U.S. patent application number 14/241814 was filed with the patent office on 2014-09-04 for turbocompressor and use.
This patent application is currently assigned to KSB Aktiengesellschaft. The applicant listed for this patent is Markus Friedl, Dirk Ingmar Uhlenhaut, Urs Weilenmann. Invention is credited to Markus Friedl, Dirk Ingmar Uhlenhaut, Urs Weilenmann.
Application Number | 20140248141 14/241814 |
Document ID | / |
Family ID | 46845732 |
Filed Date | 2014-09-04 |
United States Patent
Application |
20140248141 |
Kind Code |
A1 |
Weilenmann; Urs ; et
al. |
September 4, 2014 |
Turbocompressor and Use
Abstract
A radial turbocompressor having at least two compressor stages
is provided. A motor is co-axially located on a shaft with radial
impellers of the compressor stages, and the motor and the
compressor stages are arranged in a common, vertically-split
housing. The medium to be compressed enters the housing through an
intake opening in the housing, flows past and/or through the motor,
and then is compressed in the compressor stages. The medium leaves
the housing through an discharge opening that is arranged
co-axially with the shaft, thereby minimizing axial forces in the
turbocompressor.
Inventors: |
Weilenmann; Urs;
(Herrliberg, CH) ; Friedl; Markus; (Zuerich,
CH) ; Uhlenhaut; Dirk Ingmar; (Zuerich, CH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Weilenmann; Urs
Friedl; Markus
Uhlenhaut; Dirk Ingmar |
Herrliberg
Zuerich
Zuerich |
|
CH
CH
CH |
|
|
Assignee: |
KSB Aktiengesellschaft
Frankenthal
DE
|
Family ID: |
46845732 |
Appl. No.: |
14/241814 |
Filed: |
August 28, 2012 |
PCT Filed: |
August 28, 2012 |
PCT NO: |
PCT/EP2012/066672 |
371 Date: |
February 27, 2014 |
Current U.S.
Class: |
415/206 |
Current CPC
Class: |
F04D 25/082 20130101;
F04D 29/584 20130101; F04D 29/5806 20130101; F04D 17/122 20130101;
F04D 25/06 20130101 |
Class at
Publication: |
415/206 |
International
Class: |
F04D 17/12 20060101
F04D017/12 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 30, 2011 |
DE |
10 2011 081 801.4 |
Aug 27, 2012 |
DE |
10 2012 016 844.6 |
Claims
1-9. (canceled)
10. A radial turbocompressor, comprising: at least two compressor
stages having radial impellers; a motor having a shaft on which the
radial impellers are arranged; and a common housing in which the
motor and the at least two compressor stages are arranged, the
housing including an intake opening configured to receive a medium
and a discharge opening arranged co-axially with the shaft; wherein
the housing, motor and at least two compressors stages are arranged
to split the medium entering the housing through the intake opening
into a first partial flow outside the motor and a second partial
flow through a gap between a rotor and a stator of the motor, and
reunite the first and second partial flows before the medium enters
the first compressor stage of the at least two compressor stages,
and wherein the medium is discharged from the housing through the
discharge opening.
11. The turbocompressor as claimed in claim 10, wherein in the
final compressor stage of the at least two compressor stages the
housing, motor and at least two compressors stages are arranged to
cause the medium first to flow through a radial impeller, then into
a diffuser and then into a return duct that is arranged to feed the
medium directly to the discharge opening.
12. The turbocompressor as claimed in claim 10, wherein the intake
opening is arranged co-axially with the shaft.
13. The turbocompressor as claimed in claim 10, wherein the shaft
on which the rotor of the motor and the radial impellers are
arranged is a common shaft.
14. The turbocompressor as claimed in claim 10, wherein radial
bearings and axial bearings are arranged on the shaft between the
motor and the radial impellers such that the medium flows through
the radial bearings and axial bearings.
15. The turbocompressor as claimed in claim 10, wherein at least
one of a surface of the shaft and a region between the motor and
the radial impellers includes an enhanced heat transfer
surface.
16. The turbocompressor as claimed in claim 15, wherein the
enhanced heat transfer surface is a surface having an increased
surface area.
17. The turbocompressor as claimed in claim 10, wherein the housing
is a vertically-split housing.
18. A heat pump comprising a turbocompressor as claimed in claim
10, wherein the medium is a heat transfer medium of the heat pump
and heat produced by the motor is supplied to the heat transfer
medium.
19. The heat pump as claimed in claim 18, wherein the heat transfer
medium is compressed after receiving heat from the motor.
Description
[0001] This application is a National Phase of PCT International
Application No. PCT/EP2012/066672, filed Aug. 28, 2012, which
claims priority under 35 U.S.C. .sctn.119 from German Patent
Application No. 10 2011 081 801.4, filed Aug. 30, 2011 and German
Patent Application 10 2012 016 844.6, filed Aug. 27, 2012, the
entire disclosures of which are herein expressly incorporated by
reference.
BACKGROUND AND SUMMARY OF THE INVENTION
[0002] The invention relates to a radial turbocompressor having at
least two compressor stages, wherein a motor drives radial
impellers of the compressor stages which are arranged on a shaft,
wherein the motor and the compressor stages are arranged in a
common housing and a medium enters the housing through an intake
opening, and wherein one part of the medium is guided through the
motor and another part flows past the motor, both parts are then
brought back together, are compressed and exit the housing through
a discharge opening.
[0003] Both blowers and compressors can be used for the delivery of
gases, the fundamental differences being in their construction and
field of application. In contrast to compressors, blowers are set
up for high flow rates and produce only a small increase in
pressure.
[0004] German patent document no. DE 60016886 T2 describes a blower
acting as an air pump and used for inflating air mattresses,
bicycle tires or sports balls. The air is delivered by impeller
wheels which are arranged in a housing made of hard plastic.
[0005] As their name suggests, compressors are set up for
compressing gases. During this process, and under appropriate
operating conditions, the gas can also enter a supercritical state.
The turbocompressor according to the invention is preferably used
for the delivery of carbon dioxide. During the compression step,
the carbon dioxide passes from a gaseous state to a supercritical
state as the critical temperature is only 31.0.degree. C. and
carbon dioxide has a relatively low critical pressure of just 73.8
bar. The carbon dioxide is sometimes already in a supercritical
state upon entry to the compressor. In order to encompass both
gases and supercritical fluids, reference is made in the context of
the invention to a medium which is compressed.
[0006] Compressors can operate either according to the displacement
principle or the dynamic principle. In the case of the displacement
principle, compression is achieved by enclosing a body of gas and
then reducing the space in which the gas is contained. Examples of
compressors operating according to the displacement principle are
reciprocating-piston compressors and rotary piston compressors.
[0007] By contrast, the present invention relates to compressors
operating according to the dynamic principle. In the case of the
dynamic principle, the gas is strongly accelerated in an impeller
and is compressed by deceleration in a downstream diffuser.
Compressors operating according to the dynamic principle are called
turbocompressors.
[0008] Turbocompressors fall into one of two main types: axial
turbocompressors and radial turbocompressors. In axial
turbocompressors, the gas flows through the compressor in a
direction parallel to the shaft.
[0009] The present invention relates to radial turbocompressors.
The gas flows axially into the impeller of the compressor stage and
is then accelerated, by centrifugal force, radially outward in the
impeller intermediate space which narrows in the manner of a
nozzle. The gas leaves the impeller intermediate spaces with great
speed at the impeller circumference and flows into the diffuser. In
the case of conventional radial turbocompressors, after the last
compressor stage, the gas flows away radially outward through a
pressure pipe oriented vertically with respect to the rotor
axis.
[0010] The compressor stages are driven by a motor. The electric
motor comprises a rotor and a stator. In the case of the present
invention, the rotor and the radial impellers are arranged on a
common shaft.
[0011] The prior art discloses embodiments in which the compressor
stages and the motor are in each case surrounded by an individual
housing, wherein the motor shaft leaves the motor housing and
enters the compressor stage housing.
[0012] By contrast, in the case of the present invention, the motor
and the compressor stages are arranged in a common housing. The gas
enters the housing through an intake opening. The uncompressed
medium first flows past the motor and is then compressed. After
passing through the compressor stages, the medium leaves the
housing through a discharge opening.
[0013] In the case of conventional radial turbocompressors, the
housing is often split horizontally. During assembly, the shaft
together with the impellers is placed in the lower half of the
housing. The upper half of the housing contains the intake pipe and
the pressure pipe, which are formed perpendicularly outward on the
upper half of the housing. The two halves are then brought
together. The medium is supplied and removed through the pipes
which project vertically outward with respect to the axis of
rotation of the shaft.
[0014] Turbocompressors often have to be integrated inside a
machine building. This often raises problems in terms of space,
owing to the arrangement of many other apparatus and machines. In
addition, largely vibration-free operation of the turbocompressor
has to be guaranteed in order that neither the machine itself nor
adjacent apparatus are damaged. To this end, costly mounting of the
rotor by means of axial and radial bearings is necessary. Costly
bearing constructions are necessary in order to compensate for the
axial force of the impellers.
[0015] Against this technical backdrop, the present turbocompressor
is constructed in such a manner that it has a compact and stable
construction and compensates for the axial force in a simple and
cost-effective manner by virtue of the fact that the discharge
opening is arranged centrally in the axial direction with respect
to the axis of rotation of the shaft.
[0016] In the final compressor stage, the medium first flows
through a radial impeller and is then guided into a diffuser. A
return duct feeds the medium to the axial discharge opening.
[0017] In contrast to conventional turbocompressors, the medium
leaves the housing not through a pressure pipe arranged radially
with respect to the shaft but through a discharge opening arranged
axially with respect to the axis of rotation of the shaft. The
housing is embodied as a compact pressure vessel whose cylindrical
casing does not have any disruptive pressure pipes but instead a
discharge opening on the end face of the pressure vessel. The
connection flanges employed in the case of the present invention
are very stable in comparison to pressure pipes which lead away
perpendicularly.
[0018] The axial arrangement of the discharge opening, centrally
with respect to the shaft, means that the outlet pressure of the
medium in the axial direction acts as a reaction force on the
outlet-side end of the shaft. This compensates for the axial
force.
[0019] Preferably, the intake opening of the turbocompressor is
also arranged centrally in the axial direction with respect to the
axis of rotation of the shaft. The housing, embodied as a
cylindrical pressure vessel, then has no pipes on the casing
surface. Both the supply and removal of the medium occur via the
end faces of the cylindrical pressure vessel. The end faces are
preferably formed as curved bases on the casing part of the
pressure vessel. The circular intake opening is introduced into the
center of one base. The circular discharge opening is introduced
into the center of the opposite base.
[0020] The described compressor very efficiently compresses the
medium which is guided through, although a considerable quantity of
heat can nonetheless be released in the motor. It is an object of
the invention to simply and cost-effectively remove the waste heat
generated.
[0021] The impellers of the turbocompressor are preferably driven
by an electric motor having a rotor and a stator. In an embodiment
of the compressor according to the invention, the medium is split
into two partial flows, wherein a first partial flow of the medium
is guided past between the stator of the motor and a static
component of the turbocompressor and a second partial flow is fed
through the motor, in particular between the rotor and stator of
the motor. The static component can be the housing itself or a
component connected to the housing. The medium which is guided past
takes up heat and thus serves to cool the motor. After passing the
motor region, the two partial flows are reunited and enter the
first compressor stage, in which the medium is compressed. In one
variation, the second partial flow can also be guided through the
stator of the motor. Corresponding ducts must be provided to this
end.
[0022] In an advantageous configuration of the invention, bearings,
in particular radial bearings and axial bearings, are arranged
between the motor and the impellers. The arrangement at this
location prevents excessive heating of the bearings as the medium
is not yet in a compressed state.
[0023] For further cooling of the device, it is proposed that the
surface be configured so as to favor a transfer of heat between the
individual components of the compressor and the medium. To that
end, the surface of the components is to be roughened so as to
increase the surface area while at the same time markedly
preventing the formation of eddies. If this transfer is carried out
at a point at which the medium is not yet compressed, the
temperature difference between the medium and the components is
very large, thus favoring the process.
[0024] The present invention is very advantageously employed for
use in a heat pump in which a heat transfer medium is pumped. The
heat produced by the motor is supplied to this heat transfer
medium, thus increasing an increase in the overall efficiency of
such an installation as practically no electrical power is lost.
The waste heat from the motor can be directly recovered upon
compression of the heat transfer medium.
[0025] In one advantageous configuration, CO2 is used as heat
transfer medium. This gas is chemically harmless and is available
at low cost almost everywhere. For use in a heat pump, it can be
employed in the critical region, where the physical properties can
be used to particularly good effect.
[0026] Other objects, advantages and novel features of the present
invention will become apparent from the following detailed
description of one or more preferred embodiments when considered in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 shows a turbocompressor in accordance with an
embodiment of the present invention in axial section,
[0028] FIG. 2 shows the guiding paths of the medium of FIG. 1 in
the turbocompressor,
[0029] FIG. 3 is a perspective representation of the compressor
stages of FIG. 1,
[0030] FIG. 4 shows the FIG. 3 compressor stages in axial
section,
[0031] FIG. 5 is a perspective cutaway representation of the
housing of the turbocompressor of FIG. 1,
[0032] FIG. 6a is a perspective view of a radial impeller in
accordance with an embodiment of the present invention, and
[0033] FIG. 6b is a perspective view of the FIG. 6A radial
impeller, represented without a cover disk.
DETAILED DESCRIPTION
[0034] FIG. 1 shows an axial section through an oil-free
turbocompressor which, in the exemplary embodiment, is designed for
the delivery of carbon dioxide. The guiding paths of the carbon
dioxide are represented in FIG. 2. In the following, both figures
are referred to in parallel, where the components are detailed in
FIG. 1 and FIG. 2 shows the guiding paths.
[0035] The carbon dioxide enters the housing 2 of the
turbocompressor through the intake opening 1. In the exemplary
embodiment, the carbon dioxide has at the intake opening 1 a
pressure of 38 bar and a temperature of 8.degree. C. The carbon
dioxide flow splits into two partial flows 3, 4.
[0036] The as-yet uncompressed carbon dioxide flows past the motor
5 of the turbocompressor. The motor 5 is embodied as an electric
motor. It is a two-pole permanent magnet machine rotating, at the
reference point, at 141,000 rpm. The motor 5 is arranged on the
low-pressure side of the compressor. It comprises a rotor 6 and a
stator 7. The active part of the rotor 6 consists of a cylindrical,
diametrically magnetized solid magnet. The magnet is encased on
account of its mechanical properties.
[0037] The stator 7 is made up of individual metal plates. The
grooves are insulated from copper windings by an insulating foil.
The motor 5 is cooled by the carbon dioxide flowing past.
[0038] A gap exists between the rotor 6 and the stator 7. The inner
partial flow 4 flows through this gap between the rotor 6 and the
stator 7. In order to reduce friction losses, a free-floating
axially mounted sleeve 8 can be inserted into the gap. The inner
partial flow 4 is guided through between the rotor 6 and the
floating sleeve 8 and between the sleeve 8 and the stator 7, and in
so doing removes heat. As the gaps between the sleeve 8 and the
rotor 6 and between the sleeve 8 and the stator 7 are very small, a
pressure loss arises which must be considered when designing the
turbocompressor.
[0039] The outer partial flow 4 is fed past between the stator 7
and a static component 9. The static component 9 is an inner
support structure. The outer partial flow 4 cools the stator 7. It
is fed along the winding heads and the laminated core. In order to
set the ratio between the two partial flows 3, 4, a throttle is
integrated into the path of the outer partial flow 4. A split of
97% outer partial flow 4 to 3% inner partial flow 3 has proven
particularly advantageous. A 3% proportion of the inner partial
flow allows the rotor 6 to be cooled to approx. 50.degree. C.
[0040] The stator 7 is attached to the inner support structure. The
inner support structure, for its part, is secured to the main
flange 10 of the housing 2.
[0041] The magnet of the rotor 6 is shrunk into a shaft 11. In
addition, three radial impellers 12 are secured on the shaft 11.
The shaft 11 is mounted with two radial gas bearings 13 and one
axial gas bearing 14. The turbocompressor is entirely oil-free.
[0042] Both partial flows 3, 4 are united before entering the first
compressor stage. The carbon dioxide is compressed in the three
compressor stages to a pressure of 90 bar and exits at the
discharge opening 19. According to the invention, the discharge
opening 19 is arranged centrally in the axial direction with
respect to the axis of rotation of the shaft 11. At the outlet, the
carbon dioxide is in a supercritical state.
[0043] FIG. 3 shows the three radial impellers 12 arranged one
behind another. The radial impellers 12 are arranged in parallel
next to one another on the shaft 11. In this case they are closed
radial impellers. The carbon dioxide enters inlet openings 15 of
the radial impellers 12 in the axial direction and exits in the
radial direction from the outlet openings 16. The carbon dioxide is
compressed from left to right as seen in the depiction and hence
always in the same axial direction.
[0044] FIG. 4 shows an axial section through the three compressor
stages. After the radial impeller 12, the carbon dioxide passes
into a diffuser 17 and then flows on into a return duct 18. Kinetic
energy is imparted to the carbon dioxide in the radial impellers 12
and is converted to pressure energy in the diffusers 17. The return
ducts 18 feed the carbon dioxide to the next compressor stage.
According to the invention, in the final compressor stage, the
carbon dioxide flows first through a radial impeller 12, then
through a diffuser 17 and then through a return duct 18 which feeds
the carbon dioxide directly to the discharge opening 19 which is
arranged centrally in the axial direction with respect to the axis
of rotation of the shaft 11.
[0045] FIG. 5 shows the housing 2 of the turbocompressor. The
housing 2 is embodied as a cylindrical pressure vessel. According
to the invention, the housing 2 is split vertically. It consists of
the main flange 10, an intake-side part 20 and a discharge-side
part 21. The discharge-side part 21 consists of a flange ring 22, a
tubular piece 23 and a torispherical head 24 which are welded
together to form one component. At the center of the torispherical
head 24 is a connection piece 25 which projects outward in the
axial direction and has a duct as discharge opening 19 for the
carbon dioxide.
[0046] The intake-side part 20 of the housing 2 has a torispherical
head 26. The intake opening 1 is introduced into the housing 2 at
the center of the torispherical head 26. The intake opening 1 and
the discharge opening 19 lie on an axis A A' which passes axially
through the center of the cylindrical housing 2.
[0047] The main flange 10 supports all the integrated elements and
provides space for leadthroughs such as the electrical supply or
temperature probe. The main flange 10 serves as a basic element for
the assembly as all integrated elements are secured to the main
flange 10.
[0048] FIGS. 6a and 6b show the construction of the radial
impellers 12. FIG. 6a shows the assembled state with cover disk 27.
The cover disk 27 is not shown in FIG. 6b in order to show the
inside of the radial impeller 12. The blades 28 of the radial
impeller 12 are formed on a support body 29. The cover disk 27 is
manufactured separately and is positioned on the support body 29
having its blades 28. The cover disk 27 is connected over the
entire surface to the upper edges of the blades 28 and therefore
rotates, when the turbocompressor is in operation, at the same
rotational speed as the support body 29 having its blades 28. The
radial impellers 12 are pushed onto the shaft 11 via the hub
30.
[0049] The foregoing disclosure has been set forth merely to
illustrate the invention and is not intended to be limiting. Since
modifications of the disclosed embodiments incorporating the spirit
and substance of the invention may occur to persons skilled in the
art, the invention should be construed to include everything within
the scope of the appended claims and equivalents thereof.
* * * * *