GB2226397A - Adding water to fuel oil - Google Patents

Abstract

An apparatus to add water to fuel oil supplied to a combustion zone of oil burning equipment comprises means to produce a binary number signal representing the rate of supply of said oil to regulate the water supply to the oil prior to combustion. Preferably the water is selectively supplied by two or more valves 52A to 52D in parallel at respective flow rates corresponding to successive powers of the binary digit base eg at a ratio of 1:2:4:8. <IMAGE>

Description

APPARATUS FOR ADDING WATER TO FUEL OIL This invention relates to apparatus for adding water to fuel oil for combustion in oil burning equipment.

The apparatus is for connection to a water supply and to oil burning equipment, for example an oil fired boiler, and has particular but not exclusive application to the supply of fuel oil to industrial boilers and steam generators.

The addition of water to fuel oil can promote combustion and economy provided care is taken that the quantity added is not so high that combustion is prevented.

According to the invention an apparatus to add water to fuel oil supplied to a combustion zone of oil burning equipment comprises fuel oil supply means to convey fuel oil to said combustion zone, said fuel oil supply means comprising rate of oil supply regulating means whereby the rate at which oil is supplied to the zone can be varied, means to produce a signal representing a binary number which is a function of the rate of the supply of said oil, water supply means to add water to the oil prior to combustion of said oil, the water supply means comprising water supply rate regulating means to vary the rate at which the water is added, and the water supply rate regulating means being arranged so that water is added at a rate which is a function of the value of the binary number.

The water supply rate regulating means can be arranged so that water is added at a rate which is substantially the product of a multiplier and a multiplicand of which the multiplicand is substantially a constant and the multiplier is a decimal number of a value substantially equal to the binary-to-decimal conversion of said binary number.

The water supply regulating means may comprise a plurality of water flow paths each openable and -closable, each flow path when closed corresponding to the binary digit "0" and when open to the binary digit "1", each flow path whether closed or open corresponding to a respective different power of the base - 2 known in positional notation for representing binary numbers such that each possible combination of open or closed said flow paths corresponds to a different binary number, each flow path when open allowing passage therethrough of water at a rate substantially equal to the product of a multiplicand which is substantially constant for all the said flow paths and a multiplier having a decimal number value equal to said power of the base - 2 corresponding to the flow path, and the water supply regulating means being arranged so that the flow paths are opened or closed in correspondence with the binary number represented by said signal.

The number of flow paths may be two or more.

For example if there are four flow paths, the rate at which water can flow along the first flow path is predetermined and may be said multiplicand and the arrangement may be such that the rate at which water can flow along: (i) the fourth flow path is substantially eight times that along the first path; (ii) the third flow path is substantially four times that along the first path; (iii) the second flow path is substantially twice times that along the first path; wherein the first flow path corresponds in binary number positional notational to the position 20 (decimal number 1), the second flow path corresponds to the position 21 (decimal number 2), the third flow path corresponds to position 22 (decimal number 4), and the fourth flow path corresponds to position 23 (decimal number 8).

Each flow path may comprise respective regulator means arranged to set a predetermined flow rate along that path.

Each flow path may comprise respective valve means operable in response to said signal to open or close to allow or stop flow along the path.

The input of water to said flow paths may be an output from water metering means which may be arranged to give a constant output which is variable with demand, and may be at a predetermined substantially constant pressure.

The binary signal may be an electrical binary signal derived from an analogue to binary converter to which is input an analogue signal being a function of the rate of fuel oil supply. The analogue signal may be derived from apparatus regulating the rate of oil supply and may correspond to the position of a fuel control valve.

The fuel control valve may be opened and closed by drive from motor means responding to control signals demanding variation in the rate of oil supply. Such control signals may be initiated by detector means observing a phenomonon related to the heat generated by the burning oil, for example the detection means may be a thermostat or, perhaps in the case of equipment producing steam, a steam pressure transducer.

The analogue signal may be an electrical signal having a value which is a function of the position of a moving slider of potentiometer in which the slider is moved in response to movement of the fuel control valve or of the motor or of other apparatus regulating the rate of oil supply. Return spring means may urge the slider towards one end to potentiometer's resistance range. The position of the slider may be determined by a cord or cable attached at one end to the slider and wound at the other end on a drum or pulley rotated in either direction accordingly by movement of the regulating apparatus winding in the cord or cable in opposition to the spring means or paying out the cord etc. Use of the cord or cable reduces the chance of disturbing vibrations being transmitted to the potentiometer from the moving regulating apparatus, for example the motor.

Indicating means may be provided to indicate the rate at which water is being supplied to the oil and/or which valves or flow paths are open or closed.

The invention will now be further described, by way of example, with reference to the accompanying drawing diagrammatically illustrating an embodiment of apparatus formed according to the invention.

In the drawing a pipe 20 feeds fuel oil at appropriate pressure in the direction of arrow X to the combustion chamber (not shown) of oil fired equipment, the rate at which the oil is supplied being controlled by oil control valve 22 opened or closed to the desired extent by drive from an electric motor 24 operated in response to an electric control signal 26 indicating the amount of demand for fuel. In correspondence with the valve, the motor also drives potentiometer 28 giving an electrical output signal 30 having an analogue value which is a function of rate of supply of the oil.

Converter 32 converts the analogue value to an electrical, binary output signal 34 which is a function of the rate of supply of the oil. The binary signal is input to a display driver 36 and to a solenoid driver 38.

Water flowing in direction Y is added to the oil flow in the pipe 20 through a pipe 40 which may include a non-return valve 42. Preferably the water is added close to the combustion zone, and a suitable device may be provided in the pipe 20 at or downstream of the pipe 40 to improve the mixing of the water with the oil and increase the chance of an emulsion of small water drops in oil being formed.

Branching into pipe 40 are four water flow pipes 44A, 44B, 44C and 44D which branch from a pipe 46 carrying the output water from a water meter 48 fed with input water by pipe 50 from a suitable supply.

The meter 4 (known per se) gives an output at any desired predetermined pressure, this meter being arranged to give a constant output rate when demand for output water is constant but which varies to meet the demand when the latter varies.

Each flow pipe has a respective solenoid controlled water valve 52A, 52B, 52C or 52D accordingly, and a corresponding water flow regulator 54A, 54B, 54C or 54D. Each water valve is either in fully closed condition or fully open condition according to the energy state of its solenoid. Each flow regulator is adjustably variable to allow a different flow rate along each of the pipe 44A, 44B, 44C or 44D. For example if the regulator 44A is set to allow a flow rate of t along pipe 44A when valve 52A is open, regulator 54B is set to allow a flow rate along pipe 44B of 2 X , regulator 44C allows a flow rate in pipe 4 X , and regulator 44D allows a flow rate of 8 in pipe 44D.

Therefore each pipe 44A ... 44D corresponds to respective successive power of the base - 2 in the positional notational system of binary numbers and the condition of each valve 52A ... 52D represents the coefficient of the corresponding aforesaid power; closed condition representing binary digit '0" and the open condition binary digit " When all the water flow valves are closed the state of the system of pipes 44, valves 52 and regulators 54 corresponds to binary number 0000, when only valve 52A is open the system corresponds to binary number 0001, when only valve 52B is open the correspondence is its binary number 0010, when only valve 52B is open the correspondence is to binary number 0100, and when only valve 52D is open the correspondence is to binary number 1000.Thus according to which water flow valves are closed or open the state of the system 44, 52, 54 can correspond to any binary number in the range 0000 to 1111.

The binary signal 34 can represent any binary number in the range 0000 up to 1111 depending if flow rate of the oil, the greater the flow rate- the greater the binary number. The mathematical relationship between binary number and oil flow rate may be substantially linear. In response to the binary signal 34 the solenoid driver causes the water valves of the flow pipes corresponding to that binary number to be open.If the binary signal 34 is 0000 all valves 52 are closed, if the signal 34 is 1111, all valves 52 are open and water is supplied to pipe 40 for addition to the oil at a rate of 15X . If the signal 34 is of some intermediate binary value for example 0011, only the water valves corresponding to that intermediate value open, for example the valves 52A and 52B, providing a supply of water to be added to the oil at rate equal to the binary to decimal conversion multiplied by X , for example sX in the case of signal 34 representing binary number 0011.

The display driver 36 drives a seven segment digital display 56 showing in decimal numbers at any instant the binary to decimal conversion of the signal 34 and thereby providing indication of which valves 52 are open and the amount of water being added to the oil. Driver 36 may also drive another display 58, for example a bargraph display, which may indicate in units of volume per unit time the rate at which water is being added.

The arrangement may be such that at the time of initial ignition of the oil and/or at a low firing, no water is added.

Claims (14)

1. An apparatus to add water to fuel oil supplied to a combustion zone of oil burning equipment comprises fuel oil supply means to convey fuel oil to said combustion zone, said fuel oil supply means comprising rate of oil supply regulating means whereby the rate at which oil is supplied to the zone can be varied, means to produce a signal representing a binary number which is a function of the rate of the supply of said oil, water supply means to add water to the oil prior to combustion of said oil, the water supply means comprising water supply rate regulating means to vary the rate at which the water is added, and the water supply rate regulating means being arranged so that water is added at a rate which is function of the value of the binary number.

2. An apparatus according to Claim 1, wherein the water supply rate regulating means is arranged so that water is added at a rate which is substantially the product of a multiplier and a multiplicand of which the multiplicand is substantially a constant and the multiplier is a decimal number of a value substantially equal to the binary-to-decimal conversion of said binary number.

3. An apparatus according to Claim 2, comprising a plurality of water flow paths each openable and closable, each flow path when closed corresponding to the binary digit 'lo'l and when open to the binary digit "1", each flow path whether closed or open corresponding to a respective different power of the base - 2 known in positional notation for representing binary numbers such that each possible combination of open or closed said flow paths corresponds to a different binary number, each flow path when open allowing passage therethrough of water at a rate substantially equal to the product of a multiplicand which is substantially constant for all the said flow paths and a multiplier having a decimal number value equal to said power of the base - 2 corresponding to the flow path, and the water supply regulating means being arranged so that the flow paths are opened or closed in correspondence with the binary number represented by said signal.

4. An apparatus according to Claim 3, comprising four flow paths, wherein the rate at which the water can flow along the first flow path is said multiplicand and the arrangement is such that the rate at which water can flow along: (i) the fourth flow path is substantially eight times that along the first path; (ii) the third flow path is substantially four times that along the first path; (iii) the second flow path is substantially two times that along the first path; and wherein the first flow path corresponds in binary number notation to the position 20 (decimal number 1), the second flow path corresponds to the position 21 (decimal number 2), the third flow path corresponds to position 22 (decimal number 4), and the fourth flow path corresponds to position 23 (decimal number 8).

5. Apparatus according to any preceding claim, wherein each flow path comprises respective regulator means arranged to set a predetermined flow rate along that path.

6. Apparatus according to any preceding claim, wherein each flow path comprises respective valve means operable in response to said signal to open or close to allow or stop flow along the path.

7. Apparatus according to any preceding claim, wherein the input of water to said flow paths is an output from water metering means which is arranged to give a constant output which is variable with demand, and is at a predetermined substantially constant pressure.

8. Apparatus according to any preceding claim, wherein the binary signal is an electrical binary signal derived from an analogue to binary converter to which is input an analogue being a function of the rate of fuel oil supply.

9. An apparatus according to Claim 8, wherein the analogue signal is derived from apparatus regulating the rate of oil supply and corresponds to the position of a fuel control valve.

10. An apparatus according to Claim 9, wherein the fuel control valve is opened and closed by drive from motor means responding to control signals demanding variation in the rate of oil supply.

11. An apparatus according to Claim 10, wherein the control signals are initiated by detector means observing a phenomonon related to the heat generated by the burning oil.

12. An apparatus according to Claim 8, 9, 10 or 11, wherein the analogue signal is an electrical signal having a value which is a function of the position of a moving slider of a potentiometer in which the slider is moved in response to movement of the fuel control valve.

13. An apparatus according to Claim 12, wherein the position of the slider is determined by a cord or cable attached at one end to the slider and wound at the other end on a drum or pulley rotated in either direction accordingly by movement of the regulating apparatus.

14. An apparatus substantially as hereinbefore described with reference to the accompanying drawing.