Impulse turbine, particularly of the reversible type

Abstract

An impulse turbine, particularly of the reversible type, comprises at least a runner fast on a shaft in order to be rotatable about an axis of rotation. Each runner is provided with at least a hollow working member adapted to receive a fluid fed according to a direction substantially transverse with respect to said axis of rotation, from an inlet portion to a discharge portion of the hollow working member, so that thrust forces are generated whose resultant tends to drive the runner into rotation as a result of the passage of the fluid in the hollow working member. The distance between the straight line of action of the resultant of the thrust forces on each hollow working member and the axis of rotation of the runner is smaller than the distance between the inlet portion of each hollow working member and the axis of rotation of the runner.

1 . An impulse turbine, particularly of the reversible type, comprising at least a runner fast on a shaft so as to be rotatable about an axis of rotation, each runner being provided with at least a hollow working member adapted to receive a fluid fed according to a direction substantially transverse to said axis of rotation, from an inlet portion of the hollow working member to a discharge portion thereof, so that as a result of the passage of the fluid in the hollow working member thrust forces are generated whose resultant tends to drive said runner into rotation, wherein the distance between the straight line of action of the resultant of the thrust forces on each hollow working member and the axis of rotation of the runner, is smaller than the distance between the inlet portion of each hollow working member and the axis of rotation of the runner.  
   
   
       2 . An impulse turbine according to  claim 1 , wherein the inlet portion of each working member of the runner opens towards a direction tangential to the runner.  
   
   
       3 . An impulse turbine according to  claim 2 , wherein the discharge portion of each working member of the runner is wider than the relative inlet portion.  
   
   
       4 . An impulse turbine according to  claim 3 , wherein each working member of the runner is provided with an arched bottom surface intended to allow said fluid to flow, for example having the shape of a portion of an arc of circle or of an ellipse, which extends by an angle a little smaller than 180°, as about 170°.  
   
   
       5 . An impulse turbine according to  claim 1 , wherein each working member of the runner is such that the point at which the resultant of the thrust forces applied to it as a result of the sliding of the fluid acts, is located between the inlet portion of the working member and a plane of reference which passes along the axis of rotation of the runner and is perpendicular to a segment joining the inlet portion and the discharge portion of the same working member, so that the runner tends to rotate in such a way that the inlet portion of each working member moves in agreement with the fluid fed to it.  
   
   
       6 . An impulse turbine according to  claim 1 , wherein each working member of the runner is such that the point at which the resultant of the thrust forces applied to it as a result of the sliding of the fluid acts, is located between the discharge portion of the working member and a plane of reference which passes along the axis of rotation of the runner and is perpendicular to a segment joining the inlet portion and the discharge portion of same working member, so that the runner tends to rotate in such a way that the inlet portion of each working member moves towards the fluid fed to it.  
   
   
       7 . An impulse turbine according to  claim 1 , wherein each working member of the runner is constituted by a blade with an open concave section, provided with an arched bottom surface.  
   
   
       8 . An impulse turbine according to  claim 7 , wherein the runner comprises at least a pair of opposed blades, the bottom surface of each blade having a centre line which is located on a plane inclined of about 60° with respect to the axis of rotation of the runner.  
   
   
       9 . An Impulse turbine according to  claim 7 , wherein each blade of the runner is fed with said fluid by means of a distributor unit adapted to cause the delivery of the fluid in a direction mainly tangential with respect to a circular outflow opening thereof, the runner being arranged coaxially with said outflow opening in such a way that the inlet portion of its blades are arranged within said outflow opening.  
   
   
       10 . An impulse turbine according to  claim 9 , wherein the distributor unit comprises a chamber for the circulation of the fluid, which is delimited by a wall arranged according to a generally spiral configuration, to which the fluid is fed through a tangential feeding duct.  
   
   
       11 . An impulse turbine according to  claim 10 , wherein the distributor unit comprises means for adjusting the flow rate of the fluid fed to said circulation chamber, which include a member movable with respect to the circulation chamber and adapted to take a plurality of positions in which such a member interferes in a different measure with the flow of the fluid coming from the tangential feeding duct.  
   
   
       12 . An impulse turbine according to  claim 1 , wherein each working member of the runner is defined by a tubular duct formed within the thickness of a bell-shaped body, each tubular duct being wound in a substantially helical manner with respect to the axis of rotation of the runner.  
   
   
       13 . An impulse turbine according to  claim 12 , wherein each tubular duct of the runner is fed from a delivery pipe coaxial with the axis of rotation of the runner.  
   
   
       14 . An impulse turbine according to  claim 13 , wherein the runner is associated with a shaft arranged coaxially inside said delivery pipe, such a shaft extending outside the delivery pipe at an elbow portion thereof.  
   
   
       15 . An impulse turbine according to  claim 13 , wherein the body of the runner includes first and second half-shells coupled to each other, a series of open channels being formed in the first half-shell and the second half-shell constituting a cover adapted to close said channels in its condition coupled with the first half-shell, so as to delimit a series of tubular ducts.