Improvements in the Furnaces of Water Tube or Externally Fired Boilers.
Year: 1898

page_text: Date of Application, 22nd Jan., 1898-Accepted, 7th May, 1898
COMPLETE SPECIFICATION.
Improvements in the Furnaces of Water Tube or Externally Fired
Boilers.
We, GEORGE WATSON, of 21, Springfield Mount, in the City of Leeds, Engineer,
the Managing Director of The Horsfall Furnace Syndicate, whose registered office
is at Atheneum Buildings Park Lane, in Leeds, aforesaid, and THE HORSFALL
FURNACE SYNDICATE. LIMITED, above mentioned, 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:--
In the furnaces of water tube boilers whose sides are formed of brickwork
the sides are subject to rapid deterioration and destruction because of the adhesion
of clinker and the subsequent detachment thereof by the stoker or fireman. The
object of our invention is to obviate such deterioration and destruction and at the
same time and by in part the same means to provide a supply of heated air to the
furnace. Our invention is more particularly designed for use in connection with
water tube or externally fired boilers and in the following description and in our
drawings we shall describe it as used with such a boiler. Our invention consists
in providing air chambers of iron or other metal (one on each side of the furnace)
and causing all air required by the furnace for combustion to pass through them.
These air chambers take the shape of boxes corresponding with the length of the
furnace of rectangular cross section built into the side walls of the furnace. The
depth or vertical dimensions of the side boxes are such that the boxes stand partly
above the level of the grate bars and also extend below them and they are provided
with perforations or holes or openings in their lower parts to allow of the egress
of air therefrom to the space beneath the grate bars. We prefer to force the air
for combustion into the side boxes by means of steam jet or other blowers through
openings preferably at one end of the side box the other end being closed but the
air may be drawn in by suction created either by chimney draught or by suction
apparatus between the boiler or furnace and chimney.
In order to provide an easy and economical way of renewing the sides of the air
chambers exposed to the action of the fire we make those parts detachable by the
following means namely we form the side of the box exposed to the fire of detach-
able plates and we prefer to attach these by forming near the top of the box a
wedge shaped flange with the thin edge depending downward but at intervals we
provide ribs from top to bottom to strengthen the box. We use plates of a length
calculated to extend from rib to rib and at the back near the top thereof we form
V shaped grooves. The wedge shaped flange fitting into the V shaped groove
holds the plates in position at their upper edges. They are secured at their
bottom edges by wedges which are preferably formed of thin folded metal placed
between the bottom edges of the plates and the turned up parts of the side boxes
through which the air perforations are formed so as to be elastic to allow for the
expansion of the plates under heat whilst at the same time exercising a vertical
thrust. The sides of the air chambers may be used to support the cross bearers to
carry the vrate bars.

page_text: In the accompanying drawings Fig. 1 is a front elevation of a furnace. Fig. 2
is a sectional elevation. Fig. 3 is a side elevation in section showing the front
portion of a furnace Fig. 4 is a plan and Fig. 5 is a cross section to illustrate the
method of forming and fixing the detachable sides of the air chambers.
A is the furnace and a, a, are the firing doors. B is the ashpit and b, b, b, b, are
doors closing up the front thereof, CC are doors in front of the water tubes D
above the level of the furnace fire. E is the boiler. F represents the grate bars
supported by cross bearers bolted to the sides of the air chambers G, G, G are the
air chambers, G¹, G¹, being the detachable sides, g', g¹ are the ribs supporting
the detachable plates, r, r, are the grooves at the back thereof and W W are the
resilient folded metal wedges holding the detachable sides in position. H H are
tubes or trumpets fitting into the front ends of the air chambers G, G for the
admission of air thereto." h, h, are the front ends of the tubes or trumpets showing
both holes for affixing steam jets not shown in the drawings. J J are the per-
forations in the air chambers on the underside of the grate bars.
Having now particularly described and ascertained the nature of our inven-
tion and in what manner the same is to be performed we declare that what we
claim is:-
1. In furnaces for the heating of water tube boilers the use of air chambers of
iron or other metal for the purposes herein before mentioned and constructed and
placed as hereinbefore, and in the drawings described.
2. In furnaces for the heating of water tube boilers worked with closed fronts
the use of air chambers of iron or other metal constructed in the side walls of such
furnaces with outlet openings therefrom below the grate bars in combination with
a steam jet blower or blowers for the purposes herein before mentioned and as
herein before and in the drawings described.
3. The formation in the sides of a furnace for heating a water tube boiler of
air chambers with detachable sides for the purposes and in manner herein before
and in the drawings described.
4. The general construction and arrangement of air chambers in the sides of a
furnace for heating a water tube boiler for the protection of the sides thereof and
for the supply of air to the furnace substantially as hereinbefore and in the
drawings described.