US1266973A - Nozzle construction for elastic-fluid turbines. - Google Patents

Description

J. F. METTEN.

NOZZLE CONSTRUCTION FOR ELASTIC FLUID TURBINES.

APPLICATION FILED MAR. 23. ISIT,

Patented May 21.1918.

JOHN F. METTEN, OF PHILADELPHIA, PENNSYLVANIA.

NOZZLE CONSTRUCTION FOR ELASTIC-FLUID TURBINES.

Application filed March 23, 1917.

T 0 all whom it may concern.-

Be it known that I, JonN F. Mn'rrrnv a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Nozzle Constructions for ElasticFluid Turbines, of which the following is a specification.

The rincipal object of my invention is to provide a new and improved construction for the nozzles of steam or other elastic fluid turbines. Another object of iny invention is to provide a nozzle that can be manufac tured by machine processes alone, insuring great accuracy and eliminating all possibility of breakage in service.

The construction is specially adaptable to nozzles of the initial ahead stage or reverse stages of marine turbines Where the pressure drop and expansion ratio is fairly arge. The usual construction for such noz- Zles is to cut the passages from solid or partially cored castings or to cast plates of proper shape into the material forming part of the nozzle. With a pure cast nozzle the partitions dividing adjacent. channels are subject to breakage due to initial casting strains. With the cast-in plate type the sun faces of passages are diflicult to finish properly and accurately, and there is also the possibility of breakage due to defective casting-in of the plates.

In the present invention the nozzle is assembled from wholly machined parts, being free of all inherent casting troubles, and can be fastened as a unit to turbine casing or diaphragm in any approved manner.

The invention can best be described in com nection with the accompanying drawings, of which- Figure 1 is a section of the nozzle taken on line 1-1 in Fig. 3 but lookin in the direction of the arrows, showing tie contain in rings in section;

2 is an elevation of the nozzle looking fro the exhaust side;

Fig. 3 is a developed circumferential sec-- tion of nozzle taken on pitch line 33 in F' s. 1 and 2;

g. 4 is a view of one of the blades seen ed ewise;

ig. 5 is a side view of one of the blades. Fig. 1 is drawn on the assumption that all points depicted therein have been carried Specification of Letters Patent.

'l'aten'tctl May 75!, HHS.

Serial No. 156,835.

along respective circumferences having a common axis so as to bring such points into the plane of the drawing.

The nozzle is made up from an outer circumferential ring 1, either solid or segmental, and an inner circnnifercntial ring 2, either solid or segmental and a nnn-ihcr of machined plates 3. The rings have llangcs 4 and 5, and holes (3 and T forreceiving bolts for fastening the nozzle to the turbine casing or diaphragm. The inside sin-l" ass s. and 9 are s g nerated that ihcir intersect i n with the front sides ii of plains. .wi to a prescribed angle. form straight llnl's. idiots W are milled obliquely to a uni Form depth int the generated surfaces a and J for receiving the plates 3. lo generate lllt con entric snr faces 8 and 9 as described almvc, a tool of a width equal to. the radial distance between the two surfaces is fed on the same angle as prescribed for the blade carrying slots.

Outside circumferential gXOOWJs ll Mod 312 partially intersect the inner slots .10, pern1itting the edges of plate b to project through at these places. These ii-trtcnded portions l? and i i are riveted over when. in lace thus fastening all the parts togrthar as one unit Each plate 3 is idcnliml and ha;-v tin; F rm as shown in Figs. 3 and i. Th front side of each partially milled out toward llm" exhaust end forming a Wedge shaped ch ne no] 15 for giving the desiwd expansion ratio t the steam passage. This necessitatcs plate of some thickness dependent on the desired expansion ratio.

The middle portion of the inlet end 16 is rounded on the back side to form easy entrance of steam. The extensions 17 and 18 at sides are for cmnplctely filling the slots in the inner surfaces and preventing restriction to flow of the steam at nozzle entrance.

This ci'n'istruction nozzle permits of the most suitable metals being used for the rings and plates as the fabrication does not depend on the relative. melting temperatures as in a cast-in plate nozzle. Present practice indicates that mild steel is most suitable for the rings and brass composition. for the plates as best to resist the action of the steam.

The assembly of the nozzle is easy. The rin s are clamped in their relative ositions an the plate inserted endwise an riveted as previously described.

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