Method and device for reducing pressure fluctuations in an induction pipe of a water turbine or water pump or water-pump turbine

Abstract

The invention relates to a turbine or pump or pump turbine, comprising a rotor which has a plurality of rotating blades and a hub, a housing which has a distributor for regulating the currents flowing into the rotor, and an induction pipe for guiding the water flowing out of the rotor, comprising an inlet diffusor. The inventive turbine or pump or pump turbine is characterized by the following characteristics; an elongate displacement body is arranged in the induction pipe and the upstream end of the displacement body is arranged in the region of the hub of the rotor.

1 - 7 . (canceled)  
   
   
       8 . A turbine for pumping a medium comprising: 
 a runner having one or more rotor blades and a hub;    a housing having a distributor that regulates flow of the medium into the runner;    a draft tube that guides the medium flowing out from the runner and having an inlet diffuser; and    a displacement unit in the draft tube and having an upstream end in proximity to the hub, wherein the displacement unit has a variable width.    
   
   
       9 . The turbine of  claim 8 , wherein the width of the displacement unit increases in the direction of flow of the medium.  
   
   
       10 . The turbine of  claim 8 , wherein between the hub and the upstream end of the displacement unit is a distance that is between 0.5 mm and 50 mm.  
   
   
       11 . The turbine of  claim 8 , wherein the displacement unit is supported by rods connected to the draft tube.  
   
   
       12 . The turbine of  claim 8 , wherein the displacement unit is supported on the hub of the runner.  
   
   
       13 . The turbine of  claim 8 , wherein the displacement unit is integrally formed with the hub of the runner and rotates with the hub.  
   
   
       14 . The turbine of  claim 8 , wherein the draft tube runs along a substantially straight line.  
   
   
       15 . The turbine of  claim 8 , wherein the draft tube is curved.  
   
   
       16 . The turbine of  claim 8 , wherein the displacement unit extends substantially longitudinally in the draft tube.  
   
   
       17 . The turbine of  claim 8 , wherein the width of the displacement unit is tapered in the direction of flow of the medium.  
   
   
       18 . The turbine of  claim 8 , wherein the medium being pumped is water.  
   
   
       19 . A method of reducing pressure fluctuations in a turbine that pumps a medium, the method comprising: 
 regulating flow of the medium into a runner via a distributor in a turbine housing;    guiding the medium flowing out from the runner via a draft tube; and    reducing swirling of the medium by varying an inner cross-sectional area of the draft tube in proximity to the runner.    
   
   
       20 . The method of  claim 19 , wherein the inner cross-sectional area of the draft tube is varied by positioning a displacement unit of varying width in the draft tube.  
   
   
       21 . The method of  claim 20 , wherein the width of the displacement unit increases in the direction of flow of the medium.  
   
   
       22 . The method of  claim 21 , wherein between a hub of the runner and an upstream end of the displacement unit is a distance that is between 0.5 mm and 50 mm.  
   
   
       23 . The method of  claim 20 , wherein the displacement unit is supported by rods connected to the draft tube.  
   
   
       24 . The method of  claim 20 , wherein the displacement unit is integrally formed with the hub of the runner and rotates with the hub.  
   
   
       25 . The method of  claim 20 , wherein the draft tube runs along a substantially straight line.  
   
   
       26 . The method of  claim 20 , wherein the draft tube is curved.  
   
   
       27 . The method of  claim 19 , wherein the medium being pumped is water.