Improvements in Apparatus for Heating, Drying, and similar Purposes.
Year: 1889

page_text: Date of Application, 8th July, 1889-Accepted, 7th Sept., 1889
COMPLETE SPECIFICATION.
Improvements in Apparatus for Heating, Drying, and similar
Purposes.
JAMES JOHNSTON Civil Engineer, of 10 Balloon Street Manchester 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 improvements relate to the construction of that kind of apparatus for heating,
drying and other purposes by means of wrot iron or steel tubes partially filled with
water or other suitable material and sealed at each end, and for which Letters Patent
number 636 were obtained by Loftus Perkins on the 7th of March 1865, and to
which subsequent improvements have been made and Letters patent obtained by
myself.
In the following description of my invention in order that the same may be better
understood reference is given to the accompanying drawings which are drawn to a
scale of inch to a foot and are as follows:-
Sheet 1. Fig. 1. A longitudinal section through a Baker's steam heated oven,
shewing the position of the sealed steam tubes.
Fig. 2. A plan of the above Oven.
Fig. 3. A cross section through the fire chamber.
4. A cross section through the middle of the oven.
Sheet 2. Fig. 1. A longitudinal section of a Baker's steam heated oven with
travelling baking-plate of improved construction.
Fig. 2. A plan of above shewing course of flues.
Fig. 3. An elevation of the front of oven shewing the sliding door and
travelling arrangement.
Fig. 4. A cross section through the fire chamber shewing the arrange-
ment of flues.
Fig. 5. A cross section through the middle of oven.
Fig. 6. A section of the novel heating and cooling damper shewing the
damper slide drawn for rapid heating of oven.
Fig. 7. Ditto shewing the air slide drawn for rapid cooling of oven.
My improvements consist firstly of an arrangement of flues conveying the heated
gases from the fire, under and over the body of the oven, after acting upon the tubes
in the fire-chamber (A) in order to utilize the heat that would otherwise be wasted.
By this means the temperature of the oven can be raised and maintained with a
smaller fire and thus effect a saving in fuel.
The arrangment is as follows:-
By reference to Fig. 3. Sheet 1. it will be seen that by means of dampers situated
at C, the heated gases from the fire can be conducted either directly into the main
flue (D) by the passages (E) or when a higher temperature is required in the oven,
they can be diverted downwards into the passages (F) running under the oven then
upwards through the passages G and along the top through the passages H into the
main flue D.
Another arrangement of these flues is shewn on sheet 2 which though applicable to
any form of steam heated oven is specially adapted for an oven with travelling baking
plate as represented. In this arrangement. the heated gases from the fireplace A. can
be allowed to pass directly into the main flue B by opening a damper C but if it is
desired to increase the bottom heat, the damper C is closed, the heated gases then
following the direction indicated by the arrows, pass down the passages D and thence
under the oven bottom at E returning down the centre passage Finto the upright
Blue G and then into the main flue B.

page_text: My improvements further consist in the introduction of rapid heating or cooling
dampers S. Figs. 1 & 4 Sheet 2. and shewn on a larger scale in Figs. 6 & 7 sheet 2-
these dampers are constructed as follows:-
The body T is formed as a box with open ends and having part of the top open and
covered with the damper slide (U) and one end closed with the air slide (V). This
damper is fixed as shewn in Fig. 1. in connection with a passagei W leading into the
interior of the oven. When it is desirable that the oven should be heated rapidly
or that the temperature should be raised to an exceptional degree, the damper slide. Ū
is drawn as shewn in Fig. 6 and the heated gases from the fire allowed to pass as
indicated by the arrows through the passage (W) into the inside of the oven, or again
when it is desirable to quickly cool the oven the damper (U) is closed and the air
slide (V) is drawn out as shown in Fig. 7. giving a clear passage from the outside
into the oven and thus allowing the air to rush into the interior and cool the same.
Another feature of my improvements consists in the introduction of specially long
tubes of wrot iron or steel (B) Figs. 1 & 2 Sheet 1. ranged on each side of the fire-
space (A) and projecting into the chambers A' as shewn in Fig. 2. Sheet 1. they then run
under the bottom of oven and are bent so as to run up the front and along the top as
shewn on Fig. 1 Sheet 1. When these tubes are fixed in an oven the requisite
amount of heat can be maintained with a fire of considerably reduced proportions thus
effecting a saving in fuel.
My improved arrangement of travelling baking plate for a steam oven is shewn on
Sheet 2. At the mouth of the oven I place a casting H Figs. 1 & 3 which is firmly
secured to the baking plate by being bolted to the Tirons (J) Fig. 1. affixed to the
underside of plate so as to be perfectly rigid. To this casting H are bolted two
cast iron legs or supports (K. K.) which carry at the bottom an axle (L) on which
are fixed two flanged wheels or runners (M) which last run in tramway rails (N) let
into and level with the floor of the Bake house. The other end of the baking plate
travels on a pair of runners (P) which roll along two T iron bars (R) fixed in
the oven.
It will be seen that this travelling arrangement dispenses with the construction
of standing rails formerly necessary and which took up so much space, in the Bake
house.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is: :-
1. An arrangement of flues in a steam heated oven to convey the heated gases from
the fire through the body of the oven after the said, gases, have acted upon the heating
tubes in order to maintain the temperature of the oven with a less consumption of fuel
than heretofore, as set forth and described in the foregoing.
2. The introduction of dampers of peculiar form, constructed to, allow the heated
gases from the fire to pass directly into the interior of the oven in order to rapidly
heat the same, or otherwise to allow a draught of cold air to pass inside in order to
rapidly cool the interior, as may be required, as set forth and described, in the
foregoing.
Dated this Fifth day of July 1889.