Year: 1886

page_text: .18 18 .
I, ANDREW LAING of N° 2 Glenavon Terrace, Crow Road Partick near Glasgow
Lanarkshire 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 :-
.
My invention relates to apparatus for ventilating stoke holes by withdrawing
the heated and foul air therefrom and supplying boiler fires with air so withdrawn
under pressure and farther heated. As such provisions are more particularly
required in steam vessels, I will describe, several modified forms of apparatus
according to my invention suited to several types and arrangements of marine
boilers, referring to the accompanying drawings, in which as far as possible, similar
reference numbers are employed to indicate corresponding, parts.
Fig. 1 is a front sectional elevation shewing apparatus according to my invention
applied to two cylindrical boilers which may be duplicated in length as shewn in
longitudinal section by Fig. 2 or may be single in length, as, shewn in Fig. 3. By
means of a fan or pair of fans 1, or other known exhausting and blowing apparatus,
the air is drawn from the stoke hole along passages. 2 formed between the uptake 3,
and air casing 4, then through an annular space 5 between the funnel 6 and air
casing 7 where the air is somewhat heated. It is then driven by the fan through
channels 8 and passages 9, that may, be plain or corrugated or may be tubes
formed or arranged within the uptake, so that the air is farther heated by the
products of combustion on their way to the chimney. The heated air from 9
passes through a channel 10 into a chamber 11 formed under the smoke box, and
between the face of the boilers and the furnace front 12. From the chamber 11
the air is passed through openings 13 to the ashpits 15 through doors 14, which
can be adjusted to give each furnace the required supply. It is convenient to work
the doors 14 by levers which form or actuate catches for the ash pit doors 16 so
that these doors cannot be opened till the air doors 14 are closed, the escape of
heated air to the stoke hole being thus prevented.
Above the firing doors 17 are valves 18 by which air can be admitted from the
chamber 11 to the spaces 19 between the inner fronts 20 and the air plates 21, and

page_text: also to the spaces 22 between the doors 17 and the air plates 23, so that it can pass
to the furnaces through the perforations in the plates 21 and 23. By leaving
the valves 18 open while firing, the influx of colder air from the stoke hole to the
furnace is prevented.
The uptake may be divided by partitions 24 into separate ascending channels,
one for each furnace, and each of those channels may be governed by a sliding
valve or damper 25 worked by a lever 26 and rod 27, so that the draught of each
furnace can be separately regulated. Instead of sliding valves, throttle valves 25
may be used as shewn in Figs. 5, 9, 11, 13, 15 and 17.
In the arrangement shewn by Figs. 4, 5 and 6, the fan'1 draws the air by the
passages 2 from the stoke hole and from the space surrounding the chimney casing,
and drives it through the casing 5 either directly by the passage 8, as shewn on
the left side of Fig. 4, or through the heating channels 9 in the uptake, as shewn
on the right side of Fig. 4, to the chamber 11, whence it passes to the furnaces as
already described.
Figs. 7, 8 and 9 shew an arrangement of the channel in cases where several
boilers are grouped together.
Figs. 10 and 11 shew an arrangement applicable to the low type of marine boiler.
In this case the air is drawn from the stoke hole &c by the fan 1 which drives it
through a helical channel 28 surrounding the funnel 6 and through space 8 between
the uptake and the air casing 4 along channels 9 under the front and a central
passage 29 to the chamber 11 whence it passes to the furnaces in regulated
quantity as before described.
Figs. 12 and 13 shew an arrangement similar to that shewn by Figs. 10 and 11
modified to suit boilers of locomotive kind or such as are used in torpedo boats.
The air is drawn from the stoke hole through the space 2 between the uptake and
the air casing 4 through the helical passage 28 to the fan 1 which drives it through
passages 8, 9, 30 and 29 to the ashpit 31. By a passage 32 led up from 31 air
can be admitted by the furnace door. As in this arrangement the air supply to
the furnaces is not taken from a low level in the stoke hole but passes along closed
channels, steam can be kept up even when the stoke hole is flooded, and should a
tube give way, the occupants of the stoke hole are protected.
In the arrangement shewn by Figs. 14, 15, 16 and 17, the air is drawn by the
fan 1 from the stoke hole through the space 2 and the funnel casing 5 and driven
through the passage 8 to the chamber 11 and thence to the furnace.
Figures 18, and 19 shew to an enlarged scale details of the doors and their
fastenings.
On the fire door 17 is the ordinary latch 33 and keeper 34. On a pivot is
mounted a lever 35 shewn separately at Fig. 22 one end of which is made with a
lug 38 that can press the door 17 close home. Jointed to the end of lever 35 is
a link 39 made with a slot in which a pin on an arm 40 can slide. This arm is on
a spindle to which are attached the doors 14. The link 39 is jointed to the bolt 42
of the ashpit door shewn separately at Fig. 23 and its slot is so arranged that
the doors 14 must be shut before the bolt 42 is lifted to admit of the ashpit
door 16 being opened, the escape of heated air to the stoke hole being thus
prevented.
Figs. 20 and 21 shew modifications of the door connections. In this case there
are two furnace doors 43 and 44 connected by a link 45, so that both doors open
and close together. The bolt 42 for the ashpit door is as before hinged to the
slotted link 39, and a pin on an arm 40 moved by the lever 35 works in the slot of
a rod 41 which is linked to the doors 14. Thus on depressing the lever 35 the
doors 14 are closed before the ashpit bolt 42 is withdrawn.
I am aware that arrangements have been proposed for supplying boiler furnaces
with air driven by a fan along heated surfaces presented by the chimney boilers
and their casings. I therefore make no general claim to the use of a fan for forcing

page_text: the draught nor to the arrangement of channels in such a manner that the air
drawn or forced along them by the fan is more or less heated on its way to the
furnaces, but,
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
claim is :-
1. In apparatus for ventilating stoke holes and heating air supply to boiler
furnaces, the combination of a fan or other ventilating machine with suction
channels opening from the stoke holes and formed as casings to the smoke boxes
and uptakes with or without heating channels formed in the chimney casing and in
the uptake and with an air space surrounding the furnace fronts and communi-
cating with the furnaces by openings governed by adjustable valves, substantially
as herein described and illustrated by the accompanying drawings.
2. In apparatus such as is referred to in the preceding claim, so connecting the
ash pit doors to the valves which govern the air supply to the ashpits, that when
the ash pit doors are opened, these valves are closed, substantially as and for the
purpose herein set forth.