Improvements in Steam Boilers.
Year: 1897

page_text: Date of Application, 18th Jan., 1897-Accepted, 2nd Oct.,
1897
COMPLETE SPECIFICATION.
Improvements in Steam Boilers.
I, HORACE SEE of 1 Broadway in the City and State of New York, United States
of America, 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 invention relates to steam boilers more particularly designed for marine use.
The invention consists in the construction of the boiler whereby it is enclosed
in an air casing into which air is forced. In the arrangement of the apparatus
shown in Figs. 1 and 2 the air enters the upper part of the casing and passes down-
ward becoming heated by contact with the boiler. It then enters front and side
openings in the ashpit and thence passes up through the grate and fire space to the
uptake. In this way the heat radiated from the boiler is taken up by the air,
high temperature between the decks of the vessel and escape of steam from leaks
in the boiler is prevented. The construction is also such as to obviate danger of
back draft when the fuel supply doors are opened.
In the arrangement shown in Figs. 4 and 5 the air enters the air casing at the
bottom and is exhausted at the top, thus as before becoming heated by passage in
contact with the boiler, and also taking up any dust, smoke or escaping steam.
It is then forced directly into the ashpit and thence passes up through grate and
fire space to the smoke stack.
Referring first to Figs. 1, 2 and 3. Fig. 1 is a vertical longitudinal section;
Fig. 2 a vertical transverse section and Fig. 3 is a plan view. A represents the
fire space, B the grate, C the ashpit and D the steam drum. At E are water tubes
connected to drum D by inclined water tubes F. G and H are the front and back
walls of the fire space. The metal casing I covers the sides of the fire space and the
exterior of the front and back walls and extends above the steam drum D where it
connects with uptake flue J. K is an exterior casing forming a chamber so
enclosing the boiler that a free air space is formed around the boiler except in
front of the front wall G and in front of the steam drum D.
Any suitable air forcing apparatus communicates with casing K by conduit L.
The air blast entering at L passes downward between casings K and I and so
becomes heated. It enters the ashpit through the side openings N and also passes
through space 0 to the ashpit through front openings M. Thence it proceeds
through the fire grate between tubes F and drum D to uptake J.
From the time that the air enters the inlet conduit L until it escapes at the
uptake J it has an unobstructed flow through large passages and is not impeded
by valves or regulators. The entire boiler-the front portion excepted-is then
surrounded with an envelope of cool air which takes up the radiated heat-and thus
prevents the same being communicated to the atmosphere. This is advantageous
when the boiler is used for marine purposes. The large heating surface exposed
to the incoming air blast also ensures the elevation of the latter to a high
temperature before it passes to the grate. So also the enclosing of the boiler in an
outer casing or bulkhead prevents any escape of steam due to leakage.
In the front of the outer casing K are hinged doors as P, and in the inner casing
9

page_text: and communicating with the fire space are hinged doors as Q. These doors are
connected by a chain R so that the opening of the outer door P also causes the
opening of the inner door Q. On the outer door P there is also a cam S which
when said door is closed bears against the inner door and effects the shutting of
said door at the same time. There are also doors as T in the outer casing in front
of the openings M through which access can be had to said openings. By this
construction the fireman may manage the fire from outside the outer casing K
which may be the bulkhead of a vessel. It is important to notice also that back
draft when the inner door Q is opened is entirely prevented; because the incoming
blast not only passes unobstructedly below the grate through the ashpit but also
directly into the space above the grate when said inner door is opened; this current
above the grate effectively preventing the current delivered below the grate finding
an exit at the opening.
In order to enable the boiler to employ natural instead of forced draft as herein-
before described, I provide a ventilator or ventilators, as U in the upper part of
the casing K, and arrange regulating valves V therein.
The air then passes
downwards from these inlets to the ashpit, and through the grate and intervals
between the tubes to the uptake as before.
Fig. 4 is a vertical longitudinal section and Fig. 5 is a front view and partial
transverse section of the second arrangement of my invention.
Fresh air is drawn in at the opening H' in the air casing L' and passes around
the exterior of the boiler shell $i proceeding below the deflecting plate K¹ to the
compartment L' in the rear of the boiler. Thence it passes forward beneath the
deflecting plates M₁ until it reaches the openings N1 between the forward ends
of said plates and the vertical wall O¹. The current then returns to the compart-
ment P₁ in rear of the boiler and thence proceeds forward through the tubes Q
to the compartment R¹ which extends across the boiler front and communicates
with the conduit B' leading to the air forcing apparatus A².
The tubes Q are disposed above the boiler shell.
The blast having become heated by contact with the boiler shell and by passing
through the tubes, is delivered by the blower A¹ to the ashpit F by the pipes D¹
and E and thence passes through the fuel on grate G¹ to the uptake a¹, thence it
proceeds through the tubes 61 which are in the lower part of the water space of the
boiler to the front chamber or connection c¹. From said chamber the mingled air
and products of combustion pass around the tubes Q and rearward to the stack J¹.
In this way the escaping draft passing over the tubes Q gives up its heat to the air
which passing through said tubes is proceeding to the blower.
The construction herein before described is especially adapted to marine use, as
indicated in the drawings. The boiler is in fact disposed in an air tight room,
the walls of which form the air casing I¹ through which the blast is drawn by the
blower and in which it becomes heated before being forced into the furnace. The
boiler is thus continually surrounded with the cool incoming air which receives
and absorbs the heat which otherwise would be radiated into the between deck
space. Furthermore, inasmuch as the air is drawn through the air casing before
it is forced into the ashpit, any leaking gas or steam cannot escape between decks
but enters into the current which is drawn into the ashpit.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what
I claim is:
1. A steam boiler having an air casing surrounding the top, sides and rear and
extending in front of the fuel supply and draft openings, an air forcing apparatus
communicating with the upper part of said casing and openings in the front and
sides of the ashpit whereby the air blast is caused to descend through the air casing
to said ashpit openings thus becoming heated by contact with the boiler and then
to rise through the grate and fire space to the uptake, substantially as described.
2. The combination with a steam boiler of a bulkhead or partition in front of

page_text: the fuel supply and ashpit openings an air blower communicating with the space
between bulkhead and boiler, a hinged door closing the fuel supply opening and
a hinged door corresponding thereto in said bulkhead and a mechanical connection
between said hinged doors whereby the operation of the outer door causes the
simultaneous operation of the inner door, substantially as described.
5. A steam boiler having an air casing enclosing the side and rear walls, and
an air forcing device having the suction end communicating with the air chamber
formed by said casing and its delivery end with the ashpit; whereby heated air
is drawn from said chamber and forced into said ashpit, substantially as described.
4. In combination with a steam boiler an air casing enclosing its side and rear
walls and provided with deflecting plates and an air forcing device being connected
with the top of the air casing to exhaust air therefrom and with the ashpit to
deliver the heated air thereto, substantially as described.
Dated this 5th day of January 1897
Haseltine, Lake & Co.,
HORACE SEE.
45 Southampton Buildings, London, W.C., Agents for the Applicant.