GB2336422A

GB2336422A - Water heating system for sites with no mains water supply

Info

Publication number: GB2336422A
Application number: GB9807749A
Authority: GB
Inventors: Mark Davies
Original assignee: MIDLAND TOILET HIRE Ltd
Current assignee: MIDLAND TOILET HIRE Ltd
Priority date: 1998-04-14
Filing date: 1998-04-14
Publication date: 1999-10-20
Also published as: GB9807749D0

Abstract

In a water heating system, for sites with no mains water supply eg construction sites, comprising a water heater 3, a water tank 15 and a pump 9 for conveying water from the tank to the heater, a switch 17 is provided for de-energising the pump 9 when the water level in the tank 15 falls below a predetermined level. To obtain hot water for washing, a user operates a tap 11 on the heater to open a flow control valve (not shown). The resultant pressure drop at a pressure-sensitive switch (not shown) in the pump 9 causes water to be pumped from the tank 15 through the heater 3 and to be dispensed as hot water through the outlet 13 into a washbasin (not shown). When the flow control valve is closed the pressure-responsive switch turns off the pump. Hot water is supplied on demand, but if the tank 15 should become empty, the float switch 17 cuts in to prevent the pump 9 from running continuously. In case of cold weather, a frost protection thermostat 14 is provided which supplies electrical power to a heated tape (not shown) which is wrapped round various components of the heater to prevent freezing.

Description

2336422 WATER HEATING SYSTEM This invention relates to a water heating

system and is particularly concerned with a water heating system for providing hot water, for example for washing, on transient or permanent sites where a mains water supply is not available.

on construction sites where there is no mains water supply it is conventional practice to provide cold water washing facilities in association with portable toilets. However, there is a demand for hot water washing facilities to be provided and it is therefore an object of the present invention to provide a water heating system which can safely and economically provide hot water in such situations.

According to the present invention there is provided a water heating system comprising:

a water heater having an-inlet and an outlet a tank for containing water; a pump for conveying water from the tank to the inlet of the water heater; and -, 2 switch means for de-energising the pump when the water in the tank falls below a predetermined level.

The pump and the water heater may be mounted on a common back plate. The pump may be provided within a casing removably attached to the back plate. Switch means may be provided to disconnect electrical power to the pump on removal of the casing.

A light may be provided on the casing, for example on the lower face thereof.

The pump may be a centrifugal pump.

A pres sure- sensitive switch may be provided in the water supply between the tank and the water heater for energising the pump on detection of a relatively low pressure. The low pressure arises on opening of a flow control valve in the water heater.

The system may include temperature responsive means, such as a frost thermostat, for energising protective heating means for components of the system in the event of ambient temperature falling below a predetermined value.

For a better understanding of the present invention and to show more clearly how it may be carried into effect reference will now be made, by way of example, to the - 3 accompanying f igure which is a diagrammatic perspective illustration of one embodiment of a water heating system according to the present invention.

The water heating system shown in the drawing comprises a back plate 1 on which is mounted an electric water heater 3 of conventional design in which, for example, water is heated in a tank by means of a submerged heating element and is discharged through a swan neck shaped tube and vortex water nozzle. A number of other components, as will be described in more detail hereinafter, are also mounted on the back plate 1 within a removable casing 5. The removable casing 5 is provided with a lock 7 which operates to disconnect electrical -power to the components within the casing when the casing is removed. Mounted on the lower face of the casing 5 is a light 10 which is operated by a switch (not shown) provided on one side of the casing.

Provided within the removable casing 5 is a power supply 6 including isolating circuit breakers and a transformer for low voltage components..

Water is supplied to the heater 3 by way of a pump 9 provided within the casing 5. The pump 9 may be, f or example, a centrifugal pump. The pump 9 incorporates a pressure- sensitive switch (not shown) which energises the pump when a flow control valve (not shown) operated by a tap 11 on the heater is opened. opening of the flow control - 4 valve results in a pressure drop at the pressure-sensitive switch which, in turn, allows water to flow through the heater in order to be dispensed as hot water through an outlet 13 and into a washbasin or the like (not shown). The pres sure- sens it ive switch also serves to de- energise the pump 9 when the f low control valve is closed with the tap 11.

Also provided within the casing 5 is a frost protection thermostat 14 which, on detecting an ambient temperature fall below a predetermined value, supplies electrical power to a heated tape (not shown) which is wrapped around various components of the heater in order to prevent freezing of any water in those components and consequent damage to the heater in cold weather.

The pump 9 draws cold water from a tank 15 for onward supply to the water heater 3. In order to prevent the pump running continuously when the tank 15 is empty (which would result in a permanent low pressure at the pressuresensitive switch) a level switch 17, such as a float switch, is provided within the tank 15 so as to de-energise the pump 9 when the water level in the tank falls below a predetermined level.

- 5

Claims

1. A water heating system comprising:

a water heater having an inlet and an outlet; a tank for containing water; a pump for conveying water from the tank to the inlet of the water heater; and switch means f or de-energising the pump when the water in the tank falls below a predetermined level.

2. A water heating system as claimed in claim 1, wherein the pump and the water heater are mounted on a common back plate.

3. A water heating system as claimed in claim 2, wherein the pump is provided within a casing removably attached to the back plate.

A water heating system as claimed in claim 3, wherein switch means is provided to disconnect electrical power to the pump on removal of the casing.

A water heating system as claimed in any preceding claim, wherein a light is provided on the casing.

6 - 6. A water heating system as claimed in claim 5, wherein the light is provided on the lower face of the casing.

7. A water heating system as claimed in any preceding claim, wherein the pump is a centrifugal pump.

8. A water heating system as claimed in any preceding claim, wherein a pres sure- sens it ive switch is provided in the water supply between the tank and the water heater for energising the pump on detection of a relatively low pressure.

A water heating system as claimed in claim 8, wherein the low pressure arises on opening of a flow control valve in the water heater.

10. A water heating system as claimed in any preceding claim and including temperature responsive for energising protective heating means for components of the system in the event of ambient temperature falling below a predetermined value.

A water heating system as claimed in claim 10, wherein the temperature responsive means comprises a frost thermostat.

12. A water heating system substantially as hereinbefore described with reference to, and as shown in, the accompanying drawing.