WO2018161098A2

WO2018161098A2 - An immersion heater

Info

Publication number: WO2018161098A2
Application number: PCT/ZA2017/050060
Authority: WO
Inventors: Andre Meinhard Fourie
Original assignee: Geyserwise Cc
Current assignee: Geyserwise Cc
Priority date: 2016-09-14
Filing date: 2017-09-11
Publication date: 2018-09-07
Anticipated expiration: 2019-03-14
Also published as: WO2018161098A3

Abstract

An immersion heater comprises at least one housing structure; at least one electrically connectable heat source being locatable in the housing structure; the housing structure being locatable inside a sealable enclosure; the sealable enclosure being locatable inside a heating container and attachable to the heating container; and the housing structure being removable from the sealable enclosure and the inside of the heating container while the sealable enclosure is locatable inside the housing structure.

Description

AN IMMERSION HEATER

Technical field

The invention relates to an immersion heater. More particularly, the invention relates to an immersion heater for use in a heating container and a method of replacing an immersion heater in a heating container. Background art

An immersion heater used in a tank, vessel, vat or similar heating container converts electricity into heat through the process of resistive or Joule heating. Electric current passing through the immersion heater encounters resistance, resulting in heating of the immmersion heater.

Traditionally an immersion heater in a tank, vessel, vat or similar heating container uses metal resistance wire as the source of heat. Most metal resistive immersion heaters use Nichrome 80/20 (80% nickel, 20% chromium) wire, ribbon, or strip. Metallic resistance immersion heaters may be, for example, wire or ribbon, straight or coiled.

Ceraminc immersion heaters may also be used as apposed to metallic immersion heaters. Ceramic PTC (Positive Temperature Co-efficient) chips used as the heat source in a immersion heater provide a self limiting ability and thus a thermostat device is not generally needed alongside such a immersion heater to enable overheat protection as the overheat protection is inherent. The use of the PTC chips also provide an added energy saving opportunity as PTC chips provide a low wattage source of electric energy. PTC chips are manufactured from a barium-titanate material plus a few key doping materials added to provide the desired resistance/temperature characteristics. When electrical voltage is applied to a PTC chip, heat is not generated at a constant rate, rather as the PTC chip heats up it reaches a designed temperature at which the heat output decreases drastically and prohibits the immersion heater from gettting hotter. Thus, PTC chips have a designed temperature limit.

A hot water storage tank, also known as a hot water tank, thermal storage tank, hot water thermal storage unit, heat storage tank, hot water cylinder or storage water heater is a water tank that is used to store hot water for space heating, domestic use or commercial use. Tanks may vary in size typically with a storage capacity of from 50 to 10000 litres. Certain hot water tanks may have one or more electric immersion heaters to heat water. Normally tanks above a volume of 300 litres capacity may have a bank accommodating more than one immersion heater.

Hot water storage tanks used for washing, bathing, or laundry generally have thermostat controls to regulate the temperature, generally in the range of 40 to 80 °C, and are connected to the domestic cold water supply. Where the water supply has a high content of dissolved minerals such as limestone, heating the water causes the minerals to precipitate in the tank; a water tank may develop leaks due to corrosion after only a few years. Dissolved oxygen in the water can also accelerate corrosion of the tank and its fittings. Certain problems have arisen with current resistive immersion heaters used in hot water storage tanks. For example, premature failure has been observed due to hard water conditions being present. In some cases, the resistive immersion heaters in areas with hard water conditions have had to be regularly replaced due to the poor water quality. This poor water quality leads to scale build up and inefficiencies experienced in the electricity consumption during the heating of water by these hot water storage tanks. As an example of this, it has been found that an estimated 2 000 resistive immersion heaters for hot water storage tanks are replaced on a daily basis in South Africa.

A further problem is that there are premature failures of resistive immersion heaters due to materials used in these immersion heaters that are not suitable to the local water conditions and this also leads to inefficiencies in electricity consumption for the heating of the water in hot water storage tanks.

An even further problem is that there are cases when a water storage tank may run dry due to water shortages with many local municipalities imposing water cuts. This may cause the resistive immersion heaters in these tanks to burn out and they need to be replaced more often due to these conditions.

Most current hot water storage tanks include at least one flange mounted immersion heater and thermostat combination. This arrangement is currently the most common example in use for water storage tanks and they are found in approximately 90% of the market. These hot water storage tanks are required to be completely drained in order for an immersion heater to be replaced. It is a known fact that domestic hot water storage tanks are the biggest energy users in the domestic environment. Furthermore, it is also known that these tanks generally need to be drained substantially completely when its components such as an immersion heater are to be replaced. In a similar way, electric immersion heaters are also used in various other apparatus, such as, for example, in fryers, deep fryers, sterilising equipment, or the like. These immersion heaters also need to be replaced for various reasons during the lifetime of such apparatus. The invention provides a more efficient immersion heater which conserves both water resources when used in water heaters, or oil/fat when used in fryers, as well as energy in the event of the replacement of the immersion heater component in a heating container, such as a water storage tank, fryer, sterilising container, or the like. The invention also provides an easier replacement of these components than with prior existing examples. Disclosure of the invention

According to a first aspect of the invention there is provided an immersion heater comprising:

- at least one housing structure;

- at least one electrically connectable heat source being locatable in the housing structure;

- the housing structure being locatable inside a sealable enclosure;

- the sealable enclosure being locatable inside a heating container and attachable to the heating container; and

- the housing structure being removable from the sealable enclosure and the inside of the heating container while the sealable enclosure is locatable inside the housing structure. It will be understood that any contents locatable in the heating container is able to remain in the heating container while the housing structure is removable from the sealable enclosure and the inside of the heating container. This is due to the fact that the sealable enclosure remains inside the heating container during the removal. In one form of the invention the electrically connectable heat source includes at least one PTC chip, which is preferably connectable to insulated conducting wire. Further preferably the electrically connectable heat source includes a plurality of PTC chips.

It will be understood that "PTC" is an acronym for "Positive Temperature Coefficient."

The sealable enclosure preferably has a substantially elongate shape. In the same way, the housing structure also preferably has a substantially elongate shape. In this case the heat source may be made up of a plurality of PTC chips arranged in at least one substantially elongate structure.

In a further form of the invention the heat source is at least one metallic wire. In one form of the invention the immersion heater may be an AC (alternating current) immersion heater. In another form of the invention the immersion heater may be a DC (direct current) immersion heater.

In an even further form of the invention the immersion heater may be a dual immersion heater.

It will be understood that a dual immersion heater is both an AC (alternating current) and DC (direct current) immersion heater.

The sealable enclosure is preferably locatable in the heating container by means of a flange type or screw boss arrangement with the heating container. In the same way the housing structure is preferably locatable in the heating container by means of a flange type or screw boss arrangement with the heating container.

It will be understood that once the housing structure and the electrically connectable heating source have been removed from the heating container, they may be replaced. According to a second aspect of the invention there is provided a method of replacing an immersion heater in a heating container, the method comprising:

- removing at least one housing structure from location inside a sealable enclosure, the sealable enclosure being locatable inside a heating container and attachable to the heating container, at least one electrically connectable heat source being locatable in the housing structure, the housing structure being removable from the sealable enclosure and the inside of the heating container while the sealable enclosure is locatable inside the heating structure; and

- replacing the housing structure inside the sealable enclosure locatable inside the heating container while any contents locatable in the heating container is able to remain in the heating container. It will be understood that any contents locatable in the heating container is able to remain in the heating container while the housing structure is removable from the sealable enclosure and the inside of the heating container. This is due to the fact that the sealable enclosure remains inside the heating container during the removal.

In one form of the method of the invention the electrically connectable heat source includes at least one PTC chip, which is preferably connectable to insulated conducting wire. Further preferably the electrically connectable heat source includes a plurality of PTC chips.

In a further form of the method of the invention the heat source is at least one metallic wire.

In one form of the method of the invention the immersion heater may be an AC (alternating current) immersion heater. In another form of the method of the invention the immersion heater may be a DC (direct current) immersion heater.

In an even further form of the method of the invention the immersion heater may be a dual immersion heater.

It will be understood that a dual immersion heater is both an AC (alternating current) and DC (direct current) immersion heater. The sealable enclosure is preferably locatable in the heating container by means of a flange type or screw boss arrangement with the heating container. In the same way the housing structure is preferably locatable in the heating container by means of a flange type or screw boss arrangement with the heating container.

It will be understood that once the housing structure and the electrically connectable heating source have been removed from the heating container, they may be replaced.

Brief description of the drawings

The invention will now be described in more detail with reference to the accompanying drawings wherein:

Figure 1 shows a three-dimensional side view of an immersion heater, according to an embodiment of the invention;

Figure 2 shows three-dimensional through view of an immersion heater, according to an embodiment of the invention;

Figure 3 shows three-dimensional through view of an immersion heater, according to a further embodiment of the invention;

Figure 4 shows a sectioned view through A-A of the immersion heater of Figure 3;

Figure 5 shows a side view of a housing structure of the immersion heater of Figure 3;

Figure 6 shows sectioned view through B-B of the housing structure of Figure 5;

Figures 7a and 7b show an end side view and a side view, respectively, of a PTC chip from an immersion heater, according to an embodiment of the invention;

Figure 8 shows sectioned side view of the PTC chip of Figures 7a and 7b;

Figure 9 shows a sectioned end view of the PTC chip of Figures 7a and 7b;

Figure 10 shows a flange for use on a heating container, according to an embodiment of the invention;

Figure 1 1 shows a pictorial side view of an immersion heater located on the flange of Figure 10, according to an embodiment of the invention; and Figure 12 shows a pictorial top view of the immersion heater located on the flange of Figure 10.

Detailed description of the invention

A immersion heater 10, according to several embodiments of the invention, is shown in Figures 1 to 4. Immersion heater 10 comprises at least one housing structure 12 which is locatable inside a sealable enclosure 14. At least one electrically connectable heat source 16 is locatable in the housing structure 12.

The electrically connectable heat source 16 may be at least one metallic wire in a chosen configuration, according to one form of the invention, as is the case in various types of resistant immersion heaters used currently in hot water storage tanks or in fryers.

In another form of the invention, as shown in Figures 2 to 6, the electrically connectable heat source is at least one ceramic PTC chip 18 which is connectable to insulated conducting wire. Preferably the heat source is made up of a plurality of elongate ceramic PTC chips 18, arranged in a housing structure 12 that preferably has a substantially elongate shape, and which are connectable to insulated conducting wire.

The sealable enclosure 14 also perferably has a substantially elongate shape and is locatable inside a heating container (not shown), and is attachable to the heating container via a flange type arrangement, as shown in Figures 10 to 12, or a screw boss arrangement. The housing structure 12 is removable from the sealable enclosure 14 and the inside of the heating container, while the sealable enclosure is locatable inside the housing structure 12.

It will be understood that any contents locatable in the heating container such as, for example, water or oil, is able to remain in the heating container while the housing structure is removable from the sealable enclosure and the inside of the heating container. This is due to the fact that the sealable enclosure remains inside the heating container during the removal.

The immersion heater 10 may be an AC (alternating current) immersion heater, a DC (direct current) immersion heater, or it may be a dual element (both AC and DC).

The sealable enclosure 14 is preferably locatable in the heating container by means of a flange type or screw boss arrangement with the heating container. In the same way, the housing structure is preferably locatable in the heating container by means of a flange type or screw boss arrangement with the heating container.

It will be understood that once the housing structure 12 and the electrically connectable heating source 16 have been removed from the heating container, they may be replaced. In this way, any contents locatable in the heating container is able to remain in the heating container while the housing structure 12 is removable from the sealable enclosure 14 and the inside of the heating container, as the sealable enclosure remains inside the heating container during the removal.

The use of ceramic PTC chips 18 gives an advantage of being a low wattage source of electric heat for an immersion heater 10. These PTC chips 18 are manufactured from a barium-titanate material plus a few key doping materials to provide the desired resistance/temperature characteristics. When electrical voltage is applied to a PTC chip 18, heat is not generated at a constant rate. Rather, as the PTC chips 18 heat up they reach a designed temperature at which the heat output decreases drastically and prohibits the heater from getting hotter. Thus, PTC chips 18 have a designed temperature limit. The PTC chips 18 are preferably housed in a housing structure 12 that is in the form of an aluminium tube 20, due to the good heat transfer properties of aluminium, and they are then wrapped in a sealable enclosure 14 in the form of a sleeve 22 of material of choice. This material of choice is preferably titanium due to its durability, but the material may also be stainless steel, such as when used in the food industry where stainless steel is required to be used.

The ceramic PTC chips 18 preferably used with immersion heater 10 are designed for a specific power output, namely, 1500W or 2200W, or in the region between 100W to 8000W. As shown in Figures 8 and 9, the PTC chips 18 are wrapped in isolation film 24 to isolate the electricity to the PTC heaters 26, and wires 28 are connected to them to conduct electricity to them. As mentioned above, the electricity may be in alternative current (AC) or direct current (DC). The wires connected to the PTC chips are each also individually surrounded by a protective metal shell 30.

It will be noted that when using the ceramic PTC chips 18, the immersion heater 10 may have a long lifespan, but it may be necessary to replace the immersion heater 10 from time to time, due to certain circumstances. These circumstances may be, for example, when a power surge has occurred that has damaged a PTC chip, or where installers did not connect the wiring correctly and this caused damage to a PTC chip. In the case of the immersion heater being used in a water heating tank, it is a very time- consuming task to replace an immersion heater in such a tank as it takes between one to two hours to drain the water heating tank and replace a damaged immersion heater. An advantage provided by the immersion heater 10 of the current invention is that the tube 20 may be screwed off without letting water out of the tank and then the replacement immersion heater 10 may be slid into the outer sealable enclosure, in the form of sleeve 22 that is located in the tank, without the necessity for draining. The water is prevented from leaking out of the tank by the flange type or screw boss arrangement. The immersion heater 10 of the invention may also be used as a resistive immersion heater for apparatus in other industries such as, for example, fryers, deep fryers, sterilising equipment, or the like. Immersion heater 10 in a deep fryer such as a chip fryer is preferably slightly smaller in size than an immersion heater 10 for use in a water heating tank. In the case of an immersion heater 10 for use in a chip fryer, the heating container is filled with oil not water when in use, for heating chip such as, for example, potato chips. Also in this case, the advantage provided by the use of immersion heater 10 in such a heating container is that it may be removed and replaced in the heating container without the need for draining the oil from the heating container. When using ceramic PTC chips 18 in such a heating container, further advantages are provided in that the PTC chips result in a reduction in the use of electricity and, as they provide regulation of the oil temperature, they also result in the overall extension of the life of the oil used in the heating chamber.

Claims

1 . An immersion heater comprising:

- at least one housing structure;

- the housing structure being locatable inside a sealable enclosure;

- the housing structure being removable from the sealable enclosure and the inside of the heating container while the sealable enclosure is locatable inside the housing structure.

2. An immersion heater as claimed in claim 1 , wherein the electrically connectable heat source includes least one PTC chip.

3. An immersion heater as claimed in claim 2, wherein the PTC chip is connectable to insulated conducting wire.

4. An immersion heater as claimed in any one of claims 1 to 3, wherein the electrically connectable heat source includes a plurality of PTC chips.

5. An immersion heater as claimed in any one of claims 1 to 4, wherein the sealable enclosure has a substantially elongate shape.

6. An immersion heater as claimed in claim 5, wherein the housing structure has a substantially elongate shape.

7. An immersion heater as claimed in claim 6, wherein the heat source is made up of a plurality of PTC chips arranged in at least one substantially elongate structure.

8. An immersion heater as claimed in any one of the preceding claims, wherein the heat source is at least one metallic wire.

9. An immersion heater as claimed in any one of claims 1 to 8, which is an AC (alternating current) immersion heater.

10. An immersion heater as claimed in any one of claims 1 to 8, which is a DC (direct current) immersion heater.

1 1 . An immersion heater as claimed in any one of claims 1 to 8, which is a dual immersion heater.

12. An immersion heater as claimed in any one of the preceding claims, wherein the sealable enclosure is locatable in the heating container by means of a flange type arrangement with the heating container.

13. An immersion heater as claimed in any one of claims 1 to 1 1 , wherein the sealable enclosure is locatable in the heating container by means of a screw boss arrangement with the heating container.

14. An immersion heater as claimed in any one of the preceding claims, wherein the housing structure is locatable in the heating container by means of a flange type arrangement with the heating container.

15. An immersion heater as claimed in any one of claims 1 to 13, wherein the housing structure is locatable in the heating container by means of a screw boss arrangement with the heating container.

16. A method of replacing an immersion heater in a heating container, the method comprising:

- replacing the housing structure inside the sealable enclosure locatable inside the heating container while any contents locatable in the heating container is able to remain in the heating container.

17. A method of replacing an immersion heater in a heating container as claimed in claim 16, wherein the electrically connectable heat source includes least one

PTC chip.

18. A method of replacing an immersion heater in a heating container as claimed in claims 17, wherein the PTC chip is connectable to insulated conducting wire.

19. A method of replacing an immersion heater in a heating container as claimed in any one of claims 16 to 18, wherein the electrically connectable heat source includes a plurality of PTC chips.

20. A method of replacing an immersion heater in a heating container as claimed in any one of claims 16 to 19, wherein the sealable enclosure has a substantially elongate shape.

21 . A method of replacing an immersion heater in a heating container as claimed in claim 20, wherein the housing structure has a substantially elongate shape.

22. A method of replacing an immersion heater in a heating container as claimed in claim 21 , wherein the heat source is made up of a plurality of PTC chips arranged in at least one substantially elongate structure.

23. A method of replacing an immersion heater in a heating container as claimed in any one of claims 16 to 22, wherein the heat source is at least one metallic wire.

24. A method of replacing an immersion heater in a heating container as claimed in any one of claims 16 to 23, wherein the immersion heater is an AC (alternating current) immersion heater.

25. A method of replacing an immersion heater in a heating container as claimed in any one of claims 16 to 23, wherein the immersion heater is a DC (direct current) immersion heater.

26. A method of replacing an immersion heater in a heating container as claimed in any one of claims 16 to 23, wherein the immersion heater is a dual immersion heater.

27. A method of replacing an immersion heater in a heating container as claimed in any one of claims 16 to 26, wherein the sealable enclosure is locatable in the heating container by means of a flange type arrangement with the heating container.

28. A method of replacing an immersion heater in a heating container as claimed in any one of claims 16 to 26, wherein the sealable enclosure is locatable in the heating container by means of a screw boss arrangement with the heating container.

29. A method of replacing an immersion heater in a heating container as claimed in any one of claims 16 to 28, wherein the housing structure is locatable in the heating container by means of a flange type arrangement with the heating container.

30. A method of replacing an immersion heater in a heating container as claimed in any one of claims 16 to 28, wherein the housing structure is locatable in the heating container by means of a screw boss arrangement with the heating container.