IMPROVEMENTS IN GENERATORS OF STEAM
Year: 1884

page_text: I, WILHELM SCHMIDT of 70 Alexanderstrasse Berlin in the German Empire,
Engineer, do hereby declare the nature of said Invention for IMPROVEMENTS IN
GENERATORS OF STEAM to be as follows:-
My invention relates to that class of steam generators which consist of a
continuous system of tubes.
Hitherto steam generators consisting of continuous coils of pipes have been
supplied with water by forcing the latter into the lowest part of the coil, so as to
produce a gradual upward motion of the same.
According to my invention I introduce the feed water at the top of the system
of coils or inclined pipes, so that the lowest parts of the system of tubes or the
lowest convolutions of the coil contain steam, while the upper contain water, and
the steam outlet is situated at the bottom of the system.
In order to protect the lowest part of the coil from burning, I place between the
base of the vertical coil and the fire space a ring of fire proof bricks, with conical
opening, to which ring may be added a short cylindrical shield of metal situated
inside the space enclosed by the lowest parts of the coil.
I also control the admission of air to the grate by the pressure of steam and the
temperature of the coil, by placing into the air inlet pipe a throttle valve and
attaching to the pipe coil a horse-shoe shaped branch pipe one end of which
communicates with the coils while the other end is closed and connected with the
axle of the throttle valve by a system of levers adapted to multiply any motion of
the closed end of the horse-shoe pipe and to transmit it to the throttle valve.
Another horse-shoe shaped pipe or equivalent device which is expanded or
deformed by an increase of pressure or temperature, and attached to the coil like
the regulating pipe already mentioned, is made to act on the inlet valve for the
feed water so as to control the water supply in accordance with the pressure or
temperature of steam existing in the coil.
Instead of a horse-shoe or U shaped pipe a movable piston or a flexible membrane
may be used in the manner already known, for acting on the air or water supply.

page_text: For regulating the escape of gases of combustion, and therefore the draught of
the fire, a liquid balance may be placed at the top of the system of pipes and
connected with a throttle valve inserted into the flue. Said liquid balance consists
of a circular pipe or annular vessel hinged on one side and connected with a pair
of concentrically curved hollow arms communicating at one end with the circular
pipe and carrying at the other end a balancing vessel. The apparatus being filled
with a liquid, the latter is made to boil when the temperature of the coil exceeds
a certain limit, thereby liquid is driven into the balancing vessel, so as to disturb
the equilibrium of the whole system and to cause the latter to turn on its hinge.
Dated this 10th day of September 1884

page_text: I, WILHELM SCHMIDT, of Brunswick, in the Empire of Germany, Engineer,
do hereby declare the nature of my invention for IMPROVEMENTS IN GENERATORS
OF STEAM, and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:—
The present improvement relates to the feeding of steam generators, which consist
of continuous systems of tubes and to which the water to be evaporated is supplied
in small quantities or portions. While heretofore the water has always been injected
from underneath into the said systems of tubes, which are frequently used for
feeding small motors, in the present case the water to be evaporated is introduced
from above into the upper part of the successively descending system of tubes
(which may form a serpentine or spiral, or several serpentines or spirals arranged
together or combined with each other) so that the water slowly running down flows
in a direction opposite to that of the heating gases or gases of combustion which
flow upward from below. The water, thus gradually heated, comes into contact
with hot and hotter fire gases, it is evaporated at last, and the steam escapes at the
hottest part of the tubular system. Thereby a correct counter-current is attained;
a cracking of the serpentine or coil at the lower part, where hitherto the water has
been injected, is prevented, the variations of temperature at the upper or inlet part
as well as at the lower or outlet part now being insignificant; also a better
utilization of the heat is effected.
In the drawing which illustrates the invention, Fig 1 is a vertical section, Fig 2
a sectional plan, Figs 3, 4 and 40 are detail views.
a is the continuous inclined system of pipes, in which the feed-water, introduced
above at a¹, flows down in a thin layer to be heated and evaporated.
The water being evaporated already in the centre of the coil so as to abstract but
a small quantity of heat from the pipes during its further progress through the
same, (the steam requiring but little heat for superheating), it is necessary to
protect the lower part of the pipe system from being heated to excess.
For this purpose I place between the fire-space and the pipe coil a ring z of fire
proof bricks with conical opening, while the lower part of the pipe coil is widened
so that this part is not placed in direct contact with the heating gases.
To the ring & may be added a short cylindrical shield 8¹ of metal situated inside
the space enclosed by the lowest parts of the coil.
This process of generating steam requires an automatic regulation of the pressure
and temperature of the steam, so as to prevent on the one hand a too high pressure
in the pipe coil and on the other hand an excessive temperature of the steam.
For this purpose I insert into the system of pipes two horse-shoe shaped branch
pipes c and d, Figs 3 and 4, one of which serves to cut off or diminish the supply
of water when the pressure of the steam is too high, while the other controls the
admission of air to the fire space and thereby the generation of heat when the
temperature is too high.
The horse shoe pipe c is so attached to the pipe coil that beat is given off from
the pipe coil to the horse shoe pipe, When the temperature of the pipe coil is too

page_text: high, the pressure is increased through the expansion of the fluid contained in the
pipe c, the U shaped arm stretches and actuates the lever m n, whereby the supply
of air is diminished by the closing of the valve k.
The second horse shoe shaped pipe d is equally inserted into the pipe coil, and
is directly influenced by the pressure existing in the pipe coil. If the pressure
increases, the U shaped pipe d stretches and diminishes the supply of water by
opening an air valve in the suction pipe of the feed pump.
Instead of a horse shoe or U shaped pipe, a movable piston or flexible membrane
may be used, in the manner already known, for acting on the air and water supply.
For regulating the escape of gases of combustion, and therefore the draught of
the fire, a liquid balance i may be placed at the top of the system of pipes, and con-
nected with a throttle valve inserted into the flue. Said liquid balance consists of
a circular pipe or annular vessel i i pivoting on the hinges x, and connected with a
pair of concentrically curved hollow arms g g communicating at one end with the
circular pipe and carrying at the other end a balancing vessel f. Counterweights w
balance the weights. The apparatus i i being filled with a liquid, the latter is made
to boil when the temperature of the coil exceeds a certain limit, thereby liquid is
driven into the balancing vessel f, so as to disturb the equilibrium of the annular
vessel ii and to cause the latter to turn on its hinge.
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 feeding steam-generators formed of or with a continuous
system of inclined tubes, which consists in introducing the feed water from the
top, for the purpose of converting it into steam during its down-flow.
་
2. A steam generator having a continuous system of inclined water tubes
provided with a water inlet at the top and a steam outlet at the bottom.
.
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