Patent Application
20130039785
The present application claims the benefit of priority of German Application No.102011075097.5, filed May 2, 2011. The entire text of the priority application is incorporated herein by reference in its entirety.
The present disclosure relates to a device for moving a fluid, comprising a moving part to put the fluid into motion, and a synchronous motor, whereby the moving part can be driven directly by the synchronous motor and acts as its rotor.
Devices for moving fluids, particularly liquids, are normally used in the beverage industry. Here, a device of this nature may be a pump, a stirrer or similar device.
DE 35 01 127 A1 illustrates a device for producing mixed beverages, in which one or a plurality of dosing pumps are driven via a gear train by an electric motor. In this case the motor is located outside of the pumps. A pump of this nature is therefore operated externally, whereby however the problem arises, that a drive shaft extends from the motor through the pump housing to a rotor disc, impeller or similar device. Thus, the use of axial face seals is necessary to seal the pump housing with respect to the motor.
The following documents illustrate similar pumps in which in each case the drive shaft passes through the pump housing. In particular, DE 43 15 234 A1 illustrates a multi-stage centrifugal pump for mixing various beverage components, DE 100 52 797 A1 illustrates a pump driven by an electric motor, DE 195 05 543 A1 illustrates a centrifugal pump with a revolutions sensor and EP 0 355 796 B1 illustrates a centrifugal pump with a magnetically supported shaft.
DE 41 02 707 A1 also illustrates an embodiment of a turbo-pump with a magnetically supported impeller wheel. Outside of the pump housing there are a number of stator windings which produce a rotating magnetic field, which drives the impeller wheel by permanent magnets fitted to it, by switching on and off according to the determined position of a non-contacting control collector or commutator connected to each stator winding. Although a pump of this nature needs no axial facial seals, the generation of the rotating magnetic field is however complicated.
DE 39 42 679 A1 illustrates amongst other features an embodiment of a mixing device, which comprises a stirring mechanism driven by an asynchronous linear motor. The secondary part of the motor is here permanently connected to the steering mechanism. A mixing device of this nature does not need axial facial seals when the secondary part is located in the housing and partially encloses the stirring mechanism. Since however an asynchronous motor is used here, the induction currents in the secondary part must be able to flow such that a magnetic field can be established, whereby severe restrictions on its shape are necessary. Since the secondary part partially encloses the stirring mechanism, undesired turbulences may also form, which have a negative effect on the efficiency of the device.
Therefore, one aspect of the present disclosure is to provide a device for moving fluids which facilitates greater flexibility in the designed shape of the moving part.
The disclosure provides a device for moving a fluid, comprising a moving part to move the fluid, and a synchronous motor, whereby the synchronous motor comprises a stator with at least one stator coil and a rotor (or armature) with at least one rotor magnet, whereby the moving part can be driven directly by the synchronous motor and acts as its rotor.
The moving part can be driven directly, that is without a gear train, by the synchronous motor. Since the moving part acts as the rotor (or armature) of the motor, a drive shaft from the motor through a housing of the device to the moving part is not needed. A synchronous motor is an alternating current motor in which the rotor has a permanent magnetic field. In contrast to an asynchronous motor, where the rotor magnetic field is generated through induction, here induction currents do not need to be considered. This facilitates greater freedom in the designed shape of the moving part.
In this respect a fluid may be a liquid, in particular a beverage or a beverage component, a cleaning medium or a gas, in particular carbon dioxide. The term “movement” in this respect may be a general putting into motion and/or keeping in motion of a fluid, in particular pumping, conveying, blending, mixing and/or stirring.
The moving part can comprise one or a plurality of moving elements, such as vanes, blades, paddles or similar elements, for the transfer of kinetic energy to the fluid. The moving part can be supported on a shaft, axle or similar part. For this purpose the moving part can comprise a hub.
At least one rotor magnet can be arranged in and/or on the moving part and/or the moving part itself can consist of permanently magnetic material and/or the moving part can be covered completely or partially with permanently magnetic material.
The rotor magnets can in each case be permanent magnets or electromagnets. In particular the majority of the rotor magnets can either be permanent magnets or electromagnets. In one embodiment all the rotor magnets can be permanent magnets. The synchronous motor is then permanently excited.
The rotor magnets can be embedded beneath the surface of the moving part. The surface of the moving part may be of any desired material, for example stainless steel. In particular, the material can comprise a material different from that of the rotor magnets. The material, from which the moving part is produced, can also comprise stainless steel.
The device can comprise a housing, which at least partially encloses the moving part. At least one stator coil can be arranged in or on the housing and/or can be arranged outside of the housing and spaced from it.
The housing can partially or completely comprise an approximately cylindrical shape. In particular the housing can comprise a pipe segment or pot. In the approximately cylindrical part of the housing the moving part can move rotationally or linearly within it.
The stator coils can be arranged in and/or on the housing such that the stator magnetic field is coupled to the rotor magnets on and/or in the moving part such that the moving part is put into motion by the alternating stator magnetic field. The housing can be closed with respect to the stator. The moving part can be supported in the housing in diverse ways, for example by a ball bearing on an axle or internal shaft, which for example is joined to the housing.
The stator can also be spaced from the housing and in particular not mounted on the housing or not joined to it. The stator can also be mobile.
The stator coils can be fitted on the outside of the housing or embedded in the housing such that the inner surfaces of the housing comprise any desired material, for example stainless steel. The material, from which the housing is produced, can comprise, for example, stainless steel. The housing can also have pegs arranged on the outer side around which the stator coils are wound.
The moving part can at least partially enclose the stator of the synchronous motor. In particular the stator can then be located in the housing.
The moving part can comprise a ring-shaped or pot-shaped part, which at least partially encloses the stator. This ring-shaped or pot-shaped part can be a hub. On the outer sides of the ring-shaped or pot-shaped part moving elements for moving the fluid can be located, which can rotate around the stator.
The synchronous motor can be driven by single or polyphase alternating current. When using single-phase alternating current, a corresponding machine for the generation of polyphase alternating current can be omitted. When using polyphase alternating current, in particular three-phase alternating current (rotary current), a higher efficiency can be achieved.
The at least one stator coil can comprise a number of separate windings, which corresponds to the number of phases of the alternating current. With single-phase alternating current this can be one winding. With rotary current this can be three separate windings, which for example are wound in alternating sequence. The windings can also be encapsulated.
An approximately cylindrical part of the housing can be wound with a corresponding number of windings so that the moving part moves in the stator coil. Alternatively, then one or a plurality of travelling-field windings are possible as stator coils.
The synchronous motor can be a rotary motor or a linear motor. In this way when using a rotary motor the device can be a rotary pump and with the use of a linear motor a linear pump.
The synchronous motor can be operated in two directions. In this way the conveying direction, say in a pipe, can be easily reversed. The fluid can then be retarded.
The device can comprise a plurality of stator coils, whereby a rotor magnet describes a rotational path during the operation of the device, a plurality of stator coils are arranged essentially in the same plane as the rotational path, and in particular are arranged on a path concentric to the rotational path.
The designation “essentially” signifies that the configuration does not need to be geometrically perfect. Thus, for example, deviations may arise due to the constructional consistency of the housing or other constituent parts.
If the stator coils are also arranged in and/or on the housing, that is as close as possible to the rotational path of one or a plurality of rotor magnets, then a maximum coupling of the rotor magnets to the magnetic field of the stator can be achieved through this configuration. In this way the moving part can produce a high torque.
The stator coils can be essentially annular, in particular arranged around the moving part on a circular path concentric to the rotational axis of the moving part. It is conceivable that also a plurality of stator rings of this nature, i.e. stator coils arranged essentially in a ring shape, are provided along the rotational axis of the moving part. Also a plurality of stator rings in a plane are conceivable, which are in each case concentric to one another and can have diverse radii. It may be advantageous if each stator ring has the least possible distance to at least one of the rotational paths of the rotor magnets.
The stator coil configuration can be adapted to the shape of the housing. The stator coils can essentially be arranged on an elliptical path or along a polygon. This is advantageous if the housing has, for example, an elliptical or polygonal cross section.
The moving part can take the form of a rotor disc, an impeller, an impeller wheel, a pot, a piston, a rotary piston, a screw, a helical shaft or an agitator blade.
A moving element of the moving part can take the form of a vane, blade, paddle or similar part. In the case of a rotor disc or impeller wheel or impeller the pipe-shaped or ring-shaped outer housing can be omitted.
The device can be a centrifugal pump, screw pump, eccentric pump or rotary piston pump, a single or double-acting reciprocating pump or a stirrer.
In the case of a centrifugal pump the moving part can in particular have the form of a rotor disc, impeller wheel or impeller. Here, impeller wheels can, in particular, have the form of closed impeller wheels, i.e. impeller wheels with support and cover discs, semi-open impeller wheels, i.e. impeller wheels with a support disc, but without a cover disc, and open impeller wheels, i.e. impeller wheels without support and cover discs. The housing can be formed such that the centrifugal pump is a radial or semi-axial pump. Other types of centrifugal pump are also conceivable.
In the case of a positive-displacement pump the moving part can in particular have the form of a rotary piston, screw or helical shaft. Other forms of positive-displacement pumps can also be implemented.
In the case of a reciprocating pump the moving part can in particular have the form of a piston. Here, the device can be connected to one or a plurality of flow chambers.
In the case of a stirrer the moving part can comprise one or a plurality of agitator blades. The housing can partially or completely comprise an approximately cylindrical shape. In particular the housing can comprise a pot with a flat or rounded bottom.
With regard to an imaginary radial line from the axis of rotation to a point on the moving part the furthest away from the axis of rotation, at least one rotor magnet can be spaced half as far from the axis of rotation as the said point. Here, one, a plurality or all of the rotor magnets can have this spacing. Also a spacing of at least 60%, 70%, 80% or 90% of the distance to this point is conceivable. The rotor magnets can in particular be arranged on and/or in the moving elements of the moving part.
Alternatively, one, a plurality or all of the rotor magnets can also be arranged as close as possible to the axis of rotation of the moving part. This can be advantageous if the moving part partially encloses the stator. In particular, the rotor magnets can also be arranged in and/or on the hub of the moving part. This can also be advantageous if, for example, it would be too elaborate to arrange the rotor magnets in the moving elements, because they are too thin and fitting the rotor magnets to the surface of the moving elements is not desired.
The device can comprise at least two rotor magnets, which are arranged with adjacent opposite poles in and/or on the moving part. The device can comprise more than two rotor magnets, which are arranged in and/or on the moving part in a sequence such that adjacent rotor magnets in each case have opposite poles.
This configuration can in particular be used for a reciprocating pump, which can be driven by a linear motor. Here, a number of the adjacently arranged magnets, having in each case opposite poles, can be located in and/or on the piston-shaped moving part. This piston can, for example, be located in a partially or completely approximately cylindrical housing. The housing can be wound over a certain length with single-phase or polyphase windings or comprise one or a plurality of travelling-field windings, so that the piston can be moved along the housing by a linear motor.
The device can comprise a frequency converter for controlling the synchronous motor. The synchronous motor can be precisely controlled by a frequency converter.
Further advantages and features of the disclosure are explained in the following based on the exemplary figures. The following are schematically illustrated:
a-1c centrifugal pumps with internally situated moving part;
a-2c centrifugal pumps with internally situated stator;
a-3f diverse feed pumps and positive-displacement pumps;
a-4d a reciprocating pump with linear drive;
a-5d several variants of stirrers.
a shows a perspective cutaway view of a centrifugal pump 100 with the housing 101 and internally located moving part 102, which is surrounded by a stator, whereby here the entirety of the stator coils 103 is regarded as the stator. During the operation of the pump 100 the fluid is drawn through an inlet 105 into the pump chamber 106 and then pumped into the outlet 107 through the rotation of the moving part 102. A fluid is here a gas or, in particular, a liquid.
Since the moving part 102 acts as the rotor of the synchronous motor, no drive shaft is needed. The housing 101 is here closed off with respect to the stator. Therefore no seals or similar components are needed. Also, the moving part 102 is driven without gears, which saves not only the space for a gear train, but rather the drive for the pump 100 can also exhibit a very high efficiency.
b illustrates a section of the pump 100 along the axis of rotation of the moving part 102. The moving part here has eight vanes 108 (refer to
There is a permanent magnet 104 in each of the vanes 108. However, it is also conceivable that there is not a magnet 104 in each vane 108. Similarly it is also conceivable that there is a plurality of magnets 104 in some or all of the vanes 108. The surface of the moving part 102 may be of any desired material, for example stainless steel. Alternatively, the magnets 104 can also be fitted to the surface of the vanes 108.
Since the stator surrounds the moving part 102, it is advantageous to arrange the rotor magnets 104 in the vanes 108 situated as remotely as possible from the axle 110 in order to achieve the strongest possible coupling to the magnetic field of the stator coils 103. In this example the magnets 104 have approximately a radial separation from the axle 110 corresponding to at least 75% of the distance of a point on the edge of the vane 108, namely a point on the vane 108 with maximum distance to the axle 110.
The rotor magnets 104 in this example are permanent magnets. The stator and moving part 102 then form a permanently excited synchronous motor. The exciter power for the rotor coil can be saved, which is why an embodiment of this nature saves energy. Components, such as slip rings, brushes or similar components, for the transfer of the exciter power to the rotor can also be omitted. Since components which are subject to a high level of wear are involved, further operating costs are saved. In principle one, a plurality or all rotor magnets 104 can however also be electromagnets.
c illustrates a section of the pump 100 transverse to the axis of rotation of the moving part. The stator coils 103 are arranged along a circular path around the moving part 102 concentric to the axis of rotation. Here, the stator consists of six coils 103, which are arranged on the outer side of the housing 101. A different number of stator coils 103 is also conceivable. Alternatively, the stator 103 can consist of one or a plurality of travelling-field windings (refer to
The coils 103 can be fitted on the outside of the housing 101 such that the inner surface of the housing comprises any desired material, for example stainless steel. The coils 103 can also be fitted inside the housing 101 so that the inner and outer surfaces comprise any desired material, for example stainless steel. The coils 103 can also be embedded into the inner or outer sides of the housing 101, i.e. recessed in it to a certain depth. The coils 103 can also be fitted to the inner side of the housing 101 or spaced from the housing 101. The housing 101 can also have pegs, around which the coils 103 are wound, on the inner and/or outer surfaces. If the coils 103 are not delimited from the fluid by the housing 101, then the coils can be encapsulated.
The moving part 102 here has eight vanes 108, in each of which a permanent magnet 104 is located. In order to achieve the maximum coupling between the magnetic fields of the stator coils 103 and the rotor magnets 104, the rotor magnets 104 are here fitted in the ends of the vanes 108, i.e. the distance of the magnets 104 from the axle 110 corresponds to at least 75% of the distance of a point on a vane 108 with maximum distance to the axle 110. Of course, in other embodiments the magnets 104 can also have other minimum distances from the axle 110.
The surfaces of the vanes 108 are here parallel to the axle 110. It is however possible that the vanes 108 are turned or bent with respect to the axle 110, as is usual say with a propeller. Here, the vanes 108 are aligned radially. It is however conceivable that the vanes 108 are bent in the radial direction. It is also conceivable that the vanes 108 are bent in the axial and radial directions and then exhibit, for example, a scoop shape. The moving part 108 here is an open impeller wheel or impeller. The moving part 102 can alternatively also have a support disc with which the edges remote from the inlet 105 of one or a plurality of vanes 108 are joined. Then the moving part 102 is a semi-open impeller wheel. The moving part 102 can in addition also have a cover disc, which partially covers the side of the moving part 102 facing the inlet 105. The moving part 102 is then an enclosed impeller wheel.
a illustrates a perspective cutaway view of a centrifugal pump 200 with housing 201, moving part 202 and stator 203, whereby the moving part 202 partially encloses the stator 203, so that the moving part 202 rotates about the stator 203. During the operation of the pump 200 the fluid is drawn through an inlet 105 into the pump chamber 206 and then pumped into the outlet 207 through the rotation of the moving part 202.
b illustrates a section of the pump 200 along the axis of rotation of the moving part 202. The moving part 202 has one or a plurality of vanes 208 and a hub 209. The moving part can here be supported on an axle 210.
In this example the stator coils 203 are located in the axle 210, whereas the rotor magnets 204 are located in the hub 209 of the moving part 202. Alternatively, it is of course conceivable that the coils 203 are located on the inner and/or outer surfaces of the axle 210. It is also conceivable that the coils are embedded in the inner and/or outer surfaces of the axle 210, namely recessed in it to a certain depth. It is also conceivable that the axle 210 has pegs on the inner and/or outer sides around which the coils 23 are wound. The rotor magnets 204 can also be built into the vanes 208. Similarly, the magnets 204 can be fitted to the outer surfaces of the hub 209 or the vanes 208.
There are three stator coil rings 203 in the axle 210. For each stator ring 203 there is also an annular arrangement of rotor magnets 204 in the hub 209 (refer also to
c illustrates a section through the hub 209 and axle 210 of the pump 200 transverse to the axis of rotation of the moving part 202. In the illustrated cross-section three stator coils 203 are embedded in the axle 210 and four rotor magnets 204 in the hub 209 of the moving part 202. The three illustrated coils 203 here form one of the three stator rings 203. The ring formed by the rotor magnets 204 then belongs to the illustrated stator ring 203. In other embodiments the number of the stator coils 203 and the rotor magnets 204 can of course differ.
a illustrates a perspective cutaway view of a feed pump 300. The housing 301 has an approximate cylindrical shape. In particular the housing 301 here comprises a pipe segment. Other shapes, such as pipes with a polygonal cross section, are also conceivable. In terms of the process the pump 300 can be considered as a piece of pipe, during the installation of which no sump remains.
The moving part 302 is located in the housing 301. A number of stator coils 303 is arranged around the moving part 302 on a circular path concentric to the axis of rotation of the moving part 303 and is embedded into the outer side of the housing 301, i.e. recessed into it to a certain depth. One or a plurality of travelling-field windings (refer to
In this example the moving part has six vanes 308 curved in the radial direction to which rotor magnets are fitted on both sides. A different number of vanes 308 or a different vane shape is of course conceivable. The moving part 302 comprises a hub 309, which is supported on an axle 310. The axle 310 is fastened to the housing 301 with braces 311. In this example the axle 310 is fastened at each of both ends by three braces 311. A different number of braces 311 is also conceivable.
b illustrates a section of the pump 300 transverse to the axis of rotation of the moving part 302. In this example eight stator coils 303 are embedded into the outer side of the housing 301. A different number of coils 303 is of course conceivable. Also, the coils 303 can consist of one or a plurality of travelling-field windings (refer to
c illustrates a section of the pump 300 along the axis of rotation of the moving part 302. It can be seen that in each case a rotor magnet 304 is located on both sides of the vanes 308. Of course two magnets 304 need not be located on each vane 308. It is conceivable that on one or a plurality of vanes 308 only one or even no magnet 304 is fitted.
d illustrates a side section of another embodiment of the pump 300 in which it is a screw pump. Also in this example the housing 301 is approximately cylindrical. In terms of the process the pump 300 can be considered as a pipe and can be joined to the rest of the pipe system by flange joints 313.
The moving part here comprises no vanes as such, but rather a spiral 308. Here, this spiral 308 has, for example, a permanently magnetic core 304, i.e. the spiral 308 consists of a plurality of layers, of which a central one is permanently magnetic. The moving part 302 also comprises a hub 309 here, which is supported on an axle 310. The axle 310 is in each case fastened to the housing 301 at both ends with braces 311.
Due to the large axial expansion of the moving part, the stator here comprises three stator rings 303, whereby each stator ring 303 consists of a number of stator coils arranged in a ring shape. Of course a different number of stator rings 303 is conceivable. Diverse stator rings 303 can by all means here comprise diverse numbers of coils.
e illustrates a side section of another embodiment of the pump 300 in which it is an eccentric pump. In this example the inner side of the housing 301 has the shape of a geometrical rotational body with wave-shaped envelopes. The moving part 302 has the shape of a helical shaft, which can rotate in the housing 301 about its geometrical axis of rotation. The stator coils 303, which for example are wound about the pegs 312 on the outer side of the housing 301, are arranged concentrically with the geometrical lines of rotation of the crest points of the envelopes of the geometrical rotational body. The rotor magnets 304 are then preferably arranged on and/or in regions of the helical shaft 302, which are approached as close as possible by the stator coils 303 during a rotation.
f illustrates a side section of another embodiment of the pump 300. The moving part 302 here comprises scoop-shaped moving elements 308, which are partially covered with a permanently magnetic material 304. The moving part comprises a hub 309, which is supported on an axle 310. The axle 310 is in each case fastened to the housing 301 at both ends with braces 311. The stator coils 303 are in this example fitted on the inner side of the housing 301. Then the stator coils 303 are encapsulated to delimit them from the fluid. Also, this pump 300 can be integrated into a pipe system using flange joints 313.
a illustrates an example in which the device is a double-acting reciprocating pump 400. Here, the moving part 402 is a piston which moves linearly. The fluid is drawn through two inlets 405-1 and 405-2 into the respective pump chambers 406-1 and 406-2 and then pumped into the respective outlets 407-1 and 407-2. Of course, a single-acting reciprocating pump is also conceivable, say in that the elements 405-2, 406-2 and 407-2 are disregarded. In this example the piston 402 moves linearly along the stator 403 enclosing it and between the pump chambers 406-1 and 406-2.
b illustrates a variant of a linear drive of a reciprocating pump of this nature. The housing 401 is here approximately cylindrical between the pump chambers 406-1 and 406-2. The stator coils 403 are formed, for example, by three windings 416-1, 416-2 and 416-3, which are wound along a length around the housing 401 between the pump chambers 406-1 and 406-2. The three windings 416-1, 416-2 and 416-3 here correspond to the three phases of the rotary current. The number of windings 416 can be correspondingly adapted for alternating current with a different number of phases. In and/or on the piston 402 permanent magnets 404 are arranged in each case with opposite poles in a row along the movement path of the piston 402. Here, the arrangement does not need to be geometrically perfect. Thus, the magnets 404 can also be arranged offset.
c illustrates another variant of a linear drive of a pump of this nature. In this connection one or a plurality of long stators 403 are used, i.e. the stators 403 are provided in each case with one or a plurality of travelling-field windings (refer to
d illustrates a plan view of a variant of a travelling-field winding 403 from
a illustrates a side section of a stirrer 500. The housing 501 here comprises a pot, which acts as a stirring chamber inside. In this is located a moving part 502, which comprises one or a plurality of agitator blades 508 for stirring, mixing or blending one or a plurality of fluids. The moving part 502 comprises a hub 509, which is supported on an axle 510. The stator coils 503 are here embedded into the outer surface of the housing 501. The moving part 502 has in each case in its vanes 508 two magnets 504-1 and 504-2, whereby the magnet 504-1 is integrated into the outer region 518 and the magnet 504-2 is integrated into the lower region 519 of the vane 508.
b illustrates a bottom view of the stirrer 500. Two stator coil rings can be seen, of which one is formed by the stator coils 503-1 on the side wall of the housing 501 and the other by the stator coils 503-2 on the bottom side of the housing. Both rings are concentric with the rotational path of the rotor magnets 504-1 and 504-2 during operation of the device. The ring of the coils 503-1 here is located for example at the height of the rotor magnets 504-1, whereas the ring of the coils 503-3 is located below the magnets 504-2.
c illustrates the side section of another embodiment of the stirrer 500, whereby the moving part 502 comprises a hub 509, which is supported on an axle 510. The axle 510 including the moving part 502 can here be introduced into the housing 501 from above. In this case the brace 513 can for example be joined to a lid 520 or other cover of the stirrer. The moving part 502 has one or a plurality of vanes 508. In and/or on the outer region 518 of the moving part 502 a magnet 504-1 is fitted here in each case, whereas in and/or on the lower region 519 of the moving part 502 two magnets 504-2 and 504-3 are fitted here in each case. Accordingly, a respective number of coils 503-1, 503-2 and 503-3 form three stator coil rings, corresponding to the rotational paths of the stator magnets 504-1, 504-2 and 504-3, as illustrated in
d illustrates a side section of another embodiment of the stirrer 500, whereby the moving part 502 envelopes the stator 503 at least partially. The stator 503 is here located on a peg 510 of the housing 501 and is partially enclosed by the hub 509 of the moving part 502. The vanes 508 of the moving part 502 then rotate around the stator during operation of the device. The rotor magnets 504 of the moving part 502 are advantageously arranged in and/or on the hub 509.
It is self-evident that the features mentioned in the previously described embodiments are not restricted to these particular combinations and are possible in any other combinations.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2011 075 097.5 | May 2011 | DE | national |
