Improvements in Steam-motors.
Year: 1887

page_text: Date of Application, 21st Feb., 1887.
Specification Accepted, 22nd Mar., 1887
COMPLETE SPECIFICATION.
Improvements in Steam-motors.
I, WILHELM SCHMIDT, of 48 Leonhardstrasse at Brunswick in the German Empire,
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 improvements in steam-motors described hereinafter relate both to the arrange-
ment of the steam-boiler and the cylinder and to the governor which is placed between
these two component parts of the steam-motor. The object of these improvements
is to construct a steam-motor, which owing to its simple make and the easiness with
which it can be worked is peculiarly well adapted for small establishments and
workshops.
In order to make it suitable for the purpose just mentioned the steam-motor must not
only be simple in construction and easy to drive, but it must also work economically,
uniformly and steadily. All these requirements are fulfilled by the combination
and arrangement of the steam-boiler, steam-cylinder and governor in the steam-motor
now to be described. By this new arrangement of the steam-boiler a quick and
practical generation of steam is attained; the distribution of steam is carried out most
practically by the governor, and owing to the peculiar arrangement of the steam-
cylinder the generated steam is utilised in a most economical way.
Fig. 1 shows a cross-section of the steam-motor; Fig. 2 represents a partial cross-
section and side-view of it, and Figs. 3, 4 and 5 illustrate detailed constructions of the
governor on an enlarged scale.
The characteristic peculiarity of this new arrangement of the steam-boiler is as
follows: a steam-boiler c that is heated direct by means of a fire-box A is combined
and connected with a second steam-boiler in such a way, that the steam generated in
the first named boiler c plays centrically round the jacket of the second boiler b, and

page_text: thereby heats it indirectly. It must however be remarked that the steam coming
from the direct heated boiler c plays round the jacket-surface only, but does not touch
the ends of the indirect heated boiler b. Owing to their not being touched by the
steam the ends are easily accessible at any time, and incrustation can be removed from
the boiler through thein whenever required. Accessibility to the boiler-ends and
through them to the boiler itself is indispensably necessary to make this arrangement
practically useful, for this indirect heated boiler has constantly and alone to supply
the steam engine with the steam the latter requires. The feed-water is continually led
into this indirect heated boiler and the sediments are deposited in it only. Tho
volume of water in the outer and direct heated boiler c always remains the same;
when converted into steam this water plays round the inner boiler b, condenses on the
latter and being thus re-converted into water runs back into that part of the boiler
that is heated by fire, and in course of time is again converted into steam. The water
in this boiler is continually describing a circular course and the steam that is generated
in it for the purpose mentioned above may be of a very high pressure and will there
fore exercise a very energetic heating effect on the inner boiler by reason of its high
temperature.
The construction of the steam-boiler is as follows:
The direct heated boiler c, which consists in an unbroken or continuous system of
tubes (serpentine-pipe) is located in the fire-box A. The two ends c¹of the
serpentine-pipe c project out of the fire-box A and terminate at o¹ and o² in the
jacket m. The actual steam-boiler is fixed and packed inside this jacket m and
consists in a smooth cylindrical tube, which is encircled in its whole length by the
jacket m. The steam coming out of the tubular-boiler c passes through the vessel
(jacket) m and plays round the steam-boiler b. The water contained in the latter is
heated by this steam, which condenses and runs back as water through into the
tubular-boiler c. The two vessels m and b can of course be arranged in a horizontal
position. The actual generator of the working steam & is packed at both ends in the
jacket m. The boiler is packed at its ends (either at pipe b itself, or, as represented
in the design, at the projecting pipe ends of m) by means of the lid and strap d, which
can be easily removed and thus allow the sealing of the boiler b to be carried out most
conveniently. A cylinder is suspended above the common water-level in the boiler b
and leaves a very narrow space on both sides between itself and the sides of b and
therefore a very narrow passage also for the steam to pass through when ascending.
Owing to this the steam is dried in its ascent and passes as dry steam through the
opening n and the pipe connected with the latter into the hollow support s. The
water-gauge w and the steam-piper which latter serves to feed the steam-engine, are
both fixed to the hollow-support s. In addition to this the hollow support s is con-
nected by pipe n' with the lower end of the inner-boiler b, so that the water led by the
feed-pipe from the water-pump p can enter the boiler b.
The characteristic peculiarities of the steam-engine that is fed by this boiler b con-
sist in the arrangement of the steam-cylinder and the using of a special governor
placed between the cylinder and the boiler.
The arrangement of the cylinder is such, that the lower part of it or rather the
bottom is suspended in the fire-box and forms a part of the top of the fire-box or stoke-
hole. The upper part of the cylinder is on the other hand protected against the
influence of the fire by means of a hollow space f, which is left round the cylinder and
forms the remaining part of the fire-box top.
The advantages that are offered by this arrangement of the cylinder, that is to say,
by this suspending of the cylinder in the stoke-hole top and by the leaving of a space
round the upper part of it, are as follows: Firstly the cylinder is always kept heated
by this means and as the steam comes in contact with hot surfaces it does not cool;
secondly, the heat of the fire is prevented from exercising any injurious influence on
the steam-motor, by means of the hollow top or cover of the cylinder; thirdly, the
upper part of the cylinder is constantly cooled by the steam puffed out of the cylinder
because this steam rushes into this hollow space f and therefore a continuous fresh

page_text: supply is given constantly to the jacket of the cylinder. The steam piston 7 which
is moved alternately in a heated and alternately in a cooled part of the cylinder is
likewise intermittingly cooled and by this means the packing is preserved. The
exhausting steam of the engine escape through the opening k of the stoke-hole
passing the space f.
The regulating contrivance of the steam-motor still remains to be described. Fig. 1
shows a cross-section of it when attached to the motor, and Fig. 3 illustrates the
regulator in detail.
As may be seen in Fig. 1 this regulating contrivance is fixed between the cylinder
and the steam-feed pipe r, and consists (as seen in detail in Fig. 3) materially in a
piston-slide g. This piston-slide is operated (influenced in its motions) by the pump
piston p which is worked by the machine. For this purpose the pump plunger pl
pumps and compresses the steam of the boiler, and conducts the compressed steam
through the pipe or opening a¹ and the valve e beneath or above the piston slide g, see
Figs. 1 and 3.
じ
In Fig. 1 this pump is shown attached direct to the combined steam-distributor t
(slide) and to the water-pump p and is set in motion by the eccentric v³, Fig. 1.
It must be considered as an innovation of this arrangement, that the steam-pump,
which moves the piston-slide by compressing part of the boiler-steam, is placed in this
case direct in the steam-conduit (steam feed-pipe) for the slide-valve case (see Fig. 3),
and that consequently steam of high pressure is conducted to the steam-pump p² and
compressed by it. By using compressed steam in the pump even a small compression
of steam is sufficient to move the piston-slide g and to regulate the working of the.
motor; but this regulating of the motor is also effected hereby without using stuffing-
boxes and other things calculated to make the regulating more difficult.
Neither the pump-plunger nor yet the piston-slide 9 need be made to work
perfectly tight in their cylinders in this case; on the contrary, the effect of the
present innovation is directly dependent on the untightness of the pump-plunger in its
cylinder.
The way, in which the governor works, is as follows: (Fig. 3) :
When in its highest position, the pump-plunger pl allows boiler-steam to enter the
pump-space y through the lateral-channel a, and on its descending this steam is com-
pressed in the pump-cylinder y. As the pump-plunger pl is not perfectly tight part
of the compressed steam rushes back past and round the plunger p¹, and not before
the motion of the plunger p¹ has exceeded a certain velocity does a sufficient over-
pressure arise in the steam-cylindery. As soon as there is an over-pressure of steam
in the cylinder the shut-off valve is opened. But this valve is firmly connected
with the piston-slide g and as soon as it is opened this over pressure of steam operates
on a large surface (the surface of the piston-slide) and forces the piston-slide to move
and to shut the steam-openings o, which lead into the slide-box P.
The boiler-steam is then completely shut off from the slide-box P and that quantity
of steam only that is contained in the slide-box at the time can work as a generator of
power on the piston of the steam-cylinder; the result of this is that as the quantity of
steam in the slide-box is small, a great expansion of steam and therefore a decrease in
the working power of the motor ensues. In other words the working of the motor is
regulated.
It is evident that this regulating can ensue only when the pump-plunger descends
and is therefore for one side of the cylinder only. On the other side of the cylinder
the steam enters full and perfectly unimpeded by the pump-plunger. In order to
remove this drawback in motors all that is required is to arrange the piston-slide g in
such a way that it is independent of the valve v of the pump-cylinder. This construc-
tion is represented in two modifications in Figs. 4 and 5.
In Fig. 4 v is the shut-off valve of the pump-cylinder; is closed by a small spring.
When the pump descends and when the steam is sufficiently compressed in the pump-
cylinder, the over-pressure (of steam) escapes through the valve v. But as soon as the
over-pressure of steam in the pump-cylinder has ceased owing to its being conducted

page_text: off to the space v¹, the valve vis closed again; the two spaces y and are then
separated again immediately. The overflowed steam in y presses the piston-slide g
downwards and the feed openings o of the piston-slide g are made smaller hereby. By
this means the regulating of the steam for both sides of the cylinder is attained, for
the piston-slide must be tight enough to keep the quantity of steam in the space v till
the pump-plunger p₁ descends again. The position of the piston-slide is therefore
regulated according to the velocity of the motor.
In the modification shown in Fig. 5 this shut-off valve is dispensed with entirely
and is replaced by a narrow opening between the two spaces y and v¹. This
opening has the same effect, as above described; it also causes a greater pressure
in the space v', when the pump-plunger p¹ descends.
The way, in which this modification works, must be explained more detailed.
The pump-plunger plis descending and in doing so it compresses the steam that has
rushed in at the side through the channel a. Let it be presumed that the steam of the
boiler has a pressure of 6 atm. In compressing this steam in the pump-cylinder ya
certain amount of it will escape past and round the plunger pl. If the motion of the
plunger p¹ exceeds the velocity desired, the surplus steam will pass through the
opening into the space v¹. This occurs immediately after the compressing begins, and
the piston-slide moves therefore a short distance downwards and regulates the entrance
of steam. As the inlet opening a¹ is but small a lower pressure will prevail in the
space than in the pump cylinder y, for a large amount of steam cannot pass through
the opening when the motion of the pump is very quick.
When the plunger pl ascends again this surplus of pressure in the steam-space will
have the effect that before the ascent of the pump-plunger is concluded the pressure in
the pump-cylinder y will equal that of the boiler, but in space va higher pressure
will still prevail. The time the steam rushes out of the steam-space y into the space v
is longer than the time given it to rush out again.
Let it be presumed for instance that the boiler-pressure is 5 atm., then during the
whole descent of the plunger a higher pressure will prevail in the pump-cylinder y.
This pressure will always rise and can for instance through the opening raise the
pressure in space to 5 atm. Towards the end of the downward motion of the
pump-plunger p¹ there will be a pressure of about 7 atm. in the pump-cylinder y.
During the first part of the ascent of the pump-plunger the pressure remains greater in
the space y than in v¹ and steam continues to rush from steam-space y to space v¹. In
the second part of the ascent the pressure decreases and when the middle position is
reached the pressure is the same as that in the space v¹. It is therefore only at the
conclusion of the ascent that the steam rushes back out of space v¹ to the pump-
cylinder y. If we consider that this over-pressure in space v¹ over that in the pump-
cylinder y is very
small (only atm.) then it is accountable that the short time allowed
the steam to rush back out of v¹ will not suffice to allow the pressure in the space to
sink to 5 atm. According to the velocity of the pump-plunger there will always be a
certain over-pressure in space v¹, which will rise as the velocity increases and sink as
it decreases, and this rising and falling of the over-pressure affects the position of the
piston-slide 9. It must be remarked, that, owing to the considerable surface of the
piston-slide itself, small fluctuations in this over-pressure will cause a great alteration
in the dosition of the piston-slide, and therefore the sensibility of this governor is very
great.
In all three modifications the weighing of the piston-slide can be regulated by
displacement of the spring f1, so that even while the machine is working the velocity
can be regulated as may be desirable.
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.) In steam-motors the application of two steam-boiler-pipes mb fixed one inside
the other but forming two separate spaces, of which the inner space is provided with
the side inlet and outlet openings n n for the feed-water and the steam, whereas the

page_text: outer space is connected on both sides with a continuous direct heated tube system c,
for the combined purposes of generating steam indirectly and of cleaning the inner
pipe easily of incrustation.
2.) The inserting of a central upper piece / in the inner boiler pipe 6 for the purpose
of forming a narrow annular space with a view to dry the ascending steam.
3.) A steam-cylinder, the lower end of which is suspended in the fire box, in com-
bination with a hollow space f which surrounds the upper part of the steam-cylinder,
shuts of the fire-box and communicates with the steam-cylinder at one side and with
the channel at the other side for the combined purposes of warming the steam-
cylinder and of cooling the upper part of the cylinder and the motor which is arranged
above the fire-box.
yo
4.) The application of a piston-slide arranged in the steam feed pipe leading to
the cylinder in connection with a pump p¹ which compresses boiler steam and the
delivery pipe of which leads under the piston of the piston-slide g and moves the latter
thereby, for the purpose of regulating the working of the machine by shutting-off the
steam that drives the machine.
10:1
1
WILHELM SCHMIDT.
By A. Kuhnt & R. Deissler,
Attorneys.