Improvements in Centrifugal Fans, Pumps, and Propulsive Turbines.
Year: 1893

page_text: Date of Application, 23rd Oct., 1893
Complete Specification Left, 23rd July, 1894-Accepted, 15th Sept., 1894
PROVISIONAL SPECIFICATION.
Improvements in Centrifugal Fans, Pumps, and Propulsive
Turbines.
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 :-
In my Patent No. 12821891 I have described my improvements in fans having
inner and outer wings according to my Patents 31301882 and 31171883.
I have since carried out experiments and have further increased the power of
these fans. The improvements I have now to describe relate principally to a new
form of inner wings, which are suitable also for the single winged scoop fans
described in my Patent No. 87071891.
I use outer wings coming down to the periphery of the inlet circle. These
wings are parallel to the axis of the fan, and are set at an angle of from 65 to 82°.
Joined to these by a triangular shaped junction piece (unless formed in one piece
as in small fans) are the inner wings which I prefer to set at an angle to the axis,
so that the ends on the inlet side in the direction of rotation are in advance of the
edges on the opposite side to the iulet but in some cases I may use inner wings set
parallel to the axis.
The fan has two side discs, one with an opening to form an inlet. Round the inlet I
fix a deep metal baffle ring of metal. The inner wings project into this ring, and
are so formed that before being bent into the scoop form I will describe, the lower
edge near the centre well projects beyond the ring, while the upper edges will be
inside the ring and nearer to the disc on the inlet side. This projection is curved
into scoop form so that the curve gradually increases from the point near the centre
to the periphery of the inlet circle. The scoops thus gradually leading the air
gathered in the fans rotation from the centre of the inlet to the openings between
the outer wings.
The inner wings may be curved or straight. The best position for the inner
wings is not radial, but in such a position, that a line drawn through the point
where they join the periphery of the inlet circle to the lower ends towards the
centre would pass in advance of the centre line in the direction of the fans
rotation. Where great strength is required I may use a cylinder construction to
fix the inner and outer wings, retaining the relative position of the inner and outer
wings and the special form of scoop ends to the inner wings now described. The
fans have arms in the inlet and the usual bosses.
I
may use a spiral casing with expanding outlet in large fans when high gauges
are not required. I may use the inner wings and scoops only secured to a disc
with a boss. on one side, and with another disc with an opening nearly the diameter
of the fan to form an inlet in this case. 1 curve the outer ends of the wings so as
to follow the curve of the fans periphery, and thus regulate the arm of the
discharge at the periphery. This fan has the deep inlet ring and the scoop ends
now described to the wings. In some cases I prolong the inner wings so as to
project into the chambers formed by the outer wings, and when using a cylinder
with openings narrower than the fan I may place pieces of metal between the
edges of the cylinder and the side discs rising to the height of the projection of
the inner wings into the cylinder so as to form an expanding outlet for the air to
enter the outer wing chambers, or I may contract the side discs from the periphery
to the width of the openings between the inner and outer wings to effect the same
end. In some special cases I may prolong the inner wings as described, and keep

page_text: them the same width as the openings and parallel sided when blast pressure is
required. The form of scoop end here described is applicable to centrifugal pumps
and propulsive turbines.
Dated the 92nd dow of Ontahan 1803
COMPLETE SPECIFICATION.
Improvements in Centrifugal Fans, Pumps, and Propulsive
Turbines.
I, GEORGE MARIE CAPELL, of Passenham Rectory, 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 centrifugal fans, pumps and propulsive
turbines. Throughout this Specification and the subsequent claims, the said fans,
pumps and turbines are, to prevent iteration, referred to as "fans."
The invention is applicable to any of either the single or the double types
illustrated in the blue books of either of the following Patents granted to me :-
No. 3130188, No. 31171883, No. 12821891 and No. 87071891. It should be here
explained that by single type, I mean one series of blades set about a central axle,
and by double type, two series of blades set about a central axle, one series inside
the other i.e., held between it and the central axle.
The first part of the present invention consists of the combination with the
blades of a single fan, or with the inner blades of a double fan, of a series of scoops
of novel and distinctive form. One of these improved scoops is fixed upon each
blade, the whole series of scoops projecting laterally from the fan beyond the inlet
opening of it.
Referring to my Patents Nos. 12821891 and 87071891, it will be seen that the former
describes lateral prolongations of the inner blades from the fan, and that the latter
describes the combination of scoops with a single fan as well as with the inner blades
of a double fan. The present invention differs from either the preceding inventions
in respect of the form of the scoop. It is not, as in the said former Patent, merely a
prolongation of the blade: it is a scoop attached to the blade; and its difference
from the scoop of the said latter Patent consists principally in this, that whereas
in the scoop of Patent No. 87071801, the arc of it next to the periphery has a longer
radius than that next to the axle, the lines of the scoop of the present invention are
reversed in respect of their position relatively to each other as well as to the said
periphery and axle, the are of shortest radius being now next to the periphery
while that of longest radius is next to the axle. A further novelty relates to the
position of the scoops upon the side of the fan, and according to this part of the
invention, they are not radial to the axle, but instead of being so, their rear edges
make an acute angle with a radius of the fan intersecting the periphery (or the
inlet circle, as the case may be) thereof at the point of junction of the said rear
edges with the said periphery, (or the inlet circle, as the case may be). Con-
sequently, as the fan revolves, the said rear edge is always in advance of the
radius above mentioned according to the size of the acute angle in the case, while,
and for the reason that the arc of the scoop has a larger radius than the outer one,
the leading edge if the scoop is still more in advance of the radius of the fan
intersecting the periphery of the fan at the point of junction of the said leading
edge with the said periphery.
The second part of my invention relates to continuing the inner blades of a
double fan outwards into the spaces between the outer blades.
The third part of my invention relates to double fans described above in which
there is a circular skeleton frame to which the outer and inner blades are made

page_text: fast and in which the ports are formed, said ports being narrower than the said.
frame. The side edges of the ports are, according to this part of my invention,
made up to the sides of the fan by fixed inclines or by approaching the side discs
to the said ports, which imparts to the ports an evasé contour to some extent and
prevents the formation of eddies.
The fourth part of my invention relates to providing a double type of fan with
evasé deliveries. This is done by making the sides of the fan diverge outwards.
The second and third parts of the invention are also applicable in combination
o a single fan.
In order that my invention and the means by which it is to be carried into
practical effect, may be thoroughly understood, I will now describe it and them in
letail, referring in so doing to the accompanying drawings which are to be taken
is part of this Specification and read therewith.

page_text: outer blade, and stands in advance of such radius' in 'the direction of the rotation
of the fan.
The exact angle at which an inner blade B' is set, with reference to a radius of
the fan, is found by describing an are having the same radius as the inlet circle E³
from the point H of intersection of the said circle by the junction of an outer and
an inner blade, and bisecting it by an arc G having the axis of the fan for a centre
and a radius = from 25 to 40 of the radius of the said inlet circle. Joining the
two intersections gives the position of the inner blade the side elevation of which is
represented by the line G H in Figure 1. This position is important as forming a
basis for that of my improved scoop. B³, B are the improved scoops in question.
Each one is made fast to the end of a blade and projects out laterally therefrom
through the inlet opening. The amount of such projection is proportional to the
length of the blade B or, in other words, to the width of a fan. In a'double fan,
the scoops are made fast to the inner blades. "The amount of projection illustrated
in Figure 2 may be taken as normal. A scoop is curved forwards in the direction
of the rotation of the fan. The-radius of the arc of the outer edge B' of a scoop
is shorter than that of the arc of the inner edge B, the scoop itself presenting the
appearance of a portion of the envelope of an inclined cone having its base parallel
with a diameter of the fan and its apex beyond the periphery of the latter. It
will be observed that this conformation of the scoops provides for the collection of
the air being done by them close to the axle C, or in other words by placing the
maximum scooping surface at the point of the scoop's lowest velocity. Further,
the outer edge B¹ is cut away to the arc of the inlet circle. The object in fixing
the inner blades and the scoops in the position with reference to a diameter of the
fan described and illustrated, is to provide planes inclined to the rear-speaking
with reference to the direction of rotation-up and over-which the air or water, as
the case may be, will flow smoothly towards the outer fan or towards the periphery
of the fan, according as it may be a double or a single fan to which the invention
is applied. It will be obvious, upon an examination of the organs of the invention,
as they are illustrated in Figure 1, that the improved conformation and disposition
of scoops must conduce-other things being equal-to a more rapid delivery than
could be effected by a combination of centrifugal energy and a truly radial blade and
scoop. It has already been explained that the ring F is not an essential feature
of the invention, and why. If a ring F fast to, and therefore revolving with, the
fan, be used, the outer ends B', B¹ of the scoops are joined thereto, thereby closing
those ends of the scoops. If, on the other hand, no-ring F is used, then the outer
ends of: the scoops are closed by suitable stop ends or by the surface within which
they revolve being brought close to them.
Referring to Figures 6 and 7, the modification illustrated therein consists in
setting the inner blades B, B2 at an angle with the axle C instead of parallel with
it. The ends next the inlet circle are in advance, in the direction of rotation, of
the opposite ends. The adjacent edges of an outer and an inner blade are joined
together by a triangular piece y bent transversely to the arc of the inlet circle E³.
Neither the above mentioned angular position of the blades nor the means of
joining the respectively adjacent edges of the outer and inner blades forms any part
of the present invention.
Referring to Figures 7 to 9, the features of invention illustrated therein
consist in
(a.) The-continuation of the inner blades B' of a double fan into the spaces
between the outer blades. This modification is illustrated in Figures 7 and '8
which shews the continuations e, e. Such continuations are preferably, as wide as
the fan, as illustrated in Figure 9. Each inner blade is joined to the outer blade
following it by a junction piece e' bent to the arc of the inlet circle or straight as
indicated by the dotted lines, or the inner blade may be set close to the said outer
blade as also indicated by the dotted line.
(b.) Filling in the internal angles between the sides of the ports A', A' and the
discs E, E¹ or the equivalent of the latter, by a fixed inclined piece which extends

page_text: from the side edge of a port up to the respective disc (or the equivalent of it) as
illustrated in Figure 8. The function of these filling pieces f, f, is to provide each
port with an evasé delivery in order that the formation of eddies in the_internal
angles above mentioned shall be obviated. It will be obvious that Figure 8
illustrates the use in a double fan of the circular skeleton frame described as a
cylinder in my former Patents 3131882, 31171883, and 87071801. When such a frame
is used, the ports A', A', are narrower than the frame thereby leading up to the
production of the internal angles above mentioned and the consequent eddies.
therein. It is to be understood that the same result may be attained by
approaching those portions of the discs on each side of the port close up to the
side edges thereof, all round the fan.
(c) Providing a single or a double fan with evasé deliveries. This is illustrated
in Figure 9 which shews a double fan having the ports A', A', as wide as itself.
The dotted lines shew how this part of my invention is carried into effect. The
discs E, E are made to diverge from the circle where the outer and inner blades
meet each other and the ports A', as indicated by the dotted lines, the outer
blades being made of the proper trapezoidal outline to follow the discs. This
divergence is equally applicable to fans in connection with which the discs are
replaced by fixed surfaces.
The combination of the divergent discs E, E¹ and the continuations e, e, of the
inner blades B³ may with advantage be added to a single fan made in other respects
according to the present invention.
Throughout the figures the direction of rotation is indicated by arrows.
Any of the constructions before described may be duplicated by placing two fans
with their closed sides back to back upon the same axle, thereby producing a duplex
fan having an inlet opening on each side.
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. The combination with the blades of a single fan, of scoops-one on the inlet
side edge of each blade-having the form specified, as set forth.
2. The combination with the inner blades of a double fan, of scoops--one on the
inlet side edge of each blade-having the form specified, as set forth.
3. The combination with the blades of a single fan, having their inner edges in
advance of a radius of the fan passing through their respective intersections of the
periphery of the fan, of scoops-one on the inlet side edge of each blade-having
the form and position specified, as set forth.
4. The combination with the inner blades of a double fan having their inner
edges in advance of a radius of the fan passing through their respective intersections
of the periphery of the inner fan, of scoops-one on the inlet side edge of each
blade having the form and position specified, as set forth.
5. The combination with the outer fan of a double fan, of continuations of the
blades of the inner fan into the said outer fan between the blades thereof, as set
forth.
6. The combination with the outer fau of a double fan, of continuations of the
blades of the inner fan into the said outer fan between the blades thereof, and
parallel side discs or the equivalent of the latter, as set forth.
7. The combination with the outer fan of a double fan, of parallel side discs or
the equivalent of the latter, continuations into the said outer fan between the blades
thereof and junction pieces from the continuations to the respective outer blades, as
set forth.
8. The combination with the outer fan of a double fan, of continuations of the
blades of the inner fan into the said outer fan between the blades thereof and
junction pieces from the continuations to the respective outer blades, as set
forth.
9. The combination with the ports of a double fan, of side discs or equivalent

page_text: surfaces inclined so as to make up to the side edges of the said ports, as set
forth.
10. The combination with the ports in the circular skeleton frame of a double
fan, of inclined filling pieces adapted to fill in the internal angles between the
sides of the ports and the discs or the equivalent of the latter, as set forth.
11. The combination with the ports in the circular skeleton frame of a double
fan, of side discs inclined towards each other at their junction with the said frame,
so as to coincide with the side edges of the ports, as set forth.
12. The combination with a double fan of divergent side discs or equivalent
surfaces, as set forth.
13. The combination in a single fan, of curved or straight blades, scoops of the
form specified, divergent discs or the equivalent of the latter and continuations of
the blades standing between them, as set forth.
14. The combination in a single fan, of curved or straight blades, scoops of the
form and in the position specified, divergent discs or the equivalent of the latter,
and continuations of the blades standing between them, as set forth.
15. The combination in a single fan, of curved or straight blades set at an angle
with the axle, scoops of the form and in the position specified, divergent discs or
the equivalent of the latter and continuations of the blades standing between them,
as set forth.
16. The combination in a single fan, of curved or straight blades set at an angle
or parallel with the axle and making an acute angle with a radius of the fan
intersecting the periphery thereof at the point of junction of the said blades
therewith, scoops of the form and in the position specified, divergent discs or the
equivalent of the latter, and continuations of the blades standing between them,
as set forth.
17. The combination in a double fan, of curved or straight inner blades, scoops
of the form specified, divergent discs or the equivalent of the latter, and
continuations of the inner blades standing between the said discs and the outer
blades, as set forth.
18. The combination in a double fan, of curved or straight blades, scoops of the
form and in the position specified, divergent discs or the equivalent of the latter,
and continuations of the inner blades standing between the said discs and the outer
blades, as set forth.
19. The combination in a double fan, of curved or straight blades set at an angle
with the axle, scoops of the form and in the position specified, divergent discs or
the equivalent of the latter and continuations of the inner blades standing between
the said discs and the outer blades, as set forth.
20. The combination in a double fan, of curved or straight blades set at an angle
or parallel with the axle and making an acute angle with a radius of the fan
intersecting the inlet circle thereof at the point of junction of the outer and inner
blades, scoops of the form and in the position specified, divergent discs or the
equivalent of the latter and continuations of the blades standing between the said
discs and the outer blades, as set forth.
Dated:
1
PHILLIPS & LEIGH,
No. 22, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.