Improved hygiene of an eco-friendly boiler

Abstract

An eco-friendly boiler is disclosed. The boiler comprises a water tank 30, one or more nozzles 40 configured to spray water into a spray chamber and one or more microwave generators 10 which emit radiation towards the water emerging from the spray nozzles. The nozzles produce a plurality of droplets or mist, which is then heated when they are exposed to the generated microwaves within the boiler. A source of ultraviolet (UV) radiation 90 emits radiation into the chamber. Bacterial, fungal or microbial growth is still possible, even when utilising microwave heating, as quiescent points occur within the chamber (areas with low microwave intensity). The use of an ultraviolet light source within the chamber mitigates this. The boiler may comprise two water tanks, one configured to supply hot water and the other configured to supply central heating. The disclosed boiler is an alternative to gas boilers, having a lower power consumption and a reduced carbon footprint.

Description

The present invention relates to improved hygiene of an eco-friendly boiler so is to make the boiler safer whilst making most efficient use of microwaves for the heating of water in a heating boiler, such as for use in providing hot water and central heating. Background The concept of using microwaves for the heating of water is well established, such as disclosed in CN107388217A, CN204388336U, US4288674A which disclose water heating apparatus wherein the water is heated by means of microwaves. WO8801826A1 discloses a central heating boiler for use in domestic and office systems wherein what is heated by means of microwaves for distribution to space heating radiators. Recent developments such as disclosed in GB 2608875Ato the same inventor has provided a more practical arrangement for microwave heating of water such as for use in hot water and central heating together. However ongoing development has shown that some unforeseen problems have arisen regarding potential hygiene. There is therefore room for optimisation of the basic system, particularly with regards suppression of fungal and bacterial in what is effectively a closed system. One of the advantages for microwave heating is that high local energy intensity is achieved and therefore inherent sanitisation of the system is expected. The possibility for fungal and bacterial growth in an environment saturated with microwaves is considered unlikely. However, in practice this is not proven the case and it is therefore a need for an improved system. The present invention The present invention in its various aspects is as set out in the appended claims. The present invention provides an eco-friendly boiler comprising, a water tank, wherein a portion of the water tank comprises a spray chamber, one or more spray nozzles configured to spray water into the spray chamber of the water tank and one or more microwave generators coupled to the spray chamber and configured to emit microwaves towards the water emerging from the spray nozzle or nozzles, which represent known features; further the present invention provides that a source of ultraviolet radiation is also directed into the chamber. As mentioned in the background, enclosure in which microwave energy is present at high levels is not expected to be subject to bacterial, fungal or other microbial growth. However, surprisingly it is been found that such growth is nevertheless possible. There is therefore unexpectedly a need for such a solution. This solution can be provided in the form of an ultraviolet light source within the chamber. Without wishing to be bound by theory because microwaves have a wavelength in the order of centimetres then it is possible for quiescent points to occur within a chamber, i.e. points at which the intensity of microwave energy is very low. Whilst in principle this could be overcome by providing a movable microwave energy source, in practice this is not practical and therefore with a fixed point-source of microwave energy such quiescent points arise. Whilst in a sealed system for central heating this is in principle not a problem, there is still the potential for the growth of bacteria such as legionella this is clearly an acceptable risk. In the provision of hot water (i.e. is delivered by a tap) then the problem is more direct as once the system has been contaminated it is very difficult to decontaminate. In considering solutions to the problem, on the basis that quiescent points are present then one potential solution was the provision of a further microwave source, therefore the potential for quiescent points of microwave energy would surely be reduced. Unfortunately, this was found in practice to make the situation worse. Again, not wishing to be bound by theory it is hypothesised that points at which the microwave energy overlaps gives rise to points of interference in electromagnetic energy providing places in the volume of the chamber, in particular on the walls, were there is effectively no microwave energy due to destructive interference. The invention therefore provides that the boiler comprises a plurality of microwave generators in addition to the source of microwave energy. Is been further found that having a plurality of ultraviolet light sources is not actually detrimental even though the same interference can be expected. However, in the present invention there may preferably be a plurality of ultraviolet light sources, wherein the chamber has a plurality of walls and the sources are placed on different walls. This gives the potential for more even illumination and therefore more even light intensity. The ultraviolet light source may be of any conventional source used for sterilisation. The ultraviolet radiation acts to destroy pathogens and other unwanted life. A conventional source of Ultraviolet radiation for sterilisation is a mercury-vapour lamp this has the benefit of providing broad-spectrum Ultraviolet radiation although with a strong emission line at 254 nm. H In the present invention a light-emitting diode or diode source of ultraviolet radiation is preferred. Specifically, a UV-C producing LED is preferred. Preferred wavelengths are: 255nm, 265nm, 275nm, and 285nm. More preferred are 255nm, 265nm as these are around the optimum frequency for germicidal activity. Most preferred is a combination of LEDs being a combination of LEDs with more than one frequency of admission. As bacteria vary in their susceptibility to ultraviolet light of a given wavelength. In this, referred is a combination of LEDs of with 255nm, 265nm wavelengths, preferably in a power emission ratio of 1:2 to 2:1. The ultraviolet light source of the present invention preferably provides the radiation intensity of between 10 and 90, preferably between 20 and 60, most preferably from 35 to 45 mJ / cm2 Ultraviolet radiation intensity. Due to the power constraints, particular of domestic electrical supply, the boiler of the present invention is properly configured to alternately irradiate the chamber with UV and ultraviolet light. This is been found to be sufficient to prevent bacterial growth. This matter is preferred where the boiler chamber is for the production of central heating water. A preferred form of the present invention provides the eco-friendly boiler comprising, a water tank, wherein a portion of the water tank comprises a spray chamber, one or more spray nozzles configured to spray water into the spray chamber of the water tank and one or more microwave generators coupled to the spray chamber configured to emit microwaves towards the water emerging from the spray nozzle or nozzles, that the spray nozzle or nozzles and further the present invention provides that at least one spray nozzle is directed in the same direction as the incoming microwaves and further comprising the ultraviolet light source directed within the chamber. By the same direction principal axis of the direction of emission is the same, such as defined from the point of origin to the centre of intensity of diffused radiation / water away from that point of origin creating a notional principal axis. Previously it had been considered that the spray should be perpendicular to the incoming microwaves so the microwaves will encompass the largest volume of water. However, it was generally found that this heated one side of the spray from the nozzle and the side remote from the microwaves was less well heated. Further in the present invention it is preferable that the spray nozzle or nozzles is in close proximity to the incoming microwave source. This enables the microwaves to impinge highest density of water whilst the ongoing generation of spray enables residual microwave energy to be absorbed before the microwave energy hits the sides of the water tank, work reflection is never perfect and therefore energy losses can occur. It also allows for a more compact design of boiler which can be important particularly in domestic settings. By close proximity this can be best measured in terms of wavelengths of the microwaves as this is the defining characteristic relating the water injected from the nozzle and the microwaves being emitted and any potential overlap giving constructive interference. Close proximity may therefore be defined as being between 0.1 and 3 wavelengths, more preferably between 0.25 and two wavelength separation between the nozzle on the microwave or microwave sources. The separation between adjacent microwave sources of a plurality, particularly two microwave sources may preferably be defined as defined as being between 0.2 and 3 wavelengths, more preferably between 0.5 and 3 wavelength separation. Most preferably the spray nozzle is located equidistant from the microwave sources. The sources may be defined by the point of emission of the microwave / water. Even more preferably the spray nozzle is located on a line defined between the points of emission of the microwave sources. Still further in the present invention it is preferable that the spray nozzle or nozzles is located between two incoming microwave sources of identical or near identical wavelength. This has the advantage that microwaves can constructively interfere and produce a localised high intensity of microwave energy, often to the extent that steam may be produced more or less instantly. Such steam serves to distribute heat to surrounding water droplets quickly and efficiently. This feature is greatly facilitated if a solid-state microwave sources used as magnetrons provide both relatively broader spectrum microwaves and can deviate in wavelength distribution / peak wavelength over time and therefore interference patterns may change in reliably and unpredictably. When two incoming microwave sources are used in the present invention then those sources are preferably configured that the overlap of the microwaves gives constructive interference in the path, such as defined by a principal axis of the outgoing spray of at least one spray nozzle. This concentrates the increased intensity microwave energy on the outward spray. As previously mentioned, the principal axis of the microwave energy, such as in this case the two incoming microwave sources is preferably parallel to that of the water sprayed from the spray nozzle. In this form of the invention the outward spray of the spray nozzle or nozzles is preferably directed to being of a, for example, cone angle of between 10 and 55 degrees. This produces a less diffuse jet and therefore more concentrated on the constructive interference region. Given the typical wavelength of microwave energy suitable in these applications then this angle also provides for a plurality of regions of constructive interference for a spray nozzle whilst providing a compact design. The most preferable cone angle is between 30 and 50 degrees. It will be appreciated that the edges of a cone of spray are not precisely defined and there will always be occasional droplets and much wider angles however the range relates to 90 percent, preferably 95 percent of the emitted water falling within the range from the principal axis to the outermost angle of the cone. i.e. the line defined between the slant out of the cone and the vertex of the cone. The slant height is the distance from the apex (point at the top) of the cone to any point on the circumference of its base. It is essentially the hypotenuse of a right triangle formed by the slant height, the radius of the base, and a segment from the apex perpendicular to the base. The use of constructive interference is particularly applicable to microwaves as they have a wavelength in the range 1 to 15 centimetres and therefore accurate positioning relative to the wavelength between the microwave source and the nozzles is eminently practical. The preferred wavelength for use in the present invention is between 2 and 13 centimetres, most preferably between 3 and 6 centimetres. These allow progressively more frequent, in terms of distance relative to the size of the tank, there is an overlap to create constructive interference. The most preferred wavelength (and these wavelength ranges and optimum wavelength are to be read in conjunction with the other features of the invention defined in terms of wavelength is 4 to 5 centimetres. Microwave emitter or emitters of the present invention preferably emits microwaves in one or more of the following frequency bands 915 + 13 MHz, 2450 ± 50 MHz, and 5800 ± 75 MHz. This is more readily inaccurately achieved using a solid-state microwave source as opposed to magnetron which can typically have a frequency spread of a range such as 70 MHz. The 5800 ± 75 MHz frequency range is preferred as this gives relatively closely spaced interference maxim up making best use of available space within a boiler. The 2450 ± 50 MHz, and more preferably the 915 ± 13 MHz, frequency range of referred where a magnetron is used as the microwave source as the instability of frequency of the microwave means that the deviation in frequency overtime, such as caused by temperature changes, as the least disruptive effect in terms of spatial presentation of the interference maxim relative to a spray nozzle. The preferred form of microwave generator is a solid-state microwave generator. The solid-state microwave generator may be of any conventional sort, solid-state microwave generator is a semiconductor-based microwave source. Suitable solidstate microwave sources are Tunnel Diode, Gunn Diode, Read Diode, IMPATT Diode, BARITT Diode, TRAPATT Diode, Varactor Diode. An example being: a GaN-based solid-state microwave generator (RIF58800-20SG, of RFHIC Co., Anyang, South Korea, minimum frequency 5725 megahertz, maximum frequency 5875 megahertz, output power 800 watts operated 50 volts DC. It is noted that the maximum and minimum frequencies of solid-state microwave generators represent controllable peak levels not a distribution, as is the case with the magnetron. However, a magnetron microwave generator is also applicable to the present invention such as an equivalent magnetron 2M261, Panasonic Co., Tokyo, Japan the solid-state device gave a more stable microwave frequency and the region in which constructive interference occurred was stable over a period during the period of observation, being several minutes. This was also observed with different throughput rates of water spray. The microwave generator may be water cooled and the cooling water fed to the output spray for maximum energy efficiency. This reduces the amount of heat to the year or general structure of the boiler due to heat dissipation from the microwave generator. This combines with the aforementioned features to give the preferred higher energy efficiency. Drawings The present invention is illustrated by means of the following drawings in which like features are designated with like numerals. The figures provide Figure 1: shows exploded schematic view of the components used to form the claimed invention Figure 2: shows a schematic example boiler of the claimed invention. Figure 3: shows a schematic example boiler of the claimed invention with different UV generator location. Figure 4: shows a schematic example boiler of the claimed invention with different UV generator location. Figure 5: shows an example boiler as per the present invention, which uses a two-tank system. The features of the drawings are listed as follows: 10 - Microwave generators 20 - Shielding layer 5 30 - Water tanks 40 - Spray nozzles 50 - Pumps 60 - Step-up transformer (if required) 70 - Outer casing / housing io 72 - Front panel 90 - UV generators 101- Microwave (notional peak intensity of outgoing wave) 111 - Line of Constructive Interference defined by overlapping peak intensities 121 - Constructive Interference 15 131 - Water Spray Cone 135 - Water droplet Detailed description referring now to the aforementioned figures. The claimed invention provides a microwave heated boiler comprises the following components, as depicted in figures 1,2, 3 and 4. Microwave (MW) generators 10: the invention utilises two or more microwave generators, 10 as a means of heating the water inside the boiler tank 30, as the water absorbs the microwaves. More specifically the microwaves are used to heat the water as it enters the boiler tank 30, as the water would preferably enter the boiler as a mist or spray of droplets, these droplets increase the total surface area of the water, thereby increasing the probability of the microwaves being absorbed. The microwave generators 10 are couple to the side of the water tank in between the microwave generators 10. The microwave generators 10 may be in the form of a magnetron, or a solid-state microwave generator, of these options the solid-state generator would be preferable as they are able to produce the same amount of radiation as the magnetron using less power. Further, the wavelength of the microwaves emitted by the solid-state generator is more stable, accurately producing the desired wavelength of microwaves. While the remaining sides may be encased in a layer of shielding 20, to help prevent the generated microwave from leaking into the surrounding environment, by including both the emitter and the shielding, the microwave generated by each generator can be directed into the boiler tanks with no risk of escaping to the boiler’s surroundings. In operation the microwave generators 10 may be able provide continuous heating, changing the intensity, and / or amplitude, of the microwaves generated in order to control the temperature of the water in the tank 30, for example a lower intensity being used for lower temperatures, or may instead operate periodically activating to raise the water temperature to a desired value before deactivating again, in this mode it is likely that the microwaves will be generated at a higher intensity / amplitude to heat the water rapidly. It is noted that regardless of the mode used, this method of heating water provides a greener alternative to current gas boilers, and may require less power to operate compare to electric water heating. In some cases, the power from a standard wall outlet may be sufficient to run the two or more microwave generators 10 attached to the boiler, in other cases the boiler may come with its own power supply, such as a solar panel, regardless of the method used the claimed boiler does not require a large amount of power to operate. Additionally, as the microwave generators 10 do not produce any emissions, therefore the microwave boiler is more eco-friendly and also does not need to be ventilated, meaning the boiler does not need to be mounted to an external wall, and can instead operate from anywhere in the home with a suitable power supply. Additionally, the boiler may be configured to generate high pressure steam, said steam may be used when the boiler is powered by a turbine as a means to keep said turbine turning in an emergency, wherein power to the turbine is interrupted / lost. In these cases, the boiler is configured to pump a portion of the heated water back through the spray nozzle, thereby exposing this portion of water to additional heating, in order to further heat the water to produce steam. Note that in some cases the heated water may be pump to a secondary tank, or a secondary spray chamber, inside which it will be heated again to form steam. In some cases, the secondary tank / spray chamber may be smaller so as to increase the pressure of the steam held within. These embodiments may also cycle the portion of heated water through the spray nozzles of the main or secondary tank / spray chamber multiple times in order to heat the water to the sufficient temperature to produce a sufficient quantity of steam. As this steam will only be needed in emergencies it is preferable to have the ability to store the steam until it is needed, additionally if the steam is stored within the same tank as the heated water the steam may interfere with the heating process as the steam may become dense enough to shield the droplets that are sprayed into the water tank. For these reasons it would be preferable to include the secondary tank to store the steam until it is needed, note that this secondary tank may continuously cycle the portion of water fed into the tank so as to constantly heat this portion of water to prevent it cooling / condensing. The high pressure and temperature of the steam mitigates against the incubation of life. The two or more microwave generators 10 may also be part of a microwave generating unit. Wherein each unit comprises the two or more microwave generators 10, with shielding 20 and an emitter for each generator, the units may also comprise control systems for each of the generators 10 to control the output of the emitters, such as changing the magnitude, or intensity, of the emitters’ output, or change the emitters’ modes from a constant output to a pulsed output. It is noted that the constant wave output would allow the boiler to constantly heat the water within the boiler, providing a means to heat the water after it is pooled within the bottom of the water tank 30, however the intensity of the microwaves will be relatively low compared to the pulsed output so the rate of the temperature increase within the water, and therefore the heating process, may be slower when compared to the pulsed output. Whereas the pulsed output provides short intense bursts that may provide a faster rate of energy absorption, and therefore a faster heating process, but may be less penetrative than the constant wave, meaning the pulses may be less effective at keeping the water in the water tank 30 warm as it cannot penetrate the pooled water. As both modes have their own benefits the user may choose the mode they find most desirable, or in cases where the boiler includes multiple Microwave generators 10, the user may set different generators to different modes, to gain the benefits of each. The units may also include one or more sensors for monitoring the generators 10 which may detect faults in the unit, fans for cooling the generator components to prevent overheating, and / or a power input for powering the components of the unit, which may allow the unit to be disconnected from the power source in order to be safely removed it from the boiler, during maintenance or when a fault is detected by the sensor. It should also be noted that instead of air-cooling the MV generators 10, the units may include a water-cooling systems or other suitable cooling systems, like those found in computers. However, one embodiment of the cooling system may use the water flowing into the water tank 30 as the cooling medium within the cooling system. Preferably this water would pass over the microwave units just before being sprayed into water tank 30, as this is likely when the water is at its coolest temperature, meaning the temperature difference between the water and the components of the generator units will be at its greatest, this higher temperature gradient may improve the rate of heat transfer between the unit and the water, thereby allowing more heat to be transferred to the water. Such a cooling system will also help in improving the efficiency of the water heating process within the boiler by using the microwave units to pre-heat the water before entering the water tank 30, as the process of heating the water with microwaves is not dependent on a heat gradient this pre-heating would not lower the rate of energy transfer within the tank, but may help bring the water to a higher temperature. It should also be noted that a benefit of using such units, is that should a unit fail, it can be easily removed and replaced with a working unit, after which the faulty unit may be disposed of, or sent to be repaired. Making it easier for the user to do repairs to the boiler when necessary, and means the user does not need to go for long periods of time without hot water, while waiting for repairs. The UV generators likewise being in units with such advantages. Spray nozzles 40: to improve the effectiveness of the microwave generator-based heating the boiler may utilise one or more spray nozzle 40. Wherein the nozzles 40 are configured to spay the water entering the boiler tank 30 to form droplets, or a fine mist, which can then be heated by the microwaves, after which the heated water pooling together at the bottom of the boiler tank 30 ready to be used. This process helps to improve the effectiveness of the microwave hearting, as each droplet is a separate volume of water which will require significantly less energy to heat, these droplets also increase the amount of surface area that is exposed, thereby increasing the chances of the generated microwaves being absorbed. This is especially true, when compared to a system that tries to heat all of the water in the tank at once, as the greater volume would mean more energy is required to heat the water to a desired temperature, increasing the power consumption of the boiler. Additionally, when the water is pooled at the bottom of the tank, the microwaves may only be able to penetrate a certain depth of the water, as the water at the top of the tank may be shielding the water beneath, meaning that only the top of the water is being heated, and the rest of the water would be heated slowly via convection currents, which would mean the process of heating the water in the boiler to a desired temperature would take significantly more time. Therefore, by heating a spray of water, the water in the boiler can be heated faster, and would require less energy to reach the desired temperature. Note that is may also be possible to have the microwaves continue to heat the sprayed water once it has pooled at the bottom of the tank, but as the water is already heated this process would be more efficient due to the lower temperature difference between the sprayed water and the pooled water. The pooled water could also have UV radiation emitted at it, for sterilisation. Microwave generators 10, the spray nozzle 40 may be mounted to the sides or top of the tank 30, though it is noted the nozzles 40 should preferably be in a position perpendicular to the position of the microwave generators 10, as this may help improve the overlap between the emitted microwaves and the water flow from the nozzle. Thereby improving the efficiency of the heating process, by ensuring the largest possible volume of the sprayed water is exposed to the generated microwaves. It is noted that different types of nozzles may be utilised to get different spray patterns, for example, the nozzle 40 may be configured to produce a flat splay, thereby shaping the water into a thin sheet to again improved exposure to the microwaves, as the thin sheet ensures the microwaves can fully penetrate the sprayed water. In some cases, the nozzles 40 may produce a course flow, for though a course flow would spray the water in a larger volume, which runs the risk of the microwaves not fully penetrating the sprayed water, such a flow may help to bypass, or remove any blockages with the nozzle itself. Thereby providing the boiler with a means of removing any blockages that form, without the need to remove the nozzle from the boiler. In some cases, the nozzles 40 may be configured to produce a cone spray, such a spray would also ensure that the water enters the boiler tank as a thin layer for improved penetration, but would potentially also inject a greater volume of water at once providing a more efficient flow, this flow would be preferably when the water is sprayed from the top of the tank, in such cases microwave generators 10 may be mounted on opposite sides of the flow, to help ensure that one side of the cone does not block the microwaves from the other side of the water flow. And in some embodiments the nozzle 40 may be configured to produce a fine mist, thereby reducing the volume of the water droplets in the flow, and increase the surface area of the droplets, thereby further reducing the energy needed to heat them, though such a mist may cover a large volume, or be so dense, to the point where the droplet furthest from the microwave generators 10 may not be heated in time, as it is shielded by the rest of the mist. It is, noted that in any case, it is important that as much of the surface area of the sprayed water is exposed to the microwaves as possible, as there will be little to no convection to transfer heat between the droplets, and though this can be achieved by using high number of smaller volume droplets, with little spacing between them, there must be a balance to ensure the droplets do not shield one another from the microwaves, therefore it is preferred that the spray chamber / portion of the water tank that received the water from the nozzle houses a relatively low volume of water at a given time, therefore it may be considered that the flat or cone spay may be preferable as the shape of the flow ensures there is little to no shielding between droplets, though at a low pressure the mist spray may be preferable as it produces the smallest droplets and therefore exposes the largest surface area. Regardless of which nozzle design is used, it is noted that the nozzles 40 would preferably be towards the top end of the water tank 30, in order to increasing the path, the sprayed water has to travel before reaching the pool of water at the bottom of the tank. In doing so, the boiler may increase the likelihood of the sprayed water being heated before pooling with the rest of the water, as the droplets or mist will be exposed to the microwave for a greater time, thereby increasing the probability of the individual droplets absorbing sufficient microwaves to be heated by the time it reaches the bottom of the water tank. It is also noted that the water tank 30 should not be completely filled with water, as if it was there would be no room to produce the desired spray described above. Additionally, when there is more open space within the tank 30, there will be a longer path the sprayed water will need to travel before reaching the pooled water, therefore the more space in the water tank the higher the probability that the generated microwaves will be absorbed by a water droplet, for this reason it may be preferable to have the water tank be no more than half full at any given time. Alternatively, the water tank may include a separate spray chamber, wherein the spray nozzles 40 spray water into the spray chamber to be heated before the heated water flows into the water tank 30. Pumps 50 and water tanks 30: the boiler may also comprise one or more pumps 50 for pumping the water in and out of the boiler, similar to most boiler designs. However, in most traditional boilers the pumps used are design to output a large volume, typically with a lower pressure output. Such pumps may not be suitable for the claimed system as the nozzles 40 will require a relatively high pressure to create the required spray. Therefore, the claimed boiler may use a high-pressure pump for pumping the water in and out of the tank. Alternatively, the boiler may use a plurality of pumps, which includes at least one low-pressure pump for pumping water round the system in a high volume, and at least one smaller high-pressure pump for pumping water into the spray nozzles 40 to increase the pressure of the water flowing to the nozzles 40, to ensure the nozzles can produce a fine spray, as the water enters the tank 30. In some embodiments the boiler may comprise a single water tank 30 as depicted in Figure 2, for receiving the heater water, to be stored before use, as previously mentioned this water tank 30 may also include a spray chamber for receiving and heat the sprayed water before storing the heated water in the water tank 30. But in the preferred embodiment the boiler of the present invention may comprises two tanks 30, as depicted in figure 3, one for producing hot water for water systems, such as taps and showers, and a separate tank for producing hot water for a central heating system. By using two tanks 30, the boiler can supply both systems simultaneously, without the need to priorities one system over the other, meaning that using hot water from outlets such as sinks and showers does not affect the central heating system, and vice versa. Note that in such a two-tank system the boiler will require at least two pumps 50, one for each tank 30. And in some embodiments, there may be a need for four pumps, comprising a low-pressure pump for moving a large volume of water through the respective system, and a smaller high-pressure pump for pumping water through the spray nozzles 40 of each tank 30. Each water tank may have one or more UV generators 90. Additionally, it is noted that each tank 30 used in the disclosed boiler should comprise a material that may either absorb or reflect the generated microwaves, or may have a coating on the inside of the tank made from such materials, so that the generated microwaves do not escape the tank 30. It is noted that by using the reflective material the microwaves may be reflected back towards the water in the tank 30 to improve the efficiency of the heating process, by exposing more of the water to the generated microwaves, thereby increase the chance of the microwave being absorbed. However, as mentioned the casing, or the inner lining, may be made of a material that will absorb the microwaves instead, this will result in the casing of the water tank 30 heating up, and may therefore provide heat to the water in the boiler, especially to the pooled water that the microwaves may not be able to penetrate. In the cases wherein the tank 30 is made of a material that absorbs the excess microwaves, the boiler may comprise a series of pipes that pass the water over the sides of the tank 30 before it reaches the spray nozzles 40, this way the water can absorb heat from the tank to pre-heat the water before it enters the water tank, this can prevent the tank 30, from overheating and improve the heating process by reducing the time / energy needed to heat the water to the desired temperature. Also as mentioned the claimed boiler requires the water entering the boiler to be sprayed into droplets, or a mist before being heated by the microwaves, therefore the one or more water tanks 30 may requires a spray chamber, this may be a portion of the water tanks volume, or a separate chamber that then feeds the heated water into the water tank. As previously mentioned, it is preferable for the boiler to have a means of keeping the water warm after it has pooled in the water tank, usually by having the water tank exposed to the generated microwaves, therefore of these options it is preferable that the spray chamber be part of the water tank 30 itself. In particular the water tank can be seen more as a canister wherein only a portion of the water tank 30 will be filled at a given time, the empty portion of the water tank will be coupled to the spray nozzle and will act as the spray chamber. To achieve this the water tank 30 would preferably only hold enough water to fill about half the tank or less, when the water pools at the bottom of the tank, wherein the spray nozzles will spray the droplets or mist into the empty top half of the chamber to be heated by the microwaves. It should also be noted that when a spray chamber is used it may be preferable for the spray chamber to be made of, or lined with a material that can reflect microwaves, allowing the unabsorbed microwaves to be redirected towards the sprayed water, to increase the chance of absorption. This also can be done for UV. It should also be noted, that each of the pumps 50 and tanks 30 used in the boiler may be design to couple with a range of different water pipes. Allowing the user to maintain the pipes to their current boiler, and simply couple them to the new tank 30 / pumps 50, when installing the claimed boiler, thereby allow easy installation. It should also be noted that similar to the microwave generators 10, the pumps 50 and water tanks 30 may comprise their own units that can be easily coupled to, or removed from, the boiler, and therefore may be easily replaced if they are faulty. Power supply: In order to use the above-mentioned pumps 50 and microwave generators 10 the claimed boiler requires a power supply. In some embodiments this power may be supplied from a standard wall outlet, which feed electricity into a step-up transformer 60, which may be mounted within the boiler, that will then output the required power to the pumps 50 and microwave generators 10. Note that in embodiments wherein the boiler has multiple tanks 30, there may be a separate transformer 60 for each tank 30, each supplying power to the pumps 50 and microwave generators 10 of their respective tanks 30. In other embodiments the boiler may have its own power supply, such as a solar panel, that may also feed power into a transformer 60 within the boiler before powering the pumps 50 and / or MM generators 10, though such external power supply may be able to generate the necessary power for the boiler without the need for the above-mentioned transformers 60. In some cases, the boiler may be powered by a turbine, in such cases as previously mentioned the boiler may be configured to produce steam in order to turn the turbine in the case of an emergency, when power has been interrupted or lost, until the power returns to normal, this system may require an additional tank / chamber for storing and generating said steam. Outer casing / housing 70: the boiler should preferably include an outer casing / housing 70 which would house the above-mentioned boiler components, such a housing 70 may help make the boiler more aesthetically pleasing, and may also prevent water leaking from the boiler from entering the external environment, should one of the tanks 30, nozzles 40 or pipes within the boiler begin to leak. This outer casing may also be made from a material that could shield the surroundings from the microwaves generated by the microwave generators 10, by being made from a material that can absorb such microwaves, or a material that may reflect the microwaves back towards the water tanks 30. The housing 70 may instead have a lining on the inside of the housing 70 made of a material that can absorb the microwaves or reflect them back towards the water tank 30, using such a lining may help to reduce the overall weight of the housing 70, when compared to an entire housing made from the same material. It should be noted that the housing 70 may be removeable, or have a removable font panel 72, to allow the user to access the different components within the housing more easily. Control system: The boiler features a control system that may be coupled to boiler, remote from the boiler, or preferably a combination of both, thereby providing additional redundant control means should one of the control systems fail. The claimed boiler may feature a display mounted to the water tank 30 or housing 70, to show the status of the boiler, as well as controls coupled to the display, or the surrounding housing, for controlling the water temperature and water levels within the tank 30. It is noted that these controls may also be remote from the boiler itself. In these cases, the controls may comprise a mobile hub or controller, that would comprise the above-mentioned display and boiler controls, which can control the boiler remotely, possibly through a Wi-Fi connection, or internet of things (loT) connection. In other cases, the mobiles controls may be in the form of an application on the user’s mobile devices, such as a smartphone, smartwatch, laptop. These mobile control systems will allow the user to monitor and control the boiler regardless of their current location, though the boiler may as mentioned still have manual controls on the boiler itself as a backup control system. The UV generators 90 can likewise be adjusted. Also, in systems that utilise generator units with monitoring sensors, the control system may also be configured to alert the user to any detected faults within the microwave generator units, and may also be configured to control the outputs of the MV generators 10 and / or generator units. The UV generators 90 can likewise be monitored. By using the above-mentioned boiler system, the claimed invention provides an eco-friendly alternative to gas boilers. By using microwave generators to heat the water within the boiler, wherein the microwave generates uses electricity and have a low power consumption, the boiler does not produce carbon emissions and has a reduce carbon footprint when compared to other gas boiler alternatives. The two microwave emitters 10 produce a two-point source interference pattern, creating lines of constructive and destructive interference. The lines of constructive inference are positioned to be in the centre of the water. The microwave generators 10 generate microwaves 101. The UV generators 90 generate UV-waves. The water spray nozzle sprays water. The water that the water spray nozzle sprays is sprayed into water droplets 135. The water droplets 135 occupy an area. The area occupied by the water droplets 135 is the shape of a cone. The area occupied by water droplets 135 that is the shape of a cone is the Water Spray Cone 131. The inference patterns of the microwaves 101 from the microwave generators 10 creates and inference pattern which includes constructive interference 121 which is strongest on a Line of Constructive Interference 111. One or more lines of Constructive Interference 111 are in the Water Spray Cone 131. The energy of the microwaves on the line of constructive interference 111 in the Water Spray Cone 131 heats the water of the water droplets 135 in the Water Spray Cone 131. Thus, the boiler heats water. In the present invention the location of the spray nozzle 40 is primarily defined by the outlet of the spray nozzle 40. The location of the spray nozzle 40 dictates the desirable location of the UV generator 90. In the present invention the location of the microwave source is primarily defined by the points of emission of the microwaves from the microwave source. If you microwave source has an area from which microwaves are omitted then the location of the microwave source can be defined by the centre of that area. In one permutation the UV generator 90 or UV generators 90 can be located on the side of the water tanks 30. The the UV generator 90 is aligned to areas of the water tanks particularly vulnerable to incubating unwanted life. The UV generator 90 can be placed on the side of the water tank at distance from the microwave generator aligned with. The UV generator 90 can be located on the face of the water tanks 30, perpendicular to the microwave generator. This placement can be aligned with a microwave intensity or lack of intensity particularly vulnerable to incubation of unwanted life. In another permutation the UV generator 90 can be located on the face of the water tanks 30, facing towards the microwave generator. This allows the two to have the same central axis, each filling the water tank with radiation. In another permutation the UV generator 90 can be located on the face of the water tank 30, facing in the same direction as the microwave generator. Allowing the generator to be constructed as a single unit, sharing electronics. This also mitigates the microwave generator 10 heating and causing damage to the UV generator. The UV generator 90 can be located on the face of the water tanks 30, perpendicular to a spray nozzle 40. This placement allows all water emitted from the nozzle 40 to, after travelling out of the nozzle 40 be irradiated with UV.

Claims

7 24Claims1. An eco-friendly boiler comprising, a water tank, wherein a portion of the water tank comprises a spray chamber, one or more spray nozzles configured to spray water into the spray chamber of the water tank and one or more microwave generators coupled to the spray chamber and configured to emit microwaves towards the water emerging from the spray nozzle or nozzles, wherein a source of ultraviolet radiation is present for emitting ultraviolet radiation into the chamber; and further comprising in use constructive microwave interference.

2. The boiler of claim 1 further comprising a plurality of ultraviolet light sources.

3. The boiler of claim 1 or claim 2 where the source of ultraviolet radiation for sterilisation comprises a mercury-vapour lamp.

4. The boiler of any of claims 1 to 3 where the source of ultraviolet radiation for sterilisation comprises a light-emitting diode or diode source of ultraviolet radiation.

5. The boiler of claim 4 wherein the source of ultraviolet radiation for sterilisation comprises a UV-C producing LED.

6. The boiler of claim 5 wherein the source of ultraviolet radiation for sterilisation is configured to generate peak wavelengths at a wavelength one or more of 255nm, 265nm, 275nm, and 285nm.

7. The boiler of claim 6 wherein the source of ultraviolet radiation for sterilisation is configured to generate peak wavelengths at a wavelength both 255nm and 265nm.

8. The boiler of any preceding claim, further comprising a combination of LEDs being a combination of LEDs with more than one frequency of emission, in am in use power of emission ratio of from 1:2 to 2:1.

9. The ultraviolet light source of the boiler of any preceding claim with radiation intensity of between 10 and 90 mJ / cmA2 Ultraviolet radiation intensity.

10. The ultraviolet light source of the boiler of claim 9 with radiation intensity of between 20 and 60 mJ / cmA2 Ultraviolet radiation intensity.

11. The ultraviolet light source of the boiler of claim 10 with radiation intensity of between 35 and 45 mJ / cmA2 Ultraviolet radiation intensity.

12. The boiler of any preceding claim, wherein at least one spray nozzle is directed in the same direction as the incoming microwaves and further comprising the ultraviolet light source directed within the chamber.

13. The boiler of any preceding claim, further comprising a spray nozzle or nozzles in close proximity to the incoming microwave source.

14. The boiler of claim 13 wherein close proximity is defined as being between 0.1 and 3 wavelengths of the microwave radiation emiited by the microwave sources.

15. The boiler of any preceding claim, wherein the boiler comprise a plurality of microwave sources, further comprising the spray nozzle being located equidistant from the microwave sources.

16. The boiler of any preceding claim, further comprising spray nozzle or nozzles located between two incoming microwave sources of identical or near identical wavelength.

17. The boiler of any preceding claim, wherein the microwave source or sources is a solid-state microwave source or sources.

18. The boiler of any preceding claim, further comprising outward spray cone angle of between 10 and 55 degrees.09 07 2419. The boiler of any preceding claim, configured to generate a wavelength of the microwave radiation between 2 and 13 centimetres.

20. The boiler of claim 19 wherein the wavelength is 4 to 5 centimetres.21 .The boiler of any preceding claim further comprising a microwave emitter or emitters that emits microwaves in one or more of the following frequency bands 915 ± 13 MHz, 2450 ± 50 MHz, and 5800 ± 75 MHz.

22. The boiler of any preceding claim further comprising a solid-state microwave generator that is a semiconductor-based microwave source.

23. The boiler of any preceding claim further comprising magnetron microwave generator.

24. The boiler of any preceding claim further comprising the microwave generator water cooled and the cooling water fed to the output spray.

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