GB2220052A - Water heater for caravans - Google Patents

Abstract

A water heater for use in a caravan comprises a water tank 14 with water inlet 16 and outlet 17, and a gas-fired heat exchanger 18 within the tank and provided with an exhaust flue 21 at, adjacent or below the bottom of the tank. A water-flow heat exchanger 28 is fitted within the tank, preferably surrounding the gas-fired heat exchanger, and has a water inlet 29 and outlet 30. The water tank inlet and outlet are connected to one or more central heating radiators, and the water flow heat exchanger provides the caravan domestic water supply. As a result there is provided a small compact water heater for use in a caravan and capable of providing hot water both for central heating and domestic usage purposes. <IMAGE>

Description

A WATER HEATER The invention relates to water heaters especially but not exclusively suitable for use in caravans (towed or self propelled), small watercraft and other locations where space is limited.

For convenience reference will be made hereinafter and in the claims simply to "caravans".

It is an object of the present invention to provide a small compact water heater for use in a caravan and capable of providing hot water both for central heating and domestic usage purposes.

According to the present invention there is provided a water heater for use in a caravan and comprising a water tank with water inlet and outlet, a gas-fired heat exchanger within the tank and provided with an exhaust flue at, adjacent or below the bottom of the tank, and a waterflow heat exchanger within the tank, and preferably surrounding the gas-fired heat exchanger, and with water inlet and outlet.

Preferably the gas-fired heat exchanger is centrally disposed within the tank with a central combustion chamber within which is disposed the gas burner of a fan-assisted gas burner assembly disposed underneath the tank. When fitted in a caravan the fan-assisted gas burner assembly is preferably disposed under the caravan floor, i.e. external of the caravan.

Preferably the combustion chamber is surrounded by a helically arranged heat exchange pipe or tube terminating in an exhaust pipe adapted to extend underneath the caravan floor and to one side of the caravan. The exhaust pipe is preferably pivotal to permit the exhaust gases to be directed to a safe location.

Preferably the fan-assisted gas burner assembly comprises a flat centrifugal air supply fan connected by a pipe or duct to the gas burner, there being a tangentiallydisposed gas supply inlet in the pipe or duct.

The gas burner may be a closed-end tubular body formed of wire gauge, or it may be formed of adjacent alternate flat and corrugated metal strips wound into a coiled configuration as is disclosed in our copending Patent Application No. 8801785 filed January 27, 1988.

Preferably the water flow heat exchanger is a coiled tube, preferably externally finned, surrounding the gasfired heat exchanger.

Preferably the water tank inlet and outlet are connected to one or more central heating radiators.

Preferably the water flow heat exchanger provides the caravan domestic water supply.

The gas burner assembly is preferably fitted with a flame rectification ignition system.

The water tank is preferably of square or rectangular configuration to permit it to be readily stowed under a shelf or other convenient caravan furniture fixture.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawing, in which: Fig. 1 is a part-sectional elevation in the vertical plane of caravan water heater according to this invention; Fig. 2 is a sectional view on the line II-II of Fig.

1; Fig. 3 is a plan and detail view of the alternative gas burner assembly.

Referring to the drawing, the floor of a caravan is indicated at 10, a vertical wall of the caravan at 11 and an internal shelf or other furniture fixture at 12.

The water heater generally indicated at 13 comprises a square box-shaped water tank 14 enclosed by insulation 14A and provided with a top pipe 15 which serves as a water top-up point.

The water tank 14 has a bottom water inlet 16 and a top water outlet 17 connectible to one or more heating radiators (not shown) provided in the caravan for central heating purposes.

The water tank 14 has a centrally-disposed gas-fired heater exchanger 18 comprising a central combustion chamber 19 cpen at the bottom and spatially surrounded by a helically-arranged heat exchanger tube 20, whereof the gas flow is from top to bottom. The heat exchange tube 20 at its bottom end is connected to an exhaust pipe 21 which extends down through the floor 10 and then at righ-t angles to the caravan side thus removing exhaust gases from belpw the caravan to the free atmosphere at the caravan side.

The exhaust pipe 21 may be rotatably fitted to the heat exchange tube 20 to permit the exhaust direction to be selected by the caravan user.

A fan-assisted gas burner assembly 22 is provided for the heat exchanger 18 and comprises a gas burner 23 disposed inside the combustion chamber 19, a relatively flat air supply centrifugal fan 24 below the floor 11 externally of the caravan, and a duct or pipe 25 connecting the fan 24 and the burner 23.

A gas supply inlet pipe 26 is fitted to the duct or pipe to provide a tangential inflow of gas (natural7 propane or butane) in the airstream flowing from the fan 24 to the burner 23 (see Fig. 2). This tangential gas supply causes a swirling mixing effect between the gas and the air to provide a uniform homogenous gas/air mixture for the burner 23.

The gas burner is provided with a flame rectification ignition system (not shown).

Within the tank 14 and surrounding the heat exchanger 18 is a water flow heat exchanger 27 constituted by a helically-arranged, externally finned tube 28 having a water inlet 29 and a water outlet 30. This provides the domestic water supply for the caravan.

The heat exchange efficiency of the water heatcr described above is considered to be of the order of 85 to 95%.

Any condensing which takes place during combustion will be exhausted along with the exhaust gases through the flue pipe 21.

Referring to Fig. 3, the alternative gas burner assembly comprises a gas burner 23A having connected thereto a relatively fiat air supply centrifugal fan 24A via a duct 25A. The gas burner porting 31 is constituted by adjacent alternate flat and corrugated metal strips 32, 33 wound into a coiled configuration.

Claims (20)

1. A water heater for use in a caravan ancj. or,prising a water tank with water inlet and outlet, a cas-fired heat exchanger within the tank and provided with an exhaust flue at, adjacent or below the bottom of the tank, and a waterflow heat exchanger within the tank and with water inlet and outlet.

2. A water heater as claimed in claim 1 in which the water flow heat exchanger surrounds the gas-fired heat exchanger.

3. A water heater as claimed in claim 1 or 2 in which the gas-fired heat exchanger is centrally disposed within the tank with a central combustion chamber within which is disposed the gas burner of a fan-assisted gas burner assembly disposed underneath the tank.

4. A water heater as claimed in claim 3, in which the combustion chamber is surrounded by a helically arranged heat exchange pipe or tube terminating in an exhaust pipe adapted to extend, when the water heater is fitted in a caravan, underneath the caravan floor and to one side of the caravan.

5. A water heater as claimed in claim 4 in which the exhaust pipe is pivotal to permit the exhaust gases to be directed to a safe location.

6. A water heater as claimed in any one of claims 3 to 5, in which the fan-assisted gas burner assembly comprises a flat centrifugal air supply fan connected by a pipe or duct to the gas burner, there being a tangentiallydisposed gas supply inlet in the pipe or duct.

7. A water heater as claimed in any one of claims 3 to 6, in which the gas burner is a closed-end tubular body formed of wire gauge.

8. A water heater as claimed in any of claims 3 tc 6, in which the gas burner is formed of adjacent alternate flat and corrugated metal strips wound into a coiled configuration.

9. A water heater as claimed in any one of claims 1 to 8 in which the water flow heat exchanger is a coined tube, preferably externally finned, surrounded t gas- fired heat exchanger.

10. A water heater as claimed in any one of claims 1 to 9, in which the water tank inlet and outlet are connected to one or more central heating radiators.

11. A water heater as claimed in any one of claims 1 to 10 in which the water flow heat exchanger is adapted to provide the caravan domestic water supply.

12. A water heater as claimed in any one of claims 3 to 11 in which the gas burner assembly is fitted with a flame rectification ignition system.

13. A water heater as claimed in any one of claims 1 to 12 in which the water tank is of square or rectangular configuration to permit it to be readily stowed under a shelf or other convenient caravan furniture fixture.

14. A water heater for use in a caravan, substantially as hereinbefore described with reference to Figs. 1 and 2 or Figs. 1 and 2 as modified by Fig. 3 of the accompanying drawings.

15. A caravan fitted with a water heater as claimed in any one of claims 1 to 14.

16. A caravan as claimed in claim 15 in which the gas burner assembly is disposed underneath the caravan floor external of the caravan.

17. A caravan as claimed in claim 15 or 16 in which the exhaust pipe, which is preferably pivotal, extends out of the caravan under the caravan floor and to one side thereof.

18. A caravan as claimed in any one of claims 15 to 17 fitted with at least one central heating radiator to which the water tank inlet and outlet are connected.

19. A caravan as claimed in any one of claims 15 to 18 having a domestic water supply into which is connected the water flow heat exchanger.

20. A caravan as claimed in any one of claims 15 to 19 in which water tank is stowed under a shelf or other furniture fixture of the caravan.