GB2534162A

GB2534162A - Central heating apparatus

Info

Publication number: GB2534162A
Application number: GB1500579.6A
Authority: GB
Inventors: Salmon David
Original assignee: GREENPOLLY Ltd
Current assignee: GREENPOLLY Ltd
Priority date: 2015-01-14
Filing date: 2015-01-14
Publication date: 2016-07-20
Anticipated expiration: 2035-01-14
Also published as: GB2534162B; GB201500579D0

Abstract

A device 202 for detecting corrosion in a central heating system having a conduit 204 formed from a non-magnetic material comprises a magnet 208 and a holder 206. The magnet 208 is held against or adjacent the outer surface 210 of the conduit by the holder 206 and attracts ferromagnetic particles 212 dispersed inside the conduit 204. The holder may be held on to the conduit for a test period and then removed by sliding or rotating to release the magnet so that movement of the magnet under gravity provides an indication of no or undetectable corrosion in the system. The test period may be up to half an hour or up to week. The magnet may comprise an alloy of iron, nickel or cobalt and may have a magnetic moment of over 10000 Gauss and a weight of up to 20 grams. The holder may comprise a housing to enclose the magnet and a retaining member to hold the magnet against the conduit.

Description

CENTRAL HEATING APPARATUS

The present invention relates to an apparatus for detecting the presence of corrosion, particularly in central heating systems.

Conventional wet central heating systems comprise a series of radiators to which warm water is supplied through pipes from a gas, oil or electrically powered boiler or heater. It is a well known problem, however, that over time, the inner surfaces of the steel system components corrode, reducing the overall efficiency of the heating system and causing premature system failure.

Corrosion inhibitors may be added to the system water to prevent corrosion. In addition, magnetic filters or separators may be fitted to the central heating system to remove the products of corrosion from the circulating water. The system water passes through the magnetic filter, which attracts any ferromagnetic particles dispersed therein. Examples of magnetic separators are provided in GB 2510011 and US 2014/0069855.

Corrosion inhibitors and magnetic filters or separators are usually added when a new boiler is fitted or employed only once it has been established that an existing central heating system has suffered failure from corrosion.

To test a central heating system for corrosion, a sample of water is 20 typically removed from the system and tested separately.

GB 2471688 discloses a water tester for testing the presence of corrosion in a central heating system. The water tester comprises a magnet and a plastic cover member, the cover member having a handle portion and a testing portion, the testing portion having an aperture therein for receiving the magnet and a plug member for sealing the aperture. The portion of the tester enclosing the magnet is to be held in a stream of the heating system water. If, over time, the magnet discolours, this provides a positive indication that the system has corroded.

Testing devices such as this are impractical as a sample of water must first be removed from the central heating system. As a consequence, they are generally employed by professionals and not by the average home owner, for example. In addition, such devices rely upon the user's perception of a change in colour. As a consequence, there is a high risk that low levels of corrosion are not detected at an early stage.

Accordingly, there remains a need for an improved device for testing the presence of corrosion in central heating systems. It would be particularly advantageous if the device could provide an indication of corrosion at an early stage in the onset of corrosion.

The present invention provides, in a first aspect, a device for detecting corrosion in a central heating system having a conduit formed from a non-magnetic material, the device comprising: a magnet for attracting ferromagnetic particles within the conduit; a holder for releasably holding the magnet and for mounting the device to the conduit; and wherein in use the magnet is releasably held against or adjacent the outer surface of the conduit by the holder.

In a further aspect, the present invention provides a method for detecting corrosion in a central heating system having a conduit formed from a nonmagnetic material, the method comprising: releasably holding a magnet against or adjacent the outer surface of the conduit for a test period; and releasing the magnet at the end of the test period, such that it is able to fall or be displaced under gravity; wherein movement of the magnet under gravity provides a positive indication that there is no or undetectable corrosion in the system.

The device of the present invention can be used to detect corrosion in a central heating system. Corrosion is typically caused by oxidation of the iron content in steel radiators although it can also be caused by galvanic action, this being an electrochemical process in which one metal corrodes preferentially to another when both metals are in electrical contact. Either way, the products of corrosion disperse in the circulating water and gradually collect on the inner surfaces of the system, creating what is commonly seen as black sludge.

The products of corrosion within the heating system include ferromagnetic particles. These are materials which are attracted to magnets. In central heating systems, iron oxide (Fe203) is the most common ferromagnetic particle although other ferromagnetic particles may also be present, including iron, nickel, cobalt and oxides or metal alloys of such metals.

The device of the present invention is to be used to detect corrosion in a central heating system having a conduit formed from a non-magnetic material.

As will be discussed in more detail below, the device comprises a magnet which, in use, is held against or sufficiently close to the outer surface of the conduit and attracts ferromagnetic particles present within the conduit. A positive indication that the system has corroded is provided if the magnet remains held against the outer surface of the conduit when the magnet is released from the holder of the device. A negative indication is provided when the magnet, once released from the holder, falls under the action of gravity. Accordingly, the conduit must be formed from a non-magnetic material; otherwise the magnet would remain held against the outer surface of the conduit irrespective of whether any ferromagnetic particles were present within the conduit. Suitable non-magnetic materials for the conduit include copper and plastic. In a preferred embodiment, the conduit is a copper pipe as these are found in most central heating systems.

As discussed above, in use, the device of the present invention holds a magnet against or adjacent the outer surface of a conduit of a central heating system. Accordingly, the device is advantageous in that it is simple to use and install as it does not need to gain access to the interior of the heating system in order to function and no modification to the heating system is necessary.

The device of the present invention comprises a magnet for attracting ferromagnetic particles within a non-magnetic conduit of a central heating system. The magnet is releasably held against or adjacent the conduit by a holder. In use, the holder of the device releasably holds the magnet against or Zo close to the outer surface of the conduit. If, when the magnet is released from the holder, the magnet remains in position against the outer surface of the conduit, this provides a positive indication that the system has corroded. In such circumstances, the magnet is attracted to the ferromagnetic particles present within the conduit that have collected in the region of the magnet and this alone is sufficient to hold the magnet against the outer surface of the conduit. If, when the magnet is released from the device, the magnet falls or is displaced by gravity, this provides a positive indication that there is no corrosion or that corrosion is minimal and undetectable.

In one embodiment, the device of the present invention is used to releasably hold the magnet against the outer surface of the conduit for a prolonged period of time or indefinitely. In one manner of use, the device is fitted to a new or recently cleaned heating system for a prolonged period of time, for example for several days, weeks or months, and is used periodically to test for corrosion. In this way, the device is capable of detecting very low concentrations of ferromagnetic particles and indicating to the user the presence of corrosion at an early stage. This means that the corrosion can be treated much more easily and more effectively, reducing the overall cost implications for the system owner.

At the early stages in the onset of corrosion, ferromagnetic particles are highly dispersed in the circulating water of the system. In such circumstances, use of the device of the present invention as discussed above would indicate no or minimal corrosion. However, when held against the outer surface of the conduit for a prolonged period of time, the device gradually attracts the dispersed ferromagnetic particles to collect on the inner surface of the conduit adjacent the magnet. Once a sufficient amount of ferromagnetic particles has collected on the inner surface of the conduit to hold the magnet in place when released, use of the device as discussed above would indicate the presence of corrosion. Despite the total concentration of ferromagnetic particles being relatively low, the device of the present invention causes a relatively high concentration of ferromagnetic particles to collect on the inner surface of the conduit in the region of the magnet. As a consequence, the magnet remains held against the outer surface of the conduit when released from the holder.

In a preferred embodiment, the device is used to releasably hold the magnet against the outer surface of the conduit for a relatively short period of time, for example for a number of minutes or hours. In a particularly preferred embodiment, the device is employed by a plumber or the like and is used to releasably hold the magnet against the outer surface of the conduit for the duration of the time the system is being serviced or repaired. Whilst the magnet is releasably held against the outer surface of the conduit, the magnet can be released from the device once or several times to test the system for corrosion, although the magnet is preferably released from the device only once, at the end of the period set by the user.

In an alternative embodiment, the device is applied to the conduit and the magnet released immediately. If the magnet remains in position on the conduit after the holder has been moved, this indicates the presence of a layer or coating of ferromagnetic particles on the inner surface of the conduit, in turn suggesting a more advanced stage of corrosion within the system.

As noted above, the device of the present invention comprises a magnet. The magnet can be of any suitable shape or size. In addition, the 30 magnet can be formed from or comprise any suitable magnetic material. For example, the magnet can be formed from or comprise magnetic materials such as iron, nickel, cobalt or alloys thereof.

The magnet can be formed from or comprise materials of any suitable weight. However, fewer ferromagnetic particles are required within the conduit to retain a lightweight magnetic material in position on the outer surface of the conduit. Accordingly, to decrease the sensitivity of the device, the weight of the magnet is increased. Conversely, to increase the sensitivity of the device to low levels of ferromagnetic particles within the system, the weight of the magnet is reduced. The magnet is preferably formed from or comprises lightweight materials having a weight of up to 20 grams, more preferably up to grams, more preferably still up to 5 grams, yet still more preferably up to 1 gram.

The magnet can be of any suitable strength. The strength of a magnet may be indicated in terms of its magnetic moment. Preferably, the magnetic moment of the magnet is up to 10 Gauss, more preferably up to 100 Gauss, more preferably still up to 1000 Gauss. To increase the sensitivity of the device, the magnetic moment of the magnet is preferably greater than 1000 Gauss, more preferably greater than 10,000 Gauss, more preferably still greater than 100,000 Gauss.

The sensitivity of the device, that is the extent to which it is capable of attracting a particular concentration of ferromagnetic particles within the conduit, can be varied by adjusting the weight and/or strength of the magnet as discussed above. In one embodiment, the magnet is both lightweight and strong.

The sensitivity of the device will also vary depending on the length of time the magnet is held against the outer surface of the conduit as this affects the concentration of ferromagnetic particles present on the inner surface of the conduit adjacent the magnet. As discussed above, the magnet is capable of attracting ferromagnetic particles present within the conduit such that they collect on the inner surface of the conduit adjacent the magnet. The sensitivity of the magnet will therefore increase as more ferromagnetic particles collect on the inner surface of the conduit adjacent the magnet, for a given system. As will be appreciated, the greater the time the magnet is left in contact with or adjacent the conduit, the greater will be the number of ferromagnetic particles attracted to the inner surface of the conduit in the region of the magnet. Accordingly, an indication of the extent or amount of corrosion will also depend upon the length of time the magnet is held on or adjacent the conduit.

A central heating system will generally only be cleaned or replaced if the io system tests positive for a particular threshold concentration of ferromagnetic particles since it is impractical and costly to clean or replace central heating systems having lower concentrations of ferromagnetic particles. It is to be appreciated that device may be calibrated to provide a quantitative indication of the extent of corrosion by adjusting the strength of the magnet, the weight of is the magnet and the time the magnet is held in contact with or adjacent the conduit. In one embodiment, the device of the present invention is provided with a plurality of magnets, having different weights and/or magnetic strengths.

As noted above, the device of the present invention further comprises a holder, for releasably holding the magnet and for mounting the device to the conduit. In use, the holder releasably holds the magnet against or sufficiently close to the outer surface of the conduit, so as to attract ferromagnetic particles within the conduit. In this respect, the holder may releasably hold the magnet in contact with the outer surface of the conduit or close to the outer surface of the magnet.

Preferably, the holder holds the magnet in contact with the outer surface of the conduit.

In use, the holder can be moveable with respect to the conduit, in which case movement of the holder causes the magnet to be released and to be free

S

to move under gravity. In this respect, the holder may slide along and/or rotate around the conduit to release the magnet from the device. In such circumstances, the shape of the holder is such that it is capable of holding the magnet against the outer surface of the conduit in a first position but unable to s do so in a second position. Moving the holder between the first and second positions causes the magnet to be released.

Alternatively, the holder may be partially or fully removed from the conduit to release the magnet.

As a further alternative, the holder can be fixed with respect to the conduit. In one embodiment, the holder is fixed to the outer surface of the conduit. The holder is provided with a body and a retaining member for retaining the magnet against or close to the outer surface of the conduit. The retaining member is moveable with respect to the body, such that the magnet can fall or be displaced by gravity, when the retaining member is moved with respect to the body. In this embodiment, the body is shaped so as to allow the magnet to fall or move under gravity when the retaining member is moved with respect to the body.

As discussed above, a positive indication that there is no or minimal corrosion is provided if, when the magnet is released from the holder, the magnet falls or is displaced by gravity. To avoid losing the magnet when it moves or is displaced by gravity, the holder may be provided with a housing to retain the magnet. The housing may be of any suitable shape, provided it allows the magnet to move to some extent by gravity, as this provides an indication to the user that there is no or minimal corrosion. The housing may form an enclosure around the magnet, in which case the enclosure is preferably transparent. In this way, the user can see whether the magnet moves under gravity within the housing when released from the device.

In a still further aspect, the present invention provides a kit of parts for detecting corrosion in a central heating system having a conduit formed from a non-magnetic material, the kit of parts comprising: a device as hereinbefore described; and one or more additional magnets.

Embodiments of the present invention will now be described by way of example only, having reference to the accompanying drawings, in which; Figure 1 is a perspective view of one embodiment of the device of the present invention.

Figure 2a is a cross sectional view of the device of Figure 1, mounted to a conduit of a central heating system, at the early stages in the onset of corrosion.

Figure 2b is the cross sectional view of Figure 2a, wherein the device has been mounted to the conduit for a prolonged period of time.

Figure 2c is the cross sectional view of Figure 2b, wherein the holder has been moved with respect to the conduit, releasing the magnet.

With reference to Figure 1, there is shown a device of one embodiment of the present invention, generally indicated as 2.

The device, 2 comprises a holder 4 for releasably holding a magnet 6. The holder 4 comprises resilient arms 10 for releasably mounting the device 2 to the outer surface of a conduit of a central heating system. As shown, the arms 10 clip the holder 4 onto the conduit. The device 2 may be used with a vertical or horizontal conduit of a central heating system.

The holder 4 comprises a recess 8 in its inner surface extending from one edge of the holder, the recess 8 forming a ledge 12 upon which the magnet 6 can sit. The recess 8 is also provided with an opening 14 at the edge, to allow the magnet 6 to be released from the holder 4 when the holder 4 is moved relative to the conduit. With reference to Figure 2a, there is shown a device of one embodiment of the present invention, generally indicated as 202. The device 202 is shown mounted to a vertical conduit 204 of a central heating system. The device 202 comprises a holder 206 for holding a magnet 208 against the outer surface 210 of the conduit 204. At the early stages in the onset of corrosion, the ferromagnetic particles 212 are highly dispersed inside the conduit 204.

The device 202 is left mounted to the conduit 204 for a period of time. The effect of this is illustrated in Figure 2b. As shown, the ferromagnetic particles 212 are no longer highly dispersed but have collected on the inner surface 214 of the conduit 204 in the region of the magnet 208.

To test for corrosion, the device 202 is moved with respect to the conduit 204. As shown in Figure 2c, when the holder 206 is moved in a downwards motion with respect to the conduit 204, the magnet 208 remains held against the outer surface 210 of the conduit 204 in the region where the ferromagnetic particles 212 have collected on the inner surface 214 of the conduit 204. This provides an indication to the user that the system has corroded.

As noted above, in the more advanced stages of corrosion, the ferromagnetic particles may be present in the system in the form of a layer coating the inside surface of the conduit. In such cases, the device 202 may be applied to the conduit, as described above and shown in Figures 2a to 2c and the holder 206 may be moved immediately, to release the magnet 208. A coating on the inner surface of the conduit is indicated by the magnet 208 remaining in position.

Claims

CLAIMS1. A device for detecting corrosion in a central heating system having a conduit formed from a non-magnetic material, the device comprising: a magnet for attracting ferromagnetic particles within the conduit; a holder for releasably holding the magnet and for mounting the device to the conduit; and wherein in use the magnet is releasably held against or adjacent the outer surface of the conduit by the holder.
2. The device according to claim 1, wherein the magnet is formed from or comprises iron, nickel, cobalt or alloys thereof.
3. The device according to either of claims 1 or 2, wherein the magnet has 15 a weight of up to 20 grams.
4. The device according to claim 3, wherein the magnet has a weight of up to 5 grams.
5. The device according to any preceding claim, wherein the magnet has a magnetic moment greater than 10,000 Gauss.
6. The device according to claim 5, wherein the magnet has a magnetic moment of up to 1000 Gauss.
7. The device according to any preceding claim, wherein, in use, the holder is moveable with respect to the conduit and wherein movement of the holder causes the magnet to be released.
8. The device according to claim 7, wherein the holder is slideable along the conduit, to release the magnet from the device.
9. The device according to either of claims 7 or 8, wherein the holder is rotatable around the conduit, to release the magnet from the device.
10. The device according to any of claims 7 to 9, wherein the holder is arranged to be partially or fully removed from the conduit, to release the magnet from the device.
11. The device according to any of claims 1 to 6, wherein the holder is fixedly attachable to the outer surface of the conduit.
12. The device according to claim 11, wherein the holder comprises a body and a retaining member, for retaining the magnet against or close to the outer surface of the conduit.
13. The device according to claim 12, wherein the retaining member is moveable with respect to the body, such that the magnet can fall or be displaced by gravity, when the retaining member is moved with respect to the 15 body.
14. The device according to any preceding claim, wherein the holder comprises a housing to retain the magnet.
15. The device according to claim 14, wherein the housing forms an enclosure around the magnet.zo
16. The device according to claim 15, wherein the enclosure is transparent.
17. A method for detecting corrosion in a central heating system having a conduit formed from a non-magnetic material, the method comprising: releasably holding a magnet against or adjacent to the outer surface of the conduit for a test period; and releasing the magnet at the end of the test period, such that it is able to fall or be displaced under gravity; wherein movement of the magnet under gravity provides a positive indication that there is no or undetectable corrosion in the system.
18. The method according to claim 17, wherein the test period is up to a 5 week.
19. The method according to claim 18, wherein the test period is up to an hour.
20. The method according to claim 19, wherein the test period is up to half an hour.
21. The method according to any of claims 17 to 20, wherein the magnet is released several times during the test period.
22. The method according to any of claims 17 to 21, wherein a device according to any of claims 1 to 16 is employed.
23. A kit of parts for detecting corrosion in a central heating system having a conduit formed from a non-magnetic material, the kit of parts comprising: a device according to any of claims 1 to 16; and one or more additional magnets.
24. A device for detecting corrosion substantially as hereinbefore described having reference to the accompanying figures.
25. A method for detecting corrosion substantially as hereinbefore described having reference to the accompanying figures.