Improved Means for Controlling the Draft to Furnaces.
Year: 1897

page_text: Improved Means for Controlling the Draft to Furnaces.
I, EDWARD WILSON, of Commercial Road, Exeter, in the County of Devon,
Engineer, do hereby declare the nature of this invention to be as follows:-
The present invention relates to improved means for controlling the draft to any
kind of furnace and it consists in the employment of one or more hollow bars which
may either be substituted for the ordinary fire-bars or may be used in combination
with such bars, and (when two or more sections of fire-bars are employed) may be
applied to all or any one of such sections.
The improved bar or bars may be employed either for producing a forced draft
by means of a steam jet through the bar, or a natural draft only by means of an open
communication with the ash pit or outer atmosphere, in which case they may be
employed with a closed ash pit and an independent steam jet or blower.
The main objects of the invention are:-Firstly, to regulate the space through
which the air passes into the fire so that the force of such air may be controlled
to the best advantage, or in other words to vary the volume of air entering while
increasing or diminishing its intensity; Secondly, to so direct the draft that same
will pass preferably in a horizontal direction through the fire instead of vertically
up through same; Thirdly, to provide means for keeping the air orifices clear from
dust and clinker; and, Fourthly, to provide a space for the reception of slag or
dust below the air orifices.
In carrying out my invention I employ hollow bars with slots or orifices com-
municating with the interior space of such bars and passing out in an approximately
horizontal direction at or near the upper part of such bars, and above the floor of
the clinker or dust space.
These slots or orifices may be cast or otherwise formed directly through the upper
part of the walls of the bars, but I prefer to make a single longitudinal slot at the
upper part of such bars and to fit therein a longitudinal bar of either T or Y sec-
tion, provided at suitable intervals with webs to keep it in the centre of the longi-
tudinal slot. I further employ means for enabling the T or Y bar to be raised
or lowered so as to control the space left between its head and the edge of the
longitudinal slot in the bar. For this purpose suitable cams mounted on a spindle
or cast in one piece and actuated from the outside of the furnace may be arranged
so as to act upon the underside of the T or Y bar and raise and lower it at will.
The movable bars are loose so that they can be taken out and renewed.
In order to permit of the removal of any ashes which may pass through the air
orifices of the bars from the interior space thereof, a hole covered by a movable
plate may be provided in the bottom of each bar.
When the blower bars are employed in place of ordinary furnace bars they can
be set so as to leave spaces between the adjacent bars through which the ashes

page_text: can pass to the pit or receptacle beneath, or the space may be blocked up and form
the space for clinker &c.
The bars themselves are also preferably provided with means for rocking same so
as to keep the air spaces clear from dust or clinker.
When the bars are employed for producing a forced draft in the furnace a tube
communicating with the interior of such bars projects out to the front of the
furnace, and in front of same a steam jet is arranged. This.tube may be suspended
by clamps or other suitable means from the dead-plate at the front of the furnace,
or supported on the sides of boiler tubes or brickwork, and same may be mounted
so as it is capable of revolving and be connected to the spindle carrying the canis
by which the height of the T or Y bar is regulated.
When the furnace is required for either ordinary draft, or with an independent
blower, bars of a channel form with the movable bars between them may be used.
The blower bars may if desired be arranged in a boiler tube without any ash pit
beneath, in which case they would not be made to rock, but I prefer however the
arrangement previously described.
Doted thin th
1 1007
ALLISON BROS.,
Agents for the Applicant.
Improved Means for Controlling the Draft to Furnaces.
I, EDWARD WILSON, of Commercial Road, Exeter, in the County of Devon,
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 present invention relates to improved means for controlling the draft to any
kind of furnace, and it consists in the employment of one or more bars of special
construction which may either be substituted for the ordinary fire-bars or may
in some cases be used in combination with such bars, and when two or more sections
of fire-bars are employed may be applied to all or any one of such sections.
The improved bars may be employed for producing a forced draft through same
by means of a steam jet, in which case a closed ash pit and an independent steam
jet or blower are preferably used.
The main objects of the invention are:-Firstly, to regulate the space through
which the air passes into the fire so that the force of such air may be controlled
to the best advantage, or in other words to vary the volume of air entering while
increasing or diminishing its intensity; Secondly, to so direct the draft that same
will pass preferably in a horizontal direction through the fire instead of vertically
up through same; Thirdly, to provide means for keeping the air orifices clear from
dust and clinker; and, Fourthly, to provide a space for the reception of slag or
dust below the air orifices.
My invention is illustrated in the accompanying drawings in which ;-
Fig. 1 is a transverse section of part of a furnace provided with bars constructed
and arranged in accordance with my invention, and
Fig. 2 a longitudinal section of same.
Fig. 3 is a similar view to Fig. 1 showing a modified form of the bars, and
Fig. 4 a longitudinal section of same.
In carrying out this invention according to the arrangement shown in Figs. 1
and 2, I employ bars A having central slots B, such slots being provided with

page_text: flanges C on each side. The bars A are so arranged in the furnace that the slots
are in communication with the blast supply D, and so that the blast can pass
through same into the fuel which is arranged on the bars and over and around the
flanges C. To carry out one of the main objects of my invention I arrange in each
of the slots B a Tor Y-shaped bar E, which is so formed and situated that its
upper part will entirely cover the top of the slot B, but leaving a space & at each
side, thereby causing the blast to issue from the slot through the space c, and
consequently in a horizontal or substantially horizontal direction.
The Tor bars E are preferably provided at suitable intervals with webs or
flanges e, which keep them in the centre of the slots B in the bars A. I further
employ means for enabling the T or Y bars E to be raised or lowered so as to
control the space c left between the lower surface of the heads of same and the top
of the flanges C, and thereby the amount or force of air admitted to the fuel. For
this purpose cams F mounted on a spindle G (or cast in one piece therewith) and
actuated from the outside of the furnace may be arranged so as to act on the lower
edges of the T or Y bars and raise or lower same at will. In the drawings I have
shown the spindle G carrying the cams F as being actuated by means of an arm I
mounted on the spindle, a rod J connecting such arm I with a lever K pivotted
outside the furnace, so that on such lever K being operated in one or the other
direction the T or Y bars E will be raised or lowered as desired.
The bars E are arranged loosely in the slots B so that they can be taken out and
renewed if necessary.
It will be readily understood that instead of the bars A being of the form above
described, they may be of channel section, having flanges B at each side, and in this
case they will be arranged at suitable distances apart, and the T or Y-shaped bars E
will be placed between them in the spaces so formed.
In the modification of my invention shown in Figs. 3 and 4 the T or Y bars E
are made hollow, the object of this being to enable steam to be injected through
same so as to keep them cool and prevent them becoming distorted or the whole
structure collapsing from excessive heat, which might take place when the ordinary
blast is shut off. With this object the space L in the interior of the bars E is in
this arrangement placed in constant communication with a small jet of steam M
while the furnace is in operation, this having the effect of creating a draft inside the
bars E, which will keep them cool and prevent any distortion or damage to the
apparatus.
The upper surfaces of the adjacent bars A on each side of the flanges C and
below the air orifices c may form the space for clinker, &c. The upper edges of
the flanges C are also preferably bevelled off as shown, this, assisted by the action
of the blast itself, tending to keep the air orifices a clear and free from dust and
clinker.
It will be understood that instead of either of the arrangements above described
tubular bars may be employed, the upper part of each of which is provided with a
central longitudinal slot in which a T or Y har is arranged as described, the upper
arms of which are so situated in relation to the slot that the blast will issue from
the opening left between the edges in a horizontal or approximately horizontal direc-
tion. If this arrangement is employed the interior of the tubular bars will be
placed in communication with the blast (any suitable apparatus for producing which
may be employed).
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:
1. A furnace bar provided with orifices opening outwards in substantially a hori-
zontal direction, the areas of such orifices being controlled by an adjustable bar
so as to direct the draft through the fuel horizontally instead of vertically, sub-
stantially as described.
2. Making the adjustable bar for controlling the areas of the orifices in the

page_text: furnace bars hollow, and injecting steam through same at all times when the
furnace is in operation, substantially as and for the purposes described.
TL 9 1 of Tonuary 1900
ALLISON BROS.,
Agents for the Applicant.