Abstract:
A pump arrangement having a unit which comprises a material with a magnetocaloric action, an arrangement of conduits which are in the region of the unit and through which a liquid or gaseous heat-conduction medium flows and a pump system operating according to travelling-wave principles.

Description:
[0001]    Devices using the “magnetocaloric effect” phenomenon to work as heat pumps have been known for quite some time. In these devices, materials which have the magnetocaloric effect are periodically exposed to a magnetic field. Under the influence of the magnetic field, the specific heat capacity or thermal storage capacity of the material changes. 
         [0002]    By supplying and discharging media (gases, liquids), the device may be supplied with thermal energy, which can be transformed to a different temperature level and then be discharged. For the supply and discharge of media, pump systems are required. These pump systems must operate with low-maintenance and good efficiency. In the following, a pump system is disclosed which is particularly well suited for this application. 
       STATE OF THE ART 
       [0003]      FIG. 1  shows an assembly  1 , to which a medium having a temperature δ 1  is supplied, and from which a medium with temperature δ 2  is discharged. In order to produce the effect of temperature transformation, preferably rotary energy is input into such an assembly. Due to the relatively large thermal time constants of the components used in the units, the rotational frequency of the rotational motion induced in the assembly by external drives must be low (in particular between 0.5 Hz and 20 Hz, preferably in the range of 1 Hz to 10 Hz). These external drives can be formed, for example, by a combination of distinctly faster running, generally cylindrical shaped, electric motor  2  and a reduction gear  3 . 
         [0004]    A distinctly disc-shaped, slow-running motor  4  is significantly more compact, quieter, lower-maintenance and more energy efficient. The motor  4  can be particularly advantageously designed as a multi-pole axial flux motor. In  FIG. 2 , such a motor is illustrated as an asymmetrical (one sided) axial flow motor. It is designed as a synchronous motor and consists of a stator  5  and a rotor  6 . A torque, and thus rotational motion, is generated in the permanent magnets  7  fixed to the rotor  6  by applying a rotating field to the coils  8 . The torque can be transferred via the shaft  9 .  FIG. 3  shows an analogous device in the form of a symmetrical structured double-sided axial flow device. Also suitable for the above purpose is the use of a permanent magnet synchronous device according to the external rotor principle (see  FIG. 4 ). Characteristic of both engine variants is the cavity between the rotor and stator. 
     
    
     DESCRIPTION OF THE INVENTION 
       [0005]    The gap between the rotor and stator is in this case a particularly good way to house one or more pumps for transporting the heat conducting medium. 
         [0006]    Considering the optimal spatial and functional integration of the entire assembly and in view of the set drive characteristics with the low speed, it has been shown to be advantageous to make use of pump systems working on the traveling wave principle. Such pump systems are described for example in the European patent EP 1317626 B1. 
         [0007]      FIG. 5  shows how to put a pump system in an annular groove on the stator  5  according to the traveling wave principle. By the rotational movement of the rotor  6 , the cam  10  periodically passes over the membrane assembly  11 , whereby a liquid or gaseous medium can be conveyed via the connections  12  and  13 . The cross-section of the tubular membrane arrangement  11  corresponds to the arrangement described in the European patent EP 1317626 B1. The pump can be operated virtually without wear and is virtually maintenance-free, quiet and efficient. In accordance with the principle of the traveling wave pump, no seals on moving parts are needed. Since little friction occurs between the cam  10  and diaphragm assembly  11 , the components involved are hardly subject to wear. As this pump arrangement can work by displacement or as a flow pump (e.g., via adjustable cam height), a wide range of pressure levels, for example in the range from 10 mbar to 20 bar, can be realized. Further, a not shown means for providing a variable magnetic field is provided. 
         [0008]      FIG. 6  shows a further development of the arrangement with two independent media circulations via another concentric membrane assembly  14  and another cam  15 . Via the connections  16  and  17  another media circuit can operate. Furthermore,  FIG. 6  shows that the membrane assemblies  11  and  14  would also be possible in different cross-sections (widths, heights). Therewith, for example, the different radial rotational speeds of the cam can be compensated to achieve the same flow rates in both circuits. However other mixed modes with different flow rates or pressure levels can be realized. 
         [0009]    Similarly, further, in particular concentric, arrangements for other circuits are conceivable and possible. 
         [0010]      FIG. 7  shows a further development of the previous arrangement for a symmetrical (two-sided) designed axial flow, which as stated above can be realized in different variants. 
         [0011]      FIG. 8  shows radially a circumferentially segmented arrangement. Segmentation can be implemented in any number and shape. 
         [0012]      FIG. 9  shows an arrangement with a plurality of cams per orbit (any number and shape imaginable). 
         [0013]      FIG. 10  shows further locations for the membrane assemblies. 
         [0014]      FIG. 11  shows analogous conceivable positions of membrane assemblies in a permanent magnet synchronous machine according to the external rotor principle. 
         [0015]    If a motor of a different design, for example by the internal rotor principle is used, the considerations are analogous between two plane-parallel plates or between respective radial hollow spaces between an inner and an outer wall of two cylindrical assemblies in or on the magnetocaloric unit. 
         [0016]    In particular, it may be provided that, to improve efficiency of the arrangements, measures may be taken to reduce the friction and in particular between the membrane  11 ,  14  and the cams  10 ,  15 . To that extent, the already low friction be further improved by the provision of rollers or by improving the sliding property - for example by coating the membrane  11 ,  14  respectively or the cams  10 ,  15 . 
         [0017]    The disclosed embodiments of the invention can be combined. They are each an example, of which individual features of the embodiments by themselves are or may be essential to the invention. In addition, the pump system is merely exemplary housed in the gap between the rotor and the stator. Basically, the pump system can be arranged between any relatively moving components of the pump assembly or the drive unit. Further, the motor can be positioned to the side of the assembly or be integrated within the assembly at any point. In this respect, there results an integrated implementation with small space.