Abstract:
The present invention relates to a linear flow regulating apparatus for intravenous infusion, and more particularly, to a flow regulating apparatus which is used in an infusion set for intravenous infusion to regulate the flow rate of a solution injected into a body. To eliminate the difficulties caused by the nonlinearity of conventional flow regulating apparatuses, which regulate flow rates by pressing a solution flow tube to adjust the flow passage area, the linear flow regulating apparatus has a control unit to be put in or taken out along the width of a flow channel unit through which the solution flows when the height and length of the flow channel unit are fixed, and is capable of linearly regulating the flow rate by varying the flow passage area of the flow channel unit by adjusting the width of a flow channel unit.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    (a) Field of the Invention 
         [0002]    The present invention relates to a flow regulating apparatus used for an intravenous infusion set (IV set), and more particularly to, a linear flow regulating apparatus which is capable of linearly regulating the flow rate of an infusion solution. 
         [0003]    (b) Description of the Related Art 
         [0004]    As shown in  FIG. 1 , an intravenous injection system for intravenous administration of fluids includes an infusion solution bag  100  containing an infusion solution, an insertion spike  101  adapted to be inserted through a sealing plug of the infusion solution bag  100  to allow the infusion solution to be flown out from the infusion bag  100 , a drip chamber  102  fixed to the lower end of the insertion spike  101  so that the infusion solution can fall in drops (counted in a unit of gtt) within the drip chamber  102 , an injection needle  103  adapted to be inserted into a vein, a connecting tube  104  for interconnecting the drip chamber  102  and the injection needle  103  to serve as an infusion passage for the infusion solution, and an infusion flow regulator  110  mounted in the middle of the connecting tube  104  to be capable of regulating the flow rate of the infusion solution. 
         [0005]    In general, the insertion spike  101 , the drip chamber  102 , the injection needle  103 , the connecting tube  104 , and the infusion flow regulator  110  are fabricated in one set, wherein the set fabricated in this manner is referred to as an infusion set. After the infusion solution in the infusion solution bag  100  connected to the infusion set is completely infused to a patient, only the empty infusion bag  100  may be replaced by a new one containing the same infusion solution if it is necessary to continuously inject the infusion solution to the patient. In addition, the insertion spike  101  and the drip chamber  102  are fabricated to make each of the drops of the infusion solution fall within the drip chamber  102  in the form of a water drop with a predetermined volume. For example, if they are fabricated to form 20 drops per 1 cc of the infusion solution, the volume of one drop will be 1/20 cc. Therefore, if the drops&#39; falling interval within the drip chamber  102  is measured, it is possible to calculate the flow rate of the infusion solution injected through the infusion set. 
         [0006]    For injecting an infusion solution to a patient, the flow rate of the infusion solution is prescribed in consideration of the type of the infusion solution, the kinds of agents mixed in the infusion solution, the condition of the patient, the kind of the disease of the patient, and the infusion flow regulator  110  is tuned so as to allow the infusion solution to be injected with the prescribed flow rate. 
         [0007]    Regulating the flow rate of the infusion solution is very important since a medical accident may occur if the flow rate of the infusion solution being infused is not matched to the prescribed flow rate. Such an infusion flow regulator  110  has a manipulation unit  111  for regulating the cross-sectional area for passage of the infusion solution through the connecting tube  104 , so that the flow rate of the infusion solution can be regulated by manipulating the manipulation part  111 . 
         [0008]    The conventional infusion flow regulator  110  shown in  FIG. 2  is a so-called “roller clamp” type infusion regulator, in which the manipulation unit  111  is formed in a roller type. Referring to the infusion flow regulator  110  in more detail, a connecting tube  104  is inserted through a recess  112  having opened top and bottom ends, and then the manipulation unit  111  adapted to press the connecting tube  104  is guided upward and downward. Since the depth of the recess  112  is gradually reduced toward the lower end, and hence the connecting tube  104  is pressed more and more as the manipulation unit  111  is moved more and more to the lower end of the recess  112 . Thus, the flow rate of infusion fluid is regulated by measuring the flow rate at plural points while intermittently moving the manipulation unit  111 , and by stopping the movement of the manipulation unit  111  when the flow rate reaches a desired level. 
         [0009]    However, the roller clamp type infusion flow regulator  110  shown in  FIGS. 1 and 2  is disadvantageous in that, since the flow rate should be measured while seeing the drip chamber  102  whenever the roller type manipulation unit  111  is moved, complicated measurements (drip rate counts) should be repeatedly performed, which will deteriorate the accuracy of flow rate regulation. 
         [0010]    Moreover, the biggest problem of the conventional roller clamp type infusion flow regulator  110  is that it is difficult to regulate the flow rate. The conventional infusion flow regulator  110  regulates the flow rate by adjusting the flow passage area by pressing the connecting tube  104 . Once the connecting tube  104  is pressed, the cross-section of the connecting tube  104  is deformed from a circular shape to an elliptical shape, and the cross-sectional area and the hydraulic radius of the connecting tube  104  become smaller, thus resulting in a flow reduction. 
         [0011]    According to the Hagen-Poiseuille equation (Hagen-Poiseuille law in pipe) shown in the following Equation 1, which assumes that a flow in a cylindrical tube is steady and laminar, the velocity profile of a fluid flowing within the tube is parabolic, and the flow rate of the fluid is inversely proportional to the length of the tube and proportional to the fourth power of the radius. This results in nonlinear flow regulation, and therefore it is difficult to accurately regulate the flow rate merely by varying the length or radius of the cylindrical tube. 
         [0000]    
       
         
           
             
               
                 
                   Q 
                   = 
                   
                     
                       
                         
                           Δ 
                            
                           
                               
                           
                            
                           p 
                            
                           
                               
                           
                            
                           π 
                            
                           
                               
                           
                            
                           
                             r 
                             0 
                             4 
                           
                         
                       
                     
                     
                       
                         
                           8 
                            
                           
                               
                           
                            
                           μ 
                            
                           
                               
                           
                            
                           1 
                         
                       
                     
                   
                 
               
               
                 
                   Equation 
                    
                   
                       
                   
                    
                   1 
                 
               
             
           
         
       
     
         [0012]    (where Q is the flow rate, r 0  is the radius of the tube, l is the length of the tube, μ is the viscosity of the fluid, and Δp is the pressure difference in the tube.) 
         [0013]    As above, regulating the flow rate by variations in diameter and length is nonlinear and complex even in the cylindrical tube having quite a simple structure. Moreover, variations in the cross-sectional area and length of the flow passage are even more complicated in the roller clamp type flow regulator, making flow regulation more difficult. 
         [0014]    Further, the conventional infusion flow regulator  110  includes the above-mentioned roller clamp type flow regulator, a cylindrical rotary flow regulator, a clock-type flow regulator, a constant infusion pump, etc. Although the roller clamp type flow regulator can vary the flow passage area by a roller, it is not capable of uniformly adjusting the dimension, shape, hydraulic radius, etc of the flow passage area. Therefore, the roller clamp type flow regulator has the drawbacks that it is difficult to regulate the flow rate by the above-mentioned Equation 1, the roller for manipulation is easily moved at a fixed position, and a creep may occur in a deformed tube over time, causing a change in flow rate. 
         [0015]    The rotary flow regulator has a constant cross-sectional area, and is adapted to regulate flow rate by adjusting the length (which is proportional to the angle of rotation) of a capillary tube by turning the dial. The rotary flow regulator also has the problem that it is difficult to regulate the flow rate according to the above-mentioned Equation 1 (the scale is nonlinear because the flow rate is inversely proportional to the length l of the capillary). 
         [0016]    In addition, the constant infusion pump has the problems that it is not convenient to install and use it due to its large size, and runs a high risk of contamination because it is used on many people. 
         [0017]    The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. 
       SUMMARY OF THE INVENTION 
       [0018]    The present invention has been made in an effort to provide a linear flow regulating apparatus for intravenous infusion used in an infusion set or the like for injecting a solution, which has a control unit to be put in or taken out along the width of a flow channel unit through which the solution flows when the height and length of the flow channel unit are fixed, and is capable of linearly regulating the flow rate within the flow channel unit, in proportion to the width, by varying the flow passage area by adjusting the width of the flow channel unit. 
         [0019]    The other objects and advantages of the present invention will be described below and become more apparent by describing exemplary embodiments thereof. Further, the objects and advantages of the present invention will be achieved by elements and a combination of the elements disclosed in the claims. 
         [0020]    An exemplary embodiment of the present invention provides a linear flow regulating apparatus for intravenous infusion, the apparatus including: a flow channel unit having a rectangular cross-section that allows a solution to flow therethrough; and a control unit that is adapted to be put in or taken out of one side of the flow channel unit to vary the flow passage area of the flow channel unit, wherein the control unit may vary the flow passage area while moving along the width of the flow channel unit so as to linearly regulate the flow rate of the solution. 
         [0021]    The linear flow regulating apparatus may further include a fine adjustment unit that is formed at a contact region between the flow channel unit and the control unit to adjust the moving distance of the control unit along the width. 
         [0022]    The fine adjustment unit may include: a plurality of protruding parts formed on an inner peripheral surface of the flow channel unit; and a plurality of coupling parts formed on the outer peripheral surface of the control unit so as to engage the protruding parts. 
         [0023]    A gauge may be formed on one surface of the control unit to check the flow rate of the solution varying with the flow passage area of the flow channel unit when the control unit is put in or taken out. 
         [0024]    The flow channel unit may include: an inlet tube connected at the front end to allow the solution to simultaneously flow in over the entire width of the flow channel unit; and an outlet tube connected at the rear end to allow the solution to simultaneously flow out over the entire width of the flow channel unit. 
         [0025]    The flow channel unit may further include a pinion adjustment unit that is rotatable in meshing engagement with the plurality of coupling parts formed on the outer peripheral surface of the control unit, wherein the control unit may be put into or taken out of one side of the flow channel unit by rotating the pinion adjustment unit. 
         [0026]    The pinion adjustment unit may include: a pinion part meshing with the coupling parts; and a fixing part for fixing the pinion part to the outer peripheral surface of the flow channel unit. 
         [0027]    As discussed above, the linear flow regulating apparatus for intravenous infusion in accordance with the present invention has the advantage of enabling accurate flow regulation by linearly regulating the flow rate of a solution. The present invention makes it possible to quickly and accurately regulate the flow rate to a desired level by calibrating the number of drops from a drop chamber once, since the flow rate of the solution is maintained linear. 
         [0028]    Moreover, the present invention has the advantage of simple configuration and ease use because the control unit is configured to be put in or taken out along the width of the flow channel unit. 
         [0029]    Further, the present invention has the advantage of cutting down production costs, increasing production yield, and reducing costs incurred during production. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]      FIG. 1  is a perspective view showing an example of a conventional infusion solution bag. 
           [0031]      FIG. 2  is a front cross-sectional view showing an example of the structure of a conventional roller clamp type infusion flow regulator shown in FIG. 
           [0032]      FIG. 3  is an exploded perspective view showing a linear flow regulating apparatus for intravenous infusion in accordance with the present invention. 
           [0033]      FIG. 4  is a perspective view of  FIG. 3 . 
           [0034]      FIG. 5  is a view taken along the line A-A of  FIG. 4   
           [0035]      FIG. 6  is a perspective view showing an infusion set to which a linear flow regulating apparatus for intravenous infusion in accordance with an exemplary embodiment of the present invention. 
           [0036]      FIG. 7  is a planar cross-sectional view showing a pinion adjustment unit in accordance with an exemplary embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0037]    Before exemplary embodiments of the present invention are described in detail, it will be understood that, detailed constitution and arrangements of elements described in the detailed description or illustrated in the drawings should not be construed as limiting the application of the invention. The invention may be embodied in many alternate forms and performed in various methods. 
         [0038]    The terms or words to describe the direction of an apparatus or element (for example, “front”, “back”, “up”, “down”, “top”, “bottom”, “left”, “right” and “lateral”, among others) are used to simplify the description of the invention. It will be, therefore, understood that these terms do not mean that the relevant apparatus or element shall be only in the specific direction. 
         [0039]    The present invention has the following features to attain the aspect mentioned above. 
         [0040]    The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. It will be understood that words or terms used in the specification and claims shall not be interpreted as the meaning defined in commonly used dictionaries. It will be further understood that the words or terms should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the technical idea of the invention, based on the principle that an inventor may properly define the meaning of the words or terms to best explain the invention. 
         [0041]    Therefore, configurations described in embodiments and shown in drawings of the present specification indicate only the most preferred example rather than indicating all the technical ideas of the present disclosure and therefore, it is to be understood that various equivalents and modifications that can replace the above configurations may be present. 
         [0042]    Hereinafter, a linear flow regulating apparatus for intravenous infusion in accordance with an exemplary embodiment of the present invention will be described in detail with reference to  FIGS. 1 to 7 . 
         [0043]    Referring to  FIG. 4 , the linear flow regulating apparatus  70  for intravenous infusion according to the present invention includes a flow channel unit  10 , a control unit  20 , a fine adjustment unit  30 , and a gauge  40 . 
         [0044]    The flow channel unit  10  is hollow inside, and its front and rear ends have an open rectangular cross-section. In the present invention, the height of the flow channel unit  10  is denoted by ‘h’, its length is denoted by ‘l’, and its width is denoted by ‘b’, where the width b is much greater than the height (b&gt;&gt;h), making the flow channel unit  10  in a rectangular shape. 
         [0045]    By ignoring end wall effects, the Hagen-Poiseuille law in channel can be applied as shown in the following Equation 2. 
         [0000]    
       
         
           
             
               
                 
                   Q 
                   = 
                   
                     
                       Δ 
                        
                       
                           
                       
                        
                       
                         ph 
                         3 
                       
                        
                       b 
                     
                     
                       12 
                        
                       
                           
                       
                        
                       μ 
                        
                       
                           
                       
                        
                       1 
                     
                   
                 
               
               
                 
                   Equation 
                    
                   
                       
                   
                    
                   2 
                 
               
             
           
         
       
     
         [0046]    (where Q is the flow rate, Δp is the pressure difference in the channel (flow channel unit  10 ), h is the height of the channel, b is the width of the channel, μ is the viscosity of the fluid, and l is the length of the channel.) 
         [0047]    That is, it can be seen that, while adjusting the area by pressing the conventional connecting tube  104 , as shown in  FIG. 2  depicting the conventional infusion flow regulator, does not contribute to linear regulation of flow rate by Equation 1 set forth in [Background of the Invention], the flow rate in the flow channel unit  10  having a rectangular cross-section is inversely proportional to the length l, proportional to the third power of the height h, and linear to the width b. 
         [0048]    According to the present invention, the height h and length l of the flow channel unit  10  are fixed and the width b of the flow channel unit  10  is adapted to be controlled by the control unit  20  to be described later. Therefore, the flow rate can be linearly and accurately regulated by controlling the width b of the flow channel unit  10 , which is linear to the flow rate (Q (flow rate) ∝b (width)). 
         [0049]    Moreover, an inlet tube  51  and an outlet tube  52  are connected at the open front and rear ends of the flow channel unit  10  so as to allow a solution N to flow therethrough. The inlet tube  51  is disposed at the front end of the flow channel unit  10 , and the outlet tube  52  at the rear end of the flow channel unit  10 , so that the solution flowing from the inlet tube  51  migrates to the outlet tube  52  through the inside of the flow channel unit  10 . 
         [0050]    An expanding or contracting tube portion  53  is formed such that ends of the inlet tube  51  and outlet tube  52  having a circular cross-section respectively correspond to the front and rear ends of the flow channel unit  10  communicating with each other. Thus, the solution entering from the inlet tube  51  simultaneously flows in over the entire width b of the front end of the flow channel unit  10 . 
         [0051]    Also, the solution flowing out through the inlet tube  51  and the flow channel unit  10  simultaneously exits over the entire width b of the rear end of the flow channel unit  10 . 
         [0052]    Referring to  FIG. 5 , the control unit  20  is configured to be inserted into one side of the flow channel unit  10 , and has a rectangular cross-sectional shape corresponding to the flow channel unit  10 . 
         [0053]    With this configuration, the control unit  20  may be put in or taken out along the width b of the flow channel unit  10  by the user, when the control unit  20  is inserted corresponding to one side of the flow channel unit  10 . 
         [0054]    That is, as the flow passage area of the flow channel unit  10  decreases when the control unit  20  is put in, and the flow passage area of the flow channel unit  10  increases when the control unit  20  is taken out (the flow channel unit  10  is not fully removed from the control unit  20 ), the flow rate in the flow channel unit  10  can be regulated. 
         [0055]    In other words, the control unit  20  is inserted into one side of the flow channel unit  10  so as to correspond to and come in contact with the inside of the flow channel unit  10  whose height h and length l are fixed, whereby the flow rate of the solution through the flow channel unit  10  can be regulated while moving the control unit  20  along the width b of the flow channel unit  10 . 
         [0056]    Moreover, as the flow passage area of the flow channel unit  10  is linear (proportional) to the width b, as described above, the flow rate of the solution through the flow channel unit  10  of the present invention is linearly adjusted with the same amount as the width b of the flow channel unit  10 . As a result, the linear flow regulating apparatus for intravenous infusion according to the present invention is able to accurately regulate the flow rate of an infusion solution when applied to an infusion set. 
         [0057]    As described above, the fine adjustment unit  30  is for finely adjusting the moving distance of the control unit  20  put in or taken out along the width b of the flow channel unit  10 . 
         [0058]    The fine adjustment unit  30  includes protruding parts  11  and coupling parts  21 . 
         [0059]    The protruding parts  11  may consist of one or more protrusions protruding on an inner peripheral surface of the flow channel unit  10 . If the protruding part  11  consists of two protrusions, the protrusions are spaced apart from each other on an inner peripheral surface of the flow channel unit  10 . 
         [0060]    The coupling parts  21  are formed on the outer peripheral surface of the control unit  20  so as to engage the protruding parts  11 . 
         [0061]    More specifically, as the control unit  20  is put into or taken out of one side of the flow channel unit  10 , the above-described protruding parts  11  are formed along the width b (in the movement direction of the control unit  20 ) on a region contacting the outer peripheral surface of the control unit  20 , i.e., on the inner peripheral surface of the flow channel unit  10 , and the above-described coupling parts  21  are formed along the width b (in the movement direction of the control unit  20 ) on a region contacting the inner peripheral surface of the flow channel unit  10 , i.e., on the outer peripheral surface of the control part  20 . 
         [0062]    If the plurality of coupling parts  21  formed on the control part  20  sequentially and bilaterally engage the protruding parts  11 , like gears, and then the control unit  20  is put in along the width b of the flow channel unit  10 , this means that the plurality of coupling parts  21  are inserted between some of the protruding parts  11  along the width b and then between another protruding parts  11  in a repetitive fashion. 
         [0063]    That is, the moving distance of the control unit  20  along the width b is accurately adjusted as the distance between the protruding parts  11  or the distance between the coupling parts  21  changes (ex: a decrease or increase of 10 cc/hr each time the coupling parts  21  move one space), so that the flow passage area of the flow channel unit  10  can be accurately varied. 
         [0064]    While the protruding parts  11  and the coupling parts  21  are configured to protrude outward, various changes can be made, including the protruding parts  11  configured to be put in and the coupling parts  21  configured to engage the protruding parts  11  in a male-female relation, according to a variety of exemplary embodiments, as long as the moving distance of the control unit  20  along the width b can be accurately and sequentially adjusted. 
         [0065]    The gauge  40  is formed along the width b (in the movement direction of the control unit  20 ) on one surface of the control unit  20  that is put into or taken out of the flow channel unit  10 . By checking a measurement on the gauge  40  corresponding to one edge of the flow channel unit  10  whenever the control unit  20  is put into or taken out of the flow channel unit  10  by means of the fine adjustment unit  30 , the user is able to find the flow rate through the variable flow passage of the flow channel unit  10 , based on the measurement on the gauge  40 . 
         [0066]    The gauge  40  has no protrusion, and serves to prevent a solution from migrating along the length l from the control unit  20  through the protruding parts  11 . 
         [0067]    Referring to  FIG. 7 , a pinion adjustment unit  60  includes a fixing part  61 , one end of which being fixed to the outer peripheral surface of the flow channel unit  10  and the other end of which extending toward the control unit  20 , a reference axis  62  formed at the center of a circular-shaped body, with the fixing part  61  being fixed to the reference axis  62 , and a pinion part  64  having a plurality of gears  63  formed on the outer circumference, and meshing with the plurality of coupling parts  21  formed on the outer peripheral surface of the control unit  20 . 
         [0068]    That is, a plurality of gears  63  are formed on the outer circumference of the pinion part  64 , and the gears  63  may mesh with the plurality of coupling parts  21  formed on the outer peripheral surface of the control unit  20 . 
         [0069]    In this case, the user may put or take the control unit  20  into or out of the flow channel unit  10  by directly pushing or pulling the control unit  20 . Otherwise, the user may put or taken the control unit  20  into or out of the flow channel unit  10  in the rotating direction of the pinion part  64  by rotating the pinion part  64 , because the gears  63  formed on the outer circumference of the pinion part  64  mesh with the coupling parts  21  of the control unit  20 . 
         [0070]    In other words, if the pinion adjustment unit  60  consisting of the fixing part  61  and the pinion part  64  is rotated counterclockwise, the gears  63  of the pinion part  64  push the control unit  20  toward the flow channel unit  10 , thus causing the control unit  20  to be put into the flow channel unit  10 . 
         [0071]    On the contrary, if the pinion adjustment unit  60  is rotated clockwise, the gears  63  of the pinion part  64  pulls the control unit  20  outward of the flow channel unit  10 , thus causing the control unit  20  to be taken out of the flow channel unit  10 . 
         [0072]    While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.