Year: 1889

page_text: Date of Application, 6th Apr., 1889
Specification Accepted, 18th May, 1889
I, LEWIS HOPCRAFT of 26 West Bank Stamford Hill in the County of Middlesex
Engineer do hereby declare the nature of this invention and in what manner the same
is to be perforined, to be particularly described and ascertained in and by the follow-
ing statement :—
This invention relates to circular self stoking furnace fire grates which are made to
rotate by any suitable means, the fuel being fed from above or below on to the centre
of the rotating grate, the object of this invention being to render the self stoking
more efficient and thereby to increase the combustion of the fuel. And in order that
my invention may be well understood and carried into practice, I will describe the same
with reference to the accompanying drawings in which similar letters are used to
indicate corresponding parts throughout.
Figure 1 is a plan of my improved grate; Figure 2 is a sectional elevation on the
line A B Figure 1. Figure 3 is a plan of one of the circular fire bars; Figures 4
and 5 are enlarged sections on the lines C, D, and E, F respectively of Figure 3,
Figure 6 is an elevation of one of the radial arms G Figures 1 and 2 ; and Figure 7 is
an end view of an arm G with one of the fire bars thereon.
The radial arins G are rigidly affixed to or constructed in one with the shaft or
tube H which is rotated by any suitable arrangement of mechanism. When the grate
is underfed H is hollow and forms the tube within which is the worm conveyer tube
for feeding the grate as is well understood. These radial arms G are vertically
sinuous or sinuous only on their upper surfaces as shewn in Figures 2 and 6, and the
fire bars when placed thereon conform to the wavy shape of the radial arms, the
sinuosities of each of which corresponds to that of the other radial arms, so that when
in position each bar is level. The fire bars J are cast of circular shape and of different
diameters and are placed on the radial arms G concentrically. Each fire bar J except
the outermost is cast with lugs K corresponding to the number of radial arms G, which
said lugs serve to keep the bars a proper distance apart, and provide the requisite
spaces L for air to pass through into the fuel on the grate. The underside of
the lugs K is slotted so as to fit over the radial arms G as shewn in Figure 7. The
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page_text: fire bars J are preferably triangular in cross section for lightness and also to form as
large a passage way as possible for the admission of air to the grate, the lugs being
rectangular in cross section (see Figs. 4 and 5).
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 I claim is :-
(1) The construction of a furnace grate consisting of concentric bars J with distance
pieces or lugs K, fitting by slots over radial arms G with sinuous upper surfaces,
which said arms G are attached to or formed in one with a central rotating shaft or
tube H substantially as and for the purpose herein before set forth and illustrated in the
accompanying drawings.
(2) In combination with a central rotating shaft or tube H, the vertically sinuous
radial arms G for carrying concentric fire bars substantially as and for the purpose
herein before set forth and illustrated in Figures 1, 2, and 6 of the accompanying
drawings.