Improvements in or appertaining to Fire Bars for Boiler or other like Furnaces.
Year: 1891

page_text: Date of Application, 13th July, 1891
Complete Specification Left, 13th Apr., 1892-Accepted, 14th May, 1892
PROVISIONAL SPECIFICATION.
Improvements in or appertaining to Fire Bars for Boiler or other
like Furnaces.
I, ALEXANDER MURRAY of 14 Thakeray Street, Liverpool in the County of
Lancaster, Engineer Harrison Line, do hereby declare the nature of this invention
to be as follows:-
-This invention relates to fire bars for steam furnaces and the like and to means
for operating the same and it has for its object a novel arrangement whereby the
fire bars can be kept free of clinker without many of the disadvantages attending
some of the forms of self cleaning fire bars at present in use.
In carrying my invention into effect I arrange the fire bars transversely to the
furnace the ends resting on bearers at the sides thereof. The bearings of the bars
are curved or rounded in such manner that each bar is capable of rocking to and
fro about its longitudinal axis. Below the bars 1 arrange a rotating or oscillating
shaft or shafts each provided with a series of cams, pins, or projections Bo disposed
upon it that the cams or their equivalents project between the bars. The shape
and arrangement of the cams is such that as the shaft is rotated or oscillated the
bars of each pair of bars are alternately swung towards and away from each other
so that the bar spaces are alternately more or less opened and closed thus keeping
them perfectly free of clinker and permitting dust etc. to fall through.
The shaft or shafts may be operated by any suitable mechanism from the rear or
front of the furnace or otherwise as desired.
The bars may be used with the ordinary furnaces provided with bridges or in
the case of boilers arranged with a common combustion chamber and fired from
opposite ends the bars may run from the front end of one furnace across the
combustion chamber to the front end of the other.
DAL: AL 1
WM. P. THOMPSON & Co.,
6, Lord Street, Liverpool, Patent Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in or appertaining to Fire Bars for Boiler or other
like Furnaces.
I, Alexander MURRAY of 14 Thackeray Street, Liverpool in the County of
Lancaster, Engineer Harrison Line 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 marine boiler furnaces at the present time, where the greatest amount of
power has to be obtained in the smallest practicable space, movable fire-bars have
becomo almost a necessity. The difficulty with these bars, however, is that they
cause intense heat in places, and are thus very apt to melt and run together, and
on any lowering of the temperature they set solid and cau no longer be moved.
Furthermore, as they are generally made to deliver the clinker at the back end, it
is a very sovere labour to get the clinker out of the ash-pit; much loss of heat in
also entailed in cleaning.
Now this invention has for its object a novel arrangement of movable fire-bars
for steam furnaces and the like by which the clinker is removed from the fire all
over the grate whereby the fire-bars can be kept free of clinker without many of

page_text: !
the disadvantages attending some of the forms of self cleaning fire-bars at present
in use.
The invention may be understood from the following description, reference being
had to the accompanying drawings, in which
Figure 1 is a plan of the bars;
Figures 2 and 3 front and side elevations
;
Figure 4 an enlarged view of the device for operating the bars;
Figure 5 a cross section of the bearers for carrying the bars; and
Figure 6 a general view of the fire grate.
In these, AA are a series of transverse fire-bars, extending the entire length of
the furnace. They are broad at the upper surface, and taper down to a compara-
tively sharp edge below. The ends of these bars rest on bearers B provided with
.circular grooves in which the bars are capable of rocking about their longitudinal
axes. Below the bars, I arrange a rotating or oscillating shaft C provided with a
series of cams or circular wedge shaped lugs 80 disposed upon it that the cams or
their equivalents project between the bars. This shaft has only a limited circular
motion. E is a crank for working the bars either periodically or continuously.
The shape and arrangement of the cams D are such that as the shaft is rotated or
oscillated the bars of each pair of bars are alternately swung towards and away
from each other so that the bar spaces are alternately more or less opened and
closed. This is effected in the following mauner, as the crank E is worked one
set of wedge-shaped cams or the other rise up between the fire-bars, one set rising
between the first and second, the third and fourth, fifth and sixth fire-bars, etcetera,
⚫tlie other set rising between the second and third, fourth and fifth, etcetera. As the
cams rise between the two-firo-bars they press their lower edges apart. Thus, cams
rising between bars one and two, and between three and four, press the lower edges
of each of these couple of bars apart, but their upper edges move towards each
other. At the same time the edges of bars two and three rise and recede from
cach other, the projecting clinker slips in between bars two and three, and, as in
the rocking of the rod C the first set of cams fall and the second rise, they again
press the lower edges of bars two and three apart, causing their upper edges to
descend and approach each other, cutting off the clinker between them, and allowing
it to fall into the grate.as a shower of small pieces. In this way the lower surface
of the clinker is continually being stirred, crushed and allowed to fall as a coarse
dust into the ashpit, whence it can be removed at leisure. Therefore, while the
passage of air is constantly kept open, or periodically opened all over the furnace,
the live coals are kept by the clinker from contact with the grate, consequently,
the latter is not burned and melted, as is frequently the case with other movable
fire-bars, and the cleaning and opening is uniform throughout. In sweeping the
tubes, when the soot falls on the fire it very quickly passes through the grate,
owing to this action, instead of the central fire being nearly damped out by the soot
for a considerable time, as is usually the case. A furnace supplied with these fire-
.bars, therefore, need not be cleaned out in the usual manner, as the refuse is being
continually cut away and deposited in the ash-pits.
The shaft may be operated by any suitable mechanism from the rear or front of
the furnace or otherwise as desired.
The bars may be used with the ordinary furnaces provided with bridges, or in
the case of boilers arranged with a common chamber and fired from opposite ends,
the bars may run from the front end of one furnace across the combustion chamber
to the front end of the other.
The bars can easily be removed from the bearers B by removing the sliding
tongue piece F. A convenient way of securing the cams to the shaft C is by
means of the arms G (Figure 4) which pass right through the shaft and are then
secured by uuts.
It is evident that as an alternative the bars could work on pivots and
more than one shaft could be used for oscillating the bars.

page_text: 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 improvement in fire-bars for furnaces, which consists in a series of bars
arranged so as to be capable of rotary oscillating in their axes, and in providing
them with a device capable of rotating alternate bars, so that the upper surfaces or
edges of each pair of bars shall alternately swing towards and away from each other
whereby the bar spaces are more or less opened or closed and the clinker is con
tinually being stirred, orushed, out and allowed to fall as a coarse dust, substantially
as described.
2. The general combined arrangement or construction of parts substantially as
Dated this 12th day of April 1892.
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Nottingham, and London, Patent Agents.