GB2622273A

GB2622273A - Water heater

Info

Publication number: GB2622273A
Application number: GB2213282.3A
Authority: GB
Inventors: Patrick Conway Sean; James Baxter Neil
Original assignee: Kohler Mira Ltd
Current assignee: Kohler Mira Ltd
Priority date: 2022-09-12
Filing date: 2022-09-12
Publication date: 2024-03-13
Anticipated expiration: 2042-09-12
Also published as: IE20230231A2; GB2622273B; GB202213282D0

Abstract

An instantaneous water heater 1 comprising: a heater tank 2 with an inlet 16 and outlet 14 and a heating element 28a, 28b extending along a fluid flow path through the heater tank, wherein baffles 33 are disposed in the tank to direct fluid towards the element to improve heat transfer. The tank may comprise an open end 5 with a cap 6 secured thereon and the baffles may be received into the tank by an insert. The inlet may extend as a tube 20 through the wall of the tank, opening to an internal volume 9 of the tank and the baffles may be disposed adjacent this inlet tube. The baffles may also be integrally formed on the tank side wall.

Description

WATER HEATER

This disclosure relates to water heaters and more specifically relates to instantaneous water heaters such as electric showers. The disclosure also relates to plumbing systems, e.g. ablutionary systems, comprising such water heaters.

Instantaneous water heaters typically comprise a tank. Water, typically cold water, is supplied to the tank from a water supply. The water in the tank is heated and is then conveyed from the tank to a fluid delivery device, e.g. a shower head when the instantaneous water heater is part of an electric shower system.

One or more heating elements may be disposed within the tank. The heating clement(s) is/arc operable to heat water in the tank by the transfer of thermal energy from the heating element(s) to the water as the water is in the tank, e.g. as the water passes through the tank. Over time, limescale may build up on the heating element(s), leading to reduced water heating performance. This problem may be particularly severe in hard water areas. Also, the problem typically may be greater for heating elements that operate at higher heating element temperatures.

"Hot shot" is a condition that can occur when an instantaneous water heater, in particular an electric shower, is restarted shortly after being stopped abruptly from a steady running state. The retained thermal energy stored in the mass of the heating elements will dissipate into the retained water within the tank causing a significant increase in the stored water temperature. Typically, this may be around 20°C to 30°C higher than the tank running temperature. A user restarting the instantaneous water heater, e.g. the electric shower, may experience a "hot shot", i.e. a burst of hotter water, which may be uncomfortable and/or dangerous A first aspect provides an instantaneous water heater comprising: a heater tank having a heater tank inlet and a heater tank outlet, the heater tank further comprising: a heating element arranged to extend along at least a portion of a fluid flow path through the heater tank, the fluid flow path extending from the heater tank inlet to the heater tank outlet; and one or more baffles, disposed within the heater tank along the fluid flow path, configured to direct fluid towards the heating clement for the purpose of improving heat transfer.

As a result of the baffle(s) directing fluid, in use, towards the heating element for the purpose of improving heat transfer, the peak heating clement temperature may be reduced whilst delivering the same water temperature to the heater tank outlet. Additionally or alternatively, the average (mean) heating element temperature may be reduced whilst delivering the same water temperature to the heater tank outlet. Consequently, limescale production may be reduced. Additionally, the possible occurrence of "hot shot" may be reduced and/or the severity (e.g. temperature and/or duration) of any "hot shot" that occurs in use may be reduced The heater tank may define an internal volume.

The heater tank may comprise a first end wall and a second end wall with one or more side walls connecting the first end wall to the second end wall. The first end wall and/or the second end wall may be formed integrally with one or more of the side walls. The first end wall and/or the second end wall may be connected to one or more of the side walls by any suitable means such as pins, clips, a clamp or any suitable chemical and/or mechanical bonding, for example.

The first end wall may be a base.

The second end wall may be a cap.

In an implementation, the heater tank may comprise a heater tank vessel having an open end and the or a cap secured to the heater tank vessel. Together the heater tank vessel and the cap may enclose the internal volume of the heater tank. The heater tank vessel may comprise the or a base and one or more side walls extending from the base to the open end.

The heater tank inlet may be disposed at any suitable location on or within the heater tank. The heater tank inlet may be disposed at or near the first end wall. The heater tank inlet may be disposed at or near the second end wall.

In an implementation, an inlet tube may extend through a wall of the heater tank, e.g, the first end wall, the second end wall or one of the side walls. The inlet tube may have a first end located outboard of the heater tank and a second end opening into the internal volume. The second end of the inlet tube may be considered the heater tank inlet. Thc first end of the inlet tube may be adapted to be connected, in use, to a fluid supply pipe, e.g. a water supply pipe.

In an implementation, the inlet tube may pass through the base and extend towards the open end of the heater tank vessel. The second end of the inlet tube may be located a short distance from the cap.

The inlet tube may be located substantially centrally within the heater tank.

For nstance, the inlet tube may be integrally formed with the heater tank vessel.

The heater tank outlet may bc disposed at any suitable location on or within the heater tank. The heater tank outlet may be disposed at or near the first end wall. The heater tank outlet may be disposed at or near the second end wall.

The heater tank inlet and the heater tank outlet may be disposed at or near opposing ends of the heater tank, e.g. the heater tank outlet may be disposed at or near the first end wall and the heater tank inlet may be disposed at or near the second end wall or vice versa. The heater tank inlet and the heater tank outlet may be disposed at or near the same end of the heater tank.

The heater tank inlet and the heater tank outlet may each be configured to form a connection with a separate conduit, pipe, or the like, suitable for conveying a flow of fluid. For example, the heater tank inlet may be configured to form a connection with a pipe configured to convey a flow of fluid from a plumbing supply. For example, the heater tank outlet may be configured to form a connection with a hose configured to convey a flow of fluid to a fluid delivery device such as a shower spray head The fluid flow path may extend from the second end of the inlet tube to the heater tank outlet. The fluid flow path may extend along a substantial portion of a height of the heater tank. The fluid flow path may be described as being parallel with a longitudinal axis extending through the heater tank from the first end wall to the second end wall.

The inlet tube may be disposed substantially centrally within the heater tank. In this way, edges of the fluid flow path may be defined by an outer wall of the inlet tube and one or more inner surfaces of the side wall(s) of the heater tank.

The heating element may be an electrical heating element.

The heating element may extend along a substantial portion of the fluid flow path.

The heating element may comprise a helical portion. The helical portion may extend in a direction between the first end wall and the second end wall of the heater tank. In an implementation, the helical portion of the heating element may be outboard of the or a inlet tube. The helical portion of the heating element may encircle the or a inlet tube.

The instantaneous water heater may comprise more than one heating element. Each heating element may be arranged to extend along at least a portion of the fluid flow path through the heater tank.

In an implementation, each heating element may comprise a helical portion extending in a direction between the first end wall and the second end wall of the heater tank.

For example, the instantaneous water heater may comprise two heating elements, each heating element having a helical portion The helical portions may be arranged in a double helix. The double helix may be arranged around the inlet tube One or more baffles may be disposed adjacent an inner surface of a side wall of the heater tank. The one or more baffles may be arranged to extend from the inner surface of the side wall into the fluid flow path. in this way, the one or more baffles may extend from the inner surface of the side wall and towards the heating element(s). The one or more baffles may comprise a surface angled relative to the longitudinal axis extending through the heater tank from the first end wall to the second end wall. The one or more baffles may comprise a surface disposed substantially perpendicular to the longitudinal axis extending through the heater tank from the first end wall to the second end wall.

One or more of the baffles may extend up to 5% of a distance from the inner surface of the side wall to the inlet tube, or up to 10%, up to 20%, up to 30%, up to 40% or up to 50% of the distance from the inner surface of the side wall to the inlet tube.

One or more of the baffles may divert fluid flowing near or along the side wall(s) of the heater tank. The diverted fluid may be diverted towards one or more of the heating elements.

The one or more baffles may comprise any suitable shape such as, for example, a planar member.

One or more of the baffles may extend around any suitable portion of an inner perimeter defined by the side wall(s) of the heater tank. For example, at least one of the baffles may extend around up to or at least 25%, up to or at least 50%, up to or at IS least 75% or up to 100% of the inner perimeter defined by the side wall(s) of the heater tank. For instance, at least one of the baffles may extend around approximately 25%, 50%, 75% or 100% of the inner perimeter defined by the side wall(s) of the heater tank.

One or more baffles may be disposed adjacent the inlet tube. The one or more baffles may be arranged to extend from an outer surface of the inlet tube and into the fluid flow path. In this way, the one or more baffles may extend from the outer surface of the inlet tube and towards the heating element(s). The one or more baffles may comprise a surface angled relative to the longitudinal axis extending through the heater tank from the first end wall to the second end wall. The one or more baffles may comprise a surface disposed substantially perpendicular to the longitudinal axis extending through the heater tank from the first end wall to the second end wall.

One or more of the baffles may divert fluid flowing along or near to the outer surface of the inlet tube. The diverted fluid may be diverted away from the outer surface of the inlet tube and towards the heating element(s).

The one or more baffles adjacent the inlet tube may comprise any suitable shape such as, for example, a planar member.

One or more of the baffles adjacent the inlet tube may extend at least partially along a helical path extending in a lengthwise direction along the inlet tube, Each baffle adjacent the inlet tube may comprise any suitable length. One or more of the baffles may extend around any suitable portion of an outer perimeter, e.g. circumference, of the inlet tube. For example, at least one of the baffles may extend around up to or at least 25%, up to or at least 50%, up to or at least 75% or up to 100% of the outer perimeter of the inlet tube.

The instantaneous water heater may comprise any number of baffles, e.g. a plurality of baffles. The instantaneous water heater may comprise up to or at least five baffles, up to or at least 10 baffles, up to or at least 20 baffles or up to or at least 50 baffles.

Each baffle may comprise a similar length. Each baffle may be offset from at least I5 one adjacent baffle.

Each baffle may be evenly spaced apart from adjacent baffles, e.g. in the direction of the longitudinal axis extending through the heater tank from the first end wall to the second end wall One or more of the baffles may be formed integrally with the heater tank or a part thereof. For instance, one or more of the baffles may be formed integrally with the side wall(s) of the heater tank, the heater tank vessel and/or the inlet tube. One or more of the baffles may be provided by a baffle insert configured to be received in the heater tank. The or each baffle insert may comprise a frame with one or more baffles attached thereto.

By providing the baffle(s) on one or more baffle inserts, the baffle(s) may be retrofitted into an existing heater tank, in order to improve performance of the existing heater tank.

A second aspect provides a plumbing system comprising an instantaneous water heater of the first aspect and at least one fluid delivery device in fluid communication with the heater tank outlet.

The fluid may be water.

The heater tank inlet may be in fluid communication with a fluid supply, e.g. a water supply.

The instantaneous water heater may be operable to deliver fluid, e.gwater to the fluid delivery device(s) at a user-selected temperature and/or flow rate.

The plumbing system may be an ablutionary system, e.g. an electric shower system.

The electric shower system may comprise an electric shower unit mounted on a wall. The electric shower unit may comprise a casing housing the instantaneous water heater. The instantaneous water heater may be connected to a water supply point such as a plumbing supply. A hose may provide fluid communication from the instantaneous water heater to a spray head located downstream thereof. A shower tray or bath tub may be present to collect the water emitted from the spray head.

Except where mutually exclusive, any of the features of any of the above-described aspects may be employed mutat s mutandis in any of the other above-described 20 aspects Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings: Figure 1 shows a sectional view of an instantaneous water heater; Figure 2 shows an exploded view of the instantaneous water heater of Figure 1; Figure 3 shows a computational fluid dynamics heat map representation of the heating elements disposed within an instantaneous water heater not according to the claimed invention; Figure 4 shows a computational fluid dynamics heat map representation of the heating elements disposed within the instantaneous water heater of Figures 1 and 2; and Figure 5 shows schematically an electric shower system.

Figure 1 shows a sectional view of an instantaneous water heater 1. Figure 2 shows an exploded view of the instantaneous water heater 1.

The instantaneous water heater I comprises a heater tank 2. The heater tank 2 is formed by a heater tank vessel 3 having an open end 5 and a cap 6 secured to the heater tank vessel 3. The cap 6 covers the open end 5 of the heater tank vessel 3. Together the heater tank vessel 3 and the cap 6 enclose an internal volume 9 of the heater tank 2 The heater tank vessel 3 has a base 4 and one or more side walls 8 extending from the base 4 to the open end 5 of the heater tank vessel 3.

An inlet tube 20 passes through the base 4 and extends towards the open end 5 of the heater tank vessel 3. The inlet tube 20 has a first end 16 located outboard of the base 4 and a second end 12 located a short distance from the cap 6 and opening into the internal volume 9. The first end 16 of the inlet tube 20 is adapted to be connected, in use, to a water supply pipe (not shown). I5

An outlet 14 leading from the internal volume 9 of the heater tank 2 extends through one of the side walls 8 at a location close to the base 4. The outlet 14 is adapted to be connected to a hose for conveying water to a shower head (not shown) downstream of the heater tank 2.

A fluid flow path extends through the heater tank 2 from the second end 12 of the inlet tube 20 to the outlet 14.

A two-part clamping ring 7 secures the cap 6 to the heater tank vessel 3. A scaling element 18 clamped between an outer surface of the heater tank vessel 3 and an inner surface of the cap 6 provides a fluid-tight seal The instantaneous water heater 1 comprises a first electrical heating element 28a and a second electrical heating element 28b. Each of the first electrical heating element 28a and the second electrical heating clement 28b includes a helical portion 29a, 29b. The helical portions 29a, 29b are arranged in a double helix arranged around the inlet tube 20. The first electrical heating element 28a passes through the cap 6 and includes a first end 30a and a second end 30b. Each of the first end 30a and the second end 30b of the first electrical heating element 28a is located outboard of the cap 6. Each of the first end 30a and the second end 30b of the first electrical heating element 28a is adapted to be connected to a power supply (not shown). The second electric& heating clement 28b passes through the cap 6 and includes a first end 31a and a second end 31b. Each of the first end 31a and the second end 31b of the second electrical heating element 28b is located outboard of the cap 6. Each of the first end 31a and the second end 3 lb of the second electrical heating element 28b is adapted to be connected to a power supply (not shown).

A first baffle insert 32 comprises a first frame 35 configured to be received in the heater tank vessel 3. The first frame 35 includes a first set of baffles 33. The first frame 35 is configured such that each one of the first set of baffles 33 abuts an inner surface of one of the side walls 8. When the first baffle insert 32 is in place within the heater tank vessel 3, each one of the first set of baffles 33 protrudes from the inner surface of one of the side walls 8 The first frame 35 comprises a first elongate support member 34a and a second elongate support member 34b. The first elongate support member 34a and the second elongate support member 34b are parallel to each other. The first elongate support member 34a and the second elongate support member 34b both extend in a substantially vertical direction. The first elongate support member 34a and the second elongate support member 34b are arranged such that they are adjacent opposing inner surfaces of the side walls 8 of the heater tank vessel 3 when the first baffle insert 32 is in place in the heater tank vessel 3. Each one of the first set of baffles 33 extends from the first elongate support member 34a to the second elongate support member 34b. Each one of the first set of baffles 33 is bowed in such a way that it substantially conforms along its length to the shape of the inner surface of the side walls 8 of the heater tank vessel 3. In the illustrated example, the first set of baffles 33 comprises seven baffles 33. The baffles 33 are regularly spaced along the first elongate support member 34a and the second elongate support member 34b. Four baffles 33 are bowed in a first direction and three baffles 33 arc bowed in a second direction opposite to the first direction. The four baffles 33 bowed in the first direction and the three baffles 33 bowed in the second direction are interposed with each other.

A second baffle insert 36 comprises a second frame 37 configured to be received in the heater tank vessel 3. The second frame 37 includes a second set of baffles 39.

The second frame 37 is configured such that each one of the second set of baffles 39 is adjacent an outer surface 26 of the inlet tube 20. Each one of the second set of baffles 39 extends away from the outer surface 26 of the inlet tube 20.

The second frame 37 has the form of a tubular sleeve 38 shaped and dimensioned to fit snugly around the inlet tube 20. The baffles of the second set of baffles 39 form a broken helical pattern protruding from an outer surface 40 of the tubular sleeve 38.

The first set of baffles 33 are disposed outboard of the helical portions 29a, 29b of the first electrical heating element 28a and the second electrical heating element 28b. The second set of baffles 39 are disposed inboard of the helical portions 29a, 29b of the first electrical heating element 28a and the second electrical heating element 28b.

In use, cold water enters the internal volume of the heater tank from the second end 12 of the inlet tube 20. The water then flows in a generally downward direction towards the outlet 14. When the instantaneous water heater 1 is installed as part of an electric shower system, the water leaving the outlet 14 has a user-selected temperature. The first electrical heating element 28a and the second electrical heating clement 28b operate to heat the water in the heater tank 2 as it flows along the flow path from the second end 12 of the inlet tube 20 to the outlet 14. The temperature of the water increases as it flows along the flow path from the second end 12 of the inlet tube 20 to the outlet 14. The temperature of the helical portions 29a, 29b of the first electrical heating element 28a and the second electrical heating element 28b generally decreases with distance along the flow path from the second end 12 of the inlet tube 20 to the outlet 14. Thus, it will be appreciated that the first electrical heating element 28a and the second electrical heating element 28b are arranged such that the hottest section of their respective helical portions 29a. 29b heats the coldest water flowing along the flow path and vice versa.

Each one of the first set of baffles 33 is configured to divert water flowing, in use, along or close to the inner surface of one or more of the side walls 8 of the heater tank vessel 3 away from the side wall(s) 8 and towards the first electrical heating element 28a and the second electrical heating element 28b.

Each one of the second set of baffles 39 is configured to divert water flowing, in use, along or close to the outer surface of the inlet tube 20 away from the inlet tube 20 and towards the first electrical heating element 28a and the second electrical heating clement 28b.

Accordingly, it will be appreciated that the water diverted by the baffles is brought closer to the first electrical heating element 28a and the second electrical heating element 28b than it would be if the baffles were not present.

The first set of baffles may include any number of baffles. For instance, the first set of baffles may include up to or at least five baffles, up to or at least 10 baffles, up to or at least 20 baffles or up to or at least 50 baffles The second set of baffles may include any number of baffles. For instance, the second set of baffles may include up to or at least five baffles, up to or at least 10 baffles, up to or at least 20 baffles or up to or at least 50 baffles. I5

Each one of the baffles may have any suitable size and shape for carrying out their function.

Any suitable arrangement and number of electrical heating elements may be employed. For instance, the instantaneous water tank may comprise one or more electrical heating elements arranged to extend along at least a portion of the or a fluid flow path through the heater tank.

There may be any number and arrangement of fluid flow paths through the heater tank.

Figures 3 and 4 illustrate computational fluid dynamics (CFD) heat map representations of the temperature of the first heating element 28a and the second heating element 28b operating to deliver water to the outlet [Ref] at a temperature of X°C and a flow rate of Y Umin with an inlet water temperature of Z°C. Figure 3 illustrates the situation for the heater tank l' without the first set of baffles and the second set of baffles therein Figure 4 illustrates the comparable situation for the heater tank l' with the first set of baffles and the second set of baffles therein. Comparing Figures 3 and 4 therefore provides an indication of the effect of the presence of the first set of baffles and the second set of baffles.

In Figure 3, the variation in temperature of the first electrical heating dement 28a and the second electrical heating clement 28b arc indicated by the shading. The temperature of the heat elements varies from a lowest temperature of around 37°C to a highest temperature of around 180°C. The highest temperature occurs in parts of the helical portions that are closest to the second end of the inlet tube, i.e. where the water temperature is at its lowest. The lowest temperatures occurs in parts of the helical portions that are closest to the outlet, i.e. where the water temperature is at its highest.

In Figure 4, the variation in temperature of the first electrical heating element 28a and the second electrical heating element 28b are indicated by the shading. The temperature of the heat elements varies from a lowest temperature of around 36°C to a highest temperature of around 140°C. The highest temperature occurs in parts of the helical portions that are closest to the second end of the inlet tube, i.e. where the water temperature is at its lowest. The lowest temperatures occurs in parts of the helical portions that are closest to the outlet, i.e. where the water temperature is at its highest.

Comparing Figures 3 and 4, it is notable that the highest temperate of the heating elements is around 40°C less in Figure 4 than in Figure 3. This represents a decrease of around 22%. The average (mean) temperature of the heating elements in Figure 4 is approximately 15°C less than the average (mean) temperature of the heating elements in Figure 3.

These decreases in the highest temperature of the heating elements and the average temperature of the heating elements may result in a decrease in limescalc build-up during operation of the heater tank 1'. Accordingly, the performance reliability, efficiency and/or service lifetime of the heater tank l' may be improved.

In addition, these decreases in the highest temperature of the heating elements and the average temperature of the heating elements may reduce the severity of any "hot shots" that occur during use.

Figure 5 shows schematically an electric shower system 50. An electric shower unit 51 is mounted on a wall 52. The electric shower unit 51 comprises a casing 55 housing an instantaneous water heater such as the instantaneous water heater 1 described above. The instantaneous water heater is connected to a water supply point (not shown) located within the wall 52. A hose 53 provides fluid communication from the instantaneous water heater to a spray head 54 located downstream thereof. A shower tray or bath tub (not shown) may be present to collect the water emitted from the spray head 54.

By virtue of the baffles diverting the water flow within the heater tank. the water flow within the heater tank may be conditioned so that overall it flows more intimately with (i.e. closer to) the heating element(s). Accordingly, heat transfer from the heating element(s) to the water may be improved. A reasonable volume of water may be retained in the heater tank, so that on cessation of flow, there is still water to dissipate the residual heat energy into.

Various modifications can be made to the example embodiments described herein without departing from the scope of the invention. I5

Except where mutually exclusive, any of the features may be employed separately or in combination with any other features and the disclosure extends to all combinations and sub-combinations of one or more features disclosed herein.

Claims

CLAIMS1 An instantaneous water heater comprising: a heater tank having a heater tank inlet and a heater tank outlet, the heater tank further comprising: a heating element arranged to extend along at least a portion of a fluid flow path through the heater tank, the fluid flow path extending from the heater tank inlet to the heater tank outlet, and one or more baffles, disposed within the heater tank along the fluid flow path, configured to direct fluid towards the heating element for the purpose of improving heat transfer.
2 An instantaneous water heater according to claim 1, wherein the heater tank comprises a first end wall and a second end wall with one or more side walls connecting the first end wall to the second end wall.
IS 3. An instantaneous water heater according to claim I or claim 2, wherein the heater tank comprises a heater tank vessel having an open end and a cap secured to the heater tank vessel.
4. An instantaneous water heater according to claim 1, claim 2 or claim 3, wherein an inlet tube extends through a wall of the heater tank.
An instantaneous water heater according to claim 4, wherein the inlet tube has a first end located outboard of the heater tank and a second end opening into an internal volume of the heater tank.
6. An instantaneous water heater according to claim 5, wherein the fluid flow path extends from the second end of the inlet tube to the heater tank outlet.
7 An instantaneous water heated according to any one of the preceding claims, wherein the heating clement is an electrical heating clement.
8 An instantaneous water heater according to any one of the preceding claims, wherein the heating element extends along a substantial portion of the fluid flow path.
9. An instantaneous water heater according to any one of the preceding claims, wherein the heating element comprises a helical portion.
10. An instantaneous water heater according to any one of the preceding claims, wherein one or more of the baffles are disposed adjacent an inner surface of a side wall of the heater tank.
11. An instantaneous water heater according to claim 4, or any one of claims 5 to 10 when dependent on claim 4, wherein one or more baffles are disposed adjacent the inlet tube 12.
An instantaneous water heater according to any one of the preceding claims comprising up to or at least five baffles, up to or at least 10 baffles, up to or at least 20 baffles or up to or at least 50 baffles. I513.
An instantaneous water heater according to any one of the preceding claims, wherein one or more of the baffles are formed integrally with the heater tank or a part thereof. .
14 An instantaneous water heater according to any one of the preceding claims, wherein one or more of the baffles are provided by a baffle insert configured to be received in the heater tank.
15. A plumbing system comprising an instantaneous water heater according to any one of claims 1 to 14 and at least one fluid delivery device in fluid communication with the heater tank outlet.