US1024391A - Nozzle of axial-flow turbines. - Google Patents

Description

H. BOLTSHAUSER. NOZZLE FOR AXIAL FLOW TURBINES. APPLICATION FILED JAN. 26, 1911.

1,024,39 1 Patented Apr. 23, 1912.

fl it COLUMBIA PLANOGRAPH co.,WASH1NOTON, D c.

'iINITED STATES PATENT @FFIQE.

HEINRICH BOLTSHAUSER, OF ZURICH, SWITZERLAND, ASSIGNOR TO AKTIENG-ESELL- SGI-IAF'I DER MASCHINENFABRIKEN ESCHER WYSS & CIR, 0F ZURICH, SWITZER- LAND.

NOZZLE OF AXIAL-FLOW TURBINES.

To all whom it may concern:

Be it known that I, HEINRICH BOLTS- HAUSER, engineer, citizen of Switzerland, residing at 72 Vinterturerstrasse, Zurich, IV, Switzerland, have invented new and useful Improvements in or Connected with the Nozzles of Axial-Flow Turbines and Turbo- Compressors, of which the following is a specification.

This invention relates to axial-flow turbines driven by steam, gas or water and to axial-flow turbo-compressors, and consists in an improved arrangement of the nozzles for the same.

The object of the invention is to construct the annularly arranged nozzles formed by blades cast in or inserted in any convenient way into cylindrical rings in such a manner, that when they are tooled or finished in order to obtain as smooth a surface as possible, for instance by means of a drift, the jets of motive fluid so strike the rotor that the vanes of the rotor at their inlet ends require only the least possible increase of width over that of the nozzles at their outlet ends.

The nature of the invention will be best explained with reference to the drawing appended hereunto, which relates to a steam turbine.

In said drawings, Figure 1 shows an axial projection of several of the outlet openings of the nozzle-ring and nozzles, Fig. 2 shows a sectional View looking in axial direction through the nozzlering and nozzles, and the bucket-s of the rotor which lie behind said nozzles, Fig. 8 shows diagrammatically the positions of the figures of intersection of the ets of steam from the nozzles with the plane CD of Fig. 2. Fig. 4: shows the figures of intersection illustrated in Fig. 3 turned sufiiciently in the direction of rotation of the rotor, so that the upper and lower bounding lines thereof lie wholly or nearly all in concentric circles, and Fig. 5 shows an axial projection of the outlet openings of the nozzle-ring, whereby said openings are turned suificiently, so that the issuing jets of steam intersect the plane CD of Fig.2 according to the figures of intersection of Fig. 4:.

a, b, 0, cl and e, f, g, h are two adjacent nozzles I and II inclosed by two radial blades and the segment-a1 arcs (1 cl, Z) c, and e h, f g, respectively. The central threads of Specification of Letters Patent.

Application filed January 26, 1911.

Patented Apr. 23, 1912. Serial No. 604,787.

the jets issuing from the nozzles, I and II at z and la form equal angles with the plane of the nozzle ring. But as they are set over by one division on the circular are passing through i and is Fig. 1, these central threads of the jets lie skewed relatively to one another in space and on the surface of a hyperboloid. Now if the adjacent nozzles I and II were so cast that they could be finished by means of a drift and this finishing work were actually carried out, the generatrixes of the nozzle I terminating as the corner points a, Z), c, and 03 would be parallel to the central thread of the jet issuing at 2' and the generatrixes of the nozzle II terminating at the corner points 6, f, g, it, would all be parallel to the central thread issuing at 70. Through this manner of constructing the nozzles and finishing them by means of a drift, the generatrixes terminating at the points a and e and likewise those terminating at d and 72, would each lie on a hyperboloidical surface, but these hyperboloids would be different from each other. Foras the generatrix terminating at (Z is parallel to the central thread i Z, and that terminating at 6 parallel to the thread 7c-7c and as the central thread 2 -2, and Z27c of the jets are in a skewed position to each other, the same will be the case with the immediately adjacent threads of the jet passing through (Z and 6. Now if according to Fig. 2 the plane of entry C D of the rotor is at a distance 25, from the plane A B of the outlets of the nozzles, it will be easily understood that the cont-inuations of the nozzle generatrixes as defined above, passing through the points d and e will encounter the plane C D, at two points, which lie no longer in a circle, but at two quite different distances from the axis of the wheel.. The same is the case with the generatrixes which pass through the plane A B of the nozzle ring at the points a and h, and so on. The intersections of the steam jets issuing from the channels I and II, with the plane C D will have the positions shown in Fig. 3, in which the points a b and so on correspond to the threads of jet passing in the plane A B of the nozzle ring through the points a, b and so on. If these jets are to be caught by the rotor vanes with suflicient certainty the root circle F of the vanes would have to lie inside the points 6 f and the top circle K of the vanes would have to lie outside the points al it, that is to say, the rotor vanes would require at least a radial width M1, which is considerably greater than the radial width at of the nozzles Fig. 1. But as is clearly evident from Fig. 3, in that case there would remain above the points al and 6 respectively below the points 0 and 9 a large empty space not filled by the flowing steam. The jets flowing out of the nozzles would not at all fill the rotor buckets correctly and rub against adjacent stationary parts of the steam, and this naturally would result in considerable dispersion and vortex losses, and consequently in a very bad degree of efficiency. I

The essence of the present invention now consists in giving to the nozzles such a position, that the jets issuing from them do not strike the plane C D of the rotor in the way shown in Fig. 3, where the two adjacent figures of intersection I and II appear to be twisted out of the mean circular ring ina direction contrary to the movement of a watch hand, but on the contrary so that the figures of intersection I and II fall entirely or at least with any desired approximation into a circular ring as shown in Fig. 4. This desired Fig. 4 is obtained from the unfavorable Fig. 3 on the drawing by twisting the intersection figures around in the direction of the movement of a watch hand, which in this case is the same as twisting them in the direction of the rotation of the rotor, indicated by the arrow, Fig. 4. Actually the intersection figures I and II will assume the positions shown in Fig. 4, if the outlet sections of the nozzles are bodily twisted from the positions shown in Fig. 1, in the direction of a watch hand into the positions represented in Fig. 5. Naturally an intermediate course may be adopted and the nozzles be bodily twisted to a less Copies of this patent may be obtained for extent in the direction of the rotation of the rotor, so that they occupy relative positions between those of Figs. 1 and 5. This will have the result, that the vanes of the rotor are encountered by jets of steam, the intersection figures of which with the inlet plane of the rotor are turned by a small amount in the opposite direction to the rotation of the rotor and assume a position relative to each other lying between those shown in Figs. 3 and 4. The amount of the twisting does not affect the essence of this invention.

This form of construction of nozzles is particularly advantageously employed in action turbines having a comparatively small diameter of rotor, large pitch of vanes and large axial distance between the nozzles and the rotor.

Instead of being confined by arcs a, 0?, respectively b, c, Fig. 5, the nozzles may obviously be confined by a straight line or any intermediate curve.

The same arrangement may without alteration be applied to axial-flow turbo-compressors.

Having now described and ascertained the nature or the said invention and in what manner the same is to be performed, I declare that what I claim is Nozzle ring for axial-flow turbines and turbo-compressors having the separate nozzle sections turned somewhat in regard to each other out of their middle circle in the same direction as the rotor rotates.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

HEINRICH BOLTSHAUSER. l/Vitnesses:

HULSREICH KELLER, ARTHUR J. BUNDY.

five cents each, by addressing the Commissioner of Patents, Washington, D. G.

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