Improvements in Exhaust and Blast Fans.
Year: 1891

page_text: Date of Application, 21st May, 1891
Complete Specification Left, 22nd Feb., 1892-Accepted, 21st June, 1892
PROVISIONAL SPECIFICATION.
Improvements in Exhaust and Blast Fans.
I, GEORGE MARIE CAPELL, of Passenham Rectory, in the County of
Northampton, Clerk in Holy Orders, do hereby declare the nature of this invention
to be as follows :-
:-
My invention has for its object the improvement of centrifugal fans for exhausting
large volumes of air and also for fans for forcing or blowing air.
The fan consists of two parts in combination a centrifugal fan, and a collector.
The fan may consist of two side discs or plates each having a boss secured to it
to carry a shaft or axle. To these discs I secure the blades or wings which are
set at a suitable angle and dip down towards the centre. These blades or wings
are either curved or straight and either parallel to or diagonal to the axis. In
some cases I employ a drum or cylinder having openings set diagonally to the axis
and fasten the blades to one side only of the openings or port holes on the same
angle to the axis as the openings and secure them to one side disc only.
In each case I have one side disc with openings wider towards the periphery
than the portion nearer the centre. They may be any suitable number to suit
varying circumstances. In depth they will be about of the radius of the disc.
Over each opening I place a scoop having one side secured to the disc. The side
nearest the periphery is bent on the segment of a circle larger than the circle on
which the portion of the scoop over the part of the opening nearest the centre is
bent.
The end of the scoop comes below the opening in the disc and at this point is
secured to it
Round the scoops on their periphery and embracing them all I place a metal
band secured to the disc and, to this band the outer ends of the scoops are all
secured.
In mine ventilators, I may use an expanding spiral casing, with an évasée outlet
expanding in hopper-form. But in some cases I dispense with a casing wholly or
partially.
In blowing fans I use an expanding spiral casing with inlet and outlet.
In large volume fans I may build up two complete fans on one central driving
disc, with scoop-discs on each side. The scoops collect the air pass it through the
openings in the disc, to be acted on centrifugally by the blades of the fan set
between the discs.
Dated this 1st day of May 1891
Round the scoops on their periphery and embracing them all I place a metal
band secured to the disc and, to this band the outer ends of the scoops are all
secured.
In mine ventilators, I may use an expanding spiral casing, with an évasée outlet
expanding in hopper-form. But in some cases I dispense with a casing wholly or
partially.
In blowing fans I use an expanding spiral casing with inlet and outlet.
In large volume fans I may build up two complete fans on one central driving
disc, with scoop-discs on each side. The scoops collect the air pass it through the
openings in the disc, to be acted on centrifugally by the blades of the fan set
between the discs.
Dated this 1st day of May 1891
PHILLIPS & LEIGH,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Exhaust and Blast Fans.
I, GEORGE Marie Capell, of Passenham Rectory, Stony Stratford, in the
County of Northampton, Clerk in Holy Orders, 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 improvements in exhaust and blast fans, and its object
is to improve those which have to deal with large volumes of air irrespective of
whether the air is to be exhausted, as from a mine, or to be blown, as into a
furnace.

page_text: A fan constructed according to the present invention consists of two parts in
combination, a centrifugal fan and a collector.
The fan consists of two side discs; central bosses secured thereto to provide for
keying the fan to the shaft on one side and for holding the arms to the shaft on the
other and blades. The latter may be either curved or straight. They may also
be parallel with, or at an angle with, the axis of the fan. In some fans I employ
a drum or cylinder having fan ports diagonal to or parallel with the axis, fastening
the blades to only one side of the air ports at the same angle to the axis as the air
ports, and to only one side disc.
In each case a circular series of air-ports is formed in that side disc through
which the air is sucked into the fan. These air ports are hereinafter referred to
as disc ports. They are close to the periphery, and are generally radial on one
side to the axis, but the direction of the other may be varied according to the
position of the scoop hereinafter described. Consequently, these disc ports are
wider towards the periphery than towards the centre of the disc. I do not confine
myself in respect of their number which is varied to meet the requirements of
each particular case. The depth of a disc port, i.e. the length measured radially,
is about two thirds of the radius of the disc, or of the radius of the inlet which it
is proposed to make to the fan. A scoop of a special shape is fixed to the outer
face of the disc over each disc port. The side nearest the periphery is bent on the
segment of a circle larger than that on which the portion of the scoop over the
part of the disc port nearest the centre is bent. The end of a scoop, ie, the point
nearest the said centre, is continued beyond the disc port and is secured to the
disc.
A peripheral band is led round the circle of scoops so as to embrace them all
and close their backs, i.e., the ends towards the periphery of the disc. The band
is secured to the disc.
The above described combination of scoops and band co-operating with the disc
ports constitutes the collector.
The function of this collector is to pass air into the centrifugal portion of the
fan. It is to be noted that the inlet area of the centrifugal portion of the fan is
provided by the disc-ports, and that the central portion of the disc is closed. This
closure is a great advantage and a feature of the present invention. The scoops
collect the air centrifugally in front of the said closed central portion and throw it
outwards in the direction of the disc ports.
In mine ventilators I may use an expanding spiral casing with an evasée outlet
expanding in hopper form. But in some cases I dispense with a casing, either
wholly or partially.
In blowing fans, I use an expanding spiral casing with inlet and outlet.
In large volume fans I may build up two complete fans on one central driving
disc, each fan being provided with a collector on its inlet sides.
In order that my invention and the best means of carrying it into effect may be
thoroughly understood, I will now describe it and them in detail, referring in so
doing to the accompanying drawings which are to be taken as part of this Speci-
fication.
Fig. 1 is a side elevation of a mine fan. The case is shewn in section.
Fig. 2 is a sectional front elevation taken on the line Y-Z of Fig. 1:
Fig. 3 is a side elevation shewing disc ports, blades, and opposite disc.
Fig. 4 is a side elevation of a modification according to which the fan is of a
larger diameter than the collector.
Fig. 5 is a front elevation corresponding therewith.
Fig. 6 is a half side and half sectional side elevation of a fan, the blades and fan
ports of which are both at an angle with the axis of the fan.
Fig. 7 is a front elevation corresponding therewith.
Figs. 8 and 9 are respectively elevation and inverted plan of a scoop.
Fig. 10 is an end view of a modified form of scoop looking at it from the
centre.

page_text: Referring to Figs. 1, 2 and 3, a, a¹ are the two side discs, b, b¹ are the bosses
bolted thereto, is the shaft, and d, d are the blades. The latter are shown as
curved and parallel with the axis, but, as already explained, they may be straight
and the parallelism may be replaced by a, respectively, angular position. They are
shewn as connected to both discs by angle irons d' dare stays from blade to
blade. e is the cylinder. are the fan ports. They are always parallel with
the blades. g are the disc ports in the disc a'. The parts described above
constitute the fan. k, h are the scoops. They are rivetted or otherwise secured
to the disc a¹, one over each disc port g. Of each scoop, h' is the leading edge,
is the back, and is the flange formed out of the scoop and along which
the latter is rivetted to the disc. is the end of the scoop. This end, it will
be noticed, is continued beyond the disc port. In curving a scoop, I make the
peripheral portion joining the band on the radius of a larger circle than the
portion near the centre of the disc. In some cases I make the last mentioned
portion as follows. It starts from the disc at a right angle therewith and is
continued so for a short distance before the curvature commences. This feature
is shown in Fig. 10. i is the band. It is naturally of a sufficient diameter to
fill the air drift and in so far resembles the prolongation of a battle ring described
and illustrated in the Specification of a former Patent No. 1282º¹. This band
encircles the scoops closing up their backs as already explained.
jis the air drift. is the expanding spiral fan case; and 7, the evasée outlet.
Referring to Figs. 4 and 5, the discs a, al are both of them of larger diameter
than the collector. The form of blade which I prefer to use in the fan now under
specification is one curved in two portions, one dipping into the centre from the
inlet-circle of the disc, and struck on the radius of the inlet circle or nearly so;
and the other of them curved at an angle from 70° to 85°, meeting the inlet
circle at that angle and extending outwards to the periphery of the disc. The
blades are secured to both side discs by suitable means. In other respects, the
construction of the fan is the same as that described with reference to Figs. 1, 2
and 3. The same modifications as to shape and position of blades and ports are
also applicable.
Referring to Figs. 6 and 7, the modification illustrated consists in setting the fan
ports and blades at an angle with the shaft. In other respects the construction of
the fan and collector is the same as illustrated in Figs. 1, 2 and 3, and described
therewith.
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:
1. In centrifugal fans, the combination of disc, disc ports therein, and collector
adapted to pass air through the said ports.
2. In centrifugal fans the combination of a side disc closed as to its centre and
having disc ports formed in it, and scoops, one over each port, and extending past
them in the direction of the centre of the disc.
3. The combination of scoops and peripheral band constituting the collector with
disc ports.
4. The combination of a centrifugal fan with a collector of a smaller diameter
as described with reference to Figs. 4 and 5.
5. In centrifugal fans, the combination of a collector and cylinder as illustrated
in Figs. 6 and 7 and described therewith.
Dated this 22nd day of February 1892.
PHILLIPS & LEIGH,
22, Southampton Buildings, Chancery Lane, W.C.,
Agents for the Applicant.