US2390806A

US2390806A - Oil burning system

Info

Publication number: US2390806A
Application number: US457933A
Authority: US
Inventors: Nagel Theodore
Original assignee: Individual
Current assignee: Individual
Priority date: 1942-09-11
Filing date: 1942-09-11
Publication date: 1945-12-11
Anticipated expiration: 1962-12-11

Description

Dec. 11, 1945. T. NAGEL OIL BURNING SYSTEM Filed Sept. 1-1, 1942 2 Sheets-Sheet 1 Ix l INVENTOR ATTORNEY Dec. 11, 1945. T. NAGEL 2,390,806

OIL BURNING SYSTEM- Filed Sept. 11, 1942 2 Sheets-Sheet 2 G. 360 E l 250- n; 9) L: Q 200 R REL/IT/VE VOLUMES OF OIL o I Patented Dec.-- ll, 1945 -UNITED STATES PATENT OFFICE I OIL BURNING SYSTEM Theodore Nagel, Brooklyn, N. Y.

Application September 11, 1942, Serial No. 457,933

"6 Claims. (c1. 15845.5)

This invention is directed to oil burning systems and has for one of its objects the provision of an oil buming system which, while it may be controlled manually or semi-automatically, is preferably controlled entirely automatically, wherein the practical maximum fuel range is very materially increased as compared with existing automatically controlled systems.

In marine service, for example, the fuel range requirements for ships at sea approximate 8 to 1. Prior to 'my invention the practical maximum fuel range of oil burning systems for marine service at sea, where oil pressure and flow are varied under automatic combustion control, is about 2 to 1. In oil burning systems with constant pressure, variable capacity oil burners, having oil recirculation systems with automatic combustion control, the practical maximum fuel range-approximates 5 to 1. For the wider fuel range demand in marine service at sea, the two systems above referred to require the manual turning off and relighting of burners.

At a meeting of naval architects, ship builders and equipment manufacturers on the subject of Combustion controls in marine service" sponsored by the American Society of Mechanical Engineers, and held in the society's building at 29 West 39th Street, New York city, on March 20, 1942, the chief engineer of the Federal Shipbuilding and Drydock Corporation pointed out that the practical operating range of conventional oil burning systems equipped with automatic comand air are injected. These nozzles are so arranged and controlled that one nozzle will continuously deliver 011 and remain lighted so long as the furnace is in service, and function as a torch for lighting the other nozzles as they are placed in service, the number of nozzles in service depending upon the steam demand on the boiler ment of my invention;

bustion control fell short of marine requirements,

as above pointed out, and stressed the need for increasing the range of complete automatic comout removing burners when they are turned off.

It is to be understood, of course, that my system may be manually controlled or it may be controlled semi-automatically, or as presently to be described and as preferred in marine service, it may be entirely automatically controlled.

I wish to emphasize also that my improved system is adapted for other than marine work,

the marine service having been mentioned purely by way of illustration as a certificate of need.

Broadly speaking, my invention provides an oil burning system wherein I place a multiple number of oil burner nozzles, constituting a nest, at each furnace firing entrance, through which fuel opening 4 of a furnace. In Fig. 1 these nozzles, I

for clarity of description, are designated 1, II, III, IV and V. These nozzles are so disposed relatively to each other and to thefurnace firing opening that the spread of the diverging stream of ignited atomized oil from each nozzle approximates the diameter of the firing opening so that on of the nozzles, which is always burning so long as the furnace is in service, will function as a torch in lighting the other nozzles when steam demand requires that they be set in operation.

The nozzle nest is surrounded by a windshield 6, air for ignition passing to the nozzles through the wind-shielded zone thus provided, damper controlled torch-hole'openingt being provided for. initially lighting up. Combustion air is supplied at I0 about the exterior of the windshield 6. The method involved in the operation of the nozzles 2 is covered by my prior Patent No. 2,206,553, dated July 2, 1940.

This oil burning system is purely illustrative and other types may be used instead of the one illustrated.

I2 designates a steam main from the steam generating system and I I8 a master control connected to the steam main I2 by line I 20-. The pipe for supplying oil to the nozzles is designated I22. This line may feed any number of nozzle nests, as will be understood, although shown as feeding but the one nest.

I24 designates the oil pump motor and I26 the oil' pump for delivering oil under controlled variable pressure to the line I22 from any suitable supply source I28, the usual oil strainers and oil heaters not being shown.

The master control II8 controls an oil pressure regulating valve I 30 by which the oil pressure in the line I 22 is varied. The oil return line from the pressure regulating valve I30- to the supply tank is designated I32.

I34 designates switch mechanism which is controlledbythepressureoftheoilin theoilline I22. Nozzle I of the nozzle nest is manually controlled in that it is equipped with a manually controlled oil valve 3. The reason for this is that this nomle is always on oil so long as the equip-h ment is in service. Nozzles II. III, IV and V, however, are equipped with solenoid operated valves I36 which are controlled by the switch I34 as will be brought out hereinafter. Purge line 32 connected to the steam main I2 is provided for purging each nozzle of the nest as the nomles are shut oil.

34 designates a blower for supplying combustion air to the nomles. This blower is driven at variable speed depending upon the number of nozzlcs in operation at any instant. The switch for controlling the blower speed is the switch I34 above referred to. This switch also controls the setting of damper 36. 7

To produce efflcient combustion, approximately I25 pounds minimum oil pressure is required to effect good atomization of fuel oil, which must be preheated to increase its fluidity to approximately 150 seconds Saybolt Universal. Oil pressures substantially less than 125 pounds produce inefficient combustion primarily due to inefliclent atomization.

The relative capacity of the orifice of a pressure-atomizing nozzle varies directly as a funcwill lie-ignited by nozzle I, will beput in servi at 130 pounds oil pressure.

At this same time the movable contact I46 of the switch I34 will have been moved clockwise to engage fixed contact I46 to short circuit resistance I43 in the circuit of the motor for the blower v sure and each five pound increase in oil pressure until the oil pressure has been increased to 145 pounds and all five nozzles ar in operation.

Up to 145 pounds of oil Pressure the speed of the blower 34 increased on each five pounds rise in oil pressure in the line I22 thereby to supply sumcient combustion air to the nozzles withtion of the square root of the oil pressure, so that as the oil pressure range increases, the oil capacity curve increases its divergence from a straight line. Functioning over a limited oil pressure range with automatic combustion control, wherein the combustion air volumes approximate a straightline-increase in air volume with respect to a straight-line-increase in oil volume, is important for producing efllcient combustion. The deviation of oil nozzle capacity curve from a straight line is illustrated in Fig. 3, which also shows a limited oil pressure range wherein the curve of the nozzle-oil-capacity range approximates a straight line. This pressure range, as shown in Fig. 3, extends from 125 pounds to 350 pounds and for best results I operate within this oil pressure range.

In Fig. 1 I have shown all parts in the positions occupied when the equipment is simply runnin on nozzle I which means, of course, that the solenoid operated valves I36 for nozzles 11, III, IV and V are closed. The damper 36 too is in closed position, this position of the damper, however,

allowing air to how past the damper in'volu'me required for the operation of nozzle I with the blower 34 running at its slowest speed.

The pressure of the oil in the oil line I22 may be 125 POllDdS and the steam pressure in th main I2 255 pounds, for example. Upon the demand for more steam than is being generated by nozzle I there will be a drop in the pressure in the steam line I2 and the master control 6, which is connected directly to the steam line, functions to operate the pressure control valve I30 to increase the oil pressure in the line I22.

When this oil pressure has built up to 130 pounds, for example, during which time the steam pressure in the main I2 has dropped for example one pound, the movable contact I38 of the switch mechanism I34 will have been moved, due to the mentioned increase inoil pressure, this switch mechanism I34 being connected by the line I40 with the oil line I22, into position to engage fixed contact I42. This contact controls the circuit of the solenoid of the. valve I of nozzle 11 to open this valve and this nozzle, which out altering the setting of the damper 36. Should the demand for steam continue to increase so 7 as to exceedthe steam now being generated the resultant drop in pressure in the steam line will step with the increased demand for combustion air until at 325 pounds the damper stands fully the combustion air can be used should the blower be driven by steam instead of electricity simply by regulating the steam valve-on continued increase in steam demand.

All five nozzles are now in operation. The oil pressure in the line I22is 325 pounds, the damper 36 is fully open, the blower 34 is running at maximum speed and the pressure from the steam line I2 has dropped to'say 250 pounds. The system, therefore, is now operating at maximum capacity.

On a decrease in the steam demand the above described cycle is reversed, the nozzles being separately-shut oil in the order V, IV, III and II at 145, 140, 135 and 130 pounds oil pressure due to the successive opening of the circuits which close the oil valves I36. The air damper 36, it will be appreciated, gradually moves through to its initially closed position and the air blower 34 then gradually decreases in speed. The pressure in the steam line I2 gradually rises until with only nozzle I inoperation and the oil pressure at pounds the pressure in this line will have risen to its original pressure of 255 pounds.

As previously pointed out, the steam-line 32 from the steam main I2 is connected to each nozzle valve 32 and as each valve operates to shut off its oil flow it at the same time opens the line 32 to admit steam to the nozzle to purge the same of residual oil. When the equipment is entirely closed down, that is, when the hand valve 3 for the nomle I is closed, a connection is opened to the steam line 32 to purge this nozzle also.

It will be seen, therefore, from the foregoing that the system illustrated in Fig. 1 provides for automatically maintaining a steam pressure Similar methods to that described of control of asocaoe parting from the spirit and scope of my invention.

Fig. 3 as an example shows the relative capacities of each nozzle and nest of fuel nozzles at oil pressures varying over a range from 125 to 325 ounds per square inch as follows:

Relative capacities of single nozzle and nest of five nozzles Pounds oil pressure 6 4 on on on on 6 4 3.92 s on on s 4 3.92 see on on n s 4 s92 ass sec on I (torch). s 4 3.92 see 3.80 3.14

Relative capacityso 20 15.68 11.58 7.00 3.14 Capacity ratio... 8. 0 5. 35 4. 2 3. 1 2.0 1. 0

It will be seen from the foregoing that my invention provides for -a fuel range of 8 to l in this example.

The relative nozzle capacities in the above table can be used for determining exact oil capacities of the nozzles. Forfexample, a ship with two boilers burns 360 barrels per 24 hours (full speed) at sea. With one nest. of five nozzles for each boiler, the nozzle capacity per hour at 325 pounds oil pressure will be v 360 2X24X5 furnace firing openings, it is to be understood that there is a nest of nozzles at each furnace firin opening and that the nozzles are so disposed relatively that one nozzle of each nest will function as a torch for lighting the others.

It is to be understood also that while so far as an 8 to 1 fuel range is concerned, this or any other desired range can be obtained whether the nozzles are controlled manually, semi-automatically, or automatically. For my purpose full automatic control is preferred.

It is to be understood also that the various controlling devices herein described may be substituted by other types within the purview or my invention and that various other changes may be made in the details of construction and arrangement of parts herein illustrated and described without departing from the spirit and scope of my invention.

What I claim is:

However, whether an installation inciudes one or several furnaces and one or several 1. An oil burning system comprising a plurality or nest of oil burner nozzles at a firing opening of a furnace, an electrically operated oil valve for each of said nozzles, with one exception, oil pressure operated switch mechanism for controlling said valves, and an oil pressure valve controlled by th steam pressure generated by the furnace for controlling said switch mechanism,

2. An oil burning system comprising in combination a plurality or nest of oil burner nozzles at a firing opening of a furnace, a. blower for suplying combustion air to the nozzles, switch mechanism for varying the speed of said blower, thereby to vary the combustion air delivered by said blower, and a damper in the air stream connected to said switch mechanism, said damper opening after the switch mechanism for the blower has been actuated to maximum blower speed.

3. An oil burning system comprising a plurality or nest of pressure atomizing nozzles at a firing opening of a furnace, an oil line common to all of said nozzles for supplying oil under pressure to the nozzles, a pressure regulating valve in the said oil line controlled by the steam pressure generat ed by the furnace for varying the oil pressure in the line, an electrically operated valve for each of said nozzles, and a switch controlled by said pressure regulating valve for controlling said electrically operated valves to eifect the successive turning on and turning oif of some of said nozzles with variations in the steam pressure generated by the furnace.

4. An oil burning system comprising in combination a plurality or nest of pressure atomizlng nozzles at a firing opening-of a furnace, means for supplying oil under variable pressure to said nozzles, an electrically operated oil valve for each of said nozzles, and a switch controlled by the said varying oil pressure for controlling said valves for efl'ecting their successive opening and closing.

5. An oil burning system comprising a plurality or nest of oil burner nozzles at one or more ilring openings of a furnace, an electrically operated oil valve for each of said nozzles. with one exception, means for supplying oil under pressure to said nozzleaanoil pressure valve controlled by the steam pressure generated by the furnace, for controlling the pressure of said oil, oil pressure operated switch mechanism for controlling said electrically operated valves, said switch mechanism being controlled by said oil pressure valve.

6. An oil burning system comprising in combination a plurality or nest of pressure atomizing oil burner nozzles at a firing opening of a furnace, means for supplying oil under pressure to said nozzles, an electrically operated oil valve for each of said nozzles, oil-pressure operated variable setting switch mechanism for said valves, an oil pressure valve for varying the pressure of the oil to vary the setting of said switch mechanism, and a connection from the steam line of the furnace to said oil pressure valve to vary the setting of the same and the setting of said switch mechanism to vary the operation of said electrically operated valves in accordance with variations in the steampressure.

THEODORE NAGIL.