MCALLORUM, Steve (Eclipse Magnetics Limited, Gate Number 2Atlas Way, Atlas North, Sheffield, GB)
| Claims
1. A magnetic separator comprising a seal wherein the seal comprises a magnetic detectable material.
2. A magnetic separator in accordance with claim 1 in which the seal is resilient.
3. A magnetic separator in accordance with claim 1 or claim 2 in which the seal is an annular seal.
4. A magnetic separator in accordance with any preceding claim in which the magnetic detectable material comprises a ferrous material.
5. A magnetic separator in accordance with any preceding claim in which the magnetic detectable material comprises iron.
6. A magnetic separator in accordance with claim 5 in which the iron comprises iron filings.
7. A magnetic separator in accordance with any preceding claim in which the seal comprises a circular annular seal.
8. A magnetic separator in accordance with claim 7 in which the circular annular seal has a circular outer profile and an inner circular profile.
9. A magnetic separator in accordance with claim 8 in which the outer profile and the inner profile comprise concentric circles.
10. A magnetic separator in accordance with any preceding claim in which the seal comprises a shaped cross sectional profile.
11. A magnetic separator in accordance with claim 10 in which the seal comprises a substantially "C" - shaped crossed sectional profile.
12. A magnetic separator in accordance with claim 10 or claim 11 in which the seal comprises an inwardly facing channel shaped cross-section.
13. A magnetic separator in accordance with any one of claim 10 to claim 12 in which a cross-section of the seal defines a mouth portion which is arranged to locate over and around a frame member in order for an inner surface of the seal to locate adjacent to an outer surface of the frame member.
14. A magnetic separator in accordance with any preceding claim in which the seal is arranged, in use, to be retained around an outer frame member by an interference fit.
15. A magnetic separator in accordance with any preceding claim in which the seal comprises coloured material in order for fragments of the seal to be visually identifiable.
16. A magnetic separator in accordance with any preceding claim in which the seal comprises a static dissipative material.
17. A magnetic separator in accordance with any preceding claim in which the seal comprises an extruded strip which may be subsequently cut and bonded or otherwise secured to form an annular ring.
18. A seal for a magnetic separator wherein the seal comprises a magnetic detectable material.
19. A method of sealing a magnetic separator within separating apparatus, the method comprising locating a seal around an outer frame member of the magnetic separator and wherein the seal comprises magnetic detectable material.
20. A magnetic separator comprising a seal substantially as herein described with reference to, and as shown in any of the accompanying drawings.
21. A seal for a magnetic separator substantially as herein described with reference to, and as shown in any of the accompanying drawings.
22. A method of sealing a magnetic separator within separating apparatus substantially as herein described with reference to, and as shown in any of the accompanying drawings. |
IMPROVEMENTS IN AND RELATING TO SEALS FOR A MAGNETIC
SEPARATOR
Field of the Invention
The present invention relates to seals and particularly, although not exclusively, to seals surrounding vibrating magnetic separators located in separating apparatus for use within the food and pharmaceutical industries.
Background to the Invention
Food production systems may include several processing stages and associated apparatus. This may include separating apparatus which is arranged to separate and remove contaminants from the material being processed. This is particularly relevant where the material is digestible and is intended for human consumption. This is additionally relevant where the contaminant may pose a health and/or safety risk.
Accordingly, magnetic separators are frequently used to extract magnetic (and paramagnetic) particles and fragments from processing material, in particular, powders, granulates, liquids, solutions etc. The present invention is primarily for use with dry materials and dry free flowing products. These magnetic separators may comprise a magnetic grid formed from a number of parallel linear magnetic rods which are supported by an outer frame member. The magnetic separator is then secured within the separating apparatus of a processing system such that the processing material is required to flow through the magnetic grid and the magnetic members may then extract magnetic contaminants. The separating apparatus comprises a inflow region (for example a hopper) and an outflow region such that in use, the processing material is poured into the hopper and then passes through the magnetic grid and then flows out of the outflow region and into further processing apparatus.
The magnetic separator includes a seal which surrounds a part of an annular frame member of the magnetic separator in order to seal the magnetic separator in position in the processing apparatus. This seals the magnetic separator in the processing apparatus and ensures that the processing material passes through magnetic separator or more specifically through a magnetic grid.
In order to aid the flow of material through the magnetic separator and to increase the effectiveness of the magnetic separator, the magnetic separator is arranged, in use, to vibrate or oscillate. In particular, the magnetic separator is driven at a high frequency.
The magnetic separator may comprise a solid tubular metal outer frame and solid metal magnetic members. Accordingly, since the mass of the magnetic separator may be relatively high, the vibration of the magnetic separator may produce significant momentum and inertia forces. These forces cause mechanical fatigue in the apparatus and components. In particular, if the seal comprises a perishable rubber then this can cause the seal to fail and/or may cause particles of the seal to become separate and mix with the processing material. Accordingly, these fragments of seal may act as contaminants in the processing material.
Due to the aforementioned high frequency oscillations of the magnetic separator, the seal is the subject of high wear and may at least partially fail with time. Such failure, especially if relatively minor, may not be readily detectable by an operator. In addition, any fragments from the seal may enter the processing material and subsequently enter the food or pharmaceutical product.
It is an aim of the present invention to overcome at least one problem associated with the prior art whether referred to herein or otherwise.
Summarv of the Invention
According to a first aspect of the present invention there is provided a magnetic separator comprising a seal wherein the seal comprises a magnetic detectable material.
Preferably the seal is resilient.
Preferably the seal is an annular seal.
Preferably the magnetic detectable material comprises a ferrous material.
The magnetic detectable material may comprise iron and preferably comprises iron filings.
Preferably the seal comprises an annular seal and more preferably comprises a circular annular seal. Preferably the circular annular seal has a circular outer profile and an inner circular profile. Preferably the outer profile and the inner profile comprise concentric circles.
The seal may comprise a shaped cross sectional profile. Preferably the seal comprises a substantially "C" - shaped crossed sectional profile.
The seal may comprise an inwardly facing channel shaped cross-section.
Preferably a cross-section of the seal defines a mouth portion which is arranged to locate over and around a frame member in order for an inner surface of the seal to locate adjacent to an outer surface of the frame member.
The seal may comprise a shaped cross-sectional profile having an upper portion and a lower portion and a connecting portion located therebetween.
Preferably the connecting portion extends between first end of the upper portion and a first end of the lower portion.
Preferably the seal is arranged, in use, to locate around a frame member and preferably around an annular frame member.
Preferably the seal is arranged, in use, to locate around an outer frame member of a magnetic separator.
Preferably the seal is arranged, in use, to be retained around an outer frame member by an interference fit.
The seal may comprise a coloured material in order for fragments of the seal to be visually identifiable.
The magnetic separator may comprise an annular frame member and a plurality of magnetic rods. Preferably the magnetic separator comprises a magnetic array or a magnetic grid.
Preferably the seal comprises a static dissipative material.
Preferably the seal comprise an extruded strip which may be subsequently cut and may subsequently be bonded or otherwise secured to form an annular ring.
According to a second aspect of the present invention there is provided a seal for a magnetic separator wherein the seal comprises a magnetic detectable material.
According to a third aspect of the present invention there is provided a method of sealing a magnetic separator within separating apparatus, the method
comprising locating a seal around an outer frame member of the magnetic separator and wherein the seal comprises magnetic detectable material.
Brief Description of the Drawings
For a better understanding of the present invention and to show how the same may be carried into effect, there will now be described, by way of example only, specific embodiments, methods and processes according to the present invention with the reference to the accompanying drawings, in which:
Figure 1 is a plan view of a preferred embodiment of a seal for use in a magnetic separator.
Figure 2 is a side view of a preferred embodiment of a seal for use in a magnetic separator.
Figure 3 is a cross sectional view of a preferred embodiment of a seal for use in a magnetic separator.
Figure 4 is a plan view of a magnetic separator including a preferred embodiment of a seal.
Description of the preferred embodiments
As previously explained, magnetic separators located in separating apparatus are frequently used in the food industry including the pharmaceutical industry, for example, bakeries may use separating apparatus to extract magnetic contaminants from flour (or other ingredients) during the baking process. The uses may also include, but not limited to, the use in flourmills, bakeries, pharmaceutical production systems and chemical production systems. The separator may also help to size and break up the material and/or restrict the flow and processing of relatively large lumps of material.
The separator apparatus includes an inflow region (for example, a hopper) into which the flour is poured. The flour then passes through the magnetic separator where magnetic contaminants are extracted. The flour then flows through an outflow region into the processing apparatus. For example, 25 kg bags of flour may be poured into the hopper in order to be initially screened and cleaned prior to the baking process.
In use, material is arranged to pass through the separating apparatus in order for magnetic contaminants to be extracted from the material. In particular, the magnetic separator is for use in the food and pharmaceutical industries. Contamination such as rust, stainless steel scrapings and wear from machinery are often too small to be detected by a metal detector but is easily removed by magnetic separators.
The material flows through the magnetic grid and any contamination is immediately attracted to the powerful magnetic rods. The contamination is pushed to the undersides of the rods, where it is securely held, out of the way of the wash off effects of continuous material flow. The grid requires no power and no maintenance (except for cleaning) and is quick and easy to install. The strength of the magnetic rods can be selected for either coarse ferrous contamination or for micron sized ferrous contamination and para-magnetic contamination.
As shown in figure 4, a magnetic separator 10 comprises an annular frame member 12 and a plurality of parallel magnetic members 14. In particular, the magnetic members 14 comprise linear magnetic rods 14 which are retained in the annular frame member 12. The linear magnetic rods 14 form a magnetic array or magnetic grid. In use, the magnetic separator 10 is located in a processing system in order for the magnetic separator 10 to extract magnetic contaminants from a processing material. For example, the magnetic separator 10 may be located in
a lower end of a hopper such that the processing material is poured into the hopper and is arranged to pass through the magnetic separator 10. The magnetic rods 14 are arranged in a linear array and provide openings between adjacent magnetic rods 14 for the processing material to flow therethrough. The proximity of the processing material to the magnetic rods 14 is therefore set or controlled. The strength of extraction can be determined by the magnetic strength of the magnetic rods 14 and the separation distance of the magnetic rods 14. The strength of extraction can be set for coarse ferrous contamination and/or for micron sized ferrous contamination and/or for para-magnetic contamination.
In use, the magnetic separator 10 is vibrated in order to aid the flow of the processing material through the magnetic separator 10. In particular, the magnetic separator 10 may be driven at a relatively high frequency to oscillate the magnetic separator 10 at a high frequency. This movement can cause relatively high momentum and inertia forces in the magnetic separator 10. The vibration of the magnetic separator 10 acts to separate the material and effectively aids the sieving process.
As shown in figure 4, the seal 16 of the magnetic separator is arranged to locate around an outer frame member 12 of the magnetic separator 10. The processing apparatus comprises a securement mechanism for securing the magnetic separator 10 within the processing apparatus. The securement mechanism may comprise a clamping mechanism whereby the outer frame member 12 and the seal 16 are clamped into position within the processing apparatus. For example, the securement mechanism may comprise over centre toggle clips radially spaced around the apparatus. The seal 16 is therefore compressed, in use. The sieve plate may be changed frequently and may be changed each time as new material is used in the apparatus. Accordingly, the seal may be regularly compressed and uncompressed. As the magnetic separator 10 is vibrated, the high momentum and inertia forces are dissipated and transmitted through the seal 16.
The high forces cause the seal 16 to wear with use. The seal 16 is, therefore, prone to fatigue failure and may crack or split. Furthermore, with use, fragments of the seal 16 may be dislodged or other parts of the seal 16 may become separated from the seal. These fragments or parts will then enter the processing material and will act as a contaminant to the processing material.
The present invention provides a seal 16 of a magnetic detectable material such that any fragments can be relatively easily detected and extracted. In particular, since the seal 16 is for use around a magnetic separator 10 and the seal 16 comprises a magnetic detectable material, any contamination comprising fragments of the seal will be immediately detected and extracted by the magnetic separator 10. In addition, magnetic detection and magnetic extraction apparatus are frequently used further down the processing line from the magnetic separator 10. Such magnetic detection and magnetic extraction apparatus may further ensure that fragments of the seal are not present in the final product. Accordingly, the magnetic separator 10 may be used as an initial magnetic separator and any any missed fragments may subsequently be detected and extracted further down the processing line.
Prior art seals comprising non-magnetic detectable material pose significant health and safety and hygienic risks and this is particularly apparent in the food and pharmaceutical industries and, in particular, where the magnetic separator is the subject of high momentum and inertia forces.
As shown in figure 1 , figure 2 and figure 3, the seal 16 may comprise a circular annular member and comprises a resilient material incorporating a magnetic material. In particular, the magnetic material comprises a ferromagnetic material. In the preferred embodiment, the ferromagnetic material comprises iron and in particular, comprises iron filings. The iron filings are distributed substantially uniformly throughout the material of the seal.
The seal 16 comprises an annular member which has a substantially uniform cross section (as shown in figure 3). The seal 16 has an inner periphery which is circular and has an outer periphery which is circular. The inner periphery and the outer periphery comprise concentric circles. In particular, the seal 16 has a substantially C - shaped cross section such that the cross section comprises an upper projection 18 which locates on an upper surface of the annular frame member 12 of the magnetic separator 10, a side section 20 which locates adjacent to a side surface of the annular frame member 12 of the magnetic separator 10 and a lower projecting surface 22 which locates adjacent a lower surface of the annular frame member 12 of the magnetic separator 10.
The seal 16 is arranged to be retained to the annular frame member 12 and secured to the annular frame member 12 by an interference fit. Accordingly, in use, the seal 16 is stretched to fit over the annular frame member 12 and is then held securely in place by the interference fit.
An upper surface of the upper projecting surface 18 may comprise raised surfaces 19 or a raised pattern which may improve the sealing characteristics of the seal 16. Similarly, the lower surface of the lower projecting surface 22 may comprise a raised surface 23 or raised pattern which may improve the sealing and characteristics of the seal 16.
The seal 16 is formed from an extruded strip which is cut to the required length and then bonded to form an annular ring seal of the correct circumference/diameter.
The annular frame member 12 includes rounded corners in order to prevent piercing or otherwise damaging the seal 16.
The seal 16 comprises a resilient material and in particular comprises a resilient plastics or a rubber. The seal 16 comprises a coloured material such that the seal 16 or parts of the seal 16 are easily visually identifiable by a person
such that relatively large fragments of the seal 16 may also be identified visually by a worker and removed by the worker. In particular, the colour of the seal 16 may be selected to be prominent and contrast with the respective to the colour of the processing material. In particular, the seal 16 is blue. In addition, the processing apparatus may include a visual sensor to sense the presence of a fragment of the seal 16.
The construction of the present invention helps to provide a current pharmaceutical standard magnetic separator to be commercially available to the food industry which generally use less expensive apparatus.
In addition, in the present invention, all materials used may help to reduce static in order to allow the apparatus to possibly be used in special environments, for example "ATEX" environments. In particular, the seal 16 may comprise a static dissipative material.
The present invention thereby provides a magnetic separator with increased reliability with respect to prior art magnetic separators.
The present invention also provides a magnetic separator which does not include small parts which can be misplaced, lost or inadvertently separated.
The present invention may also help to provide a magnetic separator which is particularly for use in explosive atmospheres in the work place caused by flammable gases, mists or vapours or by combustible dusts. In particular, the present invention may be designed for use in accordance with the DSEAR and ATEX framework for controlling explosive atmospheres and the standard of equipment and protective systems used therein.