An Improved Power Transmitting Arrangement for Compound Steam Turbines.
Year: 1897

page_text: Date of Application, 28th Sept., 1897-Accepted, 30th Oct.,
1897
COMPLETE SPECIFICATION.
An Improved Power Transmitting Arrangement for Compound
Steam Turbines.
I, EBERHARD SEGER, of Kammakaregatan 40, Stockholm, in the Kingdom of
Sweden, Engineer, do hereby declare the nature of this invention and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement:-
The present invention relates to an arrangement to be applied to compound
steam-turbines, in which the steam acts simultaneously on two adjoining turbine-
wheels rotating in opposite directions, for transmitting the power received by these
two wheels, to one shaft. In steam-turbines the power is usually transmitted from
the turbine-shaft to the main-shaft by means of toothed gearing, though this
practice is not to be recommended since the gear teeth owing to their great
velocity frequently break rendering the motor unserviceable. For this reason,
the use of a belt for the power transmission is preferable, more especially as a
broken belt can be replaced or repaired without appreciable expense or loss
of time.
In the accompanying drawings,
Figure 1 illustrates a longitudinal section of a compound steam-turbine pro-
vided with the arrangement referred to and,
Figure 2 an end-view (partially in section) of the same.
a and b are the two turbine-wheels which by the steam passing through are
caused to revolve in opposite directions, as indicated by the arrows in Figure 1.
Their shafts and d, (which are horizontal in the turbine illustrated in the
drawings) point in opposite directions and on each of them is secured a belt-
pulley e, f of a diameter proportioned to the respective velocities of the two
turbine-wheels so as to give the same velocity to the peripheries of the two pulleys.
Below, above or at one side of these wheels there are placed two
pulleys gh one of these (h in the drawing) being fixed to a shaft i rotating in
fixed bearings and provided with a driving-pulley k. The other pulley g, on the
other hand, is secured to a short shaft which may also be journalled in a fixed
bearing, though the better plan is to journal it, as shown in the drawing, in a
sliding carriage Z arranged in the engine-frame in such a manner that it can be
moved towards or from the axis of the turbine-wheels thus retaining an even
tension in the belt wrapped around the pulley 9. When the latter is located
below the turbine-wheels so as to be suspended in the belt, as in the drawing, it
will maintain an even tension on the belt by virtue of its own weight; if this is not
the case, the tension may be kept uniform by means of a spring or weight tending
to force the carriage together with the pulley 9 outward from the axis of the
turbine-wheels. Around the four pulleys e, f, g and his wrapped a belt passing
from the pulley f around the reverse side of the pulley g, then over the pulley
on the same side as over f, and finally reaching the pulley f on passing around
the reverse side of the pulley h. By this method the power is transmitted from
the turbine-wheels, rotating in opposite directions, to the shaft i and the driving-
pulley, attached to it. The tension required in the belt for producing the

page_text: necessary friction between belt and belt-pulleys may also be brought about by
means of any ordinary belt-tightener in place of using the adjustable pulley y.
The inventor is aware of the fact that it has been practised to use a single belt
carried around several belt-pulleys, 'for instance, in drilling machines, for the
purpose of dispensing with one of the cone-pulleys usually employed for varying
the speed of the machine, by substituting for said cone-pulley a movable jockey
or tightener-pulley which may be adjusted according to the position of the belt
on the cone-pulley and which in combination with a number of idle-pulleys
allows of maintaining a uniform tension on the belt. This arrangement differs,
however, from that here referred to in that, while in the former case the power
is derived from a single belt-pulley and transmitted over a number of idler-
pulleys to a cone-pulley, the power, in accordance with this invention, is derived
from two belt-pulleys e and fand transmitted over a single idler-pulley (at the
same time acting as a jockey or tightener-pulley) to the belt-pulley h of the
engine-shaft.
.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:-
:―
In compound steam-turbines, an arrangement for transmitting the power
received by the two turbine-wheels a, b. to one common shaft i, consisting in the
two turbine-wheels, which rotate in opposite directions, being mounted on
oppositely projecting shafts each carrying a belt-pulley e, f of a diameter suited
to the differing velocities of the two wheels, and the said pulleys being encircled
by one common belt which in its course from one belt-pulley to the other on one
side passes around a pulley g and on the other around a belt-pulley h secured to
the above-mentioned shaft i.
Dated this 20th day of September · 1897.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.