GB2249617A

GB2249617A - Storage water heater

Info

Publication number: GB2249617A
Application number: GB9122824A
Authority: GB
Inventors: Kwok Man Edward Chan
Original assignee: GERMAN POOL
Current assignee: GERMAN POOL
Priority date: 1990-10-29
Filing date: 1991-10-28
Publication date: 1992-05-13
Anticipated expiration: 2011-10-28
Also published as: GB9023474D0; HK45494A; GB9122824D0; GB2249617B

Abstract

A water heater comprises a housing 5 which encloses a tank 6 in which water is heated, a cold water inlet pipe 2a, 2b to the tank, and a hot water supply outlet pipe 7 characterised in that the water inlet pipe includes a substantially inverted U-shape portion within the housing the highest point of which is near and preferably above the inner tank. The heater also includes an anti-vacuum valve 1 in the inlet pipe and the outlet pipe 7 has an inlet at or near the top of the tank and an outlet at either the top (Fig 1, not shown) or the bottom (Fig 2) of the tank. <IMAGE>

Description

WATER HEATER This invention relates to an improved water heater, and in particular, although not exclusively, a storage electric hot water heater.

Known types of storage hot water heaters include: (i) Cistern-fed water heaters A water heater supplied from a cistern, in which the flow of water is controlled by one or more valves in the outlet system and so arranged that the expanded water can return to a feed cistern.

(2) Open-outlet water heaters A water heater in which-the flow of water is controlled by a valve in the inlet pipe and so arranged that the expanded water can overflow through the outlet pipe.

(3) Cistern-type water heaters A water heater which has a feed cistern as an integral part of the appliance.

(4) Closed water heaters A water heater designed to work under the pressure of tulle waster supply inairiu, tile flow of water being controlled by one or more valves in the outlet system. These heaters have the disadvantages that special safety devices which require special attention and experience during the process of installation.

Such types of storage hot water heaters require special safety devices andlor extensive piping to be used therewith.

It is an object of the invention to overcome one or more of the disadvantages of these known types of heaters.

In accordance with the invention, a water heater comprises a housing which encloses a tank in which water is heated, a water inlet pipe for supply of relatively cold water to the tank, and a water outlet pipe for supply of relatively hot water from the tank characterised in that t least a portion of the water inlet pipe has a substantially inverted U-shape, wherein the highest point of the inverted U-shaped portion of ttne water inlet pipe is near or above the top of the tank, and wherein the inverted U-shaped portion of the water inlet pipe is substantially within the housing.

This invention overcomes the problem of having to install an independent supply pipe, at the place of installation of the heater and outside of the beater, that branches off from the feed pipe at a point above the top of the water heater, or some other device to prevent the water from draining down from the water heater if there is a failure at the source of water supply.

Suitably the highest point of the inverted U-shaped portion of the water inlet pipe is above the top of the tank.

Preferably an anti-vacuum valve is provided at the highest point of the inverted U-shaped portion of the water inlet pipe. The anti-vacuum valve is provided to prevent heated water from being syphoned back to the supply pipe.

Advantageously the water inlet pipe enters into the housing of the water heater substantially at the base thereof, whilst the exit of the water inlet pipe is substantially at the base of the tank.

Preferably the entrance of the water outlet pipe is substantially at the top of the tank.

Advantageously a pressure and temperature relief valve is provided with the heater for safety purposes.

Suitably the space between the housing and the tank is substantially filled with insulating material to save energy.

Preferably a heating element is provided within the tank, to heat the relatively Cold water entering the tank.

Advantageously the inner tank is always substantially filled up with water, and thus the heating element is always immersed in water In use, the water heater of this invention safely and effectively prevents contamination to water supply system as it accurately prevents water frorn draining down from the water heater if there is a failure at the source of water supply Syphonage of water back to the supply pipe is further eliminated by the anti-vacuum valve incorporated therein.In consequence, the incorporation of an expansion vessel and non-return valve, or a similar device at the inlet of the water heater is eliminated* With a heater in accordance with the invention, the unnecessary expenses of employing a we experlenced pluSWer to install an independent up-stand pipe plus other safety devices is not required. The installation of a pressure type water heater becomes simple, easy and safe The inlet pipe which acts as a combined supply and upstand pipe ensures maximum safety and thermal efficiency for the end user.

This invention therefore provides a complete combined supply and upstand pipe equipped with the necessary safety devices This combined pipe is to be built in within the water heater unit to provide a compact self-contained storage water heater with absolute safety.

Advantages over Conventional Upstand Pipe (1) neat and tidy exterior (2) simple piping work and installation - the water heater unit can be installed in alniost every place with the provision of an inlet and outlet pipe. No other special piping and plumbing work is required, and installation faults can be avoided.

(3) simple maintenance (4) absolute safety for every user as all the necessary safety devices have been built inside the water heater unit with full compliance of Waterworks Regulations (5) saves space as no extra space is required to accommodate any additional piping (6) no contamination to water mains as any draining down of water from the water heater is prevented in case of water supply failure. In addition back syphonage is further prevented by the anti-vacuum valve. Damage to the inner tank due to loss of pressure is further prevented.

As the inner tank is always filled up with water, the inner stainless steel surface of the tank will not be in contact with air, and thus corrosion is minimized.

The invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 shows a cross-sectional side view of a water heater in accordance with the invention; and Figure 2 shows a cross-sectional side view of an alternative water heater in accordance with the invention.

In Figure 1 of the drawings, a vertical floor standing water heater is shown with a vertical water inlet pipe 2a which forms part of an inverted U-snaped combined supply and upstand pipe 2. The inlet pipe 2a enters the side of the housing 5, the side of an inner tank 6, and goes up therefrom through the top of the inner tank 6. The upper portion of the inlet pipe 2a (i,e. the top part of the combined supply and upstand pipe 2) extends through the top part of the housing 5. An anti-vacuum valve 1 is provided screwed in at this end of the pipe Another piece of angled supply piping 2b is branched from the vertical inlet pipe 2a at a point above the top of the inner tank 6.

This complete piece of joined piping runs from the water inlet point 9 to the water outlet point 10 in the inner tank 6, and forms a combined supply and upstand pipe 2.

The inlet pipe 2a is joined at or near the inlet point 9 to main water supply pipes (not shown).

Under normal operation, when water *.s drawn from the inner tank 6, water goes from the water inlet point 9 all the way up to the top of the inverted U-shaped portion of the pipe, and then down the supply pipe 2b again supplying water to the inner tank 6 replacing any draw-off of water through the tank outlet pipe 7 The supply pipe 2b runs down to near the bottom of the inner tank to ensure that cold water is fed to the bottom part of the tank where the heating element is located. The arrangement is such that the inner tank is always substantially filled up with water.

In case of failure at the source of water supply eg. during water shortage period, any drain-off of water from the inner tank 6 through the combined supply and up-stand pipe 2 is prevented. Under such circurnstances the anti-vacuum valve 1 will be activated. Air will be drawn into the inlet pipe 2 creating an air gap in the pipe.

Draw-off of water from the inner tank 6 is therefore prevented at the U-loop incorporated therein at the vertical inlet pipe 2a and the branching-off above the top of the inner tank 6.

The heater is also shown with a pressure and temperature relief valve 3 connected to a pressure and temperature relief valve sensor 11, insulation material 4 around the tank 6, and a heating element 8.

In Figure 2 of the drawings, a similar water heater to that of Figure 1 is shown. The main difference is that the heater of Figure 1 is floor standing, whilst the heater of Figure 2 is a vertical wall mounted model. As a result, the inlet pipe 9 for the water heater of Figure 1 enters the housing at its side, whilst the inlet pipe 9 for the water heater of Figure 2 enters the housing at its base. Furthermore, the outlet pipe 7 for the water heater of Figure 1 exits the housing at.its top, whilst the outlet pipe 7 for the water heater of Figure 2 exits the housing at its base. The entrance for the outlet pipes 7 of both heaters, however, is still positioned in the top region of the inner tank 6.

Figure 2 also shows a drain 12 for the heater, a thermostat 13 connected to a thermostatic sensor 14, and a thermal cut-out 15 connected to a thermal cut-out sensor 16 for operation and control of the heating element

Claims

cLAIMs 1. A water heater comprising a housing which encloses a tank in which water is heated, a water inlet pipe for supply of relatively cold water to the tank, and a water outlet pipe for supply of relatively hot water from the tank characterised in that at least a portion of the water inlet pipe has a substantially inverted U-shape, wherein the highest point of the inverted U-shaped portion of the water inlet pipe is near or above the top of the inner tank, and wherein the inverted U-shaped portion of the water inlet pipe is substantially within the housing,
2. A water heater as claimed in Claim 1 wherein the highest point of the inverted U-shaped portion of the water inlet pipe is above the top of the tank.
3. A water heater as claimed in either Claim 1 or 2 wherein an anti-vacuinn valve is provided at the highest point of the inverted U-shaped portion of the water inlet pipe.
4. A water heater as claimed in any preceding claim wherein the water inlet pipe enters into the housing of the water heater substantially at the base thereof.
5. A water heater as claimed in any preceding claim wherein the exit of the water inlet pipe is substantially at the base of the tank.
6. A water heater as claimed in any preceding claim wherein the entrance of the water outlet pipe is sub0antially tt. the top of the tank,
7. A water heater as claimed in any preceding claim wherein a pressure and temperature relief valve is provided with the heater.
8. A water heater as claimed in any preceding claim wherein the space between the housing and the tank is substantially filled with insulating material.
9. A water heater as claimed in any preceding claim wherein a heating element is provided within the tank.
10. A water heater as claimed in Claim 9 wherein the tank is always substantially filled up with water.
11. A water heater as substantially as herein described with reference to the accompanying drawings.