Means and method of optimizing efficiency of furnaces, boilers, combustion ovens and stoves, and the like

• US 4,676,734 A
• Filed: 05/05/1986
• Issued: 06/30/1987
• Est. Priority Date: 05/05/1986
• Status: Expired due to Term

• Current Assignee: Patrick J. Foley
• Original Assignee: Patrick J. Foley
• Inventors: Foley, Patrick J.
• Primary Examiner(s): Favors, Edward G.
• Application Number:
  US06/859,827
• Time in Patent Office: 421 Days
• Field of Search: 431/2, 431/12, 110/341, 110/186, 110/190, 236/15 E, 236/15 BD
• US Class Current: 431/12
• CPC Class Codes: F23N 1/022 using electronic means
• CPC Class Codes: F23N 2225/14 Ambient temperature around burners
• CPC Class Codes: F23N 2235/04 in stacks
• CPC Class Codes: F23N 2235/06 at the air intake
• CPC Class Codes: F23N 2235/12 Fuel valves
• CPC Class Codes: F23N 2241/10 Generating vapour

Abstract

A means and method for optimizing the efficiency of combustion devices such as furnaces, boilers, ovens, stoves, and the like which automatically tests for and controls the amount of input air utilized by the combustion device to optimize combustion efficiency. The method constantly increases or decreases the amount of input air and monitors the output of the combustion device to see if the change in input air increases or decreases efficiency. If efficiency is increased, the amount of input air is continued to be changed in that direction. If the efficiency is decreased, the change of excess air is reversed. By continuously testing for optimal air fuel ratios, optimal efficiency is reached. The means to accomplish the method include an output monitor, an air input control means, and recording means for recording the output of the combustion device as it presently exists compared to its former reading. A math unit then compares the two readings and depending upon whether output is increased or decreased, utilizes a logic control to signal a switching means which sends a signal to either increase or decrease the input air to the air control means. The means and method can be utilized with combustion devices having variable fuel and air input, or with combustion devices which have a fixed fuel input or which must output at a fixed level.

Claims

1. A method of optimizing efficiency of a combustion device such as a furnace, boiler, oven, stove or the like wherein required combustion device output is variable and fuel input is variable, comprising:

monitoring the rates of fuel input and combustion device output of said combustion device;

obtaining first readings of fuel input and combustion device output;

dividing said first combustion device output reading by said first fuel input reading to derive a first quotient of combustion device output to fuel input;

increasing the air input by a first amount to said combustion device;

obtaining second readings of combustion device output and fuel input;

dividing said second combustion device output reading by said second fuel input reading to derive a second quotient of combustion device output to fuel input;

recording said second quotient;

subtracting said first quotient from said second quotient to derive a remainder representing change in rate of combustion device output for said combustion device;

increasing input air again if said remainder is positive and the excess air level was previously increased;

decreasing input air if said remainder is negative and the excess air level was previously decreased;

if the remainder is negative and the excess air level was previously increased, the excess air level is then decreased; and

if the remainder is negative and the excess air level was previously decreased, the excess air level is then increased.

2. The method of claim 1 wherein said air input is always reset to an initial air increase setting before the method is begun.

3. The method of claim 1 wherein when said remainder alternates between negative and positive, said first time period is incrementally reduced.

4. The method of claim 2 comprising the further step of resetting said incremental air changes to said increased setting if said remainder is equal to zero, and the excess air level previously was decreased.

5. The method of claim 1 wherein if excess air was increased or decreased and was trimmed and the remainder results in zero or close to zero, the increment changes are stopped and output and input are monitored for a negative value.

6. The method of claim 5 wherein the incremental changes in the excess air level are restarted after a negative remainder.

7. The method of claim 1 wherein said second quotient is derived only after waiting a sufficient time period for said output to stabilize to the change in input air.

8. The method of optimizing combustion efficiency in combustion devices such as furnaces, boilers, stoves, ovens, and the like, wherein said combustion device has a fixed fuel supply and produces an output having a temperature component, comprising the steps of:

initiating combustion in said combustion device by inputting said fixed supply of fuel, introducing an initial amount of input air, and instigating combustion;

monitoring said output of said combustion device;

recording for subsequent comparison a first output reading for said combustion device;

increasing the amount of combustion air from said initial setting entering said combustion device;

recording a second output reading;

subtracting said first output reading from said second output reading;

increasing the amount of combustion air again if the remainder between said second output reading and said first output reading is positive or zero;

decreasing the amount of combustion air if the remainder between said second output reading and said first output reading is negative;

thereby increasing or decreasing the combustion air to maximize output of said combustion device as the fixed fuel supply is used up.

9. The method of claim 8 wherein the time period between increasing the amount of excess air and recording a second output reading is adjustable.

10. A method of operating a combustion device such as a furnace, boiler, stove, oven or the like at a desired output by inputting variable amounts of fuel to maintain said desired output, comprising the steps of:

monitoring the rate of fuel input of said combustion device;

recording a first rate of fuel input reading;

increasing the air being input to said combustion device from the initial air input level;

recording a second rate of fuel input reading;

subtracting the second rate of fuel input reading from the first rate of fuel input reading to derive a remainder representing the change in fuel input;

increase air input into the combustion device if the remainder is positive and repeating increase in air input if the remainder is positive;

decreasing the air input into said combustion device if the remainder is negative;

repeating the decrease in air if said remainder is positive; and

increasing the air input in the remainder is negative or zero after previously decreasing input air.

11. A means for optimizing efficiency of a combustion device such as a furnace, boiler, oven, stove and the like, wherein the input fuel supply and input air supply is variable, comprising:

an output monitoring means for continuously deriving output levels of said combustion device;

an input monitoring means for continually monitoring fuel input to said combustion device;

air control device means operatively connected to the means for controlling air input into said combustion device for controlling the exact amount of said input air into said combustion device;

means to convert the readings for fuel input and output into electrical signals representing fuel input and output;

divider math unit means in electrical communication with said output and input reading means for dividing said output reading by said fuel input reading to derive a ratio of combustion device output to fuel input;

a first signal storage means in electrical communication with said divider means for storing a present output ratio of said divider means, and being updatable upon each division of said divider means;

a second signal storage means in electrical communication with said divider means which stores a past output ratio of said divider means, and has a electronic means to hold said past output ratio until said second storage means is updated;

a math unit subtracter means for subtracting the contents of said second signal storage means from said first signal storage means to derive a remainder representing a change between said present output ratio and said past output ratio, said subtracter means being in electrical communication with said first and second storage means;

a math unit logic means in electrical communication with said subtracter means which produces a signal if the said remainder of said subtracter means is negative and does not produce a signal if said remainder is positive;

an electronic switching means in electrical communication with said logic means and said air control bias means for directing said air control bias means to either increase air input or decrease air input into said combustion device, said switching means having an increased air state which sends an increased air input signal to air control bias, and a decrease air state which sends a decrease air input signal to said air control bias, said switching means being initially in said increase air state and continuing in said increase air state until said signal is received from said logic means which would switch said switching means to said decrease air state, any said signal from said logic means switching the states of said switching means; and

timing means to control sequencing of the elements of the means.

12. The means of claim 11 wherein said logic means further comprises means to send a signal to said switching means if said remainder of said subtracter means equals zero and said switching means is in said decrease air state.

13. The means of claim 11 further comprising manual adjustable means for determining the amount of change in said air control bias to either increase or decrease air input.

14. The means of claim 11 further comprising a trimmer means for automatically decreasing the amount of change signalled by said dwell means to constantly reduce the amount of air increase or air decrease signalled by said switching means.

15. A means for optimizing efficiency of a combustion device such as a furnace, boiler, oven, stove, and the like wherein the amount of fuel input is fixed, comprising:

a motor means operatively connected to the air damper of said combustion device for moving said air damper between a minimum and maximum air input position;

an output reading means operatively connected to said combustion device to derive a representation of output of said combustion device;

a transducer means to convert the output readings of said output reading means into an electrical signal;

a first electronic signal storage means in electrical communication with said output transducer means for storing a present output reading signal;

a second electronic signal storage means in electronic communicaton with said first storage means for storing a past output reading;

a clock means in electronic communication with said second electronic signal storage means which causes said second storage means to hold an output reading until a subsequent signal is entered into said first electronic signal storage means, so that said second storage means always contains the immediately prior output reading to that of the first storage means;

a math unit subtracter means in electrical communication with said first and second storage means for subtracting the past reading of said second storage means from the present reading of said first storage means to derive a remainder representing the change in output of said combustion device;

a logic means in electrical communication with said subtracter means which generates an electronic signal if the said remainder of said subtracter means is zero or negative;

a switching toggle means in electronic communication with said logic means and with said air control means, said switching means having an air increase state and an air decrease state, said switching means always beginning in said increase state which causes said air control to increase the amount of air input into said combustion device, said switching means being responsive to said logic means so that the state of said switching means is continued until a signal is received from said logic means which then switches the state of said switching means.

16. The device of claim 15 further comprising a dwell means which is adjustable to electronically set the amount of air increase or air decrease signal by said switching means.

17. A means for optimizing efficiency of a combustion device such as a furnace, boiler, oven, stove, and the like, wherein said fuel input and air input are variable to maintain a desired output level, comprising:

an output reading means operatively connected to said combustion device for monitoring the output of said combustion device;

an output reading transducer which converts the output reading of said output reading means into an electric signal;

a fuel control means in operative connection with a fuel input means which controls the amount of fuel input into said combustion device;

an output regulator means electronically connected to said output transducer means and said fuel control means, having an adjustable means for setting the desired output level and signalling said fuel control means to input sufficient fuel to maintain the set output level according to the readings of said output transducer;

a first electronic signal storage means in electronic communication with said fuel control means to store the present value of said fuel control means;

a second electronic signal storage means connected to said present electronic signal register means which stores the present fuel control reading and has a clock means attached thereto so that said second storage means stores the immediately preceding fuel control level to that of said first storage means to represent a change in fuel input to said combustion device;

a math unit subtracter means which subtracts said past reading from said present reading to represent a change in fuel input;

a logic means which is electronically connected to said subtracter means and which issues a signal if the fuel is raised or lowered;

a toggle switching means connected to said logic means and to an air control means, said switching means having an air lower state and an air higher state so that upon signalling from said logic unit, said toggle switches between the two states to raise or lower air input according to fuel input to maintain the optimum excess air level.