end is at least about 25% greater than the wall thickness distal to said sealed end.

3. The thermoplastic tube of claim 1, wherein the wall thickness proximal to said sealed end is at least about 0.7 mm.

4. The thermoplastic tube of claim 1, wherein said sealed end comprises a thermoplastic cap having inserted therein said thermoplastic tube such that said thermoplastic tube and said thermoplastic cap are hermetically sealed to form said sealed end.

5. The thermoplastic tube of claim 4, wherein said thermoplastic cap comprises a flange.

6. The thermoplastic tube of claim 4, wherein said thermoplastic cap has a different melt temperature than said thermoplastic tube distal to said sealed end.

7. The thermoplastic tube of claim 4, wherein said thermoplastic cap has the same melt temperature as said thermoplastic tube distal to said sealed end.

8. The thermoplastic tube of claim 4, wherein the inner portion of said thermoplastic tube has a different melt temperature than the outer portion of said thermoplastic tube.

9. The thermoplastic tube of claim 1 further comprising a flange proximal to said sealed end.

10. The thermoplastic tube of claim 1 further comprising a sealed vessel that is in combination with said sealed end.

11. The thermoplastic tube of claim 10, wherein said sealed vessel is a plastic bag.

12. A thermoplastic cap adapted to provide a sealed thermoplastic tube end when a thermoplastic tube is positioned and hermetically sealed with said thermoplastic cap, said thermoplastic cap comprising: an orifice for receiving the thermoplastic tube, wherein the diameter of said orifice is adapted to be hermetically sealed with the thermoplastic tube when the thermoplastic tube is coupled with said thermoplastic cap;a channel in fluid communication with said orifice and having a different diameter than the diameter of said orifice;a wall positioned between said orifice and said channel such that it is adapted for providing a stopping point during a process for joining the thermoplastic tube with said thermoplastic cap; anda sealed end distal to said orifice.

13. The thermoplastic cap of claim 12 further comprising a flange on the outer surface of said thermoplastic cap.

14. A method for connecting first and second thermoplastic tubes together transversely of the axis of each tube comprising: forming molten thermoplastic ends from first and second thermoplastic tubes, wherein each of the first and the second thermoplastic tubes comprises:an inner diameter defining a lumen,an outer diameter; anda sealed end,wherein the cross section defined by said outer diameter is substantially greater proximal to said sealed end relative to the cross section distal to said sealed end, and wherein the wall thickness defined by said inner and outer diameter is substantially greater proximal to said sealed end relative to the wall thickness distal to said sealed end; andmoving the respective molten ends of the thermoplastic tubes together to form a joint between the first and the second thermoplastic tubes.

15. The method of claim 14, wherein said step of forming molten thermoplastic ends comprises contacting each of the sealed ends to a heat transferring material that is heated to a temperature at least equal to the melt temperature of the thermoplastic ends.

16. The method of claim 14, wherein said step of forming molten thermoplastic ends comprises heating each of the sealed end to temperature at least equal to the melt temperature of the thermoplastic ends.

17. The method of claim 14 further comprising substantially flattening the sealed end of each thermoplastic tube such that the lumen at a position to be connected is substantially closed prior to said step of forming molten thermoplastic ends.

18. The method of claim 17 further comprising opening the lumen after forming the joint between the first and the second thermoplastic tubes.

19. The method of claim 15, wherein said step of contacting the thermoplastic tubes to the heat transferring material further comprises providing means for having molten thermoplastic flow substantially away from the lumen of each tube.

20. A method for forming a sterile connection between a first thermoplastic tube and a second thermoplastic tube each comprising a sealed end, said method comprising: forming a molten thermoplastic end from each sealed end of the first and the second thermoplastic tubes such that the surface area of the molten thermoplastic is a greater than the cross-sectional area of the sealed end; andmoving the respective molten ends of the thermoplastic tubes together to form a joint between the first and the second thermoplastic tubes such that the joint comprises a flange formed from bonding of the molten thermoplastic from the first and the second thermoplastic tubes.

21. The method of claim 20, wherein the surface area of the molten thermoplastic is at least equal to the cross-sectional area of the sealed end.

22. The method of claim 20 further comprising substantially flattening the sealed end of each thermoplastic tube such that the lumen at a position to be connected is substantially closed prior to said step of forming molten thermoplastic ends.

23. The method of claim 20, wherein said step of forming molten thermoplastic ends comprises contacting each sealed end of the first and the second thermoplastic tubes to a hot plate thereby melting the sealed end to form the molten thermoplastic end.

24. The method of claim 23, wherein said step of contacting the thermoplastic tubes to the heat transferring material further comprises providing means for having molten thermoplastic flow substantially away from the lumen of each tube.

25. A method for forming a sterile connection between a first thermoplastic tube and a second thermoplastic tube each comprising a sealed end, said method comprising: forming a molten thermoplastic end from each sealed end of the first and the second thermoplastic tubes; andmoving the respective molten ends of the thermoplastic tubes together to form a joint between the first and the second thermoplastic tubes such that the joint comprises a flange formed from bonding of the molten thermoplastic from the first and the second thermoplastic tubes, wherein said step of moving the respective molten ends together results in the cross sectional area of the sealed end to be substantially greater than the cross sectional area of the walls of the tube proximal to the sealed end.

26. A method for connecting first and second thermoplastic tubes together transversely of the axis of each tube without a need for an external force to open an interconnecting lumen, said method comprising: forming molten thermoplastic ends from first and second thermoplastic tubes, wherein each of the first and the second thermoplastic tubes comprises:an inner diameter defining a lumen,an outer diameter; anda sealed end,wherein the wall thickness defined by said inner and outer diameter proximal to said sealed end has a sufficient elasticity modulus to open an interconnecting lumen after the tubes have been connected; andmoving the respective molten ends of the thermoplastic tubes together to form a joint between the first and the second thermoplastic tubes; andallowing the interconnecting lumen to open.

27. The method of claim 26, wherein the wall thickness of the cross-sectional area proximal to the sealed end is at least about 0.7 mm.

28. A thin thermoplastic melting plate adapted to be used with a heat weld thermoplastic tube connecting apparatus, said thermoplastic melting plate comprising a heat transferring material that is adapted for melting a thermoplastic tube to produce molten thermoplastic, wherein said thermoplastic melting plate comprises: a front surface;a back surface;an insulating material substantially covering said front and back surfaces;an exposed heat transferring material portion within said front and said back surfaces of said insulating material such that said exposed portion is adapted for melting the thermoplastic tube to produce molten thermoplastic; andan interface portion for operatively connecting said thermoplastic melting plate to the heat weld thermoplastic tube connecting apparatus.

29. The thermoplastic melting plate of claim 28, wherein said insulating material comprises aluminum silicate, a heat insulating ceramic, or a combination thereof.

30. The thermoplastic melting plate of claim 28, wherein said exposed heat transferring material portion is adapted for contacting the thermoplastic tube to produce molten thermoplastic.

31. The thermoplastic melting plate of claim 28, wherein said exposed heat transferring material portion is adapted to produce molten thermoplastic from the thermoplastic tube without contacting the thermoplastic tube.

32. The thermoplastic melting plate of claim 28, wherein said interface portion is adapted to be operatively connected to a heating element of the heat weld thermoplastic tube connecting apparatus.

33. A thermoplastic tube connecting apparatus comprising a removably attached thin heat transferring material that is adapted for melting a thermoplastic tube to generate a molten thermoplastic tube end, wherein said thin heat transferring material comprises: a front surface;a back surface;an insulating material substantially covering said front and back surfaces;an exposed heat transferring material portion within said front and said back surfaces that is adapted for melting the thermoplastic tube to produce a molten thermoplastic tube end; andan interface portion for operatively connecting said thermoplastic melting plate to a heat weld thermoplastic tube connecting apparatus.

34. The thermoplastic melting plate of claim 33, wherein said exposed heat transferring material portion is adapted for contacting the thermoplastic tube to produce molten thermoplastic.

35. The thermoplastic melting plate of claim 33, wherein said exposed heat transferring material portion is adapted to produce molten thermoplastic from the thermoplastic tube without contacting the thermoplastic tube.

36. The thermoplastic tube connecting apparatus of claim 33 wherein said interface portion is adapted to be operatively connected to a heating element of the heat weld thermoplastic tube connecting apparatus.

37. The thermoplastic tube connecting apparatus of claim 33 wherein said thin heat transferring material is adapted for melting a plurality of thermoplastic tubes to simultaneously generate a plurality of molten thermoplastic tube ends.

38. A thermoplastic tube connecting apparatus comprising: a thermoplastic melting plate that is adapted for melting a thermoplastic tube thereby producing a molten thermoplastic tube end; anda thin film that is adapted for being placed between the thermoplastic tube and said thermoplastic melting plate such that the thermoplastic tube does not come in a direct contact with said thermoplastic melting plate during its operation.

39. The thermoplastic tube connecting apparatus of claim 38, wherein said thin film comprises polytetrafluoroethylene, a metallic foil, or a combination thereof.

40. The thermoplastic tube connecting apparatus of claim 38 further comprising a means for allowing a different portion of the thin film surface to come in contact with each thermoplastic tube connection operation.

41. The thermoplastic tube connecting apparatus of claim 38 further comprising a thin film traversing element for traversing said thin film relative to said thermoplastic melting plate thereby allowing different area of the thin film to be contacted with the thermoplastic tube during each thermoplastic tube connection operation.

42. The thermoplastic tube connecting apparatus of claim 38, wherein said apparatus is adapted for simultaneously melting a plurality of thermoplastic tubes to generate a plurality of molten thermoplastic tube ends.

43. A method for connecting first and second thermoplastic tubes together transversely of the axis of each tube comprising: contacting the first and the second thermoplastic tubes to a thin film that is operatively connected to a thermoplastic melting plate to generate molten first and second thermoplastic tube ends; andmoving the respective molten ends of the thermoplastic tubes together to form a joint between the first and the second thermoplastic tubes.

44. The method of claim 43, further comprising traversing the thin film relative to the thermoplastic melting plate thereby allowing different area of the thin film to be contacted with the thermoplastic tube during each thermoplastic tube connection operation.