Improvements in Ventilators or Blowers.
Year: 1894

page_text: Date of Application, 18th May, 1894-Accepted, 23rd June,
1894
Improvements in Ventilators or Blowers.
A communication from EDOUARD HOCHHEIM, Mechanical Engineer, M. Gladbach,
Germany.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
Chartered Patent Agent, 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 :-
This invention has for its object the creation of a new system and type of
improved ventilator based upon a new form and arrangement of vane, by which it
is distinguished from all other appliances of the kind hitherto known.
The vanes are curvilinear so as to form three curved surfaces joined together by
two voussures or covings; and there are consequently three suction-surfaces in
action.
The particular construction of these improved vanes and the mode of fixing
them on the ventilator-shaft, are illustrated on the accompanying drawings,
wherein
Figure 1 is a front view of the ventilator showing the form of and mode of
mounting the vanes as seen from the side on which the air is drawn in.
Figure 2 is a back view of the ventilator showing the form of and mode of
mounting the vanes, as seen from the side on which the air is delivered or
forced out.
Figure 3 is a vertical section of the ventilator on the axial line of the shaft
showing the configuration of the total active surface of suction or inspiration,
limited by the surfaces of the vanes and the plane of the ventilator wheel
or disc.
The vanes A are secured to the curved radial arms B and to the rim of the
wheel which is firmly secured to the hub or hoss D by the said radial arms B..
The total active inspiration or suction surface S (Figure 3) is formed by
the three faces of the vane bed which are united the one to the other by
the two voussures vw and by the plane a of the wheel. The voussures or
covings vw may assume a form less rounded than that shown in Figure 3,
.e. the b and c as well as d and c may be joined together by sharper curves.
will be observed that, according to the drawings the entire volume of air that is
imprisoned, by the advance of the vane, between the four surfaces a b c d can
escape freely without any hindrance or difficulty, by the open surface a or in other
words, by the intervals between two successive radial arms of the wheel.
It
Further it will also be remarked that the suction or effect of inspiration of air
of the vanes is nowhere hindered by any intermediate or accessory constructive
parts of the ventilator, and thus the entire annular space corresponding to the
diameter of the hub D is open and free on the side where the action of inspiration
or suction takes place.
In practice, experiment has demonstrated that the suction or inspiration of a
ventilator fan or blower more energetic at the centre than at the circumference
wherefore the above-described arrangement of the vanes is particularly advan-
tageous, and the result obtained shows actually an increase of 20 per cent. in the
yield or efficiency of this improved ventilator, as compared with others of different
construction tested under the same conditions of working and load.
It will also be readily understood that an advantage results from the form and

page_text: arrangement of the vanes themselves which by reason of the double voussures
or covings are self-centring to as great an extent as if by a special constructive
device to that end, wherefore they may be made of only half the weight and
strength of similar parts as hitherto constructed for exactly the same work.
The essential feature of the present improvements consists therefore in the
increased power of suction or inspiration of the vanes, owing to their special form
and arrangement, which allows a free passage to the air in direct proximity to the
ventilator shaft (as indicated by the arrows in Figure 3) where the action of the
ventilator is most powerful and effective.
The improved type of ventilator hereinbefore described, has moreover the great
and important advantage that it is particularly adapted to combine for the purpose
of duplicating the fan or blower whereby the ventilating power can be increased
without any augmentation in the diameter of the operative vane-wheel.
It frequently happens that in large public halls or other enclosed places or
structures, such as factories, mines steamships etc. there is very considerable volume
of air which must be set and kept in motion, necessitating great suction and forcing
power, such as can only be obtained by means of fans of large dimensions, which
are in themselves the cause of trouble and embarrassment, on account of the heavy
masses in motion and the great sacrifice of space necessary.
By combining two fans or blowers with vane-wheels in one ventilator or
apparatus, having the same diameter, double the quantity of air can be drawn out
of a given enclosed space in the same time whereby the evil above-mentioned is
advantageously obviated.
Figure 4 is an elevation of a double ventilator from the point of view of the
common axis.
Figure 5 is a horizontal section of the apparatus.
Two ventilators with vane-wheels are mounted and keyed on one and the same
driving shaft X; A designates the vanes, whereof only one is shown in Figure 4,
in order to avoid complication of the drawing, all the vanes being secured to the
curved radial arms B which unite the rim C to the hub D.
In Figure 5 the vanes present horizontally their total inspiratory surface
formed of the surfaces bed and of the plane a of the vane-wheel.
As shown by the arrows the air is drawn in over the entire developed surface
and finds free vent towards the central interior of the apparatus V.
The vane-wheel consisting of the shaft X, the hub D, the arms B, the vanes A,
and the rim C, rotates inside the frame or casing F. The two casings F
appertaining to the two fans are firmly united together in suitable manner as by
tie bars passing through the openings R.
The case F is prolonged in the upward direction and secured to a girder in the
ceiling or to some other fixed part for which purpose it may be provided with
flanges s. The part T serves as the outlet.
For the purpose of forming a receptacle, closed on all sides excepting at the
place intended to provide an outlet for the escape of the air, a preferably sheet
iron casing J is secured to the flanges G.
In the middle of the receptacle V a separating partition L is arranged and
secured to the outer casing J by means of angle-irons M the shaft ✗ passing
freely through the centre of the partition, which is intended to prevent the action
of either of the fans from prejudicially affecting that of the other, by setting up
any air currents or eddies by reason of any inequality in the working or in the
conditions of inspiration on either side.
In the drawings the vanes as shown are arranged on the outer side of the fan,
but they may equally well be fixed on the inner side in which case the air would
be exhausted from the interior of the receptacle V instead of being forced or
drawn into it as in the case shown in the drawings 4 and 5 by the ventilator
fans.
It will be observed that by means of the combination described and illustrated
it is possible to set in motion double the quantity of air that a single ventilator

page_text: of given diameter could influence, without the necessity of increasing the diameter
of the fan or the speed of its rotary movement.
This improved arrangement therefore offers great advantages in all the
numerous cases where it would be impossible to enlarge the inlet or outlet of the
current or column of air drawn in and forced out by the single ventilator fan
hitherto employed.
Having now particularly described and ascertained the nature of the said inven-
tion as communicated to me by my foreign correspondent, and in what manner the
same is to be performed, I declare that what I claim is :-
1. The particular construction of the vanes with double voussures or covings A.
secured to the rim C and to the curved radial (helicoidal) arms B characterized
by the two active inspiration surfaces b and c having added to them a third such
surface which being arranged directly with regard to the shaft draws the air in to
the centre of the fan and thence conveys it freely to the exterior in such manner
that the yield or useful effect is augmented and that at the same time the vanes.
can be made lighter substantially as described and illustrated in the accompanying
drawings.
2. The combination of two ventilator fans of equal diameter to form a double
blower for the purpose of duplicating the power of a single ventilator without
increase in either the diameter or speed of rotation characterized by the connecting
of two frames or casings such as F to form a closed receptacle within which are
arranged to rotate two vane-wheels such as A B C D secured on one common.
shaft substantially as described and illustrated in the accompanying drawings.
3. In the combination described in Claim 2 the arrangement of a separating
partition L in the middle of the receptacle V to ensure the regular and
independent working of each of the two ventilator fans or blowers and the
formation of an air discharge outlet common to both blowers by the prolongation T
of the receptacle V substantially as described and illustrated in the accompanying
drawings.
4. In the combination described in Claim 2 the arrangement of the vanes A
secured to the curved radial ribs or arms B and rim C either outside or inside the
receptacle V in such manner that the air may be drawn in by inspiration by means.
of the three surfaces bed and expelled freely by the fourth surface either inwardly
or outwardly substantially as described and illustrated in the accompanying
drawings.
Dated this 18th day of May 1894
W. P. THOMPSON & BOULT,
Agents for the Applicant.