Patent ID: 11931199
Assignee: nan
Field: Other consumer goods (Other fields)
Classification: CPC A  G | IPC A  B  F  G

Claim 3:
4. A phonendoscope [2.B, 2.C];
the phonendoscope comprising the acoustic nozzle of claim 1,
wherein the inner canal is configured as a two-stage convergent-divergent tunnel comprising three sequentially joint fragments as follows:
A first convergent-divergent fragment;
A divergent-convergent cavity; and
A second convergent-divergent fragment;

wherein:
said open sound-inlet having the sound-inlet cross-sectional area, indicated by AIN, is an open sound-inlet of the first convergent-divergent fragment,
said open sound-outlet having the sound-inlet cross-sectional area, indicated by AOU, is an open sound-outlet of the second convergent-divergent fragment, and
the divergent-convergent cavity has a local maximal cross-sectional area, indicated by ACA;
the cross-sectional area profile smooth function A(x) is composed of sequentially concatenated cross-sectional area profile functions A1(x), ACA(x), and A2(x), wherein:
A1(x) is cross-sectional area profile function of the first convergent-divergent fragment, which provides for the enhanced de Laval retarding-effect resulting in deceleration of the fluid tiny portion,
A2(x) is cross-sectional area profile function of the second convergent-divergent fragment, which provides for the enhanced de Laval jet-effect resulting in acceleration of the fluid tiny portion, and
the cross-sectional area profile functions A1(x) and A2(x) are given by the equations expressed as:, 
  
   {
   
    
     
      
       
        
         
          A
          1
         
         (
         x
         )
        
        =
        
         
          
           A
           
            TH
            ⁢
            1
           
          
          
           
            M
            1
           
           (
           x
           )
          
         
         ⁢
         
          
           (
           
            
             γ
             -
             1
            
            γ
           
           )
          
          
           1
           2
          
         
         ⁢
         
          
           (
           
            
             2
             +
             
              
               γ
               ⁡
               (
               
                
                 M
                 1
                
                (
                x
                )
               
               )
              
              2
             
            
            
             γ
             +
             1
            
           
           )
          
          
           
            γ
            +
            1
           
           
            2
            ⁢
            
             (
             
              γ
              -
              1
             
             )
            
           
          
         
        
       
       ,
      
     
     
      
       
        x
        
         a
         ,
         1
        
       
       <
       x
       <
       
        x
        
         b
         ,
         1
        
       
      
     
    
    
     
      
       
        
         
          A
          2
         
         (
         x
         )
        
        =
        
         
          
           A
           
            TH
            ⁢
            2
           
          
          
           
            M
            2
           
           (
           x
           )
          
         
         ⁢
         
          
           (
           
            
             γ
             -
             1
            
            γ
           
           )
          
          
           1
           2
          
         
         ⁢
         
          
           (
           
            
             2
             +
             
              
               γ
               ⁡
               (
               
                
                 M
                 2
                
                (
                x
                )
               
               )
              
              2
             
            
            
             γ
             +
             1
            
           
           )
          
          
           
            γ
            +
            1
           
           
            2
            ⁢
            
             (
             
              γ
              -
              1
             
             )
            
           
          
         
        
       
       ,
      
     
     
      
       
        x
        
         a
         ,
         2
        
       
       <
       x
       <
       
        x
        
         b
         ,
         2
        
       
      
     
    
   
  
 

where:
xa,1 and xb,1 are x-coordinates of the open sound-inlet and open sound-outlet, correspondingly, of the first convergent-divergent fragment,
xa,2 and xb,2 are x-coordinates of the open sound-inlet and open sound-outlet, correspondingly, of the second convergent-divergent fragment,
M1(x) is a monotonically-decreasing gradually-smooth function of x,
M2(x) is a monotonically-increasing gradually-smooth function of x, and
ATH1 and ATH2 are local minimal cross-sectional areas of narrow throats of the first and second convergent-divergent fragments, correspondingly;
ACA(x) is cross-sectional area profile function of the divergent-convergent cavity defined between xb,1 and xa,2 such that providing for the enhanced Venturi effect as a gradually-smooth function MCA(x) of x, representing an M-velocity profile of the tiny portion of the fluid moving in the divergent-convergent cavity between the first and second narrow throats, remains lower than the specific M-velocity M*=√{square root over ((γ−1)/γ)};
M1(x), MCA(x), and M2(x) are sequentially-concatenated to form a gradually-smooth function M(x) of x, representing an M-velocity profile of the fluid tiny portion moving within and through the two-stage convergent-divergent nozzle's through-hole tunnel-waveguide; and
interrelations between the cross-sectional areas AIN, ATH1, ACA, ATH2, and AOU satisfying conditions as follows:, A
        IN
       
       
        A
        
         TH
         ⁢
         1
        
       
      
      ≥
      
       
        
         (
         
          
           γ
           -
           1
          
          γ
         
         )
        
        ⁢
        
         
          (
          
           
            2
            +
            γ
           
           
            γ
            +
            1
           
          
          )
         
         
          
           γ
           +
           1
          
          
           (
           
            γ
            -
            1
           
           )
          
         
        
       
      
     
     ,
    
   
   
    
     (
     f
     )
    
   
  
 

 
  
   
    
     
      
       A
       CA
      
      >
      
       A
       
        TH
        ⁢
        1
       
      
     
     ,
    
   
   
    
     (
     g
     )
    
   
  
 

 
  
   
    
     
      
       A
       CA
      
      >
      
       A
       
        TH
        ⁢
        2
       
      
     
     ,
    
   
   
    
     (
     h
     )
    
   
  
 

 
  
   
    
     
      
       A
       
        TH
        ⁢
        1
       
      
      ≥
      
       A
       
        TH
        ⁢
        2
       
      
     
     ,
     and
    
   
   
    
     (
     i
     )
    
   
  
 

 
  
   
    
     
      
       
        A
        OU
       
       
        A
        
         TH
         ⁢
         2
        
       
      
      >
      
       
        
         (
         
          
           γ
           -
           1
          
          γ
         
         )
        
        ⁢
        
         
          (
          
           
            2
            +
            γ
           
           
            γ
            +
            1
           
          
          )
         
         
          
           γ
           +
           1
          
          
           (
           
            γ
            -
            1
           
           )
          
         
        
       
      
     
     ;
    
   
   
    
     (
     j
     )
    
   
  
 

thereby providing for that, a portion of the propagating sound, entering the open sound-inlet, propagating through the two-stage convergent-divergent tunnel, and becoming launched from the open sound-outlet, becomes characterized by an amplified loudness.