Abstract:
A peristaltic pumping apparatus for use in blood processing procedures, comprising: a pump rotor rotatable about a rotational axis and a pump raceway circumferentially spaced about the axis; a pump cap disposed atop the pump rotor, the pump cap having a finger configured to engage a tubing loop of a length of tubing at a time of loading the tubing and guide the tubing loop within the raceway along the length of the tubing loop; and wherein the pump cap further comprises a tensioning wall disposed laterally opposite the finger, the tensioning wail configured to engage a length of the tubing loop at a time of unloading the tubing and provide tension to the tubing length as the tubing loop exits the raceway.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application ciaims the benefit of U.S. Non-Provisional patent application Ser. No. 14/554,289 filed Nov. 26, 2014, which is expressly incorporated herein by reference in its entirety. 
     
    
     FIELD OF THE DISCLOSURE 
       [0002]    The present disclosure is directed to systems and methods for pumping fluid within flexible tubing. More particularly, the present disclosure is directed to systems and methods for peristaltic pumping of fluids used in connection with medical devices. 
       BACKGROUND 
       [0003]    Roller or peristaltic pumps have many uses in the medical field. For example, roller pumps may be used in medical devices, such as automated apheresis and blood processing devices, to push fluid (e.g., blood or blood components) through flexible tubing. The operation of a roller pump is to pump fluid by positive displacement using revolving rollers that occlude the flexible tubing. Generally, roller pumps may be simply structured, generate a consistent flow, and use disposable tubing through which a fluid medium is transferred. 
         [0004]    Roller pumps generally comprise a pump drive and a pump head. The pump drive causes rotation of the pump head to pump a fluid medium. The pump head often comprises a pump stator and a pump rotor. The pump stator may be a chamber or housing having an inner circumferential surface (or “raceway”) against which one or more tubes are compressed by the pump rotor. The pump rotor, which may be rotatable relative to the stator and raceway, may be arranged in the pump stator in such a manner that the pump rotor engages tubing loops positioned in the pump stator with one or more rollers. Upon rotation of the pump rotor by a rotating shaft that is otherwise part of the pump drive, the roller(s) may compress the tubing loop against the inner circumferential surface of the pump stator as it is rolled along the tubing. The fluid medium contained in the tubing may then be transported in a direction of the pump rotor rotation. 
       SUMMARY 
       [0005]    There are several aspects of the present subject matter which may be embodied separately or together in the devices and systems described and claimed below. These aspects may be employed alone or in combination with other aspects of the subject matter described herein, and the description of these aspects together is not intended to preclude the use of these aspects separately or the claiming of such aspects separately or in different combinations as set forth in the claims appended hereto. 
         [0006]    According to an exemplary embodiment, the present disclosure is directed to a peristaltic pumping apparatus for use in blood processing procedures, comprising a pump rotor rotatable about a rotational axis and a pump raceway circumferentialiy spaced about the axis; a pump cap disposed atop the pump rotor, the pump cap having a finger configured to engage a tubing loop of a length of tubing at a time of loading the tubing and guide the tubing loop within the raceway along the length of the tubing loop; and wherein the pump cap further comprises a tensioning wall disposed laterally opposite the finger, the tensioning wail configured to engage a length of the tubing loop at a time of unloading the tubing and provide tension to the tubing length as the tubing loop exits the raceway. 
         [0007]    According to an exemplary embodiment, the present disclosure is directed to a method for loading and unloading a pump tubing loop into and out of a pump raceway, the method comprising: placing in the vicinity of a pump raceway a flexible tubing loop of a length of tubing; engaging the tubing loop with a finger of a pump cap positioned atop a pump rotor and guiding the tubing loop within the raceway along a iength of the tubing loop with the finger, wherein the pump rotor is rotatable about a rotational axis and the pump raceway is circumferentially spaced about the axis; and unloading from the pump raceway the flexible tubing loop, wherein a tensioning wall disposed laterally opposite the finger engages a length of the tubing loop and provides tension to the tubing length as the tubing loop exits the raceway. 
         [0008]    According to an exemplary embodiment, the present disclosure is directed to a peristaltic pumping apparatus for use in a medical device, comprising a pump rotor rotatable about a rotational axis and a pump raceway circumferentiaiiy spaced about the axis. The apparatus also comprises a pump cap disposed atop the pump rotor, the pump cap having a finger configured to engage a tubing loop of a length of tubing at a time of loading the tubing and guide the tubing loop within the raceway along the length of the tubing loop. The pump cap further comprises a tensioning wall disposed laterally opposite the finger, the tensioning wall configured to engage a length of the tubing loop at a time of unloading the tubing and provide tension to the tubing length as the tubing loop exits the raceway. The finger extends radially outward from the rotational axis of the pump rotor beyond a circumference of the pump rotor and the tensioning wall has a contour that generally follows the circumference of the pump rotor. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    Features, aspects, and advantages of the present embodiments will become apparent from the following description, appended claims, and the accompanying exemplary embodiments shown in the drawings, which are briefly described below. 
           [0010]      FIG. 1  is a perspective view of a fluid processing system incorporating a peristaltic pumping apparatus, according to an exemplary embodiment; 
           [0011]      FIG. 2  is a diagrammatic view of a disposable fluid circuit and cassette that may be used in combination with the fluid processing system of  FIG. 1 , according to an exemplary embodiment; 
           [0012]      FIG. 3  is a perspective view of a pump cap known in the art, according to an exemplary embodiment; 
           [0013]      FIG. 3A  is a perspective view of a pump apparatus, according to an exemplary embodiment; 
           [0014]      FIG. 3B  is a perspective view of a pump rotor assembly and pump cap, according to an exemplary embodiment; 
           [0015]      FIGS. 4A-4C  are perspective views of a cassette and associated tubing loop at various points of loading, according to an exemplary embodiment; and 
           [0016]      FIGS. 5A-5C  are perspective views of a cassette and associated tubing loop at various points of unloading, according to an exemplary embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    Some embodiments may minimize tangling, bunching, and/or folding of pump tubing loops during the loading or unloading of the tubing loops into and out of the raceway. 
         [0018]    Some embodiments may enable automatic loading of pump tubing loops into the pump raceway prior to a medical procedure and automatically unload pump tubing loops out of the pump raceway upon completion of the procedure. 
         [0019]    Some embodiments may minimize loading and unloading issues with both shorter and longer tubing loops. 
         [0020]    Some embodiments may minimize loading and unloading issues with both faster and slower pump rotational speeds. 
         [0021]    Some embodiments may minimize loading and unloading issues with both faster and slower speeds with which a cassette is loaded and unloaded. 
         [0022]      FIG. 1  shows an exemplary fluid processing system  10  incorporating a peristaltic pumping apparatus  92  used in conjunction with a disposable fluid circuit  12  ( FIG. 2 ). The fluid processing system  10  may have one or more features of an apheresis device, such as a system marketed as the AMICUS® separator by Fenwal, Inc. of Lake Zurich, Ill., as described in greater detail in U.S. Pat. No. 5,868,696, which is hereby incorporated herein by reference in its entirety, although any suitable apheresis device or blood processing system may be used. The system  10  can be used for processing various fluids, including, but not limited to whole blood, blood components, or other suspensions of biological cellular materials. While an improved pumping apparatus  92  will be described herein with reference to exemplary system  10  and disposable fluid circuit  12 , it should be understood that these principles may be employed with other fluid processing systems and disposable fluid circuits without departing from the scope of the present disclosure. 
         [0023]    Fluid entering the disposable fluid circuit  12  may be pumped thereinto by one or more pumps  92  of the fluid processing system  10  acting upon one or more of the flexible tubing loops  50  extending from the cassettes  16 ,  16   a , and  16   b  of the flow circuit  12 . The tubing loop  50  may be in an erect and outwardly bowed position from cassette  16 ,  16   a , and  16   b . An exemplary cassette  16 , exemplary pump mechanism, and associated cassette holders  94  are described in greater detail in U.S. Pat. No. 5,480,294, which is hereby incorporated herein by reference in its entirety, although any suitable cassette, pump mechanism, and cassette holder may be used. The pump mechanism may optionally be equipped with a pump cap, such as pump cap  100   a  that is known in the art, depicted in  FIG. 3 . The contour of known pump cap  100   a  generally conforms to the circumference of the underlying rotor of the pump mechanism and may play a role in protecting the rotor and pump mechanism. 
         [0024]    Turning to the cassette holders  94  in  FIG. 1 , each may receive and grip one of the cassettes  16 ,  16   a , and  16   b  along the two opposed sides edges  130  in the desired operating position. The cassette holder  94  may include a pair of peristaltic pump apparatuses  92 . When the cassette  16  is gripped by the cassette holder  94 , tubing loops  50  extending from the cassette  16  as shown in  FIG. 2  may make operative engagement with the pump apparatuses  92 . The pump apparatuses  92  may be operated to cause fluid flow through the cassette  16 . Although the embodiment in  FIG. 1  depicts three cassette holders  94  configured to engage tubing loops  50  of the fluid circuit  12 , any number of cassette holders  94  may be incorporated into the fluid processing system  10 . Although  FIG. 1  also depicts peristaltic pump apparatuses  92  disposed on laterally opposing sides of cassette holders  94 , the pump apparatuses  92  may be oriented in a variety of configurations depending on the orientation and number of the tubing loops  50  extending from cassettes  16 ,  16   a , and  16   b.    
         [0025]    Turning to  FIGS. 3A and 3B , detailed views of the pump apparatus  92  are shown. The pump apparatus  92  may comprise a pump rotor assembly  292  rotatable about a rotational axis A. An outer wall  294  may extend at least partially around the back side of each rotor assembly  292 . The space between the outer wall  294  and the rotor assembly  292  forms a pump raceway  296  circumferentialiy spaced about the axis A. When a cassette  16 ,  16   a , and  16   b  is gripped by the side edges  130 , the tubing loops  50  may extend into the pump raceway  296 . Loading a cassette  16  and tubing loop  50  may be performed by the side edges  130  moving the tubing loop  50  and cassette  16  toward the pump rotor in a direction generally parallel to the rotational axis A of the pump rotor. Unloading a cassette  16  and tubing loop  50  may be performed by the side edges  130  moving the tubing loop  50  and cassette  16  away from the pump rotor in a direction generally parallel to the rotational axis A. Each rotor assembly  292  may include a set of diametrically spaced rollers  300 , although the spacing of one or more rollers  300  may be varied. In use, as the pump rotor  292  rotates, the rollers  300  in succession may compress the associated tubing loop  50  against the outer wall  294  of the pump raceway  296 . This peristaltic pumping action may urge fluid through the associated loop  50 . 
         [0026]    Each rotor assembly  292  may have a pump cap  100  capping the assembly  292 . The pump cap  100  may comprise a tensioning finger  302 , which may extend radially outwards from the rotational axis A of the pump rotor assembly  292  and beyond the circumference of the rotor assembly  292 . The tensioning finger  302  may be disposed above the height of the rotor assembly  292  and the raceway  296  and may facilitate the smooth loading of the tubing loop  50  into the raceway  296  by catching and guiding the tubing loop  50  in place into the raceway  296 . The tensioning finger  302  may assure that the tubing loops  50  are properly oriented and aligned within their respective pump races  296  so that the desired peristaltic pumping action occurs. 
         [0027]    The pump cap  100  of the rotor assembly  292  may also comprise a tensioning wall  303  disposed laterally opposite the tensioning finger  302  and also above the height of the rotor assembly  292  and the raceway  296 . The contour of the tensioning wall  303  may generally follow the circumference of the rotor assembly  292 . The tensioning wall  303  may facilitate the smooth unloading of the tubing loop  50  out of the raceway  296  by preventing slack in the tubing loop  50  during unloading and providing tension to the tubing loop  50  as it exits the raceway  296 . Providing tension to the tubing loop  50  may minimize the tubing loop  50  from bending and folding over itself during the unload process. 
         [0028]      FIG. 4A  depicts a cassette  16  and associated tubing loop  50  just prior to being loaded into the raceway  296 . The tubing loop  50  is disposed in the vicinity of the raceway  296  at the height of the pump cap  100  above the raceway  296  and generally above the rotor assembly  292 . The pump rotor  292  may begin rotating about its rotational axis A prior to the tubing loop  50  having settled within the raceway  296 . 
         [0029]    Turning to  FIG. 4B , as the side edges  130  of the cassette holders  94  load the cassette  16  into the cassette holders  94 , the tubing loop  50  may begin loading into the raceway  296  around the rotor assembly  292 , starting with the portions of the tubing loop  50  closest to the cassette  16 . The portion of the tubing loop  50  distal from the cassette  16  may still be unloaded and may straddle a portion of the pump cap  100 . 
         [0030]    Referring to  FIG. 4C , the rotation of the pump rotor  292  about its rotational axis A allows the finger  302  to catch the tubing loop  50  such that a portion of the loop  50  proximal to the cassette  16  is caught underneath the finger  302 . The finger  302  may guide the tubing loop  50  along its length into the raceway  296 . The finger  302  may take one or more rotations of the pump rotor  292  to guide the tubing loop  50  completely into the raceway  296 . It may take more rotations of the finger  302  to guide the tubing loop  50  completely info the raceway  296  in cases where the tubing loop  50  is shorter. Once the tubing loop  50  has been fully loaded into the raceway  296 , the rollers  300  of the rotating pump rotor  292  may facilitate transport of fluid along the tubing loop  50 . 
         [0031]      FIG. 5A  shows an embodiment in which the cassette  16  is loaded into the cassette holders  94  and has just commenced the unloading process. As the side edges  130  elevate the cassette  16  into an unloading position, portions of the tubing loop  50  most proximal to the cassette  16  may first exit the raceway  296 . The pump rotor  292  and hence the pump cap  100  may continue to rotate during the unloading process. 
         [0032]    Referring to  FIG. 5B , as portions of the tubing loop  50  more distal to the cassette  16  continue to exit the raceway  296 , the tensioning wail  303  may progressively make more contact with the tubing loop  50 . The tensioning wall  303  may create tension along the length of tubing loop  50  so as to avoid slack and therefore minimize portions of the tubing  50  bending and folding over itself as well as to expedite the exit of all portions of the tubing loop  50  from the raceway  296 .  FIG. 5C  shows a point at which the entire tubing loop  50  has exited the raceway  296 . The tensioning wail  303  may hold a length of the tubing loop  50  taut so that loop  50  does not fall back into the raceway  296 . The tensioning wall  303  may therefore allow the fluid processing system  10  and pumping apparatus  92  to accommodate tubing loops of shorter and longer lengths. 
         [0033]    The embodiments disclosed herein are for the purpose of providing a description of the present subject matter, and it is understood that the subject matter may be embodied in various other forms and combinations not shown in detail. Therefore, specific embodiments and features disclosed herein are not to be interpreted as limiting the subject matter as defined in the accompanying claims.