Improvements in and relating to Methods and Apparatus for, Exhausting in the Steam the Energy of Superheated Cylinders of all Types of Steam-engines without Detriment to the same.
Year: 1896

page_text: Date of Application, 20th June, 1896
Complete Specification Left, th Mar., 1897-Accepted, 5th June, 1897
PROVISIONAL SPECIFICATION.
Improvements in and relating to Methods and Apparatus for,
Exhausting
in the
Steam
the Energy of Superheated
Cylinders of all Types of Steam-engines without Detriment
to the same.
1, WILHELM SCHMIDT, of Ballenstedt on the Harz, in the. Duchy of Anhalt,
German Empire, Civil-engineer do hereby declare the nature of this invention
to be as follows:-
The object of this invention is to provide means, by the aid of which may be
solved the problem of employing superheated steam in engines of any kind without
detriment to the cylinders, and of fully exhausting the energy of said steam by
doing away with an undue condensation of the same.. The problem proper to he
solved is: To be able to employ superheated steam of any attainable height of
temperature in the cylinders of ordinary single- and double-acting engines, as well
as in double, triple, or multiple expansion engines, and to attain at the same time a
greater energy and a more economical exhaustion than has been attained with
saturated steam up to now. In view of the entire novelty of the idea of invention,
and in order to afford an easier comprehension of the particularity as well as of the
importance of the same, I prefer, first of all, to explain the general points of view
according to which that which is known in the domain of superheated and of
saturated steam shall be improved, not only with regard to the aim intended, but.
also to the means for reaching that aim.
In the very best compound engines at present known the indicated work of steam
in the cylinders amounts in, average to only 75% of what should be gained
according to the theoretically possible fall of temperature. Provided, for
instance, that if the engine be a condensing engine, the steam may have an
absolute tension of 10 atmospheres (about 180° C.), and the temperature in the
condenser be about 60° C., the fall of temperature will be
180 60 120° C.,
but the work of steam utilized therefrom corresponds in the main to a temperature
of about 90° C. only. In most cases, however, the exhaustion is considerably
lower. If one succeeded in practically exhausting the theoretical work of steam,
ie. the whole work of steam without the arising of water of condensation, a fall
of temperature of about 90° C. might be attained with balf the tension afore
mentioned, or with an absolute tension of 5 atmospheres respectively, because
this tension corresponds to a temperature of about 150° C. The fall of temperature
is thus
150 60 90° C.
The difference between the theoretically possible exhaustion of the work of
steam and the best. exhaustion attained up to now is still greater, if steam of a
still higher tension is employed. Assuming a tension of 15 atmospheres, the fall of
temperature is

page_text: At the best 75%, i.e. 105° C. are exhausted, but this fall of temperature (105° C.).
corresponds already to an absolute tension of 7 atmospheres, viz.:
Therefore, considering the fall of temperature, saturated steam of 15 atmospheres
used in a condensing triple expansion engine cannot do more than can be done
by steam of 7 atmospheres in a condensing double expansion engine, if one succeeds
of coming near to the theoretically possible work of steam. Under this supposition
the energy of saturated steam of a tension of 25 atmospheres (the fall of temperature
of which requires already a compound engine with not less than 4 cylinders) may,
from an economical point of view, well be opposed to the energy of steam having
an absolute tension of 11 atmospheres, and acting in a double cylinder compound
engine.
The reasons for that imperfect exhaustion of the energy of the steam are the
great losses of heat caused by the condensation of steam within the cylinder. The
means for reducing said losses (furnishing the cylinders with steam-jackets;
employing the steam three or four times in engines with three or four cylinders,
and heating the receivers) have practically come to a limit already.
Such and other considerations and researches, and also the certainty that a further
material development of the steam engine cannot possibly be attained on the way
chosen hitherto, led me, many years back, to trials with superheated steam,
although such use of steam had at that time been given up in consequence of the
great difficulties connected with the generation, employment, and exhaustion of the
said steam. The progresses resulting from said trials reside mainly in the means
and methods for the generation of highly superheated steam, and for the non-
detrimental application of the latter in single-acting engines. The limit of what has
been attained by me up to the present in the domain in question is the compound
engine and boiler for superheated steam described by Professor Schröter of Munich
in volume 39 (1895) of the "Zeitschrift des Vereins Deutscher Ingenieure "
(Journal of the Association of German Engineers).
The highest aim now to be reached is to obtain in a simple manner a practically
perfect and non-detrimental exhaustion of the energy of highly superheated steam
of a high tension in the working-cylinders of double-acting double-expansion and
especially triple-expansion engines. To reach that aim there is, however, requisite
a particular regulation of the temperature of the superheated steam on entering
the cylinder. The manner of said regulation may be dependant on the particular
type of engine, but is in any case dependant on the degree of filling of the
cylinder or cylinders of that engine with the superheated steam. The invention
proper resides, therefore, in methods and means that affords an advantageous or
nen-detrimental application of highly superheated steam, and an exhaustion of
the high energy of the latter, in all types of engines, especially double-acting
engines and multiple expansion condensing engines, by regulating in a particular
way the temperature of the superheated steam on entering the cylinder of the engine,
said regulation being made dependaut on the degree of filling of that cylinder, and
being controlled in such a manner that the expanding steam remains dry whilst
performing the greatest part of the work possible during one stroke of the piston,
the rest of said work being performed by expanding saturated steam.
To show more clearly the significance of the above manner of regulating the
temperature of the superheated steam (on entering the cylinder) according to
the degree of filling, I will first give in the following some examples therefore; the
figures cccurring in the latter are determined so as to yield a perfect dryness of
the steam during the first half of the path of the piston.
Saturated steam having an absolute tension of 10 atmospheres (on entering the
cylinder) suffers a decrease of tension down to 6 atmospheres whilst the piston.

page_text: makes half its way, provided, the degree of filling amounts to 30%. The fall or
temperature is thus about
180 159 21° C.
=
If, now, with the application of said degree of filling (30%) a condensation of
steam on the first half of the way of the piston shall securely be avoided, the steam
should be superheated (according to the diameter of the cylinder) for about the
fourfold amount of the fall of temperature. The temperature of steam of an
absolute tension of 10 atmospheres (on entering the cylinder) is thus to be (for a
degree of filling of 30%):
Therefore, the temperature of superheated steam of an absolute tension of
10 atmospheres (on entering the cylinder) should be (for a degree of filling
of 20%):
The above few examples distinctly show the importance of regulating the
temperature of the superheated steam (on entering the cylinder) according to the
degree of filling. Said examples show, further, that slightly below a degree of
filling of 15% there must practically lie the lowest limit for the exhaustion of
highly superheated steam, because materially higher temperatures cannot continu-
ously be attained. The temperature of the steam (on entering the cylinder) must,
however, be materially higher, if the degree of filling amounts to less than 15%
and if a condensation of steam in the first half of the cylinder (with regard to the
direction of motion of the piston) shall be avoided.
In the theoretical working diagram represented in Figure 1 (this figure is duly
enumerated in the short description of the figure hereinafter following, but must
be referred to now on 'account of the deductions to be drawn therefrom) the dotted'
line a- represents the specific volumes of the steam. In reality, the effect
remains widely behind said ideal line a-b in consequence of the abundant
condensation of saturated steam that occurs in the cylinder mainly instantly after
the inlet as well as during the first period of expansion. The real effect yielded by
the very best compound engines may, perhaps, be indicated by the dot-and-dash-
line ef. The loss caused by the unavoidable condensation of steam during
the first half of the way of the piston may be represented by the curved
quadrangle a-b-c-f-e. The curved triangle a-d-b indicates the increase
in the volume of the steam by the superheating, and the full line d-b represents

page_text: the line of limit for the real effect of the steam if this latter remains superheate
to the middle of the path of the piston. The point of intersection b of the
lines a-b and d-b is the so-called "point of saturation." The work performed by
dry steam is finished at said point ; the superheated steam turns into saturated
steam, aud the rest of the work is performed by expanding saturated steam
according to the established physical law for saturated steam..
It will be found on a closer examination of the diagram in question, that the
work to be performed by expansion during the second half of the way of the piston
is but very slight with regard to the work already performed by the full pressure
as well as by the expansion of the superbeated steam during the first half of the
way of the piston; and, further, that even said rest of work will be without a
material condensation of steam because the saturated steam in the second half of
the cylinder (with regard to the direction of the pistou) is strongly heated by the
comparatively great radiation of heat from the surfaces that have been in contact
with the superheated steam in the first half of said cylinder. The water of
condensation resulting from the expansion of the saturated steam during the second
half of the way of the piston amounts to about 4% only. Such a low percentage
of water of condensation is without importance in view of the whole amount of
work done by the steam during one stroke of the piston; but said low percentage
is, on the other hand, of great importance for the preservation of the sliding
surfaces of the cylinder and other parts. This shows distiuctly, that by regulating
the temperature of superheated steam according to the degree of filling of the
cylinder the rising of water of condensation, and the bad influences resulting
therefrom, may effectively be done away with; or that, in other words, the
theoretical amount of energy of the steam may be fully exhausted. It will later
on be shown, that this full exhaustion may be attained also if the degree of super-
heating is but very low.
If the principle above revealed is employed with double-acting steam engines,
there may be attained some other advantages besides those afore stated. For
instance, by elongating the cylinder as well as the piston in a certain measure, the
drawbacks generally resulting from the application of superheated steam, or of
steam of a high tension (great consumption of lubricants, and endangering of the
sliding-surfaces of the cylinder and other parts), are entirely done away with.
The Figure 2 shows two piston-diagrams (taking one into the other) for super-
heated steam of au absolute tension of 12 atmospheres, and of an inlet temperature
of about 330° C., (this temperature must be chosen slightly higher than the
theoretical temperature in view of the losses caused by the walls of the cylinder),
of the high pressure cylinder of a double expansion engine working with a degree
of filling of 25%. The cylinder and its piston are represented below said diagram.
If the length of the piston is equal to half the way of said piston, and if the
packing rings are arranged in the middle of said piston, there then results the
following:
The tension of said steam gets reduced to 6 atmospheres till half the way of the
piston; the steam has then turned into saturated steam, and possesses on the
commencement of the second half of the way of the piston a temperature of
about 160° C.; that temperature results into an end-temperature of 128° C. if the
counter-pressure at the end of the way of the piston amounts to 2 atmospheres.
The mediate temperature of the steam in the second half of the piston is thus

page_text: for the way of the piston in one direction (as to the temperature of 300° C.
appearing in the above formula I call attention to the fact that till to the
commencement of the period of expansion the steam has cooled by 30° C.), and
to 128° C. for the way of the piston in the other direction, the mediate temperature
for a piston-way corresponding to the line a ¹is
This piston-way is a quarter of the whole way in one direction, and a quarter of the
whole way in the other direction, so that the piston performs the half of a stroke
at a mediate temperature of 179° C. It results from this, that the me liate
temperature of the walls of the cylinder on a whole stroke of the piston is
These examples show convincingly, that by correctly regulating the .inlet;
temperature according to any degree of filling, and by correspondingly elongating
the piston, all difficulties as to the preservation of the sliding surfaces of the
cylinder and other parts are completely done away with; or in other words, that
even with the application of a high superheating of the steam all hurtful influences
may be fully avoided.
If the filling (of the cylinder with steam) is but small, the mediate temperature
on the way of the piston in one direction, and on the way of the piston in the other,
direction, is still smaller than that above stated, although, according to the above
examples the inlet temperature increases strongly if the degree of filling decreases..
Under all circumstances, therefore, the steam keeps its natural property of being
able to serve as a. lubricant within the zone for the expansion of saturated stean,
and it is hereby proved that even a greater consumption of lubricants cannot take
place. If space is wanting, or if one is satisfied with the steam remaining dry
for 40% only of the way of the piston, the length of the piston may be only 33°/
of said way, without attaining a inediate temperature of too high a degree.
It is distinctly to be seen from what has been explained up to this point that the
highest exhaustion of the energy of highly superheated steam may be attained
whilst keeping on a low mediate temperature of the walls of the cylinder; that low
mediate temperature may be below that for saturated steam of the same teusion if
steam jackets are employed.
If the highly superheated steam is to be used in a compound engine, the
regulation of the inlet temperature of that steam may well be effected by trans-
mitting the excess of heat of the steam for the high pressure cylinder to the steam;
contained within the receiver, so as to superheat said latter steam, in such a;
manner, that the course of the work, which the steam performs within the low,
pressure cylinder is similar to the course of the work which the live-steam performs
within the high pressure cylinder. If the inlet temperature is regulated in this
way, that is to say, if the heat of the superheated steam is distributed upon several
cylinders, the fall of temperature of steam having an absolute tension of 12 atmo-
spheres may be exhausted without the arising of appreciable quantities of water of,
condensation in a compound engine with but two cylinders, whereas without the
regulation in question, and with the application of saturated steam, a compound
engine with three cylinders is requisite, even if the degree of exhaustion is assumed

page_text: to be 75% only of the theoretical amount of energy. Moreover, the inlet-
temperature of the superheated steam may be so low as would have been thought
impossible previous to the disclosure of the present invention. The economical
effect in the example last given is equal to that which could be attained in a
compound engine having four cylinders, and working with a steam of a tension of
25 atmospheres, if the distribution of the steam is effected in the manner formerly
employed.
That extraordinary effect resides in the former method of distributing the steam
(saturated steam) allowing of a utilization of a fall of temperature of only 40° C. in
one cylinder, whereas on regulating the inlet temperature according to this
invention a fall of temperature of 70°, and even more, may well be utilized, the
steain being fully exhausted and the inlet temperatures being not too high.
The whole fall of temperature of steam having an absolute tension of
25 atmospheres is
225 60 165° C.
or about 41° C. for each of the four cylinders. The fall of temperature for the
first cylinder is, therefore, from 225 down to 184° C., which corresponds to a
reduction in tension from 25 down to 11 atmospheres. The mediate temperature
of the walls of the cylinder is then about 198° C.,.whereas the mediate temperature
of the walls of the cylinder of a double expansion engine for the use of superheated
steam amounts to 147 5° C. only in those parts of the cylinder that are touched
by the packing rims of the piston, the degree of filling being assumed to be 25%.
It may be mentioned at this place of the specification, that another advantage
of the novel arrangement resides in the differences of tension being lower with
superheated steam than with ordinary saturated steam, which permits of the
packing rims of the piston being pressed against the cylinder with a lower force
than otherwise requisite. In the 'examples afore given the difference of tension
is 25 11°14 atmospheres in one case, and 12-259-5 atmospheres in the
other case.
The special advantage (concerning the reduction of the differences of tension
afore mentioned is still greater, if the novel method of regulating the temperature
of the superheated steam is applied to steam of a tension of about 20 or more.
atmospheres, in that in such a case a triple expansion compound engine may
perform more than a four-cylinder compound engine working with saturated steam.
Whilst the fall of temperature in the cylinders of a double expansion engine.
working with steam of an absolute tension of 12 atmospheres amounts to
still 64° C., the fall of temperature for each cylinder of a triple expansion engine
working with steam of an absolute tension of 12 atmospheres amounts to no
more than 51° C. The inlet temperature of the steam amounts to 330° C.,
if a double expansion engine is driven with a degree of filling of 25% by steam
having an absolute tension of 12 atmospheres; if, however, steam having a
tension of 20 atmospheres is employed in a triple expansion engine, the fall of
temperature amounts to only 300° C.
It is at present possible to generate superheated steam having a temperature of
380° C., and, therefore, in the first of the two cases last mentioned there may be
utilized 50° for superheating the steam within the receiver, whereas in the second
case even 80° C. may be utilized in that way.
With triple expansion engines that are subjected to a strongly varying strain,
and in which greater degrees of filling (about from 33-40%, especially for the
high pressure cylinder) are used, there may be employed still lower initial
temperatures than are at disposal for regulating the degree of superheating by
distributing the heat of the steam in such quantities, that even with a very
strong variation in the strain of the engine a correspondingly varying super-
heating of the steam within the receiver may well be effected. Very much the

page_text: same circumstances apply to large engines with an unvarying degree of filling.
If a big triple expansion marine engine is to be driven by superheated steam, the
attendance of the superheaters for that steam is difficult, in view of the co:n-
paratively great number of the same, as resulting from the comparatively great
number of boilers necessary for producing the steam to be superheated.
By employing in such a case suitably greater degrees of filling, one may get
(without an appreciable loss of energy) so low an initial degree of temperature,
that the generation of the superheated steam having that low degree may in any
case be securely attained. If, perhaps, in certain cases the excess of heat of the
superheated live-steam should not be sufficient for superbeating the steam within
the receiver in a suitable degree, then the correct initial temperature of the steam
for the next following cylinder may easily be attained by providing a special
superheater for the receiver. It is, however, to be preferred to let the superheated
live-steam have such an initial temperature, that the steam within the receiver may
well be sufficiently superheated.
In general, on producing superheated steam, the degree of superheating should
be chosen as high as attainable from the superheater employed, without endangering
the latter. The superheated steam will, therefore, generally possess a temperature.
of from 350-380° C.; such temperatures are fully sufficient for enabling the stean
to remain dry down to half the way of the piston, even if the degree of filling used
is very low, for instance 15% If the degree of filling is greater, there then
exists an excess of heat that may be utilized in a great variety of ways. If
instead of a triple or double expansion engine a single expansion engine is.
employed, the regulation of the initial temperature (according to the idea of this
invention) may be effected in another way, for instance by mixing the superheated
steam with wet steam, in varying degrees, corresponding to the varying degrees of
filling of the respective engine; but the excess of heat existing at a given time-
may, if desired, be transmitted to feed water, or be utilized, and removed from the
steam, in any other suitable way. The means for effecting the regulation in one or
the other manners may be adapted to be, operated either from hand or in an
automatic way, as may be found best suited for the particular case.
In locomotive engines, for instance, the initial temperature may be regulated (in
a sense according to the idea of invention) from hand by operating the regulating
device for the superheater proper in such a manner, as to adjust said regulating
device in accordance with the position of the distributing lever of the locomotive
engine. In other words, said regulation and adjustment is to be effected in such a.
way, that the superheated steam remains dry down to half the way of the piston,.
or does not prior thereto turn into saturated steam respectively.
The same mode of operation may be used with many other types of engine, in
which either the variation of strain is but very slight, or in which an equally great
degree of filling is maintained for a comparatively long time. The best mode of
operation will however be in any case letting the regulation of the temperature of
the steam be effected by the steam distributing device of the respective engine,.
supposing the latter be an expansion engine, and I think I may mention at this.
place that said steam distributing devices are supplemented or completed by my
present invention in quite a remarkable degree. The value of said devices is
greatly increased by the latter being made able to regulate automatically the
initial temperature of the superheated steam according to the varying degrees of
filling of the respective engine. Anyhow, to effect that automatic regulation there.
need not indispensably be employed the steam distributing device proper, but any
other part, the position of which depends on said device.
In some cases the automatic regulation may be effected by making use of the
variations of pressure of the steam within the main inlet pipe, in that for instance
said variations are employed for operating an automatic valve that controls the
admission of wet steam to the superheated steam, as already afore mentioned.
In order to make my invention more clear, I refer to the accompanying drawings,

page_text: in which similar letters denote similar parts throughout the different views, and in
which-
Figure 1 shows a diagram that has already been referred to in the above
preamble.
Figure 2 shows also a diagram, together with the cylinder and piston of a steam
engine, the said cylinder being in longitudinal section. Also these parts have
already been herein before referred to.
Figure 3 shows a vertical section, through a generator for superheated steam,
together with some parts of an engine intended to be driven by such steam, and
together with the mechanisms for regulating the inlet temperature of the
superheated steam according to the principle of the present invention.
Figure 4 is an outer view of the steam generator shown in Figure 3, in which
the mechanisms for effecting the said regulation differs from that shewn in the
said figure.
Figure 5 is a vertical longitudinal section through the valve i of Figure 4, drawn
on a larger scale.
Figure 6 is a longitudinal section through a particular construction of a
steam distributing valve, and through the adjacent portions of the cylinder having
that valve, and
Figure 7 is a section through the receiver of a compound engine, the cylinders
of the latter and the steam pipes between said cylinders and the receiver being
also in sectiou.
Referring to Fig. 3 h is a pipe that connects the steam space of the boiler
proper A with the steam inlet pipe B for the cylinder C. The pipe B is connected
to one end of the superheater D, the other end of which is connected with the
steam space afore mentioned by means of the pipe E. The pipe is furnished
with a valve g that is connected to the lever F of the regulator G by means of the
rod H. Supposing the regulator to act in such a manner as to cause in its turn an
increase of the degree of filling, the valve g will be opened in a corresponding
degree, so as to allow of a certain quantity of wet steam to pass over into the
pipe B, and to mix with the superheated steam flowing through said pipe. The
temperature of the superheated steam is, therefore, reduced in a. measure corre-
sponding to the increased degree of filling. If, on the other hand, the degree of
filling is reduced, the regulator acts upon the valve g in the reverse way, i.e. closes
said valve either nearly or wholly. In the form of construction shown in
Figs. 4 & 5, the variations of pressure caused within the pipes B and by the
influence of the regulator in question, are made use of. For this purpose the
pipe is furnished with an automatic valve i, the valve proper of which is
suspended by a spring i 2. The tension or strain of said spring is so chosen that
the pressure of the wet steam (within the boiler proper A) is not sufficient to open
the valve proper . If however, the pressure within the pipe B gets reduced in
consequence of a sudden increase in the degree of filling of the cylinder C, the
valve proper is raised by the wet steam, and a certain quantity of the latter
passes through the pipe into the pipe B. The temperature of the superheated
steam passing through the latter into the cylinder is, therefore, reduced in a
measure corresponding to the increased degree of filling.
Another construction for admixing wet steam to the superheated steam is
represented in Figure 6, in which is the inlet for the superheated steam, and the
inlet for the wet steam. The ports I 1, through which the superheated steam
passes into the cylinder, or to one or the other side of the piston respectively, are
opened and closed by the end portions K K' of the piston valve K³. The annular
Fort 12, through which the wet steam may pass over from the aperture into the
valve casing, is controlled by the portion K2 of the piston valve. The extent of
'motion of said portion K 2 of the piston valve is controlled by the regulator
according to the degree of filling of the cylinder. If the degree of filling is but
small, the port 12 will not be opened at all, whereas it is automatically opened if a
greater degree of filling is required. Of course, the piston valve K 3 should be

page_text: connected either to a link motion or to a fly-wheel regulator, so that the extent of
said valve may be made dependent on the degree of filling of the cylinder, as
afore described.
If my invention is to be employed with compound engines, I prefer to let the
excess of heat of the superheated steam be transmitted to the steam present within
the receiver, as has already been mentioned in the preamble. In the form of
construction shown in Figure 7 the highly superheated steam enters first a
casing m that contains a throttle valve n. The latter may be adjusted or regulated
either from hand, or from the regulator, or link motion, or valve distributor of the
engine, or from any movable part the extent of motion of which depends on that
of any of the parts just enumerated. A pipe o branches from the casing m above
the valve n; said pipe o terminates into the lower chamber p 2 of the receiver
P pl.
The righthand side of the receiver is connected with the outlet-piper of the
high-pressure cylinder L, and the lefthand side of the receiver is connected with.
the low pressure cylinder L' by the pipe s. The lower portion of the receiver is
separated from the other or main portion by a horizontal wall or plate w; that
supports a number of upright pipes M of U-like shape. The legs on the lefthand
side are separated from those on the righthand side by means of the partition
wall t, and the steam passing from the pipe r to the pipe s is, therefore, compelled
to wash the pipes M on the whole of their length. The righthand lower chamber p 3
of the receiver is connected with the casing m by a pipe a terminating into said
casing below the valve n. The chambers p2 and p 3 are put into intercommuni-
cation by an aperture t' allowing of the water of condensation collecting within
the chamber p 2 to flow into, and through, the chamber p 3. There is not
constantly a formation of water of condensation, but only on the commencement of
work.
The combined surfaces of the pipes o and M are so measured that the initial
temperature, as required for the lowest degree of filling for the high pressure
cylinder, as well as for the low pressure cylinder, may be attained and maintained
if the throttle valve n is fully opened, so that the greatest portion of the super-
heated steam passes directly through the casing m into the high pressure cylinder,
whereas but a small portion flows to said cylinder on the by-way through the
pipes o M and x. If the degree of filling is increased, there takes place a corre-
sponding reduction of the free section of the casing m by a suitable turning of the
valve n, and a greater portion of the superheated steam is, therefore, caused to
pass through the pipes o M and x, so that the temperature of the superheated
steam L is reduced. The heat removed from the superheated steam has then been
transmitted to the steam present within, or flowing through, the receiver p p', and
that heat is, therefore, utilised within the low pressure cylinder according to the
idea of invention, as afore revealed.
I wish it to be understood, that the regulation of the initial temperature of the
superheated steam by transmitting a certain quantity of the heat of the latter to
a receiver, a feed water heater, or any other means adapted to receive and utilize
heat may be effected in a variety of ways, as will be clear to any expert without
a further detailed explanation. I, therefore, confine myself to expressly mentioning
one mode only consisting in letting the regulator (or any other device controlling
the degree of filling) act upon a valve or other device adapted to intercalate
heating surfaces into the way of the steam, or to cut said surfaces off from said
way, so as to effect thereby the transmission of the excess of heat.
Dated this Bush dan of Tun's 1906
WILHELM SCHMIDT,
By Geo. Thos. Hyde,
1 Broad Street Buildings, London, E.C., Agent for the Applicant.

page_text: CODE DIE DI MUIFICATION.
Improvements in and relating to Methods and Apparatus for
Exhausting the Energy of Superheated Steam in the
Cylinders of all Types of Steam-engines without Detriment
to the same.
I, WILHELM SCHMIDT, of Ballenstedt on the Harz, in the Duchy of Anhalt,
German Empire, Civil 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 object of this invention is to provide means, by the aid of which may be
solved the problem of employing superheated steam in engines of any kind
without detriment to the cylinders, and of fully exhausting the energy of said
steam by doing away with an undue condensation of the same. The problem
proper to be solved is: To be able to employ superheated steam of any attainable
height of temperature in the cylinders of ordinary single and double-acting engines,
as well as in double, triple or multiple expansion engines, and to attain at the same
time a greater energy and a more economical exhaustion than has been attained
with saturated steam up to now. In view of the entire novelty of the idea of
invention, and in order to afford an easier comprehension of the particularity as
well as of the importance of the same, I prefer, first of all, to explain the general
points of view, according to which that which is known in the domain of super-
heated and of saturated steam shall be improved not only with regard to the aim
intended, but also to the means for reaching that aim.
In the very best compound engines at present known the indicated work of steam
in the cylinders amounts in average to only 75% of what should be gained according
to the theoretically possible fall of temperature. Provided for instance, that if
the engine be a condensing engine, the steam may have an absolute tension of
10 atmospheres (about 180° C.), and the temperature in the condenser be about 60° C.,
the fall of temperature will be
180
60120° C.,
but the work of steam utilised therefrom corresponds in the main to a temperature
of about 90° C. only. In most cases however, the exhaustion is considerably lower.
If one succeeded in practically exhausting the theoretical work of steam, i.e. the
whole work of steam without the arising of water of condensation, a fall of
temperature of about 90° C. might be attained with half the tension afore
mentioned, or with an absolute tension of 5 atmospheres respectively because
this tension corresponds to a temperature of about 150° C. The fall of temperature
is thus 150 60 90° C.
The difference between the theoretically possible exhaustion of the work of
steam and the best exhaustion attained up to now is still greater, if steam of a still
higher tension is employed. Assuming a tension of 15 atmospheres, the fall of
temperature is
20060 140° C.
At the best 75%, i.e. 105° C. are exhausted but this fall of temperature (105° C.)
corresponds already to an absolute tension of 7 atmospheres viz. :
TAL
165 60 105° C.

page_text: used in a condensing triple expansion engine cannot do more than can be done by
steam of 7 atmospheres, in a condensing double expansion engine, if one succeeds
of coming near to the theoretically possible work of steam. Under this
supposition the energy of saturated steam of a tension of 25 atmospheres (the
fall of temperature of which requires already a compound engine with not less
than 4 cylinders) may, from an economical point of view, well be opposed to the
energy of steam having an absolute tension of 11 atmospheres, and acting in a
double cylinder compound engine.
The reasons for that imperfect exhaustion of the energy of the steam are the
great losses of heat caused by the condensation of steam within the cylinder.
The means for reducing said losses (furnishing the cylinders with steam jackets;
employing the steam three or four times in engines with three or four cylinders,
and beating the receivers) have practically come to a limit already.
Such and other considerations and researches, and also the certainty that a
further material development of the steam engine cannot possibly be attained on
the. way chosen hitherto, led me, many years back, to trials with superheated
steam, although such use of steam had at that time been given up in consequence
of the great difficulties connected with the generation, employment, and exhaustion
of the said steam. The progresses resulting from said trials reside mainly in the
means and methods for the generation of highly superheated steam, and for the
non-detrimental application of the latter in single-acting engines. The limit of
what has been attained by me up to the present in the domain in question is the
compound engine and boiler for superheated steam described by Professor Schröter
of Munich in Volume 39 (1895) of the "Zeitschrift des Vereins Deutscher
Ingenieure" (Journal of the Association of German Engineers).
The highest aim now to be reached is to obtain in a simple manner a practically
perfect and non-detrimental exhaustion of the energy of highly superheated steam
of a high tension in the working cylinders of double-acting double-expansion and
especially triple-expansion engines. To reach that aim there is, however, requisite
a particular regulation of the temperature of the superheated steam on entering
the cylinder. The manner of said regulation may be dependent on the particular
type of engine, but is in any case dependent on the degree of filling of the cylinder
or cylinders of that engine with the superheated steam. The invention proper
resides, therefore, in methods and means that affords an advantageous or non-
detrimental application of highly superheated steam, and an exhaustion of the
high energy of the latter, in all types of engines, especially double-acting engines
and multiple expansion condensing engines, by regulating in a particular way the
temperature of the superheated steam on entering the cylinder of the engine,
said regulation being made dependent on the degree of filling of that
cylinder, and being controlled in such a manner that the expanding steam
remains dry whilst performing the greatest part of the work possible during
one stroke of the piston, the rest of said work being performed by expauding
saturated steam.
To show more clearly the significance of the above manner of regulating the
temperature of the superheated steam (on entering the cylinder) according to
the degree of filling, I will first give in the following some examples therefore the
figures occurring in the latter are determined so as to yield a perfect dryness of
the steam during the first half of the path of the piston.
Saturated steam having an absolute tension of 10 atmospheres (on entering the
cylinder) suffers a decrease of tension down to 6 atmospheres whilst the piston
makes half its way provided the degree of filling amounts to 30%. The fall of
temperature is thus about:

page_text: fourfold amount of the fall of temperature. The temperature of steam of an
absolute tension of 10 atmospheres (on entering the cylinder) is thus to be (for a
degree of filling of 30 %):
If the degree of filling is 20% only, the tension of the steam
4 atmospheres during the first half of the path of the pi
therefrom a fall of temperature of about
180 (446)
= = 364° C.
The above few examples distinctly show the importance of regulating the
temperature of the superheated steam (on entering the cylinder) according to
the degree of filling. Said examples show, further, that slightly below a degree
of filling of 15% there must practically lie the lowest limit for the exhaustion of
highly superheated steam, because materially higher temperatures cannot con-
tinuously be attained. The temperature of the steam (on entering the cylinder)
must, however, be materially higher, if the degree of filling amounts to less than
15%, and if a condensation of steam in the first half of the cylinder (with regard
to the direction of motion of the piston) shall be avoided.
In the theoretical working diagram represented in Figure 1 of the drawing sent
in with Provisional Application (this figure is duly enumerated in the short
description of the figure hereinafter following, but must be referred to now on
account of the deductions to be drawn therefrom) the dotted line ab represents
the specific volumes of the steam. In reality, the effect remains widely behind said
ideal line a-b in consequence of the abundant condensation of saturated steam
that occurs in the cylinder mainly instantly after the inlet as well as during the
first period of expansion. The real effect yielded by the very best compound
engines may, perhaps, be indicated by the dot-and-dash-line e-f. The loss caused
by the unavoidable condensation of steam during the first half of the way of the
piston may be represented by the curved quadrangle a-b-e-f-e. The curved
triangle a-d--indicates the increase in the volume of the steam by the super-
heating, and the full line d-b represents the line of limit for the real effect of the
steam if this latter remains superheated to the middle of the path of the piston.
The point of intersection 6 of the lines a-b and d-b is the so-called "point of
saturation." The work performed by dry steam is finished at said point b; the
superheated steam turns into saturated steam, and the rest of the work is performed
by expanding saturated steam according to the established physical law for saturated
steam.

page_text: It will be found on a closer examination of the diagram in question, that the
work to be performed by expansion during the second half of the way or stroke of
the piston is but very slight with regard to the work already performed by the
full pressure as well as by the expansion of the superheated steam during the first
half of the said stroke or way and, further that even said rest of work will be
without a material condensation of steam because the saturated steam in the second
half of the cylinder (with regard to the direction of the piston) is strongly heated
by the comparatively great radiation of heat from the surfaces that have been in
contact with the superheated steam in the first half of said cylinder. The water
of condensation resulting from the expansion of the saturated steam during the
second half of the way of the piston amounts to about 4% only. Such a low
percentage of water of condensation is without importance in view of the whole
amount of work done by the steam during one stroke of the piston but said low
percentage is, on the other hand, of great importance for the preservation of the
sliding surfaces of the cylinder and other parts. This shows distinctly, that by
regulating the temperature of superheated steam according to the degree of filling
of the cylinder the rising of water of condensation, and the bad influences resulting
therefrom may effectively be done away with, or that, in other words, the
theoretical amount of energy of the steam may be fully exhausted. It will later
on be shown that this full exhaustion may be attained also if the degree of super-
heating is but very low.
If the principle above revealed is employed with double-acting steam-engines,
there may be attained some other advantages besides those afore stated. For
instance, by elongating the cylinder as well as the piston in a certain measure, the
drawbacks generally resulting from the application of superheated steam, or of
steam of a high tension (great consumption of lubricants, and endangering of the
sliding-surfaces of the cylinder and other parts) are entirely done away with.
The Figure 2 shows two piston-diagrams (taking one into the other) for super-
heated steam of an absolute tension of 12 atmospheres, and of an inlet temperature
of about 330° C.; this temperature must be chosen slightly higher than the
theoretical temperature in view of the losses caused by the walls of the cylinder,
of the high pressure cylinder of a double expansion engine working with a degree
of filling of 25 %. The cylinder and its piston are represented below said diagram.
If the length of the piston is equal to half the stroke or way of said piston and if
the packing rings are arranged in the middle of said piston, there then results the
following:
The tension of said steam gets reduced to 6 atmospheres till half the stroke of
the piston; the steam has then turned into saturated steam, and possesses on the
commencement of the second half of the stroke of the piston a temperature of
about 160° C.; that temperature results into an end-temperature of 128° C., if the
counterpressure at the end of the way of the piston amounts to 2 atmospheres.
The mediate temperature of the steam in the second half of the piston is thus

page_text: appearing in the above formula I call attention to the fact that till to the com-
mencement of the period of expansion the steam has cooled by 30° C.), and to
128° C. for the stroke of the piston in the other direction, the mediate temperature
for a piston-stroke corresponding to the line a¹ b' is
This piston-stroke is a quarter of the whole stroke in one direction, and a quarter
of the whole in the other direction, so that the piston performs the half of a
stroke at a mediate temperature of 179° C. It results from this, that the mediate
temperature of the walls of the cylinder on a whole stroke of the piston is:
These examples show convincingly, that by correctly regulating the inlet
temperature according to any degree of filling, and by correspondingly elongating
the piston, all difficulties as to the preservation of the sliding surfaces of the
cylinder and other parts are completely done away with; or, in other words, that
even with the application of a high superheating of the steam all hurtful influences
may be fully avoided.
If the filling (of the cylinder with steam) is but small, the mediate temperature
on the way of the piston in one direction, and on the way of the piston in the
other direction, is still smaller than that above stated although, according to
the above examples the inlet temperature increases strongly if the degree of filling
decreases. Under all circumstances, therefore, the steam keeps its natural property
of being able to serve as a lubricant within the zone for the expansion of saturated
steam, and it is hereby proved that even a greater consumption of lubricants
cannot take place. If space is wanting, or if one is satisfied with the steam
remaining dry for 40% only of the stroke of the piston, the length of the piston
may be only 33% of said stroke, without attaining a mediate temperature of too
high a degree.
It is distinctly to be seen from what has been explained up to this point that the
highest exhaustion of the energy of highly superheated steam may be attained
whilst keeping on a low mediate temperature of the walls of the cylinder; that
low mediate temperature may be below that for saturated steam of the same
tension if steam jackets are employed.
If the highly superheated steam is to be used in a compound engine, the
regulation of the inlet temperature of that steam may well be effected by
transmitting the excess of heat of the steam for the high pressure cylinder to the
steam contained within the receiver, so as to superheat said latter steam, in such a
manner, that the course of the work, which the steam performs within the low
pressure cylinder is similar to the course of the work which the live-steam
performs within the high pressure cylinder. If the inlet temperature is regulated
in this way, that is to say, if the heat of the superheated steam is distributed upon
several cylinders, the fall of temperature of steam having an absolute tension of
12 atmospheres may be exhausted without the arising of appreciable quantities
of water of condensation in a compound engine.with but two cylinders, whereas
without the regulation in question, and with the application of saturated steam, a
compound engine with three cylinders is requisite, even if the degree of exhaustion
is assumed to be 75% only of the theoretical amount of energy. Moreover the
inlet-temperature of the superheated steam may be so low as would have been
thought impossible previous to the disclosure of the present invention. The
economical effect in the example last given is equal to that which could be attained
in a compound engine having four cylinders, and working with a steam of a tension

page_text: of 25 atmospheres, if the distribution of the steam is effected in the manner
formerly employed.
That extraordinary effect resides in the former method of distributing the steam
(saturated steam) allowing of a utilization of a fall of temperature on only 40° C.
in one cylinder, whereas on regulating the inlet temperature according to this
invention a fall of temperature of 70°, and even more, may well be utilized, the
steam being fully exhausted and the inlet temperatures being not too high.
The whole fall of temperature of steam having an absolute tension of 25
atmospheres is
225 60165° C.
or about 41° C., for each of the four cylinders. The fall of temperature for the
first cylinder is, therefore, from 225 down to 184° C., which corresponds to a
reduction in tension from 25 down to 11 atmospheres. The mediate temperature
of the walls of the cylinder is then about 198° C., whereas the mediate tempera-
ture of the walls of the cylinder of a double expansion engine for the use of
superheated steam amounts to 147.5° C. only in those parts of the cylinder that
are touched by the packing rims of the piston, the degree of filling being assumed
to be 25%.
It may be mentioned at this place of the specification, that another advantage of
the novel arrangement resides in the differences of tension being lower with
superheated steam than with ordinary saturated steam, which permits of the
packing rims of the piston being pressed against the cylinder with a lower force
than otherwise requisite. In the examples afore given the difference of tension
is 25 1114 atmospheres in one case and 12-2.5 = 9.5 atmospheres in the
other case.
The special advantage (concerning the reduction of the differences of tension)
afore mentioned is still greater, if the novel method of regulating the temperature
of the superheated steam is applied to steam of a tension of about 20 or more
atmospheres, in that in such a case a triple expansion compound engine may
perform more than a four-cylinder compound engine working with saturated
steam. Whilst the fall of temperature in the cylinders of a double expansion
engine working with steam of an absolute tension of 12 atmospheres amounts to
still 64° C., the fall of temperature for each cylinder of a triple expansion engine
working with steam of an absolute tension of 12 atmospheres amounts to no more
than 51° C. The inlet temperature of the steam amounts to 330° C., if a double
expansion engine is driven with a degree of filling of 25% by steam having an
absolute tension of 12 atmospheres; if, however, steam having a tension of
20 atmospheres is employed in a triple expansion engine, the fall of temperature
amounts to only 300° C."
It is at present possible to generate superheated steam having a temperature of
380° C., and therefore, in the first of the two cases last mentioned there may be
utilized 50° for superheating the steam within the receiver, whereas in the second
case even 80° C. may be utilized in that way.
With triple expansion engines that are subjected to a strongly varying strain,
and in which greater degrees of filling (about from 33-40%) especially for the high
pressure cylinder are used, there may be employed still lower initial temperatures.
than are at disposal for regulating the degree of superheating by distributing the
beat of the steam in such quantities that even with a very great variation in the
strain of the engine a correspondingly varying superheating of the steam within
the receiver. may well be effected. Very much the same circumstances apply to
large engines with an unvarying degree of filling. If a big triple expansion
marine engine is to be driven by superheated steam, the attendance of the
superheaters for that steam is difficult, in view of the comparatively great number
of the same, as resulting from the comparatively great number of boilers necessary
for producing the steam to be superheated.
By employing in such a case suitably greater degrees of filling, one may get

page_text: (without an appreciable loss of energy) so low an initial degree of temperature
that the generation of the superheated steam having that low degree may in any
case be securely attained. If, perhaps, in certain cases the excess of heat of the
superheated live steam should not be sufficient for superheating the steam within
the receiver in a suitable degree, than the correct initial temperature of the steam
for the next following cylinder may easily be attained by providing a special
superheater for the receiver. It is, however, to be preferred to let the superheated
live-steam have such an initial temperature, that the steam within the receiver may
well be sufficiently superheated.
In general, on producing superheated steam, the degree of superheating should
he chosen as high as attainable from the superheater employed, without endangering
the latter. The superheated steam will, therefore, generally possess a temperature
of from 350-380° C.; such temperatures are fully sufficient for enabling the
steam to remain dry down to half the way of the piston, even if the degree of
filling used is very low, for instance 15%. If the degree of filling is greater,
there then exists an excess of heat that may be utilized in a great variety of ways.
If instead of a triple or double expansion engine a single expansion engine is
employed, the regulation of the initial temperature (according to the idea of this
invention) may be effected in another way, for instance by mixing the superheated
steam with wet steam, in varying degrees, corresponding to the varying degrees of
filling of the respective engine; but the excess of heat existing at a given time
may if desired be transmitted to feed water or be utilized and removed from the
steam, in any other suitable way. The means for effecting the regulation in one or
the other manners may be adapted to be operated either from hand or in an
automatic way, as may be found best suited for the particular case.
In locomotive engines, for instance, the initial temperature may be regulated (in
a sense according to the idea of invention) from hand by operating the regulating
device for the superheater proper in such a manner as to adjust said regulating
device in accordance with the position of the distributing lever of the locomotive
engine. In other words, said regulation and adjustment is to be effected in such a
way, that the superheated steam remains dry down to half the stroke or way of
the piston, or does not prior thereto turn into saturated steam respectively.
The same mode of operation may be used with many other types of engine, in
which either the variation of strain is but very slight, or in which an equally great
degree of filling is maintained for a comparatively long time. The best mode of
operation will however be in any case letting the regulation of the temperature of
the steam be effected by the steam distributing device of the respective engine
supposing the latter be an expansion engine, and I think I may mention at this
place that said steam distributing devices are supplemented or completed by my
present. invention in quite a remarkable degree. The value of said devices is
greatly increased by the latter being made able to regulate automatically the initial
temperature of the superheated steam according to the varying degrees of filling
of the respective engine. Anyhow, to effect that automatic regulation there need
not indispensably be employed the steam distributing device proper, but any other
part, the position of which depends on said device.
In some cases the automatic regulation may be effected by making use of the
variations of pressure of the steam within the main inlet pipe, in that for instance
said variations are employed for operating an automatic valve that controls the
admission of wet steam to the superheated steam, as already afore mentioned.
In order to make my invention more clear, I refer to the drawings sent in with
Provisional Application, in which similar letters denote similar parts throughout
the different views, and in which:
Figure 1 shows a diagram that has already been referred to in the above
preamble.
Figure 2 shows also a diagram, together with the cylinder and piston of a steam
engine, the said cylinder being in longitudinal section. Also these parts have
already been hereinbefore referred to.

page_text: Figure 3 shows a vertical section thrigh a generator for sup
together with some parts of an engine inten lel to be driven by such steam, and
together with the mechanisms for regulating the inlet temperature of the
superheated steam according to the principle of the present invention.
Figure 4 is an outer view of the steam generator shown in Figure 3 in which the
mechanisms for effecting the said regulation differ from that shown in the said
figure.
Figure 5 is a vertical longitudinal section through the valve i of Figure 4, drawn
on a larger scale.
Figure 6 is a longitudinal section through particular construction of a steam
distributing valve, and through the adjacent portions of the cylinder having that.
valve, and
a
Figure 7 is a section through the receiver of a compound engine, the cylinders
of the latter and the steam pipes between said cylinders and the receiver being
also in section.
Referring to Figure 3 h is a pipe that connects the steam space of the boiler
proper A with the steam inlet pipe B for the cylinder C. The pipe B is connecte: 1
to one end of the superheater D, the other end of which is connected with the
steam space afore mentioned by means of the pipe E. The pipe is furnished
with a valve g that is connected to the lever F of the regulator G by means of the
rod H. Supposing the regulator to act in such a manner as to cause in its return
an increase of the degree of filling, the valve g will be opened in a corresponding
degree, so as to allow of a certain quantity of wet steam to pass over into the
pipe B, and to mix with the superheated steam flowing through said pipe. The
temperature of the superheated steam is, therefore, reduced in a measure
corresponding to the increased degree of filling. If, on the other hand, the degree
of filling is reduced, the regulator acts upon the valve g in the reverse way, i.e.
closes said valve either nearly or wholly. In the form of construction shown in
Figures 4 & 5 the variations of pressure caused within the pipes B and h by the
influence of the regulator in question, are made use of. For this purpose the pipe h
is furnished with an automatic valve i, the valve proper of which is suspended
by a spring. The tension or strain of said spring is so chosen that the pressure
of the wet steam (within the boiler proper A) is not sufficient to open the valve
proper. If, however, the pressure within the pipe B gets reduced in consequence
of a sudden increase in the degree of filling of the cylinder C, the valve proper i¹
is raised by the wet steam, and a certain quantity of the latter passes through the
pipe h into the pipe B. The temperature of the superheated steam passing through
the latter into the cylinder is, therefore, reduced in a measure corresponding to the
increased degree of filling.
Another construction for admixing wet steam to the superheated steam is
represented in Figure 6, in which k is the inlet for the superheated steam, and the
inlet for the wet steam. The ports J J', through which the superheated steam
passes into the cylinder, or to one or the other side of the piston respectively are
opened and closed by the end portions K K₁ of the piston valve K 3. The
annular port J 2 through which the wet steam may pass over from the aperture
into the valve casing, is controlled by the portion K2 of the piston valve. The
extent of motion of said portion K2 of the piston valve is controlled by the
regulator according to the degree of filling of the cylinder. If the degree of
filling is but small, the port J2 will not be opened at all, whereas it is automatically
opened if a greater degree of filling is required. Of course, the piston valve K 3
should be connected either to a link motion or to a fly-wheel regulator, so that the
extent of said valve may be made dependent on the degree of filling of the cylinder,
as afore described.
If my invention is to be employed with compound engines I prefer to let the
excess of heat of the superheated steam to be transmitted to the steam present.
within the receiver, as has already been mentioned in the preamble. In the form
of construction shown in Figure 7 the highly superheated steam enters first' a
C

page_text: casing m that contains a throttle valve n. The latter may be adjusted or regulated
either from hand, or from the regulator, or liuk motion or valve distributor of the
engine, or from any movable part the extent of motion of which depends on that
of any of the parts just enumerated. A pipe o branches from the casing m above
the valve n; said pipe o terminates into the lower chamber p2 of the receiver pp'.
The righthand side of the receiver is connected with the outlet pipe r of the
high-pressure cylinder.L, and the lefthan I side of the receiver is connected with
the low pressure cylinder L' by the pipe s. The lower portion of the receiver is
separated from the other or main portion by a horizontal wall or plate w, that
supports a number of upright pipes M of U-like shape. The legs on the lefthand
side are separated from those on the righthand side by means of the partition-wall t,
and the steam passing from the pipe r to the pipe s is therefore, compelled to clean
the pipes M for the whole of their length. The righthand lower chamber p 3 of
the receiver is connected with the casing m by a pipe e terminating into said casing
below the valve n. The chambers p 2 and p 3 are put into intercommunication by
an aperture t¹ allowing of the water of condensation collecting within the chamber p 2
to flow into, and through, the chamber p 3. There is not constantly a formation of
water of condensation, but only on the commencement of work.
The combined surfaces of the pipes o and M are so measured that the initial
temperature as required for the lowest degree of filling for the high pressure
cylinder as well as for the low pressure cylinder, may be attained and maintained
if the throttle valve n is fully opened, so that the greatest portion of the superheated
steam passes directly through the casing m into the high pressure cylinder, whereas
but a small portion Hows to said cylinder on the by-way through the pipes o M
and. If the degree of filling is increased there takes place a corresponding
reduction of the free section of the casing m by a suitable turning of the valve n,
and a greater portion of the superheated steam is, therefore, caused to pass through
the pipes o M and x, so that the temperature of the superheated steam Lis reduced.
The heat removed from the superheated steam has then been transmitted to the
steam present within, or flowing through, the receiver p p', and that heat is,
therefore, utilised within the low pressure cylinder according to the idea of invention,
as afore revealed.
I wish it to be understood that the regulation of the initial temperature of the
superheated steam by transmitting a certain quantity of the heat of the latter to a
receiver, a feed water heater, or any other means adapted to receive and utilise
beat may be effected in a variety of ways, as will be clear to any expert without a
further detailed explanation. 1, therefore, confine myself to expressly mentioning
one mode only consisting in letting the regulator (or any other device controlling
the degree of filling) act upon a valve or other device adapted to intercalate
heating surfaces into the way of the steam, or to cut said surfaces off from said
way so as to effect thereby the transmission of the excess of heat.
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
1. The method of employing superheated steam in, the cylinders of all types of
steam-engines, and of exhausting the energy of such steam, consisting in regulating
the temperature of the superheated steam according to the degree of filling of the
cylinder or cylinders of the respective engine, in such a manner, that the greatest
admissible part of the stroke on which the expanding steam can be allowed to
remain dry with respect to the relative proportions of the respective cylinder may
"have a uniform length at varying degrees of filling, substantially and for the
purpose as described.
2. An arrangement for executing the method claimed under Claim 1, (especially
for steam engines with a temporarily constant degree of filling, such as locomotive
engines and similar ones), consisting in the superheater itself being furnished with
a regulator for the temperature of the superheated steam, said regulator being

page_text: adapted to be adjusted either by hand or compulsorily, by the governor or the.
steam-distributing device, or automatically by differences of pressure or temperature,.
substantially and for the purpose as described.
3. An arrangement for automatically executing the method claimed under Claim 1
(especially for single expansion steam engines), consisting of a regulator the
adjustment of which is dependent on the governor or the steam-distributing device.
of the respective engine, or of a valve adapted to be actuated by differences of
pressure; said regulator or valve being so arranged as to control the admixture of
steam of a lower temperature to the superheated steam, substantially and for the.
purpose as described."
4. An arrangement for executing the method claimed under Claim 1, consisting
of a regulating device constructed according to Claim 2 & 3, and being adapted to
effect the regulation of the inlet temperature of the superheated steam by letting
the excess of heat of the latter be transmitted to feed-water, or removed in any
other useful manner.
5. A form of execution of the method claimed under Claim 1 (especially for
double or multiple-expansion-engines) consisting in effecting the regulation by
transmitting the excess of heat of the superheated live-steam to the receiver-steam,.
for the purpose as described.
6. An arrangement for automatically executing the method claimed under Claim 5,.
consisting in the combination of the receiver with a superheater adapted to super-
heat the receiver-steam by means of a current of superheated steam branching off
the live steam-conduit, the temperature of the superheated live steam passing
through said conduit into the high pressure-cylinder being reduced by the returning:
branch of steam, substantially as shown in Figure 7.
Deted this 9th dor of March 1807
WILHELM SCHMIDT,.
By Geo. Thos. Hyde,
1, Broad Street Buildings, London, E.C., Agent for the Applicant..