Improvements in Furnace Doors.
Year: 1895

page_text: Date of Application, 12th Mar., 1895
Complete Specification Left. 11th Dec., 1895-Accepted, 18th Jan., 1896
PROVISIONAL SPECIFICATION.
Improvements in Furnace Doors.
ALBERT EDWARD ALLISON 26 John Candlish Road Sunderland County of
Durham Engineer do hereby declare the nature of this invention to be as.
follows:-
My invention relates to new or improved method of working boiler furnace
or other fire doors & is specially designed for marine purposes as the motion of
ships cannot in any way interfere with its working & it can be easily worked by
hand or by pushing lightly with firing shovel. To accomplish my purpose I have
designed a vertically sliding door worked by means of a cranked lever mounted
on gudgeons projecting at top of each side of door frame, pin of crank lever-
working in raidial slots fixed on & projecting from door so arranged that in the
upward motion the baffle plate may clear the top of door frame inside, then
turning the cranked lever which is weighted according to door the door takes
a vertical motion until half open then the above mentioned slots come into action
again & cause it to take an eliptical motion outward, this never allowing the top.
of door to rise over half its own height when thrown full open.
Dated this 11th day of March 1895.
ALBERT E. ALLISON...
I, ALBERT EDWARD ALLISON of 26 John Candlish Road, Sunderland, in the-
County of Durham, 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:-
This invention relates to a new or improved method of working boiler furnace
or other fire doors and is specially designed for marine purposes because the
motion of the ship cannot cause the door to fly open and moreover the door
even when open occupies comparatively very little space.
I will describe my improvements with reference to the accompanying drawings
in which Figure 1 shows a front elevation, Figure a sectional elevation (shut) on
line X Y in Figure 1 and Figure 3 a like view (open) and in the following
description like marks of reference designate like parts.
Referring to the drawings A. is the flat fire door with the usual internal baffle J.
Upon the face of the door 1 rivet or otherwise secure a radial projection B (or if
necessary I may employ more than one) with slot b through which is passed the
cross shaft C. At both ends of this I fix cranked levers D D the shafts E E of
which are carried in side bearings G G. On the ends of said shafts E are
arranged counterweights I which in their normal position lie at or about the angle
shown in Figure 2 to balance the weight of the door in any position and to some
extent nullify the ship's motion thereupon.
By pulling outwards the balanceweights 1 I or either of them the cranks D D-
are turned on their centres E E thereby causing the shaft C to operate on the-

page_text: upper internal surface of the slot 6 and thus first pull the door into the position
shown in dot and pick lines in Figure 3 whereby the baffle plate J is moved clear
of the edge of the fire hole. On further turning the cranks D D the door A is to
a certain degree firstly vertically raised and then moved in a more or less elliptical
and outward direction clear of the fire hole so that free access to the grate is
given.
During the latter movement the door is preferably supported on the convex
surface d of the cranks D, its final position being determined by the inner lower
edge coming into contact with the stops or projections K on the door frame H
and so preventing the revolution of the cranks, (see Figure 3).
In places where space is a consideration I may employ straight cranks or cranks
without the curved surface or arm d but I prefer the construction herein shown.
For closing the door the motion is simply reversed.
On each counterbalance weight II provide an extension or lug L which is
intended to work or revolve against the outer edge of a boss N of the bearing G
so as to prevent the shafts E being lifted in their bearings except when the door
is fully open as shown in Figure 3.
Instead of manipulating the door as described and to enable it to be operated
by means of a shovel or like tool I may for convenience provide projection M
by which the necessary movement can be effected.
Fire doors constructed as herein described can be opened to their full or any
required extent in less space than hitherto and any position is maintained by
the balance weights II whereby the injurious action of a large inrush of cold
air to the furnace is in great part avoided and also more protection is afforded the
firemen.
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. A furnace door characterised by the arrangement upon its face of one or more
slotted radial projections B through which works a cross shaft C fitted at both ends
with cranked shafts carried in side bearings and provided with balanceweights
whereby the door can be opened and closed in the manner above stated or main-
tained in any desired position the whole being arranged substantially as and for
the purposes herein described and illustrated in the annexed drawings.
2. The general arrangement or combination of parts for opening and closing
furnace doors and for maintaining them in any desired position substantially as
herein set forth.
Dated this 10th day of December 1895.
A. CRAWHALL CHAPMAN,
3 St. Nicholas Buildings, Newcastle-upon-Tyne, Patent Agent.