GB2539953A

GB2539953A - Magnetic cleansing device

Info

Publication number: GB2539953A
Application number: GB1511664.3A
Authority: GB
Inventors: Phipson Kevin; Clews Susan; Bragger Robert
Original assignee: HEATING DISTRIB Ltd
Current assignee: HEATING DISTRIB Ltd
Priority date: 2015-07-03
Filing date: 2015-07-03
Publication date: 2017-01-04
Also published as: GB201511664D0

Abstract

A magnetic pipe cleansing device 2 is described, which comprises a housing 4 with inlet 6 and outlet 8 ports, and a magnetic element 16 for removing magnetic contaminants from fluid flowing between the ports 6,8. The primary flow pathway so defined through the device provides for reduced flow resistance, and therefore lower pressure drop across the device and thus reduced power consumption from an associated fluid pump. The magnetic element 16 may be at least one permanent magnet mounted on rod. An area 22 can also be provided where debris is collected and thus acts as a sump for the collection of debris. The device 2 may also be retro-fitted, within a central heating boiler housing.

Description

Magnetic Cleansing Device Field of the Invention

This invention relates to systems that use a recirculating fluid, such as central heating systems. More particularly, it relates to devices for cleansing such fluids, including removing or separating unwanted material from the fluids within a recirculating fluid system.

Background

Central heating systems of the type commonly found in domestic and industrial environments generally employ a working fluid, typically water, to carry heat from a central boiler through a network of pipes to one or more radiators. The fluid passes through the radiator(s), losing heat energy while doing so, and then flows back through return pipework to the boiler where it is re-heated, and the cycle repeated. These systems generally have a fluid that is, under normal working conditions, retained within the system, and so will typically flow thousands of times around the pipe network. Most such systems have a facility for topping up the fluid should levels become too low for some reason (such as leakage), and also a facility for allowing fluid to drain away from the system, either manually (when the system is drained for maintenance etc.), or automatically (for example when venting to remove excess pressure from the system.) However, such removal of fluid, is only an occasional activity, and so fluid is often retained within a system for years at a time. A consequence of this is that the fluid can become contaminated with material such as detritus from the inside of the radiators or pipes, e.g. caused by internal corrosion of the metalwork, or poor or incomplete cleaning of components during their manufacture. Contaminants such as flux, solder particles or sealing materials can be inadvertently added during installation. Contaminants inherent within the fluid itself, such as minerals etc. present when the fluid was introduced to the system, can also leech out of the fluid and accumulate into viscous fluids or solids. Poor system design that allows air ingress can also encourage corrosion, leading to further buildup of contaminants.

Contaminants present within the working fluid tend to circulate around the system, propelled by the pump that drives the fluid. Modern central heating systems comprise of many different components. One of the most vulnerable to the presence of contaminants is the heat exchanger. This comprises of a fine lattice of pipes through which the fluid flows. The pipes are subject to heat from a heat source, such as a gas flame, with the heat then heating up the fluid within the pipes. There is a motivation, promoted by legislation in the UK in 2005 requiring boilers to achieve a Sedbuck A rated 90% performance figure, for reducing the diameter of the pipes that make up the lattice, and in having more of them. This provides a greater efficiency in transferring heat from the flame to the fluid. It will be readily appreciated that, as the diameter of the pipes in the lattice making up heat exchanger reduces, their susceptibility to blocking, caused by contaminants within the fluid, increases.

Filters have been used in central heating systems for a long time. These initially comprised of wire gauze filters that collect particulates within the fluid. These proved to be effective at capturing larger particulates. However, as they catch more material they reduce the area through which the fluid may flow, and if not cleaned out sufficiently often will act as a blockage themselves. This leads to inefficient pumping of the fluid around the system and consequent wasting of energy. They also are not effective at collecting contaminants that are fluidic in nature, as they will tend to pass through.

It is known that some of the contaminants that tend to be found in central heating systems, particularly in domestic environments, have the property that they are ferromagnetic, and hence are attracted to magnets. When in suspension within the working fluid this is commonly known as magnetite. Thus another form of filter that has become popular relatively recently is the magnetic filter. These filters generally comprise of a magnet disposed within a chamber through which the fluid is diverted. A gauze may also be present within the chamber for additional filtering of the more traditional variety. They have proven to be very effective at removing more contaminants than the use of gauze filters alone. Such filters are described in UK patent publications GB2518162, GB2402894 and GB2490898. However, the design of such filters means that they cause an appreciable restriction to the flow of fluid.

Embodiments of the invention have the object of addressing one or more of the above shortcomings of the background art.

Brief Summary of the Disclosure

According to a first aspect of the present invention there is provided a cleansing device comprising a housing having a fluid inlet port and a fluid outlet port and a magnetic element disposed so as to produce a magnetic field therein, wherein the inlet and outlet together define an axis, and wherein the device is arranged to direct fluid from the inlet, past the magnetic element and through to the outlet, and further wherein a primary flow pathway through the device generally maintains a direction having a positive component along the axis throughout the flow pathway.

Thus, in use, embodiments of the invention provide a magnetic element for catching magnetite, thus preventing it from going on to block or otherwise damage the various components of the heating system.

Embodiments of the invention provide an advantage that fluid flow through the cleanser suffers from reduced impediment, as the fluid is not forced around a convoluted or unduly turbulent pathway, as happens in prior art filters. Instead, fluid flow in embodiments of the present invention always maintain a component of flow in the axial direction of the device. By maintaining a component of flow in the axial direction of the device throughout the primary flow path, the fluid is not forced to “double back” on itself, but instead always maintains a component (in the sense of a projection of the vector of flow direction) of flow, the primary flow path, in the direction between the input and output connection ports. This therefore results in a reduced pressure drop across the device, and less energy is therefore consumed by an associated (e.g. central heating) pump. It also helps to reduce noise caused by turbulent flow within the device.

In some embodiments of the invention the magnetic element comprises a rod having one or more permanent magnets mounted thereon. The magnets may conveniently comprise of ring magnets, each having a toroidal form. The magnets may be arranged to have poles oriented so that adjacent magnets have like poles positioned adjacent each other. Some embodiments may have a magnetic element arranged against a peripheral wall or surface of the device, with the magnetic field therefrom lying at least partially within the primary fluid flow path. The magnetic element may again be formed from one or more individual magnets. The poles of each magnet may advantageously be arranged to have like poles oriented the same way. The individual magnet or magnets may be of any convenient shape. Advantageously, the magnets may be of a shape conformal to the shape of the surface or wall to which they are mounted. Without limitation they may be flat, or have a curved form.

Some embodiments of the invention may be adapted to have a mounting point on the housing for the magnetic element. The mounting point may comprise an orifice arranged to receive the magnetic element, and may have means, such as a screw or bayonet mounting, for securing the magnetic element to the housing. A shroud may be located within the casing that shields the magnetic element from fluid flowing between the inlet and the outlet. The shroud may comprise a plastic, rubber, or other material suitable for immersion in a working fluid and which does not significantly impair the magnetic flux from the magnetic element. The shroud may be fixed to the housing in a permanent or semi-permanent way, such that it generally remains in place if the magnetic element is withdrawn. The shroud is advantageously sealed to prevent flow of fluid from an outside region to an inside region, such as the region where the magnetic element is arranged to reside. Thus the magnet may be removed from a system without requiring fluid within the system to be drained.

The magnetic element(s) may protrude into a flow pathway of the device, such that some or all of the fluid flowing through the pathway is subject to the magnetic field of the magnetic element. Alternatively, the magnetic element(s) may be located out of the main flow, for example in or on a side-wall of the housing, as described above.

In some embodiments of the invention the magnetic element may be located such that it reduces an internal cross-sectional area of the flow path. Preferred embodiments of the invention may have a cross sectional area at a point where it is at a minimum through the flow path, that is of at least an approximately similar value to that of the cross sectional area of the inlet and outlet ports. Other embodiments may have a minimum cross sectional area that is at least approximately 130% 80%, or 50% of that of the inlet and outlet ports.

The strength of the magnetic element may be chosen to impart a desired magnetic field into the working fluid. This may be chosen in collaboration with the cross sectional area of the primary flow path, at the point where the magnetic field is concentrated within the device, to trap a predetermined amount of the magnetic contaminants flowing therethrough, when used at expected flow rates. The predetermined amount may be approximately 30%, 20%, 10% or 5%. It will be appreciated that a greater percentage of contaminants can be trapped by either having a greater region subject to the concentrated magnetic field, or by narrowing the cross sectional area of the flow path in the vicinity of the magnetic element. The first option has the disadvantage that a larger or stronger magnetic element is required (which is expensive), and the second option has the disadvantage of restricting flow through the device (which requires more energy from the pump and may be more susceptible to blocking). Hence, lower percentages are beneficial, and, as discussed herein, such a fractional collection approach is perfectly suited to environments such as central heating systems.

Some embodiments of the invention may have a debris collection area, or sump, for removal of magnetite and other contaminants. The sump may conveniently be positioned generally beneath the magnetic element when in a mounted orientation, such that magnetite or other material that falls from the magnetic element or from a surrounding shroud will fall into the sump. The sump may comprise a region inside the housing that is not in the primary flow path, such that particulates that gather in the sump will tend not to be washed away due to the flow of working fluid through the device. Thus fluid flow into the sump may take place mainly through secondary flow paths, such as via eddy currents. The housing may conveniently be arranged to generate eddies in the flow of working fluid in the vicinity of the sump, to encourage particulates to be removed from the primary flow path and to settle in the sump. Preferably, the means for generating eddies in the flow is arranged to generate only minor eddies, such that the main flow of working fluid is not subject to turbulent or chaotic flow. This therefore aids in the reduction of any pressure drop through the device, while still providing a cleansing action. The means for generating eddies may comprise indentations or embossed elements on an inner surface of the housing, or may otherwise comprise formations on the inner surface of the housing that interrupt laminar flow of fluids passing therethrough.

The sump may comprise a separate vessel in fluid communication with the primary flow path, or may comprise an expanded part of a pathway through the device which is outside of the primary flow path of working fluid. The sump may therefore comprise a part of the device where the velocity of fluid flow is reduced as compared to the velocity of fluid flow in the primary flow pathway.

Means may be provided in the sump for aiding the retention of particulates that have gathered therein. Such means may comprise a gauze, or perforated plate etc. The sump advantageously has means for removing any particulates gathered therein.

This may conveniently comprise a removable plug or cap.

It will be appreciated that, as described herein, some embodiments of the invention may use a fractional collection approach to removal of contaminants. In other words, these embodiments may be arranged such that, during a given pass of a unit of fluid, they do not attempt to remove all of the contaminants present. Instead, they rely on the fact that the fluid will be circulated many times, generally many hundreds of times, around the circuit. By attempting to remove only a fraction of the contaminants present in such a unit of fluid at each pass, the device is able to provide a reduced resistance to the fluid, and hence not take so much energy from the pump system. Also, by not forcing the fluid flow around a convoluted flow path typical in prior art systems, noise caused by the fluid running against the walls of the device is reduced. This is because turbulent flow is often generated when the fluid is forced to undergo sudden changes of direction, and this turbulent flow is a significant source of noise.

Some embodiments of the invention may have a mounting point for the magnetic element that is arranged on an upwardly facing, or upper surface of the housing, when in a mounted orientation. The magnetic element may therefore be removable from the housing in an upward direction.

Some embodiments may have a magnetic element that is mountable to the sump plug. The magnetic element may be removably attachable to the sump plug, e.g. by means of a thread or bayonet fitting. Advantageously, the magnetic element may be removable from the sump plug whilst the sump plug remains attached to the cleansing device housing. A shroud, e.g. similar in function to that described above, may advantageously be attached to the sump plug that provides a fluid seal between the magnetic element and the working fluid. Such embodiments provide the advantage that the magnetic element may be removed whilst leaving the sump plug in place, and so without requiring the device to be drained. Also, the shroud may be removable with the sump plug, allowing ease of maintenance or replacement of the shroud should it be required.

Some embodiments of the invention may have gauze or similar filter in the primary flow pathway. Preferred embodiments however will not have a gauze in the primary flow pathway, so that improved flow through the primary flow pathway of the device is achieved.

Some embodiments of the invention may be arranged to impart a helical flow to working fluids passing therethrough. Such a flow pattern aids the removal of particulates, by encouraging the fluid to remain in the vicinity of the magnetic eiement for a slightly longer period, when such element is located in the vicinity of the helical flow. Advantageously the magnetic element is arranged to sit at least partially in a generally central part of the helical flow. Alternatively, the magnetic element(s) may be located at an outer part of the helical flow. The helical flow may be encourages by shaping the flow path. For example, shaping the internal surface of the flow pathway may be done, by the addition of vanes or other means for directing fluids. The vanes or other means may be arranged to push fluids to one side of the flow pipe as it flows, which will have the effect of inducing rotation within the pipe as it flows. Other means for encouraging helical flow may also be used, as appropriate.

Some embodiments of the invention may have a primary flow pathway that is generally V-shaped, or of a “swan neck” form when viewed with the axis horizontal, with input and output ports similarly arranged to accept and deliver fluids in the direction of the axis. Advantageously, the input and output ports are located on the axis, so as to provide for convenient in-line installation.

The housing itself may also have a similar V shaped or swan neck form, or may alternatively be arranged to enclose an internal structure that provides the primary flow pathway with such a V shaped form.

It will be understood that reference here to the V-shaped form should not be taken as strictly adhering to a classical V shape, but instead it should be interpreted as sharing general characteristics with a V shape, e.g. having angles and curves that, in certain orientations (not necessarily that of an orientation when mounted in use) that are also present or suggested by the form of a letter V.

Advantageously, the internal surfaces of the housing are generally oriented, when mounted for use, to allow bubbles to pass through the device and not to become trapped within the device. With this aim, internal surfaces may be angled or curved to allow air bubbles to flow through to either the inlet or the outlet port and hence out of the device. Alternatively or as well, some embodiments may have means, such as a port or valve, for discharging air from the device.

The invention may alternatively be seen as a cleansing device comprising a housing having a fluid inlet port and a fluid outlet port and a magnetic element disposed so as to produce a magnetic field therein, wherein the device is arranged to direct fluid from the inlet, past the magnetic element and through to the outlet through a primary flow pathway, wherein the primary flow pathway through the device has a minimum cross sectional area that is of at least 50% of the cross sectional area of flow path of pipes to which the inlet and outlet ports are designed to be attached.

The invention may alternatively be seen as a cleansing device comprising a housing having a fluid inlet port and a fluid outlet port and a magnetic element disposed so as to produce a magnetic field therein, wherein the device is arranged to direct fluid from the inlet, past the magnetic element and through to the outlet through a primary flow pathway, wherein a debris collection region is provided that is attached or formed alongside the primary flow path, and where fluid flows substantially thereto by means of eddy currents or other secondary flows generated from the flow through the primary pathway.

Embodiments of the invention are particularly suited to installation within a boiler. Preferred embodiments of the invention have an inlet port and an outlet port that are in-line, and oriented along the axis. This allows ready installation into an existing pipe, such as an inlet pipe to a pump, by cutting a portion of the pipe away. Some embodiments may be particularly compact, without having significantly sized components located off-axis. This again makes embodiments of the invention particularly suited to installation into relatively small volumes.

Some embodiments of the invention may be of generally elongate form, albeit with variations from this form to accommodate changes in the primary flow path direction. Some embodiments may have the inlet and outlet ports mounted at generally opposing ends of the housing, such that the magnetic field within the primary flow path sits generally between the inlet and outlet ports. This, coupled with the primary flow path lying generally along the axis defined by the locations of the ports, helps to reduce flow restrictions that are commonplace in prior art devices.

The invention extends to a boiler comprising a cleansing device as described in one or more of the claims.

Brief Description of the Drawings

Embodiments of the invention are further described in detail hereinafter, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 diagrammatically illustrates a first embodiment of the present invention, having a generally “V” shaped, or swan-neck primary flow path;

Figure 2 diagrammatically illustrates a second embodiment of the present invention;

Figure 3 diagrammatically illustrates a third embodiment, broadly similar to the first, but having a magnetic element combined with a sump cap; and

Figure 4 diagrammatically illustrates a fourth embodiment of the invention having a magnetic element mounted on a sidewall of the device.

Detailed Description

Figure 1 shows an embodiment of a cleansing device according to the present invention. Device 2 comprises a housing 4 having a fluid inlet port 6 and a fluid outlet port 8, which together define an axis 10, and thus allow in-line fitting of the device to a pipe without a requirement to axially move the existing pipe. The housing 4 provides a curved internal pipe 12 for directing fluid from the inlet to the outlet. The housing has a threaded orifice 14 for receiving magnetic element 16. Attached to one end of magnetic element 16 is a threaded portion along with a hex nut 18 for engaging with threaded orifice 14. A shroud 20 surrounds the portion of the magnetic element 16 that sits within housing 4, and is fixably attached to the housing.

The housing 4 has a region generally below (when in a mounted orientation) the magnetic element that comprises a debris collection region 22 that sits generally outside a main flow path of working fluid. The debris collection region is completely open to the pipe 12, and thus may alternatively be regarded as an expanded part of the pipe 12 that is outside of a primary flow path.. At the bottom of the debris collection region 22 is an orifice and a threaded plug 24. When suitably inserted and tightened, the plug 24 provides a fluid-proof seal preventing egress of fluid from the region 22.

The debris collection region acts as a sump which, due to its orientation when mounted, tends to collect heavy particulates that drift into the region 22. As the region 22 is not in a primary flow path, meaning that the flow rate of fluid within the region 22 will be relatively low, as compared to that within pipe 12, the particulates will tend not to be washed away back into the system once more.

Alternative embodiments may have a gauze or other mesh-like or perforated material, that acts to reduce further any fluid flow that is present in the sump, while providing for collection of particulates.

The pipe 12 has a curvature that takes the primary flow path through an approximate right angle, which conveniently provides a location at which the magnetic element may be introduced. Thus, the magnetic element is positioned to occupy a broadly central region of the pipe and hence the flow path, at least for a portion of the pipe’s extent (and disregarding the debris collection region).

In use, the inlet and outlet ports are connected by standard pipe fittings to a generally vertically oriented pipe. Preferably, a pipe is chosen that sits between (for a central heating system), a last radiator and a main central heating pump, although it will be appreciated that this is not a necessary condition for operation of the device. Fluid will therefore flow into the device from the lower port and will follow the course defined by pipe 12. As it meets the magnetic element with its surrounding shroud, then particles of magnetite will tend to be drawn to the magnetic element. Those that are closest to it will tend to be caught by the magnetic field, and hence stick to the side of shroud 20. Thus these particles are then effectively removed from the working fluid, Other, heavy but non-magnetic particles will not be affected by the presence of the magnetic element. However, the presence of the sump 22 will cause some of the fluid to eddy in the vicinity thereof, and heavy particulates in that eddying fluid will tend to be removed from the flow and settle at the bottom of the sump. The low current flows at that point will generally prevent such settled particles from being re-introduced to the primary current path.

Periodically, the device 2 will require emptying, to permanently remove the particulates from the working fluid. To do this, the device is preferably isolated, by means of isolation valves located proximate to the input and output ports. The sump plug 24 is then loosened and removed, whilst using means to catch the fluid within the device (and trapped between the isolation valves) that will also fall out.

Preferably, when emptying the device, the magnetic element should also be removed from the housing. The magnetite that has gathered onto the shroud 16 will then lose the magnetic force holding it in place, and will tend to fall under gravity, through to the sump region and hence out of the device.

The cross sectional area of the flow path indicated by dotted lines 24 (i.e. the point having the lowest cross sectional area within the flow path of the device) is similar to the cross sectional area of connected external pipework. Thus, the device provides minimal obstruction to the flow of fluids therethrough.

The pipe 12 always maintains a positive component in the direction of the axis 10. In other words, it does not have a primary flow path that doubles back on itself, in relation to the axis 10. In this way, excessive flow turbulence is avoided, which leads to reduced noise and reduced pressure drop across the device.

Figure 2 shows a second embodiment of the invention. Here, device 30 comprises a housing 32 having a fluid inlet port 34 at a first side 35 of a lower region thereof and a fluid outlet port 36 again at the first side 35 of an upper region thereof, which, as with the embodiment discussed above, together define an axis 10. The housing 4 is generally of rectangular aspect, although it will be appreciated that such a form is used merely for convenience, and also that detail elements of the design cause it to divert from the rectangular in many different aspects. Other embodiments may therefore appear different in general shape, while maintaining similar functional characteristics.

The housing 32 has a curved wall that diverts in-flowing fluid to a second side 40 of the housing. Fluid entering the second side then exits by flowing once more to the first side 35, and then out of the outlet port 36 of the device, guided by curved wall 42. The primary flow path of the embodiment is therefore from the first side 35, to the second side 40, and then back to the first side and the exit. The second side has positioned therein a magnetic element 44 that is broadly centrally located with respect to at least a part of the primary flow path. As fluid is directed from the first side to the second side, a shaping, comprising an asymmetry of the curvature of the walls, directs the fluid to have a helical flow when in the second side. Thus, the fluid is generally directed to flow around the magnetic element, as generally indicated by line 46, although it will be readily appreciated by those skilled in the art that fluid flow detail tends to be at least slightly turbulent and difficult to predict, and so this is only an indication of the primary flow path.

Upper surface 48 (when in a mounted orientation) has a slope thereon to encourage any air bubbles that enter the device to be swept up through the outlet port, rather than accumulate within the device. This obviates the requirement for an air release valve on the device. However, some alternative embodiments may have a port located on an upper surface thereof for expelling air that may gather in the device during use, and may consequently not have the slope on the upper surface.

The upper surface 48 has a mount for holding magnetic element 44 in place. The element 44 again comprises a set of toroidal magnets secured onto a rod, with an end cap 52 that screws into mount 50, to secure it in place. A plastic shroud 54 is affixed to the inside of the device for receiving the magnetic element, and for isolating it from working fluid flowing therethrough. A debris collection region 56 that acts as a sump is located on the second side 40, generally underneath (when in a mounted configuration) the magnetic element 44. A short wall 58 separates the debris collection region from the primary flow path. The debris collection region therefore sits out of the primary flow path of the device, and fluid tends to enter it in the form of eddy currents generated e.g. at a point, such as at the top of wall 58, between the first and second sides of the device. Within the debris collection region 56 is located a detachable sump plug 60, in similar fashion to that described in relation to the embodiment of Figure 1. A gauze or perforated plate 62 is present at an upper part of the debris collection region.

In use, the inlet and outlet ports function in similar fashion to the embodiment of Figure 1. Fluid entering the inlet port is directed to the second side in asymmetric fashion causing most of the fluid to rotate helically around the magnetic element 44 before being forced once more to the first side and then out of the device. Some of the fluid will be diverted from this primary flow path due to friction or eddy currents caused e.g. by the lip of wall 58.

Cleansing action takes place in similar fashion to that described with respect to Figure 1, with magnetic material being drawn to the magnetic element, and nonmagnetic heavy particulates tending to settle within the sump, or debris collection region. As the flow rate within the debris collection region is much less than in that of the primary flow path, the particulates that gather therein tend not to be washed away by the normal flow of the working fluid through the device. The sump is emptied periodically as previously described.

Figure 3 shows a third embodiment of the invention. This comprises a cleansing device 70 broadly similar to that of Figure 1, in terms of the general form of the primary flow path. This embodiment is shown connected to isolation valves 72, 74 at the inlet and outlet ports, as would typically, but not necessarily, be the case.

Operation of this embodiment is similar to that of Figure 1, in that an inlet port 76 allows working fluid to flow through a primary flow path generally indicated by arrow 78, that takes the fluid to outlet port 80. A magnetic rod 82 is connected to a cap 84, which is itself attached, by means of a screw thread, to sump plug 86. Plug 86 screws into a drain port of the device 70, which sits below a contaminant collection region 87. Attached to the sump plug 86 is a shroud that provides fluid isolation between fluid in the primary flow path and the magnetic element 82. As fluid passes through the device 70 some of the magnetic contaminants will be attracted to the magnetic rod 82 as described in relation to previous embodiments. They will thus tend to accumulate against the shroud 88.

Periodically, magnetic element 82 may be removed by unscrewing cap 84 from plug 86, which will allow accumulated contaminants to fall down into the collection region 87 and hence remove them from the primary flow path 78. Any contaminants in this region will tend not to get washed away, as fluid velocities are reduced in this area. Shroud 82 prevents working fluid from leaking out of the device, and obviates any need to drain the device during this process. At greater intervals the sump plug may be removed (following any required isolation of the device e.g. by using valves 72 and 74) by unscrewing it from the housing, bringing the magnetic element along with it. This then allows complete removal from the system of any contaminants that have gathered, and also allows maintenance to be carried out on the shroud 88 if required.

Figure 4 shows a fourth embodiment of the invention. Device 90 comprises a generally elongate housing having an inlet port 92 and an outlet port 94, shown connecting to respective isolation valves 96, 98. The device has a main body portion 100 that defines a primary flow path indicated generally by arrow 102. Located on a side wall of body 100 is a magnetic element block 104 that contains a plurality of rare earth magnets that impart a magnetic field into body 100. The magnetic block 104 is held in place with a clip (not shown) and is conveniently removable. A shroud 106 is connected to an internal surface of body 100 that isolates the magnetic element from fluid flowing within body 100, and allows removal of the block 104 without requiring drainage of the device.

Positioned at the bottom (when in a mounted configuration) of the device 90 is a collection region 108, that lies generally out of the primary flow path. A sump plug 110 is provided that screws into the body 100 and allows material within the collection region to be removed.

In use, fluid flowing up through the device (when in its mounted orientation) passes through the magnetic field provided by magnetic elements 104. Magnetic contaminants that are close to the magnetic element will tend to be drawn to the element and thus accumulate against the shroud 106. As with other embodiments, the magnetic element may be periodically removed, thus allowing magnetite to fall from the shroud 106 into the collection region 108. As this is not in the primary flow path the velocity of fluid flow in this region is much reduced, and hence material gathered therein does not tend to be forced out of the device, and back into the e.g. heating system, by fluid flow during normal operation of the system. The sump plug 110 may be removed as required to permanently remove any contaminants that have gathered in the collection region.

The inlet and outlet ports for these embodiments may be of any convenient type. They may conveniently be made to be compatible with standard 22mm pipes, or to other diameters as desired. They may have swaged ends for attaching to other pipework using conventional means. Alternatively, they may have a threaded fittings, such as to connect to standard BSP fittings. Alternatively, they may have fittings designed for push-fit assembly, such as those from Sharkbite™ or Tectite™ . These have the benefit of providing an electrical flow path for grounding purposes.

However, other, non-conductive systems may also be used where such electrical conductivity is not required.

Some embodiments may be elongated in the axis of the helical flow, which will tend to promote a greater number of rotations around the magnetic element and hence have a stronger cleansing effect of the magnetic particles. This however requires a larger cleanser and may cause a slight increase in pressure drop in the device. Thus different embodiments may be chosen for different purposes.

It has been emphasized that the cleansing performed in embodiments of the invention is of a fractional collection variety, in that it does not attempt to catch all of the particulates on the first pass. For application to central heating systems and the like, this still provides adequate cleansing, but with the consequential benefits as discussed above. Even with a cleansing fraction of only 10% (meaning that the device will remove 10% of the particulates present at each pass through the cleanser), it only requires around 21 cycles through the system to remove 90% of the particulates present. When this is coupled with the knowledge that the particles are generally slow to form, then it can be appreciated that it is beneficial to adopt the fractional collection technique described herein and reap benefits in terms of energy saved in driving the pump.

The embodiments above have been described with a fluid inlet at the bottom of the device and an outlet at the top, when in an installed orientation. However, some embodiments may be arranged to have an inlet at the top and outlet at the bottom, although this is generally not a preferred orientation. The normally skilled person will appreciate that the invention is also applicable for use in other orientations, such as a generally horizontal orientation, and will appreciate the changes in sump position (to keep the sump generally at a lower part of the device when mounted) that may be done to optimize the collection of contaminants.

The functions described herein as provided by individual components could, where appropriate, be provided by a combination of components instead. Similarly, functions described as provided by a combination of components could, where appropriate, be provided by a single component.

Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. A cleansing device comprising a housing having a fluid inlet port and a fluid outlet port and a magnetic element disposed so as to produce a magnetic field therein, wherein the inlet and outlet together define an axis, and wherein the device is arranged to direct fluid from the inlet, past the magnetic element and through to the outlet, and further wherein a primary flow pathway through the device generally maintains a direction having a positive component along the axis throughout the flow pathway.

2. A cleansing device as claimed in claim 1 wherein the magnetic element comprises a rod having one or more permanent magnets mounted thereon.

3. A cleansing device as claimed in claim 1 or claim 2 wherein the magnetic element has a mounting point on the casing, and wherein the magnetic element is arranged to protrude from the housing into the flow pathway.

4. A cleansing device as claimed in claim 1 or claim 2 wherein the magnetic element comprises a detachable panel attachable to a peripheral surface of the device.

5. A cleansing device as claimed in any of the above claims wherein the device further comprises a shroud adapted to isolate fluid flow from the magnetic element, and which prevents fluid egress from the device if the magnetic element is removed.

6. A cleansing device as claimed in any of the above claims wherein a debris collection region is provided that acts as a sump, and is attached or formed alongside the primary flow path, and where fluid flows mainly thereto by means of secondary currents.

7. A cleansing device as claimed in claim 6 wherein a gauze or perforated material is located in the debris collection region.

8. A cleansing device as claimed in claim 6 or claim 7 wherein the debris collection region has fluid flows, when in use, that are of reduced velocity as compared to the velocity of fluid flows of the primary flow path.

9. A cleansing device as claimed in any of claims 6 to 8 wherein, when in a mounted orientation, the debris collection region sits at a point in the housing below the magnetic element.

10. A cleansing device as claimed in any of claims 6 to 9 wherein the debris collection region has an access port therein.

11. A cleansing device as claimed in claim 10 wherein the access port has a detachable plug, and wherein the plug further has means for detachably mounting the magnetic element.

12. A cleansing device as claimed in claim 11 when dependent upon claim 5 wherein the shroud is attached to the sump plug such that, in use, the magnetic element may be removed whilst retaining isolation of fluid within the device.

13. A cleansing device as claimed in any of the claims 1 to 10 wherein the mounting point for the magnetic element is arranged on an upwardly facing surface of the housing, when in a mounted orientation.

14. A cleansing device as claimed in any of the above claims wherein the device is adapted to impart a helical flow to fluids passing therethrough.

15. A cleansing device as claimed in claim 14, when dependent upon claim 3, wherein the magnetic element is arranged to sit at least partially in a generally central part of the helical flow.

16. A cleansing device as claimed in any of the above claims wherein the inlet and outlet ports are oriented along the axis to allow in-line installation.

17. A cleansing device as claimed in claim 16 wherein the inlet and outlet ports are positioned at generally opposed ends of the housing.

18. A cleansing device as claimed in any of the above claims wherein the primary flow pathway is generally V-shaped, when viewed with the axis horizontal.

19. A cleansing device as claimed in claim 18 wherein the housing comprises a moulding having a generally V-shaped, swan-neck form.

20. A cleansing device as claimed in any of the above claims wherein the housing has, when in a mounted orientation, internal surfaces that are angled to allow air bubbles to flow through to either the inlet or the outlet port

21. A cleansing device as claimed in any of the above claims wherein the primary flow path through the device has a minimum cross sectional area that is of at least 50% of the cross sectional area of flow path of pipes to which the inlet and outlet ports are designed to be attached.

22. A cleansing device as claimed in claim 21 wherein the minimum cross sectional area of the primary flow path is at least 80%.

23 A cleansing device as claimed in claim 21 wherein the minimum cross sectional area of the primary flow path is at least 100%.

24 A cleansing device as claimed in claim 21 wherein the minimum cross sectional area of the primary flow path is at least 130%.

25. A cleansing device as claimed in any of the above claims wherein the cross sectional area of the primary flow path during passage through a magnetic field from the magnetic element combine with the magnetic field to stop approximately 30% of magnetic contaminants flowing therethrough in a single pass.

26. A cleansing device as claimed in claim 25 wherein approximately 20% of magnetic contaminants are stopped in a single pass.

27. A cleansing device as claimed in claim 25 wherein approximately 10% of magnetic contaminants are stopped in a single pass.

28. A cleansing device as claimed in claim 25 wherein approximately 5% of magnetic contaminants are stopped in a single pass.

29. A cleansing device as claimed in any of the above claims wherein the primary flow path does not contain a gauze or mesh filter.

30. A boiler comprising a cleansing device as claimed in any of the above claims.

31. A cleansing device as hereinbefore described, with reference to any of figures 1 to 4