GB2133225A

GB2133225A - Electromagnetically operated conveying device

Info

Publication number: GB2133225A
Application number: GB08334597A
Authority: GB
Inventors: Reiner Martin; Max Muhlig; Dieter Naundorf; Klaus Nitsche; Rudiger Salomon
Original assignee: Carl Zeiss Jena GmbH
Current assignee: Jenoptik AG
Priority date: 1982-12-31
Filing date: 1983-12-30
Publication date: 1984-07-18
Also published as: DE3338626A1; DD213265A1; GB8334597D0

Abstract

An electromagnetically operated conveying device comprises a container (1) which is embraced by one or more coils (3, 4). The housing contains a magnetizable medium which acts as an armature for the or each coil (3, 4). Upon change of the energisation of the coil or coils the magnetizable medium is displaced within the housing. A means is provided for translating the movement of the fluid into useful work. <IMAGE>

Description

SPECIFICATION Electromagnetically operated conveying device The invention relates to electromagnetically operated conveying devices.

Presently such devices as, for example, pulling magnets, lifting magnets, oscillating armature motors and electromagnetic pumps are known as devices for converting alterations of an electric current into variations of power, variations of position and variations of shape, respectively.

Apart from the devices mentioned hereinbefore, others of such kind are known which work by utilizing the piezoelectric properties of crystals (DE 23 54 229, DE 30 07 001) or by utilizing the magnetostrictive properties of ferro-magnetic material (DE 21 63 667). Since a variation of shape and volume also occurs in the case of utilizing the piezoelectric properties of crystals as in the case of utilizing the magnetostrictive properties of ferromagnetic material, the useful power effects obtainable by means of those variations are very low. Therefore, these considerable variations of volume and, hence, of power effects demand accordingly larger starting quantities of material.

Oscillating armature motors and eiectromagnetic pumps are disclosed in patent specifications Nos. DE 16 53 563, DE 21 06 055, DD 143650 and DD 151 207, and in almost all cases they have the same basic principle, as follows: An electromagnet and a core form a magnetic assembly, with the core being moved upon current flow through the magnetic field, preferably into the coil. In these devices, the reverse movement of the core is achieved by the tractive force of a spring (DE 1 6 53 563, DD 143 650, DE 21 06 055). In an adjacent chamber provided with valves, the moving core produces a pressure variation which appears at these valves as a pumping effect (DE 1 6 53 563). In Utility Model No. 30 028, the core is embodied as a push rod having approximately the shape of the pump chamber.The shockwise stress on the diaphragm leads to a very severe deformation and, hence, to early destruction of it.

A water pump disclosed in patent specification No. DE 807 058 operates with a very strong electromagnet, which requires a solid construction of the armature. Therefore, extremly high stresses act on the metal diaphragm. For that reason, early crack formations and fatigue phenomena are typical in such a pump.

The above-described possibilities for converting alterations of electric current into mechanical power effects are based on the principle that a solid core of a magnetic material is moved through the creating or decaying magnetic field of a coil. In spite of the provision of special guides, jamming and canting, of the core within the coil may occur.

For sealing the pump chamber, diaphragms are used, the elastic deformation of such diaphragms causing the transmission of pressure or power.

Although the shape of the armature is designed in relation to the dimensions of the pump chamber and the diaphragm, an intermittent, powerful, shocklike stress on the diaphragm can not be avoided. Furthermore, only part of surface of the diaphragm is utilized for the transmission of power. For these reasons the failures of the diaphragms mentioned above occur. Moreover, the movement of a solid body tends to be accompanied by a high noise level.

The disadvantage of the arrangements based on the coil with movable core principle, for instance embodied as a pulling magnet, resides in the fact that the transmission of power is only carried out via the cross-sectional area of the core which must be designed suitabiy. This means that an even transmission of power to the area of the diaphragm or of the core is not possible.

Furthermore this means that, due to the different cross-sectional areas of the diaphragm and of the core, only a proportion of the power of the magnetic filed is transmitted to the diaphragm or the other coupling members.

It is an object of the present invention to obviate the above disadvantages.

In accordance with the present invention, there is provided an electromagnetically operated conveying device comprising a container, at least one coil which encompasses the container, the container housing a magnetizable medium in the form of a magnetic fluid which forms an armature of the coil such that, upon change of the energisation of the coil, the magnetizable medium is displaced within the housing.

One embodiment comprises at least two said coils, the coils being electrically coupled to an electronic commutator which, in turn, is electrically coupled with a power supply unit.

Advantageously, the container has openings.

The electronic commutator comprises an input for connecting the power supply unit, outputs for connecting the coils, and members for the connection of the power supply unit to the coils under variable control with time. Preferably, the power supply unit provides electric current of a definable characteristic. Advantageously, the container has the magnetic fluid in the range of the coils only. Preferably, the container includes means for the fixation of the position of the magnetic fluid. These means are, for example, elastic diaphragms or permanent magnets.

For pressure compensation and for transmission of power the container can have openings which include sealing elements such as, for example, suction sealing elements or displacement sealing elements. It is an advantage to connect the magnetic fluid to an operating means via a pressure transmitter. Advantageously, the pressure transmitter is a gaseous liquid or a solid medium. The pressure transmitter can also be an elastic diaphragm. On the other hand, the magnetic fluid can advantageously be connected to the operating means directly.

The electromagnetically operated conveying device according to the invention is characterised by a simple construction and a reliable mode of operation.

It is an important advantage of the invention to convert the alterations of an electric current into mechanical kinetic energy by means of a magnetic -field, without the aid cf additional mechanically moved elements. A magnetic fluid serves as a power transmitting medium which has negligible friction and the movement of which does not cause any noise. Thus, one of the most frequent reasons for failures up to now - which is the elastic diaphragm -- can be eliminated.

The present invention will now be described and illustrated, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a sectional view of one embodiment in accordance with this invention, in the form of a diaphragm pump; Fig. 2 shows a detail of the embodiment of Fig.

1, the diaphragm being omitted and comprising a ring-magnet; and Fig. 3 shows an electromagnetically operated conveying device in accordance with the invention in the form of a pulling magnet.

Fig. 1 shows a container 1 having an elongate shape of circular cross-section. A magnetic fluid 2 is contained in a central portion of the container 1 which lies between the elastic diaphragms 7. The coils 3 and 4 encompass part of the central portion of the container 1, the coils 3 and 4 being coupled via respective signal connections 14 to an electronic commutator 5 which, in turn, is electrically coupled to a power supply unit 6.

The position of the magnetic fluid 2 in the central portion of the container 1 is limited by the two elastic diaphragms 7. The container 1 extends beyond each of the diaphragms 7 to form two pump chambers 1.1 and 1.1' at the respective end portions of the container 1. These pump chambers 1.1 and 1.1' have each two openings 12 and 13.

The openings 12 form inlets which each include a suction sealing element 8, while the openings 1 3 form outlets each of which includes a displacement sealing element 9. The elements 8 and 9 are functionally coupled with one another.

Fig. 2 shows a part of the central portion of the container 1 in detail, with the position of the magnetic fluid 2 being limited by the magnetic field of an annular magnet 10.

The diameter of the container 1 is selected depending on the properties of the magnetic fluid 2 and on the field intensities obtainable with the coils 3 and 4. Any nonelastic material is suitable to be used as a material for the container 1. The coils 3 and 4 serve to hold the magnetic fluid 2 in the central portion of the container 1 by means of the magnetic field which is established around the coils 3 and 4. To eliminate variation of the position of the magnetic fluid 2 and to obtain a physical separation of this fluid 2 from the air in the adjacent pump chambers 1.1 and 1.1', the elastically deformable diaphragms 7 are provided.

The container 1 is sealed by the self-acting components 8 or 8' and 9 or 9' which open or close for suction and displacement of the air contained in the pump chambers 1.1 and 1.1'. The coils 3 and 4 are alteratingly supplied with alternating voltage by the power supply unit 6 via the electronic commutator 5. The magnetic field created around the respectively connected coil 3 or 4 causes a symmetrical arrangement of the magnetic fluid 2 relative to the corresponding coil.

Consequently a mechanical pressure is exerted on the respective one of the diaphragms 7, which results in an elastic deformation of the latter. This causes the formation of a low pressure in one of the adjacent pump chambers 1.1 or 1.1' and the formation of a positive pressure in the other of these pump chambers. Accordingly, these low or positive pressures cause the sealing elements 8 or 8' and 9 or 9' to open or close, respectively. In other words, the sealing element 8 or 8' opens when the pump chamber 1.1 or 1.1' is under low pressure and, on the other hand, the sealing element 9 or 9' closes under low pressure and opens under positive pressure. Hence, the medium air container in the pump chamber 1.1 or 1.1' is moved from the inlet 12 or 12' to the outlet 13 or 13'.Therefore, by means of the constantly changing activation of the coils 3 and 4, a corresponding movement of the magnetic fluid 2 in the cnetral portion of the container 1 is obtained which is variably controlled with time by way of the electronic commutator 5.

The power effect of the electric current, which becomes effective via the magnetic fluid 2, and which is being converted into a mechanical movement, can be taken off efficiently in different ways. This function is also obtainable with the diaphragms 7 omitted. However, to eliminate a separation of the magnetic fluid 2 and frothing when it is used, for instance, in a vibrating engine, an annular magnet 10 (see Fig. 2) is included which acts to retain the magnetic fluid 2. At the same time, it holds together the magnetic fluid 2 in the central portion of the container 1 when the coils 3 and 4 are entirely switched off. Hence, the diaphragms 7, which are a frequent cause of failure, can be ommitted. The power effect trasmitted by the magnetic fluid 2 can be used directly via power pistons (not shown) or the like, without physical diaphragms. The utilization of the magnetic fluid 2 as a pressure transmitter is feasible as well.

The sectional view of Fig. 3 shows a container 1 in a central portion of which a magnetic fluid 2 is held by the coil 3 encompassing this part. The magnetic fluid 2 is separated from the adjacent parts of the container 1 by two diaphragms 7. One of the diaphragms 7 serves for transmitting the power onto an operating cylinder 11. The representation of the functional blocks required for the build-up of the magnetic field by the coil 3 has been omitted.

The mode of operation is analogous to the conveying devices shown in the Figures 1 and 2.

In this case also, the coil 3 causes a symmetrical distribution of the magnetic fluid 2 in the container 1. In the absence of the magnetic field of the coil 3 the elastically deformable diaphragms 7 act as a repelling power. However, it is also feasible to omit the diaphragms 7 with the resetting power then being produced by an air cushion 1 5 under positive pressure.

The latter modification of the arrangement illustrated in Fig. 3 is especially favourable for non-repeated power effects as typified by lifting and pulling magnets. The power transmission can take place in different ways, similar to the embodiments of Figures 1 and 2.

The invention is not restricted to the illustrated embodiments, however variations can be achieved, for example, in accordance with the following: The activation frequency for the electronic commutator 5, the type of the activation of the coils 3 and 4, and the electric current provided by the power supply unit 6 depend to a large extent on the intended purpose of the conveying device and its constructional set-up. In particular, the shape and construction of the container 1, of its sealing elements 8 and 9, of their number and arrangement and of the coils creating the magnetic field around the magnetic fluid 2 can be modified. To use a different number of coils for the achievement of a variation of the position of the magnetic fluid 2 can be advantageous. The medium provided in the pump chambers 1.1 and 1.1' may be other than that described hereinbefore.

Claims

1. An electromagnetically operated conveying device comprising a container, at least one coil which encompasses the container, the container housing a magnetizable medium in the form of a magnetic fluid which forms an armature of the coil such that, upon change of the energisation of the coil, the magnetizable medium is displaced within the housing.

2. An electromagnetically operated conveying device as claimed in claim 1, comprising at least two said coils encompassing the container, the coils being electrically coupled to an electronic commutator which, in turn, is electrically coupled with a power supply unit.

3. An electromagnetically operated conveying device as claimed in claim 2, wherein the container has openings.

4. An electromagnetically operated conveying device as claimed in claim 1 or 2, wherein the electronic commutator has an input for connecting the power supply unit and outputs for connnection to the coils.

5. An electromagnetically operated conveying device as claimed in claim 4, wherein the electronic commutator comprises members for the connection of the power supply unit to the coils under variable control with time.

6. An electromagnetically operated conveying device as claimed in claim 2, wherein the power supply unit is a current source providing electric current of a predetermined characteristic.

7. An electromagnetically operated conveying device as claimed in claim 6, wherein the power supply unit is a direct-current source.

8. An electromagnetically operated conveying device as claimed in claim 6, wherein the power supply unit is an alternating-current source.

9. An electromagnetically operated conveying device as claimed in claim 2, wherein the magnetic fluid is disposed within the container in the range of the coils only.

10. An electromagnetically operated conveying device as claimed in claim 9, wherein the container includes means for the fixation of the position of the magnetic fluid.

11. An electromagnetically operated conveying device as claimed in claim 10, wherein the fixation means are elastic diaphragms.

12. An electromagnetically operated conveying device as claimed in claim 1 0, wherein the fixation means are permanent magnets.

1 3. An electromagnetically operated conveying device as claimed in claims 2 and 3, wherein the openings include sealing elements.

14. An electromagnetically operated conveying device as claimed in claim 13, wherein the sealing elements are suction sealing elements and displacement sealing elements.

1 5. An electromagnetically operated conveying device as claimed in claim 2, wherein the magnetic fluid is connected to an operating means via a pressure transmitter.

1 6. An electromagnetically operated conveying device as claimed in claim 1 5, wherein the pressure transmitter is a gaseous, liquid or solid medium.

1 7. An electromagnetically operated conveying device as claimed in claim 15, wherein the pressure transmitter is an elastic diaphragm.

1 8. An electromagnetically operated conveying device as claimed in claim 2, wherein the magnetic fluid is connected to the operating means directly.

1 9. An electromagnetically operated conveying device substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.