Improvements in or connected with the Artificial Supplying of Air to Steam Generator and other analogous Furnaces.
Year: 1895

page_text: PROVISIONAL SPECIFICATION.
Improvements in or connected with the Artificial Supplying of Air
to Steam Generator and other analogous Furnaces.
We, JAMES JONES MELDRUM, THOMAS FREDERICK MELDRUM, and JOHN
WESLEY MELDRUM, all of Atlantic Works, City Road, Manchester, in the
County of Lancaster, Engineers, do hereby declare the nature of this invention to
be as follows:-
This invention has reference to the combustion of the fuel, and means or con-
struction of apparatus or parts connected therewith, in furnaces of steam generators
and in other analogous furnaces; and the types of generators to which the invention
is capable of being applied with the greater advantage, are those wherein the gases
of combustion are conducted to or discharged at that end or part of the generator
at which the furnace front is disposed, as for instance, the marine type of return
tubular steam generator, or Scotch boiler, and analogous cases of steam generators
where the gases of combustion are discharged from the heating surface at the front
of the steam generator above, or in other position in relation to, the furnaces.
This invention, for convenience, will be described as applied to a steam generator
of the marine type that is, a generator having furnaces in the lower part of
the shell, and tubes above, through which the fire-gases are returned to the front
of the generator, where they are discharged into an uptake or smoke box, and
pass away. According to this invention, artificial draught is supplied to the
furnace by jet forcing apparatus, as steam jet apparatus, which delivers air into
the ashpit of the furnace, and maintains a pressure therein greater than that of
the atmosphere; while the air supplied to the jet apparatus is heated in a
continuous regenerator by the gases of combustion, alter they have left the
generator heating surface, by passing it over pipes or conduits through which the
gases pass and which are heated by thein, this air being caused to pass through
the regenerator by the rarefaction or exhaustion created by the jet apparatus at
their inlets, which are connected to the regenerator by a suitable conduit or
conduits. The air forcing apparátus consist of jet apparatus, such as blowers or
exhaueters of the "Meldrum" type, and their bodies lie practically wholly within
the ashpit under the bars, they being fastened or supported at their heads, and so
carried. About the inlets of the jet apparatus a chamber is formed, which is
connected by a conduit or passage with the space of the regenerator through which
the air passes, the said chamber being extended in front of the said inlets, and
provided opposite them with a detachable door (say of the "Meldrum" type), by
which access to said chamber and jet apparatus may be had when desired.
Further, in one arrangement, about this chamber another chamber above and below
is provided, into aud through which some of the air from the ashpit passes, and
from the upper chamber, through the inner perforated wall or plate of same, the
air passes into the furnace space above the fuel.
.In one special form of these chambers, the dead plate of the furnace front
constitutes a roof to the jet-apparatus air inlet chamber, and a floor to a passage
leading through from the firing door aperture to the space above the bars; while
the roof and sides' of this passage, form a division between such passage, and the
upper air chamber. The front plate of this furnace fitting will be practically even in

page_text: this case, and form the front end wall to all the chambers and parts described. The
inner wall of the air chamber round the firing door passage is, as stated, perforated,
and may be given such a disposition or angle as to cause the air which passes
through it, to issue as jets, directed more or less downwards onto the fuel on the
bars. The chamber below the blower inlet chamber, which communicates with the
upper air chamber, will be open on the inner side, and have in its front plate a
suitable door (as of the Meldrum type), by which access, when desired, may be had
to the ashpit direct, for withdrawing ashes, or for other purposes. And between
this lower chamber and the upper oue, a valve or damper, adapted to be operated
from outside, will be provided in the dead plate for making or cutting off com-
munication between these two chambers, and regulating the area or amount of
opening for the passage of air from the lower to the upper chamber, and to the
space above the fuel.
In one case, these chambers or furnace fittings described may project mainly in
front of the steam generator end, lying beneath the smoke box bottom, and the air
from the regenerator to the jet apparatus inlet chamber will pass by a conduit made
by separating the smoke box into two or more boxes, as the case may be, and
forming the space between them into said conduit, and connecting it with the said
inlet chamber.
In most cases, two or three blowers will be arranged and used in connection with
ench furnace, the chamber opposite their inlets being common.
As regards the regenerator, in one arrangement, in a marine type of steam
generator, the tubes through which the waste fire gases pass, extend between a
tube plate forming a roof to the smoke box or smoke boxes, and a tube plate above,
forming a roof to the regenerator chamber, and extending from side to side; while
through the part of side plates of the smoke box, forming the ends of the
regenerator chamber, an opening or openings for the inflow of air is or are
provided.
In some cases, the motor fluid for the jet apparatus, namely, steam (or air) is.
beated and dried previous to its being delivered to such apparatus. This is effected
hy conveying it to the nozzles of the jet apparatus by pipes, disposed in and
passing through the smoke box; and, in some cases, also through the passage for
conveying the hot air from the regenerator to the blowers.
The nozzles of the jet apparatus will be provided with a plug at their outer
ends, which will be accessible from the door in the front plate of the blower inlet
chamber, so that the interior of the nozzles, in situ, may be got at for cleaning, in
case of becoming choked, or other purpose.
Dated the 20th day of April 1895.
CHEESBROUGH & ROYSTON,
15 Water Street, Liverpool, Applicants' Patent Agents.
CUBIT LEIE DIECIFICAMON
Improvements in or connected with the Artificial Supplying of Air
to Steam Generator and other analogous Furnaces.
We, JAMES JONES MELDRUM, THOMAS FREDERICK MELDRUM, and JOHN
WESLEY MELDRUM, all of Atlantic Works, City Road, Manchester, in the
County of Lancaster, Engineers 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:-
t
*
1.
This invention has reference to the combustion of the fuel in furnaces of steam
generators and in other analogous furnaces, and means, or construction of apparatus
or parts connected therewith; and the types of generators to which the invention

page_text: is capable of being applied with the greater advantage, are those wherein the gases
of combustion are conducted to or discharged at that end or part of the generator
at which the furnace front is disposed, as for instance, the marine type of return
tubular steam generator, or Scotch boiler, and analogous cases of steam generators
where the gases of combustion are discharged from the heating surface at the front
of the steam generator above, or in other position in relation to, the furnaces.
This invention, for convenience, will be described as applied to a steam generator
of the marine type, that is, a generator having furnaces in the lower part of the
shell, and tubes above, through which the fire-gases are returned to the front of the
generator, where they are discharged into an uptake or smoke box, and pass away.
According to this invention, artificial draught is supplied to the furnace by jet
forcing apparatus, as steam jet apparatus, which delivers air into the ashpit of the
furnace, and maintains a pressure therein greater than that of the atmosphere;
while the air supplied to the jet apparatus is heated in a continuous regenerator
by the gases of combustion, after they have left the generator heating surface, by
passing it over pipes or conduits through which the gases pass and which are heated
by them, this air being caused to pass through the regenerator by the rarefaction
or exhaustion created by the jet apparatus at their inlets, which are connected to
the regenerator by a suitable conduit or conduits. The air forcing apparatus
consist of jet apparatus, such as blowers or exhausters of the "Meldruin"
type,
and their, bodies lie practically wholly within the ashpit under the bars, they being
fastened or supported at their heads, and so carried. About the inlets of the jet
apparatus a chamber is formed, which is connected by a conduit or passage with
the space of the regenerator through which the air passes, the said chamber being
extended in front of the said inlets, and provided opposite them with a detachable
door (say of the "Meldrum" type), by which access to said chamber and jet
apparatus may be had when desired. Further, in one arrangement; about this
chamber another chamber above and below is provided, into and through which
some of the air from the ashpit passes, and from the upper chamber, through the
inner perforated wall, or plate of same, the air passes into the furnace space above
the fuel.
In one special form of these chambers, the dead plate of the furnace front
constitutes a roof to the jet-apparatus air inlet chamber, and a floor to a passage
leading through from the firing door aperture to the space above the bars; while
the roof and sides of this passage, form a division between such passage and the
upper air chamber. The front plate of this furnace fitting will be practically even
in this case, and form the front end wall to all the chambers and parts described.
The inner wall of the air chamber round the firing door passage is, as stated,
perforated, and may be given such a disposition or angle as to cause the air which
passes through it, to issue as jets, directed more or less downwards on to the fuel on:
the bars. The chamber below the blower inlet chamber, which communicates with
the upper
air chamber, will be open on the inner side, and have in its front plate a
suitable door (as of the Meldrum type), by which access, when desired, may be
had to the ashpit direct, for withdrawing ashes, or for other purposes.
And
between this lower chamber and the upper one, a valve or damper, adapted to be
operated from outside, will be provided in the dead plate for making or cutting off
communication between these two chambers, and regulating the area or amount of
opening for the passage of air from the lower to the upper chamber, and to the
space above the fuel.
In one case, these chambers or furnace fittings described may project mainly in
front of the steam generator end, lying beneath the smoke box bottom; and the air
from the regenerator to the jet apparatus inlet chamber will pass by a conduit made
by separating the smoke box into two or more boxes, as the case may be, and
forming the space between them into said conduit, and connecting it with the said
inlet chamber.
In most cases, two or three blowers will be arranged and used in connection with
such furnace, the chamber opposite their inlets being common.

page_text: As regards the regenerator, in one arrangement, in a marine type of steam
generator, the tubes through which the waste fire gases pass, extend between a tube
plate forming a roof to the smoke box or smoke boxes, and a tube plate above,
forming a roof to the regenerator chamber, and extending from side to side; while
through the part of the side plates of the smoke box, forming the end of the
regenerator chamber, an opening or openings for the inflow of air is or are provided.
In some cases, the motor fluid for the jet apparatus, namely, steam (or air) is
beated and dried previous to its being delivered to such apparatus. This is effected
by conveying it to the nozzles of the jet apparatus by pipes, disposed in and passing
through the smoke box; and in some cases, also through the passage for conveying
the hot air from the regenerator to the blowers.
The nozzles of the jet apparatus will be provided with a plug at their outer
ends, which will be accessible from the door in the front plate of the blower inlet
chamber, so that the interior of the nozzles, in situ, may be got at for cleaning, in
case of becoming choked, or for other purpose.
In the accompanying drawings illustrating this invention,
Figure 1 is a front elevation partly in section, and Figure 2 a longitudinal
sectional elevation shewing improvements according to this invention applied to a
two-furnace steam generator of the "Scotch " or marine type; and Figures 3
and 4 are front part sectional elevation and longitudinal sectional elevation
respectively, of a three-furnace steam generator of the same type, provided with
our improvements.
Figures 5 and 6 are end elevations, partly in section, shewing modifications of
the invention.
In the different drawings and modifications the same letters and figures of
reference are used to denote the same or equivalent parts wherever they occur.
Referring in the first instance to Figures 1 and 2, a designates generally the
furnaces of the generator. b denotes the whole furnace front fitting. c are the
steam jet blowers of the "Meldrum" type. d'is the air heater or regenerator;
and e is a conduit forming communication between the regenerator d, and the
furnace front or fitting b. The bodies of the blowers c, as will be seen; lie practically
wholly within the ashpit, under the bars of the grate f, they being fastened at
their heads to the plate of the furnace front b and are so supported. The
mouths or entrances of these three blowers are open to the interior of a chamber i,
this chamber being formed about such entrances by the plates h, h1, h2, h3, and the
frout plate of the front fitting b, and communication between this chamber and the
conduit e is effected by the passage, which is formed in the furnace front fitting b
by the outer side plate thereof, the plate (which forms a stoking tunnel through
the fitting), and the diaphragm j', and the front and back plates of 6. The chamber i
has a separate door on the front plate by which access is had to it and the inlets
and nozzle cleaning plugs of the blowers e; the door shewn being provided with
wedge shaped lugs, fitting into corresponding catches on the front b, by which
an air tight joint is made between the face on the door and the front.
The stoking or firing tunnel is mainly formed through the fitting b, by the wall
or plate, and the plate (which constitutes the dead plate), forming the roof to
the chamber i; and in front of this tunnel the usual firing door k is provided.
Around the tunnel-excepting at the part where the passage is on one side of it-
a chamber is provided, and to this chamber, hot air from the ashpit a is introduced,
communication between the chamber and the ashpit being provided by the
passage m, which lies to one end of the chamber i. Between these passages / and m
is a regulating valve m worked from outside the front by the handle m² by which
the amount of air admitted to the chamber is controlled. The plate separating
the chamber from the furnace is perforated, as shewn, and through these apertures
jets of air are discharged, the jets being directed forward and at a slightly down-
ward inclination. These jets serve to mix up the gaseous products, of combustion
and to effect the combustion of those which are driven off from the fire in an
unburnt condition.
n

page_text: Access is had to the ashpit for clearing out ashes or other purposes, through the
passage o beneath the floor 2 of the chamber i, the front of this passage being:
normally closed by a door p, the face of which makes an air tight joint with the
face of the front fitting b by wedge shaped lugs and catches similar to those
specified in connection with the door directly above it.
The motor steam for the blowers cis supplied through the pipe and this steam
in the apparatus shewn is dried or superheated by disposing rows of this steam
supply pipe in the smoke box r above the fire-tubes of the steam generator. The
supply of steam is regulated by the cock q'; and it passes to the blowers from the
part of the pipe g within the chamber i, through hollow bridges of the blowers in
the usual way in the "Meldrum" blowers. The portion of the pipe 7 between
smoke box and the blowers is placed in the conduits e and ¹.
r
The regenerator d is, as will be seen, disposed in the uptakes of the generator,
and consists of vertical tubes t, through which the gases from the boiler tubes pass,
such tubes being supported top and bottom in an upper plate d', forming a roof to
the regenerator, and a lower plate d at the bottom, forming a floor to it, and a
roof to the smoke box r. The conduite between the regenerator d and the furnace
front fitting is formed by the side plates of the smoke boxes r, and a front
enclosing plate, and a bifurcated connecting casting e¹ connecting the bottom of
this part of the conduit, with the two passages of the two furnaces.
The
entrance for air to the regenerator is through an opening at d³, provided in the
side plate of the uptake.
The general action is as follows: When steam is turned on to the jet blowers c,
air from the chamber i is abstracted, and thereby outside atinospheric air is caused
to flow through the regenerator d where it becomes heated, down through the
passages e and , and into the chamber i, it having become heated in its passage
over the tubest of the regenerator. The air moved by the blowers is forced into
the ashpit, and the pressure therein is maintained by them above that of the
atmosphere. By this pressure some of the hot air (the quantity being regulated
by the extent of opening of the valve m³) passes from the ashpit by the passage m
into the chamber, and thence through the apertures in the plate 4, in jets, amongst
the flames and gases, whereby they are mixed and combustion of the unburnt parts
effected.
In the arrangement shewn in Figures 3 and 4, the construction of furnace front
fitting bis slightly modified; namely, the passage i to the blower inlet chamber i,
extends all round the tunnel plate ), and the chamber is disposed inside the
passage, air from the ashpit being admitted to such chamber through valves ni!-
shewn in dotted lines in the figure in the plate *. To the three furnaces a there
are two conduits e from the regenerator d, these being provided between the three
smoke boxes r; and the passages or conduits et at the bottom of these conduits_e,
lead both into the wing furnaces, and to the central one also. In other respects the
construction shewn in Figures 3 and 4 is similar to that set forth with reference to
and shewn in Figures 1 and 2.
In the modification shewn in Figure 5, the furnace front fitting b is shewn
applied to a steam generator separately from a regenerator, the air to the chamber i
in this case being conducted by the bifurcated conduit e¹ from below, from the
foot-plate say, and up round the sides of the walls forming the passage o between
the ashpit and the front of the furnace fitting. The air in this case may be heated
by a separate regenerator, or not, as the case may be, or conducted from any suitable
space connected with this neck e.
In the modification shewn in Figure 6, the conduit el is at the top of the furnace
front b, in lieu of below as in Figure 5; and in this case also, the air conveyed by
it may be brought from a separate regenerator, or not, or from any other space
from which it may be desired to draw air. These modifications, are substantially,
the furnace front fittings b set forth with reference to Figures 1 to 4, applied to a
steam generator or other furnace independently of the regenerator.

page_text: Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that, what I
claim is :-
1. In a steam generator or analogous furnace to the ashpit of which air is
supplied by steam jet blowers at a pressure greater than that of the atmosphere or
of that existing in the furnace above the fuel in the grate, the improved con-
struction and arrangement of blowers and hollow furnace front fitting described,
consisting of a separate blower air chamber (as i) having connected with it the
inlets of the blowers: substantially as set forth.
2. In a steam generator or analogous furnace to the ashpit of which air is
supplied by steam jet blowers at a pressure greater than that of the atmosphere or
existing above the fuel on the grate, the construction and combination of hollow
furnace front fitting and blowers, namely, the blowers c and air inlet chamber i,
with door ; air chamber with perforated plate outside or above the stoking
tunnel and communicating with the ashpit and ashpit aperture o with door p;
substantially as set forth with reference to and shewn in the drawings.
j.
3. In a steam generator to the ashpit of the furnaces or furnace of which air is
supplied by steam jet blowers at a pressure greater than that of the atmosphere or
of that existing above the fuel on the grate, the combination of steam jet blowers'
(as c), the bodies of which lie practically wholly within the ashpit under the grate;
a separate air blower air inlet chamber (as i) in the furnace front fitting, and a
continuous tubular regenerator, d; and conduits connecting said regenerator with
said blower air inlet chamber; substantially as herein set forth.
4. The arrangement, construction, and combination of parts or forced draught
and air regenerator apparatus in a steam generator of the kind specified and shewn,
comprising blowers e; hollow furnace front fittings b with blower air inlet chamber i,
and air chamber communicating with the ashpit; regenerator d; and passages
connecting the regenerator with the said blower air inlet chamber; all substantially
as set forth and shewn in the drawings.
5. The construction and arrangement of the apparatus for or connected with
supplying air to furnaces particularly set forth with reference to and shewn, in
Figures 1 and 2; Figures 3 and 4; and Figures 5, and Figure 6 of the drawings.
Dated this 21st day of February 1896.
CHEESBROUGH & ROYSTON,
15 Water Street, Liverpool, Applicants' Patent Agents.