Liquid Waste Burner

Abstract

A system for burning waste lubricating oil along with regular fuel oil in a conventional heating burner. The waste oil is supplied only after the burner has thoroughly heated up on burning regular fuel oil. A snorkel device is provided to assure that only liquids and no solids are drawn into the system. A constant displacement pump in the waste oil flow path serves the purpose of adjusting the ratio of regular fuel to waste oil. The waste oil is supplied directly to the swirl chamber of the burner nozzle.

Description

This invention pertains to methods and apparatus for disposing of combustible liquid wastes, such as spent lubricating oil, by incineration.

Generally, the invention is useful wherever it is necessary to dispose of any combustible liquid, such as, for example, spent quenching oils, waste cutting fluids, waste industrial lubricants, and the like. The invention was particularly developed for use in retail gasoline service stations wherein the accumulation of spent lubricating oil, such as is drained from automotive crankcases, becomes a problem in that large amounts are accumulated in the station. Thus, a primary object of the invention is the provision of means of incinerating such crankcase oil thereby relieving the service station operator from the burden of otherwise disposing of it.

The general approach of the invention is to provide a system wherein the waste oil or other combustible liquid can be burned, cleanly, along with regular fuel oil in the service station's heating system, so as to thereby not only dispose of the waste oil, but to additionally derive benefits from it, i.e., to derive whatever heating value the waste oil may contain. Another advantage of the invention is that it provides for separate storage of the waste fluid and the regular fuel oil, and causes them to mix together in the swirl chamber of the nozzle in the oil burner. In prior systems, wherein the two fluids are premixed, additional problems arise, including the need for frequent checking to keep the concentration of the blend within set limits to assure reliable ignition and combustion; entrainment of pollutants and solid contaminants which can cause nozzle plugging; and erratic flow rates caused by variations in the viscosity of the blend.

The invention allows the fire to be started with regular fuel oil only by providing time delay means before beginning the flow of waste oil to the nozzle swirl chamber. This feature provides the advantage that the burner apparatus is thoroughly warmed up on a regular fuel oil fire only before the waste oil begins to flow, thus assuring efficient incineration of the waste oil. Further, this system assures the station will be properly heated even if there is no waste oil to burn.

The invention also provides a modified standard nozzle having means therein to permit the burning of two fuels and to cause mixing of these two fuels in the nozzle swirl chamber only, while at the same time providing check means to assure that the regular fuel oil does not enter the waste oil system. That is, means ar provided to assure that the regular fuel oil is not contaminated with the waste oil until the two are mixed in the swirl chamber of the nozzle.

Since the waste oil does not flow through the nozzle slots, there is less tendency for the nozzle to clog and less tendency for the flow rate to change due to variations in fluid viscosity. The atomization of only regular fuel oil at start-up assures reliable ignition and good combustion performance independent of the physical properties of the waste oil.

The above and other advantages of the invention will become evident in the following detailed description and claims, and in the accompanying drawing also forming a part of the disclosure in which:

FIG. 1 is a general schematic view of a system embodying the invention;

FIG. 2 is cross-sectional view through the nozzle of FIG. 1; and

FIG. 3 is an electrical schematic diagram of the circuit portion of the system shown in FIG. 1.

Referring now to FIG. 1, reference numeral 10 designates the system generally, and system 10 comprises any conventional pressure atomizing gun type oil burner 12. The regular fuel oil to be burned in burner 12 is supplied in a conduit 14 from a conventional tank or other source of supply, not shown. A nozzle and adapter assembly 16 is housed within the burner 12 adjacent to the outlet end thereof, in the usual manner. The waste oil to be burned is supplied to nozzle 16 via a conduit 18. Conduit 18 includes, in series, moving away from burner 12, a delayed opening solenoid valve 20, a filter 22, and terminates at one leg of a four-way junction 24.

A pressure gauge 26 is positioned off of a second leg of junction 24, and a pair of conduits 28 and 30 extend from the remaining two legs of this junction 24. Conduit 28 includes only a pressure relief valve 32 and this line 28 terminates at one leg of a three-way junction 34. Conduit 30 extends between the junctions 24 and 34, and it includes an adjustable output constant displacement pump 36, indicated by the legend "C.D. Pump" on the drawing, a vacuum gauge 38, and another filter or strainer 40.

A line or conduit 42 extends from the remaining leg of three-way junction 34 to a tank 44 used to store the waste liquid to be incinerated in burner 12. Positioned in tank 44 is a snorkel device 46 to which the conduit 42 attaches. Device 46 is provided to assure that the waste fuel will be taken off of the top of the liquid level in the tank 44, to thereby enhance the settling out of solid particles. The snorkel protects the remaining system by reducing the possibility of solid particles being drawn into the system by pump 36 and fouling the various components.

All of the parts shown in FIGS. 1 and 3, with exception of the nozzle and adapter assembly 16, are standard "off-the-shelf" components and thus need not be described in any further detail herein. As an alternative arrangement, pump 36 and valve 32 could be replaced by a standard oil burner fuel unit having a built-in relief valve and constant pressure flow valve.

Referring now to FIG. 2, the nozzle and adapter assembly 16 is shown in more detail, and comprises an adapter body 46 having a nozzle housing 48 secured to its front end by suitable interacting threads. The nozzle is essentially the one of U. S. Pat. No. 3,272,441 by O. A. Davis, Sr. and B.R. Walsh, and assigned to the same assignee as the present invention.

Adapter body 46 has thread means 50 at its rear end to which the regular fuel oil conduit 14 is connected. The regular fuel oil passes through a passageway 52 in adapter body 46, and exits into a main chamber 54. Conduit 18 carrying the waste oil or other combustible liquid to be incinerated terminates at a block 56 which connects into a side opening 58 in adapter body 46. Side opening 58 connects to a central opening 60 which communicates with a stepped down portion of main chamber 54. Positioned within chamber 54 is a central nozzle member having a rear stud portion 64 which fits within the stepped down portion of chamber 54 described above. O-Ring 66 is fitted in a suitably formed groove in the stud portion 64 and forms a seal at this location between the regular fuel oil and the waste oil systems. Member 62 is formed with a through central passageway 68 for the waste oil from conduit 18. At its front end, central passageway 68 is enlarged as at 72, and this enlarged portion carries a ball check member 74 which is urged by a spring 76 towards a position to close passageway 68 from passageway 72. At the front end of enlarged portion 72, the nozzle includes a swirl pin 78. The spring 76 has its front end bearing against the rear surface of this swirl pin 78. On its outside surface, member 62 is formed with a plurality of slots 70 which form the passageways for the regular fuel oil to enter chamber 55 from chamber 54.

Swirl pin 78 is formed with a central passageway 80 which flows the waste oil passing therethrough to the swirl chamber 82 in the nozzle. The swirl pin is similar to that described in the above-identified United States Patent, particularly in FIG. 8 thereof, and comprises a plurality of swirl slots 84, but need not be described in any further detail herein. Other nozzles could be used, the criterion is that the waste oil be mixed with the regular fuel oil as late as possible, the swirl chamber 82 or equivalent being about the extreme limit of this deseratum. Nozzle housing 48 comprises a rear boss 86 which is threaded on both its inside and outside surfaces to serve to interconnect adapter body 46 with threaded portions 71 on the central nozzle member 62. The slots 70 in the central member described above define portions 71, making them into so-called "split threads." Such portions 71 are typically provided. At its front end, nozzle housing 48 comprises a central exit opening 88 from which the combination of the thoroughly mixed two fuels leave the nozzle and enter the combustion area in a finely atomized spray. Slightly rearwardly of this opening 88, housing 48 is formed with a circle of air aspirating openings 90, as described in the aforementioned patent. At the forward inside end of the nozzle housing, there is provided an orifice disc 92, on the inside surface of which the swirl pin 78 is positioned. The space behind the orifice disc and forward of the front face of the swirl pin defines the swirl chamber 82.

Generally, the regular fuel oil under pressure swirls through the swirl chamber 82 forming a thin film therein, and thereafter, as will be explained below, the waste oil is supplied to the central passageway 80 into the swirl chamber 82. Thus, mixing of the waste and regular fuel oils occurs only in the swirl chamber 82 and not earlier, thereby achieving the advantages of no premixing, and others as mentioned above.

Referring now to FIG. 3, there is shown a schematic diagram of the electrical portion of the invention, which is extremely simple, and many other similar and well-known circuits could be used. By way of example, there is shown a thermostat 94 connected to a primary control circuit 96 of any suitable conventional design. Circuit 96, as is known to those skilled in the art, will include a transformer, a relay, safety means, and the like, all of which need not be shown. A pair of lines 98 and 100 extend out of the primary control 96, and the remaining devices are wired in parallel across the lines 98 and 100. These devices include ignition means 102, the motor 104 in the gun burner 12, the pump 36 for the waste oil, and the delay opening solenoid valve 20.

OPERATION

In operation, the thermostat 94 signals when heat is needed. This signal, via primary control 96, immediately activates lines 98 and 100 to cause the burner motor and the ignition means 102, not otherwise shown, to start immediately thereby causing the fire to start up on regular fuel oil only. The constant displacement pump 36 also immediately starts to operate, but because valve 20 is still closed and will remain closed for its inherent time delay, the waste oil cycles around the conduits 30 and 28 and the junctions 24 and 34 until this valve "times out" and thereafter opens, then allowing waste oil to be fed to the nozzle. A constant displacement pump is used at 36 for its accurate delivery control capability, whereby the ratio of regular fuel to waste oil supplied to the nozzle can be accurately controlled.

Pressure gauge 26 is used to indicate changes in resistance to flow to the nozzle. Vacuum gauge 38 serves to indicate the extent of filter plugging. With delay valve 20 closed and pump 36 running, there must be relief of pressure by the opening of relief valve 32 or the pump will stall or break.

With regular fuel oil supplied to the nozzle at a typical pressure of 100 psi obtained from the burner fuel pump, not shown, a constant desired fuel flow rate for start-up is assured. When waste oil is introduced to the nozzle, total flow is approximately equal to the sum of both flow rates. There may be a slight fall off of regular fuel flow depending on the amount of waste oil added and its effect on nozzle flow resistance.

For example, as nozzle flow resistance goes up due to an increase in oil mix viscosity, the pressure regulating relief valve of the burner fuel pump will open wider to maintain the given nozzle pressure, thus, there will be some drop in regular fuel flow.

The waste oil bypass feature has several advantages. Primarily, it allows the burner 12 to warm up on regular fuel oil only. Further, this feature allows the waste oil to be "warmed up" by flowing through the bypass system before being allowed to pass through the nozzle, thereby making the waste oil less viscous and more flowable, while also subjecting the waste oil to refiltration. The bypass assures dependable starts with good atomization and ignition of the regular fuel; less filter plugging, minimum viscosity effects, and therefore a more nearly constant flow rate.

The filters 22 and 40 are provided as a safety means to protect the pump 36 and the nozzle assembly 16, respectively, from contamination. It is anticipated that the waste liquid in tank 44 will be quite dirty.

As mentioned above, virtually all the components are standard items of commerce. In the successfully constructed embodiment the key components were:

TABLE

Part Source Model Remarks Burner 12 Gulf Oil Corp. EJ-1 Econojet Valve 20 Honeywell Co. V4046A Uses thermistor for time delay Filter 22 Fulflo Filters, Inc. FB-4 20 gph -- 50 micron size Gauge 26 U.S. Gage Co. -- 0-100 psi Pump 26 Zenith Pump Co. B-4407 0.20 to 1.00 gph Valve 32 Lunkenheimer Co. -- opens at 50-100 psi Snorkel 46 Klear Flow Lines, for 275 gallon Inc. -- obround tank Thermostat 94 Robertshaw CM-260 low voltage Controls Co. switch Primary Honeywell Co. R 8184 constant igni- Control 96 tion, cad-cell flame detector

In this successfully constructed embodiment, valve 20 was set for a delay of about eight seconds. This feature is adjustable dependent upon the regular fuel supply and the waste liquid to be burned.

While the invention has been described in detail above, it is to be understood that this detailed description is by way of example only, and the protection granted is to be limited only within the spirit of the invention and the scope of the following claims.

Claims

1. A system for burning two liquids in a single burner apparatus comprising a burner apparatus, means to supply a first liquid to the burner apparatus, means to supply a second liquid to said burner apparatus, said supply means for said second liquid including time delay means whereby the burner apparatus begins operation with said first liquid and thereafter continues operation with both said first liquid and said second liquid, said burner apparatus comprising a nozzle having a swirl chamber therein, means to bring said first and second liquids together in said swirl chamber, and spring loaded ball check valve means to permit the flow of said second liquid into said swirl chamber and to prevent the flow of said first liquid into the portions of said nozzle which carry said second

2. A system for burning two liquids in a single burner apparatus comprising means to supply a first liquid to the burner apparatus, means to supply a second liquid to said burner apparatus, and said supply means for said second liquid are adapted to begin operation with said first liquid and thereafter continue operation with both said first liquid and said second liquid and comprise a tank for said second liquid, a delay solenoid valve which controls the flow of said second liquid from said tank to said burner apparatus, a pump connected in series between the tank and delay solenoid valve, a bypass loop connected into the supply means for said second liquid between the pump and delay solenoid valve, whereby said pump and said burner apparatus may be started at the same time and said second liquid flows around said bypass loop until said delayed opening solenoid valve times out and permits said second liquid to flow to said burner

3. The combination of claim 2, said pump comprising an adjustable constant displacement pump, whereby the ratio of said first and second liquids

4. A system for burning a fuel and a combustible waste liquid in a single burner apparatus comprising a burner body having an exit end, an exit opening centrally positioned at said exit end, a central waste liquid passage extending through the burner body to the exit end thereof, a swirl pin closing the exit end of the central waste liquid passage, said swirl pin having a centrally located flat exit end and a conical surface extending from the periphery of the flat exit end away from the exit end of the burner body, a central duct through the swirl pin communicating with the central passage, an orifice disc having a central opening adjacent to the central exit opening and a concave conical surface adapted to fit against the conical surface of the swirl pin, a swirl chamber between the flat exit end of the swirl pin and the conical surface of the orifice disc, angularly oriented grooves in the conical surface of the swirl pin extending from the periphery thereof to the swirl chamber, an annular fuel chamber communicating with the ends of the grooves remote from the swirl chamber, air aspirating passages through the burner body opening into the space between the central exit opening and the opening in the orifice disc, pumping means for delivering the combustible waste liquid to the central passage, and means for delivering fuel to the annular fuel chamber.