GB2163977A - Magnetic filter - Google Patents

Abstract

A magnetic filter assembly for the removal of components which may be magnetized from suspensions and fluids. The magnetic filter assembly may be cleaned without a high labour and apparatus requirement. The risk of mechanical destruction of the matrix elements is avoided. The matrix does not have to be separated into its component elements for cleaning. The matrix elements of the magnetic filter are disposed in a matrix container, and are removable therewith from a magnetic field. The container walls may be permeated by suspensions and fluids, and the container base is an element supporting the matrix elements and may be formed as a ring, a holding jaw, a perforated base, a grid base or a grate-type base. The matrix container consists of material with perforations, metal mesh, fabric or bar material. Spacers may be disposed between the matrix elements. Its main field of application is the removal of strongly magnetic impurities from ceramic sludge. <IMAGE>

Description

SPECIFICATION Magnetic filter assembly for the removal of com- ponents which may be magnetized from suspensions and fluids Applications of the invention The invention relates to a magnetic filter assembly for the removal of components which may be magnetized from suspensions and fluids which may be used in all cases in which components which may be magnetized are to be removed from fluids and suspensions.

!ts main field of application is the removal of strongly magnetic impurities from ceramic sludge.

The invention may be used both for new magnetic filter constructions and to equip magnetic filters already in use.

Prior art On the basis of the filter system, current magnetic filters generally comprise a magnet system and a magnetic filter assembly located therein.

Known magnetic filter assemblies comprise superposed matrix elements which may be permeated -by suspensions, in which the matrix elements may be separated from one another by spacer elements. The matrix elements are disposed one above the other and are in most cases centered on a rod or a tube by means of an opening in the centre, which serves to fix the position of the matrix elements in the magnetic filter and simultaneously provides the possibility of removing all the matrix elements from the magnet system at once.

During the filter process, the suspension to be cleaned flows through the filter assembly and ferromagnetic components are deposited at the filter assembly and coarse components are mechanically retained. These magnetic filter assemblies must be cleaned at regular intervals in order to dispose of the components retained by magnetic and by mechanical forces.

In accordance with the respective construction of the magnetic filter, it is conventional to clean the magnetic filter assembly by flushing the matrix out with water or a water/air mixture, wherein vibrations or an attenuating alternating field may be used as an auxiliary means designed to overcome adhesion or to counter remanence.

In the case of these methods, cleaning involves high power consumptions and the use of costly auxiliary assemblies as well as a frequent flushing out. A further possibility for magnetic filters, which are not provided with these auxiliary assemblies, is to remove the filter assembly from the magnet system and to clean it subsequently with a fluid or a gas/fluid mixture outside of the magnet system.

This also involves cleaning in which it is necessary to dismantle the matrix and reconstruct it again.

This prior art has many drawbacks. High mechanical stresses on the matrix elements which are stacked loosely on a central guide during removal from and insertion into the magnet system require the matrix elements to be very stable and therefore require costly production techniques and the use of mechanically stable materials.

The dismantling, cleaning of the matrix elements and subsequent reconstruction required after each operating cycle is costly in terms of time and labour.

Use must be made of costly apparatus, power and control techniques during cleaning of the matrix in the magnetic filter in the case of use of water/air pressure cleaning and the use of vibrations or demagnetization or the combination thereof.

There is no optimum use of the cross-section available as a result of the central mounting.

Aim of the invention The aim of the invention is therefore to provide a filter assembly construction, in which the matrix elements are not subject to mechanical stresses during the required insertion into and removal from the magnet system, in which it is possible to use magnetic materials which have a low degree of mechanical stability, in which the there is a low power consumption and the cost of additional apparatus for cleaning the filter assembly is low and in which the cross-section available may be increased whilst the filter assembly diameter remains the same.

Description of the invention The object of the invention is to avoid large-scale mechanical stresses on the matrix elements, to enable the use of any material which may be magnetized, to allow for a simple manufacture of the matrix elements and to make optimum use of the flow surface as well as to reduce the high power, apparatus and time requirements for the cleaning of the matrix. In accordance with the invention, this object is solved in that the matrix elements of the magnetic filter are disposed in a container. An advantageous embodiment of the invention is formed by a perforated container wall which may be permeated by fluids or suspensions. Materials with perforations, metal mesh, fabric or bar material may be used for the container wall. The lower limit of the matrix container must be an element which supports the matrix elements and may, however, be substantially open.The lower limit of the matrix container may be formed as a ring, a holding jaw, a perforated base, a grid base or a grate-type base. In addition, it is advantageous for spacers to be disposed between the matrix elements.

The matrix assembly described above is disposed in a magnet system. When a magnetic field is applied, the medium to be cleaned flows through the filter asembly, and the ferromagnetic components are deposited on the matrix elements.

Coarse particles are mechanically retained. At the end of the operating cycle, the filter assembly is removed from the magnet system and may be cleaned by a water jet. In this respect, the preforation in the casing and the base as well as the spacers ensure that all the points of deposition in the matrix are satisfactorily reached by the cleaning jet. The filter assembly is then ready for use again.

The invention is described in more detail below with reference to embodiments thereof.

Example 1 In the embodiment of Figure 1, there is shown a matrix container in which there are disposed matrix elements 1 which are separated from one another by spacers 2. The matrix elements are formed as discs T which are supported on a container base 3. The discs 1 are centered in the middie by a guide rod 4.

The container wall 5 is a metal cylinder which is provided with round perforations 6. The container base 3 is formed as a round base with perforations 7.

Example 2 In the embodiment of Figure 2, the matrix container is also a metal cylinder in which disc matrix elements 10 are used and the lower limit is a ring 12 on which the matrix elements 10 are supported and are separated from one another by intermediate rings 11 with ribs.

Example 3 In the embodiment of Figure 3, the matrix container is produced from bar material 13, in which the matrix elements are also spaced by intermediate rings 15 with ribs and the matrix elements are held by the jaws of the bent rods 16. There is no centering in the middle in this case.

Example 4 In the embodiment of Figure 4, the matrix container is formed by a cylinder whose cylinder walls are formed by a fabric 17 which may be permeated by suspensions and whose base is formed by a plate with perforations 18, which plate is positively and frictionally connected with the cylinder wall.

The present invention has the following advantages: - Protection of the matrix elements against mechanical stresses and destruction, - Simple manufacture of the matrix elements, - Low power, apparatus and time requirements for cleaning, - Increases in the working cross-section available whilst the assembly size remains the same, - Use of magnetic materials having a lower degree of mechanical stability.

Claims (9)

1. A magnetic filter assembly for filtering in a magnetic field components which may be magnetised, from fluids and suspensions, comprising a plurality of filter elements contained in a container which may be removed together with the filter elements from the magnetic field.

2. A magnetic filter assembly as claimed in claim 1, wherein the container walls are perforated.

3. A magnetic filter assembly as claimed in claim 1, wherein spacers are disposed between the matrix elements.

4. A magnetic filter assembly as claimed in claim 1, wherein the base of the container forms a mounting for the lowermost filter element and also contains at least one opening for flow of fluid therethrough.

5. A magnetic filter assembly substantially as hereinbefore described with reference to any one of the accompanying drawings.

6. A filtering arrangement comprising, means for establishing a magnetic field, a container containing a plurality of filter elements to collect components from a fluid supply by magnetic interaction with the field, wherein the container is removable from the field to permit cleaning of the filter elements.

7. A method of cleaning the filtering arrangement of claim 6 including removing the container from the field, cleaning particles from the filter elements without removing the elements from the container, and then returning the container to the magnetic field.

8. A method as claimed in claim 7 including washing the removed container and the filter elements with a water jet.

9. A method of cleaning a magnetic filter substantially as herein described with reference to the accompanying drawings.