US2178672A - Fluid burner controller - Google Patents

Description

L jag W N m T T A ii nf' Ml my M M a M P U A L III,

Nov. 7, 1939. M. PERKINS FLUID BURNER CONTROLLER Filed Aug. 11, 1957 Patented Nov. 7, 1939 FLUID BURNER CONTROLLER Laurence M. Perkins, Syracuse, N. Y., assignor to Carrier Corporation, Newark, N. J., a corporation of Delaware Application August 11, 1937, Serial No. 158,460

11 Claims.

This invention relates to combustion devices such as oil burners and more particularly to an improved method of and apparatus for controlling the operation thereof.

When oil or any other fuel is burned, it is essential, if greatest operating efficiency is to be Obtained, that a minimum of excess air be supplied for combustion. This follows from the fact that the excess air supplied does not enter into chemical combustion with the fuel and therefore does not foster the liberation of heat, but serves merely to carry away heat units from the combustion chamber, to increase the stack loss, and thus to detract from the efficiency of the burner device. On the other hand, if an insuflicient quantity of air is supplied, the oil or other fuel will not be completely burned and some of it will be deposited as soot While another portion of the fuel may escape up the chimney without 20 having been burned. This operating condition also results in inefliciency.

When the flame of an oil burner is first started, the chimney is cold. Thus, there is relatively little draft with the result that less air is supplied to the combustion chamber than after the chimney has become heated and the draft increased thereby, Also, when oil is cold, as it usually is prior to the operation of an oil burner, it has a higher viscosity than when it is warm. The spray nozzles which are commonly used with pressure type oil burnersare so constructed as to deliver a larger quantity of oil at a given pressure when the oil has a high viscosity than when the oil has a lower viscosity. Accordingly, when an oil burner is started, both the relatively low draft and the relatively high oil viscosity tend to decrease the ratio of air to oil, and thus tend to cause soot deposit and incomplete combustion of the fuel. To provide efficient operation, therefore, it is necessary to vary this ratio so that the oil and air are in desired proportions at all times. This may be accomplished by reducing the amount of oil supplied to the burner during starting-up periods.

After the oil burner has been operating for a short time, the chimney has become heated, the draft increased, and hence there is a greater supply of air to the combustion chamber. Then oil may be supplied to the combustion chamber at a greater rate than during the starting-up period.

When it is realized that in conventional applications oil burners frequently go on and off several times an hour throughout the day, or 55 even. more frequently, there will become apparent the importance of providing for eificient combustion during both normal operating and starting-up periods, and of preventing the deposit of soot.

The object of this invention is to provide for the supply to the combustion" chamber of a fluid burner device of fuel and air in desired proportions both during starting-up periods and during periods of normal operation, to insure high operating eiliciency and to prevent soot deposit.

Another object of the invention is to provide a method of and apparatus for supplying fluid fuel to a burner at a relatively low rate during starting-up periods and at a greater rate during periods of normal operation following the starting-up periods.

It is another object of the invention to provide a fuel control device for fluid burning devices such as oil burners, which is adapted automatically to provide for optimum conditions of combustion during all periods of operation, whereby the operating efliciency of the device may be increased, the cost of operation minimized, and the cost of maintenance substantially reduced.

According to present practice, it is customary in supplying oil to the nozzle of an oil burner device to pump a considerable quantity of oil from an oil supply tank. This oil is supplied to a pressure regulating valve which is designed to maintain a substantially constant predetermined pressure within the pipe leading to the nozzle whenever the oil burner is operative, and to positively close the oil passage leading to the nozzle whenever the oil burner becomes inoperative. Of the total volume of oil supplied to the pressure regulating valve, a relatively small portion only is supplied to the nozzle, the remainder of the oil being circulated throughrthe pressure regulating valve and then returned through a bypass line to the oil supply tank.

According to the invention, there is provided a valve in the bypass line of the arrangement just described for restricting the flow of fuel through the bypass line.

When the valve in the bypass line restricts fiow therethrough to a relatively great extent, pressure is developed in the fluid circulating system back of the valve. This increase in pressure, transmitted through the pressure regulating valve, affects the pressure in the pipe leading to the nozzle, and as the pressure in this pipe is increased, the rate at which fluid is discharged therefrom increases. When the valve in the bypass line restricts flow therethrough to a lesser extent, the pressure within the fluid circulating system is less than in the case of greater restriction of the bypass line. Accordingly, in such case, the fluid pressure in the circulating system back of the valve and in the pipe leading to the nozzle is lower and fluid is discharged from the nozzle at a lower rate.

Accordingly, a feature of the invention resides in providing flow control means, such as a valve, for variably restricting fluid flow through a bypass line through which fluid is returned from the pressure regulating valve of an oil burner oil circulating system to the oil tank thereof.

Other objects, features and advantages of the invention will be more apparent from the following description to be read in connection with the accompanying drawing, 'in which:

Fig. l diagrammatically represents an oil bumer system embodying the invention, and

Fig. 2 diagrammatically represents an oil burn-- er system embodying a modifled form of the in -q ventlon.

Referring now to the drawing, the numeral ll designates an electrical motor driving a Ian M adapted to discharge air through casing I2 into a combustion chamber generally designated l2. Motor l2, through ,a drive chain H or other suitable means, is adapted to drive oil pump II which draws oil from oil supply tank It through line H and supplies it through line l8 to a pressure regulating device generally designated I8. 011 supply line 28 supplies oil from pressure regulating device l8 to oil discharge nozzle 2| located within the path of air discharged from casing I2. 22 designates a spark device for igniting oil discharged irom nozzle 2|. Spark device 22 may be of any desired type or construction and may be connected to a suitable source of electrical energy in any desired manner, and since the construction and operation of such devices are well known in the art, no further description of device 22 is deemed necessary here.

Connecting with the pressure regulating device I8 is a bypass line generally designated 22, adapted to retm'n oil irom the pressure regulating device to the oil supply tank l8. Interposed in the line 22 is an auxiliary valve generally designated 24. For convenience, that portion oi. line 22 which lies between the valves. l8 and 24 is designated 22a and that portion of the line 22 which lies between the valve 24 and tank I8 is designated 22b. Pressure regulating device I8 is provided with a partition 25 which is i'ormed with an opening 25 and an auxiliary opening 21. Extending through opening 28 is a double ended valve member of the needle valve type designated 28. One end 01' member 28 is adapted to control the supply oi fluid to line 28 through port 28 formed at an end of the pressure-regulating device. A spring 28 operating against a flange 2| formed on valve member 28 tends to force the valve member 28 away from port 28.

lhe oppositeend of valve member 28, which ex- 7 tends through opening 26, is adapted to control fluid flow through a port 22 formed in plate 22. Plate 22 is carried upon bellows 24, the bellows being secured to the inside of pressure regulating device l8. A spring 25 tends to force plate 22 toward partition 25. Preferably, a screw regulating device 25, extending through the casing of the pressure regulating device, is provided to control the pressure exerted by spring 25 on the plate 22. The pressure oi spring 25 is greater than that or spring 28. Thus, when the system is inoperative, as during shut-down periodswhen the oil pump I is not operative, spring 25 will force the plate 22 against member 28 and force member 28 to close port 22.

Valve 24 includes a valve chamber 21 within which is, disposed a valve member 28 carried upon and actuated by a sylphon bellows 28 attached-to the valve casing. The interior of bellows 28 is connected through line 48 with a thermal element 4|. Thermal element 4| is adapted to be heated by an electrical heating coil 42 which is adapted to be energized whenever the motor I8 is energized, i. e., whenever the burner device is operative. The heating coil 42 may be connected in series with the motor |8 or in parallel therewith, as shown. The switch means controlling the energization of the electrical circuits,

ably controlled responsive to variations in the temperature of a room or the like heated by the device, by means of a suitable thermostatic control. Since such control is old and familiar in the art, no further description of this feature is deemed necessary here.

In operation, the tan H and the pump I5 are rendered operative by the energization of motor I8, fan N then discharging air through casing V I2 into combustion chamber l2. Oil pump |5 draws oil from supply tank l5 and delivers it through line |8 to the pressure regulating device I8. The oil passes through opening 21 and thus builds up a pressure within the chamber 42 which forces the plate 22 backward against the pressure of spring 25. As the plate 22 moves to the right, the valve member 28 follows the plate under the influence of spring 28 and thus provides communication between the chamber 44 and the oil supply line 28 through port 28, whereby oil is delivered to the nozzle 2 I. The motion of valve member 28 to the right is limited by a collar 45 adapted to engage partition 25. As the oil pressure in chambers 44 and 42 continues to build up, the port 28 continues to supply oil to the nozzle 2|; and the plate 22 is pushed away from the right-hand end of valve member 28 when the oil pressure is sufllcient to overcome pressure or spring 25. Thus port 22 is opened, whereupon oil flows from chamber 42 through the interior oi the bellows 24 and thence through line 22. All of these operations take place within a second or two after the oil pump begins to operate.

Since the heating coil 42 at this time is relatively cold, due to the fact that the oil burner has been inoperative and the operating period has Just commenced, the fluid within the thermal element 4|, the line 48 and bellows 28 is in relatively contracted condition. Thus, the valve member 28 is, at the commencement of an operating period, in such position as to restrict to a relatively slight degree only oil flow through line 22.

However, as the oil burner continues in operation, the energization of the heating coil 42 contlnues to heat the fluid within the thermal element 4| and the bellows 28 is accordingly expanded. Thus, the valve member 28 is caused increasingly to restrict oil flow through the line 22. As will be understood, the restricting eflect of valve 28 causes a pressure to be built up in valve chamber 2'| and in line 220. This pressure is transmitted in turn to the interior of bellows 24 and through port 22 into chamber 44 and thus to the oil supply line 28. The increased oil pressure in line 28 results, in turn, in increased delivery of oil from the supply nozzle. In this way the pressure in the oil supply line 28 'is controlled by variations of pressure in line.22.

As will be understood, the restrictive action of valve 38 increases as the pressure within the bellows 39 builds up, or in other words, as the oil burner device continues in operation. Thus, the oil pressure in the oil supply line 20 begins to increase immediately following the time when the oil burner becomes operative. The pressure in bellows 39 stops rising when, after a time, the heat dissipated from the thermal element equals the heat input thereto, following which the pressure in chamber 31 and in line 23a remains substantially constant. Accordingly, the

pressure in chamber 44 and in supply line 2|! also reaches a corresponding maximum point, at which the pressure remains constant throughout the remainder of the operating period.

When the oil burner is rendered inoperative, the heating coil 42 is deenergized and valve member 38 is gradually moved away from its seat. Also valve member 28 closes port 29 under the influence of spring 35. Thus the apparatus is adapted to operate as above described upon the commencement of the next operating period.

In Fig. 2, the heating coil 42 is dispensed with and the thermal element 4| is located within the combustion chamber I3. Thus, as the oil burner continues to operate, the fluid in thermal element as continues to be heated, whereby desired control of the oil supply is effected substantially as described in connection with Fig. 1. It will be understood that the thermal element need not be placed within the combustion chamber, but may be located at any desired point where it is heated by operation of. the burner, as, for example, in the stack.

Thus, it will be seen that during the period during which the oil burner is beginning to operate the oil pressure in the oil supply line is relatively low, and hence there is a relatively small quantity of oil delivered therefrom. But as the burner continues to operate, the pressure in the oil supply line leading to the discharge nozzle (and hence the rate of oil discharge from the nozzle) is increased, until it reaches a predetermined and constant maximum value, the oil pressure remaining at this point until the operation of the oil' burner is interrupted.

As will be understood, the pressure in chamber 44, and hence the pressure in line 20, is determined in accordance with pressure differential across plate 33, and this pressure differential is directly controlled by the pressure exerted by the spring 35. It will be seen, therefore, that the pressure in the oil supply line 20 may be regulated by adjustment of regulating device 36, which controls the pressure exerted by spring 35.

Since many modifications may be made in the invention without departing from the scope thereof, it is to be understood that the foregoing description and accompanying drawing are intended as illustrative only, applicant limiting himself only as indicated in the appended claims.

I claim:

1. In a fluid burner device adapted to be intermittently operative, a source of fluid fuel, a burner, a pressure regulating valve serving said burner at all times during operation of the latter, means for supplying fuel from said source to said valve, means constantly supplying to said burner from said valve a. portion only of. the fuel supplied to said valve, means constantly returning to said source of fuel from said valve another portion of the fuel supplied to said valve, auxiliary valve means for controlling said return of fuel to said source and for controlling the pressure at which fuel is supplied to said burner from said first-mentioned valve, a thermal element, means for heating said thermal element responsive to operation of the device, and means responsive to heating of said thermal element for decreasing to a predetermined point the effective opening of said auxiliary valve means.

2. In a fluid burner device adapted to be intermittently operative, a source of fluid fuel, a burner, a pressure regulating valve serving said burner at all times during the operation of the latter, means for supplying fuel from said source to said valve, means constantly supplying to said burner from said valve a portion only of the fuel supplied to said valve, means constantly returning to said source of fuel from'said valve another portion of the fuel supplied to said valve, auxil iary valve means for controlling said return of fuel to said source and for controlling the pressure at which fuel is supplied to said burner from said first-mentioned valve, a thermal element, means for heating said thermal element responsive to operation of the device, and means responsive to heating of said thermal element for restricting flow through said auxiliary valve means subsequent to the commencement of a burner operating period so that fuel is thereafter supplied to said burner from said pressure regulating valve at a predetermined pressure.

3. In a fluid burner device adapted to be intermittently operative, a source of fluid fuel, a burner, a pressure regulating valve controlling the supply of fuel to said burner at all times during the operation of the latter, means for supplying fuel from said source to said valve, means constantly supplying to said burner from said valve a portion only of the fuel supplied to said valve, means constantly returning to said source of fuel from said valve another portion of the fuel supplied to said valve, auxiliary valve means for controlling said return of fuel to said source and for controlling the pressure at which fuel is supplied to said burner from said first-mentioned valve, 8. thermal element, a heating coil adapted to heat said thermal element, means for rendering operative said heating coil whenever said device is operative, and means responsive to heating of said thermal element for restricting flow through said auxiliary valve means.

4. In a fluid burner device adapted to be intermittently operative, a source of fluid fuel, a burner, a pressure regulating valve controlling the supply of fuel to said burner at all times during the operation of. the latter, means for supplying fuel from said source to said valve, means constantly supplying to said burner from said valve a portion only of the fuel supplied to said valve, means constantly returning to said source of fuel from said valve another portion of the fuel supplied to said valve, auxiliary valve means for controlling said return of fuel to said source and for controlling the pressure at which fuel is supplied to said burner from said first-mentioned valve, a thermal element adapted to be heated by combustion of fuel within the device, and means responsive to heating of said thermal element for restricting flow through said auxiliary valve means.

5. In combination with a fluid burner device including a source of fuel, a burner, a pressure regulating valve serving said burner and controlling the supply of fuel thereto at all times during the operation of said burner, means for supplying fuel from said source to said pressure regulating valve, means constantly supplying to said burner a portion only of the oil supplied to said valve, and means constantly returningto said source the remaining portion of oil supplied. to said valve; auxiliary valve means for restricting the flow of fuel from said valve to said source and for regulating the pressure at which fuel is supplied from said valve to said burner, means for operating said valve, and means for controlling said operating means responsive to operation of the device, said control means and said operating means being adapted and arranged to restrict fluid flow through said auxiliary valve means following the commencement of a burner operating period, whereby to increase the pressure at which fuel is supplied to said burner to a predetermined point, said control means and said operating means being adapted and arranged thereafter, during the remainder of the operating period, to maintain such restriction of said auxiliary valve means to maintain said fuel pressure at said predetermined point.

6. In a fluid burner device adapted to be intermittently operative, a source of fluid fuel, a burner, a pressure regulating valve serving said burner and controlling the supply of fuel thereto at all times during the operation of said burner, means for supplying fuel from said source to said valve, means constantly supplying to said burner from said valve a portion only of the fuel supplied to said valve, means constantly returning to said source of fuel from said valve another portion of the fuel supplied to said valve, auxiliary valve means for controlling said return of fuel to said source and for controlling the pressure at which fuel is supplied to said burner from said firstmentioned valve, a pressure-responsive element, means for actuating said pressure-responsive element responsive to operation of the device, and means responsive to actuation of said pressure-responsive element for restricting fluid flow through said auxiliary valve means.

7. In an apparatus of the character described, a source of fluid fuel, a burner, a pressure regulating valve serving said burner at all times during operation of the latter, means for supplying fuel from said source to said valve, means constantly supplying to said burner from said valve a portion only of the fuel supplied to said valve, means constantly returning to said source from said valve another portion only of the fuel supplied to said valve, auxiliary valve means for controlling said return of fuel to said source and adapted to control the pressure at which fuel is supplied to said burner from said first-mentioned valve, and means for restricting fuel flow through said auxiliary valve means to a predetermined limit following initiation of a burner operating period.

8. In a fluid burner device adapted to be intermittently operative, a source of fluid fuel, a burner, a pressure regulating valve serving said burner at all times during operation of the latter, means for supplying fuel from said source to said valve, means constantly supplying to said burner from said valve a portion only of the fuel supplied to said valve, means constantly returning to said source of fuel from said valve another portion only of the fuel supplied to said valve, auxiliary valve means for controlling the return to said source of said other portion of the fuel and adapted to control the pressure at which fuel is supplied to said burner from said first-mentioned valve, and means for causing said auxiliary valve means to restrict, to a predetermined limit, the flow of ,fuel being returned to said source responsive to the lapse of time subsequent to the commencement of a burner operating period.

9. In a fluid burner device adapted to be intermittently operative, a source of fluidfuel, a bumer, a pressure regulating valve mechanism includinga first valve and a second valve, said mechanism serving said burner at all times during operation of the latter, means for supplying fuel from said source to said valve mechanism, means including said flrst valve constantly supplying to said burner from said valve mechanism a portion only of the fuel supplied to said valve mechanism, means including said second valve constantLv returning to said source of fuel from said valve mechanism another portion only of the fuel supplied to said valve mechanism, auxiliary valve means for controlling said'return of fuel to said source and adapted to control the pressure at which. fuel is supplied to said burner from said valve mechanism, and means responsive tooontinuedoperation of the burner for causing said auxiliary valve means to restrict the flow of fuel returning to said source to a predetermined limit following the initiation of a burner operating period.

10. In a fluid burner device adapted to be intermittently operative, a source of fluid fuel, a burner, a pressure regulating valve controlling the supply of. fuel to said burner and serving said burner at all times during the operation of said burner, means for supplying fluid fuel from said source to said valve, means at all times during the operation of said burner supplying to said burner from said valve a portion only of the fuel supplied to said valve, means at all times during the operation of said burner returning to said source from said valve another portion of the fuel supplied to said valve, means for controlling the return to said source of said lastmentioned portion of the fuel and adapted to control the pressure at which fuel is supplied to said burner from said valve, and means for causing said control means to restrict the flow of fuel returning to said source responsive to continued operation of the burner subsequent to the commencement of a burner operating period.

11. In an apparatus of the character described, a source of fluid fuel, a burner, a pressure regulating valve mechanism serving said burner at all times during operation of the latter, means supplying fuel from said source to said valve mech'anism, means constantly throughout a burner operating period supplying to said burner from said valve mechanism a portion only of the fuel supplied to said valve mechanism, means constantly throughout a burner operating period returning to said source from said valve mechanism another portion only of the fuel supplied to said valvemechanism, auxiliary means for controlling said return of. fuel to said source and adapted to control the pressure at which fuel is supplied to said burner from said valve mechanism, and means in control of said last-mentioned auxiliary means for restricting to a predetermined limit, following initiation of a burner operating period, the return of fuel from said valve mechanism to said source of fuel.

LAURENCE M. PERKINS.

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