Improvements in Steam or Gas Turbine Wheels.
Year: 1892

page_text: COMPLETE SPECIFICATION.
Improvements in Steam or Gas Turbine Wheels.
I, CARL GUSTAF PATRIK DE LAVAL of No. 164 Handverkaregatan, Stock-
holm, Sweden, Dr. Phil. and Engineer do hereby declare the nature of this inven-
tion and in what manner the same is to he performed to be particularly described
and ascertained in and by the following statement :-
The present invention refers to an arrangement of the buckets of a steam or
gas turbine wheel and has for its object the possibility of making the buckets
sufficiently strong and to give the whole turbine wheel an increased firmness in the
case where the wheel has a narrow partition and the buckets are made of a desired
length and shape. The invention consists in making the buckets loose or separate
instead of as usual in one piece with the body of the turbine, which loose buckets
On the accom-
then are secured at the turbine wheel in any convenient manner.
panying drawing Figure 1 is a view of a turbine wheel showing some of the
buckets in section, Figure 2 is a section of the wheel, Figure 3a section on the
line 1-2 of Figure 1, and Figure 4 an end view of a few buckets. The body of
the turbine wheel made in two pieces A and B each of them thicker at the
centre and held together by means of a nutshaped shoulder C at one end of a
bush D passing through the centre of the wheel and a nut E screwed on to the
other end of said bush. The inside of each piece A and B is provided with a
recess near the circumference, which recesses when the plates are together form a
deep groove, in which the loose buckets F can be inserted and secured. For this
purpose the buckets are provided with a stem the size of which corresponds
with the dimensions of the aforesaid groove. The buckets themselves have the
same shape as is usual for that kind of wheels.
a
For the purpose of obtaining a closed channel for the fluid running transversally
through the turbine wheel, the buckets may if desired be provided with
projection or cover F³ so that on inserting the buckets into the recess of the wheel,
an envelope is produced around said wheel.
In order to prevent the buckets from radial dislocation outwards, which they
would be liable to through the centrifugal force and insufficient tightening of the
pieces A and B, the aforesaid stem may be made broader at the base than
higher up near the curved portion forming the buckets and the inside in the recess
of each pieces A and B turned out so as to fit; or as shewn in the drawing the
stems F may be provided with a certain number of saw teeth shaped or similar
projections G fitting into a corresponding number of grooves H turned in the
sides of the pieces A. and B.
The body of the turbine wheel may likewise be made in several for instance in
three parts, namely two pieces like A and B with a thin plate inserted between
them. In this way the pieces A and B do not require to be turned out in order
to produce a deep groove between them for the purpose of securing' the buckets
but only be provided with concentric grooves near the circumference in order to
hold the buckets. The recess at the circumference is obtained by interposing the

page_text: aforesaid plate between the discs A and B. The parts may also be held together
at the circumference instead of as shewn at the centre of the wheel.
The turbine wheel may also be made in only one piece, which is provided with a
recess made deep enough so as to permit the inserting of the buckets due to the
elasticity of the edges of the wheel at each side of said recess. The buckets are
then secured by rivetting the wheel together near the circumference.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
ciaim is
First. The combination with a steam or gas turbine wheel of loose or separate
buckets which are held or secured in a corresponding groove or recess in the body
of the wheel, substantially as set forth.
Second. The combination with a steam or gas turbine wheel formed with a
groove or recess at or near the circumference of the wheel of loose or separate
buckets which are held or secured in said recess by means of a stem on the
buckets and furrows in this recess having a saw-tooth section gripping into corre-
sponding furrows in the stems of the buckets substantially as set forth.
Dated this 28th day of July 1892.
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.