US2374671A - Turbine - Google Patents

Description

E. DUPONT May I, 1945.

TURBINE Filed Oct. 16. 1941 4 Shets-Sheet 1 May 1, 1945.

a DUPONT TURBINE Filed 001:. 16, 1941' 4 Sheets-Sheet 3 Patented May 1, 1945 TURBINE Emile Dupont, Antibes, France; vested in the Alien Property Custodian Application October 16, 1941, Serial No. 415,306 r In Switzerland June 24, 1941 2 Claims.-

This invention relates to a machine used for converting mechanicaliorce into a pressure or conversely, where the manometric height measuring the pressure used or produced by a single wheel is distributed over a plurality of concentric blade rims suitably spaced and arranged on one of the faces of the rotor, and over a plurality of concentric blade rimsarranged on one face of the stator and inserted into the ring spaces between the blade rims of the rotor, the flow of the fluid being a centrifugal flow when the machine converts mechanical force into a pressure (compression and fluid pumps) and an inward radial flow when the machine converts pressure into mechanical force (gas turbine, steam and water turbines).

In the known machines of this kind the axial balancing is efiected by means of a chamber between the face of the rotor without blades and a wall of the stator, and in which chamber the pressure is uniform and generally equal to the high pressure of the fluid. This is obtained by means of a passage provided in the rotor and insuring a communication between the said balancing chamber and the high presure.

Thus, one of the faces of the rotor is submitted, for instance, to a uniform pressure, while the other face is submitted to decreasing pres.- sures in front of each of the fixed and movable blade rims according to the working of the machine as a compressor.

Accordingly, in these known machines the resulting pressure, that is to say the difference between the pressures acting on the two faces of the rotor, varies according to the distance of the point under consideration with respect to the point where ambient atmospheric pressure exists.

The rotor is thus submitted in each of its points to resulting axial pressures the value of which varies and whichfor this reason do not produce a good balancing effect. In every case, the balancing effect is perfect only for a predetermined particular value of the highest fluid pressure and the least variation of this pressure produces an axial thrust.

The present invention has for an object to avoid these drawbacks and to obtain a good axial balancing of the rotor in all the points of its surface.

On the other hand, machines with concentric arate the said jet from the convex face of the blade, which causes eddies which are prejudicial to efficiency.

Another object of the present invention is to avoid this drawback and to improve the known machines so as to avoid any separation of the fluid jet from the convex face of the blade.

The improved machine which accomplishes the above mentioned objects possesses the features set forth in the following description and more V particularly in the appended claims.

Machines made according to the invention are shown by way of example in the appended drawings in which: 7

Figure l is an axial sectional view of the machine. A

Figure 2 is a partial axial sectional view' of the said machine.

Figure 3 is a diagram showing the axial pressures in-the machine according to the invention.

Figure 4 is on a larger scale a cross-sectional viewthrough the blades with the parallelograms of velocities.

Figure 5 is a partial axial cross-sectional view of modified form of machine according to the invention.

Figure 6 shows the lay-out of the blades of a machine according to the invention.

The machine shown in Figures 1 to 4 has a driving shaft I. A rotating wheel 2 is keyed on the driving shaft I; the wheel 2 is profiled in its middle part according to a cone 3 the profile of which corresponds to that of the gaseous je'. flow path on the intake side of the apparatus.

The rotating wheel 2 carries on one face 2 blade rims 4 4 4 4 the movable blades; the

profile of the said blades 4 4 4 4 (Figure 4) varies from one rim to the other and according to the characteristics of the apparatus (velocity, delivery) but they are always such that two successive blades of one and the same rim form a curvilinear nozzlea The face 2 of the wheel which is not provided .with blades carries'circular ribs 5 5 5 5 '5 5 5" adapted for forming the annular chambers C C and C The stator is provided with a slightly conical bracket 6; this bracket carries fixed blade rims 1 1 I 1 l which are inserted between the movable blade rims 4 to 4 the fixed blade rim 1 being arranged externally with respect to the movable blade rim 4 Like the movable blades, the fixed blades are so formed that two successive blades of one and the same rim form a curvilinear nozzle.

The stator is also provided with a bracket 8 which carries on one of its faces circular ribs 9 9, 9 9 9 9 9" forming with the circular ribs 5 to 5" of the rotating wheel 2, chambers I0 I0 I0 I0 I0 I0, I 0", In, which are connected together by conduits of small section H II, II, II. II, II. Aconduit I2 is provided between the fixed blade rim 1 and the movable bladerim 4 the said conduit connects the chamber I with the face2 of the wheel 2.

The conduits II and I2 are formed by the necessary clearances between the fixed and movable parts.

Counterpressure chambers 1 1 1 and. I are provided between the fixed blade rims l 1 1 and I and the face 2 of the wheel 2.

Passages I1 I1 I1 11* are provided in the 'wheel 2 and connect chambers 1 1 1, 1 and chambers I0 I0 and It.

Counter-pressure chambers 35 35 35 35" are provided between the cover ring 3B 3B 36?, 38" of each movable blade rim and the bracket 6 of the stator.

The fluid is admitted through a conduit l3 provided in the stator and opening into an admission manifold it; the fluid leaving the blades is delivered into an outlet manifold I5 and flows out through openings it which are provided in this manifold lb.

The above described machine works as a compressor in the following manner:

The rotor rotates in the direction of the arrow 1 (Figure 4); a movable blade rim 8 and the fixed blade rims l and l which are directly on both sides of the former will now be considered. The fixed blades of the rim 1 which are so inclined as to insure the correct-inlet of the fluid into the movable blades form a distributor. .The fixed blades of the rim 1 act as a diffusor for the movable blade rim 4 and as a distributor for the movable blade rim t 1 Thus, each movable blade rim 4 to 4 produces an independent compression as well as each fixed blade rim 7 to 1 so that successive compression stages are formed seriatim. 1

The gaseous fluid which is thus drawn in through the axial conduit is progressively com- (30S (11*- UoVu 005 do) where P is'the weight of fluid treated per second,

9 the acceleration of the gravity,

U1 the driving velocity on the periphery of the movable blade rim,

.Vi the absolute velocity of the fluid leaving the movable blade rim,

al the angle formed by both these velocities,

U0 the driving velocity at the inlet to the movable blade rim,

Vo the absolute velocity of the fluid. at this inlet,

and I do the angle formed by these two velocities.

The profile of the movable blades is selected so as to give to the angle a0 a, value of more than 90; accordingly the term UoVo cos so has a'positive value and is added to the term Ulvl cos G1 in the above given formula, thus giving the power W.

The slight inclination of the movable blade' manner: the passages I1 I1 I1 I14 connect the annular chambers I0 Hi I0 Ill with the corresponding fixed blade rims T i 1 and i of the face 2 of the rotor and thus produce in the said chambers pressures which are equa1 to the pressures existing in the said fixed blade rims and acting on the face 2 of the rotor. At these points of the rotor the pressure is thus the same on the face 2 and onthe face 2 thus producing the axial balancing effect.

On the other hand, the passages I i connect the chambers W to it together so that in the chamber N1 for instance, a pressure is established which is intermediate to the pressures existing in the chambers l0 and I0 between which the said chamber is inserted. This intermediate pressure is the same as the pressure exerted by the chamber 35 on the cover ring 36 of the movable blade rim 4 This pressure is intermediate between the pressures existing in the fixed blade rims I and 1 between which the movable blade rims 4 are inserted; in a like manner the pressure in the chambers 35 35 35 corresponding to the movable blade ribs 4 4 and 4 corresponds to an equivalent pressure in the chambers I0 I0 I0 opposite to the said movable blade rims.

Thus the pressures are equal in all points on each face of the rotor so that the axial balancing is attained in a perfect manner.

This regular distribution of the balancing effect is clearly shown by the diagram of Figure 3; to each pressure P1 Pn acting on the face 2 of the rotor whichis provided with movable blades corresponds an equal counter-pressure of contrary direction P1 Pn acting on the opposite face 2 of the said rotor; thus an axial balancing effect is obtained in each point of the surface of the rotor.

Numerous changes can be made in the machine shown in Figures 1 to 3 without departing from the spirit and scope of the invention.

Figure 5 more particularly shows a machine according to another modification of the invention. The rotor 2 of this machine is provided on its face 2 with annular chambers I8 l8 I811 acting as balancing chambers. These annular balancing chambers are connected together by passages I9 I9, the whole of the chambers I8 and of the passages I9 forming a labyrinth in which the fluid velocity acquired in one passage I9 is reduced to zero in the following chamber l8.

-0n the other hand, in the cover rings 21 21 of the movable blade rims, hollows are provided which form annular balancing chambers 22 22 22 and 24 24 24 with the wall 25 of the stator, the chambers 24' being connected together by the passages 23 23 23 and the chambers 22 being connected together by the passages 25 25 25 The cover rings '28 of the fixed blade rims are also provided with cavities forming with the wall 2' of the rotor annular balancing chambers 20', 20 connected together by passages 2P, 2|, 2|.

Passages 26 2G, vided in the wheel 2 and connect both faces of the wheel together in the place of the balancing chambers 20 and I8, 20 and I8. Certain of these passages 28 are always arranged between the centre of the rotor and the-first movable blade rim in order to connect the centre of the rotor with the intake side of the machine, and must have a sufflcient cross-sectional area for leading the fluid leakage from the face 2 towards the face 2 In the annular chambers, for instance 20 20", 20 a flow of fluid will establish itself through the passages Il 21", 2| so that the pressure existing in these chambers will be the same as the pressure existing in the blade rim 1. In short, this device establishes a pressure in the space between the cover ring of the blades and the stator in the case of a movable blade rim, or between the blade cover ring and the rotor in the case of a fixed blade rim, which pressure is equal, on the one hand, to the pressure existing in the blade rim under consideration and, on the other hand, to the pressure existing in the corresponding chambers of the face 2% of the rotor, thus producing an axial balancing effect in all the points of the rotor.

This machine ofiers variousadvantages and more particularly the following ones:

. in any number are pro- (a) A perfect balancing effect is obtained if the member of the chambers and the dimensions of the latter are the same for each face of the wheel;

(b) The tightness between two successive blade rims is increased, so that leakage is reduced and the efficiency increased. I

For working as a compressor the machine of the invention avoids the drawbacks of the known blade rims by providing a particular form of blade rims (Figure 6).

The blades of these fixed and movable blade rims have an increased thickness 31 from the region of their bend up to their extremities; accordingly, the fluid Jet remains always in contact with the convex surface 38 of the blade and thus the above mentioned separating effect due to the centrifugal'force is avoided.

The blades are also provided on their outlet faces with a cylindrical surface 39 which is so formed that the fluid jet 40 leaving the front blade rim leaves a partial vacuum zone 4| in the following blade rim.

The said blade rims offer the following advantages:

(a) The eiliciency of the curvilinear nozzle front of the rear edge of the fixed blade (position shown in Figure 6) Then, during the time which the movable blade requires for travelling along the segment e, its hollow face receives no fluid. Thus, the pressure drops along this hollow face due to the inertia of the fluid which it contained and which possessed a certain velocity, as well as due to the friction of the jet flowwhich flows along the convex face of the preceding blade.

When the hollow face of the movable blade comes in front of the point B (front edge of the fixed blade) the pressure existing along this hollow face is nearer to that which exists in B.

The tendency of the fluid jet to flow back which periodically occurs in blade rims made according to the methods heretofore employed, each time when a movable blade passes in front of a fixed blade, is reduced to a low value or even to zero in the case of my invention. Eddies are thus less violent and the internal eiflciency is therefore improved.

My invention covers this particular form of structure of the blades irrespective of the kind of turbine or compressor in which the said blades are used.

I claim:

1. In a machine for converting the pressure of a fluid into mechanical force or conversely: a rotor formed of a disc carrying on one of its faces concentric suitably spaced blade rims, a stator also carrying concentric blade rims inserted into the annular spaces between the blade rims of the said rotor, cover rings for the fixed and movable blade rims, means for radially conducting the fluidinto the concentric blade rims of the said stator and rotor, annular'chambers provided on the face of the rotor which is not provided with blade rims, each annular chamber being ar-' ranged in front of a blade ,rim, annular balancing chambers provided between the cover rings of the fixed blade rims and the rotor, onthe one hand, and the movable blade rims and the stator on the other hand, the said annular balancing chambers simultaneously insuring tightness beformed of two successive blades of one and the same blade. rim is increased since the fluid let flow path is not separated from the convex surface 38, which avoids the formation of eddies in the said J6 (-b) The action of the centrifugal force ina curvilinear blade rim has for its effect that at A (Figure 6) the pressure is considerably higher than at B. v

Thus as the-hollow face of a movableiblade is moving in the direction of the arrow and receives fluid of a higher pressure, their the edge of this movable blade is ata given instant positioned in tween the successive blade rims and the balancing of the rotor and of the cover rings of the fixed and movable blade rims and passages for conducting the fluid to the annular chambers.

2. In a machine forconverting the pressure of a fluid into mechanical force or conversely: a rotor formed of a disc carrying on one of its faces concentric suitably spaced blade rims, a stator also carrying concentric blade rims inserted into the annular spaces between the blade rims of the said rotor, the successive fixed or movable blades leaving between themselves spaces'in form of nozzles, the profile of the movable blades being such that the direction of movement of the fluid at the inlet is reversed with respect to the direction of the movement of the blades, means for radially leading the fluid into the concentric blade provided with blade rims, each annular chamber being arranged in front of a blade rim in order to insure an axial balancing effect in every point of the surface of the rotor and passages for conducting the fluid to the annular chambers.

Elm-E DUPON'I T.

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