Improvements in Forced Draught or Blast Fans.
Year: 1890

page_text: Date of Application, 7th Jan., 1850
Complete Specification Left, 16th Sept., 1893-Accepted, 1st Nov., 1890
PROVISIONAL SPECIFICATION.
Improvements in Forced Draught or Blast Fans.
I, RICHARD ROWE, of 55 Nine Elms Lane, Battersea, in the County of Surrey
Engineer do hereby declare the nature of this invention to be as follows:-
My invention relates to apparatus for producing a forced draught or blast, for
boiler or other furnaces and consists of a combination of devices whereby the
dynamic energy of a steam jet is utilized as a motive power, to produce the said
forced draught or blast.
To carry my invention into effect I take a jet of live steam from a boiler or other
convenient source, and introduce a nozzle of very small diameter into the case of a
small fan, so adjusted that the steam jet will strike the vanes tangentially so as to
produce the rotation of the motor fan.
As this motor fan may be of smaller size and beneficially of different form to that
of a good air forcing fan. I attach the vanes of the latter in an independent casing
to the shaft driven by the motor fan and thus obtain a forcible blast of air.
Where the fuel to be burnt is dry, I find that I can lead the exhaust from the motor
steam jet fan into the blast pipe of the air fan, and feed them both together into a
furnace without injuriously affecting the fire by the dampness of the steam exhaust,
from which the condensed water is allowed to collect in a suitable pocket and is
drained off.
If the fuel should itself be damp, and the entrance of the exhaust steam be
undesirable, I fit a two-way valve into the junction of the exhaust pipes of the motor
and air fans so that I can shut off the steam exhaust from the air blast, and allow it to
escape separately so as not to pass through the furnace.
To increase the volume of air forced in by the air or by both fans, I find it useful
to surround the tapering blast pipe, with another external taper nozzle, open at the
back to the atmosphere so that the main blast in the central jet may induce a further
volume of air through the said external induction pipe.
Dated this 7th day of January 1890.
FELL & WILDING,
1, Queen Victoria Street, E.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Forced Draught or Blast Fans,
I, RICHARD ROWE, of 55, Nine Elms Lane, Battersea, in the County of Surrey,
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 :-
My invention relates to apparatus for producing a forced draught blast or exhaust
for boiler or other furnaces, and consists of a combination of devices whereby the
dynamic energy of a steam jet is utilized as a motive power to mechanically rotate
the fan to produce the said forced draught, blast, or exhaust.
To carry my invention into effect I take a supply of live steam from a boiler or
other convenient source, and introduce a nozzle or nozzles of very small diameter into
the case of a small fan, so adjusted that the steam jet will strike the vanes tangentially,
so as to produce the rotation of the fan.
The steam jet or jets may impinge on the extremities of the vanes of an air forcing
fan; or as the motor fan may be of smaller size and, beneficially, of different form to

page_text: that of a good air forcing fau, I may attach the vanes of the motor fan in an
independent casing to the shaft, driving the blast fan, and thus obtain a forcible blast
of air; or, equivalently, I may add auxiliary vanes to the periphery of the air fan, and
these auxiliary steam vanes may travel in a distinct compartment divided from the
air fan.
Where the fuel to be burnt is dry, I find that I can lead the exhaust from the
motor steam-jet fan into the blast pipe of the air fan, and feed them both together
into a furnace, without injuriously affecting the fire by the dampness of the steam
exhaust, from which the condensed water is allowed to collect in a suitable pocket and
is drained off.
If the fuel should itself be damp, and the entrance of the exhaust steam be
undesirable, I fit a two-way valve into the junction of the exhaust pipes of the motor
and air fans, so that I can shut off the steam exhaust from the air blast and allow it
to escape separately so as not to pass through the furnace. To increase the volume of
air forced in by the air fan or by both fans, I find it useful to surround the tapering
blast pipe with another external taper nozzle, open at the back to the atmosphere, so
that the main blast in the central jet may induce a further volume of air through the
said external induction pipe.
In order that my invention may be the better understood I now proceed to describe
the same in relation to the drawings hereunto annexed, reference being had to the
letters and figures marked thereon.
Figure 1 is a transverse section through one convenient form of my steam impact
blast fan.
Figure 2 is a longitudinal section of the same.
A is the air chamber of an ordinary air blast fan, in which the vanes a are caused
to revolve, inducting by centrifugal action an in-draught of air through the central
perforated bracket B, and ejecting the said blast through the tangential orifice b.
The vanes a are mounted on a disc or arms C which is provided with a boss D, keyed
to a spindle E, carried on suitable lubricated bearings in the brackets B B.
In order to cause the said air blast fan to revolve, a steam jet or jets may be admitted
anywhere through the outer casing, so as to cause the said steam jets to impinge upon
the faces of the air vanes a in such a manner as to cause the desired rotation. Or
equivalently a distinct motor fan in a separate compartment may be keyed to the said
spindle E to receive the impact of the steam jets, and placed alongside the aforesaid
air chamber.
But preferably, as shown in the drawings, I provide an independent steam chamber S
surrounding the periphery of the air chamber, and conveniently made in one part
with it, the casing being put together in two parts with the central flange joint as
shown. The central disc or arms C of the air fan extends through a suitable slot in
the casing into this external steam chamber S, so as to carry therein steam vaness s
against which the jet or jets of steam are caused to impact, thus producing the desired
revolution of the air fan.
The spindle of the fan may be kept in its true position within the case by collars or
by conical set screws with locking back nuts engaging into grooves on the said
spindle.
The exhaust steam, by the centrifugal action of the rotating fan upon it, will escape
by the external exhaust passage F, in which is situated the flap valve V, by which
one of the alternative passages T, and W may be opened and the other closed
respectively. When the valve closes the passage W, as shown in the drawing, the
exhaust passes by the nozzle G into the air blast exit pipe b, as I find that where the
fuel is dry I can use the mixed steam and air blast with advantage to the fire, and
with beneficial effects as regards the combustion of smoke. Should however this not be
desirable the valve V may be moved to the dotted position to close the nozzle exit G
and to open the direct exit W for the exhaust steam, which may be carried elsewhere
to effect the heating of a drying room or other convenient purpose.
It is obvious that this fan may be applied equivalently for exhausting as for forcing
the air blast.

page_text: 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 :-
1st. The combination upon a single spindle of an air forcing or exhaust fan, with
the vanes of the air fan, or an auxiliary motor fan, or accessory vanes, subjected to
the impact of a jet or jets of steam, to produce the rotary motion of the said air
fan substantially as described.
2nd. In such a combined steam impact air-fan, the combination (for economy) of the
steam exhaust with the main air blast substantially as and for the purposes described.
3rd. In such a combined steam impact air-fan, a two way valve, controlling
alternative exit orifices, by which the exhaust steam can be mixed with the air blast,
or diverted into another independent channel at pleasure, substantially as described.
Dated this 16th day of Sentomber 1900
FELL & WILDING,
1, Queen Victoria Street, London, E.C., Agents for the Applicant.