Improvements in Grates for Steam Boiler and other Furnaces.
Year: 1889

page_text: Date of Application, 14th May, 1889-Accepted. 15th June, 1.39
OMPLETE SPECIFICATION.
Improvements in Grates for Steam Boiler and other Furnaces.
1, CHARLES J. DORRANCE of No. 64 South Jefferson Street in the City of Chicago
and State of Illinois United States of America, Manufacturer, 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 :-
The object of my invention, which relates to that class of grate bars known as
rocking or shaking grate bars, is to simplify and cheapen the construction of such
grate bars and at the same time to produce a rocking or shaking grate which will,
when operated, more thoroughly agitate the fire, separate and loosen the coal, ashes
and clinkers, break up the clinkers, sift out the ashes, and produce a more thorough
and complete combustion of the coal. These and other features of my invention
will be more readily understood by reference to the accompanying drawings, in
which,
.
Figure 1 illustrates in perspective a grate embodying my invention as applied to a
boiler furnace.
Figure 2 illustrates a side view of the grate bars, the supporting frame and boiler
front being shown in section.
Figure 3 is a similar view showing a changed position of the bars or grate sections.
Figure 4 is a rear end view showing the rocking sbaft and connections for
operating the grate bars. In a rocking grate embodying my invention, the grate
bars or sections are each pivoted or journaled in a frame, so that they may be
oscillated or rocked, and the fire supporting surface of the grate is composed of a
number of clips or vertical plates arranged parallel with each other upon cach grate
bar. A main feature of my invention is embraced in a construction in which the
pivots or journals of each grate bar are located at one side of a vertical plane passing
through the center of the grate bars, (when the latter is in its natural or normal
position), so that when all of the bars are rocked a positive up and down motion is
given to the plates or clips as the latter are oscillated while at the same time a
sheering action is produced between adjacent bars which tends to break up the clinkers
resting upon them.
In the practice of my invention, I use one or more grate bars or sections according
to the amount of fire surface required. When more than two grate bars are used
connect together depending arms upon each alternate grate bar by means of bars or
rods, and these in turn are connected with a rocker shaft, (usually placed at the rear
of the grate frame,) so that by rocking or oscillating said rocker shaft all the grate
bars may be actuated.
In the said drawing, A, indicates the frame of a furnace A¹, the front wall or plate
thereof, and B B', the grate bars, which latter are usually placed transversely of the
frame in the manner shown. Each bar has a depending arm, the alternate arms
being lettered B2, B3. At each end of each bar either to the right or left of a line
drawn vertically through the center of the bar, is located a pivot or trunnion &', the
pivots or trunnions at both ends of the bar being located in the same horizontal
plane. The frame A, affords bearings for said pivots or trunnions b¹. C, C¹², are
rods or bars which connect the alternate depending arms B2, B3 of the grate bars.
D, is the rocker shaft provided with arms or lugs D¹. 02, C3, are rods connecting
the bars C, C, with the lugs D¹, on the rocker shaft, one of said rods being
connected above and the other below the rocker shaft, as clearly seen in Figures 2,
3 and 4.
Supported in a suitable bearing on the front plate A¹, is an operating lever E.
Said lever is provided at its upper end with a handle and to its lower end is secured
one end of a connecting rod E', the opposite end of which connecting rod is secured

page_text: to one of the rods C, C. The clips or parallel plates composing the fire supporting
surface are desirably made with convex or rounded upper surfaces and concave sides
or under surfaces. I usually cast or place a projection or rib a, at the ends of the
frame opposite the end grate bars of the series so as to aid the end clips in crushing
the clinkers.
It will be observed that in the operation of my invention when the operating lever
is moyed in one direction, one series of bars (B) will be lowered while at the same
time the series consisting of the alternate bars (B) will be raised, so that the bars
will take the position illustrated in Figure 3. When the operating lever is moved
in the opposite direction the grate bars will assume a position the reverse of that.
shown in said Figure 3. It will also be observed that in moving the lever E, a
positive up and down motion as well as an oscillating and sheering motion is produced
such movement tending to shake up the fire, sift out the ashes, and break or crush
the clinkers. The motion of the grate bars in the manner described also serves to
open and close the spaces between the grate bars or sections, thereby enabling the
ashes and clinkers to pass beneath the bars into the ash-pit.
I prefer to arrange all the trunnions or pivots on the same horizontal plane, in the
manner illustrated.
In the drawing I have shown one end of the connecting. rod E, as attached to the
rod, but it is obvious that said connecting rod may be attached to any one of the
depending arms B B¹, or to one of the arins upon the rocker shaft if desired. For
convenience I have shown the lever E, as attached at about the center of the boiler
front, but said lever may be otherwise located or disposed, as found convenient or
desirable.
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 :-
1-A grate composed of one or more bars pivotally secured to a supporting
frame, with a pivot or trunnion placed on one side of a line drawn vertically through
the center of the bar, and placed in the same horizontal plane, said bars being also
provided with depending arms, substantially as specified.
2: In a grate a series of bars B, B1, provided with pivots or trunnions located on
one side of a line drawn vertically through the center of the grate surface of said
bars, said bars being provided with depending arms B2, B3, two bars C, C¹, one of
which bars is connected with the arms B2, of the alternate bars B, and the other
with the arms B3, of the intermediate bars B1, a rock shaft provided with opposite.
Ings severally connected with the said bars C, C', whereby the alternate grate bars.
will be oppositely moved when the rock shaft is oscillated, and means for actuating
the rock-shaft, substantially as described.
Signed at Chicago, Illinois, D.S.A this 30th day of March A¨D. 1889
CHARLES J. DORRANCE.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, Agents for the Applicant.