Abstract:
A flow control valve includes a stem extending into an interior bore defined by a wall of a flow control member of the valve, the stem and the wall defining therebetween a cylindrical space allowing fluid communication between apertures formed in differing planes of the flow control member.

Description:
PRIORITY CLAIM 
       [0001]    This application is a continuation application and claims priority to and the benefit of U.S. patent application Ser. No. 11/458,903, entitled Multirate Tubing Flow Restrictor, filed Jul. 20, 2006. 
     
    
     BACKGROUND 
       [0002]    The present invention generally relates to a flow control valve for medical liquid, and more particularly to a multi-rate flow control device for dispensing a medical fluid at a selected one of a plurality of discrete flow rates. 
         [0003]    In the delivery of medical liquids, such as medication, drugs, chemotherapeutic agents, intravenous solutions or the like, it is known to use a flow control valve that permits the user to select a particular flow rate from a range of discrete flow rates. One such flow control valve, which uses glass capillary structures to control the flow rate, is described in U.S. Pat. No. 6,273,133 entitled “Fluid Flow Rate Switching Device.” The device shown there has two internal passageways, each with a glass capillary structure that limits flow through the passageway. A valve member directs fluid flow through either or both of the passageways to provide several different flow rates through the flow control device. While this device works satisfactorily, the use of glass capillary structures can add to the cost and there is a desire to have flow control devices with a greater selection of available flow rates. Although this is but one example, there continues to be a need for medical fluid flow control valves that address one or more of the drawbacks found in prior valves. 
       SUMMARY 
       [0004]    The present invention is embodied in a novel flow control device or valve that is relatively easily and inexpensively manufactured and provides a variety of flow rates for doctor or user selection. In one aspect of the present invention, a flow control valve for dispensing medical liquid is provided. The flow control valve includes a housing comprising an inlet, an outlet, and a flow path therebetween. A plurality of flow restrictors in the flow path define a plurality of flow streams of differing flow rates. A flow control member is disposed in the flow path and has at least one aperture disposed in a first plane and at least one aperture disposed in a second plane which is spaced apart from the first plane. The flow control member is movable relative to the housing between a first position and at least one second position. In the first position, one of the at least one apertures in the first plane is in communication with at least one of the flow streams to define a first flow rate through the valve. In the second position, one of the at least one apertures in the second plane is in communication with a different one of the flow streams to define a second flow rate through the valve different from the first flow rate. 
         [0005]    In a second aspect of the present invention, a flow control valve for dispensing medical liquid is also provided. The flow control valve includes a housing comprising an inlet, an outlet, and a flow path therebetween. A plurality of flow regulators disposed in the flow path define a plurality of differing flow rates. A first of the plurality of flow regulators is defined by a tube of a first selected size. A second of the plurality of flow regulators is defined by a tube of a second selected size which is different from the size of the first flow regulator. A flow control member disposed in the flow path has at least one discrete aperture at each of a first and second spaced apart locations. The flow control member is movable relative to the housing between a first position and a second position and defines an annular gap which is in communication with the outlet. In the first position, one aperture in the first location is in communication with one of the flow regulators to define a first flow rate through the valve. In the second position, one aperture in the second location is in communication with a different one of the flow regulators to define a second flow rate through the valve which is different from the first flow rate. 
         [0006]    The flow control member of the valve in this aspect of the invention is rotatable between at least a first and second position. In the first position, one of the plurality of apertures in the first plane is in communication with the first opening in the annual wall to define a first flow rate through the valve. In the second position, one of the plurality of apertures in the second plane is in communication with the second opening in the annual wall to define a second flow rate through the valve that is different from the first flow rate. 
         [0007]    In a fourth aspect of the invention, a flow control valve for dispensing medical liquid is provided. The flow control valve includes a housing comprising an inlet, an outlet, and a flow path therebetween. The housing includes an annular wall defining an interior bore and first and second axially spaced-apart openings extending through the annular wall. Within the interior bore, a flow control member is rotatably disposed and has a plurality of discrete apertures in each of a first and second plane. 
         [0008]    The flow control member in this fourth aspect of the invention also defines a portion of a passageway that extends in a direction generally normal to at least one of the first and second planes and communicates with the discrete apertures and one of the inlet and outlet regardless of the position of the flow control member. 
         [0009]    Additional features and advantages are described herein, and will be apparent from the following Detailed Description and the figures. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0010]      FIG. 1  is a perspective view of one embodiment of a flow control device employing the present invention; 
           [0011]      FIG. 2  an exploded perspective view of the view of the flow control device of  FIG. 1 . 
           [0012]      FIG. 3  is an end view of the flow control device of  FIG. 1 . 
           [0013]      FIG. 4  is a cross-sectional view of the flow control device of  FIG. 1  taken through line  4 - 4  of  FIG. 3 . 
           [0014]      FIG. 4A  is a broken away, perspective of a portion of  FIG. 1 , showing the inlet diverging into three separate flow restrictors or tubes. 
           [0015]      FIG. 5  is a cross-sectional end view of the flow control device of  FIG. 4  taken through line  5 - 5 . 
           [0016]      FIG. 6  is a top view of the base of the flow control device of  FIG. 2 . 
           [0017]      FIG. 7  is a side view of the base of the flow control device illustrated in  FIG. 6 . 
           [0018]      FIG. 8  is a cross-sectional view of the base of the flow control device of  FIG. 6 , taken through line  8 - 8 . 
           [0019]      FIG. 9  is a cross-sectional, end view of the base of the flow control device of  FIG. 6 , taken through line  9 - 9 . 
           [0020]      FIG. 10  is a side view of the flow control member of  FIG. 1 . 
           [0021]      FIG. 11  is a top view of the flow control member of  FIG. 10 . 
           [0022]      FIG. 12  is a bottom, plan view of the flow control member of  FIG. 10 . 
           [0023]      FIG. 13  is a cross-sectional view of the flow control member of  FIG. 11  taken along line  13 - 13 . 
           [0024]      FIG. 14  is a cross-sectional view of the flow control member of  FIG. 13  taken along line  14 - 14 . 
           [0025]      FIG. 15  is a cross-sectional view of the flow control member of  FIG. 13  taken along line  15 - 15 . 
           [0026]      FIG. 16  is a cross-sectional view of the flow control member of  FIG. 13  taken along line  16 - 16 . 
           [0027]      FIG. 17  is a cross-sectional view of the flow control member of  FIG. 13  taken along line  17 - 17 . 
           [0028]      FIG. 18  is a top view of portion of the housing of the flow control device of  FIG. 1 . 
           [0029]      FIG. 19  is an interior view of the inlet end of the flow control device of  FIG. 8 , taken along line  19 - 19 , with the tubes removed. 
           [0030]      FIG. 20  is a cross-sectional view of  FIG. 19  taken through line  20 - 20 . 
           [0031]      FIG. 21  is a top view of a tool used to adjust the intended position of the flow control member of the flow control device of  FIG. 1 . 
           [0032]      FIG. 22  is a side, cross-sectional view of the tool of  FIG. 21  taken along line  22 - 22 . 
           [0033]      FIG. 23  is a cross-sectional, end view of the tool of  FIG. 22  taken along line  23 - 23 . 
           [0034]      FIG. 24A  is a diagram which pictorially illustrates an expanded view of a generally cylindrical side wall of the flow control member identifying the component flow streams that are in communication with the outlet at different positions of the flow control member in the flow control device of  FIG. 1 . 
           [0035]      FIG. 24B  is a top view of the flow control member with superimposed indicator lines showing each of the different rotational positions which the flow control member in the flow control device of  FIG. 1 , corresponding to the arrangement of the apertures for the flow streams shown in  FIG. 24A . 
       
    
    
     DETAILED DESCRIPTION 
       [0036]    Referring to  FIG. 1 , the present invention is generally embodied in a flow control device, generally at  30 . The flow control device  30  includes a housing  32  having an inlet  34  and an outlet  36 , and a flow path defined between the inlet and outlet. The embodiment shown in the drawings is for purpose of illustration only, and it should be understood that the form and features of the flow control device of the present invention may vary according to the desired application or intended function. The scope of this invention is as defined in the claims now or hereafter submitted and except to the extent included in such claims, is not limited to any specific form, feature or function described herein. 
         [0037]    As shown in  FIG. 2 , in exploded view, the illustrated flow control device  30  includes a base or bottom portion  38 , a top and side portion  40  and an end portion  42 . The housing is preferably made of rigid molded plastic, although other suitable materials may also be used. 
         [0038]    The flow control device of the present invention preferably includes a movable flow control member associated with the housing to control flow therethrough. In the illustrated embodiment, the base  38  has an upstanding, generally cylindrical or annular wall  44 , which forms a generally cylindrical interior bore  46  for receiving a rotating flow control member or valve element  48  that serves, in part, to control the flow rate of fluid through the housing. As best seen in  FIGS. 2 ,  4  and  5 , a plurality of axially spaced-apart apertures or ports  50   a ,  50   b  and  50   c  extend through the annular wall  44 . Outlet  36  also includes an aperture or port  52  extending through wall  44 . 
         [0039]    A length of plastic tubing  54   a ,  54   b ,  54   c  of selected size extends between each aperture  50   a ,  50   b  and  50   c  and the inlet  34 . Each tube is of a different size, diameter and/or length, to act as a flow restrictor or a flow setter to create a fluid flow stream having a selected flow rate different than the flow rate in the other tubes. For example, under the normal pressure exhibited by an elastomeric pump in the flow administration of IV solution to a patient, tube  54   a  is sized to provide a flow stream with a flow rate of 1.0 ml/hr between the inlet port and aperture  50   a , tube  54   b  is sized to provide a flow stream with a flow rate of 2.0 ml/hr between the inlet port and aperture  50   b , and tube  54   c  is sized to provide a flow stream with a flow rate of 4.0 ml/hr between the inlet port and aperture  50   c . In a preferred embodiment the 1.0 ml/hr tubing has an ID of 0.0021 inches and a length of 3.67 inches, the 2.0 ml/hr tubing has an ID of 0.0031 inches and a length of 3.65 inches and the 4.0 ml/hr tubing has an ID of 0.0036 inches and a length of 3.20 inches. It should be understood that tubings having different ID&#39;s and lengths may be employed to get the illustrated flow rates or other desired flow rates. It is apparent that use of a tubing having a smaller diameter and/or longer length would yield a tubing which provides a flow stream of 0.5 ml/hr. 
         [0040]    Although illustrated with three different tubes, additional or fewer tubes may also be used. Also, structures other than tubing may be employed to function as flow restrictors or flow setters, including orifices, molded passageways, and the like. Tubing, however, is relatively easy to extrude and bond to the respective ports or apertures, and thus serves to minimize manufacturing cost. 
         [0041]    In accordance with the present invention, a plurality of selected discrete flow rates may be provided through the flow control device by selectively allowing flow from one or more of the flow restrictor tubings to pass through the housing. In the illustrated device, this flow control is provided by the flow control or valve member  48 , which is best seen in  FIGS. 10-17 , in cooperation with the features described above. 
         [0042]    As shown in  FIGS. 10 and 13 , the flow control member is generally hollow and cylindrical, and made of molded plastic or other suitable material. The flow control member has an exterior surface of generally uniform diameter except for an enlarged annular collar  56  at one end and an annular groove or channel  58  at the other end. “Uniform diameter” is intended to include a surface having a slight taper, such as a molding draft angle or taper, on either or both of the control member  48  and inner surface of bore  46 . The illustrated flow control member has one or more apertures in each of a plurality of axially spaced apart regions or planes. In the illustrated valve member, there are four such regions or planes, generally shown in  FIGS. 14-17 , although the number can vary. At least one of the planes, however, includes a plurality of apertures. 
         [0043]    More specifically.  FIG. 14  is a cross-sectional view taken along line  14 - 14  of  FIG. 13 , which is generally perpendicular to the axis  60  of the flow control member  48 . For purposes of this description this will be referred to as region or plane  14 - 14 . As evident from  FIGS. 13 and 14 , plane  14 - 14  extends through the annular groove  58 , and has a single aperture  62 . As will be described in more detail later, when assembled in the housing, annular groove  58  is in registration (fluid communication) with outlet port aperture  52  regardless of the orientation of the flow control member  48 . 
         [0044]    Using the same terminology, plane  15 - 15  is located at the other end of the flow control member  48 . As seen in  FIG. 15 , this region or plane contains four apertures  64 , circumferentially spaced apart 90°, and are oriented (in a clockwise direction from the 9 o&#39;clock position) at the 45°, 135°, 225° and 315° positions. As best seen in  FIG. 16 , plane or region  16 - 16  of  FIG. 13  also includes four apertures  66 , which are oriented (in a clockwise direction from the 9 o&#39;clock position), at the 45°, 90°, 225° and 270° positions. Plane  17 - 17  of  FIG. 13  is located between planes  14 - 14  and  16 - 16 . As shown in  FIG. 17 , this plane or region includes four apertures  68 , which are oriented (in a clockwise direction from the 9 o&#39;clock position) at the 0°, 225°, 270° and 315° positions. 
         [0045]    As noted earlier, and as best seen in  FIG. 4 , the flow control member  48  is rotatably received within the bore  46  defined in the base portion  38  of the housing  32 . The flow control member  48  is sized so that it is in relatively liquid tight interference fit with the inner surface of bore  46 . More specifically, the fit between the outside surface of the flow control member  48  and inner surface of bore  46  should preferably be sufficiently liquid tight so that there is no substantial fluid flow or leakage between the surfaces, either between apertures  50   a - 50   c  or between apertures  50   a - 50   c  and the outlet aperture  62 . The fit however cannot be so light that the flow control member  48  may not be rotated with the typical force which may be applied to the member. Thus a leakage tight fit is provided without the use of O-rings or other typical rotational seals which would increase the complexity of manufacture and cost. 
         [0046]    When fully inserted into the bore, the annular groove  58  of the flow control member is aligned with outlet port aperture  52 , and planes  15 - 15 ,  16 - 16  and  17 - 17  are each aligned, respectively, with one of the apertures  50   a ,  50   b  and  50   c  through the cylindrical wall  44 . By rotating flow control member, one or more of the apertures  64 ,  66  and  68  in each plane or region can be brought into registration or alignment (flow communication) with any of the respective apertures  50   a ,  50   b ,  50   c , through which the flow stream passes from one of the flow restrictor tubings  54   a ,  54   b  and  54   c.    
         [0047]    To stabilize the flow control member and aid assembly, the housing base  38  includes a center cylindrical support member  70  within bore  46 . When assembled, the support member extends through the center of the flow control member  48 . The upper end of the support member  70  is tapered at  72  to engage a matching internal taper  74  in the flow control member to assist in assembly and centering alignment. 
         [0048]    The outside diameter of the support member  70  is smaller than the inside diameter of flow control member  48  and, as a result, an annular flow path  76  in the form of an annular region or gap is defined between them. In the illustrated orientation, this flow path  76  extends axially or vertically between the support member  70  and flow control member  48  through each of the horizontal regions or planes  14 - 14  through  17 - 17 . Thus, fluid flowing through any of the apertures in planes  15 - 15  through  17 - 17  is combined in and conducted through the flow path  76  defined between support member and flow control member and directed to aperture  62  (in plane  14 - 14 ). 
         [0049]    The outer diameter of the support member  70  and inside diameter of the control member  48  are preferably sized to provide several desired benefits. One such benefit is to define a flow path which does not provide an appreciable resistance to flow but also define a volume which is low to minimize priming and residual volume. Because of the typical low flow rates, the larger the volume the longer the time to prime, and the larger the volume of fluid that is not dispensed to the patient. A second benefit is that the thickness of the tubular walls of the control member  48  may be controlled such that it may be molded with tight tolerances to provide the fluid tight interference fit with the bore  46  as described above. It has been found that if the thickness is too great, it is harder to maintain the tolerance of the outer diameter of the control member  48  to provide the desired interference fit. 
         [0050]    Another benefit of the flow control member  48  is the placement of an aperture  62  that communicates in all rotational positions, via annular groove  58 , with outlet port aperture  52 . Thus in a preferred embodiment regardless of the orientation of the flow control member  48  to provide a desired communication with none, one or more of the apertures  50 , the outlet port aperture  52  is always in communication with the annular flow path  76 . 
         [0051]    As best seen in  FIGS. 2 and 4 , when assembled, the upper annular collar  56  of the flow control member is captured between an internal shoulder  78  of bore  46  and the top wail of the housing. To rotate the flow control member to selected flow positions, the upper end of the flow control member is accessible through an opening  80  in the upper wall of the housing (see  FIG. 2 ). The upper end of the flow control member defines a recess  82  of selected shape, such as square, triangular or other cross-sectional to interfit with a complementary—shaped end  84  of tool  86  to allow the clinician or health care worker to rotate the flow control member. Preferably the recess  82  is located recessed or below the upper wall of the housing to prevent inadvertent or unauthorized turning of the flow control member by one who does not possess the tool  86 . 
         [0052]    Referring in particular to  FIGS. 4 and 10 , the flow device  30  ( FIG. 1 ) includes means for imparting a tactile sensation to the setting of the desired flow rate. In particular the upper annular collar  56  includes a series of detents  57  radially spaced about the upper surface of the collar. These detents  57  register with a downwardly projecting bump  59  on the top portion  40  to preferably impart a tactile and audible indication that the flow control member  48  is properly oriented to provide the desired flow rate. The flow rates may also be depicted on the top portion  40  as is illustrated in  FIG. 2 . 
         [0053]    By way or example when the flow rates provided by the flow restrictor tubing  54   a  is 0.5 ml/hr: by flow restrictor tubing  54   b  is 1.0 ml/hr and by flow restrictor tubing  54   c  is 2.0 ml/hr and as depicted in  FIGS. 24A and 24B , the illustrated flow control device provides seven specific discrete flow rates, in addition to an “off” position.  FIG. 24B  shows eight different rotational positions of the flow control member, each designated by a letter A-H. The graph or chart in  FIG. 24A  diagrammatically shows which apertures in the flow control member are in communication with which of the flow restrictor tubing in each of the rotational positions. With these example provided restrictor  110 W tubing, in position A, one of the apertures  64  in plane  15 - 15  communicates with aperture  50   a  and the flow restrictor tubing  54   a , thereby providing a flow rate of 0.5 ml/hr. No aperture in planes  16 - 16  or  17 - 17  communicates with the other flow restrictor tubing. The resultant flow rate through the valve is therefore 0.5 ml/hr. 
         [0054]    In position B of  FIG. 24B , one of the apertures in plane or region  16 - 16  is in alignment or registration with aperture  501 ), which is connected to the flow restrictor tubing  54   b , thereby providing a flow rate of 1.0 ml/hr. The apertures  64  and  68  in planes  15 - 15  and  17 - 17  are out of registration or alignment with ports  50   a  and  50   c , so that no fluid flows through them, and the total flow rate through the valve is 1.0 ml/hr. 
         [0055]    In position C, one of apertures  64  and one of apertures  66  in planes  15 - 15  and  16 - 16  are in alignment or registration with ports  50   a  and  50   b , respectively, which are connected to restrictor tubing  54   a  and  54   b . None of the apertures  68  in plane  17 - 17  is in communication with port  50   c . Thus, the flow rate through the valve is the combined flow of 0.5 ml/hr and 1.0 ml/hr through ports  50   a  and  50   b  for a total flow rate of 1.5 ml/hr. 
         [0056]    The chart in  FIG. 24A  may be followed in similar fashion to see that at position D, flow is only allowed through one of apertures  68  in plane  17 - 17 , at 2.0 ml/hr. In position E, flow is allowed through apertures  64  and  68  in planes  15 - 15  and  17 - 17  (0.5 ml/hr and 2.0° ml/hr) for a combined flow rate through the valve of 2.5 ml/hr. In position F, flow is allowed through apertures  66  and  68  in planes  16 - 16  and  17 - 17  (1.0 ml/hr and 2.0 ml/hr) for a combined flow rate of 3.0 ml/hr. In position G, flow is permitted through one of the apertures  64 ,  66  and  68  in each of planes  15 - 15 ,  16 - 16  and  17 - 17  (0.5 ml/hr, 1.0 ml/hr and 2.0 ml/hr) for a total flow through the device of 3.5 ml/hr. 
         [0057]    At position H and between each of the other positions, no aperture in planes  15 - 15 ,  16 - 16  or  17 - 17  is in communication with its respective port or flow restrictor tubing and there is essentially no flow through the flow control device. 
         [0058]    Although the flow control device is illustrated in its preferred form, many variations are possible without departing from the present invention. For example, additional flow restrictors and flow streams could be provided to offer different flow rates. Also, while in the illustrated embodiment of the present invention, a fluid stream is described as entering the flow control valve through the inlet  34  and exiting through the outlet  36 , it should be understood that the illustrated flow control valve is equally suitable in situations where a fluid stream enters the valve through the outlet  36  and exits the valve through the inlet  34 . Therefore, as used herein, “inlet” and “outlet” are interchangeable and are used only as a naming convention. Thus, the scope of the present invention as described and claimed herein and hereafter is intended to encompass all such operable flow control valves or devices regardless of the name of the part or passage through which fluid enters or leaves the flow control valve. 
         [0059]    It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present subject matter and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.