WO2020060388A1

WO2020060388A1 - Heating system for heating potable water

Info

Publication number: WO2020060388A1
Application number: PCT/MY2019/050060
Authority: WO
Inventors: Tone Vei Tee; Chet Shen Vincent NG; Weng Hong LAU
Original assignee: Thermo Integra Sdn Bhd
Current assignee: Thermo Integra Sdn Bhd
Priority date: 2018-09-20
Filing date: 2019-09-20
Publication date: 2020-03-26
Anticipated expiration: 2021-03-20
Also published as: GB202103305D0; GB2591380B; GB2591380A; MY194158A

Abstract

The present invention provides a heating system for heating potable water. Accordingly, the heating system (100) includes: (i) a boiler or storage tank (120a) with at least one liquid diffuser (130); and (ii) at least one heating element (140) for hot water production; characterised in that the liquid diffuser (130) comprises: a dome-shaped body (132); a plate (150) covering a base of the body (132) to enclose a hollow space between the body (132) and the plate (150), wherein the plate (150) has a central hole (152) and a plurality of arcuate cut-offs (154) along a circumference of the plate (150), forming a plurality of arcuate openings along intersection between the base of the body (132) and the plate (150). It should be noted that the liquid diffuser (130) of the present invention enables ambient or cold water from the inlet (200) to be uniformly introduced into the tank (120a) in a consistent downstream flow (220) of reduced velocity, such that formation of turbulence or forced convection flow within the tank (120a) can be minimised, and hence preserving smooth, divided layers (240) between the hot and cold water to form a stratified tank (120b).

Description

HEATING SYSTEM FOR HEATING POTABLE WATER

FIELD OF INVENTION

The present invention relates to a heating system for heating potable water, and more particularly to a heating system for heating potable water above 75°C.

BACKGROUND OF INVENTION

Water heating systems of various types, such as boiler tank, water dispenser, hot tap water heater, boiling hot tap and the like, are known in the art. In these water heating systems, hot water at desirable high-temperature will then be channelled to dedicated output for domestic and commercial uses.

Depending on the energy source available and the space to be heated, the most common water heating systems are using electric heating element to generate heat which is then dissipated onto the liquid surrounding the heating element. Typically, the electric resistance heating elements used in connection with water heaters are usually made of metal and ceramic components. For example, the classic construction includes a pair of terminal pins brazed to the ends of a resistance alloy coil, which is then disposed axially through a U-shaped or coil shaped tubular metal sheath. The resistance coil is insulated from the metal sheath by a powdered mineral material, usually magnesium oxide.

While such traditional heating elements have been the mainstay for the water heater industry for decades, there have been a number of widely-recognized deficiencies. For example, galvanic currents occurring between the metal sheath and any exposed metal surfaces in the tank may create corrosion of the various anodic metal components of the system. The metal sheath of the heating element, which is typically copper, copper alloy, stainless-steel material or nickel/stainless steel alloy may tend to oxidize after long exposure to corrosion and can break down over time due to the continuously heat up and cool down. Moreover, the metal sheath of the heating element may also tend to encounter limescale problem since it attracts lime deposits from hard water, which can lead to premature failure of the heating element.

In addition to that, most of the conventional water heating systems, including those provided with a storage tank, are usually configured in a manner such that cold water will be fed to lower end of the tank to replace hot water withdrawn from the upper end. When hot water is drawn out from the tank, cold water would need to be fed into the tank to be heated up to replenish drawn out hot water. At times of high consumption, a higher volume of cold water needs to be fed into the tank. Concomitantly, the velocity of cold water flowing into the bottom end of the tank would be higher. Although cold water is supposed to stratify below hot water, the high velocity of cold water gushing into the tank may cause turbulence and creates forced convection flow of cold water from lower part of the tank into hot water band at upper part of the tank. The consequent is that the stratification between hot and cold water in the tank is disturbed and hot water dispensed out from the tank may not be at a desired constant temperature. To overcome this problem, various designs of liquid diffuser have been devised to ameliorate disturbance on stratification between hot and cold water caused by cold water gushing into the tank at high velocity. However, those various designs of liquid diffuser of prior art are unsatisfactory, especially at times of high consumption where cold water is fed into the tank at much faster rate and hence at much higher velocity to replenish rapidly drawn out hot water.

Moreover, none of conventional potable water heating tank has considered the stratification control at temperatures above 75°C, particularly the thermal stratification of the tank, where thermocline layer should be kept as narrow as possible to ensure hot water dispensed out from the tank is at a constant desired temperature.

It is an objective of the present invention is to provide an improved heating element that is anti-scale or will cause scale deposited on the heating element to flake off on its own without external intervention. It is also an objective to provide an improved heating element that is made of corrosion-resistant materials. It is also an objective of the present invention to provide a liquid diffuser with a suitable configuration such that cold water fed into the diffuser will minimise turbulence with the liquid diffuser. Such turbulence may cause water exiting the diffuser through the plurality of openings to be different and may hence induce turbulence in the tank. The improved liquid diffuser allows water to exit there from into the tank in a downwardly direction at the lower end of the tank and at much reduced velocity so that the stratification between hot and cold water in the tank would not be disturbed.

Accordingly, the present invention aims to provide an improved heating system, and more particularly to a heating system for heating potable water that is adapted to overcome the aforementioned limitations and drawbacks. The heating system for heating potable water of the present invention and its combination of features thereof will be described and exemplified in the detailed description.

SUMMARY OF THE INVENTION

The present invention provides a heating system for heating potable water. Accordingly, the heating system includes: (i) a boiler or storage tank with at least one liquid diffuser; and (ii) at least one heating element for hot water production; characterised in that the liquid diffuser comprises: a dome-shaped body; a plate covering a base of the body to enclose a hollow space between the body and the plate, wherein the plate has a central hole and a plurality of arcuate cut-offs along a circumference of the plate, forming a plurality of arcuate openings along intersection between the base of the body and the plate. It should be noted that the liquid diffuser of the present invention enables ambient or cold water from the inlet to be uniformly introduced into the tank in a consistent downstream flow of reduced velocity, such that formation of turbulence or forced convection flow within the tank can be minimised, and hence preserving smooth, divided layers between the hot and cold water to form a stratified tank. In the first instance, turbulence that may be caused by cold water being fed into the diffuser at high velocity is addressed by the dome-shaped configuration of the diffuser. In the second instance, through the designed configuration of the liquid diffuser, the volume of water exiting the diffuser into the tank through each of the plurality of openings is substantially the same and at substantially the same velocity. Consequently, there will be reduction of turbulence created in the tank by water exiting the diffuser into the tank.

Preferably, but not limited to, the heating element is made of corrosion-resistant and anti-scale materials, particularly titanium or titanium alloy. Although the heating element of the heating system of the present invention is preferably made of titanium or titanium alloy, other corrosion-resistant materials of same group in the periodic table that is able to provide similar mechanical and chemical properties to obtain desired optimal operating characteristics may also be contemplated. As such, the heating element made of titanium or titanium alloy should not be construed as limiting in any way. The present invention consists of several novel features and a combination of parts hereinafter fully described and illustrated in the accompanying description and drawings, it being understood that various changes in the details may be made without departing from the scope of the invention or sacrificing any of the advantages of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

It will be understood that several of the drawings are merely schematic representations of the present disclosure. As such, some of the components may have been distorted from their actual scale for pictorial clarity.

The present invention will be fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, wherein:

FIG. 1 is a transparent perspective view of a heating system for heating potable water in accordance with preferred exemplary of the present invention.

FIG. 2 shows different layers of ambient and hot water formation in a stratified tank of the heating system according to preferred exemplary of the present invention.

FIG. 3 shows the dome-shaped body of the liquid diffuser. FIG. 4 shows the bottom plate of the liquid diffuser.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to a heating system, and more particularly to a heating system for heating potable water. Hereinafter, this specification will describe the present invention according to the preferred exemplary of the present invention. However, it is to be understood that limiting the description to the preferred exemplary of the invention is merely to facilitate discussion of the present invention and it is envisioned that those skilled in the art may devise various modifications and equivalents without departing from the scope of the appended claims.

The word“exemplary” is used herein to mean serving as an example, instance, or illustration. Any embodiment described herein as“exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. Likewise, the term“embodiment” of a system, apparatus, device or article of manufacture does not require that all embodiments of the invention include the described components, structure, features, functionality, processes, advantages, benefits, or modes of operation.

The detailed description set forth below in connection with the appended drawings is intended as a description of various exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced. The detailed description includes specific details for the purpose of providing a methodical understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without these specific details. Acronyms and other descriptive terminology may be used merely for convenience and clarity and are not intended to limit the scope of the invention.

For the purpose of present invention, the terms,“cold water” and“ambient water” may refer to the same interpretation and may be used interchangeably. Besides, as used herein the terms,“boiler or storage tank”, may be interchangeably used with various terms such as“boiler tank”,“storage tank”,“stratified tank” or“tank”. The present invention aims to provides an improved heating system for heating potable water which is simple and effective in maintaining a well-defined stratification of hot and cold water and where the thermocline between hot and cold water is thin and distinct. The improved heating system is adapted to operate with a high degree of operating reliability and to have excellent corrosion resistance for durability. The improved heating system for heating potable water also facilitates prolonged periods of service life, lending in both to economy and simplicity of manufacture, and yet be able to substantially reduce in maintenance cost and higher convenience of use.

In particular, the present invention aims to overcome the aforementioned limitations and drawbacks, i.e. the corrosion or durability issues and the convection currents or inconsistent flows in the tank, by providing an improved heating element together with the implementation of liquid diffuser such that to achieve the formation of a stratified boiler tank in the heating system.

The improved heating system for heating potable water according to the preferred mode of carrying out the present invention will now be described in accordance to the accompanying drawings FIGS. 1 to 4, either individually or in any combination thereof.

Referring to FIG. 1 , the heating system (100) for heating potable water generally includes a boiler or storage tank (120a) with at least one liquid diffuser (130), and at least one heating element (140). Accordingly, the boiler or storage tank (120a) generally includes a closed system reservoir with an ambient or cold water inlet (200) and a hot water outlet (300).

By way of example but not limitation, the at least one liquid diffuser (130) is preferably, but not limited to a dome-like shape. It should be noted that the dome like shape liquid diffuser (130) although an exemplary, will be used herein in describing the configurations and functions of the present invention. Flowever other variations, approaches or configuration of the at least one liquid diffuser (130) may be altered in a manner so as to obtain desired optimal operating characteristics. As such, the at least one liquid diffuser (130) of dome-like shape should not be construed as limiting in any way.

It is desirable that water dispensed out of the tank (120a) be maintained at a desired constant temperature. In a water heating system with the tank (120a), when hot water has been drawn out from the tank (120a), cold water or ambient water need to be fed into the tank (120a) to replace the volume of hot water dispensed out. Cold water fed into the tank (120a) is then heated up to replenish the volume of hot water available to be dispensed out. It is important that in the course of feeding ambient water into the tank (120a) that the stratification between hot and cold water in the tank (120a) is not disturbed. Otherwise, the hot water dispensed out from the tank (120a) will not be at a predetermined constant temperature.

Usage of hot water may vary from time to time. During those high consumption hours, the depletion rate of hot water is high and concomitantly, more cold water need to be fed into the tank (120a). Generally, the faster the feed in rate, the more likely that turbulence may result within the tank (120a). Ideally, the thermocline between hot and cold water should be thin and distinct notwithstanding whatever the feed in rate may be.

If a tank (120a) is not provided with the liquid diffuser (130), the high velocity of inrushing cold water may create turbulence or create a forced convection flow within the tank (120a), resulting in cold water being forced upward, against temperature gradient, into hot water located at the upper end of the tank (120a). This would broaden the thermocline band and at worst, could cause the stratification between hot and cold water to vanish completely. In order to maintain a well-defined stratification between hot and cold water, the liquid diffusers (130) are used to minimise or contain turbulences or forced convection flow that may occur when cold water is fed into the tank (120a). For obvious reason, the liquid diffuser is preferably located at lower end of the tank (120a) as cold water on its own would not rise against temperature gradient and mix with hot water at the upper end of the tank (120a). The heater for heating cold water is obviously also located at the lower end of the tank (120a).

Different designs of the liquid diffusers (130) are known in the art. The liquid diffuser (130) of this invention contains several novel features that singularly or in combination, help to abate turbulence caused by feed-in ambient water.

In the preferred embodiment of the present invention as shown in FIG. 3 & FIG. 4, the liquid diffuser (130) is presented as having a dome-shaped body (132) with an opened base and a plate (150) covering the base of the body (132) to enclose a hollow space between the body (132) and the plate (150). By way of example but not limitation, the plate (150) is securely attached to the dome-shaped body (132) by welding, brazing, soldering or any other appropriate attaching method. In the present invention, the plate (150) is round shaped. Flowever, the plate (150) can be designed as elliptical, polygonal or any other shape adapted to match the base of the dome-shaped body (132). Preferably, the plate (150) comprises a central hole (152) and a plurality of spaced apart arcuate cut-offs (154) along a circumference of the plate (150). In the present invention, the central hole (152) serves as an entrance point to feed incoming water into the tank (120a) via the liquid diffuser (130). The plurality of arcuate cut-offs (154) forms the plurality of arcuate openings (156) along intersection between the base of the body (132) and the plate (150). Each of the arcuate cut-offs (154) and each of the arcuate openings (156) is preferably of the same size and of equal distance from the central hole (152). It is possible to have different variations of the openings on the plate (150) to ensure streamlined flow of water into the water tank (120a). For instance, the spaced apart arcuate openings (156) could be located along the loci of a radius that is smaller than the radius of the plate (150) instead of at the circumference edge.

In operation, incoming cold water enters into the space between the body (132) and the plate (150) of the liquid diffuser (130) through the central hole (152). The connection between external source of water and the liquid diffuser (130) may be in the form of a tube or pipe protruding through the central hole (152) with the pipe or tube connected to an external source of water supply, like city water via an ambient or cold water inlet (200) on the tank (120a). Cold water entering into the liquid diffuser (130) will be guided and directed by the inner surface of the dome shaped body (132) from the apex of the dome downwards and towards the plate (150). The streamlined cold water will then exit slowly and smoothly into the tank (120a) through the arcuate openings (156) on the plate (150). The dome-shaped body (132) helps streamline the downward flow of liquid entering into the liquid diffuser (130) to minimise turbulence within the liquid diffuser (130). This streamlined flow, together with the fact that the spaced apart arcuate openings (156) are equidistance from the central hole (152), will ensure that the amount of water exiting each of the arcuate openings (156) is more or less balanced and equal. The combined area of the arcuate openings (156) is bigger than cross- sectional area of the inlet (200). The water exiting the arcuate openings (156) into the tank (120a) has much slower velocity than the cold water through the inlet (200). In this way, the water exiting from the liquid diffuser (130) into the tank (120a) will reduce turbulence in the tank (120a) and hence would ensure good stratification between hot and cold water. This will also ensure that the thermocline band would be narrow and well defined.

As mentioned earlier, the liquid diffuser (130) is preferably located at lower end of the tank. When ambient or cold water is fed from inlet (200) into the liquid diffuser (130) and thence into the tank (120a), the cold water exiting into the tank (120a) will stay at the lower end of the tank. As hot water is on top of the cold water, there could not be convection flow that could disturb the stratification between hot and cold water. Thus, turbulent flow or forced convection flow that may cause thinning of thermocline band in the tank can be minimised with liquid diffuser (130) of the present invention. By minimizing the turbulent flow or forced convection flow, smooth levels dividing layers between the hot water and the incoming ambient or cold water is continued, hence defining a stratified tank (120b) of the heating system (100) for heating potable water (see FIG. 2). As such, more hot water can be delivered or withdrawn from the tank. Hence, the liquid diffuser (130) of the present invention serves to allow ambient or cold water from the inlet (200) to be uniformly introduced into the tank (120a) in a consistent downstream flow (220) of reduced velocity, such that formation of turbulence or forced convection flow within the tank (120a) can be minimised, and hence preserving smooth, divided layers (240) between the hot and cold water to form a stratified tank (120b) as shown in FIG. 2. It will be appreciated that the stratified tank (120b) is able to provide greater proportion of capacity of useful hot water to be continuously delivered at the outlet (300) of the system.

In some countries, potable water supplied to homes and industries from reticulation networks are hard water. Hard water causes a white film that can be seen deposited onto the tank and water heater. Lime scale build-up reduces the efficiency and shortens lifespan of a heater. Such build-up should be prevented or scaled off periodically. Therefore, heating element when used in countries with hard water should be able to withstand greater chemical punishment. In addition, the heater should preferably be made of anti-scale materials.

In the preferred exemplary of the present invention, the heating element (140) is preferably made of titanium or titanium alloy. Further, a heating element (140) made of titanium or titanium alloy is able to withstand greater chemical punishment, without the pitting, etching or surface breakdown. It is noted that scale built-up on heater made of titanium or titanium alloy tends to flake off on its own without intervention. This is because titanium or titanium alloy is adapted to produce a dioxide film that continually migrates to its surface and is able to detach harmful content depositing onto or enveloping the surface therefrom. Titanium or titanium alloy is relatively inert and thus has no or little risk of leaching, making water heating using heater made of titanium or titanium alloy safe and hygienic for human consumption.

The heating element (140) of the heating system of the present invention is preferably made of titanium or titanium alloy and although an exemplary, heating element (140) made of this material will be used herein in describing the functions of the present invention. However other corrosion-resistant and anti-scale materials of same group in the periodic table that is able to provide similar mechanical and chemical properties to obtain desired optimal operating characteristics may also be contemplated. As such, the heating element (140) made of titanium or titanium alloy should not be construed as limiting in any way.

It should be noted that the configurations and arrangements of various machines or elements used to carry out the above-mentioned system are illustrative and exemplary only and are not restrictive of the invention. One of ordinary skill in the art would recognize that those configurations, arrangements and variations used herein may be altered in a manner so as to obtain different optimal effects or desired operating characteristics. As such, the above-described should not be construed as limiting in any way, but as a best mode contemplated by the inventor for carrying out the invention.

It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases“at least one” or“one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles“a” or“an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases“one or more” or“at least one” and indefinite articles such as “a” or“an” (e.g.,“a” and/or“an” should typically be interpreted to mean“at least one” or“one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of“two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the principle and scope of the invention, and all such modifications as would obvious to one skilled in the art intended to be included within the scope of following claims.

Claims

1 . A heating system for maintaining stratified potable water to a temperature above 75°C, the heating system (100) includes: (i) a boiler or storage tank (120a) with at least one liquid diffuser (130); and

(ii) at least one heating element (140) for hot water production; characterised in that the liquid diffuser (130) comprises:

a dome-shaped body (132);

a plate (150) covering a base of the body (132) to enclose a hollow space between the body (132) and the plate (150),

wherein the plate (150) has a central hole (152) and a plurality of arcuate cut-offs (154) along a circumference of the plate (150), forming a plurality of arcuate openings (156) along intersection between the base of the body (132) and the plate (150).

2. The heating system as claimed in Claim 1 , wherein the heating element (140) is made of corrosion-resistant and anti-scale materials, particularly titanium or titanium alloy.