Year: 1888

page_text: I, CHARLES HENRY TWIST, of No. 22 Sutton Place, in the City and State of New
York, United States of America, Railway Builder, 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 my invention is to increase the efficiency of steam boilers by utilizing
the waste heat that now goes up the smoke stack; to prevent the unequal contraction
and expansion that now exists in steam boilers, thereby rendering the boilers less
liable to rupture or explode, and adding to the life and usefulness of the boiler; and
to prevent to a great extent the formation of injurious scale or sediment on the boiler
plates, flues or tubes.
The unequal contraction and expansion of a steam boiler is produced by several
causes, among which is the injection of cold feed water into a hot boiler. Another
cause, and probably the greatest, is the unequal distribution of the heat from the
furnace fire over, or along, the surface of the boiler, the boiler being hottest at the
end nearest the fire which is herein termed the front end and the coldest at the end
farthest from the fire which I term the rear or back end. Then again the plates at
the bottom of the boiler which come in direct contact with the fire are subjected to
greater heat than those at the top which are generally exposed to the air, or covered
with a non-conducting material.
Another source of damage or danger to a steam boiler is the depositing on the
plates and tubes of scales and mud, caused by the use of impure water, the foreign
matter being separated from the water by the action of the heat. In a plain cylinder
boiler the scale is deposited on the bottom and sides of the boiler, and, owing to the
construction of the boiler, it is easily cleaned, while in a tubular boiler the sediment
is deposited on the bottom of the boiler and around the flues and tubes. A heavy or
thick deposit of scale on the plates or flues of steam boilers is injurious to the boiler
inasmuch as the water cannot circulate beneath the scale and reach the metal, which
is thus left unprotected from the action of the fire and soon burns out, unless the
scale is removed. Some water is so pregnant with solid matter, such as alkalies,

page_text: gypsum, &c., that the water spaces between the tubes in the boiler, are frequently
entirely stopped up with scale, which can only be removed by taking the tubes out,
and this is a very expensive operation.
To secure a more perfect combustion of the fuel used in the making of steam, and
to utilize the waste gases that escape up the chimney, has been the study of the users
of steam for many years. Many devices have been resorted to with varying success,
but with the best appliances and under the most favorable circumstances not over
60 or 75 per cent. of the fuel is actually utilized, the balance escaping in the form of
gases at a temperature of from 300 to 800 degrees Fahrenheit (according to the kind
of boiler and draft used), and causing a loss to the consumer of 25 to 40 per cent. of
the actual heat produced, besides the extra labor that is necessary to handle the fuel.
With the steam boilers in common use, under ordinary circumstances the waste
amounts to fully 50 per cent. The objects of my invention I accomplish by utilizing
a portion of the waste heat to heat the feed water before it enters the boiler; also by
utilizing the waste heat, when not used in heating feed water, to increase the capacity
and efficiency of the boiler, by creating a perfect circulation through the entire
length of the boiler, thereby keeping the water at a more uniform temperature, and
making the boiler less liable to uneven contraction and expansion; and also by
heating the feed water before it enters the boiler, to cause the solid matter in the
water to be deposited at or near the place where the water enters the boiler, where
it can be collected in an ordinary mud drum, and blown out of the boiler at the
pleasure of the engineer.
In the drawings figure 1, is a longitudinal vertical section of a stationary boiler A ;
taken on the line of figure 3, showing one arrangement of the pipes and con-
nections which I employ in conjunction with a boiler of this style, and this figure
shows, also, the fire box B, the smoke box C, from whence the products of combustion
coming from the fire pass up through and out of the smoke pipe, the upper part of
which is not shown..
Figure 2, is a front view of the boiler cylinder and the connections at the end
nearest the fire, while figure 3, is a view of the rear end of the boiler cylinder and
showing the pipe and coil connections at that end which are located within the smoke
box. And figure 4, is an enlarged side view partly in section of the steam con-
nection d, combined with the water pipe a which parts are also shown in figures 1
and 2.
In these drawings, A represents the boiler, B the fire box, and C the smoke box ;
a, is an open pipe shown as being made of several pieces, but which need not be
so made, extending from a point near the bottom of the boiler up to a point a short
distance below the water line and through the water to the rear end of the boiler,
and into the smoke-box, where it opens into a coil & located in the smoke-box C, or
where it will receive heat from the fire, the coil 6 being made to empty into the lower
part of the boiler, by means of a short pipe or extension c. At the front end of the
boiler is a steam pipe d, which has an open end within the boiler above the water
line, in order that it may take the live steam, and this pipe communicates with the
water pipe a, and may have a small end or steam jet d', so that more force will be
imparted to the steam when it enters the pipe a. A similar steam pipe e passes out
of the rear end of the boiler, and enters the return pipe c, but may enter the coil b
instead of this return pipe, and this steam pipe may also be provided with a jet at
that point if desired. The connection is to permit the feed water to enter the coil b,
in order that the feed water may be heated in its passage to the boiler, both by
mingling with the hot waters in the coil b and also by reason of the heat imparted to
such coil b. The course of circulation is indicated by the arrows.
The heating coil bis placed in the smoke-box or where it will be surrounded by
the heat, and having a direct communication with the boiler becomes as it were a
part of the boiler, and on filling the boiler with cold water, the coil and the pipe a
are also filled provided that they do not extend above the water line of the boiler.
The pipe a can be run through the boiler as shown, and I prefer to have it so,
but this arrangement of the pipe is not essential as it may be made to extend along

page_text: on the outside of the boiler, or it can be arranged wholly within the boiler. But
whether as shown or otherwise located, it may be placed at any desired height not
above the water line unless jets are used in connection with it as hereinafter
described. So also the form of the water containing receptacle or conduit shown as
the coil within the smoke-box may be varied.
The action produced by the connection of these parts with a steam boiler will be as
follows:
And
After the boiler is filled with water to the desired height in the ordinary manner
the fire is then started under it and the process of making steam commences.
when the water in the boiler becomes heated, currents aro established or formed by
the water flowing upward and away from the source of the greatest heat while the
colder water flows toward the most heated part to replace the other, and in its turn
becomes heated and thus the action of the water, produced by the heat, is continued.
The direction of the currents will be upward and from the fire, on the surface, and
downward and towards the fire in the lower part of the boiler. The water at the
front end of the boiler will of course, boil sooner and be hotter than the water which
is farthest from the fire. As the water becomes heated the hot water in the front end
rises and a portion of it will flow up through the pipe a and force the cold water that
is in the pipe through the coil b which will thus be made to empty its water into the
boiler through the short connection c. In this manner the circulation is started
throughout the entire length of the boiler and the cold water at the back end is
forced forward to replace the hot water at the front end and to make room for the hot
water that is being forced through the coil, and into the back end through the short
connection c. The circulation thus begun is continued so long as the water is kept
heated. The water is thus kept at an even temperature or nearly so at all points in
the boiler and consequently the contraction and expansion of the plates and tubes is
accordingly rendered even or uniform.
In order to give increased velocity to the circulation when required I make use of
one or more steam pipes or jets d and e which are inserted into the water circulating
pipes at such points as may be found desirable. In the drawings I show two such
steam jets entering the water pipes at the front and rear ends of the boiler, but
different boilers may require the steam pipes or jets at other points while some
boilers need only the circulation that is made by the use of the water pipes. I prefer
the steam jets made as shown in figure 4 of the drawings which is a section of a jet
made on the same principle as an injector, but this form is not essential although
desirable.
By using the steam jets in connection with the water pipes a I make it much
easier to feed the boiler, as the cold feed water condenses the steam from the jets and
increases the circulation by which it is carried along into the boiler, being heated as
it passes through the coil."
By using steam jets to increase the velocity of the circulation, the pipe a may be
raised above the water line, as the steam from the jets will raise the water to that
height with the assistance of the hot water pressure from the boiler, a small jet of
steam only being necessary.
The pipe a may be inside of the boiler it convenient, in which case the extension of
the same beyond the front end may be dispensed with altogether, provided a proper
connection is made with the coil b, at the back end of the boiler, and if desired two
or more similar pipes and coils may be used.
I have shown one feed water connection but two or more may be made if required
or desired.
The connection permits the feed water to enter the coil b, near the top thereof,
and this assists the heating of the feed water before it enters the boiler.
I do not confine myself to the use of the appliance in the form shown in the
drawings, for the same may be varied in many respects, and different makes and kinds
of boilers will require variations from the form of the appliances shown in the drawings,
but I do confine myself to the same general arrangement in order that may
accomplish the object of my invention which I have described.

page_text: 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. A means for increasing the circulation of water in a steam boiler, consisting of
a pipe located within said boiler and extending from end to end thereof, in combina-
tion with one or more steam pipes or jets having communication therewith, said first
mentioned pipe being adapted to receive water and steam from said boiler, at or near
one end thereof, and to discharge the same at or near the opposite end substantially
as and for the purpose set forth.
2. A means for increasing the circulation of water in a steam boiler, consisting of
one or more circulation pipes combined therewith and adapted to receive water
therefrom at or near the front or fire-box end thereof, said pipe or pipes extending to
the rear or colder end of the boiler and communicating with a conduit opening into
such rear end, in combination with one or more steam pipes or jets having communi-
cation with the said circulation pipe or pipes with said conduit; whereby the water
and steam entering the said circulation pipe or pipes are discharged into the rear or
colder end of the boiler and the circulation increased, substantially as and for the
purpose set forth.
3. A means for increasing the circulation of water in a steam boiler consisting of
one or more coils or conduits disposed to be heated by the fire and a feed water pipe
communicating with said coil, in combination with one or more pipes adapted to
bring water from the boiler, one or more steam pipes or jets made to enter said water
pipe or said conduit, and a return pipe for discharging the water from said conduit
into the boiler the whole being arranged substantially as and for the purpose set
forth.
4. A means for increasing the circulation of water in a steam boiler, consisting of
a pipe a, coil b and a return pipe c the same being arranged in the manner shown
and described for the purpose set forth.
5. A means for increasing the circulation of water in a steam boiler, consisting of
the pipe a, coil b, and return pipe c, arranged as described, in combination with the
steam pipes d and e substantially as and for the purpose set forth.
Dated this 22nd day of May 1888.
CHARLES H. TWIST.