Note: Descriptions are shown in the official language in which they were submitted.
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wO 2007/045288 PCT/EP2006/006686
ROTOR FOR A ROTARY MACHINE AND A ROTARY MACHINE
The invention relates to a rotor for a rotary machine
according t.o the preamble of claim 1 and to a rotary
machine according to the preamble of claim 11.,
Rotary machines are distinguished in that they produce
a pressuze difference in a gaseous or liquid medium or
are driven by a pressure difference in a medium of this
type. For this purpose, xotary machines of this type
generally have a rotor which is rotatably mounted in
the gaseous or liquid medium relative to a st.ator and
produces, by way of its shape or arrangement, a
pressure difference or converts the pressure difference
in the medium into a rotational. movement., Examples of
rotary machines of this type include, in the first
place, most. types of pumps, compressors, turbomachines,
t.urbines or wind energy converters which have a broad
range of designs of rotors and are usually rotatably
mounted in a housing as a stator.DD 293 181 A5 discloses a rot.ary machine in
the form of
a pump having a cylindrical or conical rotor which is
eccentrically mounted in a pump housing.. This rotor is
connected to a drive and produces on rotation a
crescent-shaped revolving pump chamber which conveys
preferably oil as a liquid fxom an inlet opening into
an outlet opening.. This pump, which is based ori the
hydrodynamic principle, produces during rotaticri in the
crescent-shaped revolving housing an oil wedge which
leads to a rise in pressure in the pump chambes and
thus conveys the oil from the inlet opening into the
outlet opening.. In this case, the rotor has a
zelatively smooth round outer lat.eral surface which
produces the rise in pressure in the liquid exclusively
owing to its eccentric path of revolution..
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Nevertheless, an eccentrically revolving rotor of this
type in a cylindrical housing is hardly suitable, owing
to its unstzuctured lateral surface, in a gaseous
medium in the pump chamber..
DE 103 19 003 Al discloses a rotor of a wind energy
converter by means of which wind energy is converted
into electzical energy.. In this case, the rotors
consist of a shaft which is mounted in a st.ator and on
which outwardly projecting rotor blades are arranged at
constant-angle intervals.. The rotoi blades are in this
case formed as a symmetrical wing of an airfoil of an
aircraft. t.hat possesses in the flow direction a
cylindrical lat.ezal surface and accordingly has a
convex prot.rusion which tapers to the rear at an acute
angle., The rotor blades are in this case oriented in
the wi.nd direction in such a way that the wind which
sweeps past brings about, as a gaseous medium and in
accordance with Bernoulli's equation, a pzessuze
difference which causes rotational movement of the
mounted rotor in the stator. As a wing of this type
causes on its edge which tapers at an acute angle a
disruptive eddy formation, indentations are provided on
the wing profile transversely to the wind direction.
This gives rise to a lower pressure on the upper side
than on the underside, leading to additional lift, as a
result of which the eddy formation is reduced and more
efficient energy conversion should be possib].e..
However, a rotor of this type is provided exclusively
for use in aeriform or gaseous media and, owing to its
long rotor blades and the housing diameter necessitated
thereby, can hardly be used with liquid media,.
DE 42 23 965 Al discloses a tuzbomachine zotor in which
at. least one support disk is mounted on a mounted shaft
and on the outer cylindrical lateral surface of which
are arranged projecting short blades which revolve in a
gaseous medium.. This rotor is arranged in a stator
housing and is driven via the shaft at. a high
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zotational speed.. In this case, the gaseous medium is
pressed from an inlet. opening into an outlet opening
with a high condensing effect.. Nevertheless, a
turbomachine zotor of this type is generally not
suitable for liquid media, as such media are non-
compressible, so the thin blades could easily become
damaged..
DE 197 19 692 Al discloses a rotor pump which comprises
an internally toothed zotor and has a very robust
design of an internally toothed zot.or.. In this case,
the pump consists of a housing containing a rotatable
eccentric ring in which an outer impeller and an inner
impeller axe rotatably mounted.. In this case, the inner
impeller is an inner rotor which has a plurality of
teeth arranged on its outer lateral surface and is
rot.atably arranged in an outer YotoY.. The outer rotor
encloses the inner rotoz with its inner lateral surface
on which inwardly directed teeth are likewise arranged,
In this case, bot.h the inner and t,he outer teeth extend
over the entire length of the lateral surface and
consist substantially of a convex symmetrical
elevation, six convex elevations being arranged on the
outer lateral surface of t.he inner rotor and seven
convex elevations being arranged on the inner lateral
suzface of the outer rotoz. The inner cavity of the
outer rotor is in this case respectively connected to
an inlet opening and an outlet opening which oppose
each othez.. The rotational movement of the inner rotor
also gives rise to a rotational movement of the outer
rotor in the eccent1 ic ring, thus forming a series of
chambers having variable volumes between the teeth of
the inner and outer rotor.. As a result, a fluid located
in the chambers is drawn into the expanding chambers
and out of the contracting chambers.. The fluid provided
is in this case a hydraulic liquid which is pressed
from the inlet, opening int.o the outlet opening as a
result of the pzessure differences t.hus produced.. As a
rotor of this type consists of at. least two toothed
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part.s which are arranged coaxially with one another and
must also have a differing number of teeth and mesh
with one another with a precise fit only when designed
with maximum precision, a rotor arrangement of this
type is highly complex to manufacture and equipped with
a number of parts which are subject to frictiorl and
dependent. on weaY.
The invention is therefore based on the object. of
providing a univezsally usable rotor for a large number
of designs of rotary machines that. is robust and almost
maintenance-free while at the same time being simple to
manufacture..
This object is achieved by the invention disclosed in
claims 1 and 11. Developments and advantageous
exemplary embodiments of the invention are disclosed in
the sub-claims.,
The invention has the advantage that, as a result of
the airfoil profile on one of the lateral surfaces of
the rotos, owing to the Bernoulli effect resulting from
the movement. of the rotor or the flow of a gaseous oz
liquid medium, a reduced pressure effect is produced
above the airfoil profile, thus allowing a rotor of
this type to be used in zotary machines both for liquid
and for gaseous media, As the pressure or suction
effect is not produced by t.he formation of revolving
sealing chambers, a medium laced with solids can thus
advantageously also be conveyed, so rotors of this type
are also highly suitable for continuous conveyance of
bulk materials or dispersions..
At the same time, the invention has the advantage t.hat
the flow-beneficial airfoil profile gives rise to only
slight eddy formation in the medium used and, apart
from the bearings, there is no contact with a statox or
other rotor pazts, so zotazy machines which are
equipped with a rotor of this type operate particularly
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quietly and display almost no flow or frictional
losses. As the rotor according to the invention is
internally hollow and produces the pressure diffezence
merely by way of a flat airfoil profile on one of the
lateral surfaces, t.he rotor can be manufactured so as
t.o be particularly light, so only low masses have to be
accelerated, thus as a whole advantageously allowing a
highly efficient rotary machine to be achieved, the low
friction and the low flow t.urbulences notwithstanding..
In addition, the low rot.or mass and the substantially
symmetYical formation and centzic rotation give rise to
only low centrifugal force effects, so a rotor of this
type can advantageously be opezated at high rotational
speeds., This allows even high pressure differences at
high flow speeds to be produced, as a result of which
high outputs of the gaseous or liquid medium provided
or of the solids contained therein can at t.he same time
advantageously be achieved..
As the producible pressure difference rises, in a rotor
sleeve profiled in accordance with the invention in
this way, almost proportionally to the rotational
speed, almost no pressure or volume fluctuations can
advantageously occur at a const.arit. rotor speed. The
airfoil profile on the lateral sleeve produces, when
the motoz is being driven, at all times a pressure
difference which is independent of the ambient pressure
of the medium, thus advantageously allowing even high-
density gaseous media to be conveyed or liquids from a
very low dept.h to be pumped to the surface on
application of static pressure..
The rotor according to the inventiorr and a rotary
machine equipped therewith can not only be utilized in
the driven state for conveyance oz producing pressure
but can also be used, on flow-correct. introduction of a
pressuzized medium, to produce rotational speed in
order to produce energy, such as for example
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electricity, advantageously from water power or wind
power..
In a multistage formation of the rotor according to the
invention and a rotary machine equipped therewith,
higher pressures can, in the case of axial stages and
at a constant flow rate, advantageously be produced or,
in the case of coaxial stages, the raising of the
pzofile surface, while the pressure difference remains
constant, advantageously allows still higher flow zates
to be conveyed..
The invention will be desczibed hereinafter in greater
detail with reference to an exemplary embodiment
illustrated in the drawings, in which:
Fig.. 1 is a perspective view of a pump comprising a
single-stage pump rotor;
Fig.. 2 is a front view of the pump comprising the pump
rotor;
Fig. 3 is a plan view of the pump comprising the pump
rotor;
Fig. 4 shows a lamella ring of an impeller for the pump
rotor;
Fig.. 5 shows an arrangement of lamella elements of an
impeller for t.he pump rotor;
Fig,. 6 is a sectional view of a pump comprising a
multistage pump rotor; and
Fig.. 7 is a sect.ional view of a drive turbineõ
Fig.. 1 of the drawings is a perspective view of, as the
rotary machine, a pump 1 having a single-stage hollow
rotor 2, as a pump rotoz, which has on an outer lateral
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surface 4 nine airfoil profile elements 3 between which
passage openings 5 to the inner cavit.y 6 aze arranged.
The pump 2 shown is a design which is opexated
preferably with water as a liquid medium.. The pump 2
consists substantially of a stationary housing 7 as the
stator, in which the pump rotor 2 is arranged. The
rotor is, in the housing 7, rotatably mounted in t.wo
bearings 8 and has in its center a shaft 9 which is
connected to a drive motor 9 (not shown). The housing 7
is substantially cylindrical in its formation and
contains on its outer lateral surface an outlet opening
11 for removing the water to be pumped., An inlet
opening 10, which is connectable to a feed line (not
shown), is provided on the left-hand end face or
lateral surface of the housing 7 to allow the water to
be pumped to enter the cavity 6.. The inlet opening 10
is connected to the cavity 6 of the rotox 2 and forms
therewith an inlet chamber 12,. A pump 1 of this type
can in principle be used to convey al1 liquid media,
such as for example water, oil and the like, and also
all liquids which are mixed with solids, such as for
example dispersions..
Fig.. 2 of the drawings is a front view, showing in
detail also the arrangement and formation of the rotor
2, of the pump 1 described hereinbefore.. In this case,
the rotor 2 consists substantially of a cylindrical
impeller 20 which has on the inside a cylindrical
cavity 6 which, in the case of the pump 1 shown, forms
an inlet chamber 12.. Nine convex elevations 3, which
form an axially extending airfoil profile on the outer
tangential lateral surface 4 of the rotor 2, are
arranged on the outer lateral surface 4 of the rotor 2,
distributed in identical angular port.ions.. As the rotor=
2 has on its outer t.angential lateral surface 4 a
plurality of airfoil profile elements 3 which, on
rotation, form, as a result of the Bernoulli effect, a
reduced pressure region even in gaseous media such as
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for example air, all gaseous media, such as gaseous
media permeated with bulk materials, can thus also be
conveyed, condensed or drawn in..
Passage openings 5 to the inner cavity 6 or to the
inlet chamber 12 of the pump 1, which contains the
medium to be pumped such as for example water, are
provided in the end region of the airfoil profile 3.
Fig. 3 of the drawings is a detailed plan view of the
axial formation of the pump 1.. Fig.. 3 of the drawings
reveals that the rotor 2 is lamellar in its
construction in the axial direction.. These lamellae
are, owing to the airfoil profile 3 made of flat metal
sheets, preferably cut out or punched out with the aid
of a laser. In this case, the Yot.oY 2 consists mainly
of lamella rings 13 and an airangement of lamella
elements 14 which form the impeller 20.
Fig. 4 of the drawings is a more detailed view of the
lamella rings 13 and Fig.. 5 of the drawings is a more
detailed view of the lamella elements 14 which, as an
axial pack of lamellae, form the impeller 20 with the
tangential lateral surfaces 4,. The rotor 1 shown in
Fig. 3 of the drawings consists of three arrangements
of lamella elements 14 and a respective lamella ring 13
is fastened to its outer lateral surfaces. In this
case, the lamella ring 13 preferably consists of a flat
steel sheet which is protected against corrosion caused
by aqueous liquids or consists of a stainless high-
gzade steel. Both t.he lamella rings 13 and the lamella
elements 14 aie usually made of the same material
which, depending orl the medium used, can also consist
of other metals, hard plastics materials, synthetic
fiber composite materials oY ceramics.. Each lamella
zing 13 has on the inside a circular hole 23 having a
diameter of, for example, 250 mm and a smallest outeY
diameter of approx. 360 mm.. Ir1 this case, the lamella
ring 13 contains prefexably nine similar angular
regions, each of 40 , and has arzanged on its outer
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t.angential lateral surface 4 in each case a convex
elevation 19 which, counter to the direction of
rotation 18, merges flat. at a descending inclination
with a run-out region 24 and forms an airfoil profile
3. The convex elevation 19 has relative to the running-
out end preferably an elevation 19 of approx. 45 mm and
possesses a radius of approx.. 20 mm. The descending
profile region 24, which runs out counter to the
direction of rotation 18, has a concave curvatuze with
a radius of 167 mm and extends over a length of approx..
70 mm.. The convex elevation 19 with the descending
concave running-out region 24 thus imitates on the
latezal surface 4 a profile of an airfoil wing of
aircraft. The airfoil profile 3 ends in this case in a
slightly rising tip 25 which acts as a spoiler and
substantially prevents turbulences on the tear-off
edge.
The turbulence-preventing tip 25 is followed, counter
to the direction of rotation 18, by a tangential
straight surface which is at the shortest distance from
the axis of rotation 26 and extends tangentially
thereto over a length of approx,. 5 mm.. This straight
surface delimits the passage openings 5 in the axial
direction and terminat.es each individual airfoil
profile 3 on the tangential outer lateral surface 4 of
the rotor 2.. In this case, each lamella ring 13 is
formed by preferably similar airfoil profiles 3 which
are arranged in identical angular regions and at the
same distance from the axis of rotation 26.,
Arranged between two outer lamella zings 13 are, to
embody the pump rotor 2 shown, three lamella layers of
in each case nine lamella elements 14 which on their
outer radial edges also have the same airfoil profile 3
as the lamella rings 13. To form an impeller 20 of a
rotoz 2, the individual lamella elements 14 are
connected, in congruent alignment with the airfoil
profile 3, to a lamella ring 13 or to other lamella
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arrangements and accordingly constitute an axial
impeller or an impeller part. which forms on it.s outer
tangential lat.eral surface 4 a uniform, axially
oriented airfoil profile 3, In this case, the lamella
elements 14 are however arranged tangentially set apart
from one another and connected as a whole to the
lamella rings 13, the distance between the lamella
elements forming a passage opening 5 through which the
medium provided is drawn outward by suction from the
inner cylindrical cavity 6, as a result of the reduced
pressure, along the descending airfoil profile 3, owing
to the Bernoulli effect...
For the flow-beneficial formation of these passage
openings 5, the individual lamella elements 14 are
provided in their rear region with a convex curvature
15 and in their front region with a concave curvature
16 which allow a substantially eddy-free flow during
the rotation.. In this case, t.he concave curvature 15 on
the inner edge also merges with a concave curvature
which corres-oonds to the radius of the hole 23 in the
lamella ring 13 of, for example, 125 mm.. As a result,
the rotor 2 forms on the inside an axially continuous
cylindrical cavity 6 as the inlet chamber 12.
Star-shaped connecting elements, which are connected to
the drive shaft 9 in a torsionally rigid manner and
preferably to at. least one of the lamella rings 13, are
provided for fastening the impeller 20 to the drive
shaft 9.. In another embodiment. of the invention, the
airfoil profile 3 can also be arranged on the inner
tangential lateral surface, the rotor 2 t.hen having on
the outside a circular lateral surface 4, as a result
of which the direction of flow is reversed and the
outlet chamber 21 is fozmed in the cavity 6 of the
impeller 20 or of the rotor 2..
For operating the pump 1, the rotor 2 is driven at a
predet.exmined rotational speed and in a predetermined
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direction of rotation 18, so a reduced pressure or
difference in pxessure fYom the surrounding gaseous or
liquid medium forms on the outer lateral surface 4 in
the direction of rotation 18 after the convex elevation
19 in accordance with the Bernoulli effect, so the
medium is drawn outward out of the inner chamber 6 in
which the pressure is higher., In this case, the
pressure difference depends substantially on the
rotational speed or the circumferential speed of the
impeller 20. The pressure difference rises
approximately linearly until the eddy formation on t.he
tear-off edge or other tuzbulence elements becomes so
great as to yield a significant counterpressure.. This
can however be reduced by an advantageous formation, in
particular, of the torn-off edge and by the formation
of a circular inlet 12 and outlet chambers 21, so at
rotational speeds of at least. 10,000 rpm the pressure
rises linearly..
A high pressure difference can at the same time also
allow an increase in the flow rate per unit of time,
although this is limited by the cross-sectional surface
areas of the passage openings 5. Nevertheless, the flow
rate or t.he flow volume can easily be increased also by
enlarging the surface area of the airfoil profile 3.. In
principle, a pressure difference can be produced with
just one airfoil profile 3 on the circumference of the
rotor 2 or of the impeller 20õ Nevertheless, to
increase the flow rate and to improve the flow ratio,
nine airfoil profiles 3 were preferably arranged
circularly around the tangential outer rotor sleeve 4,
although both a smaller and a larger number of profile
surfaces can also be embodied.. A rot.or 2 of this type
comprising at. least one airfoil profile 3 does not have
to be cylindrical but can zather also have a spherical
or conical outer lateral surface 4 by means of which a
pressure difference can also be produced.. In this case,
a rotor of this type does not require any closed-off
inlet 12 or outlet chambers 21 either, as simply
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rotation within a gaseous or liquid medium without a
housing part. reduces a pressure difference which can be
ut.ilized merely by means of a discharge or feed line
which must be connected merely to one of the inlet 12
or outlet chambers 21.. In this case, the possibility of
utilizing the pressure compensation determines
substantially the design of the rotary machineõ Thus, a
rotary machine having a closed-off inlet chamber
connected to a line as a suction machine can also be
formed for gaseous media or as a vacuum cleaner..
Conversely, a rotor 2 having a closed-off outlet
chamber 21 can advantageously be used as a compressor
or blower for a gaseous medium or as a pump for the
conveyance or for the pressure compensation of liquid
media.. A rotor 2 of this type can however also be used
to produce rotational speed if there is a difference in
pressure from a surrounding medium and to produce
energy if there are diffezences in the water or air
pressure.,
In the particular embodiment. of the invention shown in
Fig.. 6 of the drawings, a plurality of impellers 20 are
arranged axially next to one another and separated from
one another by separate outlet chambers 21.. In t.his
case, the four impellers 20 shown are arranged on a
common drive shaft. 9 which is mounted in two bearings 8
on a stator and the housing part.., All of the impellers
20 are surrounded by a multipart housing 7 which has
three iritermediate walls 22 and accordingly forms four
outlet. chambers 21 in each of which a similar impeller
20 is rotatably arranged..
Each impeller is in this case formed like the impeller
20 described with reference to Fig.. 1 to 5 of the
drawings and consists basically of nine airfoil
profiles 3 which are arranged on the outer lateral
surface 4 and between which passage openings 5 to the
inner cavity 6 are provided. In the first. impeller 20,
a first. inlet opening 10 to the outer region of the
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housing 7 is provided as a circular recess which
establishes a connection to the cavity 6 of the first
impeller 20 as an inlet chamber 12.. The gaseous oz
liquid medium provided is supplied to this first inlet.
opening 10, so the gaseous or liquid medium enters the
first inlet chamber 12, which is formed as the cavity
6, of the first impeller 20.. If the rotor 2 is driven
at a predetermined rotational speed, a pzessure
difference is produced on the airfoil profile 3 in the
region of the passage opening 5, as a result of which
the medium is drawn outward into the first outlet
chamber 21 suzzounding the impeller 20.. This gives rise
in this outlet chamber 21 to an inczease in pYessure
which acts through the second inlet. opening 27 in the
cavity or the inlet chamber of the second impeller 28..
This rotating second impeller 28 produces, again, a
pressure difference, so the medium enters a second
outlet chamber 29 with an increase in pressure.. As an
inlet opening to the third impeller is provided also in
the second outlet chamber 29, the pressure further
increases by the same amount in each of the subsequent
two outlet chambers, so a four-stage pump of this type
leads to a four times greater rise in pressure than in
a single-stage pump 1 compzising only one impeller 20,.
A multistage pump of this type as a rotary machine can
be equipped with a large number of pressure increase
stages, thus allowing almost any desired increases in
pressure to be established, depending ori the rot.ational
speed provided..
A mult.ist.age pump of this type as a rotary machine can
also be for.med with radial stagesõ Foz this purpose, a
plurality of impellers 20 having outer diameters of
different sizes are arranged coaxially in one another
and made to rotate by a common drive shaft 9, A rotary
machine of such coaxial construction allows not only
vezy high pressures to be produced but rather also, as
a result of the high effective surface area of the
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airfoil profiles, high flow volumes per unit of time to
be conveyed..
Fig.. 9 of the drawings shows a further particular type
of embodiment of the invention showing a drive turbine
preferably for a liquid medi.um.. Provided for this
purpose is a single-stage cylindrical rot.or 2 which has
airfoil profiles 3 arranged on its outer lateral
surface and passage openings 5 to its cavity which is
arranged in a cylindrical housing 7.. The housing 7
contains at its one axial end an inlet opening 10 and
at. its other axial end an outlet opening 11 which is
formed in the manner of a bottleneck. The rotor 2
arranged in the housing 7 is driven by means of its
inlet. opening 10 via a shaft. 9 by means of which the
preferably liquid medium, such as for example water, is
also supplied.. Rotation causes the water to be drawn
into the surrounding housing as an outlet chamber 21,
thus producing therein excess pressure which issues
from the flow-beneficial narrow bottleneck-type outlet
opening 11 into the surrounding medium. Depending on
the drive rotational speed and cross-sectional surface
area of the outlet opening 11, the water flows at a
specific outflow speed into the surrounding stagnant
water, thus producing a turbine-like recoil effect..
This allows preferably water vehicles to be driven or
liquids to issue at high pressure as a function of
direction into similar or different media..
