INSULATING JACKET FOR A FILTER

Abstract

An insulating cover for a central heating system filter is provided in two parts. The insulating cover may be made from, for example, expanded polypropylene foam. The cover may include magnets for attracting and retaining magnetic debris within the filter. The cover may include a leadscrew arrangement to assist with removal of the cover from the filter for servicing.

Claims

1. An insulating cover for a central heating system filter, the insulating cover being made from a resilient insulating material, and being provided in two parts, the two parts of the cover being releasably attachable to each other by resilient clips, and the two parts of the cover substantially surrounding at least part of the filter, and being retained around the filter, when the two parts of the cover are attached to each other by the clips, and the cover being removable from the filter by releasing the attachment of the two parts of the cover to each other, in which an arrangement of magnets is provided on an inside surface of the cover, the magnets facing towards the filter when the cover is installed on the filter.

2. The insulating cover as claimed in claim 1, in which the magnets are arranged in one or more pairs, each magnet being in the form of a substantially cylindrical billet, and the magnets of each pair being joined together by a ferromagnetic carrier.

3. The insulating cover as claimed in claim 2, in which the magnets are mounted on springs which urge the magnets towards the filter in use.

4. The insulating cover as claimed in claim 3, in which a force transfer element is provided to a side of the carrier facing towards the filter in use, the force transfer element being arranged to push the magnets away from the filter when the cover is removed from the filter.

5. The insulating cover as claimed in claim 4, in which the force transfer element is fixed to the cover by at least two screws.

6. The insulating cover as claimed in claim 5, in which an apertured plate is provided on the side of the cover facing away from the filter, the screws fixing the force transfer element to the cover passing through the apertures in the plate.

7. The insulating cover as claimed in claim 1, in which the clips are integrally formed as part of the cover.

8. The insulating cover as claimed in claim 1, in which each clip is formed as an extension from a face of one of the two parts of the insulating cover, the extension becoming wider as it extends away from the face to form a lip at a distal end of the extension.

9. The insulating cover as claimed in claim 8, in which the other of the two parts includes a recess in a face, the recess corresponding to a shape of the clip, and the recess including an undercut corresponding to the lip of the clip.

10. The insulating cover as claimed in claim 1, in which a leadscrew arrangement is provided on each part of the two-part cover, for levering the cover away from the filter.

11. The insulating cover as claimed in claim 1, in combination with a filter for a heating system, the filter including an internal magnet.

12. An insulating cover for a central heating system filter, the insulating cover being made from a resilient insulating material, and being provided in two parts, the two parts of the cover being releasably attachable to each other by resilient clips, and the two parts of the cover substantially surrounding at least part of the filter, and being retained around the filter, when the two parts of the cover are attached to each other by the clips, and the cover being removable from the filter by releasing the attachment of the two parts of the cover to each other, in which a leadscrew arrangement is provided on each part of the two-part cover, for levering the cover away from the filter.

13. The insulating cover as claimed in claim 12, in which the leadscrew arrangement includes a plate having a female-threaded aperture, provided on a side of the cover facing towards the filter.

14. The insulating cover as claimed in claim 12, in which an elastomeric cap is provided over an end of the leadscrew.

15. The insulating cover as claimed in claim 12, in combination with a filter for a heating system, the filter including an internal magnet.

16. An insulating cover for a central heating system filter, the insulating cover being made from a resilient insulating material, and being provided in two parts, the two parts of the cover being releasably attachable to each other by resilient clips, the clips being integrally formed as part of the cover, and the two parts of the cover substantially surrounding at least part of the filter, and being retained around the filter, when the two parts of the cover are attached to each other by the clips, and the cover being removable from the filter by releasing the attachment of the two parts of the cover to each other.

17. The insulating cover as claimed in claim 16, in which the insulating material is expanded polystyrene or expanded polypropylene foam.

18. An insulating cover for a central heating system filter, the insulating cover being made from a resilient insulating material, and being provided in two parts, the two parts of the cover being releasably attachable to each other by resilient clips, and the two parts of the cover substantially surrounding at least part of the filter, and being retained around the filter, when the two parts of the cover are attached to each other by the clips, and the cover being removable from the filter by releasing the attachment of the two parts of the cover to each other, in which each clip is formed as an extension from a face of one of the two parts of the insulating cover, the extension becoming wider as it extends away from the face to form a lip at a distal end of the extension.

19. The insulating cover as claimed in claim 18, in which the other of the two parts includes a recess in a face, the recess corresponding to a shape of the clip, and the recess including an undercut corresponding to the lip of the clip.

20. The insulating cover as claimed in claim 18, in which the two parts of the insulating cover are substantially identical to each other.

Description

DESCRIPTION OF THE DRAWINGS

[0025] For a better understanding of the present invention and to show more clearly how it may be carried into effect, embodiments will now be described by way of example only with reference to the accompanying drawings, in which:

[0026] FIG. 1 shows a filter for a central heating system and an insulating cover according to the invention, ready for installation on the filter;

[0027] FIG. 2 shows the filter and insulating cover of FIG. 1, with the cover installed on the filter;

[0028] FIG. 3 shows the filter and insulating cover of FIG. 2, when the cover is in the process of being removed from the filter to allow cleaning; and

[0029] FIG. 4 is an exploded view of the insulating cover.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] Referring firstly to FIG. 1, a filter for a heating system is indicated at 100. In this case, the filter already contains an internal magnet to capture magnetite within the filter, but equally the insulating cover of the invention could be used with a non-magnetic filter, e.g. a filter having a mesh or gauze, or using for example a hydrocyclone separator.

[0031] An embodiment of an insulating cover according to the invention is provided in two parts, each part indicated at 10. In this embodiment, each of the two parts is in fact identical. As shown in FIG. 1, one part may be rotated 180 with respect to the other part, for the parts to fit together. In particular each part 10 comprises a substantially half-cylindrical shell having a curved internal cylindrical surface 12 and a curved external cylindrical surface 14, and a flat face 16 corresponding to a plane bisecting (what would be) the cylindrical shell. The parts 10 are made from expanded polypropylene. This is a durable and slightly resilient rigid foam material with good thermal insulation properties.

[0032] The flat face 16 is roughly “U” shaped. Along one “arm” of the “U” a series of resilient clips 16, 18, 20, 22 in the form of protrusions are provided. Each of the resilient clips is formed integrally with the expanded polypropylene cover 10. Each of the resilient clips extends away from the flat face 16, and widens out as it extends further away from the flat face 16. A lip is therefore formed at a distal end of each resilient clip. Each of the resilient clips is disposed adjacent an edge of the flat face, and adjacent clips are disposed adjacent alternate edges. In particular, clips 16 and 20 are disposed adjacent an inner edge of the flat face 16, i.e. an edge of the flat face 16 which is adjacent the internal cylindrical surface 12, and clips 18 and 22 are disposed adjacent an outer edge of the flat face 16, i.e. an edge of the flat face 16 which is adjacent the external cylindrical surface 14. On the clips disposed adjacent the inner edge, the lip faces primarily towards the outer edge, and on the clips disposed adjacent the outer edge, the lip faces primarily towards the inner edge.

[0033] On the other “arm” of the “U” shaped flat face 16, recesses/sockets 24, 26, 28, 30 are provided corresponding to the shape of the clips 16, 18, 20, 22. Each recess extends into the flat face 16 and widens as it extends deeper, to form an undercut corresponding to the lip of a corresponding resilient clip.

[0034] In this embodiment, the two parts 10 of the cover are exactly identical. In FIG. 1 the clips and corresponding recesses are visible on the part which is top-right of the drawing, and not visible on the part which is bottom-left, due to the orientation. However, it will be understood that the clips of each part interface with the recesses of the other part.

[0035] When the parts 10 of the cover are pushed together around a filter 100, the clips 16, 18, 20, 22 deform slightly until the lip of each clip is in a respective undercut of a recess. The clips then return to their previous shape and act to hold the two parts 10 firmly together, as shown in FIG. 2.

[0036] The cover includes a bottom wall 32 which substantially covers the bottom of the filter 100. The top of the filter is where inlet and outlet pipes are connected and so space needs to be left for valves and other parts to be connected. The cylindrical filter 100 has a flanged section 102 just below the inlet and outlet fittings 104, 106. An extension 34 from the top of each part of the cover includes an interior circumferential slot which corresponds to the position of the flange 102 of the filter when the cover is fitted. This prevents the cover from moving axially in relation to the filter, i.e. prevents the cover from falling off the filter 100 in a downwards direction as shown in the drawings, when the cover is fitted on the filter.

[0037] Magnets 36 are disposed on the internal cylindrical surface 12 of each part 10 of the cover. When the cover is fitted to the filter 100, the magnets 36 face towards the outside wall of the filter 100. Magnetic debris which flows through the filter is attracted by the magnets and is held against the interior of the wall of the filter 100. In this case, the filter 100 also has a magnet inside and so the effect of installing the cover is not only to insulate the filter but to improve the magnetic capture performance of the filter. In other cases the filter may not have an internal magnet and therefore the cover may be used to provide magnetic capture capability where there was previously none.

[0038] When the filter needs to be cleaned, the cover will need to be taken off, allowing captured magnetic debris to fall away from the interior of the filter wall to be drained out. However, there will be significant magnetic attraction between the magnets 36 and the captured magnetic debris inside the filter. In an embodiment with a stainless steel filter of height around 370 mm with 2 mm thick walls, the force required for removal may be equivalent to about 5 kg. Also, if the force is applied unevenly or to weak parts of the cover, there is a risk that the expanded polypropylene material may be damaged. Therefore, a leadscrew arrangement is provided to assist with removing the cover from the filter.

[0039] One each part 10 of the cover, two leadscrews 38, 40 are provided. Each leadscrew is disposed substantially centrally between the two arms of the “U” shaped flat face 16, and extends through an aperture in the cylindrical shell running from the external cylindrical surface 14 to the internal cylindrical surface 12. One leadscrew 38 is close to the top of the cover and one leadscrew 40 is close to the bottom of the cover. A plate 42, 44 with a female threaded bore is provided on the interior side of the cover, corresponding to each leadscrew 38, 40. Hence the screw can be rotated to extend it towards and against the outer surface of the filter 100, levering the cover away from the filter.

[0040] FIG. 3 shows the cover in the process of being removed. By operating the leadscrews one at a time, the cover is slowly levered away from the filter, and a consistent force is applied via the plates 42, 44, at a central point between the two arms of the “U” shaped flat face. This flexes the resilient clips 16, 18, 20, 22 without damaging them, and overcomes the magnetic attraction between the magnets 36 and magnetic debris captured inside the filter 100.

[0041] With reference to FIG. 4, the arrangement of the magnets 36 will now be described in more detail. The magnets 36 are fixed to ferromagnetic carriers 46 in pairs. I.e. on each ferromagnetic carrier there are two magnets 36. Each magnet 36 is in the form of a substantially cylindrical billet with north and south poles on the opposing circular surfaces of the cylindrical billets. The pair of magnets 36 on a single carrier 38 is arranged so that the north pole of one magnet is against the carrier, and the south pole of the other magnet is against the carrier. This tends to focus the magnetic field lines out of the billets on the side facing away from the carrier, which is into the filter when the cover is fitted.

[0042] A leaf spring 48 is disposed behind each carrier 46, for urging the carrier 46 and attached magnets towards the surface of the filter.

[0043] A force transfer element 50 is provided in the form of a rigid plastic bar which is fixed in front of (i.e. on the interior side of) each carrier 46, between the two magnets 36. The force transfer element is rigidly fixed to the cover 10 by screws. Therefore, when the cover is levered away from the filter, the force transfer elements push against the magnets from the interior side. There does not need to be any “pulling” of the magnets from the exterior side and this means that the spring 48 can be designed without the requirement of high strength under extension.

[0044] The force transfer element 50 also provides a pivot on which the carrier 46 may rotate slightly. The pivot is located offset from the central point between the two magnets 36 so that each carrier will tend to rotate in a particular direction. The force transfer elements 50 on the right hand side of FIG. 4 have the pivot offset towards the bottom of the drawing, so the lower magnet 36 in each right-hand pair will tend to detach from the filter surface before the corresponding upper magnet. The force transfer elements 50 on the left hand side of FIG. 4 are the same component, but are oriented so that the pivot is offset towards the top of the drawing, so the upper magnet 36 in each left-hand pair will tend to detach from the filter surface, when the cover is removed, before the corresponding lower magnet.

[0045] Where the magnets are fixed to the cover, the cover is provided with formations to receive the magnets and house the various parts of the arrangement. Apertures are provided through the cover for screws 52 to pass through. However, the expanded polypropylene material used to form the cover 10 is relatively soft and does not provide a good reaction surface for the head of the screw. Therefore a plate washer 54 is provided, made for example from thin stainless steel. A plate washer 54 is provided corresponding to each force transfer element 50, and has apertures for two screws 52. The plate washer 54 spreads the load over a wider area of the polypropylene cover. Hence the magnets 36, carrier 46 and spring 48 is clamped between the cover 10 and the force transfer element 50. The force transfer element 50 is attached to the cover by the screws 52 and plate washer 54.

[0046] An expanded polypropylene cap 56 covers the heads of screws 52, which in normal use and servicing do not need to be accessed.

[0047] The cover of the invention provides an insulating jacket for a filter, whether this is a filter which already has magnetic capture capability, in which case the extra magnets 36 serve to improve the magnetic capture performance of the filter, or a filter which by itself captures debris purely by non-magnetic means (e.g. a mesh, gauze, cyclone or other separation means), in which case the magnets 36 add magnetic capture capability to the filter. The insulating cover is easily removable when the filter needs to be cleaned out. The cover also provides the possibility of retro-fitting magnetic capture capability to a heating system at low cost.

[0048] It will be understood that the variations and modifications to the embodiment described may be envisaged, within the scope of the claims.