Propelling, or Circulating Air or Gases.
Year: 1886

page_text: Propelling, or Circulating Air or Gases.
I, JAMES HOWORTH of the Victoria Works, Farnworth in the County of
Lancaster, Ventilating 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 ventilators for exhausting or propelling hot or cold air,
vapour, dust, smoke or gases, also for agitating or circulating the air within a
room in place of punkahs, and consists in an improved construction or arrangement
of the fans or propellers of such ventilators and the use of chambers and valves for
equalizing the pressure and flow of the air and for preventing back draughts.
And in order that my Invention and the manner in which it is carried into
practical effect may be more readily ascertained and understood, I have hereunto
appended a sheet of drawings marked with letters of reference, similar letters.
denoting similar parts in the different figures.
Figure 1 is a longitudinal section of the apparatus with the fan or propeller
hereinafter described, indicated only in outline.
Figure 2 is an end view of the apparatus as seen from the side on which the
air enters.
Figure 3 is a side view and figure 5 an end view of the fan or propeller.
Figure 4 is a perspective view of the boss and wings hereinafter described to
which the blades of the fan or propeller are fastened.
Figure 6 shows a modification of the front part of the ventilator.
The apparatus consists of a cylinder or casing a of iron or other metal, stiffened
at each end by metal rings a¹ a, in which two three armed bosses c and c¹ are
fixed. These bosses are bored centrally with the cylinder or casing a. A shaft d
can revolve in the bosses c and c¹ and be rotated by a pulley fixed on the outer
end of the shaft and driven by a band, strap, chain or other ordinary means from-
a steam engine or other motor, or the shaft may be turned by a crank by hand
or treadle when the apparatus is used instead of a punkah for circulating and
Price R71

page_text: agitating the air in a room. A boss k is fixed upon the shaft and has a number of
inclined lips or wings n n cast on it to which the blades ff are secured by bolts or
set screws. The blades are bent or curved in a spiral form and inclined to the axis
of the shaft, the front edges f1 f¹ being the leading edges in the direction of the
rotation. The blades before being bent are also cut on their edges to form arcs
of a circle having their centres on or near the centre line of the shaft and the
outer ends are cut off radially or approximately radially, and are wider than the
inner ends. An annular disk or flat ring e is fixed inside the cylinder or casing a
which confines the influx of the air to a smaller area than that of the cylinder
or casing.
.
Figure 6 shows a modification of the arrangement shewn by figure 1. The arms
of the boss are bent outwards and the ring is placed just inside the cylinder or
casing with notches cut out for the arms to pass through, as shown on figure 6.
By this modified arrangement the fan or propeller can be brought nearer to the
front edge of the cylinder or casing and the depth of the latter correspondingly
reduced, so that it can be placed into thin walls or window frames without
projecting to the outside. The air impinged upon by the rotating blades is
propelled in a radial direction by the centrifugal force produced and at the same
time in an axial direction by the inclination of the blades to the axis and passes
along the blades under the combined action of the two influences and is delivered.
on the opposite side from the back and outer edges of the blades into a chamber g.
In consequence of the curvature of the blades the air passes freely through the
fan or propeller with less resistance than in screw or similar ventilators and my
improved ventilator requires less power for driving and exhausts a greater quantity
of air than such other ventilators of the same size. The inlet area being less than
the area of the fan cylinder causes the flow of air to be accelerated through the
opening of the ring e and a more rapid current and exhaust to be produced
whereby the dust and similar impurities contained in the air are, more effectually
removed from the room to which the ventilator is applied.
As the blades are fastened to the lips or wings n n cast solid with the boss k
the correct position of the blades is unalterably secured by this means and when
a blade is damaged, it can easily be removed and replaced without much loss of
time or expense. The outer ends of the blades are stayed and connected to each
other by rods m m which may be attached to the blades in any ordinary manner.
The chamber g into which the air is discharged by the fan 'or propeller is made
square at its outer or delivery end, which is provided with flap valves lll hinged
at the ends on light pivots and balanced by the rods 11, so that the slightest
air pressure from the inside will open them, while they will close if there is a
stronger wind pressure against them from without than the internal pressure
produced by the propeller or fan. The chamber g serves to equalize the pressure
and produces a more uniform delivery of the air. Where the ventilator is used for
circulating and agitating the air in place of punkahs, the chamber and valves may
be omitted.
Brackets or feet bb are cast on the rings or otherwise attached to the rings or
cylinder, by means of which the apparatus is fixed upon a wall bracket or attached
to the ceiling of the room or secured in any desired horizontal, vertical or inclined
position according to the purpose for which it is to be used, or it may be fixed upon
a movable stand or table, so that it can be moved from place to place for the
purpose of producing currents of air where most required in a room and be used
instead of punkahs.
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.) In ventilators for exhausting, propelling or circulating air or gases the
construction of the fan or propeller with blades bent spirally and curved on their

page_text: edges and placed at an incline to the axis of rotation substantially as hereinbefore
described and illustrated by the drawings.
(2.) The use of a boss with wings or lips n n cast on it for attaching the blades
of the fans or propellers of exhausting or air circulating ventilators.
(3.) In combination with fans or propellers as specified under claim 1, the use of
a chamber g with outlet valves substantially as illustrated by the drawings
and as and for the purpose herein before described.
(4.) The use of a movable stand or table for carrying air circulating ventilators.