US2286581A - Oil burner - Google Patents

Description

June 16, 1942." F 7 1.. L.'SCOTT Y 2,286,581

7' 01;. BURNER Filed Feb. 29, 1940 2 Sheets-$heet l IIQVEN'TOB L; L. scoTT June 16, 1942- OIL BURNER Filed Feb. 29, 1940 2 Sheets-Sheet 2 I INVESZZW H 0 Patented June 16, 1942 STATES PATENT OFFICE 01L BURNER Lewis 1. Scott, scheme, Mo. Application-February29, 1940, Serial No. 321,508 we iclaima (cuss-36.3) This invention relates to oilburners of the per gallon, and from the above it be 'seen general type as pressure oil burners, that it would be highly desirable to be able to whereby the oifis pumped under 100,# or more burn smallquantities of oil efllciently and with- UNITED pressure to a spray nozzle, and atomization takes place by virtue of the pressure on the oil through a 1.10.116 arranged for atomizingthe oil and pro- Jecting it in like form of anoil spray from the nozzle.

One of theobjects of this invention is toprovide a pressure type of oil burner that will burn what is commonly known as #3 fuel oil or lighter fuel oils reliably down to one half gallon per hour, and still at the same time provide a nozzle orifice and nozzle whirling slots of such area even when burning at one half gallon per hour, that said nozzle orifice and slots will be substantially non-clogging.

- change to anothersize.

1 partly in section. v

out nozzle blocking. It-is also desirablein an automatic burner to be able to adjust the oil fire nicelywithout having totake out the nozzle and v e accompanying vention. a v

Referring now to the drawings-,- Figure 1 is a plan view of my oil'bumershowri dra n s, illustrate my in Figure 3 is an enlarged view of the spray nozzle andconnected parts, on line 2-2 of Figure 1. Figure 3 is anenlarged view of the oil pipes and connections leading to and from the spray nomle.

Another obiect' is to Provide a burner that will be fully automatic and that willfunction without manual attention.

Another object is to provide an oil burner whereby the oil ratecan be adjusted to a small fraction of a gallon without the necessity of changing the spray nozzle as is commonly done in automatic pressure oil burners.

Another object isto construct the nozzle orifice of my oil burner so that there will be no dripping of oilfrom the nozzle during the spraying operation.

Variousother objects and advantages will be apparent from the following description, and the novel features will-be pointed out inthe ap-,

. burner that it is quite diflicultto successfully the spray nozzle 6; .e d V The pump! is connected to an oil supply, tanks ,7

operate a pressure burner down'to a gallonage' which will easily clog with any fine foreign matter that mightjbe in the oil. For this reason,

' most pressure oil burners only operate down to about one and one third gallons per hour,-and

erable nozzle lblockingfloccurs due'to the very small nozzle orifice, even though great care is exercised in filtering or screening the oil.

It is highly desirable to bum oil in small quantitles for oil buming water, heaters, and for heating plants used in smallhomes. Forv example, many' small homes have a heat "loss of between 40,000 and'50,000 ,B. t. u.s. The average #3 oil contains approximately 140,000 B. t'.'u .s

I Figure 4 is a sectional view of an automatic cut-off and pressure regulating valve connected in the return oil line from the nozzle taken on the line of Figure l. I I

Figure 5 is a cross section of the oil pump, takenon the line 5-5 of Figure 6.

Figure 6 is a crosssection of the pump taken on the line 8-6 of Figure 5.

Figure 7 is a front view of the nozzle whirler tip taken on the line 1-1 of Figure2. Referring now to the drawings. 1 an electric motor whichoperates a blower wheel (not shown) in the blower housing 2, which blower furnishes air to the oil spraytopromote combustion. 3 indicates a pump support secured to the blower housing}, and which carries the oil pended claims. g pump 4. 5 indicates an air blast tube which It is a well known fact that when attempting to carries the nozzle, nozzle pipe, etc; and which is burn #3 fuel oil in. the conventional pressure 88 adapted to direct the air from the blowerl around not shown, by the pipe I? The motor Hs adapt- 45 with the nozzles used at this gallonage, consided to .drive the pump shaft I in a well known manner. 9 indicates a conventional type of pump packing or seal. Hi indicates a well known type of pumpgears, which gears are'driven by I d the shaft 8, and are enclosed in'the-housing -ll which housing is provided with an end piat' cover l2, all of which parts are enclosed. in the e main pump casting jl, which pump casting! is provided with a cover plate It. ll indicates an oil screen for filtering the oil goinz nto'the pump.-,

Oil is. delivered from the discharge side of the pump gears to an-oil passage, not shown, which passage communicates with the chamber is (see Figure 6). a From the chamber I! oil will be delivered through the pipe I and through connece tion H to the inside oi'the member llg'thmugh g 7 pipe l8, through-the oil screen 2., through slots indicates- 2| in the member 2|A, through the chamber 22, through the nozzle whirler slots 23 in the member 23A, into the whirling chamber 24. Part of'the oil will be delivered through the nozzle orifice 25 in the nozzle 6, and a part of the oil will be returned to the pump or to the tank through the hole 26 in the member 23A, through hole 21 in the member 28, through hole 28 in tube 36, through the fitting 3|, through pipe 32, through the valve body 33, through pipe'34, into the suction side of the pump 4. It'is obvious that this by-passed oil could be returned to the oil tank instead of into the suction side of the pump 4.

As before mentioned, oil is delivered from the pump to the chamber I55. indicates a bushing in the pump 4, (see Figure 6) in which bushing isadapted to move the piston 36. The piston 36 is adapted to seat at one end against the member 3|jso as to form an oil tightseat between the end of the member 31 and the piston 36. The piston'36 is hollow, having one end open and carries a spring 38. 33 is a button which bears against one end of the spring 38, and the pressure on the spring 38 can be-varied by adjustment of the screw 46 carried in the member 4|,

secured to the-pump 4.; 42 indicates a slot in the bushing 35, which slot communicates with the passage 43, which passage 43 communicates with the hole 44 (see Figure 5). When the oil is pumped into the chamber |5, a pressure will be piston 36 away from its seat on the member 31,

which mov'ementiis resisted by the spring 38.. The piston will move away fromsaid seat until it uncovers the slot 42, so that part of the oil de- 'livered to chamber l5 will be lay-passed into the passage 43, and into the hole 44, and if the pipe plug 45 is removed, the by-passeci oil will return to the suction chamber 46 or the pump 4. If it is desirable to return, the by-passed oil to the oil tank,'then the pipe plug 45 will be screwed into its place, and the plug 46A will be removed and a" pipe not shown may be connected in the place of plug 46A, and will run. backto the oil tank. It .willbe obvious to those skilled in the art, that the piston 36 will act both as an oil cut-off valve and a pressure regulating valve, and that the pressure ofoil delivered to the pipe |6 will depend on the adjustment of the screw 40.

The oilby-passed from the whirling chamber 24 will return as before described tothe valve body 33, through the pipe 32.

' spring 52 contacts with the member 53, which member 53 bears against the diaphragm 41. The

' member 54is screwed into the valve body 33 and acts as a seat for the valve 55. The valve 55 has an enlarged head 56, which contacts with the diaphragm 41, which head 56 engages a spring 5'|, whlch spring rests on the member 58, which member is secured to the inner end'of the member 54. Oil returning to the inside of the valve body 33 through the pipe 32 will act on the diaphragm 4|, and the pressure developed in the chamber within the valve body 33 will cause said diaphragm 41 and valve 55 to move so as to permit oil to flow through the valve and into pipe 34 as 'before' described. Pressure in the chamber within the valve body 33 can be regulated by adjusting the screw 50, and it will be obvious that i the adjustment of the screw 58 will regulate the developed in said chamber l5, and will move the body 33 and the space around the valve seat of the valve 55. It will be noted that the valve is installed exactly as shown in Figure 4, so that the pipe 34 is on the upper side of the valve. The hole 33A will prevent any air from being trapped within the chamber of the valve body 33. Should any air be trapped in this chamber, there will be an after squirt of oil from the nozzle orifice 'each time the burner is shut down.

Referring now to Figure 3, 59 indicates packing arranged around the tube 30. The tube 36 has an enlarged portion 60, which serves as a stop for the spring 6| mounted around the tube 30. The member 62 is spaced between the spring 6| and packing 59. The pipe |9 serves as a stop for .the enlarged portion 60 ofthe tube 30 when the oil burner nozzle 6 is not in place, however, when the nozzle 6 is in place, the member 28 will engage the end of the tube 30 and will effect an oil-seal between the member 28' and tube 30, and "will press the tube backward, as shown in Figure 3, and compress the spring 6|, so as to exert pressure on the-packing 59 and effect a seal between the oilgoing to the nozzle 6 and oil beingby-passed through the tube 30. The nipple 63 is attached to the end of the pipe l9 and is threaded to receive the threaded portion of the nozzle 6' as clearly shown in Figure 2.

The oil screen 20 is secured to a head 64, which head, is arranged to fit nicely over the member 28. The other end of the screen 28 is secured to a head 65, which head is arranged to screw into 'the inner threaded portion of the nozzle 6. It

will be seen that any oil delivered from the pump 4 through the tube l3 will have to pass through thescreen 26 before going to the nozzle whirling chamber 24.

66 (see Figure 1) indicates a conventional air whirler mounted around the fuel tube I9, which whirler also acts to center the fuel tube in the air blast tube 5. 61 indicates the conventional electric spark igniter commonly used on oil burn- ,ers, which igniter receives electric current from the secondary side of a high voltage transformer (not shown) through wires 68.

I have found that in the operation of my oil burner, as illustrated in the accompanying drawings, that if I use a conventional nozzle orifice as shown by the dotted lines in Figure 2 for burning a small gallonage of oil, I get very poor spray and a poor fire and get constant dripping downward from the lower part of the nozzle. With the construction shown in full lines of my nozzle 6, (see Figure 2) I do not get tl'e dripping before mentioned, and I can get a highly efiicient fire down to as low as three tenths of a gallon per hour, which fire can be burned in a very small cc-mbustion'ch'amber. From repeated tests that I have run, I have found that performance of this nozzle depends primarily upon the size and shape of the delivery orifice, and that the ratio of the length to diameter of the orifice should be 7 a little greater than one, where the ratio of length to diameter of the orifice of the conventional nozzle used on pressure burners is usually between two and three. I have found further that the conventional bell mouthhas a tendency to cause the oil to follow the mouth and dribble off the nozzle shell instead of breaking freely away in a cone. This effect becomes so pronounced at low oil rates that there is practically no spray, with the oil all dribbling off the nozzle shell. I have further found that I can use relatively large nozzle orifices with a very ,low oil gallonage delivered to the fire.. I have also found that the nozzle whirler slots 23 can be, several times the area of normal slots used in small pressure nozzles. The greaterthe area of the nozzle slots 23, the larger can be the diameter of the hole 26 in the member 23A. For example, I

have taken the core member represented by the 32 down to as low as 10#. I have found that I get a greater oil delivery from the nozzle orifice when I have 100# pressure delivered from the pump to the nozzle slots 23 than I do when I have 200# pressure delivered from the pump to the nozzle slots 23 and when I keep the same relatively low pressure in the pipe 32, in both instances. This is due to the fact that with the higher pressure the oil is caused to whirl at much greater velocity in the whirling chamber 24, and

apparently sets up a resistance to the outward fiow from the nozzle orifice. The higher the pressure of oil to the nozzle slots23, the greater will be the whirling in the whirling chamber 24,

' and the better will be the atomization of the oil from the nozzle orifice.

I have found that it is essential, when the oil bumer is stopped, that the cut-off valve in the oil conduit from the pump to the nozzle slots 23 cut off at close to the maximum oil pressure being delivered by the pump, and that this cut-off valve should close before the cut-off valve located in the return by-pass line from the nozzle whirling chamber. If the cut-off valve located in the conduit from the nozzle by-pass whirling chamber should close first, then the maximum delivery of oil from the pump would o out the nozzle orifice, and, for example, if we were normally burning one half gallon per hour with say 200# pressure delivered from the pump to the nozzle slots 23 and the valve in the by-pass line from the whirling chamber of the nozzle should close first, we might get an oil delivery of four or five gallons per hour from the nozzle orifice,

" in the nozzle can be several times the area of the nozzle orifice, and the area of the by-pass hole,

can be varied according to the total area of the structed that said first named cut-off valve of the by-pass hole area to the total area of the whirler slots can be 2% to 1, and down to as low 7 I as A to 1. As anexample, I have successfully used a by-pass hole having an area of .00062 sq. inch, with a total whirler slot area of .000324 sq. inch, which is a ratio of the by-pass hole area to the total'slot area of about 2 to l. If with this same slot area I use a by-pass hole having an area of .00126 sq. inch, which is a'ratio of by-pass the whirland spoil the atomization of the oil' coming from the nozzle orifice.

I claim:

1. In an oil burner, a pumpfor pumping oil I at relatively high pressure, a spray nozzle, a, pipe arranged to conduct oil from the pump to the spray nozzle, a whirling chamber adjacent to the nozzle orifice, anoil by-pass pipe connected to said whirling chamber and arranged to by-pass oil from said whirling chamber to the suction side of the pump, an automatic oil cut-off valve arranged in the oil delivery pipe from the pump, a second automatic oil cut-ofi valve arranged in the oil by-pass pipe which connects to the nozzle whirling chamber, said valves being so concloses before the second named oil cut-oil valve when the oil burner is shut off.

2. In an oil'burner, a pump for pumping oil at relatively high pressure, a "spray nozzle, a pipe arranged to conduct oilfrom the pump to the spray nozzle, a whirling chamber adjacent to the nozzle orifice, an oil by-pass pipe connected to said whirling chamber and to the suction side of the pump, a combination oil cut-off and pressure regulating valve arranged in the oil delivery pipe from the pump, a second combination oil cut-oif and pressure regulating valve arranged in the oil by-pass pipe, said valve being so constructed that to said whirling chamber and to the suction side I of the pump, a combination oil cut-ofl and pressure regulating valve arranged in'the oil delivery pipe from the pump, a second combination oil cut-ofi and pressure regulating valve arranged in' the oil by-pass pipe, said valves being so constructed that said first named valve closes before the second named valve when the burner is shut off, the by-passed oil from both valves being returned to the suction sideof the pump.

4. In an oil burner, apump for pumping oil at relatively high pressure, a spray nozzle, a pipe arranged to conduct oil from the pump to the spray nozzle, a whirling chamber adjacent to the nozzle orifice, an oil by-pass pipe connected to the whirling chamber and to the suction side of the pump, an automatic oil cut-oil valve arranged in the oil delivery pipe from the pump, a second automatic oil cut-off v'alve arranged in the oil by-pass pipe, said second valve having a vent therein to prevent any trapping of air within the valve, said first named valve being constructed to close before the second named valve Y Y whirler slots. I have discovered that the ratio

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