IMPROVEMENTS IN ROTARY BLOWING AND EXHAUST FANS WHICH IMPROVE- MENTS ARE ALSO APPLICABLE, ALSO TO MANY OTHER USEFUL PURPOSES."
Year: 1883

page_text: LETTERS PATENT to Henry Aland of Cavendish House Harbut Road New
Wandsworth in the County of Surrey Engineer. for an Invention of
IMPROVEMENTS IN ROTARY BLOWING AND EXHAUST FANS WHICH IMPROVE-
MENTS ARE ALSO APPLICABLE, ALSO TO MANY OTHER USEFUL PURPOSES."
COMPLETE SPECIFICATION filed by the said Henry Aland at the Office of
the Commissioners of Patents on the 20th June 1883.
HENRY ALAND of Cavendish House Harbut Road New Wandsworth in the
County of Surrey Engineer IMPROVEMENTS IN ROTARY BLOWING AND EXHAUST
FANS WHICH IMPROVEMENTS ARE ALSO APPLICABLE, ALSO TO MANY OTHER
PURPOSES
i
My invention relates to improvements in Rotary Fans for Exhausting and
Blowing purposes for the ventilation of Mines, Tunnels, Factories, Schools
Agricultural, and other purposes, where a great suction and discharge is required
and which improvements may also be applied to Fans hitherto in use so as to
increase the volume and pressure of the discharge and power of the suction and
thereby increase the efficiency of the known laws which govern the limits of the
powers of Rotary Fans
Such Fans or Blowers may be driven by steam, Hand, or any other Motive
power, most convenient of application
Now my Invention consists of increasing the suction of the inlets of Rotary
Fans to the size, or nearly the size, of the diameter of the revolving disc, and in
which revolving disc, I form inlets from the partially exhausted case either on ono
or both sides of the said revolving disc, in addition to the central inlet or inlets as
in ordinary fans hitherto in use, so that as soon as the said revolving disc, or pro-
pellor is set in motion a small partial vaccumn is created in the case and, I so form
the revolving propellor or disc to recive the smaller partial vaccumn in the case
into a much greater vaccumn in the disc or propellor when the Air or Vapours
submit to the Laws of compressed fluids which is equal in all surfaces in compression
or partial Vaccumn
"

page_text: In order to illustrate this invention and that it may be better understood I
bereby annex three sheets of Drawings
Sheet 1 Figure 1 is a diagram to illustrate the Action of the air in the Revolving
disc in producing a partial vacuum in itself as before referred to. The Arrow 1
indicates the direction in which the disc revolves and it will be clearly seen that i
the blade or propellor of the fan revolving at a much greater speed than the Air or
vapour which it is required to throw out by its centrifugal Action, must cause the
Air or Vapour or fluid which is at the back of the blades to impinge on the Air,
Vapour or fluid in front of the said blades or vanes of the disc, and which by the
centrifugal force is forced to the discharge in the periphery of the revolving disc
into the open Atmosphere and by this-Action-produces a partial vacuum at the
back of the blades, and a corresponding compression towards the front of the blades-
as indicated by the light part shewing the vacuum and the dark portions the
increasing compression
Now to prevent this vacuum and thereby increase the power of the Fan I form
openings in the sides of the revolving Fan immediately behind the blades or
propellors as shewn in sheet 2. Figures 1 and 2. which are sections of an Exhaust
Fan, and which I will now proceed to describe. The letters in both figures refer
to the same parts AAAA is the case of the Fan and may be constructed of Iron,
Wood, or any other suitable material and which I construct of a size approximately
equal to the diameter of the periphery of the revolving disc and with which
periphery I form a close joint shewn at Figure 3 sheet 2 and which figure shows
two methods of making this closed joint, the one with an elastic Material such as
Indiarubber A' Figure 3 Sheet 2., and the other with a Metalic material
such as a ring of iron, brass or other metal A³ Figure 3 Sheet 2. It will
thus been seen that I am enabled to increase my suction and inlets for the
Air cr Vapour to the maximum, through the inlets G. G. G. G. G. G. as before
referred to, and I form my openings immediately behind the blades, where
the vacuum is produced and thereby enabling the greater vacuum behind the
blades to draw from the lesser vacuum in the case A A A A as before referred to.
B. B. Sheet 2 Figures 1 and 2 is the fan disc, or revolving propellor which is keyed
on to the Shaft C. C. and which revolves in the Bearings D. D. the blades E. E.
E. E. E. E. are formed involute, but I use different forms of blades, as I may find
most suitable to the circumstances and requirements of the work it is to be applied
to. I also fix a cover to the back of the periphery of my blades shewn at F F F F
FF to prevent the discharged Air, or Vapour coming in contact with what would
be a partial vacuum, but for the enormous suction passages behind the blades
shewn at G. GG GG G. thereby filling up a great vacuum created in other fans,
and greatly increasing the discharging power. HH, are the suction inlets which
inlets may be formed or fixed to any part of the case round its periphery or
latterally it is shewn in the drawings at the bottom of the case which lead to the
vessel or vessels, chamber or chambers to be exhausted the Darts shew the direction
of the Air, or Vapours, from the Chamber or Chambers to the Fan case A A A A
and from thence into the Revolving disc through the central openings K K, and
passages G G G G G G, from which it is discharged into the open Atmosphere, or
suitable pipes or passages, if required to be utilised or conducted in any special
direction. L is the Driving pulley
Sheet 3 Figures 1 and 2 show my Rotary disc, with curved and Tangential
blades, or propellors and fitted with the exhaust passages at the back of the
blades G G G G G G. as before discribed from the foregoing explanation it will be
seen that this invention can be applied to all fans hitherto or hereafter in use
when such fan have any form of side plates to the blades and I particularly wish
it to be understood that I do not confine myself to any particular shape or con-
figuration of the blades or Propellors or to any particular shape or form of my
openings behind the blades or to any number of blades, or propellors in the
Rotary disc.

page_text: Having fully described my Invention and the manner in which the same is to be
performed what I claim and desire to secure by Letters.Patent is
1 Increasing the diametor and area of the suction in the Fan case from the
central inlets to the diametor of the Revolving disc as before described
2nd The forming of an approximating Airtight joint at the periphery of the
revolving disc or propeller with Indiarubber or metal or other suitable means for
the purpose herein described
3rd: The inlet openings at the side of the Back of the blades or propellors of the
Revolving disc to receive into its greater partial vacuum in the disc from the
smaller vacuum created in the fan case
4th The covering at the periphery of the blades to divide the discharged Air
from the suction behind the blades when required
In witness whereof, I, the said Henry Aland
have hereunto set my hand and Seal, this
nineteenth day of June in the Year of Our
Lord One thousand eight hundred and eighty
three
HENRY ALAND (L.S.)