IMPROVEMENTS IN AND IN CONNECTION WITH TRAVELLING GRATES. FOR FURNACES
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by George Ashworth and Elijah
Ashworth at the Office of the Commissioners of Patents on the
22nd November 1882.
GEORGE ASHWORTH and ELIJAH ASHWORTH of the firm of Ashworth Brothers
of the City of Manchester in the County of Lancaster,
IMPROVEMENTS IN AND
IN CONNECTION WITH TRAVELLING GRATES. FOR FURNACES
"
"
Our Invention relates more particularly to the apparatus for which Letters
Patent bearing date the twenty-seventh day of March in the year one thousand
eight hundred and eighty-two and numbered 1470 have been granted to James
Hodgkinson. In the said apparatus an endless chain of grate bars was set in
motion so that the grate surface travelled towards the back or the front of the
furnace the chain of bars being carried by and travelling upon two cast iron bearers
upon which were formed side gratings which formed stationary portions of the
general grate surface. As the sides of the bed of fire rested upon the said side
gratings these parts of the said bearers became highly heated and the lower parts
of the same bearers being much less heated through not being so directly exposed
to the fire the bearers became distorted whereby the efficient working of the grate
was interfered with and the said bearers generally cracked and had to be replaced
after being in use a comparatively short time. To remedy these defects is the
principal object of the first part of our Invention. We form the side gratings
separately from the bearers and in lengths which rest upon projections from the
bearers. A length of grating which may become cracked or burnt can be replaced
without having to replace or even to remove the bearer. Spaces are provided for
the flow of air between the fixed and the moving gratings the air being brought
into contact with the upper edges of the bearers which are not in contact with the
bed of fuel. The moving grate bars when in their upper positions slide upon the
upper edges of the bearers or upon ledges or bars, projecting from or attached to
the bearers. When returning the grate bars slide upon the edges of bars which
are attached to cross rods and the ends of the said rods rest in recesses formed in
lugs which are formed upon or secured to the bearers. The driving shaft is fitted
to revolve in blocks which slide in the outer ends of the bearers but are free to
accomodate themselves to the shaft each block being set up by means of a set-screw
which bears against the back of the block. To check the admission of cold air at
the furnace front we use a yielding plate or roller which latter may or may not be

page_text: driven such plate or roller partly closing the space below the furnace doors and
rising when necessary to permit the passage of clinkers or cinders. We also apply
a curved shield or plate which covers the front end of the grate and directs the
falling matters into a receptacle. To remove adhering matters we use a fixed
or yielding scraper or a moving scraper or a revolving toothed roller or a revolving
clearer. In some cases we mount the side gratings so that their sides are clear of
the bearers and furnace flues and sustain them by means of end trunnions which
rest in bearings so that whenever it is desirable to clear a side grating it may be
tilted up or be inverted. We may arrange for the axis of motion to be at-or-near-
-the-inner edge of the side grating in which case the grating could be tilted up or
inverted so as to discharge the matters resting upon it on to the travelling grate.
A second part of our Invention relates to the arrangements for actuating the
moving grate. We connect the upper driving apparatus with the lower driven
parts by means of a wire or of a connection which will break with a strain which
is greater than the ordinary working strain in order to prevent the breakage of
parts which cannot be repaired or replaced so readily and cheaply as a length of
wire. The excentric used in the former Invention caused the grate to be moved at
comparatively long intervals. We prefer to move the grate to a lesser extent at
each movement and at shorter intervals. We employ a wiper cam or stud-wheel
which acts upon a lever a number of times during one revolution and we connect
the said lever with the pawl lever or with a lever which carries a dog which
alternately slips and holds upon a plain wheel as the lever vibrates to and fro.
We prefer to connect the two levers by means of wire for the reasons herein before
given.