provements in Apparatus for Heating, Drying, and other Purposes.
Year: 1885

page_text: COMPLEIE DIECIFICATION
Improvements in Apparatus for Heating, Drying, and other
Purposes.
JAMES JOHNSTON of 10 Balloon Street Manchester in the County of Lancaster
Civil and Mechanical Engineer do hereby declare the nature of my invention for
IMPROVEMENTS. IN APPARATUS FOR HEATING, DRYING AND OTHER PURPOSES 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 wrought iron 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.
In the following discription of my invention in order that the same may be
better understood, reference is given to the accompanying drawings of a steam
oven heated with Perkin's patent tubes, and shewing my improved mode of
construction, drawn to a scale of half an inch to a foot and are as follows:-
Fig. 1. is a longitudinal section of a steam oven.
Fig. 2. is an Elevation of the firing end of the oven.
Fig. 3. is a plan of the oven shewing the internal arrangements.
Fig. 4. is a cross section of the oven.
'
Part of my improvement consists in building in at a convenient height a
casting (A) shewn in section in Fig. 1, and which for convenience I cast in two or
more pieces and bolt them together as shewn on Fig. 2. In this casting I form a
number of holes (B) at any requisite distances from each other to receive the ends
of the bottom row of heating tubes (C) which tubes also serve the purpose of fire-
bars within the fire space (D) In this same casting I also form recesses (E) to
receive the fireclay blocks (F) which form the divisions between the firing door-
ways (P) and are shaped so that one part of them shall fit down into the recesses (E)
and part sit on the top plate (R) of the casting (A). It will be seen that by means
of the splayed form of these blocks on plan and the sloped portion (G) of the
casting (A) that access is given through the firing doorways to every part of the
fireplace at once from the outside.
Upon these last mentioned blocks I place fireclay slabs (H) which are notched
to receive the ends of the top row of heating tubes (J) these tubes by reason of

page_text: their being fixed over the fire, have formerly received a greater amount of heat
than the bottom row of tubes (C) I therefore make the blocks (F) with their
sides inclined inward so that the width of the fire space at the level of the top row
of tubes is less than at the bottom, thus diminishing the amount of heating surface
of the top row of tubes, and giving a more equal temperature to the two rows of
heating tubes than has formerly existed.
In the casting (A) are formed the openings (K Fig. 1) covered with flap doors (L)
for withdrawing the ashes and for regulating the draught to the fire, these ash
doorways extend the whole length of the fire place so that access is given to every
part of the ash place.
On account of the proximity of the fire to one end of the oven it has generally
been found that that end attains a higher temperature than the other end of the
oven. In order to remedy this defect I insert a layer (M) of any material which
will arrest the transmission of heat, preferably of asbestos, which I bolt to the
back plate (N) thus attaining a greater uniformity of heat throughout the inside
of the oven than has hitherto been possible.
Although I have only described in the foregoing the manner of applying my
improvements to the heating of an oven yet it will be quite evident that the same
means may be employed with slight modifications, for the drying of clothes, and
other articles, or for other purposes.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed I would have it under-
stood that I do not confine myself to the exact dimensions or details herein
described, or shewn on the accompanying drawings but I declare that what
I claim is
Firstly. The introduction of the casting (A) forming part of the fireplace and the
construction of the firing doorways (P) as hereinbefore described and shewn on
the accompanying drawings, that by means of the shape of the said casting (A)
and the formation and arrangement of the said firing doorways (P) access is given
to every part of the fireplace at once from the outside.
Secondly. Diminishing the amount of surface of the top row of heating tubes,
exposed to the action of the fire, thereby attaining greater equality of temperature
between the top and bottom rows of heating tubes, than has previously existed.
Thirdly. The introduction of a layer of material that will obstruct the trans-
mission of heat, preferably of asbestos, fixed to the backplate (N) in the inside of
the oven in order to keep out any excess of heat from the fireplace, and cause a
greater uniformity of temperature throughout the oven, than has formerly been
attained.
Dated this ofth day of August 1885