US1313152A

US1313152A - Harold e

Info

Publication number: US1313152A
Authority: US
Publication date: 1919-08-12
Anticipated expiration: 1936-08-12

Description

H. E. YARHUW.

TURBINE BLADE. APPLICATION FILED JUNE 5. 19%8.

Patented Aug. 12, 1919.

HAROLD E. YABROW, OF GLASGOW, SCOTLAND.

TURBINE-BLADE.

Specification of Letters Patent. Patented Aug. 12, 1919;

Application filed June 5, 1913. Serial No. 238,347.

To all whom it may concern:

Be it known that I, HAROLD EDGAR YA R- now, a subject of the King of Great Britain, residing in Glasgow, Scotland, have invented certain new and useful Improvements Relating to Turbine-Blades, of which the following is a specification.

The invention relates to the blades of turbines and more particularly to the form given to the edges of the blades.

It is found that the'blades are crack, especially at the roots of the blades, and this drawback has been accentuated, particularly in marine practice, by the employment of material suited to the use of superheated steam.

The edges of the turbine blades are generally sharp in orderto lessen the losses due to eddy currents, but a sharp edge is not suitable for withstanding stresses, especially variable bending stresses, such as occur in a turbine, since it is well known that slight hair cracks are very liable to be formed in edges and sharpcorners. and, when once formed, extend more deeply.

According to the invention this drawback is obviated by rounding the edges of the blades for a small portion of their length at the end projecting from the drum or casing to which the shank of the blade is secured. As this rounded portion is confined to a short length of the blade and the rest of the edges of the blade is quite sharp, no appreciable loss is incurred by the eddies.

liable to The accompanying drawing shows an example of the improvement according to the invention, in which Figure 1 is asectionof a blade as usually fitted showing at A the sharp edges of the blade. Fig. 2 shows at B 5 those edges rounded off at the part where the blade is secured to the drum or casing.

Figs. 3 and 4 are two elevations at right angles of the blade.

As shown more particularly in Fig. 4:, the rounding may terminate in a comparatively sharp curve, as shown by the full lines at C,

and by a long taper, as shown by the broken me. from 10 to 25 per cent. ofthe total length of the blade. 7

Having now described the nature of the said invention and the best means I know of citrrying the same into practical effect, I 0 aim Y A turbine blade, the edges of whichare.

rounded for a short portion of their length at the end projecting from the drum or cats ing to which the shank of the blade is secured.

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

HAROLD E. YARBOW.

Witnesses:

JAMES. RITCHIE, J. W. BLAcK;

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, 1).,0. r

The rounded portion C D may be