Improvements in Steam Generators, and in the Furnaces used in connection therewith.
Year: 1897

page_text: Date of Application, 4th June, 1897--Accepted, 31st July, 1897
COMPLETE SPECIFICATION.
Improvements in Steam Generators, and in the Furnaces used in
connection therewith.
We ALFRED DAVY of 4 Woburn Place London W.C. in the County of London
Engineer and JOHN EDEY of 16 Eastcheap London E.C. in the County of London
Colliery Proprietor do hereby declare the nature of our said invention and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement :-
Our invention has for its object improvements in Grates for Steam Boilers' which
are so constructed that the parts exposed to the action of the fire when at a high
temperature are able to sustain the heat and rapid circulation of the water is obtained
at the same time resulting in considerable economy of fuel and greater boiler.
efficiency with also the possibility of using fuel of an inferior kind.
In order that our invention may be clearly understood and more easily carried
into practical effect we have appended hereunto drawings showing one of our grates
applied to an ordinary double flue boiler which will make its applicability to other
boilers quite simple, and it will be clearly understood that the same may be applied
to a furnace or fire external to any steam boiler and where the waste heat or a
portion of the heat from such furnace is used for other purposes than entirely for the
generation of steam.
Figure 1. is the front elevation of a double flue boiler with fire doors and other
well known boiler fittings not applied or removed therefrom but showing the most
necessary parts of the arrangements of our grate applied thereto.
Figure 2. is a vertical side elevational section through one of the flues F with the
boiler broken off behind the bridge A as regards it length.
Figure 3 is a horizontal sectional plan through the flues F. F.
Figure 4 is a cross sectional elevation through the boiler and fire place behind the
dead plate D showing one kind of water bridge in the right hand flue and another
kind of water bridge in the left hand flue.
Figure 5 shows a broken off section through one kind of bridge.
In the sides of the flues F we fix water plugs S communicating with the water
inside the boiler or instead of two separate plugs we may run a water tube entirely
across the flue under the dead plate D and upon which the dead plate rests and is
quite free to move outwardly or inwardly as the tubular grate bars T'increase or
decrease in length due to expansion and contraction in their length. This dead
plate may be a hollow casting of steel or it may be built up in plates but in any
case the front ends of the tubes T are connected with the insides of the dead plate D
and bridge A by watertight junctions and the dead plate is free to slide upon the
water studs S or their equivalent cross tube before mentioned. The water bridge A
may be made in one part or built up with the flue F as shown in elevation in the
eft hand flue Figure 4 or it may consist of a hollow separate piece as shown in
front elevation in the right hand flue Figure 4 and in side elevation at Figure 5 in
which case a branch a shown partly in section communicates with the boiler
hrough the passage a' being hung or suspended from the flue F by the flange a³
but in any case the water has free access to the inside of the water bridge and

page_text: thence to the hollow tubular bars T through which it freely circulates to the dead
plates D.
It will be evident that the bridge A may be made in a number of designs
and shapes to suit the purpose but when applied to boilers already at work we prefer
to fill in the spaces a', a with fire bricks or blocks of fire clay and when necessary
to build the front of the bridge up between the part as of the bridge and the top
of the flue F to prevent the flames or heat passing. the bridge at the upper portion
of the flue, but when the bridge is built up as a portion of the boiler flue F as
shown in the left hand flue Figure 4. this may not be necessary. We have already
intimated that the tubes T which we prefer to make from solid weldless steel tubes
are connected with watertight joints to the bridge. A and to the dead plate D so
that the water in the boiler is free to circulate through the tubes T forming the fire
grate from the bridge to the dead plate. Two or more of these tubes are preferably
used as longitudinal stays between the bridge A and the dead plate D to withstand
the pressure endwise between the two. At the front of the hollow dead plates D
branch pipes 2 and 3 communicate with the interior of the dead plates and then
through the pipes v4 and through the valves V and V₁ with the interior of the
boiler or other steam chamber so that a constant circulation is set up and maintained
from the boiler through the branches a² of the bridges through the bridges A and
along the tubular bars T and the dead plates D and pipes v' and v³ and valves or
cocks V and V₁ into the front end of the boiler. The central valve box W is set
below the line of the pipes and v-so that when the valve of the valve box. W is
closed the communication is quite clear above it, but when, the valves V and V' are
closed and W is open the dead plates D tubular bars T and bridge A are thoroughly
blown through and cleansed the accumulation deposit if any being carried down the
pipe w into the drain. It must be understood that the dead plates D are always
free to move with the expansion of the tubular bars T and for this purpose the
pipes and may be made of copper or have bends or flexible joints or junctions
in connection therewith to allow of such freedom of movement with sufficient
stability coupled with sufficient flexibility of the parts. We have said that the dead
plates slide upon the round studs S or equivalent tubes but friction ferrules or
rollers may be mounted upon such studs or tubes to facilitate such movement with
freedom. The tubular bars if long may be supported across the centre or other part
of their length by a cross water tube S₁ or more than one such support.
The operation of the furnace is as follows:-
When the fire is made the deflection plate K which may be hinged or removable or
fast deflects the inlet air upon the surface fuel and all, the smoke and gases are
carried by the draft downwards through the fire-as they cannot pass the bridge on
a level with or above the fire-in the direction of the arrows-and then turning
upwards as they pass onwards along the flues. The bottoms f¹ of the flues F are
thus utilized as beating surface and a most intense heat is maintained in the fire
boxes and the flues without making any smoke even when inferior fuel is being
used. The dead plate D in the case of a flue Boiler should be made as thin in depth
as practicable and the pipes v¹ and v5 are so arranged in regard to their area as to be
equal or about equal to the combined sum area of all the tubular bars T.. It is also
necessary to so arrange the sizes and thicknesses of these parts that doors fitted above
the dead plate and below the dead plate so as to close up the front of the flues may
be easily operated without impediment to their free action. We generally find that
cocks are more compact for the front pipes than valves. Expansion and contraction
may be provided for at the bridge by making the connection or pipe a¹ of copper or
of such a shape as to allow of a limited movement.
Having now particularly described and ascertained the nature of our said
invention we declare that what we claim is :-
-
CLAIMS.
First. The improvements in grates for steam boilers or for furnaces in conjunction
with steam boilers or vessels consisting of a suspended or hollow bridge and dead
plate with tubular or hollow bars mounted between the bridge and dead plate with
+

page_text: provision for the free movement of the dead plate or the bridge and with
communication through pipes at the front for the free circulation of the water
through the arrangement substantially as herein set forth and shown upon the
accompanying drawings.
Second. In circulating grates the use of circulating cocks or valves V and V₁ with
their pipes v and 5 and the blow off cock or valve W as and for the purpose herein
set forth and shown.
Third. In circulating grates the mode of supporting the dead plate upon water
studs or their equivalents to allow for freedom of expansion and contraction in the
bars.
Fourth. In circulating grates the mode of hanging the bridge with a flexible neck
or its equivalent substantially as and for the purpose set forth.
Fifth. The improvements in the grates for steam boilers substantially as set
forth and as shown upon the drawings.
:
Dated this 3rd day of June 2007
GEORGE BARKER,
77 Colmore Row, Birmingham, Agent for the Applicants.