Improvements in and connected with Mechanical Stokers.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in and connected with Mechanical Stokers.
We, JOIN VICARS, the Elder, THOMAS VICARS, and JOHN VICARS, the Younger,
all of 56, Seel Street, Liverpool, in the County of Lancaster, Engineers, do hereby
declare the nature of this invention to be as follows:-
The objects of this invention are:-
First. To provide means, whereby, whilst preserving a certain minimum fixed
and regular travel of the fire bars, such travel may be extended as required.
Second. To so construct the doors and air ways in front of the furnace and
the sill plate at the rear of the furnace that such parts shall not be liable to be
cracked or distorted by unequal expansion or contraction, and, that the air to
support combustion shall be distributed in the most convenient way to ensure
certain and complete combustion.
Third. To so construct the fire bars that the rear portions of such fire bars may
be easily renewed when worn independently of the front portions.
For these purposes:-
First. We make the teeth or projections on one set of yokes or keys, by means
of which forward travel is given to all the fire bars, adjustable by means of rack
and pawl or other suitable gear, so that such travel can be varied, and we form
the second set of yokes or keys which give the backwards motion to the second
set of alternate bars with shoulders or projections which bear against cams on
the driving shaft so as to prevent the second set of bars moving back, by reason
of friction between them and the first set, more than a certain distance until
such cams by the rotation of the driving shaft become free from the said shoulders.
The complete return of the second set of bars is effected by dogs acting against
teeth or projections on the second set of yokes in the usual way.
Second. The airways at each side of the door of a furnace are formed as cham-
bers projecting under the openings through which the fuel is fed into the furnace,
and the ends of such chambers are made with deep indentations so as to form a
kind of comb through which and also under the sides of the chambers the air
is admitted to the fuel at the most suitable points for certain combustion thereby
preventing waste by small fuel dropping unburnt through the fire bars, and
ensuring the fire being kept in good condition. The air in passing through the
chambers and combs becomes heated to some extent and also cools the chambers
thus preventing cracking or distortion by unequal expansion. The lower edge
of the furnace doors and the rear of the sill plates over which the nearly
consumed fuel is pushed are also formed with deep indentations through which
air is equally distributed, in one case to the front of the fire, and in the other
to the nearly consumed fuel as it leaves the fire bars, thereby ensuring perfect
combustion. The indentations also prevent the doors and sill plates being
cracked or distorted by unequal expansion.
Third. We form the fire bars each in two portions joined together by projec-
tions fitting into recesses, and we provide a support at or near the junctions of

page_text: the bars thus allowing of the rear portions of such fire bars being removed and
replaced without disturbing the front portions.
We, JOHN VICARS, the Elder, THOMAS VICARS, and JOHN VICARS, the Younger,
all of 56, Seel Street, Liverpool, in the County of Lancaster, Engineers, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, reference being had to the accompanying drawings:-
-
The objects of this invention are First. To provide means whereby, whilst
preserving a certain minimum fixed and regular travel of the fire bars, such
travel may be extended as required.
Second. To so construct the doors and airways in front of the furnace, and
the sill plate at the rear of the furnace that such parts shall not be liable to he
cracked or distorted by unequal expansion or contraction; and that the air to
support combustion shall be distributed in the most convenient way to ensure
certain and complete combustion.
Third. To so construct the fire bars that the rear portion of such fire bars may
be easily renewed when worn independently of the front portions.
For these purposes. First. We make the teeth or projections on one set of
yokes or keys, by means of which forward travel is given to all the fire bars
adjustable by means of rack and pawl or other suitable gear so that such travel
can be varied, and we form the second set of yokes or keys which give the back-
wards motion to the second set of alternate bars with shoulders or projections
which bear against cams on the driving shaft so as to prevent the second set of bars
moving back, by reason of friction between them and the first set, more than a
certain distance until such cams by the rotation of the driving shaft become free
from the said shoulders. The complete return of the second set of bars is effected
by dogs acting against teeth or projections on the second set of yokes in the usual
way.
Second. The airways at each side of the door of a furnace are formed as cham-
bers projecting under the openings through which the fuel is fed into the furnace,
and the ends of such chambers are made with deep indentations so as to form a
kind of comb through which, and also under the sides of the chambers, the air
is admitted to the fuel at the most suitable points for certain combustion thereby
preventing waste by small fuel dropping unburnt through the fire bars, and
ensuring the fire being kept in good condition. The air in passing through the
chambers and combs becomes heated to some extent, and also cools the chambers
thus preventing cracking or distortion by unequal expansion. The lower edge
of the furnace doors, and the rear of the sill plates, over which the nearly
consumed fuel is pushed, are also formed with deep indentations through which
air is equally distributed, in one case to the front of the fire, and in the other
to the nearly consumed fuel as it leaves the fire bars, thereby ensuring perfect
combustion. The indentations also prevent the doors and sill plates being
cracked or distorted by unequal expansion.
Third. We form the fire bars each in two portions joined together by projec-

page_text: tions fitting into recesses, and we provide a support at or near the junctions of
the bars thus allowing of the rear portions of such fire bars being removed and
replaced without disturbing the front portions.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 is a longitudinal sectional view. Fig. 2 is a plan view, and Fig. 3 is
a sectional detail view all illustrative of the first and third parts and part of
the second part of our invention. a a aro yokes or keys a pair of which are
arranged at each side of each furnace and secured to the cross bearers 6 b¹ respec-
tively, by means of which to and fro motion is given to the fire bars cc in
the usual way, the bearer 6 moving the whole of the bars forward, and then
drawing back alternate bars c, the bearer 61 afterwards drawing back the second
set of alternate bars c¹. The yokes or keys are actuated by dogs or projections
on the driving shaft acting against teeth or projections on
the yokes
or keys in the well known way. e are shoulders on the keys a¹, which
shoulders, during the time the first set of bars c are being moved back rest
against the cams f on the shaft and prevent the second set of bars c¹ being
completely moved back, until such cams, as the shaft d rotates, are freed from
the shoulders e; the keys a¹ are then free to be moved back by the dogs on the
shaft d in the usual way, carrying with them the second set of bars c¹. In
this way during a certain portion of the backward travel the bars must move
alternately. In order to allow of a greater travel being given to the fire bars
when desired we attach the teeth g of the keys a (see Fig. 3) to the bars h free
to slide in guides in the keys a and secured in position by pawls i taking into
racks on the bars h. kare the dogs on the shaft d which act against the
teeth to give the forward motion to the keys a and thereby to the whole of
the fire bars. By drawing out the bars h in the direction of the arrow, a greater
travel is given to the fire bars. To give the return motion to the first set of
bars the dogs act against the teeth 7 on the keys a, and to give the return
motion to the second set of bars c¹, dogs act against teeth on the keys a¹.
When forward travel is given to the fire bars greater than is sufficient to
move the shoulders e clear of the cams f, the second set of bars c¹ is free to travel
backwards with the first set e till the shoulders e come against the cams f, if
the friction between the bars and is great enough, but for the remainder
of the backward travel the bars move alternately by reason of the cams f stopping
the bars until the bars e have reached the end of their backward travel. If the
friction between the bars cand e is not great enough to cause them to move
together the whole return motion of the bars is caused by the dogs k acting
against the teeth on the keys a' as above described.
The fire bars are each made in two portions joined together by projec-
tions s fitting into recesses t so that the rear portions can be renewed inde-
pendently of the front portions, u are V joints for preventing lateral displace-
ment, is a bar or support attached to the sides of the furnace for supporting
the fire bars at the junction of the front and rear portions, in is a bar for sup-
porting the back end of the rear portions.
Fig. 4 is a front view. Fig. 5 is a longitudinal sectional view. Fig. 6 is a
cross sectional view at the line A A on Fig. 5, and Fig. 7 is a horizontal sec-
tional view at B, B, on Fig. 5 all illustrative of the second part of our invention.
The airways at each side of a furnace are formed as chambers m projecting
under the fuel feed openings n. o are indentations in the ends of the cham-
bers m forming a kind of comb through which air passes to the fire just at the
point the fuel is fed into the furnace, the air becoming heated on its way and
ensuring efficient combustion. Air also passes to the fire under the sides m
of the chambers. The lower edge of the furnace door p is also formed with
indentations through which air passes to the front of the fire. Referring to
Figs. 1 and 2 is the sill plate at the rear of the furnace over which the nearly

page_text: consumed fuel is pushed by the moving fire bars. rare indentations in the sill
plate through which air is equally distributed to the mass of nearly consumed
fuel thus ensuring complete combustion. By making the doors, airways, and
sill plates with indentations as above described the parts are free to expand
and contract without any liability to cracking or distortion of the general form,
and at the same time the air supply is sufficiently distributed and heated.
The arrows show the direction of the currents of air.
Having now paticularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is:-
First. In mechanical stoking apparatus the combination with appliances for
giving varied travel to the fire bars whilst preserving a fixed minimum alternate
backward travel of chambered and indented airways, indented doors and sill
plates, and of fire bars made in two portions and supported at the junction sub-
stantially as and for the purposes described.
Second. Appliances whereby a varied travel may be given to the fire bars of
mechanical stoking apparatus whilst a fixed minimum alternate backward travel
is preserved substantially as described.
Third. In mechanical stoking apparatus chambered and indented airways,
indented doors and sill plates, substantially as and for the purposes described.
Fourth. In mechanical stoking apparatus fire bars made in two portions and
supported at the junctions substantially as and for the purposes described.
Dated this Fifteenth day of August 1898.
W. B. JOHNSON,
4, Clayton Square, Liverpool, Agent.