Abstract:
A tap valve selectively taps a line while maintaining fluid continuity within the line. The valve comprises a throughput tube and a tapping port which terminates at a rotatable member. The rotatable member has a generally circular cross section and may be oriented either to provide fluid communication between the throughput tube and tapping port or to seal off the tapping port.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to valves, and particularly to medical valves. 
     In many applications, particularly medical applications, it is desirable to selectively tap a throughput line while maintaining fluid continuity within the line, for the purposes of sampling or monitoring fluid in the line or injecting another fluid into the line. For example, U.S. Pat. No. 4,673,386, issued to Gordon, discloses a device for drawing blood samples from an I.V. line attached to a patient. The device disclosed by Gordon, however, is relatively complex and expensive to manufacture. Further, the valving system of Gordon is a special purpose device directed only to blood sampling. 
     Accordingly, there is a need in the art for a relatively inexpensive valve which selectively taps a throughput line for a variety of applications such as blood sampling, fluid pressure monitoring and drug infusion. 
     SUMMARY OF THE INVENTION 
     The present invention comprises a tap valve having a throughput tube and a housing which form a valve body. Preferably, the housing and throughput tube are integrally formed as a single unit. The throughput tube provides a fluid flow channel between first and second ends. The housing mounts a rotatable valve member that is in fluid communication with the fluid flow channel at a predetermined location, such that an exterior surface of the rotatable member is laterally spaced from an interior wall of the fluid flow channel at the predetermined location to permit fluid flow therebetween. The rotatable member is mounted along an axis of rotation which is offset from the Iongitudinal axis of the throughput tube, and the rotatable valve member has a generally circular cross section. 
     The housing further includes a tapping port having an end which terminates at the rotatable member. The rotatable member has multiple positions, including a first position for orienting a passage to enable fluid flow between the throughput tube and the tapping port without closing off the fluid flow channel at the predetermined location. The rotatable member also has a second position which seals the tapping port to disable fluid flow between the throughput tube and the tapping port without closing off the fluid flow channel at the predetermined location. 
     The invention also comprises a method of selectively tapping fluid from a throughput tube. The method includes the step of rotating a rotatable member to orient a passage for fluid communication between the throughput tube and a tapping port without disabling the fluid flow through the tube. The rotatable member is additionally rotated to orient the passage for fluid communication exclusively with the throughput tube without closing off the fluid flow through the tube, and a portion of the fluid flow in the throughput tube is passed through the passage to prevent stagnation of the fluid in the passage. Such method is useful, for example, in obtaining blood samples from an I.V. line attached to a patient. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     These and other features of the present invention may be more fully understood through reference to the drawings in which: 
     FIG. 1 is a perspective view of the tap valve of the present invention; 
     FIG. 1a is a perspective view of the rotatable member and handle, showing the groove in the rotatable member which provides a selectively oriented passage between ports of the valve; 
     FIG. 2 is a cross-sectional view, taken along the lines 2--2 of FIG. 1, showing the rotatable member partially intercepting the fluid flow channel and further showing the rotatable member in an &#34;idle&#34; position which prevents fluid communication between the throughput tube and either of the tapping ports; 
     FIG. 3 is a cross-sectional view, taken along the same lines as FIG. 2, showing the rotatable member oriented to provide fluid communication between the throughput tube and one of the tapping ports; 
     FIG. 4 is a cross-sectional view, taken along the same lines as FIG. 2, showing the rotatable member oriented for fluid communication between the two tapping ports; 
     FIG. 5 is a cross-sectional view, taken along the same lines as FIG. 2, showing the rotatable member oriented for fluid communication between the throughput tube and the other of the tapping ports; 
     FIG. 6 is a schematic drawing illustrating use of the tap valve to obtain blood samples from a patient; 
     FIG. 7 is a plan view in partial cross section showing an alternative embodiment of the tap valve of the present invention in which the tap valve provides fluid communication between either of two lines and a pressure transducer; and 
     FIG. 8 is a plan view of the tap valve of FIG. 1 showing indicia for designating fluid flow paths through the tap valve. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As shown in FIGS. 1-5, the tap valve 10 of the present invention comprises a valve body 11 having throughput tube 12 with a central longitudinal axis 13. The tube 12 includes ends 14, 16 which form inlet or outlet ports, and a fluid flow channel 17 for carrying fluid in either direction between the ports 14, 16. Connectors 18, 20 are provided at the ports 14, 16, respectively, to permit connection of the throughput tube 12 to, for example, an I.V. line. In the preferred embodiment, the connectors 18, 20 are formed as male and female luer fittings, respectively. 
     The valve body 11 additionally comprises a housing 24 on which the throughput tube 12 is mounted. In the preferred embodiment, the housing 24 is integrally formed with the throughput tube 12 such that the valve body 11 is a single unitary structure. The housing 24 comprises a cylindrical member having a longitudinal bore 26 (FIG. 2) therein. The bore 26 has a central longitudinal axis 28 which is (a) orthogonal to the central longitudinal axis 13 of the throughput tube 12 and (b) laterally displaced therefrom by a distance D. In the preferred embodiment, the distance D is greater than the radius of the fluid flow channel 17, and is approximately equal to the radius of the bore 26. 
     The housing 24 includes two ports 30, 32 comprising tubes having central longitudinal axes 34, 36, respectively, which pass through the central longitudinal axis 28 of the bore 26 in a direction orthogonal to the axis 28. In the preferred embodiment, the axes 34, 36 are disposed at approximately 45° relative to the axis 13. The ports 30, 32 are formed as female luer fittings having terminal end openings 40, 42, respectively, which provide fluid flow openings at the bore 26 for fluid communication therebetween, and distal end openings 44, 46, respectively, which are sized to receive the output end of a syringe. The distal end openings 44, 46 are enlarged relative to the terminal end openings 40, 42, respectively. Tapered wall portions 48, 50, respectively, provide transitions between the distal ends and terminal ends. Although the ports 30, 32 of the preferred embodiment are configured as luer fittings which accept syringes, it will be understood that alternative configurations could be used for connecting other devices or tubes. 
     A rotatable core member 60 having a central longitudinal axis coincident the with the axis 28 is mounted in the bore 26 for rotation about the axis 28. The member 60 is generally cylindrical and has a diameter substantially equal to the inside diameter of the bore 26 so as to fluidly seal the rotatable member 60 against the interior sides of the bore 26. The radius of the rotatable member 60 is approximately equal to the distance D, such that the rotatable member projects through an opening 61 in the inner side wall of the throughput tube 12 and into the fluid flow channel 17 formed by the throughput tube 12. The rotatable member only partially intercepts the fluid flow channel 17 so as to allow continuous fluid flow along the axis 13 through an opening or passageway 62 between the exterior surface of the rotatable member 60 and an interior surface of the throughput tube 12. 
     As best seen in FIG. 1a, the rotatable member 60 includes a groove 64 on one side thereof, which extends through about 90° of circumference of the rotatable member 60, and is disposed between end surfaces 66, 68 of the cylindrical rotatable member 60 such that, when mounted in the bore 26, the groove 64 is aligned with the fluid flow channel 17 of the throughput tube 12. In other words, the groove 64 lies in a plane defined by the opening 61 in the tube 12 and the terminal end openings 40, 42 of the ports 30, 32. The groove 64 has a longitudinal axis 63 which is orthogonal to and spaced from the axis of rotation 28. The length of the groove 64 is approximately equal to the length of the opening 61 in the throughput tube 12 in which the rotatable member 60 is mounted, and the width of the groove 64 is approximately equal to the diameter of the terminal end openings 40, 42 of the ports 30, 32, respectively. The depth of the groove 64 at the center thereof (i.e., at the midpoint of its length) is approximately equal to the radius of the fluid flow channel 17. The groove 64 comprises a bottom wall 65a and side walls 65b, 65c. The side walls 65b, 65c extend to the exterior surface of the rotatable member 60 such that the groove is open along its length and has the appearance of a notch or cut-out. This configuration permits substantially optimum flow with minimum obstructions between the ports 30, 32 and the tube 12. 
     A handle 70 comprises an elongate bar-shaped member having a top surface 67a, side surfaces 67b, 67c and a bottom surface 67d. The bottom surface 67d is attached to the end surface 66 of the rotatable member 60 such that the surface 66 is substantially beneath the surface 67a. The elongate member 70 has a longitudinal dimension which is preferably oriented to project away from the groove 64 in a direction perpendicular to the axis of rotation 28. 
     The handle 70 may be used to facilitate rotation of the member 60 and to orient the rotatable member to any of four preferred positions, as shown in FIGS. 2, 3, 4 and 5. When the handle is oriented in the position shown in FIG. 2, the groove 64 is disposed within the fluid flow channel 17. In this &#34;idle&#34; position, the longitudinal axis 63 (FIG. 1a) of the groove 64 is substantially parallel to the longitudinal axis 13 of the throughput tube 12 and thus, fluid flowing through throughput tube 12 will continuously flow along the walls 65 of the groove 64 and thereby flush the interior of the groove 64 to prevent fluid from stagnating therein. 
     When the handle 70 is rotated 90° to the position shown in FIG. 3, one end of the groove 64 is open to the throughput tube 12, and the other end of the groove 64 is open to the terminal end opening 40 of the tapping port 30. The groove 64 thus provides a passage for fluid communication between the tapping port 30 and the throughput tube 12. The passageway is formed by the surfaces 65 of the groove 64 and an interior surface portion of the bore 26. In this &#34;tapping&#34; position, fluid may be tapped from the throughput line 12 to the port 30, or injected through the port 30 into the throughput line 12. 
     Rotation of the handle 70 by an additional 90° orients the groove 64 to provide a passage for fluid communication between the tapping ports 30, 32, as shown in FIG. 4. In this position, fluid from one port may be injected into the other port. 
     Further rotation of the handle 70° by 90° orients the groove 64 to provide a passageway for fluid communication between the tapping port 32 and the throughput tube 12. It will be understood that the valve may be rotated in either a clockwise or counterclockwise direction to achieve the above positions. 
     The valve of the present invention is suitable for a variety of applications. One such application involves drawing blood from a patient through an I.V. line connected to a supply of I.V. solution. As shown schematically in FIG. 6, the ends 14, 16 of the throughput tube 12 may be attached to I.V. line segments 80, 82, respectively Typically, the line segment 82 would be connected to a source of I.V. solution, and the line segment 80 would be connected to deliver such solution into a patient. When the tap valve 10 of the present invention is in its &#34;idle&#34; position, depicted in FIG. 2, the I.V. solution would flow through the segment 82, into the valve 10, through the valve 10 into the segment 80, and through the segment 80 into the patient. 
     When a blood sample from the patient is desired, the I.V. line 82 is preferably clamped to prevent flow therethrough, and the handle 70 is rotated to the tapping position depicted in FIG. 5 so as to provide fluid communication between the port 16 and the tapping port 32. A syringe 84, connected to the tapping port 32, is used to draw fluid from the throughput line 12 through the tapping port 32. Such drawing of fluid causes blood to be drawn from the patient through the line segment 80. The drawing of blood is continued until undiluted blood from the patient reaches at least the opening 62 in the throughput tube 12. The handle 70 is then rotated to the tapping position shown in FIG. 3 to fluidly connect the throughput tube 12 to the tapping port 30. A second syringe 86 is then used to draw blood from the throughput tube 12 through the tapping port 30 and into the syringe 86 to provide an undiluted blood sample for analysis. Preferably, the handle 70 is then rotated back to the tapping position shown in FIG. 5, and the fluid drawn into the syringe 84 is reinjected into the throughput tube 12 and carried to the patient by the line 80. Finally, the handle 70 may be returned to the &#34;idle&#34; position shown in FIG. 2. In this position, the passage formed by the groove 64 is exposed to flow of I.V. solution through the throughput tube 12, and any blood remaining in the passage 64 will be flushed out by flow of I.V. solution through the throughput tube 12. 
     FIG. 7 illustrates another embodiment of the invention which utilizes the tap valve to selectively monitor either of two fluid flow lines 90, 92 with a single sensor 94. In this embodiment, a pair of throughput tubes 96, 98 are disposed on opposite sides of a rotatable member 100 having a groove 102. The sensor 94 is disposed at a port 104, between the throughput tubes 96, 98 such that the groove 102 provides a passage for fluid communication between either the port 104 and the throughput tube 96 or the port 104 and the throughput tube 98. In such manner, a single sensor can be used to monitor either of two lines, thereby eliminating the need for two sensors. In the embodiment disclosed, the sensor 94 comprises a pressure transducer which is connected to electronics 106 by wires 108. The lines 90, 92 are attached to ends of the throughput tubes 96, 98, respectively, by cementing the lines 90, 92 into slip-fit connectors. The other ends of the throughput tubes 96, 98 include male luer fittings 112, 114, respectively, with associated luer nuts 116, 118, respectively. The distal end of the lines 90, 92 include female luer fittings 120, 122. 
     As shown in FIG. 8, the valve 10 includes indicia for designating the fluid flow paths through the valve for the various handle orientations shown in FIGS. 2-5. In the preferred embodiment, indicia are disposed on raised portions 202, 204, 206, adjacent the periphery of the rotatable member 60. The raised portion 204 comprises an elongate member which is longitudinally aligned with the longitudinal axis 34 of the port 30, and the raised portion 206 comprises an elongate member which is longitudinally aligned with the longitudinal axis 36 of the port 32. The members 204, 206 have corresponding surfaces 210 and 214, both of which are coplanar with the surface 66 of the rotatable member 60. The raised portion 202 includes a pair of elongate members 220, 222 and an arcuate member 224 which extends between the elongate members 220, 222. The arcuate member 224 abuts the peripheral edge of the surface 66 of the rotatable member 60 through 90 of circumference of the rotatable member 60. The elongate members 220, 222 are longitudinally aligned with the longitudinal axis 13 of the throughput tube 12, and are disposed along the end portions 14, 16, respectively of the throughput tube 12. The members 220, 222 and 224 have corresponding surfaces 226, 228 and 230, respectively, all of which are coplanar with the surface 66 of the rotatable member 60. Preferably, all of the surfaces 210, 214, 226, 228 and 230 are colored so as to visually distinguish these surfaces from the remainder of the valve 10. 
     The surface 66 of the rotatable member 60 comprises fluid path indicia at a location which corresponds to that of the groove 64 (FIG. 1a). In the preferred embodiment, the indicia comprises a colored strip 240, shaped in the form of circular segment, having an arcuate boundary 250 at a peripheral edge of the surface 66, and a chord boundary 252 which lies along a chord of the circle formed by the peripheral edge of the surface 66. The colored strip 240 has approximately the same dimensions and configuration as the side surfaces 65b, 65c forming the groove 64, and extends through 90° of circumference of the rotatable member 60. Thus, the colored strip 240 follows a continuous path on the surface 66 which substantially duplicates the fluid flow path formed by the passage 64 so as to indicate the direction and extent of the fluid flow path. Preferably, the colored strip 240 is of the same color as the surfaces 210, 214, 226, 228 and 230. 
     The handle 70 extends longitudinally in a direction away from the colored strip 240, as indicated in FIG. 1, so that the handle does not cover or inhibit viewing the colored strip. For clarity of illustration of the indicia, the handle 70 has not been shown in FIG. 8. In the preferred embodiment, the handle 70 projects above the surface 66 such that the bottom surface 67d of the handle 70 is above the surfaces 210, 214, 226, 228 and 230 in order to clear these surfaces and thereby permit rotation of the handle through 360° in a plane of rotation which is perpendicular to the axis of rotation 28 of the rotatable member 60. The plane of rotation of the handle 70 is above the surfaces 66, 210, 214, 226, 228 and 230 such that the fluid path indicia 240 is disposed between the plane of rotation of the handle 70 and the passage 64. 
     When the handle 70 is oriented in a direction corresponding to the handle position of FIG. 2, the colored strip 240 is disposed adjacent to the arcuate surface 230, as shown in FIG. 8, and blends into the colored surfaces 226, 228, 230 so as to designate the &#34;idle&#34; position. In this position, there is no fluid communication between the throughput tube 12 and either of the tapping ports 30, 32. When the rotatable member 60 is rotated 90° clockwise from the &#34;idle&#34; position, such that the chord boundary 252 coincides with the dotted line 254 in FIG. 8, the passage formed by the groove 64 (FIG. 1a) will be oriented to correspond to that shown in FIG. 3, so as to provide fluid communication between the throughput tube 12 and tapping port 30. In this position, the colored strip 240 will extend between the surface 210 and the surface 226 to designate fluid communication between the tube 12 and port 30. Similarly, when the rotatable member is rotated counterclockwise from the &#34;idle&#34; position by 90°, such that the chord boundary 252 coincides with the dotted line 256 in FIG. 8, the passage 64 will be oriented as shown in FIG. 5, and the colored strip will extend between the surface 228 and the surface 214, thereby indicating fluid communication between the tube 12 and tapping port 32. Finally, when the rotatable member 60 is rotated 180° relative to the &#34;idle&#34; position, such that the chord boundary 252 coincides with the dotted line 258 in FIG. 8, the colored strip 240 will extend between the elongate surfaces 210, 214, thereby indicating fluid communication between the two ports 30, 32. 
     Accordingly, the indicia on the tube 12, tapping ports 30, 32 and rotatable member 60 cooperate to provide a highly visible map of the passageways within the valve and readily indicate the selectable fluid connections between ports of the valve. 
     Those skilled in the art will understand that although exemplary uses have been described, the tap valve of the present invention is a multi-purpose device suitable for a variety of uses, including drug infusion. Moreover, it is to be understood that the constructions described and illustrated above in connection with the tap valve represent only the presently preferred embodiments of the invention, and that various modifications and additions may be made to those embodiments without departing from the scope and spirit of the present invention.