US2199454A - Means for preheating oil for oil burners - Google Patents

Description

May 7, 19 R. F. ANDLER ET AL MEANS FOR PREHEATING O IL FOR OIL BURNERS 2 Sheets- Sheet 1 Filed Nov. '15, 1939 May 7, 1940. R. F. ANDLER El AL MEANS FOR PREHEATING OIL FOR OIL BURNERS Filed Nov. 15, 1939 2 Sheets-Sheet 2,

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Patented May 7, 1940 PATENT orrlcs MEANS FOR PREHEATING OIL FOR OIL BURNERS Robert F. Andler, Rutherford, N. J., and George R. Koeln, Atlanta, Ga., assignors to Electrol Incorporated, Clifton, N. .L, a corporation of Delaware Application November 15, 1939, Serial No. 304,460

2 Claima- Our invention has for its object a certain new and useful improvement for preheating oil in order to obtain a more complete atomization of the oil when it is sprayed from a nozzle.

It is a recognized fact that, in order to obtain a desirable combustion, it is necessary to break the oil up into fine particles. This is accomplished nozzle at a very high rate of speed; this speed' breaking up the fine particles.

This method is generally satisfactory where a light oil is beingburned but if itis desired to use a heavy viscous oil it has been found in practice there is a lack of rotation or turbulence which no doubt is due to the viscous quality of the oil. The result is that the oil-may issue from the nozzle in a very poor spray or even in a solid stream approximating the size of the lead in a pencil.

In order to overcome this objectionable feature, the heavier oils are heated, which, as is understood, reduces the viscosity of theoil to a point comparable to the lighter grades of oil. Such a preheating system is described in the patent to Scott No. 1,640,729. The difliculty of this system and similar ones is since the same rate of heat prevails whether 1 /2 gallons of oil are burned per hour, or 8 gallons per hour, such a preheater,

with light loads,'would build up terrific heat and cause the oil to crack depositing carbon which wouldeventually plug the nozzle.

Another objection was that when the burner was started it was found in practice that there would be considerable cold and consequently heavy oil in the tube leading to the nozzle cut-oil valve as well as in the line leading from the heater to the cut-off valve if one is used. As a consequence, when the burner was started this residue of cold oil would be sprayed into the combustion chamber, but due to its viscosity it would not be sumciently atomized to ignite. When the oil which had been heated in the heater reached the nozzle, ignition would take place and the cold all previously sprayed into the combustion chamher would also ignite with a disturbing force.

Our invention has for its principal object to provide means not alone to preheat the oil, but

also to provide a construction which will prevent any cold oil reaching the nozzle.

A further object is to provide means to cause a continuous circulation of the oil so that no cold oil will remain in the burner, nor reach the nozzle until it has reached the required temperature.

Another object is to provide an automatic control to cut oil the heat when the oil has attained the proper degree of heat.

A further object is to provide a supplementary heater in which the oil may be heated by the boiler water, in this way we conserve the electricity used in the preferred form of preheater.

A further object is to provide a by-pass valve, of the well-known thermostatic type, which will remain open while the cold oil is passing through it but which will automatically close when the oil reaches the proper temperature.

I A further object is to so construct the by-p valve that it will permit the oil to rush through the valve without closing the valve, even though the tendency is to close it.

We design the by-pass valve so that the area of the valve needle acted on by fluid pressure when the valve is closed is such that the force .exerted by the fluid pressure, tending to hold the ing reference to the accompanying drawings,-

which are hereunto annexed and are a part of this specification,- in which:

Fig. 1 is a more or less diagrammatic view of an oil burner equipped with our improvements, some of the parts being shown in section;

Fig, 2 is a somewhat similar view showing also the supplementary heater; and v Fig. 3 is a detail plan view of the thermostatic disc used in the system.

Similar reference numerals refer parts throughout the entire specification.

. As shown in the drawings, we provide a reservoir i which is connected to a suitable oil supply (not shown) by a pipe 2 which leads from a pressure regulating valve 3 to control the pressure of the oil in the reservoir I. We mount our heater 4 which is preferably an electric one inside of the reservoir i. Suitable binding posts 5 and 6 mounted on an insulating block are proto similar vided for connecting the electrical conductors (not shown). An automatic thermally actuated control I is mounted in the reservoir 1 preferably adjacent the top. It is connected in line with the heating element 8 so that when the oil is heated to the proper temperature it will automatically cut off the current, until the temperature of the oil falls below that at which proper atomization of the oil is attainable when it will again out in. A port or passage 8 is provided at the top of the reservoir and leads to a suitable strainer 8 mounted in a chamber I8 formed in the reservoir I. A port or passage ll leads from the chamber III to a pipe l2 which carries theoil to a second strainer l8 through which the oil passes into. a chamber H formed in the body I! of the cut-oil valve. This valve body i5 is provided with a valve cap l8 and a diaphragm ll of any of the standard types on the market. This diaphragm ll does not move in constant deflection with the application of pressure thereto. After a certain pressure has been reached, its position changes with a snap and bows on the other side. A coil spring I8 is mounted in the valve cap it and exerts a pressure upon the diaphragm H. A screw I8 provides convenient means of adjusting the pressure of the spring II. The head 28 of the screw 18 is enclosed in a screw cap 2| to prevent the accidental changing of the pressure after it has once been set. A valve stem 28, having a needle valve 28 at its outer end, is secured to the diaphragm ll. The needle valve 25 opens and closes a seat formed in a wall in the tube 26 adjacent its outer end. A port 25a is formed in this wall and leads to a spray nozzle 25b of standard construction mounted in the outer end of the tube 28. The stem 24 is provided with a ball head 22 which abuts the diaphragm H. A socket seat 28 mates with the ball head 22. This construction permits the spring 28a to cock on the head without putting a strain on the valve stem. The stem 24 is inside of and spaced from a tube 26. This tube 28 is connected by a pipe 21 to a by-pass valve 28, the purpose of which is to by-pass the cold oil back through pipe 28 to the source of supply, thus permitting a circulation of the cold oil without its ever reaching the burner nozzle.

The operation of our invention is as follows: The pump is started and the various pipes and reservoir are filled with cold oil. A switch (not shown) is then closed and current passes through the heating element 4. When the temperature oi the oil is raised sufficiently to be properly sprayed, the control I will cut oil the current. The cold oilflows freely through the space intermediate sleeve 28a and the valve stem 24 into the tube 28 and back through the pipe 21 to the by-pass valve 28 thence to the source of supply. The sleeve 28a is fitted to the inner end of the tube 26 and is provided with a coil spring to equalize the pressure on the diaphragm ll.

When the oil has been raised to the proper temperature, the by-pass valve 28 will be closed by actuation of the thermal disc 80, which is provided with perforations 80b to equalize the pressure on both sides thereof. When this takes place, pressure is built up in the line and in the chamber ll of the cut-off valve and when this pressureexceeds that of the spring I8 which holds the needle valve 25 to its seat, the needle valve 28 will open and the hot oil will pass through the port 25a to the burner nozzle 25b, which will spray it into the combustion chamber (not shown). Naturally, with no oil flowing through the by-pass valve 28, the temperature will drop.

Howeven the by-pass valve 28 is so designed that it will not open until pressure is released and excess of the latter.

will not close again until the desired temperature is reached. We accomplish this by determining the force exerted bythe action of the bimetallic disc 88 when subjected to a variation in temperature and then designing the area of the valve needle 88a exposed to fluid pressure when the valve is closed so that the pressure exerted by the oil will be greater than any force exerted by the disc 88, which, being perforated, is not aiiected by pressure changes. We thus prevent the valve from opening upon a drop in temperature.

It will be clear from the foregoing that no cold oil can reach the nozzle since the needle valve 28 will close whenever the pump isshut down and there is a drop in the pressure which has been built up by the closing of the by-pass valve 28. This needle valve 25 will not again open until proper atomizing temperature is reached which will cause by-pass valve 28 to again close.

In practical operation of our invention, we have found even with the automatic control 1 operating to cut off the current when the desired temperature is reached, that the cost of heat from electricity, as compared to the cost of heat generated by the oil burner, was largely in We therefore provide a supplementary heater clearly shown in Fig. 2. As shown in this figure, we carry the oil irom the pressure regulating valve 3 through a pipe 82 to a coil 38 preferably formed of copper pipe which is mounted in a casing 84, which is suitably connected to a boiler 88 (only a fragmentary portion of which is shown as it forms no part of our invention) by means of flow and return pipes 86 and 81 respectively. The heated oil from the coil 88 passes through pipe 88 to the reservoir. The operation is Just the same as has already been described with the exception that since a thermostatic control in the boiler water will always maintain a certain temperature by operation of the burner; therefore, as the oil passes from the pump through coil 88 a certain amount of heat is picked up and carried to the reservoir. This means that the heating element therein will be cut off by the control I when the proper temperature has been reached. In practice we have found that after the burner has been in operation a sufilcient length of time to heat the water in the boiler, the oil passing'through the coil 83 will absorb heat enough to raise its temperature so that the, oil will spray freely and from then on no additional heating is required, consequently no electric current is needed to preheat the oil. In this manner, the amount of electric current used is materially reduced. It

- will be obvious to persons skilled in the art that in this way we can run a constant temperature due to the setting of the control I, the operation of which is directly controlled by the temperature of the oil, not by the temperature of the water in the boiler 88, for when the temperature of the oil falls, the control will snap on at once regardless of the temperature of the boiler water.

Although we have described with considerable detail the specific details of the apparatus, it should be understood that such description is solely for the purpose of disclosing a preferred embodiment of our invention and shall, in no.

sense, be deemed as limitations thereon.

This application is filed as a continuation in part of our copendng application Serial No. i32,- 490, filed March 23, 1937.

What we claim and desire to protect by Letters Patent is:

, a by-pass conduit for recirculating oil within the supply system and through: said preheating means, whereby so long as said by-pass conduit is open sufllcient pressure to cause said cut-off valve to open cannot be developed, and a thermally actuated valve adapted to close said bypass conduit when the temperature of the recirculating oil is sufliciently high to permit proper spraying, said by-pass valve being so designed that oil pressure in the supply system built up when the by-pass valve is closed will hold said valve closed despite any force tending to open it developed by its thermally responsive actuating mechanism.

2-. In a system for burning oil too viscous to be properly sprayed at normal temperature, the

combination of a spray nozzle, means for oplying oil under pressure thereto, means for preheating the oil, a pressure actuated cut-off valve adapted to prevent admission of oil to the spray nozzle until a predetermined pressure has been developed in the supply system, means including a by-pass conduit for recirculating oil within the supply system and through said preheating means, whereby so long as said by-pass conduit is open sufiicient pressure to cause said cut-off valve to open cannot be developed, and a thermaily actuated valve adapted to close said bypass conduit when the temperature of the recirculating oil is sufliciently high to permit proper spraying, said by-pass valve being so designed that the oil pressure acting on the area of the valve needle exposed thereto when the valve is closed exerts a force tending to keep the valve ROBERT F. ANDLER. GEORGE R. KOELN.

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