Year: 1887

page_text: Date of Application, 10th Oct., 1887
Complete Specification Left, 9th July, 1888
Complete Specification Accepted, 10th Oct., 1888
I, FRIEDRICH PELZER, of the town of Dortmund in the German Empire, Engineer,
do hereby declare the nature of my said invention to be as follows:-
My invention relates to an improved turbine or centrifugal ventilator as represented
in rear view and section in Fig. 1 and 2 and in diagram in Fig. 3, which is perfectly
closed on the one side by a suitable cone, whilst the opposite side into which the air
to be exhausted flows is provided with turbine wings, K, K, i, I, part of which said
wings are surrounded by a cylindrical or conical ring, b, b'. In manufacturing my
improved centrifugal ventilator, sheet metal lugs are rivetted at I, K, Fig. 2, to the
edge of each arm or wing and bent to an angle corresponding to the position the said
wings are to occupy, and then a cylindrical or conical ring 61 laid around the
edges K, K, of the turbine wing and attached to the said wings on the line b', c.
The surfaces of the wings K, Kil are as shewn in Fig. 1 and 2 plane or almost
so, but if in employing this construction of the wings the indrawn air flows into
the ventilator in nearly axial direction, it will impinge on those parts of the surface of
the wings K, K, i, I, which lays correspondingly near to the axial centre and which
rotate at proportionately lesser speed on the outer surface of the turbine wings and
is thereby led off at the side opposite to that of the rotating direction of the ventilator.
In consequence of the latter, as well as the striking against the outer surface of the
turbine wings loss of power is produced.
In such ventilators that are to generate great differences of tension, it is necessary,
if the size of the ring of the turbine wings is not to be reduced to a minimum and
the width of the cylindrical or conical ring b. a Fig. 1 is not to be made unpro-
portionately broad, so that the turbine wings overlap each other, in consequence of
which the aforementioned disadvantage of the indrawn air impinging against the
surfaces of the outer turbine wings, would be increased.
To entirely surmount this difficulty it is necessary to construct the turbine wings
in such a manner that when the ventilator is in operation, each of the elements of their

page_text: surfaces makes room for the next so rapidly that the air flowing through in axial
direction cannot reach the outer surface of the turbine wings.
As the speed of the elements or different parts of the surfaces of the separate
turbine wings decreases evenly from their outer circumference to the axial centre,
where it is reduced to zero, it is necessary (conforming to the above conditions) to
give them such a curved shape as to allow them to have such same plane as the
ventilator wings would have if the former were lengthened to the axial centre, whereas
the curvilinear form towards the periphery is such that, as above mentioned, the air
flowing through the ventilator in axial direction cannot reach the outer surfaces of the
said turbine wings.
Such a surface can be constructed in the following manner (for greater clearness
sake I have referred to the accompanying drawings in order to explain the method of
construction):
Given the velocity of the indrawn air into the ventilator at a known number of
revolutions of the same. Now imagine a plane rectangular to the axis of the ventilator
and a considerable number of cylindrical mantles laid around the said axis con-
centrically, the diameters of which mantles, d¹ d³ d³ etc. increase uniformly. These
cylindrical mantles shall cross the turbine wings as well as the plane rectangular to
the ventilator axis, as mentioned above. c, d Fig. 2, denote the projection of the width
of the turbine wing on a plane which coincides with the plane of the respective
ventilator wing and G, 113 etc. denote the projections of the concentrical lines which
are formed by the cylinder planes, d' d² d³ etc., with the turbine wings on a plane F. B. C.
Fig. 3, vertical to the ventilator axis.
Under these circumstances ¹¹, d¹, if ¹ represents the number of revolutions
in the time t. During the same time a particle of the air drawn in an axial direction
into the ventilator covers the space v t = c d.
By help of these data the surface of the turbine wings can easily be modelled in
the well-known manner by drawing the circles with their diameters d' d' d³ etc. on a
suitable smooth section F. B. C, of a cylinder, Fig. 3, which is placed rectangular to
the axis of the ventilator, and is made of appropriate material, such as wood, Plaster
of Paris etc., which circles form the aforementioned sectional lines. Of the two planes
by which the cylinder section is bounded, the one A B C D whose sectional lines
form the cylinder axis A B, is to come to the same level as the plane of the ventilator
wings, whose turbine wing like surface is to be modelled. If then, a part revolution
of the ventilator takes place equal to the angle C B. H, in the time t, the circles 11 ľ³
etc. are the projections of the sectional lines 1, 12, 13, which the cylinder surfaces
and their diameters d¹ d² d³ etc. form with the turbine wing like surfaces. It is
assumed that the projection c d of the width of the turbine wing from H to B has
the same dimensions Fig. 3. When the given incline which is formed by the
ventilator wing with the turbine wing like surface and which is shown by a straight
line, has been ascertained on the plane A B (D, a requisite number of dots can
be marked on the surface of the turbine like wing in process of modelling by
making a number of equi-distant perforations in the above mentioned circular
mantles 11, 12, 13. These perforations are to be assumed as being bored so that
their depth at the intersection of these circles 13 etc. form the line or inter-
section of the tubine and ventilator wings I K. At the crossing points of the
said circles with the line B H, perforations are also to be bored whose depth
is increased a distance c d, equal to the projection of the width of the turbine
wing more than the corresponding holes on the other end of the said circles.
These then show the line i k. Between these two rows of perforations at the ends
of the circles, a great quantity of equidistant perforations are arranged in such
manner that the difference of depth of each adjoining perforation of the same
circle 13 etc. is equal. By removing the material above the ends of the per-
forations so as to produce a gradual transition of the surface, the exact shape of the
turbine wing is obtained.
In practice it suffices to construct the shape of said wings only approximately
according to above instructions.

page_text: I do not restrict these my improvements mentioned to atmospheric and gaseous
bodies, but everything advantageous found in my improvements for the above bodies
is equally so for denser bodies, such as water and similar fluids.
The above construction of turbine wings can also be advantageously used in the
construction of centrifugal pumps.
ALLISON BROS.,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Centrifugal Ventilators and Pumps.
I, FRIEDRICH PELZER, of the town of Dortmund in the German Empire, Engineer,
do hereby declare the nature of my invention for "IMPROVEMENTS IN CENTRI-
FUGAL VENTILATORS AND PUMPS" 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 an improved turbine or centrifugal ventilator as represented
in rear view and section in Figs. 1 and 2, which is perfectly closed on the one side by
a suitable cone, whilst the opposite side into which the air to be exhausted flows is
provided with turbine wings Kki I which said wings are surrounded by a cylinder or
conical ring bb¹.
In manufacturing my improved centrifugal ventilator sheet metal wings are rivetted
at I K Fig. 2 to the edge of each blade and bent to an angle corresponding to the
position the said wings are to occupy, and then a cylindrical or conical ring bb' is
laid around the edges Kk of the turbine wings and attached to the said wings on the
line b¹ c.
If the surfaces of the wings Kk iI are plane or almost so, the indrawn air will
flow into the ventilator in nearly axial direction, and will impinge on those parts of
the surface of the wings K, k, i, I, which lie correspondingly near to the axial centre
and rotate at proportionately lesser speed than the outer surface of the turbine wings,
and be led off at the side opposite to that of the rotating direction of the ventilator.
In consequence of this, and owing to the said indrawn air striking against the outer
surface of the turbine wings, loss of power is produced.
In such ventilators that are to generate great differences of tension, it is necessary,
(if the size of the ring R of the turbine wings is not to be reduced to a minimum
and the width of the cylindrical or conical ring b, a, Fig. 1, is not to be made unpro-
portionately broad,) that the turbine wings overlap each other in consequence of which
the aforementioned disadvantage of the indrawn air impinging against the surfaces of
the outer turbine wings would be increased.

page_text: To entirely surmount this difficulty it is necessary to construct the turbine wings in
such manner that when the ventilator is in operation each of the parts of their surfaces
makes room for the next so rapidly that the air flowing through in axial direction
cannot reach the outer surface of the turbine wings.
As the speed of the elements or different parts of the surfaces of the separate
turbine wings decreases evenly from their outer circumference to the axial centre
where the said speed is reduced to zero, it is necessary (conforming to the above
described construction) to give them such a curved shape that they would have the
same plane as ventilator blades if the turbine wings were extended to the axial centre,
whereas the curvilinear form towards the periphery is such that as above mentioned
the air flowing through the ventilator in axial direction cannot reach the outer surfaces
of the said turbine wings.
These conditions will be fulfilled by constructing the turbine wings in such manner
that they, in the proximity of the ventilator axis, form with the plane of the corre-
sponding ventilator blade a very acute angle and that this angle on the periphery of
the ventilator will gradually be increased and become the greatest at the extreme end
of the turbine wings.
Fig. 3 is a view of a flat side of a turbine wing constructed according to my inven-
tion and Fig. 4 represents a sectional diagram of the turbine wing and the corre-
sponding ventilator blade F-F. The section m, n, is the nearest to the circumference
of the ventilator, whilst the remaining sections, o, p, q, r, s, t, u, v, are taken in equal
distances towards the axis of the ventilator. The angle, which is formed by the
sections of the turbine wings with the blades of the ventilator decreases from m, n, to u, v,
as shown in Figure 4; said angle would disappear if the turbine wing could be
continued to the centre of the axis.
I desire it to be understood that I do not restrict my said improvements to atmo-
spheric and gaseous bodies, as it will be evident that my said invention can also be
appropriated with like advantage for denser bodies, such as water and similar fluids.
The above construction of turbine wings can also be advantageously used in the
construction of centrifugal pumps.
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 :
The construction of lateral turbine wings for centrifugal ventilators and centrifugal
pumps in such manner that said wings form the greatest angle at their circumference b,
Figure 2 and m, n, Figures 3 and 4, with the corresponding ventilator blade F whilst
their surfaces so decrease that the aforementioned angle gradually diminishes towards
the axis of the blade substantially as described in the foregoing specification and
shown in the accompanying drawings.
Dated this 9th day of July 1888