Bauer-Wach Exhaust Turbine System
This is a marine propulsion system developed by Gustav Bauer-Schlichtegroll.
EXHAUST TURBINE EQUIPMENT ON S.S. “BRITANNIA.”
'By interpolating an exhaust steam turbine between the low-pressure cylinder and the condenser, and coupling it by reduction
gearing to the propeller shaft, some 30 per cent, more work can, in favourable cases, be obtained from each
pound of steam passed through the combined system, by Dr. Bauer stated in his paper that the plan in question had originated with Sir Charles Parsons, but the credit for the practical application of the idea appears to rest with the Vulcan yard. Particulars were given of two steamers, each of 9,080 tons deadweight, which were thus converted at this establlishment. In their original condition, these engines developed about 2,605 indicated horse-power, and drove
their ships at a speed of 14 knots. By the addition of
the exhaust turbine, the horse-power, with the same consumption of steam, was raised to the equivalent of
3,590 indicated horse-power, and the speed to 15 knots.
The one difficulty encountered in making this combination, lies in the fact that, owing to inequalities in the
torque, the speed of a reciprocating marine engine is not
constant, but varies cyclically throughout each revolution. The turbine, on the other hand, develops a uniform
torque, and owing to the large amount of kinetic energy
stored in its rapidly rotating rotor, its speed tends to
be very uniform. Hence, in order that the turbine
and the reciprocator shall work satisfactorily together,
there must be considerable elasticity in the coupling
between the two. In the case of the Vulcan sets above
referred to, this elasticity was provided by the use of
a Föttinger hydraulic coupling.
In view of the success thus attained in Germany, it is
of interest to note that Messrs. William Beardmore and
Company, Limited, of the Naval Construction Works,
Dalmuir, have now applied the system to the Anchor
liner Britannia, a ship of 8,464 tonnage, launched only
two years ago. .....
As already noted, the installation of the exhaust turbine
increases the horse-power developed by the same
quantity of steam by an amount which, in favourable cases, may attain 30 per cent. The corresponding
gain in economy is stated by the builders to range
between 18 per cent, and 25 per cent., depending on the
type of engine converted. Owing to the uniform
torque of the turbine, the racing in a seaway is
reduced, and higher average speeds can be maintained.'[1]