Electronic combustion control system
AssigneeCMI Corporation
InventorsStuart W. Murray, Kenneth D. Cosby
Life of this patent
Estimating the term…
Abstract
An apparatus and method for adjusting the air-fuel ratio of a burner in order to minimize the presence of undesirable emissions in exhaust gases of the burner combustion. A burner calibration is performed by selecting a number of calibration points corresponding to burner fuel positions. Air flow is varied for each calibration point as an exhaust gas analyzer determines the content of exhaust gases of the burner combustion. Air settings for optimal combustion are determined for each calibration point and are stored in a programmable logic controller and software. During plant operation, the programmable logic controller and software adjust the air supplied to the combustion of the burner according to the calibration data and the fuel position of the burner.
Claims9
A method of achieving improved combustion in a hot mix asphalt plant having a drum, a burner and adjustable air flow to combustion of the burner, the steps of the method comprising:
- (a) calibrating the burner, the steps of calibrating the burner comprising:
- (1) selecting a plurality of fuel positions for the burner;
- (2) inserting an exhaust gas analyzer probe into the drum proximate to combustion of the burner, the exhaust gas analyzer probe being connected to an exhaust gas analyzer to provide an analysis of the constituents of the combustion products of the burner;
- (3) varying the air flow to the combustion of the burner for a plurality of air settings at each fuel position of the burner;
- and
- (4) determining an optimal air setting for each fuel position of the burner by comparing the analysis of the constituents of the combustion products for each air setting for each fuel position;
- and
- (b) controlling the air flow to the combustion of the burner during operation of the plant to produce asphalt, the steps of controlling air flow comprising:
- (1) monitoring the fuel position of the burner for changes in the selected fuel position;
- and
- (2) adjusting the air flow to the combustion of the burner to the optimal air setting for the selected fuel position of the burner in response to the changes in the selected fuel position.
In a hot mix asphalt production plant, the combination comprising:
- a drum;
- burner means attached to the drum and having combustion for drying aggregate moving through the drum, the burner means including a fuel line for providing a supply of fuel to the burner means;
- a fuel control valve installed in the fuel line to adjust the supply of fuel to the combustion of the burner means, the fuel control valve having a plurality of fuel positions, each fuel position corresponding to a preselected amount of fuel being supplied to the burner means;
- blower means, attached to the drum, for providing a supply of air to the combustion of the burner means;
- air control means, attached to the blower means and having a plurality of predetermined air settings, for adjusting the supply of air to the combustion of the burner means, each air setting corresponding to a predefined amount of air being supplied into the drum;
- and
- an exhaust system attached to the drum and receiving products of combustion produced by the burner means;
- electronic means, connected to the fuel control valve and the air control means and being programmed with a predetermined optimal air setting corresponding to each fuel position, for causing the air control means to assume the corresponding optimal air setting whenever the fuel control valve is changed to another one of the fuel positions.
Dependencies are inferred from the claim text.