GB2127141A - Heater system - Google Patents

Abstract

A heater system having improved fuel consumption has a water boiler 32 heated by a burner 10 supplied with oil by pump 14 through an entrainment device 12' in which flow of oil entrains water from line 31. A solenoid water flow control valve 21 and pump motor 15 are responsive to boiler steam pressure to operate between pressure limits. In one arrangement the burner has high and low flame and water is added to the fuel only when operating at high flame. <IMAGE>

Description

SPECIFICATION Improvements in or relating to heater systems and methods of operating same This invention relates to heater systems and methods of operating heater systems.

It is desirable to improve the fuel consumption of heater systems incorporating a burner.

According to one aspect of this invention a heater system comprises a burner, a boiler for liquid heated by the burner, means for supplying liquid fuel to the burner, and means for adding another liquid to the fuel prior to combustion in response to pressure of gas and/or vapour from said boiler. The boilder may be a water boiler, the adding means being responsive to steam pressure.

The other liquid is preferably non-combustible.

The other liquid may be substantially immiscible with the liquid fuel.

Preferably, said means for adding comprises a device in which flow of fuel entrains said other liquid.

The fuel may for example be oil and the other liquid may for example be water.

The system may comprise a flow control device for controlling the flow of the other liquid from a supply to the adding means.

In one arrangement air is fed buy a blower to the burner for combustion with the fuel.

The burner may be constructed to have a high flame or a low flame, and means may be provided to render said adding means operative only when the burner is operating at high flame.

According to another aspect of the invention a method of operating a heater system in which liquid fuel is supplied to a burner which heats liquid in a boiler comprises adding another liquid to pressure of gas and/orvapourfrom said boiler.

The invention may be performed in various ways and two specific embodiments with possible modifications will now be described by way of example with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a heating system; Figure 2 is another heating system; and Figure 3 is a modification of the system of Figure 2.

In the system of Figure 1 an oil burner 10 receives oil from combustion through fuel pipe 11 with burner nozzle 12 receiving fuel oil through connector 12' and line 13from pump 14 driven by electric motor 15 and drawing oil from a source (not shown) through line 16.

The burner has a head or nozzle 12 where the fuel is burnt or combusted with air.

The air may be supplied as an axial flow through line 17 by blower 18 driven by motor 15.

A pressure gauge may be connected to one or more of the flow pipes or lines as desired to indicate the relevant liquid pressure.

A line 20 is connected to mains water supply and to an on/off solenoid-operated flow control valve 21.

A pressure gauge 22 indicates the water pressure in the line 20. A line 23 connects the valve 21 to a manually operable flow regulator 24 connected through line 25 to a flow meter 26 itself connected through line 27 to a one-way check valve 28 leading through a line 29 to another one-way check valve 30 having an outlet connected through line 31 to the connector 12. Valve 28 allows flow from line 27 to line 29 but not in the opposite direction; valve 30 allows flow from line 29 to line 31 but not in the opposite direction.

Thus water and fuel oil are fed to the burner pipe 12.

The pressure of oil delivered by the pump 14 may for example be 200 to 300 pounds per square inch (1379 kilopascals to 2068 kilopascals) and the water pressure in line 20 may for example be 50 pounds per square inch (345 kilopascals). The flow of oil from the pump 14through the connector 13' to the pipe 11 will draw in or entrain with it water from line 31 and line 29. The one-way valve 30 prevents oil passing into the water circuit, and one-way valve 28 provides an additional safe-guard in this respect.

In one arrangement the water flow may be at say 200 cubic centimetres per minute and form about 18% of the total liquid flow to the burner in line 11. It is found that the heat output of the burner is not substantially less than if the whole liquid flow is fuel oil, resulting in a reduction in fuel consumption of about 18%. The flow regulator 24 enables the water flow to be adjusted.

In one arrangement using 3500 seconds oil the proportion of water in line 11 may be 21% by volume.

The burner is associated with a steam boiler 32 including an electric switch 33 responsive to steam pressure in the boiler, for example a switch incorporating a tiltable tube of mercury. The switch 33 is operatively connected to the motor 15 and the valve 21 and is arranged to deenergize the motor 15 and close the valve 21 when the steam pressure is at a predetermined, upper, limit and to open valve 21 and energize motor 15 art a predetermined, lower, limit. The switch 33 may be adjustable to vary these limits.

In an installation, with a particular fuel oil, the regulator 24 would be initially adjusted to give a suitable water flow in relation to the oil flow and the remain in the adjusted position. Different positions of adjustment may be advantageous for different fuel oils. The motor 15 typically runs at a constant speed and the oil pressure is initially adjusted and is then constant, although the mains pressure may vary slightly.

The invention may be used with other kinds of burner. For example in Figure 2 the burner 50 has a high flame nozzle 12 associated with pipe 11 and a low flame nozzle 51 receiving oil from pump 14 through line 52. The motor 15 drives blower 18 at a constant speed and combustion air is delivered to the burner through line 53 including adjustable shutters 54 to control the air flow. Line 13 in this case includes solenoid-operated flow control valve 55 arranged so that when switch 33 opens valve 21 valve 55 is also opened to supply pressure oil in line 13 (pressure oil continuing to be supplied in line 52) to connector 12' and also to ram 56 to open shutters 54 through linkage 57 to allow greater air flow and also to open valve 58 in the water supply circuit through linkage 59.When switch 33 closes valve 21 valve 55 also closes and a spring returns the ram 56 closing valve 58 and moving the shutters 54to the low-flow condition.

In this case the motor 15 is under the control of a manually operable on/off switch 60.

In the modification of Figure 3, the pump 14 supplies oil to burner chamber 60 and low-flame nozzle 61. Oil is also supplied through valve 70 to chamber 65. High-flame nozzle 62 is normally closed by valve number 63 under oil pressure in chamber 65. When switch 33 opens valve 21, valve 70 is moved and the suction side of the pump is connected through line 71 and valve 70 to one side of the ram 56 and spring 65 moves the ram to open the shutters and valve 58, and spring 72 moves valve member 63 to open high flame nozzle 62. In Figures 2,3 water is supplied only when the burner is on high-flame.

In the described arrangements, the motor could be additionally switched on and off by a time-controlled switch.

Conventional oil-preheating devices and flame ignition devices are provided and flame or tempera- ture responsive means are arranged to switch off the motor and close valve 21 if there is no flame at 12 or the low flame 51.

One suitable burner is made by Nu-way Limited of Droitwich, including conventional associated parts and controls (not shown). A suitable boiler is made by John Thompson & Co. Ltd. of Glasgow. Other forms of burner or burner system may be used, for example gas turbine burners.

The switch 33 need not be responsive to the steam pressure in the boiler but could for example be responsive to steam pressure in a pipe or apparatus supplied by the boiler.

Flowmeter 26 comprises vertical inlet and outlet tubes 80, 81, a cylindrical housing 82 including a front window carrying a linear scale 83. The tubes 80,81 are connected by a transparent tube 84 in which is located a ball bearing 85 which rises or falls in response to the water pressure and the flow rate in tube 84. The flow rate can be read off from the scale 83. When there is now water flow, the bearing 85 falls to the bottom of tube 84 where it rests on a shoulder.

It is thought that the heat of the burner flame may possibly atomize the water, with subsequent combustion of the hydrogen and oxygen, although the water itself is non-combustible.

It is thought that other non-combustible liquids could be used instead of water.

It will be appreciated that the parts for the water supply could be added as a modification to suitable existing burner systems.

Other means for continuously adding the water to the fuel flow can be used than the hollow entraining device 12 having two passages at right angles. The bores of the stem and cross passage of T-piece 12 are equal and equal to the bores of pipes 13,31, 11.

Claims (13)

1. A heater system comprising a burner, a boiler for liquid heated by the burner, means for supplying liquid fuel to the burner, and means for adding another liquid to the fuel prior to combustion in response to pressure of gas and/or vapour from the boiler.

2. A heater system as claimed in claim 1, in which the boiler is a water boiler, and the adding means is responsive to steam pressure from the boiler.

3. A heater system as claimed in claim 1 or claim 2, in which the other liquid may be non-combustible.

4. A heater system as claimed in any preceding claim, in which the other liquid is substantially immisible with the liquid fuel.

5. A heater system as claimed in any preceding claim, in which the means for adding comprises a device in which flow or fuel entrains said other liquid.

6. A heater system as claimed in any preceding claim, in which the fuel is oil and the other liquid is water.

7. A heater system as claimed in any preceding claim, including a flow control device for controlling the flow of the other liquid from a supply to the adding means.

8. A heater system as claimed in any preceding claim, in which the burner is constructed to have a high flame and a low flame and means are provided to render the adding means operative only when the burner is operating on high flame.

9. A heater system substantially as hereinbefore described with reference to and as shown in Figure 1, or Figure 2, or Figure 3, of the accompanying drawings.

10. A method of operating a heater system in which liquid fuel is supplied to a burner which heats liquid in a boiler comprising adding another liquid to the fuel prior to combustion in response to pressure of gas and/or vapour from the boiler.

11. A method as claimed in claim 10, in which the other fuel is added to the fuel by entrainment.

12. A method as claimed in claim 10 or claim 11, in which the boiler pressure is steam pressure.

13. A method of operating a heater system substantially as hereinbefore described.