IMPROVEMENTS IN STEAM ENGINES
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by Konrad Wilhelm Jurisch and
John Henry Lewis at the Office of the Commissioners of Patents on the 19th
October 1880. Partly a communication from abroad by Dr. Wilhelm Rudolph
Proel and Carl Joseph Scharowsky, Civil Engineers, of Dresden, in the
German Empire.
KONRAD WILHELM JURISCH, PH.D., and JOHN HENRY LEWIS, both of Widnes,
in the County of Lancaster. "IMPROVEMENTS IN STEAM ENGINES." [Partly a
communication from abroad by Dr. Wilhelm Rudolph Proell and Carl Joseph
Scharowsky, Civil Engineers, of Dresden, in the German Empire.]
Our Invention relates to a system of steam engines in which the waste steam is
partly returned to the steam boiler from which the engine is supplied, such return
being effected by means of an injector worked by steam from a high pressure
boiler.
We employ a high pressure boiler of any suitable form, sectional or of other
construction, adapted to sustain a high pressure to generate steam for working the
engine as well as the injector. The engine is however not supplied directly from
this boiler, but from a boiler connected in a special manner with the former, and
containing steam which is maintained at a lower pressure than the steam in the
high pressure boiler. The steam from the low pressure boiler passes through a pipe
into the engine cylinder, and after having acted within the same in the ordinary
manner it is exhausted into a reservoir. From the latter the injector (or steam
jet apparatus), worked by steam from the high pressure boiler, draws a part of the
exhaust steam into the low pressure boiler, the remaining portion of the exhaust'
steam from the reservoir passing off into the outer air by a valve, or into a
condenser.
The low pressure boiler in which the steam is maintained at an ordinary
pressure of, for instance, from 4 to 6 atmospheres, is or may be heated by the com-
bustion gases from the high pressure boiler, which can be conducted either around
the said boiler or into a flue by means of a valve. This low pressure boiler may
however have a grate of its own.
The reservoir is provided with two valves, one of which allows the steam to pass
into the suction pipe of the injector, and which prevents any accidental access of
high pressure steam into the reservoir; the other valve serves to regulate the

page_text: pressure in the reservoir, and has therefore to be loaded to the degree of pressure
required, which, according as the engine is provided with a condenser or not, is
kept at a fractional part of an atmosphere, or somewhat above the atmospheric
pressure.
For the purpose of utilizing the heat given off by the walls of the said reservoir,
the same may be fitted with a waterjacket, in which the feed water supplied by
the feed pump is heated, this water being thereupon conducted to the high pressure
boiler by a pipe; or the reservoir may be covered with a clothing of bad con-
ductors of heat. The feed water when not circulating through the jacket of the
reservoir may be heated by any suitable feed water heater, into which the steam
passing off from the reservoir is directed.
The injector has to be regulated by its cocks in such a manner that the amount
of steam supplied by it, together with the steam which may be generated in the
low pressure boiler, is as nearly as possible equal to the quantity consumed by the
engine. The evaporation in the low pressure boiler is however of entirely sub-
ordinate importance as long as the supply from the high pressure boiler and the
reservoir balances the consumption in the engine. But whenever variations in the
supply or in the expenditure of steam occur, and in consequence thereof the
pressure in the low pressure boiler decreases or increases, the large quantity of
water in this boiler (which is of a temperature corresponding with the normal
working pressure) serves in the one case to make up for the deficiency by
generating an additional quantity of steam under the decreased pressure, or in the
other case by condensing the surplus quantity which is of a temperature above the
mean. For contributing to the regulation of the steam pressure in the low.
pressure boiler this boiler may however be provided with suitable armatures, such
as self-acting apparatus operated upon by the steam pressure, and serving to
regulate the valve admitting the combustion gases from the high pressure boiler.
Moreover the steam spaces of the two boilers may be connected with each other by
a pipe, in which a pressure regulator is inserted for allowing steam to pass from the
high pressure to the low pressure boiler whenever the pressure in the latter
becomes too low.
Considering that in the ordinary course of working the evaporation in the low
pressure boiler is insignificant, and that besides, a certain quantity of water is
almost invariably carried over with the steam from the high pressure boiler, the
low pressure boiler does not require to be regularly supplied with feed water. But
to make up-for any lack a communication may be established between the water
spaces of the two boilers by a pipe which must have a pressure regulator fitted to
it in a similar manner as the aforesaid communicating pipe between the steam
spaces.
If it should be preferred the feed water may first be introduced into the low
pressure boiler, and thence forced by a special pump into the high pressure boiler.
When the described system is to be applied to engines with intermittent motion,
such as direct acting pumping engines, the injector should be provided with a
suitable contrivance for causing it to operate during the actual working periods of
the engine only.
The following considerations will show the advantages of our Invention :-
When steam of very high pressure, such as may be generated in a so-called
safety boiler, is utilized directly and expansively in a steam engine, the heat of the
steam decomposes the lubricating material and burns the packings, in consequence
whereof the wear on the cylinder, the piston, and other parts is excessive, and
leakage of the stuffing boxes, &c., unavoidable.
Moreover the strength of the parts of the engine having to be in proportion to
the initial pressure of the steam, the whole engine becomes very heavy and
bulky.
In an engine of our system the high pressure steam is utilized quite as efficiently
as in an expanding steam engine. The work which the steam from the high
pressure boiler bas to perform in drawing wasto steam from the reservoir is fully

page_text: compensated by the increase in the quantity of operative steam thus obtained,
which increase is in proportion to the difference of pressures in the two boilers
(supposing all other conditions to be alike). The systein consequently allows the
full advantages to be realized which the use of high pressure steam presents with
regard to consumption of fuel, but without being subject to the inconveniences
connected with the direct introduction of such steam into the cylinder.
The system also presents advantages with regard to security against danger from
explosion otherwise connected with high pressure boilers sufficiently capacious to
contain the quantity of steam and water required for a uniform working of the
engine. The high pressure boiler, when belonging to the class of boilers called
sectional or tubular safety boilers, is secure by its construction, whereas the low
pressure boiler, whose contents of water and steam is to compensate for the
unavoidable deficiency in the high pressure boiler, is neither oxposed to a high
pressure nor to any material wear by the mode of heating the same.
Instead of combining together but one boiler of either class with a single steam
cylinder and with one injector and one steam reservoir, two or more of any or all
of these parts may be used, and the different cylinders may belong to one or to
different engines. For locomotive purposes it may also be advantageous to combine
a high and low pressure boiler together in one construction.
The described Invention is an improvement upon a former Invention, for which
Patents were granted to two of us, namely, to K. W. Jurisch and J. H. Lewis, in
England on the 14th September 1877, and in Germany on the 4th January 1878,
the present improvement consisting essentially in the application of an injector in
place of an exhausting and compressing pump, and in the introduction of the
reservoir into which the engine exhausts.