Magnetic filter

Abstract

A magnetic filter suitable for use in large heating and / or cooling systems, such as heating systems using piping systems between 2-inch and 4-inch bores, is disclosed. The magnetic filter includes a tubular separation chamber and an externally mounted magnetic assembly that is movable from a position proximate to the pipe to a position spaced from the pipe. The magnetic assembly is pivotally mounted to the pipe by a frame.

Description

[0001] Divisional application

[0002] This application is a divisional application of application number 2018107915387, filing date July 18, 2018, and titled “Magnetic Filter”. Technical Field

[0003] The present invention relates to a magnetic filter, in particular to a magnetic filter suitable for use in large commercial central heating or cooling systems. Background Art

[0004] It is now common to install magnetic filters in wet central heating systems. Magnetic filters improve the performance of the system by attracting and retaining magnetic particles, removing them from the system water to prevent them from damaging heat exchangers, pumps and other components that are susceptible to damage by particles within the heating fluid. These magnetic filters can also be used in other types of closed loop water systems, including refrigeration systems and chillers.

[0005] For domestic central heating systems, a chamber-shaped (usually made of plastic) magnetic filter is usually provided, the chamber having an inlet and an outlet and a magnet inside the chamber. An example of such a magnetic filter is disclosed in GB 2491246. This type of filter is usually available in 22 mm and 28 mm sizes, which are the most common pipe hole sizes in domestic central heating systems.

[0006] Larger systems, such as those used in commercial buildings, typically employ 2 inch (about 50 mm) or larger diameter pipes. These larger systems may use filters such as those sold by the applicant under the trademark "Magnaclean (RTM) Commercial". These filters take the form of large, heavy cast containers that include an inlet or outlet on two sides, a removable cover, and a magnet extending into the chamber. However, these filters are expensive to manufacture and lower cost alternatives are needed.

[0007] "Large systems" include 2", 2.5", 3", 4", 6" and 8" tube openings. Therefore, many different filter sizes need to be provided to cover the range of large heating systems, which further increases the cost of the product.

[0008] It has been proposed in GB2551828 to manufacture a tubular filter having an inlet and an outlet section and a filter section of wider diameter between the inlet and the outlet. The magnetic element is arranged outside the tube around the filter section. However, manufacturing tolerances can prevent good contact of the magnets, resulting in suboptimal magnet performance. Furthermore, manufacturing a tube filter section with a flat section is expensive.

[0009] When magnetic debris accumulates within the filter, there is a force pushing the magnetic element towards the filter body. Cleaning the filter can be difficult because the magnetic element must be removed away from the filter body against this force. Threads were envisioned in GB2551828 to provide a mechanical advantage and make this possible, but this means that the process of removing the magnetic element away from the filter body is time consuming.

[0010] The object of the present invention is to solve the above-mentioned problems. Summary of the invention

[0011] According to a first aspect of the present invention, there is provided a magnetic filter for a central heating and / or cooling system, the magnetic filter comprising a chamber and a movable magnetic assembly, the chamber having an inlet and an outlet, the movable magnetic assembly being adapted to move from a position close to an outer wall of the chamber to a position separated from the outer wall of the chamber; the movable magnetic assembly comprising an elongated bracket and a plurality of magnet pairs, the elongated bracket having a longitudinal centerline, the plurality of magnet pairs being arranged along the bracket; each magnet pair having a first magnet on one side of the centerline and a second magnet on the other side of the centerline, the first and second magnets of each magnet pair being connected to each other by a rod passing through the centerline, and the rod being movable relative to the bracket on a pivot; wherein a pivot corresponding to at least one of the magnet pairs is offset from the centerline to one side, and a pivot corresponding to at least another of the magnet pairs is offset from the centerline to the other side.

[0012] In a configuration where the magnetic assembly is positioned close to the outer wall of the chamber, the magnet is preferably in contact with the outer wall of the chamber. In a configuration where the magnetic assembly is spaced apart from the chamber, the magnet may be, for example, a few centimeters from the chamber wall. Only a short spacing is required to significantly reduce the magnetic attraction between the magnet and the magnetic particles within the chamber to allow the captured magnetic debris to drain.

[0013] A drain port may be provided in the chamber.

[0014] In use, the magnetic assembly is positioned near or against the outer wall of the chamber. During operation of the system, central heating / cooling system water flows through the chamber and any magnetic particles that may be entrained in the system water are attracted to the magnets and held within the chamber against the walls of the chamber. At some point, it will be necessary to remove the magnetic debris. This can be accomplished by isolating the filter from the heating / cooling circuit, moving the magnetic assembly to a position spaced apart from the chamber, and then opening a drain in the chamber to drain the fluid and magnetic particles out of the chamber. It may sometimes be preferred to reconnect one of the inlet and outlet to the central heating / cooling circuit for a short period of time while the drain remains open to flush the filter and remove any other debris.

[0015] Ideally, the filter inlet and outlet are connected to the system loop via valves, making the isolation and reconnection process very simple. This can be arranged using readily available off-the-shelf valve components and appropriate fittings to match the filter and system loop.

[0016] The magnetic assembly with magnet pairs has pivots offset to different sides to assist when the magnetic assembly must be moved away from the filter body for cleaning. When force is applied to pull the magnetic assembly away from the chamber, the magnet pairs will pivot so that one magnet in each pair is slightly away from the filter body ahead of the other magnet in the pair. This makes it easier to overcome the magnetic attraction between the magnets and magnetic debris captured within the filter.

[0017] Preferably, all pivots are offset. More preferably, approximately half of the pivots are offset to one side and approximately half of the pivots are offset to the other side. Where the total number of pivots on the carriage is an even number, it may be possible and desirable for exactly half of the pivots to be offset to one side and exactly half of the pivots to be offset to the other side. Where the total number of pivots is an odd number, the number of pivots offset to each side will not be exactly equal. Preferably, the offset of the pivots alternates along the magnetic assembly. In this way, as the magnetic assembly is pulled away from the chamber, the force caused by the magnetic attraction between the magnets near the chamber wall and the debris within the chamber will decrease in a relatively uniform manner along the magnetic assembly.

[0018] Preferably, the magnet pair is spring loaded towards the chamber. To achieve this, a spring may be provided between the magnet pair and a portion of the bracket structure extending behind the magnet pair, ie, on a side of the magnet pair facing away from the chamber in use.

[0019] The spring ensures good, tight contact between the magnet and the outer wall of the chamber, even if the surface contour of the chamber wall may be imperfect.

[0020] Preferably, the carriage comprises a force transfer element arranged between the rod of the magnet pair and the chamber wall, the force transfer element being rigidly attached to the rest of the carriage. The force transfer element moves the magnet away from the chamber by applying a force to the front of the rod and therefore to the magnet pair, i.e. pushing the magnet pair from the side facing the chamber. This avoids loading the spring when pulling the carriage away from the chamber. Therefore, the springs used can be thin leaf springs, as they never bear large loads. The only purpose of the spring is to push the magnet towards the chamber wall in use and ensure good contact.

[0021] The centerline of the bracket is the center because it is substantially centered between the two magnets of each magnet pair. It may not be the center relative to the overall structure of the bracket. In fact, some embodiments may have two or more rows of magnet pairs, and thus two or more centerlines on a single magnetic assembly.

[0022] The chamber may be generally cylindrical, with a curved outer wall. In this case, the magnetic assembly is preferably curved and arranged around the curved outer wall of the chamber when in a position close to the chamber. In this case, the centerline of the bracket is curved, preferably in the shape of an arc of a circle.

[0023] Preferably, the magnetic filter comprises a plurality of magnetic assemblies, each magnetic assembly being individually movable between a position proximate to the chamber and a position spaced apart from the chamber. In one embodiment, each magnetic assembly is substantially semicircular. Two semicircular assemblies may be provided, extending from the same pivot in opposite directions. When in a position proximate to the chamber, the two semicircular assemblies may substantially form a full circle. The two semicircular assemblies may surround and encircle the chamber.

[0024] Preferably, the magnetic assembly is spring loaded into a position spaced from the chamber and may be held against the spring by the retaining means when the assembly is in a position proximate the chamber.

[0025] In a preferred embodiment, each assembly is connected to the filter body by a pivot at one end of the bracket. When in a position close to the filter chamber, the assembly is held at the other end of the bracket against the action of the spring. Preferably, the spring loading is achieved by a torsion spring at the pivot point.

[0026] A stop may be provided to limit the extent to which the magnetic assembly may be moved away from the chamber. In the event that the assembly moves by pivoting from one end of a bracket, the stop may be provided in the form of an extension of the bracket extending from the pivot point in a direction opposite to the greater length of the bracket. As the bracket moves away from the chamber on the pivot, the stop will move toward the chamber until it contacts the chamber, thereby preventing further movement of the bracket. The stop, in combination with a torsion spring on the pivot, provides an easy to use magnetic assembly that reliably moves to a position spaced apart from the chamber. Because the assembly is magnetic, and because embodiments may include multiple magnetic assemblies, and because there may be significant magnetic attraction to debris within the filter, unrestricted movement of the bracket may be problematic and unsafe.

[0027] According to a second aspect of the present invention, there is provided a magnetic filter for a central heating and / or cooling system, the magnetic filter comprising a chamber having an inlet and an outlet and an elongated magnetic assembly,

[0028] The elongated magnetic assembly is mounted outside the chamber on a pivot, the pivot being disposed near one end of the elongated magnetic assembly, and a major length of the elongated magnetic assembly can be moved from a position proximate to the chamber to a position spaced apart from the chamber by pivoting the magnetic assembly on the pivot,

[0029] The secondary length of the elongated magnetic assembly extends from the pivot point in a direction opposite to the primary length, and when the primary length of the elongated magnetic assembly is spaced apart from the chamber, the secondary length forms a stop for contacting the chamber to prevent the primary length of the magnetic assembly from moving further away from the chamber.

[0030] Preferably, the magnetic assembly may be spring loaded to a position where the main length is spaced apart from the chamber. In one embodiment, the spring loading is provided by a torsion spring at the pivot point.

[0031] Embodiments of the second aspect of the present invention may also share features of embodiments of the first, third and fourth aspects of the present invention.

[0032] According to a third aspect of the present invention, there is provided a magnetic filter for a central heating and / or cooling system, the magnetic filter comprising a chamber having an inlet and an outlet and a magnetic assembly, the magnetic assembly being mounted outside the chamber and being movable from a position close to an outer wall of the chamber to a position spaced from the outer wall of the chamber,

[0033] The magnetic assembly comprises:

[0034] bracket;

[0035] at least one magnetic element mounted to the bracket on a side of the bracket facing the chamber;

[0036] at least one spring disposed between the bracket and the magnetic element for urging the magnetic element toward the chamber; and

[0037] At least one force transfer element, rigidly fixed to the bracket and arranged in front of the magnetic element or a part of each magnetic element, is used to push the magnetic element from the side of the magnetic element facing the chamber when the magnetic assembly is moved to a position separated from the outer wall of the chamber to apply force to the magnetic element in a direction away from the chamber.

[0038] Preferably, the spring is a leaf spring. In one embodiment, the spring has a hole on the side of the spring facing the chamber, and the protrusion in the rear of the magnetic element is located in the hole. The magnetic element can be in the form of a pair of magnets connected by a rod. The force transfer element can extend between the two magnets in front of the rod (i.e., on the side facing the chamber). In this way, the force transfer element can push the magnetic element from the side facing the chamber, but at the same time the magnet itself is not hindered by the force transfer element, so when the magnetic assembly is in a position close to the chamber, it can be arranged very close to the outer wall of the chamber, preferably in contact with the outer wall of the chamber.

[0039] The embodiments of the third aspect of the present invention may also share features of the embodiments of the first, second and fourth aspects of the present invention.

[0040] According to a fourth aspect of the present invention, there is provided a magnetic filter for a central heating and / or cooling system, the magnetic filter comprising:

[0041] a chamber which is substantially in the form of a cylindrical tube having an inlet and an outlet at either end of the tube;

[0042] a frame fixed to the outside of the tube, the frame comprising rods extending along the outside of the tube, the rods being substantially parallel to the tube;

[0043] At least one elongated curved magnetic assembly having a rod pivotally mounted on a pivot disposed proximate one end of the magnetic assembly, wherein the major length of the elongated magnetic assembly can be moved from a position proximate the chamber to a position spaced apart from the chamber by pivoting the magnetic assembly on the pivot.

[0044] In most embodiments, it is contemplated that a plurality of pivotable magnetic assemblies are disposed along a rod. The magnetic assemblies may include holes. To assemble the magnetic filter, a single rod may be passed through the holes in the plurality of magnetic assemblies, and the rod may then be secured to the rest of the frame and thus to the magnetic filter.

[0045] Advantageously, magnetic filters of different sizes can be assembled from a small number of different parts from stock. It is conceivable that a magnetic filter suitable for a heating / cooling system with a 2 inch to 4 inch bore could use a tubular chamber of the same diameter, with only the inlet and outlet and associated connections different for use with the different size systems. Larger systems will have greater flow rates through the filter, and more magnetic elements will be required to ensure effective capture performance. However, all frames and magnetic components are universal across a range of sizes, except that a variety of different lengths of rods may be provided. Because the magnetic filters are assembled in a modular manner, assembling the filter for a larger system simply involves mounting a greater number of magnetic components to the rods.

[0046] For example, for all variants, the outer diameter of the separation chamber can be six inches, suitable for systems with 2-inch, 2.5-inch, 3-inch or 4-inch holes. The filter for a 2-inch or 2.5-inch system can have, for example, three magnetic assemblies or three pairs of magnetic assemblies mounted to the frame. The filter for a 3-inch system can have four magnetic assemblies or four pairs of magnetic assemblies, and the filter for a 4-inch system can have five magnetic assemblies or five pairs of magnetic assemblies. In all cases, the separation chamber is the same, and the structure of the magnetic assemblies is the same. The construction of the frame differs only in the length of the bar. The rod is a very simple component that is inexpensive to manufacture.

[0047] Thus, to manufacture a series of four different filters, the inventory of different components and the tooling costs associated with manufacturing are reduced to a minimum.

[0048] The embodiments of the fourth aspect of the present invention may also share features of the embodiments of the first, second and third aspects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to better understand the present invention, and to more clearly show how it may be carried into effect, preferred embodiments will now be described with reference to the accompanying drawings, in which:

[0050] Figure 1 is a perspective view of a magnetic filter according to the present invention having a plurality of magnetic assemblies, all of which are shown in a closed position adjacent to a filter body;

[0051] Figure 2 It passes through Figure 1 A cross-section of a magnetic filter having a single magnetic assembly mounted and shown engaged in an open position spaced from a filter body;

[0052] Figure 3 yes Figure 1 Another perspective view of a magnetic filter having two magnetic assemblies, both shown engaged in an open position spaced apart from a body of the filter;

[0053] Figure 4 is a cross section through the magnetic component, forming Figure 1 A portion of a magnetic filter;

[0054] Figure 5 is a perspective view showing details of a partially assembled magnetic assembly, which forms Figure 1 A portion of a magnetic filter; and

[0055] Figure 6 It is shown Figure 5 FIG. 2 is a perspective view of another detail of the magnetic assembly, particularly the pivot point of the magnetic assembly. DETAILED DESCRIPTION

[0056] First reference Figure 1 , the magnetic filter is generally indicated at 10. The magnetic filter 10 includes a separation chamber 16 in the form of a cylindrical tube. The tube diameter is about 6 inches (15.24 cm). The separation chamber includes an inlet interface 12, which is in the form of an opening and a flange, and an outlet interface 14, which is in the form of a similar opening and a flange. The inlet and outlet in this embodiment are substantially the same and interchangeable.

[0057] It is contemplated that multiple versions of the filter may be produced for use in different heating or cooling systems. For example, a piping system having 2-inch, 2.5-inch, 3-inch or 4-inch holes. In each case, the inlet and outlet interfaces would include flanges and openings of appropriate size. However, the same separation chamber may be used for all variants, with only the inlet and outlet on the end being modified.

[0058] The magnetic filter includes an automatic vent 18 for exhausting air from the filter 10. As an alternative, a manual vent valve may be included. A drain port (not visible in the figure) may also be provided in some embodiments.

[0059] Best as Figure 3 As shown, a frame is provided outside the separation chamber 16. The frame comprises two two-piece clamps 20a, 20b. Each two-piece clamp has two generally semicircular parts that can be fixed to each other and tightened with screws to substantially fix the clamp around the periphery of the separation chamber 16. The two parts of the clamp can be substantially identical in form so that four identical parts are used to manufacture the two two-piece clamps of the filter.

[0060] The frame also includes a pair of rods 22a, 22b. The rods extend along the outside of the separation chamber 16, slightly spaced from the outer surface of the separation chamber, and are held in place by clamps 20a, 20b. Figure 2 As seen in cross-section in Figure 1, the rods are positioned at opposite points around the circumference of the separation chamber 16. The rods 22a, 22b can be held in place on the clamps 20a, 20b by, for example, screws passing through the clamps and into threaded holes on either end of each rod 22a, 22b, or by blind holes in the clamps that receive the ends of the rods so that the rods are held between the two clamps as long as the clamps remain fixed in place on the separation chamber 16.

[0061] A plurality of magnetic assemblies 24 are attached to the magnetic filter 10 via the frames 20, 22. Each magnetic assembly can be positioned adjacent to the separation chamber 16 ( Figure 1 All magnetic components in the separation chamber 16 are moved separately to a position separated from the separation chamber 16 ( Figure 2 and Figure 3 ). Figure 2 The manner in which the magnetic assembly attaches to and interacts with the filter 10 is best shown in FIG.

[0062] Note that Figure 2 In the embodiment, only a single magnetic assembly is shown for clarity. However, it is contemplated that most embodiments will have multiple magnetic assemblies. All multiple magnetic assemblies in this embodiment are identical.

[0063] Figure 2 and Figure 3 A partially assembled filter is shown. It is envisaged that the space between the clamps 20a, 20b will always be filled with magnetic assemblies, and that the magnetic assemblies will be arranged in pairs to completely surround the separation chamber. In the case of smaller heating systems requiring a smaller number of magnetic assemblies, the space between the clamps 20a, 20b will be reduced.

[0064] The magnetic assembly 24 includes a curved elongated bracket 25. The shape of the magnetic assembly 24 is substantially semicircular to match the contour of the outer surface of the separation chamber 16. A hole 26 is provided through the bracket 25, which is near one end of the bracket. The magnetic assembly 24 is mounted to the frame by passing one of the rods 22b of the frame through the hole. The magnetic assembly 24 can then be moved from a position close to / against the separation chamber 16 on the rod 22b. Figure 1 ) is pivoted to a position spaced apart from the separation chamber 16 ( Figure 2 ).

[0065] At the end of the bracket 25 opposite the hole 26, a resilient clip 28 is provided. The resilient clip 28 extends from the end of the bracket 25 as a blade terminating in a snap. Preferably, the resilient clip 28 is integrally formed with the rest of the bracket made of a resilient plastic material. The blade of the resilient clip 28 extends between the separation chamber 16 and the rod 22a, and the snap of the resilient clip 28 holds the bracket 25 in the closed position (see Figure 1 To release the bracket 25 and move it to an open position spaced from the bracket, the resilient clip 28 can be pushed toward the separation chamber 16 so that the catch moves away from the rod and the clamp can be released.

[0066] In this embodiment, the width of the buckle 28 (in Figure 2 The width of the bracket 25 is about half the width of the rest of the bracket 25 (in the direction of entering / passing out of the drawing - along the length of the filter 10), or just less than half the width. There is also a half-width section at the other end of the bracket 25 in which the hole 26 is provided. This allows the two brackets 24 to be fixed to the rod 22b and maintained in the closed position by the rod 22a, in the same axial position along the filter 10. The two semicircular brackets are combined together around essentially the circumference of the entire filter. It is best if Figure 3 shown.

[0067] At the end of the bracket 25 having the hole 26, a small portion of the bracket 25 is located on the opposite side of the pivot relative to the large portion of the bracket 25. This small portion (30, Figure 2 When the bracket 25 is pivoted to the open position, the majority of the bracket 25 is spaced apart from the separation chamber 16, and the stopper 30 moves toward the separation chamber 16 until the stopper 30 contacts the separation chamber 16. At this point, the majority of the bracket 25 cannot move away from the separation chamber 16 because the stopper 30 prevents further pivoting.

[0068] A torsion spring 32 is provided at the pivot for biasing the bracket 25 to the open position. Preferably, the torsion spring 32 is strong enough to keep the bracket 24 in the open position regardless of the orientation of the filter. For example, if the orientation of the filter is Figure 2If the positions shown are 90 or 180 degrees, the torsion spring 32 will resist gravity and the bracket is held in the open position. When the bracket 24 is in the closed position, the resilient clip 28 holds the bracket in the closed position to prevent the spring from moving the bracket to the open position.

[0069] The torsion spring 32 is in the form of a coil wound on the rod 22b (in practice, the coil is pre-wound during assembly and slides on the rod 22b), with two arms extending from the coil. The arms are in contact with the outer surface of the separation chamber 16 on the one hand and with the side of the bracket 25 facing the separation chamber on the other hand. Figure 6 As shown, the bracket 25 may include a formation 36 for supporting the arm of the spring 32 .

[0070] Arranging the brackets on the frame allows filters of different sizes to be made from a small number of different parts in stock. In order to make filters suitable for 2-inch, 2.5-inch, 3-inch or 4-inch systems, a tubular common separation chamber with a diameter of about 6 inches can be used. Although spaced at different distances when installed in the separation chamber, it depends on the number of brackets to be installed, the two-piece clamps forming the frame are the same for filters of all sizes. The rods forming the rest of the frame will need to be set to different lengths, but these are simple components. The brackets are the same, and only the number of brackets changes to match the filters suitable for different size systems.

[0071] Reference now Figure 4 and Figure 5 , the arrangement of the magnetic assembly 24 will be described in more detail. The main structure of the magnetic assembly is a bracket 25 made of a slightly elastic plastic material. Figure 5 The magnetic assembly 24 shown in FIG. 1 is partially assembled and can be seen toward the side of the separation chamber 16 when the magnetic assembly 24 is assembled to the filter 10. The bracket 25 includes a plurality of grooves for receiving the magnet pairs. Figure 5 There are two fully visible grooves and one partially visible groove on the right side of the picture. Figure 2 As shown, there are a total of four recesses in each magnet assembly 24 for receiving magnet pairs.

[0072] Each groove in the bracket extends substantially across the width of the bracket and has open sides. A rod-shaped force transmission element 38 passes through substantially the center of the groove in the length direction of the bracket. The force transmission element 38 is formed integrally with the bracket 25. There is a space between the force transmission element 38 and the back side of the bracket (the back side is the side of the bracket facing away from the separation chamber when assembled).

[0073] The leaf spring 40 passes between the force transmission element 38 and the back of the spring. The leaf spring 40 has two leaves, one on each side of the force transmission element 38 when installed. Each leaf has a through hole 42. Figure 5 is shown in a stereogram in Figure 4 Shown in cross section.

[0074] The magnet pair 44 is then installed and held between the spring 42 and the force transfer element 38. Figure 5 In the left hand side, the groove has a spring 42 and a magnet pair 44. The groove on the right hand side is only partially completed, so the spring 42 is visible.

[0075] The magnet pair 44 includes a pair of substantially cylindrical billets 46a, 46b. Each billet has a north pole at one end of the cylinder and a south pole at the other end of the cylinder. The billets are assembled onto a ferromagnetic rod 48 with the north pole of one billet and the south pole of the other billet in contact with the rod 48. The billets 46a, 46b and the ferromagnetic rod 48 together act as a horseshoe magnet.

[0076] The magnet blanks 46a, 46b can be fixed to the rod by bolts 50. Nuts 52, preferably rivet nuts, can be provided on the other side of the rod to receive the bolts. The nuts 52 can be conveniently positioned in the holes 42 by the blades of the spring 40.

[0077] When assembling, it is best to Figure 4 As shown, the force transmission element 38 integral with the bracket 25 extends substantially perpendicularly to and in front of the ferromagnetic rod 48. The ferromagnetic rod 48 is located between the force transmission element 38 and the spring 40. The spring 40 pushes the magnet pair 44 toward the separation chamber. The force transmission element 38 extends between the two magnetic blanks 46a, 46b, so that although the force transmission element 38 acts on the magnet pair 44 through the ferromagnetic rod 48, it does not hinder the magnetic blanks 46a, 46b. With the magnetic assembly 24 in the closed position, the magnetic blanks 46a, 46b are in contact with the outer surface of the separation chamber 16.

[0078] On the rear surface of the force transfer element 38 - that is, the surface of the element facing away from the separation chamber - a pivot 54 is provided. The pivot extends integrally from the rear surface of the force transfer element 38, which allows the magnet pair 44 to "rock". The pivot 54 is offset from the center line between the two magnet blanks. Figure 4 As shown, it can be seen that the pivot 54 is slightly offset to the left. Figure 4 Directly below the visible pivot in FIG. 2 , there is another similar arrangement of magnet pairs, although the pivot is not visible because it is hidden behind the force transfer element 38. The pivot in this arrangement is offset to the right. Preferably, the offset of the pivot alternates along the magnetic assembly 24. The magnetic assembly 24 in this embodiment has four grooves, four springs, and four magnet pairs. Thus, two pivots are offset to one side and two pivots are offset to the other side.

[0079] The offset pivot is advantageous when the magnetic assembly 24 is moved from a position against the separation chamber 16 to a position spaced apart from the separation chamber 16. When a force is applied to overcome the magnetic attraction between the magnetic blanks 46a, 46b and the magnetic debris that may be present in the separation chamber to pull the magnetic assembly 24 away from the separation chamber, the magnet pair will tend to pivot so that only the magnetic blank that is away from the pivot in each case remains in contact with the separation chamber. When this happens, because half of the magnets are in contact with the separation chamber, the magnetic attraction is reduced, making it easier to completely pull the magnetic assembly away from the separation chamber.

[0080] When the magnetic assembly 24 is pulled away from the separation chamber, force is transmitted from the bracket 25 to the magnet pair through the contact of the force transmission element 38, which is integral with the bracket 25, with the ferromagnetic rod 48, which forms part of the magnet pair 44. No force is transmitted at all through the spring 40. The spring is relatively light and its purpose is purely to ensure good contact of the magnet blanks 46a, 46b with the separation chamber 16, regardless of possible surface defects on the separation chamber 16.

[0081] The magnetic filter described provides a high performance filter at a low cost which is easy to use. A range of filters can be made for a range of different sized systems using a small number of different parts available from stock.

Claims

1. A magnetic filter for a central heating and / or cooling system, the magnetic filter comprising: a chamber in the form of a cylindrical tube having a curved outer wall and an inlet and an outlet at either end of the tube; a frame fixed to the outside of the tube, the frame comprising a first rod and a second rod extending along the outside of the tube, the first rod and the second rod being parallel to the tube; a plurality of magnetic assemblies disposed along the first rod and the second rod, each magnetic assembly being elongated and curved and pivotally mounted to the second rod on a pivot disposed proximate one end of the magnetic assembly, and each magnetic assembly being movable over a major length from a position proximate the chamber to a position spaced apart from the chamber by pivoting the magnetic assembly on the second rod; as well as wherein each elongated curved magnetic component is disposed around the curved outer wall when in a position proximate to the chamber; The magnetic components are arranged in pairs to completely surround the chamber, and the magnetic components include a curved elongated bracket, an elastic clip is provided at the end of the bracket away from the second rod, and the buckle of the elastic clip connects the bracket to the first rod. 2 . The magnetic filter according to claim 1 , wherein a hole is provided on each magnetic assembly, and the second rod passes through the hole of each magnetic assembly.

3. A magnetic filter as claimed in claim 1, wherein a stop is provided to limit the extent to which each magnetic assembly can pivot away from the chamber.

4. A magnetic filter as claimed in claim 3, wherein the stop is in the form of an extension of the magnetic assembly, the extension of the magnetic assembly extending from the pivot in a direction opposite to the main length of the magnetic assembly.

5. A magnetic filter as described in claim 1, wherein at least two magnetic components are provided, wherein each magnetic component is an identical component, and wherein each magnetic component includes a section with reduced width at the end of the component, wherein the section is pivotally mounted to the second rod, and the two magnetic components are pivotally mounted to the second rod facing in opposite directions, and the main width of each component is at the same longitudinal position along the second rod.

6. The magnetic filter of claim 5, wherein the end of the magnetic assembly opposite the pivot axis includes a section of reduced width.

7. The magnetic filter of claim 1, wherein each magnetic assembly is semicircular in shape and two magnetic assemblies surround and encircle the chamber.

8. The magnetic filter of claim 1, wherein the first rod and the second rod are mounted on the frame by clamps located at both ends of the frame.

9. The magnetic filter of claim 8, wherein the clamp is a two-piece clamp.

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