US2228769A - Combustion control - Google Patents

Description

Jan. 14, 1941. .J. J. KLINKER 2,228,769

COMBUSI ION CONTROL Filed April 21, 1937 7 wuc/rvfm JOHN J. KLl/YK ER.

Patented Jan. 14, 1941 UNITED STATES 2,228,769 COMBUSTION CONTROL John J. Klinker, Decatur, Ill., assignor to A. W. Cash Company, Decatur, 111., a corporation of Delaware Application April 21, 1937, Serial No. 138,211

2 Claims.

This invention relates to combustion control, and more particularly to the control of furnaces arranged to burn oil and utilizing an auxiliary fluid, such as air or steam, to atomize the oil.

In furnaces of this type the oil is supplied to the burners at a pressure which is varied with the demand for heat, and it has been found desirable to vary also the pressure of the atomizing fluid. However, the range of variation of the atomizing fluid pressure should in most cases be different from the range of variation of the oil pressure, and for the best operating results these ranges will depend upon the characteristics of the oil and various other conditions encountered in the particular installation. The problem is further complicated by the fact that in most of these 4 furnaces a plurality of burners are utilized, and

the number of burners in operation may be varied from time to time. While many different arrangements of apparatus have been proposed heretofore to control the supplies of oil and atomizing fluid, these prior arrangements have been in general incapable of the adjustments necessary to adapt them tothe operating conditions encountered in actual service.

It is accordingly one object of the invention to provide a comparatively simple and inexpensive apparatus for controlling combustion in a furnace arranged to burn oil and utilizing an auxiliary fluid to atomize the oil.

It is a further object of the invention to provide apparatus which will make possible simple and independent adjustments of the ranges of variationof the oil and of the atomizing fluid.

It is a further object of the invention to provide apparatus which will control the supply of oil in accordance with the demand for heat, while maintaining the correct proportions between the supplies of oil and atomizing fluid at all loads, and which will also control the supply of air to ensure eflicient combustion.

With these and other objects in view, as will be apparent to those skilled in the art, the invention resides inthe combination of parts set forth in the specification and covered by the claims appended hereto.

In accordance with my invention in its preferred form, I control the supplies of oil and of atomizing fluid by means of separate valves, each of which is actuated by a separate fluid-pressure responsive device. Each device is subjected to the fluid pressure at the discharge side of the valve and tends to close the valve upon an increase in this pressure. These devices are alsosubjected to independently controlled loading pressures which tend to open the 'valves, and for this purpose I preferably cause fluid to flow in a pair of conduits, each of which is provided with two adjustable restrictions or valves, and utilize the pressures between the restrictions in the respective conduits as loading pressures. One of the restrictions in each conduit may be adjusted in accordance with the demand for heat by means of a suitable regulator, and this same regulator may control the supply of air for combustion.

Referring to the drawing illustrating one embodiment of the invention, and in which like reference numerals indicate like parts, the single figure is a diagrammatic elevation of a steam boiler furnace and associated combustion control apparatus,' certain parts being shown in section for clearness of illustration.

The embodiment illustrated comprises a furnace Ill arranged to form a combustion chamber II, and a steam boiler l2 associated therewith. The boiler is provided with banks of water tubes l4 and a baflie l5 of usual construction, this baflie serving to direct the hot gases from the combustion chamber into proper contact with the water tubes and thence toa gas outlet duct l6, which may lead to a suitable stack or induced draft fan (not shown). Theoutlet duct I6 is provided with a damper l8 having an operating arm IS. The boiler i2 is provided with the usual steam delivery pipe 20.

On the front of the furnace mounted two oil burners 22 of the type utilizing an auxiliary fluid to atomize the oil. These burners are arranged to discharge the atomized oil rearwardly into the combustion chamber through openings 23 in the furnace wall. Air for combustion enters the combustion chamber through these openings at a rate controlled by the damper l8.

Fuel oil is supplied under pressure from any suitable source through a pipe 25 having branches 26 which lead to the burners 22. Each branch 26 is shown provided with a valve 21 which is normally open but which can be closed when it is desired to shut down the burner. The pipe 25 I 0 there areis provided with an automatic pressure reducing pression spring 34 which can be adjusted by means of a screw 35 at its upper end.

The fuel oil is atomized at the burners by a suitable atomizing fluid under pressure, and for this purpose I may use steam from the boiler I2. As shown in the drawing, steam may be withdrawn from the. steam delivery pipe 20 through a pipe 31 having branches 38 which lead to the burners 22. These branches 38 are provided with valves 39 which may be closed to shut down the burners but which are left fully open when the burners are in operation. The pipe 31 is provided with an automatic pressure reducing and regulating valve 4| similar to the valve 29 and comprising a valve member 42 connected by a bell crank lever 43 to a fluid-pressure responsive device in the form of a flexible diaphragm 45. This diaphragm is subjected on its lower surface to the steam pressure at the delivery side of the valve and it is urged downwardly in opposition to this pressure by means of a coiled compression spring 46 which can be adjusted by means of a screw 41 at its upper end.

With the construction as so far described, the automatic valves 29 and 4| will maintain the pressure of the oil and the steam at the burners substantially constant, these pressures depending upon the adjustment of the springs 34 and 46. It is desirable however to vary these pressures in acordance with the demand for heat, and for this purpose I provide means for varying the loading of the diaphragms 33 and 45. This is preferably accomplished by employing variable fluid pressures which may be applied directly to the upper surfaces of the diaphragms.

The preferred construction illustrated for pro- .viding these variable pressures comprises a pipe or conduit 49 having an inlet valve 50 and an outlet valve 5|, and a pipe or conduit 53 having an inlet valve 54 and an outlet valve 55. A suitable fluid, such as oil, is withdrawn from a tank 51 by means of a pump 59 and delivered under pressure through a pipe 59 to the inlet valves 50 and 54. A by-pass 6| leads from the pipe 59 back to the tank 51, this by-pass having a relief valve 62 therein. One suitable construction for this relief valve is disclosed in the patent to Terry No. 1,863,015. The outlet valves 5| and 55 are connected to an exhaust pipe 63 through which the oil is returned from the pipes 49 and 53 to the tank 51. The pressure in the pipe 49 is transmitted through a pipe 65 to the upper side of the diaphragm 33, and the pressure in the pipe 53 is transmitted through a pipe 66 to the upper side of the diaphragm 45. The outlet valves 5| and 55 are arranged for manual adjustment, whereas the inlet valves 50 and 54 are provided with operating levers 68 and 69 respectively which are connected by a link 10 and arranged to be actuated in accordance with the demand for heat by means of an automatic regulator 12. This regulator as illustrated is of the type disclosed in the patent to Temple No. 2,049,549, and comprises a diaphragm chamber 13 connected by a pipe 14 with the boiler steam pipe 20, and a motor 15 connected by a rod 16 with the valve lever 69. With this construction changes in the demand for heat will affect the steam pressure transmitted through the pipe 14 and cause the regulator 12 to adjust the inlet valves 58 and 54. This will change the rate of flow in the pipes 49 and 53, varying 'the loading pressures transmitted through the pipes 65 and 66, and causing the valves 29 and 4| to change the pressures of the fuel oil and steam supplied to the burners.

The supply of air for combustion is also controlled automatically, and for this purpose there is shown a regulator 18 of the type disclosed in the patent to Temple No. 1,992,048. This regulator comprises a pilot -valve mechanism 19 supplied with fluid under pressure from any suitablo source by a pipe 88 and connected by tubes 82, 82 to a hydraulic motor 83 which is connected to the damper operating arm IS. The pilot valve mechanism is actuated by a lever 85 and a flexible diaphragm 86, the diaphragm being loaded by means of a coiled tension spring 81. The upper end of the spring is supported by a nut 69 mounted on a vertical screw which can be raised and lowered by means of a lever 9|. This lever 9| is connected by a rod 93 to the valve lever 68. The pressure in the combustion chamber II is transmitted to the upper side of the diaphragm 88 by means of a pipe 94, and the pressure in the gas outlet duct I6 is transmitted to the lower side of the diaphragm by means of a pipe 95. The diaphragm 86 is thus subjected to an effective fluid pressure which is a function of the rate of flow of gases past the boiler l2 and the rate of flow of air into the combustion chamber. Hence the regulator 18 will control the damper l8 and maintain a predetermined rate of air flow corresponding to the loading afforded by the spring 81. This loading is controlled automatically by the regulator 12 and it can be adjusted manually by turning the screw 90.

The operation of the invention will now be apparent from the above disclosure. The pump 58 will supply oil to the pipe 59 at a substantially constant pressure as determined by the relief valve 62, and this oil will flow in part through the pipe 49 and in part through the pipe 53, eventually returning to the tank 51. With a steady demand for steam, the boiler |2 will deliver steam.

at a constant pressure, and the regulator 12 will remain stationary, holding the valves 50 and 54 partially open. If the various parts are properly adjusted, the pressure of the atomizing steam delivered to the burners by the valve 4| will be correctly proportioned to the pressure of the fuel oil delivered to the burners by the valve 29, and the air will enter the combustion chamber II at the correct rate in proportion to the rate of fuel supply. If now the demand for steam increases, the pressure in the pipe 20 will decrease slightly and the regulator 12 will move the valve levers 68 and 69 slightly downward, opening the valves 50 and 54 still further. This will increase the loading pressures transmitted through the pipes 65 and 66, causing the valves 29 and 4| to deliver fuel oil and steam for atomization at slightly higher pressures. The downward movement of the valve lever 68 will lower the rod 93 and rock the lever 9| to increase the tension of the spring 81. This will cause the diaphragm 86 to rise slightly, actuating the pilot valve mechanism 19, and causing the motor 83 to open the damper I8 until the rate of air flow into the furnace has increased sufiiciently to restore the diaphragm to its original position by the increased pressure differential transmitted through the pipes 94 and 95. Similarly, a decrease in the steam demand will cause the regulator 12 to close the valves 50 and 54 slightly, decreasing the loading pressures transmitted to the valves 29 and 4|, and causing these valves to decrease the pressures of the fuel oil and the steam for atomization. At the same time, the regulator 12 will decrease the tension of the spring 81, causing the regulator 18 to close the damper l8 slightly and decrease the flow of air into the furnace. One of the burners 22 can be shut down by closing the corresponding valves 21 and 39 without materially afiecting the oil or steam pressures at the other burner.

By means of the screws 35 and 41 it is possible to adjust the springs 34 and 46, and by adjusting the valves and 55 it is possible to vary the loading pressures transmitted through the pipes 65 and 66. In this way a wide adjustment of the pressures of the fuel oil and the atomlzing fluid is obtainable. For example, if the spring 34 is adjusted to give a fuel oil pressure of flve pounds at the burners with zero pressure in the pipe 65, and the valve 5! is adjusted to give a loading pressure in the pipe 65 varying from zero at minimum demand to twenty pounds at maximum demand, it will be apparent that throughout the operating range the fuel oil pressure at the burners will vary between five pounds and twenty-five pounds. Similarly, if the spring 46 is arhusted to give an atomizing fluid pressure of fifty pounds at the burners with zero pressure in the pipe 66, and the valve 55 is adjusted to give a loading pressure in the pipe 66 varying from zero at, minimum demand to fifty pounds. at maximum demand, it will be apparent that throughout the operating range the atomizing fluid pressure at the burners will vary between fifty and one hundred pounds. that these various adjustments make it possible to adapt the system readily to various types .of burners and to difierent fuels and operating conditions.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

It will be clear 1. Control apparatus for a furnace arranged to be fired by an oil burner, comprising a valve to control the flow of oil to the burner, a valve to control the flow of atomizing fluid to the burner, a pair of conduits, means providing two adjustable restrictions in each conduit, means to supply loading fluid to both conduits, actuating means for the first valve responsive both to the loading fluid pressure between the restrictions in one conduit and to the pressure of the oil delivered by the valve, actuating means for the second valve responsive both to the loading fluid pressure between the restrictions in the other conduit and to the pressure of the atomizing fluid delivered by the valve, a regulator arranged to adjust one of said restrictions in each conduit in accordance with the demand for heat, and means controlled by said regulator to control the flow of air into the furnace for combustion.

2. Control apparatus for a furnace arranged to be fired by an oil burner, comprising a valve to control the flow of oil to the burner, a valve to control the flow of atomizing fluid to the burner, a pair of conduits, two valves in each conduit, means to supply loading fluid to both conduits, actuating means for the first mentioned valve responsiveboth to the loading fluid pressure between the valves in one conduit and to the pressure of the oil delivered by the first mentioned valve, actuating means for the second mentioned valve responsive both to the loading fluid pressure between the valves in the other conduit and to the pressure of the atomizing fluid delivered by thesecond mentioned valve, a regulator responsive to changes in the demand for heat, and

means connecting said regulator to one of the valves in each of said conduits to actuate the same.-

JOHN J. KLINKER.

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