Year: 1893

page_text: Date of Application, 4th Aug., 1893-Accepted, 23rd Sept., 1893
My improvement comprehends certain features in the construction of shaking
grate bars adapted to steam boiler work more particularly, whereby they may be
made of great length and by the impartation of a rocking motion be operated at
the center as well as at the ends to secure the combined rocking and transveise
shifting movement capable of breaking down the clinkers and cleaning the grate
of ash and cinders. My invention also comprehends certain specific improvements
in the details of construction which will be fully described when referring to the
drawings, in which :
Fig. 1 is a plan view of a fire grate embodying my invention;
Fig. 2 is a side elevation of same;
Fig. 3 is a cross section of a portion of the grate bars on line y-y of Fig. 2;
Fig. 4 is a cross section of the grate bar and upper part of the center bearer
adjacent to the line - of Fig. 2;
Fig. 5 is a plan view of the middle portion of one of the grate bars;
Fig. 6 is a longitudinal section on line w-w of Fig. 5;
Fig. 7 is a front elevation of the center bearer bar; and
Fig. 8 is an elevation of the front and rear bearer bars.
The grate is made up of a series of parallel grate bars A supported at each end
by bearer bars B and C, and also preferably at the middle as by a central bearer
bar D.
The bar A is made flat on its top transversely considered but is formed with a
series of transverse grooves E which meet to form transverse ridges e excellently
adapted to support the coal and permit the ready admission of air to it during
combustion, and also to act at the corners as knives for breaking down cinders or
clinkers when rocked to clean the fires. The cross section of the bar is essentially
of inverted U shape, the sides being preferably at right angles to the top, and
projecting downward to form girder webs F, F. The upper edges of these webs
are preferably thickened as at so as to give more clearance at the lower part
between adjacent bars to insure easy clearance of ash and cinders, and also to form
a liberal passage for air for combustion, or in other words forming a funnel shape
whereby it causes the air to ascend with greater force. Opening downward through.
the curved upper surfaces or grooves E are numerous apertures H of larger
diameter at the bottom, where they open between the webs F, then at the top, as
is necessary for self clearance. These apertures are preferably so disposed that
This
two parallel apertures come in one groove and one in the next and so on.
properly distributes the air through the grate. The grate is reinforced or
strengthened by a series of transverse corner ribs G on the under or inner part of
the bar which perform the dual purpose of strengthening the top of the bar and
also its webs, and at the same time do not interfere with the air passage running
longitudinally between the webs which materially acts to equalize the air supply to
the apertures and also to increase in a given time the hot air actually delivered to
the fire.
The under side of the bar at front, rear, and center is formed with bearings I,
polygonal in cross section having three or more flat surfaces arranged at an angle
to each other and adapted to front, rear, and center bearer bars B, C, and D,

page_text: respectively, which have projections formed in cross section to approximately fit
the polygonal shaped hearings I. The front and rear bearer bars have their
projections J extending laterally from vertical transverse bars or plates, while the
center bearer bar D has its bearer projections extended upwardly between the
webs of the bars. These projections are preferably of greater transverse width
at the top than at the bottom so as to permit free rocking of the webs of the bars
in the spaces between adjacent bearers J. It is evident that in those cases where
the bar is short, as in small furnaces, the center bearing and bearer bar may be
omitted.
The forward end of the bar is provided with a crank arm K connecting with the
body of the bar just back of the front bearing I and so as to extend forward below
the front bearer bar A, whereby the several bars may be independently rocked.
I have, after a most extensive use and thorough practical test of these improved
bars, found that not only do they enable a clean and bright fire to be maintained,
but entail less labor on the stoker than with any bars which my experience bas
brought to my notice. The advantages in the employment of the center bearer are
most important, as prior to the use of this part of my improvement, I found great
difficulty in the case of long bars from sagging or breaking down altogether when
overheated and overloaded. The sagging was very injurious in that it prevented
the proper rocking of the bars and the maintenance of a clear and clean fire by
the proper breaking down and removal of clinkers. Furthermore, by the proper
use of the straight transverse top to form right angled edges at the sides I am
enabled to positively cut or break the clinkers by allowing them to lie against the
side face of the adjacent bar and forcing the sharp corner of the edge e through
them.
While I prefer the construction shown, the minor details may be somewhat
modified without departing from my invention.
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 :
First. The grate bar substantially as herein described and shown.
Second. The bearer bars having projecting bearers formed with polygonal shaped
upper parts adapted to the said grate bars.
Third. A grate bar of inverted U shaped cross section having its surface formed
with grooves between the ridges e and with downwardly opening apertures.
Dated this 6th day of July 1893.
FRANK JAY ST. JOHN.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.