Title of Invention

ELECTRIC MOTOR HAVING A CO-AXIALLY ARRANGED PUMP FOR A COOLANT CIRCUIT

Abstract The invention relates to an electric motor (1) having a coaxially arranged pump (6) for a coolant circuit in particular, in a system with temperature transfer or heat transfer. Within housing parts (7, 10) which are configured as a hermetically sealed pressure enclosure, a shaft assembly (5) transmits a torque from the electric motor (1) to at least one impeller (8) which is arranged in the pump housing (7), and a flywheel (12) is arranged between the electric motor (1) and the pump housing (7). All the rotating parts are arranged within a hermetically sealed motor/pump assembly, and the motor/ pump assembly is filled with fluid. Here, the flywheel (12) comprises a flywheel body (13) having a multiplicity of cavities (14, 15) and having heavy-metal inserts (16, 17) which are arranged in the cavities. A heavy metal having a density of greater than 11.0 (kg/dm3) forms the heavy-metal inserts or is arranged therein, and the flywheel body (13) is composed of a high-strength material.
Full Text

KSB Aktiengesellschaft
Description.
Electric motor having a coaxially arranged pump
The invention relates to an electric motor having a
coaxially arranged pump for a coolant circuit, in
particular in a system with temperature transfer and/or
heat transfer, within housing parts, which are
configured as a hermetically sealed pressure enclosure,
a shaft assembly transmits a torque from the electric
motor to at least one impeller, which is arranged in
the pump housing, and a flywheel is arranged between
the electric motor and the pump housing, all the
rotating parts are arranged within a hermetically
sealed motor/pump assembly, and the motor/pump assembly
is filled with fluid.
In power station systems equipped with heat generators
and having temperature transfer and/or heat transfer
devices, it is known to use motor/pump assemblies,
which are equipped with a flywheel. This is a safety
measure in order to be able to guarantee that, in the
event of a possible fault, a coolant circulation is
maintained through the pump for a minimum time due to
the inertia of a flywheel. Due to the moment of inertia
of a flywheel, such an electric motor continues to run
even when the power has failed, and in doing so the
motor/pump assembly pumps a quantity of coolant.
Although reduced, such a quantity of coolant is
sufficient to guarantee a dissipation of heat in a heat
transfer device until the heat generator has been
safely switched off.
A so-called dry electric motor has been disclosed as a

result of US-A 3 960 034 in which the motor and the
flywheel are cooled with air. Here, the flywheel is
additionally equipped with a protective device in order
to prevent possible damage to the environment due to a
disintegrating flywheel in the event of overspeeds.
However, in the case of motor/pump assemblies without
shaft seals, disclosed by DE-C 2 807 876 or US-A 4 084
87 6, there is a hydrodynamic friction resistance due to
the motor filled with coolant and due to a flywheel
rotating in the coolant. The rotation of the flywheel
in the coolant, frequently water, causes a high power
loss due to the hydrodynamic friction and the
generation of heat energy. This reduces the overall
efficiency of pump, motor and flywheel. This motor/pump
assembly has a thermal barrier with a thin housing neck
between the pump section and the motor section in order
to keep the heat conduction between the hot pump
housing and the cooled motor housing as low as
possible. A flywheel driven by the shaft assembly is
located behind the thermal barrier on the face of the
motor housing and within a pressure-tight common
housing. Furthermore, to reduce the hydrodynamic
friction losses, the flywheel is surrounded by a
sleeve, which is rotatably mounted in the housing and
has inlet openings for the fluid in the motor housing.
In operation, the sleeve assumes an average speed,
which is less than the speed of the flywheel, due to
the hydrodynamic friction surfaces between housing,
sleeve and flywheel. This is intended to give rise to a
reduction in the friction losses at the flywheel, which
is arranged in the cooler motor section.
An electric motor in the form of a canned motor for a
motor/pump assembly with a flywheel is disclosed by EP
0 351 488 B1 or US-A 4 886 430. The flywheel is
designed as a bearing element within the housing part,
which forms a pressure enclosure, in the area of a

pressure-side pump housing cover of the encapsulated
and fluid-filled motor/pump assembly. It undertakes the
radial bearing function for the shaft assembly in the
area of the pump housing. Furthermore as the flywheel
is also designed as an axial bearing, in contrast to
the solution according to DE-C 2 807 876, this has
enabled an axial bearing arrangement at the end of the
motor remote from the pump to be dispensed with.
A pot-shaped insert is arranged in the housing between
the pump housing and the flywheel absorbing the bearing
forces as an integral thermal barrier. It is provided
with insulating air chambers on the outside and
opposite the pump section. An additional external fluid
cooling is arranged on its inside facing the flywheel
face. A further wall element absorbing the bearing
forces is arranged between the fluid cooling and the
face of the flywheel near the pump. Due to the design
of the canned motor/pump assembly, the flywheel chamber
and the rotor chamber of the electric motor are filled
with the pumping fluid to be pumped, and these chambers
are at the same pressure as the pump housing, while the
stator chamber of the motor is designed to be dry. The
motor is enclosed by a heat exchanger, through which
the same water flows that lubricates and cools the
bearing elements abutting the flywheel. This cooling
circulation from the motor, radial and axial bearing as
well as the flywheel also flows through the flywheel
itself. This therefore weakens the hub/shaft bonding of
the flywheel.
The invention is based on the problem of achieving an
improved solution for motor/pump assemblies equipped
with a flywheel, in which the design of a flywheel, its
operational safety and also its power loss as a result
of hydrodynamic friction are improved.
The solution to this problem provides that the flywheel

comprises a flywheel body having a multiplicity of
cavities and having heavy-metal inserts, which are
arranged in the cavities, that a heavy metal having a
density of greater than 11.0 (kg/dm3) forms the heavy-
metal inserts or is arranged therein, and that the
flywheel body is composed of a high-strength material.
This solution offers the advantage of easier and better
adaptability to different operating situations. By
simple selection and arrangement of the cavities,
different heavy-metal inserts can be inserted therein.
For those applications in which the pumping fluid in
the motor/pump assembly can undergo unfavorable
reactions with the heavy-metal inserts, means are
provided for shielding the heavy-metal inserts against
a surrounding fluid. These means can be arranged on the
flywheel body. Additionally or alternatively, the
inserts are provided with means for separating the
heavy-metal inserts from a surrounding fluid.
It has been shown to be particularly advantageous when
the heavy-metal inserts are designed in the form of a
cartridge and fixed in the flywheel body by means,
which are known in themselves. In this respect, the
inserts can be safely manufactured at an alternative
place and are therefore easy to transport and can also
be stored. Later, when the machining of a flywheel body
is complete, they can be inserted into said flywheel in
the simplest manner. The retention of the heavy-metal
inserts in the flywheel body can be carried out using
technical means, which are known in themselves. These
would be welded joints, screwed joints, soldering,
gluing, shrink or press joints and the like. The type
of joint is chosen depending on the particular
operating conditions.
It is also possible to design the heavy-metal inserts
in the form of filler material placed in the cavities

and to retain them there using means, which are known
in themselves. This would be a solution for those cases
in which the heavy metal is stocked as a pourable,
granular material or similar and is to be handled
accordingly.
According to another embodiment of the invention, it
has been shown to be advantageous when the flywheel
body does not have a hole for feeding through the shaft
assembly. With electric motors having very high drive
powers, such as are used in large power stations, very
large forces act on such a flywheel. Here, there is a
risk that unfavorable hub stresses occur in the area of
the transition between flywheel body and shaft assembly
starting from a through-hole for a shaft assembly. In
the extreme case, for example in overload operation,
this can lead to the flywheel body breaking. On the
other hand, it is more advantageous to join the
flywheel body to the shaft assembly by means of single
or multi-part flange joints. This considerably reduces
the risk of the flywheel body breaking. The spur gears,
which serve to transfer the torque and which form the
joining means between flywheel body and shaft assembly,
are also advantageous.
As the electric motor and the hermetically sealed
motor/pump assembly driven thereby are filled with
pumping fluid, there is the additional problem here
that a flywheel rotating in the fluid also generates a
high power loss due to the fluid friction. For economic
or safety reasons it can nevertheless be expedient to
deliberately leave such a power loss in the area of the
flywheel in order to achieve the hermetic sealing and
to be able to dispense with the use of shaft seals,
which are prone to failure.
For this purpose, it is provided that at least one heat
exchanger surrounding the outside diameter of the

flywheel is arranged within the pressure enclosure and
forms a radial wall surface of a flywheel chamber, that
a high-pressure zone of the pump chamber is connected
by means of one or more flow paths fed over the outside
of the heat exchanger to a side of the flywheel chamber
remote from the pump, that a ring gap between heat
exchanger and flywheel forms a first return flow path
between the flywheel chamber remote from the pump and
the flywheel chamber near the pump, and that a second
return flow path arranged in the area of the shaft
assembly connects the flywheel chamber near the pump to
the pump chamber.
With this solution, a defined high but nevertheless
operationally safe temperature is guaranteed in the
flywheel chamber. Here, the knowledge is based on the
fact that at higher fluid temperatures within the
flywheel chamber the power losses occurring here are
greatly reduced, as the density of the fluid and its
viscosity are reduced as a result of the effect of
temperature, and therefore the friction losses are
minimized. The arrangement of the heat exchanger on the
larger diameter around the flywheel results in a
particularly efficient cooling action. An improved
cooling action occurs when a pumping fluid taken from
the pump chamber flows away via the largest diameter of
the heat exchanger and enters the flywheel chamber on
the side remote from the pump.
The pumping fluid will flow back into the pump chamber
via the flow and return flow paths as a result of the
pressure gradient in the pump housing between a low
pressure at the impeller inlet and a high pressure
after the impeller, after a guide device or in a spiral
chamber. As there are no holes in the flywheel, the
cooled pumping fluid will flow back in the opposite
direction through the gap between the outside diameter
of the flywheel and the inside diameter of the

cylindrical heat exchanger. In doing so, it will
additionally and for a second time be subjected to the
cooling action of the heat exchanger and at the same
time absorbs the lost heat of the flywheel. The pumping
fluid leaves the flywheel chamber on the smaller
diameter in the area of the shaft assembly and at its
other side near the pump. It flows back into the main
pump stream through relief holes arranged in the
impeller. The pressure difference between the removal
opening and the inlet opening in the pump housing can
be sufficient for driving this internal fluid flow.
The cooling action can be improved in that several heat
exchangers surround the flywheel coaxially on the
larger diameter, and between these heat exchangers a
ring gap or several channels form the flow path to the
flywheel chamber remote from the pump. The heat
exchanger(s) is/are connected to an external cooling
water source and can be designed in the form of a
cylinder, for example.
In addition, a further embodiment of the invention
provides that at least one pumping device driven by the
shaft assembly is arranged in the second return flow
path. This makes it possible to increase the flow rate
of the cooling liquid flow. These can be known means in
the form of a small additional impeller, which is
provided with holes or blades, a fluid circulation
screw or other known devices.
According to other embodiments, a motor cover on the
pump side forms the wall of the flywheel chamber remote
from the pump, and a cooling device is arranged in the
motor cover. This cooling device can be designed as a
low-pressure cooling device or as a high-pressure
cooling device. It is also possible to design this
cooling device as part of a high-pressure motor cooling
system. In order to reduce mixing, a shaft seal is

arranged between motor chamber and flywheel in the area
of the shaft assembly. This can be designed as a
restrictor section, labyrinth seal or similar.
An exemplary embodiment of the invention is shown in
the drawings and is described in more detail below. In
the drawings
Fig. 1 shows a cross section through a
motor/pump assembly,
Fig. 2 shows a perspective view of a flywheel
body and heavy-metal inserts,
Fig. 3 & 4 show enlarged views of the flywheel
chamber, and
Fig. 5 shows a diagram of a temperature
distribution at the flywheel.
Fig. 1 shows a liquid-cooled motor 1 having a housing
2, which is designed as a pressure enclosure. The
inside of the motor 1 is filled with fluid, and a high-
pressure cooling system 3 is connected to the ends of
the motor in order to dissipate the electrical power
loss. A radial and an axial bearing are arranged at the
one end of the motor 4, the axial bearing at the same
time serving as a pumping device for the cooling water
circulating within the motor and through the cooler 3.
The driving force of the motor acts on a shaft assembly
5 and thus transmits a torque to a pump 6, which is
coaxially arranged with respect to the electric motor
1. An impeller 8 with downstream guide device 9 is
arranged within a pump housing 7, and the pump housing
7 is sealed by means of a cover element 10 and
connected to the housing 2 of the motor 1 by means of
tie rods 11. A flywheel 12, the moment of inertia of
which ensures a further rotational movement of the

shaft assembly 5 with the connected impeller 8 and
therefore a pumping capacity of the pump 6 in the event
of a power failure, is located within the cover element
10, which is here designed in several parts.
Those housing parts 2, 4, 7, 10 of pump and motor,
which define an inner chamber with respect to a
surrounding atmosphere, form a so-called pressure
enclosure. This is designed for a very high system
pressure, which prevails in a heat transfer system, in
which this motor/pump assembly is installed for
circulating a pumping fluid. As such an assembly is
designed for drive powers greater than 600 kW and
therefore has a disproportionate size, the
representation in Fig. 1 is only of a schematic type.
Details are shown in the following Figures 2 and 3 in
an enlarged view.
Fig. 2 shows a view of a flywheel 12 in perspective. It
consists of a flywheel body 13, which is shown in light
gray in Figure 2. The flywheel body 13 also has a
multiplicity of cavities 14, 15 shown in dark gray.
These cavities 14, 15 serve to accommodate heavy-metal
inserts 16, 17 with which the moment of inertia of a
fully assembled flywheel 12 is increased. The cavities
14, 15 have different diameters, as a result of which
it is guaranteed that the flywheel body 13, which is
made of a high-strength material, is resistant to the
centrifugal forces prevailing during an operation. Due
to the arrangement, size and number of the cavities 14,
15, a safe stress characteristic is guaranteed in the
flywheel body 13 under the effect of high temperatures.
An adequate reserve of strength is therefore ensured
even under critical operating conditions, for example
in the event of turbine operation caused by an
operational fault or overload operation of the pump, as
a result of which the speed is higher than the rated
speed.

A flange joint 19, with which the connection to the
shaft assembly 5 is made, is fixed to the face 18 of
the cylindrical flywheel body 13. The spur gear 20
shown here acts together with an appropriate design of
the shaft assembly 5 to thus guarantee a reliable
transmission of torque. Other frictional and/or
interlocking forms of connection can also be used. In
doing so, however, it should be ensured that these
types of connection do not have a negative effect on
the stress characteristic within the flywheel body 13.
Furthermore, it can be seen from Fig. 2 that
correspondingly sized heavy-metal inserts 16, 17 are
arranged in the different sized cavities 14, 15. Here,
the heavy metal can be arranged as inserts in the form
of rods or filler material. The heavy-metal inserts 16,
17 shown here illustrate a variant in which the heavy
metal is to be found within a cartridge 21, 22. Such a
cartridge is simple to manufacture, easy to handle, to
store and to transport, and thus fulfils the
requirement for trouble-free stocking of such heavy-
metal inserts 16, 17. In addition, such a cartridge 21,
22 protects a heavy metal arranged therein against the
effect of the fluid, which surrounds a flywheel 12 for
cooling purposes, or vice versa.
The sealing of such a cartridge, which in this case is
designed in the form of a cylinder, is carried out by
means of known techniques, and is possible on normal
machine tools. Special machines are not required for
this. Such a cartridge 21, 22 can be retained within
the flywheel body 13 with the known techniques. It is
also possible to design the cavities 14, 15 in the
flywheel body 13 as through-holes or blind holes and to
arrange a heavy metal directly therein. In order to
secure the position of a heavy metal, which is located
directly in the cavities 14, 15, the cavities can be

sealed by means of individual cover elements or by one
large cover element, the size of which corresponds to
the diameter of the flywheel.
Fig. 3 and 4 show an enlarged view of the arrangement
of the flywheel in the shaft assembly and its position
between pump and motor. The impeller 8 with a
downstream guide device 9 can be seen within the pump
housing 6. A single or multi-stage design can be used
depending on the type of pump. In the single or last
pump stage shown here, a removal pipe can be seen in a
zone with the highest pressure within the pump housing
7 - here after the guide device 9. This is used as flow
path 23 for a pumping fluid and guides this within the
pressure enclosure into the flywheel chamber 24. A pump
cover 10 and a motor cover 25 near the pump form the
flywheel chamber 24. The pressure and fluid-tight
contact surface 26 of the two cover parts 10, 2 5 lies
in the area of a face 18 of the flywheel 12 remote from
the pump. The two-part flywheel housing so formed makes
manufacture and assembly easier. All parts are held
together by tie rods 11, which are screwed into the
pump housing 7 and find their counter support in a
flange of the motor housing 2.
A heat exchanger 27, which surrounds the flywheel 12
and which is connected to a low-pressure cooling system
A-B which penetrates the pressure enclosure, is
arranged within the flywheel chamber 24. The flow path
23 connecting the pump inner chamber to the flywheel
chamber 24 carries a pumping fluid over the outside 28
of the heat exchanger 27 to the side of the flywheel
chamber 24 remote from the pump. A further low-pressure
cooling system C-D is arranged at the face of the
flywheel chamber 24 remote from the pump in the area of
the motor cover 25, with the help of which an
appropriate temperature gradient is achieved in the
area of the face 18 of the flywheel remote from the

pump. Furthermore, it can be seen that the motor cover
25 has a connector for a high-pressure motor cooling
system E, which is connected to the motor cooler 3. The
arrows show the direction of flow of the motor cooling
fluid around the stator end windings. At the same time,
they serve as lubricating fluid for the motor bearing
3 0 near the pump. The heated motor cooling fluid is
removed via channels 31 in the motor cover 25 and
cooled down by means of the motor cooler 3 shown in
Fig. 1 and fed into the motor 1 once more at the motor
cover 4 remote from the pump.
Pumping fluid entering the flywheel chamber 24 at its
end remote from the pump flows through a ring gap 32
between the inside 33 of the heat exchanger 27 and the
outside diameter of the flywheel 12 to the flywheel
chamber 24.1 near the pump. This ring gap 32 forms a
first return flow path for the pumping fluid, which is
simultaneously subjected here to the effect of the heat
exchanger 27. It flows via the flywheel chamber 24.1
near the pump to the face 34 of the flywheel 12 near
the pump towards the shaft assembly 5. From the area of
the shaft assembly 5, it flows back via the second
return flow path arranged there to the impeller 8 of
the pump 6. In doing so, a pump bearing 35 is
lubricated at the same time. The direction of flow is
determined by the pressure gradient between the high-
pressure zone in the pump housing 7 and the lower-
pressure zone in the area of the impeller 8, which is
defined by the axial thrust relief openings 36.
When designing such a motor/pump assembly, the size and
number of flow paths is determined for the specified
operating conditions in order to achieve a basic
setting for the cooling pumping fluid for the
appropriate powers. It is also possible to provide an
additional pumping device 37 in the area of the second
flow path, which is driven by the shaft assembly 5. In

this exemplary embodiment, a fluid circulation screw is
shown, but it could equally well be an appropriate
impeller or other known auxiliary pumping device 37.
This can improve the cooling performance of the pumping
fluid circulating in the flywheel chamber 24, 24.1. The
lost heat produced by the flywheel 12 due to the
hydrodynamic friction in the fluid is thus dissipated
in an extremely effective manner by mass transport.
Due to the specific guidance of the internal cooling
flow from the pump chamber to the flywheel chamber 24,
24.1, the temperature level in the flywheel chamber and
also within the flywheel 12 can be influenced such that
a homogenous temperature level develops during
operation. The development of the homogenous
temperature level in the flywheel 12 is assisted by the
heat exchanger performance at the outer circumference
of the flywheel 12 and the cooling action at the face
18 of the flywheel remote from the pump. Controlling
this heat exchanger performance enables the homogeneity
of the temperature level to be maintained. This has the
decisive advantage that material stresses caused by
temperature differences are prevented within the
flywheel 12.
With this solution, heat can even be fed back into the
pump circuit for that operating condition in which the
temperature level in the flywheel chamber is higher
than the temperature level of the pumping fluid. By
this means, it is possible to partially recover the
lost heat. In any case, however, the temperature in the
flywheel chamber 24, 24.1 is limited to a maximum,
which does not have a negative effect on the strength
of the flywheel body.
Fig. 4 shows a variant of Fig. 3 in which only the
lower-pressure cooling system C-D in the area of the
face 8 of the flywheel 12 remote from the pump has been

dispensed with. Instead of this, the high-pressure
motor cooling system E is used simultaneously to also
affect the temperature level in the flywheel chamber
24. Depending on the specified operating conditions of
such a motor/pump assembly, the necessary homogenous
temperature level in the flywheel 12 is also ensured
with this solution. The wall 29 of the flywheel chamber
24 remote from the pump, formed by the pump-side motor
cover 25, is here subjected to the high-pressure motor
cooling system E with the help of a connection 39. A
shaft seal 38, which reduces mixing of the fluids, is
arranged in the area of the wall 25.
A first locus σA, which shows a determining strength
characteristic of the material of the flywheel body as
a function of temperature, is illustrated in the
diagram of Fig. 5. This strength characteristic, for
example 80% of the elastic limit, includes an adequate
safety margin with respect to material failure.
The overall efficiency of the motor/pump assembly is
plotted against temperature in a second locus nges. The
temperature corresponds to that, which can prevail in
the flywheel chamber. The point of intersection A of
the two loci corresponds to the operating point of the
motor/pump assembly with all cooling systems operating.
The optimum operating temperature Topt prevails at this
point A. Here, a homogenous temperature level Topt is
established in the flywheel chamber and in the
flywheel.
In addition, this operating point A has a further high
safety margin S compared with those operating
conditions in which a failure of an external cooling
system was expected. If such a condition occurs in
which one or more external cooling systems fail, which
constitutes a fault situation, then because of the
internal fluid friction within the flywheel chamber the

temperature will rise and establish itself at a maximum
temperature T0.
The consequence of such a temperature rise is that the
viscosity of the pumping fluid reduces as a result of
the increasing temperature, and therefore the power
loss in the flywheel chamber decreases. As a result of
this, the overall efficiency nges of the motor/pump
assembly increases. The negative effect of a
temperature rise, however, is a reduction in the
material strength of the flywheel body to a lower value
aL at the temperature T0. This gives rise to a fault
situation operating point B in the flywheel chamber at
the higher temperature level T0 in the event of a
failure of an external cooling. The strength of the
flywheel body is still guaranteed at this operating
point B, however, due to the remaining 20% elastic
limit reserve in this example. The shaded area C on the
right in the diagram adjacent to the fault situation
operating point B denotes an inadmissible operating
range.
As a result of deliberately forgoing an improvement in
the overall efficiency nes, a significant improvement
in the operational safety is achieved. Safe operation
of the motor/pump assembly is still guaranteed even in
the event of a failure of an external cooling device.
Even then, there is no fear that the flywheel will fail
due to inadmissible stress conditions in the material
of the flywheel body. Consequently, this enables
elaborate protection devices for the flywheel to be
dispensed with, which leads to a significant cost
reduction and an increase in the operational safety of
such a motor/pump assembly.

CLAIMS
1. An electric motor (1) having a coaxially arranged pump (6) for a coolant
circuit, in particular in a system with temperature transfer and / or heat transfer,
wherein within housing parts (7, 10), which are configured as a hermetically
sealed pressure enclosure, a shaft assembly (5) transmits a torque from the
electric motor (1) to at least one impeller (8), which is arranged in the pump
housing (7), and a flywheel (12) is arranged between the electric motor (1) and
the pump housing (7), all the rotating parts are arranged within a hermetically
sealed motor/ pump assembly, and the motor / pump assembly is filled with
fluid, characterized in that the flywheel (12) comprises a flywheel body (13)
having a multiplicity of cavities (14, 15) and having heavy-metal inserts (16, 17),
which are arranged in the cavities (14, 15), that a heavy metal having a density
of greater than 11.0 (kg/ dm3) forms the heavy-metal inserts (16, 17) or is
arranged therein, and that the flywheel body (13) is composed of a high-strength
material.
2. The electric motor as claimed in claim 1, wherein the means are arranged for
shielding the heavy-metal inserts (16,17) against a surrounding fluid.

3. The electric motor as claimed in claim 1 or 2, wherein the heavy-metal inserts
(16, 17) are designed in the form of a cartridge (21, 22) and fixed in the flywheel
body (13) by means, which are known in themselves.
4. The electric motor as claimed in claim 1 or 2, wherein the heavy-metal inserts
(16, 17) are designed in the form of filler material placed in the cavities (14, 15)
and are retained in the flywheel body (13) using means, which are known in
themselves.
5. The electric motor as claimed in one of claims 1 to 4, wherein the flywheel
body (13) does not have a hole for feeding through the shaft assembly (5).

6. The electric motor as claimed in one of claims 1 to 5, wherein the flywheel
body (13) is joined to the shaft assembly (5) by means of single or multi-part
flange joints (19, 20).
7. The electric motor as claimed in one of claims 1 to 6, wherein spur gears
(20) from the joining means between flywheel body (13) and shaft assembly (5).

8. The electric motor as claimed in the pre-characterizing clause of claim 1,
characterized in that at least one cylindrical heat exchanger (27) surrounding the
outside diameter of the flywheel (12) is arranged within the pressure
enclosure and forms a radial wall surface of a flywheel chamber (24), that a
high-pressure zone of the pump chamber is connected by means of one or more
flow paths (23) fed over the outside of the exchanger (27) to a side of the
flywheel chamber (24) remote from the pump, that a ring gap (32) between heat
exchanger (27) and flywheel (12) forms a first return flow path between the
flywheel chamber remote from the pump and the flywheel chamber (24. 1) near
the pump, and that a second return flow path arranged in the area of the shaft
assembly (5) connects the flywheel chamber (24.1) near the pump to the pump
chamber.
9. The electric motor as claimed in claim 8, wherein several cylindrical heat
exchangers (27) surround the flywheel (12) coaxially, and between the heat
exchangers (27) a ring gap or several channels from the flow path to the
flywheel chamber (24) remote from the pump.

10. The electric motor as claimed in claim 8 or 9, wherein at least one pumping
device (37) is arranged in the second return flow path, which pumping device is
driven by the shaft assembly (5).
11. The electric motor as claimed in one of claims 1 to 10, wherein the
cylindrical heat exchanger (27) is connected to an external cooling water source
(A-B).
12. The electric motor as claimed in one of claims 1 to 11, wherein a motor
cover (25) on the pump side forms the wall (29) of the flywheel chamber (24)
remote from the pump, and that a cooling device (C-D, F) is arranged in the
motor cover (25).

13. The electric motor as claimed in claim 12, wherein the cooling device (C-D)
is designed as a low-pressure cooling device.
14. The electric motor as claimed in claim 12, wherein the cooling device (E) is
designed as a high-pressure cooling device.

15. The electric motor as claimed in one of claims 11 to 14, wherein the cooling
device is designed as part of a high-pressure motor cooling system.
16. The electric motor as claimed in one of claims 1 to 15, wherein a shaft
seal is arranged between motor chamber and flywheel in the area of the shaft
assembly.



ABSTRACT


ELECTRIC MOTOR HAVING A CO-AXIALLY ARRANGED PUMP FOR A
COOLANT CIRCUIT
The invention relates to an electric motor (1) having a coaxially arranged pump
(6) for a coolant circuit in particular, in a system with temperature transfer or
heat transfer. Within housing parts (7, 10) which are configured as a
hermetically sealed pressure enclosure, a shaft assembly (5) transmits a torque
from the electric motor (1) to at least one impeller (8) which is arranged in the
pump housing (7), and a flywheel (12) is arranged between the electric motor
(1) and the pump housing (7). All the rotating parts are arranged within a
hermetically sealed motor/pump assembly, and the motor/ pump assembly is
filled with fluid. Here, the flywheel (12) comprises a flywheel body (13) having a
multiplicity of cavities (14, 15) and having heavy-metal inserts (16, 17) which are
arranged in the cavities. A heavy metal having a density of greater than 11.0
(kg/dm3) forms the heavy-metal inserts or is arranged therein, and the flywheel
body (13) is composed of a high-strength material.

Documents:

00221-kolnp-2008-abstract.pdf

00221-kolnp-2008-claims.pdf

00221-kolnp-2008-correspondence others.pdf

00221-kolnp-2008-description complete.pdf

00221-kolnp-2008-drawings.pdf

00221-kolnp-2008-form 1.pdf

00221-kolnp-2008-form 2.pdf

00221-kolnp-2008-form 3.pdf

00221-kolnp-2008-form 5.pdf

00221-kolnp-2008-international publication.pdf

00221-kolnp-2008-international search report.pdf

00221-kolnp-2008-pct priority document notification.pdf

221-KOLNP-2008-(13-12-2012)-ABSTRACT.pdf

221-KOLNP-2008-(13-12-2012)-AMANDED PAGES OF SPECIFICATION.pdf

221-KOLNP-2008-(13-12-2012)-ANNEXURE TO FORM 3.pdf

221-KOLNP-2008-(13-12-2012)-CLAIMS.pdf

221-KOLNP-2008-(13-12-2012)-CORRESPONDENCE.pdf

221-KOLNP-2008-(13-12-2012)-DESCRIPTION (COMPLETE).pdf

221-KOLNP-2008-(13-12-2012)-DRAWINGS.pdf

221-KOLNP-2008-(13-12-2012)-FORM-1.pdf

221-KOLNP-2008-(13-12-2012)-FORM-2.pdf

221-KOLNP-2008-(13-12-2012)-FORM-5.pdf

221-KOLNP-2008-(13-12-2012)-OTHERS.pdf

221-KOLNP-2008-CANCELLED PAGES.pdf

221-KOLNP-2008-CORRESPONDENCE OTHERS 1.1.pdf

221-KOLNP-2008-CORRESPONDENCE OTHERS 1.2.pdf

221-KOLNP-2008-CORRESPONDENCE-1.1.pdf

221-KOLNP-2008-CORRESPONDENCE-1.2.pdf

221-KOLNP-2008-CORRESPONDENCE-1.3.pdf

221-KOLNP-2008-EXAMINATION REPORT.pdf

221-KOLNP-2008-FORM 18-1.1.pdf

221-kolnp-2008-form 18.pdf

221-KOLNP-2008-FORM 26-1.1.pdf

221-KOLNP-2008-FORM 26.pdf

221-KOLNP-2008-GRANTED-ABSTRACT.pdf

221-KOLNP-2008-GRANTED-CLAIMS.pdf

221-KOLNP-2008-GRANTED-DESCRIPTION (COMPLETE).pdf

221-KOLNP-2008-GRANTED-DRAWINGS.pdf

221-KOLNP-2008-GRANTED-FORM 1.pdf

221-KOLNP-2008-GRANTED-FORM 2.pdf

221-KOLNP-2008-GRANTED-FORM 3.pdf

221-KOLNP-2008-GRANTED-FORM 5.pdf

221-KOLNP-2008-GRANTED-SPECIFICATION-COMPLETE.pdf

221-KOLNP-2008-INTERNATIONAL PRELIMINARY REPORT.pdf

221-KOLNP-2008-INTERNATIONAL PUBLICATION.pdf

221-KOLNP-2008-INTERNATIONAL SEARCH AUTHORITY REPORT 1.1.pdf

221-KOLNP-2008-INTERNATIONAL SEARCH REPORT & OTHERS.pdf

221-KOLNP-2008-OTHERS-1.1.pdf

221-KOLNP-2008-OTHERS.pdf

221-KOLNP-2008-PCT REQUEST.pdf

221-KOLNP-2008-REPLY TO EXAMINATION REPORT.pdf

221-KOLNP-2008-TRANSLATED COPY OF PRIORITY DOCUMENT.pdf

abstract-00221-kolnp-2008.jpg


Patent Number 257858
Indian Patent Application Number 221/KOLNP/2008
PG Journal Number 46/2013
Publication Date 15-Nov-2013
Grant Date 12-Nov-2013
Date of Filing 16-Jan-2008
Name of Patentee KSB AKTIENGESELLSCHAFT
Applicant Address JOHANN-KLEIN-STRASSE 9 67227 FRANKENTHAL
Inventors:
# Inventor's Name Inventor's Address
1 BRECHT, BERNHARD ROTKREUZSTRASSE 21, 67433 NEUSTADT/WEINSTRASSE
2 BRUHNS, UWE BUCHENWEG 8, 67574 OSTHOFEN
3 HARTMANN, HARALD AM KINDERBACH 29, 67271 KINDENHEIM
4 GRABER, RALF WALLONENSTRASSE 35, 67227 FRANKENTHAL
PCT International Classification Number F04D 29/04
PCT International Application Number PCT/EP2006/006644
PCT International Filing date 2006-07-07
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 10 2005 036 347.4 2005-07-29 Germany