Improvements applicable to Steam Boiler Furnaces.
Year: 1897

page_text: Date of Application, 17th May, 1897
Complete Specification Left, 16th Feb., 1898-Accepted, 7th May, 1898
PROVISIONAL SPECIFICATION.
Improvements applicable to Steam Boiler Furnaces.
I, JESHURUN COULTHURST, of Robert Street Foundry, Darwen, in the County
of Lancaster, Engineer, do hereby declare the nature of this invention to
be as follows:-
The object of this invention is to provide simple automatic means for shutting
off the admission of air to steam boiler furnaces, at a certain definite period after
the closing of the furnace door after firing up. The invention is applicable in the
first place to such furnace doors as are provided with grids or slots through
the doors, which are opened and closed by means of sliding plates, the opening
of the slots or grids being effected by the act of opening the furnace door; and
the means which I propose to employ for such automatic opening and closing of
the grids is water under pressure from the ordinary town supply or other convenient
source.
For the purposes of my invention I attach to the hinge of the furnace door a
vertical spindle, the upper end of which has attached to it (or formed with it)
a conical plug tap provided with admission and exit openings.
This tap is in connection with the ordinary town pipes or other convenient
source for the supply of water under pressure. The plug tap is opened and closed
by the opening and closing of the door of the furnace to the hinge spindle of
which it is attached as previously mentioned.
When the tap is opened, by the opening of the furnace door, the water under
pressure is admitted by the said tap into the lower end of a vertical cylinder in
which works a piston preferably provided with a cup leather, but it may be other-
wise suitably packed.
To this piston is attached a plunger or rod passing out through the top of the
cylinder and as the piston is raised by the water, the upper end of the said rod
acts upon a bell crank lever, the horizontal arm of which is weighted. The hang-
ing arm of the said lever terminates in a segmental jaw or fork which embraces a
stud or projection attached to the slide which closes or opens the slots or grid in
the furnace door.
The operation of the apparatus is as follows:
The opening of the furnace door turns the plug of the valve and admits the
water beneath the piston which is forced upwards in the cylinder and in rising
lifts the weighted end of the bell crank lever, and causes its other or jawed arm
to open the air admission slides in the door. The further turning of the plug
when shutting the door then opens a small exit orifice in the tap, and the water
commences to escape slowly allowing the weighted end of the bell crank lever
to descend gradually.
The width of the fork or jaw at the lower end of the arm is such that there is
no action whatever on the slide until a certain quantity of the water (say about
two thirds or more) has escaped, and by this time the other side of the fork or jaw
comes against the projection or stud on the slide and commences to close the

page_text: same so as gradually to shut off the admission of air through the grid or grids,
and to close the same entirely by the time that all the water has escaped.
By adjusting the width of the jaw or fork the apparatus can be caused to shut off
the air, supply automatically at any given or desirable time after the closing of the
furnace doors, and this also may be further regulated by providing the exit
opening with an adjustable stop tap.
Dated this 15th day of May 1897
GEO. DAVIES & SON,
Agents for the Applicant, 4, St. Ann's Square, 'Manchester.
COMPLETE SPECIFICATION..
Improvements applicable to Steam Boiler Furnaces.
I, JESHURUN COULTHURST, of Robert Street Foundry, Darwen, in the County
of Lancaster, Engineer, 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 this invention is to provide simple automatic means for shutting
off the admission of air to steam boiler furnaces, at a certain definite period after
the closing of the furnace door after firing-up.
The invention is applicable to such furnace doors as are provided with grids or
slots through the doors or the casing thereof, which are opened and closed by means
of sliding plates, the opening of the slots or grids being effected by the act of
opening the furnace door, and the means which I propose to employ for the auto-
matic opening and closing of the grids is water or other fluid under pressure,
preferably water from the ordinary town supply or other convenient source.
The manner of carrying my invention into practical effect will be readily
understood on reference to the two sheets of drawings hereunto annexed and the
following explanation thereof.
On Sheet 1 of the drawings, Fig. 1 is a partial end elevation of a boiler showing
my invention as applied thereto and Fig. 2 is an elevation (partly in section) on
a larger scale, of the combined valve and tap which forms a principal part of
my invention.
On Sheet 2 of the drawings Fig. 3 illustrates a modification of my invention.
a is a portion of the end of a boiler and 6 one of the furnace doors in the casing
of which is provided a curved series of radiating slots or grids covered and un-
covered by a sliding plate c.
For the purposes of my invention I attach to the hinge of the furnace door 6
a vertical spindle d the other end of which has attached to it, the spindle of a
conical plug tap or the screwed spindle of a tap e which is provided with an
admission opening f communicating with the ordinary town pipes or other con-
venient source for the supply of water under pressure, and with an exit opening
at gas seen at Fig. 2.
The tape is thus opened and closed by the opening and closing of the door
of the furnace to the hinge spindle d of which it is attached as previously men-
tioned.
When the tape is opened by the opening of the furnace door b the water under
pressure is admitted by the opening g into the lower end of a vertical cylinder h
in which works a piston which is preferably provided with a cup leather, but
it may be otherwise suitably packed.
To this piston is attached a plunger or rod k passing out through the top of the
cylinder hand as the piston is raised by the water the upper end of the said

page_text: rod acts (by means of a lever and link m) upon a bell-cranked lever n the
horizontal arm of which is weighted.
The hanging arm of this lever n terminates in a segmental jaw n³ which em-
braces a stud or projection o attached to the slide c which closes or opens the slots
or grid in the furnace door. b.
The operation of the apparatus is as follows; -
The opening of the furnace door b turns (by means of the rod d) the plug or
screwed spindle of the tape and admits water beneath the piston i which is forced
upwards in the cylinder hand in rising uncovers the small exit orifice ? (see
Fig. 2), thus allowing the water slowly to escape from the cylinder h, and at the
same time lifts the weighted arm of the lever n the forked arm of which n* comes
against the stud or projection o and opens the grid round the door 6 by means of
the curved plate c and admits air to the furnace.
The width of the fork or jaw n* at the lower end of the arm is such that the
falling of the weighted arm n after the door 6 has been closed has no immediate
effect on the slide c until a certain quantity of the water (say about two thirds)
has escaped through the small orifice p and by this time the other side of the
fork or jaw n comes against the projection or stud o on the slide c and commences
to close the same so as gradually to shut off the admission of air through the grid
or grids and to close the same entirely by the time that all the water has escaped.
By adjusting the width of the jaw or fork n by a set screw or otherwise
the apparatus can be caused to shut off the air supply automatically at any
given or desirable time after the closing of the furnace doors, and this may be also
further regulated by providing the exit opening p with an adjustable stop tap.
As a modification (see Fig. 3 Sheet 2) I propose to dispense with the bell
crank lever by prolonging and weighting the level 7, and prolonging the link m
and providing the same at its lower end with a slot m³ which acts in the same
way as the fork * in the previously described arrangement, upon the stud or
projection o on the slotted slide c. By making the length of this slot adjustable
by a set screw or otherwise the time of automatically shutting off the air after
closing the furnace door can be regulated as may be desired.
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:-
The improved apparatus for closing the air grids above the furnace door at
any given time after closing the latter, by the action of water or other fluid under
pressure substantially as hereinbefore described and illustrated by the drawings
annexed.