Apparatus for stripping fluid from flexible plastic tubing

BACKGROUND OF THE INVENTION

Blood is often collected from a donor using a plastic blood collecting and dispensing bag having a flexible plastic tubing integral therewith which communicates with the interior of the bag on its inner end. Such blood collecting devices are disclosed in U.S. Pat. No. 2,955,595. The bag is normally partially filled initially with an anticoagulant solution, which may also contain a preservative. This solution prevents the collected blood from clotting and also aids in preserving the blood when a preservative is present. The integral flexible plastic tubing is provided with a hollow needle on the outer end thereof for inserting into a vein of the donor, thereby allowing blood to flow from the donor, through the passage in the needle and plastic tubing, and into the interior of the bag. After the bag has been filled with a desired amount of blood to constitute a unit (usually 300 -500 ml.), the tubing is sealed by means of a knot formed therein near the needle, and the needle is removed and discarded.

After filling the bag, the tubing is filled with blood which, after sealing the tube into segments, is used for blood grouping, Rh typing and other studies such as disclosed in U.S. Pat. No. 2,955,595. However, the blood in the tubing has not been mixed with the solution in the bag. In order to prevent the blood in the tubing from coagulating and to preserve it, the fresh blood is allowed to flow from the tubing into the interior of the bag, mixed with the solution, and then the mixture which includes the blood and the anticoagulant and/or preservative is allowed to flow back into the tubing. This must be repeated several times in accordance with prior art practices to assure complete mixing of the blood and prevent coagulation in the tubing. The tubing, which is thermoplastic, is then sealed into segments by application of heat to provide a series of blood samples for test purposes.

It is apparent from the foregoing that the blood must be substantially completely removed from the tubing and mixed with the contents of the bag in order to prevent its coagulating in the tubing. However, prior to the present invention, an entirely satisfactory apparatus and method have not been available for accomplishing this in a rapid and efficient manner. Thus, when the blood was partially stripped from the tubing using the ineffective prior art means for this purpose and then allowed to flow back into the tubing, in many instances there was sufficient unmixed blood in one or more of the segments of the tubing to cause coagulation even after repeating the stripping and mixing procedure a number of times.

There are numerous other instances where fluids must be completely stripped from flexible plastic tubing. The fluids may be liquids such as water, saline solution, or glucose solution, or gases such as nitrogen or oxygen.

SUMMARY OF THE INVENTION

The present invention provides an improved apparatus for substantially completely stripping fluids from a flexible plastic tubing.

In a preferred variant, the invention further provides an improved apparatus for substantially completely stripping blood from a flexible plastic tubing which is integral with a blood collecting and dispensing bag that contains an anticoagulant solution and/or preservative.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view in elevation illustrating one embodiment of the fluid stripper of the invention and its use in connection with stripping fluid from a plastic tubing integral with a plastic fluid collecting and dispensing bag;

FIG. 2 is a cross-sectional view in elevation taken along the lines 2—2 of FIG. 1.

FIG. 3 is a view in elevation illustrating the stripping apparatus of FIG. 1, with the exception of the plastic tubing and the collecting and dispensing bag being omitted for purposes of clarity and the top and bottom hinged halves of the apparatus being swung to an open position to more clearly illustrate the cooperating component elements thereof;

FIG. 4 is a side view in elevation of a second preferred embodiment of the fluid stripper of the invention with the hinged top half being shown in the open position to more clearly illustrate the cooperating elements thereof;

FIG. 5 is a plan view of the apparatus of FIG. 4 with the hinged top half being illustrated in the closed position, and with end portions of the top roller being broken away to illustrate the manner of mounting the same.

FIG. 6 is a cross-sectional view in elevation taken along the line 6—6 of FIG. 5;

FIG. 7 is a rear view in elevation of the apparatus of FIG. 4 with the hinged top half being illustrated in the closed position;

FIG. 8 is a front view in elevation, with portions thereof being broken away, of the apparatus of FIG. 4 with the hinged top half being illustrated in THE closed position; and

FIG. 9 is a rear view in elevation, with portions thereof broken away, of the apparatus of FIG. 4, with the hinged top half being illustrated in the closed position and the top roll axis being adjusted so that the cooperating roll surfaces are angularly disposed to provide for variable tension on the tubing at spaced points along the length thereof.

Referring now to FIGS. 1-3 of the drawings, the stripping apparatus generally designated as 10 includes hinged halves 11 and 12 which are joined together by means of a pair of hinges 14. The halves 11 and 12 have a generally U-shaped configuration, and include flat portions 15 and 16, and reinforcing and spacing portions 17 and 18, respectively, which are at right angles thereto. Thus, the flat portions 15 and 16 are maintained in a spaced relationship by means of abutting portions 17 and 18, and are also reinforced thereby to add rigidity to the overall apparatus. The hinged halves 11 and 12 are free to swing inward and outward, from the position illustrated in FIG. 1, to the position illustrated in FIG. 3.

The open ends 20 of hinged half 11 are provided with portions 21 and 22 which form aligned generally annular portions 24 for receiving a nonrotatable rod 23. The end portions 24 may be bent so as to be adjacent the flat portions 15, and preferably are welded thereto. The nonrotatable rod 23 is for the purpose of allowing the stripper 10 to be conveniently held in the hand when in use as a portable hand instrument as illustrated in FIG. 1, or when picking up the same from a table, storage area or the like when not in use.

The hinged halves 11 and 12 are provided with round rod members 28 and 29, the ends of which extend through openings 30 and 31 in portions 17 and 18, respectively, so as to be securely mounted therein. Rollers 32 and 33 are rotatably mounted on rods 28 and 29, respectively, and easily rotate thereon. As is best seen in FIG. 2, the rods 28 and 29 and the rollers 32 and 33 carried thereby are mounted so as to be spaced apart a distance whereby the portion of the fluid filled tubing 34 which is passing between the peripheral surfaces of rollers 32 and 33 is compressed to a thickness less than normal wall thickness, whereby the fluid is substantially completely stripped from the tubing 34.

As is best seen in FIGS. 2 and 3, a strap-type latch 36 having an opening 37 therein of a size to conveniently receive and securely hold the small protrusion 38 on portion 17 is provided for locking the halves 11 and 12 in the positions illustrated in FIGS. 1 and 2. However, when desired, the latch 36 may be released and the halves 11 and 12 may be swung open to the position shown in FIG. 3. Thus, the latch 36 may be released, the halves 11 and 12 swung to the position shown in

3,604,418

FIG. 3, the end of the tubing 34 near the needle 39 placed between the rollers 32 and 33 at approximately the position shown in FIG. 1, and the halves 11 and 12 then folded together to the position shown in FIGS. 1 and 2 and locked by means of latch 36. The tubing 34, which for purposes of illustration only, is shown in the drawings as being integrally constructed with a prior art blood collecting and dispensing bag 40, is too flexible for the end to be fed initially between the rollers 32 and 33, and also the knot 41 therein would prevent this. The structure described above provides a convenient and readily effective means for overcoming the problems normally associated with positioning the tubing 34 for passage longitudinally between rollers 32 and 33.

The needle 39 is normally detached from the tubing 34 after the knot 41 is tied therein and is discarded. However, for purposes of clarity, the needle 39 as illustrated in the drawings as being retained and with the rubber protective covering 42 in position thereon, so as to show the initial relationship of the knot 41 to the needle 39. It is apparent that the end of tubing 34 is sealed off in an airtight manner by means of knot 41.

The stripper 10 may be unmounted, thereby allowing it to be used as a hand instrument as illustrated in the drawings. However, when desired the stripper 10 may be mounted on any suitable supporting surface by means of screws which are inserted through openings 44 in portions IS, or openings 45 in portions 16. Preferably, when the stripper 10 is mounted, the shorter portion 16 lies flat on the supporting surface and is attached thereto, thereby allowing the rod 23 which is spaced from the supporting surface, to be easily grasped with the hand. Upon release of the latch 36, the hinged half 11 may be swung to the opened position illustrated in FIG. 3 by pulling upward on rod 23 for receiving the tubing 34, and then is returned to the closed position illustrated in FIGS. 1 and 2 by pushing downward on rod 23 and the latch 36 is locked. As is best seen in FIG. 2, the outer end of latch 36 is securely attached by welding to the outer surface of portion 18. The latch 36 extends across portion 17 and beyond a distance sufficient to allow outward pressure to be applied to the outer end, thereby forcing it away from the protrusion 38 and unlocking the same.

When blood is collected from a donor, the rubber covering 42 is removed and the needle 39 is inserted into a vein. The blood flows through the needle, the tubing 34, and into the interior of the blood collecting and dispensing bag 40, which contains a solution 46 of an anticoagulant and/or preservative. The blood which reaches the interior of the bag 40 is mixed with the solution 46 to prevent clotting and to preserve the blood. The bag 40 and the tubing 34 which is integral therewith, the needle 39, and the rubber covering 42 are all of prior art construction and design. Normally, the bag 40 and tubing 34 are formed from a thermoplastic material which is flexible and elastic to some extent. The tubing 34 may be elongated or stretched somewhat upon applying longitudinal tension thereto as it is pulled between the rollers 32 and 33; thus the tubing is stretched as well as compressed as it passes between the rollers 32 and 33. Also, the tubing 34 may be conveniently sealed into lengths providing sufficient blood for a sample for test purposes by application of heat and pressure at predetermined intervals.

After the bag is filled with an amount of blood to constitute a unit (300-500 ml.), the knot 41 is tied near the outer end of the tubing 34 thereby sealing off the end of the tube from the outside atmosphere, and normally the needle 39 is removed and discarded. The tubing 34 is filled with fresh blood at this stage which has not been mixed with the anticoagulant and/or preservative solution 46. In order for the fresh blood in the tubing 34 to be adequately preserved and to prevent it from coagulating or clotting, it must be forced therefrom, mixed with the contents of the bag 40, and then allowed to flow back into the tubing 34. However, the prior art means for stripping the fresh blood from the tubing 34 and replacing it with preserved blood containing the solution 46 was inadequate, as was pointed out previously.

In order to rapidly and efficiently strip the blood from the tubing 34, the hinged halves 11 and 12 are opened to the positions shown in FIG. 3, the outer end of tubing 34 placed between the rollers 32 and 33, the halves 11 and 12 are returned to the position shown in FIGS. 1 and 2, and the latch 36 is locked. Then, the tubing 34 is pulled longitudinally and progressively between the rollers 32 and 33 in the direction shown by the arrows (solid line), thereby compressing the tubing 34 as illustrated in FIG. 2 and elongating the same somewhat due to its elasticity and the longitudinal tension that is applied. This causes the fresh blood to be substantially completely stripped from the tubing, and it flows in the direction of the arrow (dashed line) downward through the tubing 34 and into the bag 40 where it is mixed with the remaining blood and the solution 46 of anticoagulant and/or preservative. When the tubing 34 has been pulled longitudinally through the rollers 32 and 33 until it reaches the point indicated at 47, the latch 36 may be retained in the locked position illustrated in FIGS. 1 and 2, and the contents of bag 40 may be thoroughly agitated and mixed by shaking. At this time, the section of the tubing 34 between knot 41 and point 47 is collapsed, which is due to the vacuum formed therein upon forcing out the fresh blood and the airtight seals formed at the ends by knot 41 and rollers 32 and 33 at point 47. During the mixing operation, the blood is prevented from flowing back into the tubing 34 due to compression of rollers 32 and 33 on the tubing 34 and the airtight seal formed thereby, as best seen in FIG. 2. However, once the latch 36 is released and the halves 11 and 12 are swung to the position illustrated in FIG. 3, the blood in the bag 40 which is now mixed with the solution 46, may be readily forced or sucked back into the collapsed tubing 34 by the vacuum existing therein. The section of the tubing 34 between knot 41 and point 47 then contains blood which will not coagulate and which is adequately preserved. The thermoplastic tubing 34 may be sealed at a plurality of points along its length by application of heat and pressure by prior art practices, to thereby provide sealed samples of blood for the test purposes previously mentioned. INasmuch as substantially all of the blood has been mixed with the anticoagulant and/or preservative, there is no tendency for the samples within tubing 34 to clot or otherwise become unsatisfactory due to the fresh blood not being completely mixed with the solution 46. The tubing 34 may be passed through the stripper 10 in the manner shown in the drawings. However, it also may be passed between the rollers 32 and 33 in the opposite direction, and/or the bag 40 allowed to rest upon the flat surfaces of stripper 10, to thereby provide a rest for the bag while the blood is being stripped from tubing 34. In such instances, it is understood that the stripper 10 may be turned, if desired, so as to allow the blood to flow downward through tubing 34 and into the interior of bag 40 as the tubing 34 is pulled between the rollers 32 and 33.

It is apparent from the above that the surfaces of stripper 10 may be used as a convenient rest for the bag 40, thereby allowing the bag 40 to be grasped and held by the same hand that is holding the stripper 10, and leaving the other hand free to pull the tubing 34 through the rollers 32 and 33. Also, when the tubing 34 has been pulled through the rollers 32 and 33 to the point 47, the latch 36 may be allowed to remain locked while the blood bag 40 and the stripper 10 are shaken, thereby preventing the blood from inadvertently flowing back into the tubing until it has been completely mixed with the contents of the bag. Once the latch 36 is released, the blood flows freely back into the tubing 34 as previously mentioned. When the blood is being passed back into the tubing 34, it is understood that the bag is held at a sufficient elevation to provide a pool of blood in bag 40 at point 47.

The stripper 10 is shown as being used in connection with stripping blood from only one tubing 34. However, it is possible to use the device to strip blood from more than one tubing simultaneously when this is desired.

The blood may be forced from the tubing more than once. For instance, the fresh blood may be forced initially from the

3,604,418 tubing 34 as described above, the mixture of blood and anticoagulant and/or preservative allowed to flow back into the tubing, and this later mixture forced from the tubing as previously described. This will assure that there is no possibility of any blood remaining in the tubing 34 which is not thoroughly mixed with the solution 46. However, as was pointed out previously, normally the blood is substantially completely removed from tubing 34 and is completely mixed with the solution 46 when it is returned to the tubing 34 the first time.

The stripper 10 may be manufactured in a number of sizes to allow ease of handling. Also, the rollers 32 and 33 may be positioned at different distances, so as to allow tubings of various sizes and thicknesses to be stripped effectively.

The detailed description herein is for purposes of illustration only, and it is understood that the invention is not limited to the stripping of blood from the tubing. For example, any type of fluid may be stripped from the tubing 34, including liquids such as water, aqueous solutions or alcohol, and gases such as oxygen, nitrogen or helium. The fluid initially present may be replaced with any other desired type of fluid by the same general procedure that is described herein in connection with the replacement of fresh blood with preserved blood.

An improved embodiment of the stripper of the invention is illustrated in FIGS. 4 through 9 of the drawings. Referring now to FIGS. 4 through 9, the modified stripper 50 includes a top generally U-shaped frame member 51 and a bottom generally U-shaped frame member 52. The bottom U-shaped member 52 has a plate 53 which is welded to the under surface thereof. A generally L-shaped mounting plate 54 is mounted on the under surface of plate 53 by means of threaded bolts 55 which pass through aligned openings 57 and 58 in plate 53 and plate 54 respectively. As is best seen in FIG. 7, the plate 54 has a downwardly depending hook portion 59 which is provided with an internally threaded opening 60 near the end thereof for receiving the externally threaded stem 61 of clamp 65. The stem 61 has an enlarged flattened member 62 on the outer end thereof for ease in hand tightening and a flat inner end 63 which is tightened against supporting surface 64. As is best seen in FIG. 6, the openings 58 are positioned approximately equal distances from the ends of plate 54, and the openings 57 in plate S3 are positioned to match the same. The plate 54 may be positioned as shown in FIGS. 4 through 9 of the drawings for mounting along the right edge of the surface 64, or the plate 54 may be removed and reversed with hook portion 59 running along the left side for mounting on the left edge of a surface. This reversible feature provides for convenient mounting of stripper 50 along either the right or left edges of a mounting surface.

The forward portion of member 51 is provided with an annular protrusion 70, and a spring steel latch strap 71 having an opening 72 for receiving protrusion 70 is mounted on the forward portion of member 52 by means of threaded bolt 73 and nut 74. The bolt 73 is inserted through opening 75 in member 52. The latch 69 thus formed is effective to retain the members 51 and 52 in the positions illustrated in FIG. 6 of the drawings.

The end leg portions of member 52 are provided with upwardly extending members 76 and 77 which form substantially a 90° angle therewith and have openings 78 and 79 therein, respectively. A plate 80 is mounted on the top surface of the end leg portions of member 51 and is welded thereto. The plate 80 extends rearward past the leg ends of member 51 and is shaped so as to pass freely between the members 76 and 77. The plate 80 has spaced openings 81 and 82 formed therein which receive the lower ends of threaded upright members 83 and 84 respectively. The upper ends of threaded members 83 and 84 are welded to a sleeve 85 which is rotatably mounted on bolt 86. The bolt 86 passes from right to left through opening 79 in member 77, sleeve 85, opening 78 in member 76 and opening 89 in stop 88, and is then retained in place by means of nut 87. As is best seen in FIG. 7, the flat portion 90 of stop 88 lies in the path of threaded member 83 when the member 51 is moved to the fully open position illustrated in solid line in

FIG. 4 of the drawings. The member 51 is prevented from moving past the position shown in FIG. 4 by stop 88, thereby retaining the same in a convenient position for pressing downward to the locked position illustrated in FIG. 6 of the drawings.

The plate 80, which carries the member 51, is mounted on the lower ends of left- and right-threaded members 83 and 84 which pass through openings 81 and 82, respectively. The plate 80 is retained in a desired position by means of upper nuts 91 and 92, washers 93 and 94, and lower nuts 95 and 96 on members 83 and 84 respectively. By adjusting the nuts 91, 92, 95 and 96 upward and downward on threaded members 83 and 84, it is possible to adjust plate 80 upward and downward, and/or to position plate 80 horizontally as is illustrated in FIGS. 4 through 8, and/or to position plate 80 at a slight angle such as is illustrated in FIG. 9 of the drawings. This adjustment feature has important advantages as will be discussed more fully hereinafter.

A spring 100 is mounted at its lower end on bolt 101. The bolt 101 passes through opening 103 in upright member 77 and is retained in position thereon by means of nut 102. The spring 100 extends upward over sleeve 85, and thence downward and is retained on threaded member 84 by means of nut 104. The nut 104 may be raised or lowered along member 84 to thereby adjust the tension on spring 100, it is possible to cause the member 51 to raise automatically upon release of the latch 69 to the position illustrated in phantom line in FIG. 4. Upon applying additional upward force to member 51, it is easily raised to the fully opened position illustrated in solid line in FIG. 4 and thereby provide additional working space between the members 51 and 52.

An upper roller 105 is rotatably mounted on pins 106 and 107 which extend through openings 108 and 109 respectively in member 51. Similarly, a lower roller 110 is rotatably mounted on pins 111 and 112 which extend through openings 113 and 114 respectively in member 52. As is best seen in FIGS. 5 and 7, the rollers 105 and 110 are preferably constructed of a steel rod 115 which is covered with a plastic sleeve 116. The rollers 105 and 110 have threaded axially aligned bores 117 at each end which extend partially therethrough for receiving the threaded inner ends of pins 106, 107, 111, and 112 and allowing the rollers 105 and 110 to be conveniently mounted. If desired, washers 118 may be positioned between the ends of steel rods 115 and the inner surfaces of members 51 and 52. The clearance between the rollers 105 and 110 may be varied as desired by adjusting plate 80, which carries member 51, upward or downward as previously described. This adjustable feature allows tubing of varying thickness to be stripped effectively.

A pair of adjustable guide members 119 and 120 are mounted on the plate 53 by means of spaced bolts 121 and 122 which extend through openings 123 and 124 and are retained therein by nuts 125 and 126, respectively. As is best seen in FIG. 9, the guide members 119 and 120 may be centrally positioned as is shown in solid line, or positioned to the left or right thereof as is shown in phantom line. This may be accomplished by loosening nuts 125 and 126, arranging the guide members 119 and 120 as desired, and then retightening nuts 125 and 126.

As is best seen in FIG. 9, the axis of rollers 105 and 110 may be positioned at an angle to each other by adjusting nuts 91, 92, 95 and 96 so as to retain plate 80 at an angle, thereby changing the angle of the axis of upper roller 105 with respect to the axis of lower roller 110. This results in a variable clearance between the rollers 105 and 110 and it is possible to obtain an intermediate clearance such as is illustrated in solid line between the guide members 119 and 120, or a more restricted clearance or a wider clearance, such as is illustrated to either side thereof in phantom line. It is possible to strip fluid from a variety of tubings which have different wall thicknesses and diameters simply by adjusting the guide members 119 and 120 to the position where the rollers 105 and 110 have exactly the right clearance. This feature of the invention

3,604,418 is of importance as often it is desired to strip fluid from several tubings having different thicknesses and this cannot be accomplished without readjusting the spacings between the rollers IOS and 110 when using prior art apparatus.

The stripper SO is especially easy to use. Preferably stripper 50 is clamped to the side edge of a table or the like by means of clamp 61, the top member SI is raised to the position illustrated in solid line in FIG. 4, and then the tubing 127 for blood collection bag 128 is positioned on top of roller 110 and between the guide members 119 and 120, as is best seen in FIGS. S and 7. The top member 51 is pushed downward onto the bottom member 52, thereby causing protrusion 70 to slip into opening 72 in strap 71 and locking the top and bottom members 51 and 52 by means of latch 69 in the position illustrated in FIGS. 6 through 9 of the drawings. When the stripper 50 is locked by latch 69, the rollers 105 and 110 compress the tubing 127 to less than its normal wall thickness such as is illustrated in FIG. 6 of the drawings. The tubing 126 may be pulled between the rollers 105 and 110 in the direction of the arrow to thereby strip fluid therefrom and cause it to flow into the bag 128. The outer end of tubing 127 is preferably rendered airtight such as by tying a knot therein as previously described, and during the stripping step a vacuum is formed in the tubing 127 between the knot and the rollers 105 and 110. When the tubing 127 is pulled between the rollers 105 and 110 until the bag 128 is reached, the fluid formerly within tubing 127 is now within the bag 128 and it is mixed with the solution therein as previously described. While holding the bag 128 at a sufficiently high level to ensure that a pool of liquid is formed at the end of tubing 127 where it joins the bag 128, the latch 69 is released thereby allowing the top member 51 to rise to the position illustrated in fig. 4. This releases the tubing 127 from between rollers 105 and 110 and allows the fluid in bag 128 to rush back into tubing 127. The stripping step may be repeated several times so as to assure that all of the original fluid has been removed from tubing 127 and is mixed with the solution in bag 128. As was pointed out previously, any type of fluid, whether gaseous or liquid, may be stripped from plastic tubing with stripper 50.

It is apparent from the foregoing description that the action of spring 100 makes usage of the stripper 50 much easier and more convenient. Also, as the stripper 50 opens from the top rather than from the side as described in the earlier embodiment illustrated in FIGS. 1 through 3 of the drawings, this assures easier threading of tubing 127 and usage. ADditionally, the adjustable feature for the rollers 105 and 110 allows the tension on the rollers to be adjusted, and also allows the angle between the rollers to be adjusted, so that tubings of different thicknesses and diameters may be stripped. Further, the guide members 119 and 120 may be adjusted so as to keep the plastic tubing in a desired general area of the surfaces of the rollers 105 and 110.

The stripper 50 is economical to construct and yet it is very substantial and strong. The various parts of the stripper 50 may be made from any suitable materials that are economical and of sufficient strength. Usually, it is preferred that the sleeves 116 be made of plastic and that the remaining parts be made of steel or other suitable metals.

The foregoing detailed description and the drawings are for purposes of illustration only, and are not intended as being limiting to the spirit or scope of the appended claims.