Patent Publication Number: US-2023157576-A1

Title: Mouthpiece assembly for respiration measurement device

Description:
TECHNICAL FIELD 
     The present invention relates to a mouthpiece assembly for a respiration measurement device, and more particularly to a hygienic and economical mouthpiece for a respiration measurement device capable of being applied to a device configured to measure respiration of a user. 
     BACKGROUND ART 
     In general, a respiration measurement device is a device configured to measure and analyze respiration volume and lung capacity of a user, and is an essential tool for lung health management. The respiration measurement device may include a respiration tube, that is, a mouthpiece placed in the mouth of a user and configured to allow the user to breathe in and out therethrough in order to analyze respiration volume of the user. 
     This mouthpiece should be harmless to the human body because the same is a component which directly touches a user&#39;s mouth, and is mainly manufactured by injection-molding a medical plastic material, thereby making it possible to maintain the shape thereof when used and to secure durability thereof. 
     Meanwhile, this mouthpiece is required to consider health and hygiene because a user directly touches the same and blows his or her breath therein to. Therefore, this mouthpiece is used as a disposable component and is discarded after the user uses the mouthpiece. 
     However, since such a mouthpiece of the related art is made of a medical plastic material requiring high manufacturing costs, there is a problem in that the burden of manufacturing costs is inevitably increased and economic feasibility deteriorates accordingly. 
     DISCLOSURE 
     Technical Problem 
     Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a mouthpiece assembly for a respiration measurement device capable of maintaining hygiene thereof and reducing economic burden by using a material that is not only harmless to the human body, but also economical and easy to manufacture. 
     Technical Solution 
     In accordance with the present invention, the above and other objects can be accomplished by the provision of a mouthpiece assembly for a respiration measurement device, the mouthpiece assembly including a first main body including a respiration measurement module, and a mouthpiece detachably coupled to the first main body, wherein the mouthpiece includes a tube adapter having a cylindrical tube shape, wherein the tube adapter has a first seating surface formed on an inner peripheral surface or an outer peripheral surface of one end thereof, and an insertion hole formed to penetrate an outer peripheral side surface thereof, wherein the respiration measurement module is inserted into the insertion hole when the tube adapter is coupled to the first main body, wherein the insertion hole is shielded when the respiration measurement module is inserted into the insertion hole, and a first tube having a cylindrical tube shape, wherein the first tube has one end thereof detachably coupled to the one end of the tube adapter, and one side surface thereof contact-coupled to the first seating surface when coupled to the tube adapter, wherein the respiration measurement module has a first differential pressure generation portion formed to protrude from an inner peripheral surface thereof, wherein the first differential pressure generation portion has a predetermined thickness and height in a circumferential direction of passing through the insertion hole, and wherein the tube adapter has a second differential pressure generation portion formed to protrude from an inner side surface thereof, wherein the second differential pressure generation portion has a predetermined thickness and height corresponding to the first differential pressure generation portion. 
     Advantageous effects 
     A mouthpiece assembly for a respiration measurement device according to the present invention includes a mouthpiece partially formed with a material that is harmless to the human body and economical, thereby making it possible to maintain hygiene thereof and reduce manufacturing costs. Accordingly, economic effects may be achieved through the mouthpiece assembly. 
     Further, in the mouthpiece assembly for the respiration measurement device according to the present invention, a portion of the mouthpiece coupled to a first main body is made of a durable medical plastic material, and the rest thereof is made of an inexpensive paper material that is harmless to the human body, thereby making it possible not only to reduce manufacturing costs, but also to provide economic effects because manufacturing is easy. 
     In addition, since the mouthpiece assembly for the respiration measurement device according to the present invention has a simple structure and may be miniaturized, it is possible to easily measure respiration volume of a subject regardless of time and place, as well as at home or in a hospital. The mouthpiece assembly includes the first main body including a respiration measurement module and a mouthpiece having an air flow path formed therein, the air flow path having air flowing there through. Here, the first main body and the mouthpiece are separately formed and configured to be detachable from each other, thereby making it possible to easily remove foreign substances remaining in the sensor of the respiration measurement module and the air flow path. Accordingly, it is possible to provide an effect of easily maintaining a hygienic state of the mouthpiece assembly. 
     Additionally, the mouthpiece assembly for the respiration measurement device according to the present invention may increase sensing sensitivity through a first differential pressure generation portion and a second differential pressure generation portion. Further, since the mouthpiece assembly has a simple structure, the same may improve performance and provide economic effects. 
     Further, the mouthpiece assembly for the respiration measurement device according to the present invention includes the first main body including the respiration measurement module configured to measure respiratory airflow and the mouthpiece having an air flow path through which the respiratory airflow moves. Here, since the first main body and the mouthpiece are separately formed and configured to be detachable from each other, the same may be easily replaced after use by a user and efficiently managed in a hygienic manner. 
    
    
     
       DESCRIPTION OF DRAWINGS 
       The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG.  1    is an exploded perspective view showing a mouthpiece assembly for a respiration measurement device according to an embodiment of the present invention; 
         FIG.  2    is an exploded perspective view showing a bottom portion of a first main body in the mouthpiece assembly for the respiration measurement device in  FIG.  1   ; 
         FIG.  3    is a front cross-sectional view showing the inside of the mouthpiece assembly for the respiration measurement device in  FIG.  1   ; 
         FIG.  4    is an exploded perspective view showing another embodiment of a mouthpiece in the mouthpiece assembly for the respiration measurement device in  FIG.  1   ; 
         FIG.  5    is a front cross-sectional view showing the inside of the mouthpiece in  FIG.  4   ; 
         FIG.  6    is a perspective view showing another embodiment in which a filter unit is provided in a tube adapter in the mouthpiece in  FIG.  4   ; 
         FIG.  7    is a cross-sectional view showing the principle of measuring respiration volume through a first pressure generation portion and a second pressure generation portion in the mouthpiece assembly for the respiration measurement device in  FIG.  1   ; 
         FIG.  8    is an exploded perspective view showing another embodiment of a third coupling portion and a fourth coupling portion in the mouthpiece assembly for the respiration measurement device in  FIG.  1   ; 
         FIG.  9    is an exploded perspective view showing in detail the configuration of the third coupling portion and the fourth coupling portion in the mouthpiece assembly for the respiration measurement device in  FIG.  8   ; 
         FIG.  10    is a perspective view showing a bottom surface of a first main body in the mouthpiece assembly for the respiration measurement device in  FIG.  8   ; 
         FIG.  11    is an exploded perspective view showing another embodiment of the third coupling portion and the fourth coupling portion in  FIG.  9   ; 
         FIG.  12    is a perspective view showing a case in which a rotation prevention portion is provided in the mouthpiece assembly for the respiration measurement device in  FIG.  1   ; and 
         FIG.  13    is a front cross-sectional view showing a case in which an insertion groove portion is formed in the mouthpiece assembly for the respiration measurement device in  FIG.  1   . 
     
    
    
     BEST MODE 
     Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings so as to explain the present invention in more detail. 
     Since the present invention may have various modifications and embodiments, specific embodiments are illustrated in the drawings and described in detail. However, it is not intended to limit the present invention to the specific embodiments, and it should be understood that the specific embodiments cover all modifications, equivalents, and substitutes within the spirit and technical scope of the present invention. 
     Terms such as “first”, “second”, and the like may be used herein to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another component. For example, a first component may be referred to as a second component and, similarly, a second component may be referred to as a first component without departing from the scope of the present invention. Terms such as “and/or” include a combination of a plurality of related described items or any one of a plurality of related described items. 
     It will be understood that, when an element is referred to as being “connected” or “joined” to another element, the element may be directly connected or joined to the other element, but it should be understood that any intervening element may also be present there between. In contrast, when an element is referred to as being “directly connected” or “directly joined” to another element, it should be understood that no intervening element is present there between. 
     The terms used in the present application are used only to describe specific embodiments and are not intended to limit the present invention. Singular forms are intended to include plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “includes”, and/or “has”, when used in the present application, specify the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof. 
     Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as those generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having meanings consistent with those in the context of the related art. Unless explicitly defined in the present application, the terms are not interpreted in an ideal or overly formal sense. In addition, in order to facilitate the overall understanding in describing the present invention, the same components in the drawings are denoted by the same reference numerals, and duplicate descriptions of the same components are omitted. 
     Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. 
     Referring to  FIG.  1   , a mouthpiece assembly for a respiration measurement device according to an embodiment of the present invention may be formed of a first main body  100  and a mouthpiece  200  detachably coupled to the first main body  100 , the mouthpiece  200  having an air flow path  201  formed therein. 
     First, the first main body  100  may include a respiration measurement module  110 . The respiration measurement module  110  is configured to measure the pressure of air, and when the first main body  100  and the mouthpiece  200  are coupled to each other, the pressure of air passing through the air flow path  201  may be measured. 
     The first main body  100  may be formed of an operation switch  101  configured to enable a user to control ON/OFF or the like and a connector portion  102  to be connected to an external device (not shown) so that information measured by the respiration measurement module  110  may be analyzed by the external device or stored therein. Here, the connector portion  102  is formed as a connector groove portion as shown in the drawing, and may be applied to various configurations such as a configuration in which a connector pin is detachable from the connector portion  102  or a configuration in which a connecting wire is fixedly coupled thereto. 
     Referring to  FIG.  2   , the respiration measurement module  110  may be configured to sense differential pressure by causing the differential pressure to be generated, and to measure respiration volume or the like based on the sensed differential pressure. 
     To this end, the respiration measurement module  110  may have a first differential pressure generation portion  111  formed to protrude from the side surface thereof facing the air flow path  201 , the first differential pressure generation portion  111  having a predetermined thickness and height. 
     Here, the first differential pressure generation portion  111  is formed to protrude by the predetermined height in the air flow path  201 , thereby obstructing the flow of air through the air flow path  201  and generating differential pressure. 
     The respiration measurement module  110  may have a sensing flow path  112  formed therein to sense the differential pressure generated by the first differential pressure generation portion  111 , and a sensing unit (not shown) may be provided on the sensing flow path  112 . 
     The sensing flow path  112  has an inlet and an outlet formed on opposite sides of the first differential pressure generation portion  111  in the forward-and-backward direction with the first differential pressure generation portion  111  interposed there between, and the sensing unit may be configured to sense a pressure difference at each of the inlet and the outlet. 
     Meanwhile, although not shown, in order to sense the differential pressure, the respiration measurement module  110  may include an atmospheric pressure sensor or a pressure sensor configured to sense a pressure difference between opposite sides of the first differential pressure generation portion  111  instead of the sensing flow path  112  and the sensing unit. 
     The first main body  100  may include a first coupling portion  120  and a second coupling portion  130  detachably coupled to a tube adapter  210 , and the first coupling portion  120  and the second coupling portion  130  will be described in more detail in a third coupling portion  230  and a fourth coupling portion  240  to be described later. 
     The first main body  100  may have a circuit board (not shown) embedded therein and configured to perform operation of the respiration measurement module  110 . 
     The mouthpiece  200  may be formed of the tube adapter  210 , a first tube  270 , and a second tube  280 . 
     The tube adapter  210  has a cylindrical tube shape, and the outer peripheral side surface thereof is detachably coupled to the first main body  100 . Here, the tube adapter  210  may have an insertion hole  213  formed on the outer peripheral side surface thereof, the insertion hole  213  having the respiration measurement module  110  inserted there into when the tube adapter  210  is coupled to the first main body  100 . In this case, the tube adapter  210  may be configured to seal the insertion hole  213  when the respiration measurement module  110  is inserted into the insertion hole  213 . 
     Meanwhile, the insertion hole  213  may be formed in the central portion of the tube adapter  210  in the longitudinal direction, as shown in the drawing, but this is an embodiment and the formation position of the insertion hole  213  may be variously changed. 
     The first tube  270  may be detachably coupled to one side of the tube adapter  210  and the second tube  280  may be detachably coupled to the other side thereof. 
     Referring to  FIG.  3   , the tube adapter  210  may have a first seating surface  211  formed on one inner peripheral surface thereof, wherein the first tube  270  is contact-coupled to the first seating surface  211 , and a second seating surface  212  formed on the other inner peripheral surface thereof, wherein the second tube  280  is contact-coupled to the second seating surface  212 . 
     When the first tube  270  and the second tube  280  are coupled to the opposite sides of the tube adapter  210 , the first seating surface  211  and the second seating surface  212  prevent external air or internal air from flowing into or out of the air flow path  201  inside the mouthpiece  200 , and cause the first tube  270  and the second tube  280  to closely contact the tube adapter  210 , thereby achieving more close coupling there between. 
     The first seating surface  211  and the second seating surface  212  are formed in the circumferential direction of the inner peripheral surface from an end to a predetermined length, as shown in the drawing, and may be formed in the form of a groove having a predetermined depth from the inner peripheral surface. 
     Furthermore, the first seating surface  211  is preferably formed to have the same depth (height) as a thickness of the first tube  270  contact-coupled thereto, and the second seating surface  212  is preferably formed to have the same depth (height) as a thickness of the second tube  280  contact-coupled thereto. 
     Accordingly, when the first tube  270  and the second tube  280  are coupled to the first and second seating surfaces  211  and  212  formed on the opposite sides of the tube adapter  210 , it is possible to prevent generation of unnecessary differential pressure by preventing a step difference from being formed therein. 
     Meanwhile, in the drawing, the tube adapter  210  has the first seating surface  211  formed on one inner peripheral surface thereof and the second seating surface  212  formed on the other inner peripheral surface thereof so that the first tube  270  and the second tube  280  are configured to be respectively inserted into the inner peripheral surfaces of opposite ends of the tube adapter  210 . 
     However, in this embodiment, the first seating surface  211  and the second seating surface  212  may be respectively formed on opposite outer peripheral side surfaces of the tube adapter  210 , and the opposite end portions of the tube adapter  210  may be respectively inserted into and coupled to the inner peripheral surfaces of the first tube  270  and the second tube  280 . 
     The tube adapter  210  may have a second differential pressure generation portion  214  formed to protrude from the inner side surface thereof, the second differential pressure generation portion  214  having a predetermined thickness and height corresponding to the first differential pressure generation portion  111 . 
     The second differential pressure generation portion  214  is formed to protrude by the predetermined height in the air flow path  201  in the same manner as the first differential pressure generation portion  111 , thereby obstructing the flow of air through the air flow path  201  and forming differential pressure. 
     The second differential pressure generation portion  214  may be formed on the inner peripheral surface of the tube adapter  210  in the circumferential direction. 
     In this case, when the first main body  100  and the tube adapter  210  are coupled to each other, the first differential pressure generation portion  111  and the second differential pressure generation portion  214  may be aligned with each other in a line to form an annular orifice on the inner peripheral surface in the tube adapter  210  in the circumferential direction. 
     That is, the first differential pressure generation portion  111  and the second differential pressure generation portion  214  generate differential pressure in the air flow path  201  by forming an annular orifice in the air flow path  201 . Accordingly, the respiration measurement module  110  may measure the flow rate of air passing through the air flow path  201  and measure respiration volume of a user. Here, the principle of measuring the respiration volume from the differential pressure generated by such an orifice will be described in more detail with reference to  FIG.  7    to be described later. 
     The tube adapter  210  may include the third coupling portion  230  and the fourth coupling portion  240 . The third coupling portion  230  and the fourth coupling portion  240  a repositioned to correspond to the first coupling portion  120  and the second coupling portion  130 , respectively. Accordingly, when the tube adapter  210  and the first main body  100  are coupled to each other, the third coupling portion  230  and the fourth coupling portion  240  may be detachably coupled to the first coupling portion  120  and the second coupling portion  130 , respectively. In this case, the third coupling portion  230  and the fourth coupling portion  240  may be respectively formed on one front side of the insertion hole  213  and the other rear side thereof in the longitudinal direction of the tube adapter  210 , but are not limited thereto. 
     Each of the first coupling portion  120 , the second coupling portion  130 , the third coupling portion  230 , and the fourth coupling portion  240  may be formed of a magnet having magnetic force, thereby being attached to or detached from each other. However, this configuration is a preferred embodiment, and various configurations may be applied thereto other than the magnet as long as the respective coupling portions are attachable and detachable to and from each other. 
     Accordingly, the tube adapter  210  and the first main body  100  may be easily coupled to each other through the first coupling portion  120 , the second coupling portion  130 , the third coupling portion  230 , and the fourth the coupling part  240 , and may be easily separated from each other when a user applies external force thereto. 
     Meanwhile, the tube adapter  210  may be formed of a medical plastic material having durability to maintain the shape thereof when the same is coupled to the first main body  100 . 
     The first tube  270  may have a cylindrical tube shape, and one end thereof may be detachably coupled to one side of the tube adapter  210 . When the first tube  270  is coupled to the tube adapter  210 , one side surface of the first tube  270  may be contact-coupled to the first seating surface  211 . 
     The second tube  280  may have a cylindrical tube shape, and one side thereof may be detachably coupled to the other end of the tube adapter  210 . When the second tube  280  is coupled to the tube adapter  210 , one side surface of the second tube  280  may be contact-coupled to the second seating surface  212 . 
     Meanwhile, a user may directly put his or her mouth on the first tube  270  or the second tube  280  and breath there through. Here, the first tube  270  or the second tube  280  is used as a disposable component in consideration of hygiene. In consideration of the configurations of the first tube  270  and the second tube  280 , the first tube  270  and the second tube  280  may be formed of a pulp (paper) material that is easy to manufacture and harmless to the human body. 
     According to the above description, the mouthpiece  200  is formed in such a manner that the tube adapter  210  detachably coupled to the respiration measurement module  110  and the first tube  270  or the second tube  280  configured to allow a user to put his or her mouth thereon may be separated from each other to be detachable from each other, thereby making it possible to easily separate each component and clean the same. Further, the tube adapter  210  is formed of a plastic material, and each of the first tube  270  and the second tube  280  is formed fan inexpensive paper material in a different manner from the tube adapter  210 , thereby making it possible to reduce manufacturing costs and improve economic efficiency. 
       FIGS.  4  and  5    are views showing another embodiment of the mouthpiece  200 . 
     First, referring to  FIG.  4   , a tube adapter  210   a  may include a tube adapter body  261  and an extension portion  262 . 
     The tube adapter body  261  has a cylindrical tube shape, and the outer peripheral side surface thereof is detachably coupled to the first main body  100 . Here, the outer peripheral side surface may have an insertion hole  213  formed to be penetrated there through, the insertion hole  213  having the respiration measurement module  110  inserted there into, when coupled to the first main body  100 . 
     In addition, the tube adapter body  261  has opposite ends to which the first tube  270  and the second tube  280  are detachably coupled, respectively. More specifically, the tube adapter body  261  may have the first seating surface  211  formed on the inner peripheral surface of one end thereof and contact-coupled to the first tube  270 , and a second seating surface  212  formed on the inner peripheral surface of the other end thereof and contact-coupled to the second tube  280 . Here, since the configuration of the tube adapter body  261  including the insertion hole  213 , the first seating surface  211 , and the second seating surface  212  corresponds to the configuration of the tube adapter  210   a  described with reference to  FIG.  1   , a detailed description thereof will be omitted. 
     The extension portion  262  may be formed to extend by a predetermined length in the longitudinal direction (axial direction) from one end side surface (thickness surface) of the tube adapter body  261  and the other end side surface (thickness surface) thereof. 
     Referring to  FIG.  5   , when the first tube  270  and the second tube  280  are coupled to the tube adapter  210   a,  each inner bottom surface of the extension portion  262  may contact a corresponding one of a part of the outer peripheral side surface of the first tube  270  and a part of the outer peripheral side surface of the second tube  280 . 
     The extension portion  262  may guide the first tube  270  and the second tube  280  to be inserted into the tube adapter body  261 , and may more stably support the first tube  270  and the second tube  280  after being coupled thereto. 
     The extension portion  262  may include the third coupling portion  230  and the fourth coupling portion  240 , as shown in the drawing. Since the third coupling portion  230  and the fourth coupling portion  240  have been described above, a detailed description thereof will be omitted. 
     According to the above description, the tube adapter  210   a  in  FIGS.  4  and  5    is formed to include the tube adapter body  261  and the extension portion  262 , and the length of the tube adapter body  261  may be reduced compared to the length of the tube adapter  210  in  FIG.  1   , thereby conserving materials. Further, although the length of the first seating surface  211  and the length of the second seating surface  212  are reduced, the first tube  270  and the second tube  280  may be stably inserted into the tube adapter  210   a  and supported by the same through the extension portion  262 . 
     Next, the mouthpiece  200  may further include a filter unit  300  configured to filter foreign substances that may be introduced or discharged from and to the outside according to respiration of a user. 
     The filter unit  300  may be coupled to at least one of the tube adapters  210  and  210   a,  the first tube  270 , or the second tube  280 . 
       FIGS.  4  and  5    show an embodiment in which the filter unit  300  is configured separately and coupled to the second tube  280 . 
     Referring to the drawings, the filter unit  300  may include a filter body  310  and a filter member  320 . The filter body  310  may have a cylindrical tube shape, and may be configured to communicate with the air flow path  201  after being coupled to the second tube  280  and to be detachably fitted into the other end of the second tube  280 . 
     The filter member  320  is coupled to the inside of the filter body  310  to filter foreign substances. The filter member  320 , as shown in the drawing, is configured in the form of a mesh net, thereby making it possible to filter saliva or the like that is discharged when a user exhales. Here, a mesh net made of general metal, plastic, or the like may be applied to the filter member  320 , but other materials may be applied thereto as long as the above-described purpose is achieved. 
     Meanwhile, the filter unit  300  may be provided in the mouthpiece  200  in a different manner from the configuration shown in  FIGS.  4  and  5   . In this case, the filter unit  300  is not a separate configuration. 
     Referring to  FIG.  6   , a filter unit 300   a  may be provided inside the tube adapter  210 . 
     In this case, the filter unit 300   a  may be located at the rear of the insertion hole  213  in the flow direction so as not to affect sensing sensitivity of the respiration measurement module  110 . 
     The filter unit 300   a  may be formed in a circular shape to correspond to the inner shape of the tube adapter  210 , and the outer peripheral surface thereof may be coupled to the inner peripheral surface of the tube adapter  210 . Here, the filter unit  300   a  may be fixedly coupled to the tube adapter  210  or formed to be integrated therewith. In this manner, various embodiments may be implemented. 
     Meanwhile,  FIG.  6    shows the case in which the filter unit 300   a  is provided in the tube adapter  210 , but it goes without saying that the filter unit  300   a  may be provided in the first tube  270  and the second tube  280  as an embodiment. 
     Hereinafter, a description will be given as to the principle that the respiration measurement module  110  measures respiration volume of a user through the differential pressure generated by the first differential pressure generation portion  111  and the second differential pressure generation portion  214 . 
     First,  FIG.  7    is a view showing a pressure change when an orifice tube is installed inside a general flow path. Referring to the drawing, Equation 1 and Bernoulli&#39;s Equation and Continuity Equation of Equation 2 may be established between an upstream cross section a of the orifice tube and a cross section b thereof where the flow of air becomes narrow. 
     
       
         
           
             
               
                 
                   
                     
                       P 
                       1 
                     
                     + 
                     
                       
                         
                           ρ 
                           1 
                         
                         ⁢ 
                         
                           V 
                           1 
                           2 
                         
                       
                       2 
                     
                   
                   = 
                   
                     
                       P 
                       2 
                     
                     + 
                     
                       
                         
                           ρ 
                           2 
                         
                         ⁢ 
                         
                           V 
                           2 
                           2 
                         
                       
                       2 
                     
                   
                 
               
               
                 
                   Equation 
                   ⁢ 
                       
                   1 
                 
               
             
           
         
       
       
         
           
             
               
                 
                   
                     
                       ρ 
                       1 
                     
                     ⁢ 
                     
                       V 
                       1 
                     
                     ⁢ 
                     
                       A 
                       1 
                     
                   
                   = 
                   
                     
                       ρ 
                       2 
                     
                     ⁢ 
                     
                       V 
                       2 
                     
                     ⁢ 
                     
                       A 
                       2 
                     
                   
                 
               
               
                 
                   Equation 
                   ⁢ 
                       
                   2 
                 
               
             
           
         
       
     
     Here, V 1  and V 2 , P 1  and P 2 , ρ 1  and ρ 2 , A 1  and A 2  respectively represent average flow velocity, pressure, fluid density, and flow cross-sectional area in portions a and b. A relationship between flow rate Q passing through the orifice tube and differential pressure (P 1 −P 2 ) is as shown in Equation 3 through Equation 1 and Equation 2. 
     
       
         
           
             
               
                 
                   
                     
                       
                         Q 
                         = 
                         
                           
                             V 
                             2 
                           
                           ⁢ 
                           
                             A 
                             2 
                           
                         
                       
                     
                   
                   
                     
                       
                         = 
                         
                           
                             A 
                             2 
                           
                           ⁢ 
                           
                             
                               
                                 1 
                                 
                                   
                                     ( 
                                     
                                       1 
                                       - 
                                       
                                         
                                           ( 
                                           
                                             
                                               A 
                                               2 
                                             
                                             / 
                                             
                                               A 
                                               1 
                                             
                                           
                                           ) 
                                         
                                         2 
                                       
                                     
                                     ) 
                                   
                                   
                                     1 
                                     / 
                                     2 
                                   
                                 
                               
                               [ 
                               
                                 
                                   1 
                                   
                                     ρ 
                                     1 
                                   
                                 
                                 ⁢ 
                                 
                                   ( 
                                   
                                     
                                       P 
                                       1 
                                     
                                     - 
                                     
                                       P 
                                       2 
                                     
                                   
                                   ) 
                                 
                               
                               ] 
                             
                             
                               1 
                               / 
                               2 
                             
                           
                         
                       
                     
                   
                 
               
               
                 
                   Equation 
                   ⁢ 
                       
                   3 
                 
               
             
           
         
       
     
     Accordingly, if P 1  and P 2  are known, the flow rate Q may be obtained. Meanwhile, Equations 1 to 3 are known flow rate calculation equations through the orifice, and a detailed description thereof will be omitted. 
     As described above, it may be seen that the flow rate may be measured through the differential pressure measured in the orifice tube. Accordingly, in the present invention, when the first main body  100  and the tube adapter  210  are coupled to each other, the orifice (tube) is formed in the air flow path  201  through the first differential pressure generation portion  111  and the second differential pressure generation portion  214  to generate differential pressure. Thereafter, the differential pressure is measured through the respiration measurement module  110 , thereby making it possible to calculate respiration volume of a user by the above-described measurement principle. 
     Hereinafter, a description will be given of another embodiment in which a first coupling portion 120   a,  a second coupling portion 130   a,  third coupling portions 230   a  and  230   b,  and fourth coupling portions  240   a  and  240   b  are provided in the mouthpiece assembly for there spiration measurement device of the present invention. 
     First, referring to  FIG.  8   , the third coupling portion 230   a  and the fourth coupling portion 240   a  are provided on the outer peripheral side surface of the tube adapter  210 , and may be spaced apart from each other in the circumferential direction of the tube adapter  210  with the insertion hole  213  interposed there between. 
     Referring to  FIG.  9   , each of the third coupling portion 230   a  and the fourth coupling portion 240   a  may include a protrusion portion  251  and a first magnet member  252 . 
     The protrusion portion  251  has a rectangular shape in plan view, and the direction of the long side thereof is arranged in the axial direction of the tube adapter  210 . 
     Here, the protrusion portion  251  is formed to protrude outwards from the outer peripheral surface of the tube adapter  210 , as shown in the drawing, and may serve as a locking protrusion configured to prevent the first main body  100  from shaking when the tube adapter  210  is coupled to the first main body  100 . Accordingly, more stable coupling between the tube adapter  210  and the first main body  100  may be performed. 
     The protrusion portion  251  may include a fitting portion  253  having the first magnet member  252  coupled thereto. 
     The fitting portion  253  may be formed on the upper surface of the protrusion portion  251 , and may be formed in the form of a groove having a predetermined depth from the upper surface of the protrusion portion 251 . 
     The first magnet member  252  may be fitted into the fitting portion  253 , and may be formed to have a thickness corresponding to a shape and a predetermined depth of the fitting portion  253 . 
     The first magnet member  252  has a bottom surface to which a bonding material is applied, wherein the bottom surface is in face-to-face contact with the fitting portion  253 , so that the position thereof is fixed after being inserted into and coupled to the fitting portion  253 , thereby being fixedly coupled to the fitting portion  253 . In this manner, when the first main body  100  is detached from the tube adapter  210 , it is possible to prevent a state in which the first magnet member  252  is separated from the fitting portion  253  while being coupled to a second magnet member  122 . 
       FIG.  10    is a bottom view showing the first coupling portion 120   a  and the second coupling portion 130   a  of the first main body  100  in  FIG.  8   . Referring to the drawing, the first coupling portion 120   a  and the second coupling portion 130   a  are formed so that the third coupling portion 230   a  and the fourth coupling portion 240   a  may be inserted there into and seated thereon, respectively. Each of the first coupling portion 120   a  and the second coupling portion 130   a  may include an insertion groove portion  121  and a second magnet member  122 . 
     First, the insertion groove portion  121  may be located at a position corresponding to each of the first coupling portion 120   a  and the second coupling portion 130   a,  and the protrusion portion  251  may be inserted there into. 
     Here, the insertion groove portion  121  is formed to correspond to the shape of the protrusion portion  251 . Further, the insertion groove portion  121  may be formed so that the bottom surface of the first main body  100  is in contact with the outer peripheral surface of the tube adapter  210 . Accordingly, the protrusion portion  251  may be completely inserted into the insertion groove portion  121  when the insertion groove portion  121  is coupled thereto. 
     The second magnet member  122  is provided in the insertion groove portion  121 , and attractive force thereof is applied to the first magnet member  252  to enable the first main body  100  and the tube adapter  210  to be detached from each other. 
       FIG.  11    is a view showing another embodiment of the third coupling portion 230   b  and the fourth coupling portion 240   b.  Referring to the drawing, each of the third coupling portion 230   b  and the fourth coupling portion 240   b  includes a protrusion portion 251   a  and the first magnet member  252 , and the first magnet member  252  may be inserted into and coupled to the protrusion portion 251   a  in the lateral direction. 
     In this case, the protrusion portion 251   a  may have a fitting portion 253   a  formed on the side surface thereof, and the first magnet member  252  may be inserted into and coupled to the fitting portion 253   a  in the lateral direction. 
     Meanwhile, in this case, the first magnet member  252  may be fitted into the fitting portion 253   a  without a separate bonding material applied thereto. This is because the detachment direction of the first main body  100  and the coupling direction of the first magnet member  252  are different from each other, and the upper surface of the protrusion portion 251   b  is shielded. Accordingly, when the first main body  100  is detached from the tube adapter  210 , it is possible to prevent a state in which the first magnet member  252  is separated from the fitting portion  253   a  while being coupled to the second magnet member  122 . 
     Hereinafter, another embodiment of the mouthpiece  200  will be described. 
     Referring to  FIG.  12   , the mouthpiece  200  may further include a rotation prevention portion  400  capable of preventing rotation of the first tube  270  and the second tube  280  in the state in which the first tube  270  or the second tube  280  is fitted into and coupled to the tube adapter  210 . 
     The rotation prevention portion  400  may include a rotation prevention groove  410  and a rotation prevention protrusion  420 . 
     The rotation prevention groove  410  may be formed to have a predetermined length in the insertion direction from one end of the first tube  270 . The rotation prevention groove  410  may not only prevent rotation of the second tube  270  after the first tube  270  is coupled to the tube adapter  210 , but also guide the insertion of the first tube  270  into the tube adapter  210 , thereby making it possible to perform easier and more stable coupling there between. Here, the rotation prevention groove  410  may limit the insertion depth through the formed length thereof. Accordingly, it is possible to prevent the first tube  270  from being excessively inserted into the tube adapter  210 . 
     The rotation prevention protrusion  420  is formed on the inner peripheral side surface of one end of the tube adapter  210 , and is fitted into the rotation prevention groove  410  when the first tube  270  is coupled to the tube adapter  210 . 
     The rotation prevention protrusion  420  may have various shapes such as a cylindrical shape or a square box shape, and the rotation prevention groove  410  may be formed in a shape corresponding to the shape of the rotation prevention protrusion  420  so that the outer surface of the rotation prevention protrusion  420  is in close contact with the rotation prevention groove  410  when the rotation prevention protrusion  420  is inserted into the rotation prevention groove  410  and seated therein. 
       FIG.  13    is a view showing another embodiment of the mouthpiece of the present invention. 
     Referring to the drawing, a tube adapter  210   b  may have a fitting groove portion  2111  formed on the first seating surface  211 . 
     The fitting groove portion  2111  is formed at a stepped portion of the first seating surface  211 , and when the first tube  270  is seated on the first seating surface  211  and contact-coupled thereto, the insertion end of the first tube  270  is fitted into the fitting groove portion  2111 . 
     Since the first tube  270  is made of a thin paper material, the fitting groove portion  2111  prevents lifting or crumpling that may occur when the first tube  270  is inserted into the tube adapter  210   b,  thereby making it possible not only to reduce flow resistance due to such lifting or crumpling when a user breathes in and out, but also to prevent deterioration in sensing sensitivity. Meanwhile, it goes without saying that the fitting groove portion  2111  may be formed not only on the first seating surface  211  but also on the second seating surface  212 . 
     Furthermore, although not shown, the mouthpiece  200  may include a respiration pressure adjustment unit provided in the first tube  270  or the second tube  280  and configured to adjust respiration pressure of a user. The respiration pressure adjustment unit adjusts the flow passage and cross-sectional area of the air flow path  201  during respiration to adjust the pressure of respiration flowing into the air flow path  201 , thereby providing respiration pressure suitable for the user&#39;s health condition during aerobic exercise. Accordingly, it is possible to increase the effects of aerobic exercises of individual users. 
     Although the present invention has been described with reference to the embodiments shown in the drawings for illustrative purposes, those skilled in the art will appreciate that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention should be determined by the technical spirit of the appended claims. 
     Industrial Applicability 
     As is apparent from the above description, the present invention may be applied to a respiration measurement device.