Improvements in Steam Generators.
Year: 1886

page_text: Date of Application, 9th Nov., 1886.
Complete Left, 4th Aug., 1887.
Complete Accepted, 13th Sept., 1887.
RESERV
[Communicated from abroad by THOMAS MAIN, Engineer, of No. 45 Greenwich
Avenue, in the City of New York, United States of America.]
Improvements in Steam Generators.
HENRY EDWARD NEWTON, of the Office for Patents, 6, Bream's Buildings, Chancery
Lane, in the County of Middlesex, Civil Engineer, do hereby declare the nature of
this invention to be as follows:-
This invention relates to the class of steam boilers or steam generators having
furnaces which are closed, or from which the natural draught is usually excluded, and
which are supplied with a forced blast of air by means of a pressure blower or other
air-compressing device, whereby an uniform and predetermined pressure of air is
obtained for supporting combustion.
Ordinary coal, commonly employed for combustion, contains twenty five per cent
(25%) more or less of hydro-carbons and free hydrogen, and in order to burn these
elements, it is desirable that air should be shut off entirely from the ash pit, and
admitted only above the grate, while, when the fixed carbon of the coal is to be
consumed, it is most desirable that air should be admitted wholly below and through
the grate. It has been found that during nearly one third (+) more or loss of the
time between the intervals of charging a furnace, the air should be shut off from the
ash pit and admitted above the grate, in order to consume the hydro-carbons and free
hydrogen of the coal, and to prevent carbonic acid gas from ascending from the fuel
on the grate and mixing with the hydro-carbons; while during the remainder of the
time between the charges of fuel, air should be admitted below the grate in order to
burn the fixed carbon.
An important object of the invention is to supply to a closed furnace, the proper
amount of heated air both above and below the grate, at different periods between the
times of charging the furnace with fuel, in order to secure the most economical com-
bustion of fuel upon the grate.
In carrying out this invention, an air heater is employed, which is arranged in any
convenient smoke passage or connection of the boiler, and air may be supplied to this

page_text: heater by what is known as the Root Pressure Blower, or by any other well known
air compressing device. The closed boiler furnace above the grate is provided with a
hollow front, the inner wall of which is perforated, and in connection with the hollow
furnace front and the air heater, a system of air pipes is employed, whereby hot air
blast from the heater is delivered into the hollow furnace front, and also below the
grate; and in connection with such a system of hot air pipes, valves may be employed
whereby the hot air blast may be delivered, either to the hollow front above the grate,
or to the ash pit, or to both the hollow front and ash pit, as may be found to produce
the best and most economical combustion. The hollow furnace front does not serve in
itself as an air heater, nor does it cover any material portion of the front of the boiler
beyond the furnace proper, and therefore it does not form any material projection or
obstruction on the front of the boiler, and does not impede free access to the front of
the boiler for any purpose, such as caulking up leaky rivets or joints, or removing and
replacing a tube.
In one form of boiler to which the invention may be applied, and which is designed
for marine purposes, the furnace is arranged below the boiler, and the hollow front of
the furnace to which air is admitted, is arranged entirely within the line of the front
of the boiler proper. Where the invention is applied to a boiler having internal
furnaces, the hollow furnace front will be of a size or diameter to enter the furnace
flue, and will have its depth extending within the flue and inward of its outward end.
When applied to an ordinary multitubular boiler for stationary purposes, the hollow
furnace front will usually be arranged entirely inward of the cast iron front which
completes the boiler setting, and when the invention is applied to a locomotive, the
door may be constructed so as to form a hollow front, to which air under pressure is
admitted, or in other words, the hollow front may occupy only the space which is
occupied by the door, and may be co-extensive therewith.
The invention consists in the combination with a closed boiler furnace, having above
the grate a hollow front, the inner wall of which is perforated, of a system of air
pipes including an air heater arranged in a connection or smoke space of the boiler,
for delivering hot air blast to the hollow furnace front and below the grate.
The invention also consists in the combination with a closed boiler furnace, having
above the grate a hollow front, the inner wall of which is perforated, of a system
air pipes, including an air heater arranged in a connection or smoke space of the
boiler, for delivering hot air to the hollow furnace front and below the grate, and
valves for separately controlling the admission of hot air to the hollow front and below
the grate.
Tind this at. dead -----Lan 1000

page_text: COMPLETE SPECIFICATION.
Improvements in Steam Generators.
I HENRY EDWARD NEWTON of the Office for Patents, 6 Bream's Buildings,
Chancery Lane in the County of Middlesex, 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 :-
This invention relates to the class of steam boilers or steam generators having
furnaces which are closed, or from which the natural draught is excluded, and which
are supplied with air by means of a pressure blower or other air compressing device for
supplying air under a uniform and predetermined pressure. Ordinary coal, commonly
employed for combustion, contains twenty five per cent (25%) more or less of
hydro-carbons and free hydrogen, and in order to burn these elements, it is desirable
that air should be shut off from the ash pit and admitted above the grate, while when
the fixed carbon of the coal is to be consumed, it is most desirable that air should be
admitted through the grate. It has been found that during one third (+) more or less
of the time between the intervals of charging a furnaco, the air should be shut off
from the ash pit and admitted above the grate, in order to consume the hydro-carbons
and free hydrogen of the coal, so as to prevent carbonic acid gas from ascending from
the coal or coke on the grate, and mixing with the hydro-carbons, while during the
remainder of the time between the charges of fuel, air should be admitted below the
grate in order to burn the fixed carbon.
An important object of the invention is to supply to a closed furnace the proper
amount of heated air both above and below the grate, in order to secure the most
economical combustion of the fuel thereon.
The invention consists essentially in the combination with a closed boiler furnace
having above the grate a hollow front, the inner wall of which is perforated, of a
system of air pipes including an air heater arranged in a connection or smoke space
of the boiler, for delivering hot air blast to the hollow furnace front and below the
grate, and preferably also valves for separately controlling the admission of air to the
hollow front and to the ash pit below the grate.
In the accompanying drawings,
Fig. 1 is a vertical longitudinal section of a marine boiler having the furnace below
the boiler proper, and which embodies all the features of my invention.
Fig. 2 is a horizontal section on the irregular plane of the dotted line x x,
Fig. 3, which latter figure designates the boiler, one half in front elevation, and the
other half in vertical section, upon the plane of the dotted line y y, Fig. 1.
Fig. 4 is a transverse vertical section upon the plane of the dotted line z z,
Fig. 1, and
Fig. 5 is a side elevation of ordinary marine boilers with internal furnaces having
the invention applied thereto.
Fig. 6 is a front elevation of such boilers.
Fig. 7 is a horizontal section on the plane.of the dotted lines ss, Fig. 6

page_text: Fig. 8 is a front elevation, upon a much larger scale, or one of the
and appurtenances of Fig. 6.
Fig. 9 is a vertical section on the plane of the dotted line tt, Fig. 8.
Fig. 10 is a similar section on the plane of the dotted line u u, Fig. 8.
Fig. 11 is a horizontal section on the plane of the dotted line vv, Fig. 8.
Fig. 12 is a vertical longitudinal section of an ordinary multitubular stationary
boiler, illustrating how the invention may be applied thereto.
Fig. 13 is a vertical transverse section on the plane of the dotted line w w, Fig. 12.
Fig. 14 is a horizontal section through the setting, and a plan of the boiler shown
in Fig 12.
Figs. 15 and 16 are respectively a longitudinal section and front elevation of a
locomotive boiler to which the invention is applied; and
Fig. 17 is a transverse section on the plane on the dotted liner, Fig. 15.
Similar letters of reference designate corresponding parts in all the Figures.
Referring first to Figs. 1, 2, 3, and 4, A designates the boiler proper, which is or
may be of cylindrical form, and which contains heating tubes a a³, and is, as here shown,
surmounted by a dome A¹. The boiler and furnace are. arranged within a casing or
setting, which may be made of sheet or plate metal, B, lined with fire brick B'.
C designates the furnace, and D the ashpit, having grate bars c, and provided with
suitable fire and ash pit doors c¹². The setting has at the back a horizontal division
plate, deflector, or partition 6, which extends to the rear end of the boiler below the
uppermost tubes a¹. When the boiler is in operation, the products of combustion pass
under the bottom thereof to the rear, thence forwards through the heating tubes a to
the front connection d, thence rearwards through the tubes a¹ to the second or back
connection d, and finally make their exit at the chimney opening or outlet d², which
is provided with a suitable damper d³.
In order to catch sediment which may be deposited from the water in the boiler, a
sediment collector E may be employed, which is composed of longitudinal sections
hinged together at e, and which are of such width that when folded one on another,
they may be withdrawn through the manhole a² of the boiler. The introduction into,
and removal from the boiler, through the manhole, of a sediment collector which is
broad enough, when spread out, to cover the principal portion of the bottom of the
boiler, is thus provided for. I will here remark that I do not claim this sediment
collector as included in this invention. d designates the smoke door at the front
connection d.
For introducing air into the furnace, a system of pipes is employed with an air
heater, which may be arranged in any connection, or smoke passage or chamber of
the boiler, through which the products of combustion pass to the chimney outlet d².
In the drawings, a heater F is shown, composed of return and direct pipes or tubes
arranged within the back connection ', from which the products of combustion pass
to the chimney outlet . F' designates a pipe which extends, as here shown, from
the front of the boiler rearwards, and communicates with one end of the heater, and
from the opposite end or outlet of the heater F, a pipe F2 extends forward again to
the front of the boiler. The air to support combustion is supplied through the pipe F¹
by a pressure blower or other suitable air compressing device or apparatus, which is
adapted to deliver an approximately uniform volume of air at a given pressure, and
which is thereby distinguished from an ordinary fan blower. "What is known as
the Root Pressure Blower, or a piston air compressor, may be employed for this
purpose.
In most or all cases, it will be necessary to arrange the air heater above the level of
the grate, and hence a blower or air-compressing device will be necessary to produce the
circulation of air through the heater.
The pipe F, whereby the hot air blast is delivered from the heater F, communicates
with the furnace and ash pit above and below the grate c. The furnace above the
grate has a hollow front G, the inner wall p of which is finely perforated, and air
introduced under pressure into the hollow front G will be delivered in numerous fine
jets or streams. into the furnace above the fuel bed therein. The pipe F²,
which

page_text: extends forwards from the air heater F to the front of the furnace, communicates with
a valve box F, shown best in Figs. 2 and 3, and this valve box has a branch f, which
leads into the hollow front G, and is controlled by a valve, and a second branchƒ³,
which leads downward into the ash pit below the grate, as best shown in Fig. 3, and
is controlled by a valve ƒ³.
Immediately after introducing a fresh charge of fuel, the valve f³, controlling the
supply of air blast to the ash pit, is closed and the valve opened, so as to deliver
the air blast into the hollow front G, and thence through the perforations in the inner
wall p thereof, in numerous fine jets or streams, into the furnace above the fuel and
grate therein. The air thus introduced will serve to burn the hydro-carbons and free
hydrogen, and after these lighter combustible have been consumed, the valve f¹ may
be wholly or partly closed, and the valve s opened, so as to admit air below the grate
into the ash pit, for burning the fixed carbon of the fuel. By this means, just the
proper quantity of air is introduced at the proper points to insure the best combustion
and economical effects, and the supply to the furnace of enough air to act injuriously
in robbing it of its heat, is avoided.
The furnace door or front may have a register or sight hole k, as shown in Fig. 1,
for the admission of natural draught, or to see the effect of opening or shutting
the air valves at every point in the combustion of the charge of fuel.
Referring now to Figs. 5, 6, and 7, which represent marine boilers of the ordinary
type, having internal furnaces, H designates the breeching at the front of the boilers,
from which the products of combustion pass to the chimney ², in which is a
damper d. The chimney d comprises a section constituting an air heater F, and
which consists of tubes extending between two tube plates d. The products of
combustion pass through the tubes, while the air entering through the pipe F¹
passes around the tubes, and after being heated by contact therewith, passes
away through the pipe F
These
The construction of the hollow furnace fronts G for the boilers shown in Figs. 5
and 6, is best shown in Figs. 8 to 11 inclusive. The outer plate p' of the front comes
against the end of the furnace flue, and the depth of the hollow front to the rear
perforated wall P is inside the flue. The front G is provided with fire and ash pit
doors cc, which are above and below the grate c. The pipe is prolonged
downward in front of the furnace, and has branches ff, which communicate
respectively with the hollow front G and the ash pit below the grate c.
branches are controlled by valves fls. The valves are here shown as
rotary discs which may be controlled by handles . In the door c¹ is an air
damper k. The door c₁ also has a hollow perforated lining o, and heated air may
pass readily from the fixed portion of the hollow front into the space between the
outer plate and perforated lining of the door, and issue into the furnace through the
holes in the said lining.
In Figs. 12, 13, and 14, a common multitubular stationary boiler A, set in a casing
of brick work B, and having heating tubes a, is shown. C designates the furnace,
D the ash pit, and c the line of the grate. The furnace has a closed or hollow
front G, the inner wall of which is finely perforated. The products of combustion
from the furnace C pass rearwards under the boiler, thence forward through the
tubes a, and finally rearwards over and around the upper part of the boiler to the
chimney. In the smoke passage near the chimney is the pipe air heater F, to
which air may be supplied by a blower or other means, through a pipe F³, and from
the air heater a pipe F leads to the front of the boiler, and terminates in a valve
box F having branches leading to the furnace and ash pit above and below
the grate, and controlled by suitable valves as before described. Thus, provision
is made for introducing heated air in regulated quantity above and below the grate.
Figs. 15, 16, and 17 show a locomotive boiler A having heating tubes a, a furnace (,.
and ash pit D. The position of the grate is indicated by the dotted line c. From the
furnace C, the products of combustion pass through the tubes a to the smoke box
or chamber i, from which rises the smoke stack d², in which is a damper d³. In the
smoke box i is a pipe air heater F, to which the air is supplied by a blower or other
air compressing apparatus through a pipe F, and from which the heated air is supplied

page_text: through a pipe F2. Near the front of the boiler the pipe F2 communicates with the
valve box having branches ff controlled by valves or gates f¹ fs. The furnace
door is in a casing G, which is hollow, and has a perforated front wall
pipe
casing,
D. "By this
system of pipes, heated air may be supplied in properly regulated quantity above and
below the grate.
In order to secure the best results, it is necessary that provision should be afforded
for shutting off entirely the supply of air to the furnace, either above the grate or
below the grate, and also for introducing both above and below the grate at times.
In all the examples of the invention, pipes and valves are provided whereby heated
air may be shut off from the ash pit entirely immediately after a charge of fuel is
introduced into the furnace, and air supplied to the furnace above the grate only, and
whereby the supply of air to the furnace above the grate may be shut off
entirely, and heated air supplied to the ash pit only during the later period in the
combustion of the charge of fuel.
By reference particularly to Figs. 8 to 11 inclusive, it will be observed that the
outer imperforate plate p¹ of the furnace front comes close against the end of the
furnace flue or the tubular furnace, and the whole depth of the hollow front which
affords the air space is within the front end portion of the tubular furnace; hence it will
be seen that there is no cumbrous casing on the front of the generator, as has some-
times been used, and which prevenis ready access to the front of the generator for
caulking rivets, and doing such other repairs as may be necessary or desirable.
Having now particularly described and ascertained the nature of the said invention
and in what manner the same is to be performed, as communicated to me by my
foreign correspondent, I declare that what I claini is:—
1. The combination with a closed boiler furnace having above the grate a hollow
front, the inner wall of which is perforated, of a system of air pipes, including
un air heater arranged in a connection or smoke space of the boiler for delivering
hot air blast to the hollow furnace front and below the grate, substantially as herein
described.
2. The combination with a closed boiler furnace having above the grate a hollow
front, the inner wall of which is perforated, of a system of air pipes including an air
heater arranged in a connection or smoke space of the boiler, for delivering hot air to
the hollow furnace front und below the grate, and valves for separately controlling the
admission of hot air to the hollow front and below the grate, substantially as herein
described.
3. The combination with a tubular steam generator furnace, of a front plate closing
the front end of the furnace, and having combined with it an inner perforated lining,
in order to form an air space above the grate and within the furnace, and pipes and
valves which control the supply of heated air to the air space above the grate and
to the ash pit, the said pipes communicating with the front plate of the furnace,
substantially as herein set forth.