US2489823A - Liquid fuel burner nozzle - Google Patents

Description

EHLSENMNGER' LIQUID FUEL BURNER NOZZLE Filed Mgrch 27, 1946 Ngv, 29, 1949 Patented Nov. 29, 1949 LIQUID FUEL BURNER NOZZLE Earl Joseph Senninger, Chicago, Ill., assignor to Sanmyer Corporation, a corporation of Illinois Application March 21, 194s, serial'No. 657.358

claims. (cl. 299-140) While my invention relates broadly to systems for producing and discharging mixtures of liquids and gaseous fluids, with special reference to spray systems, it is especially advantageous for liquid fuel burner systems, and, for the purpose of the present disclosure, will be so described.

In a .fuel burner system of the present type fuel, oil and compressed air is delivered to a fuel nozzle by separate passages for intermixture and ultimate discharge in spray form, the liquid fuel usually being subjected to preliminary heating, for example by an electric heating element.

One common need for improvement in these systems is the venting of the liquid passages and the deaeration of the liquid preliminary to operating periods. This need is especially marked in burner systems that characteristically operate only intermittently, as in the case of domestic heating systems operating under thermostatic n need by providing for automatic preliminary deaeration flow of the liquid through a nozzle bypass in preparation for each period of combustion operation. The location of the by-pass is important because placing the by-pass for deaeration any distance from the burner nozzle necessarily means omitting a portion of the fuel line from the deaeration effect.

A second need for improvement in systems of the present type is to avoid nozzle leakage arising from residual heat after the termination of an operating period. When the burner system is deenergized the heating element maintains a relatively high temperature for a short period of time, and the consequent local expansion and evaporization in the associated fuel line usually displaces fuel towardthe burner nozzle with consequent dripping and carbon formation at the nozzle orifice.

Another object of my invention is to prevent this delayed-action displacement to the nozzle orifice during idle periods by placing a valve in the fuel line between the heating element and the nozzle orifice. Fortuitously the locating of the fuel by-pass at the nozzle to meet the first-mentioned object of the invention, viz: complete 2 aeration of the fuel line, facilitates the attainment of this second object of preventing drip. In this regard a feature of the invention is the employment of a three-way nozzle valve having one position for normal combustion operation and a second position for idle periods at which second position the three-Way valve completely cuts off the nozzle orifice and places the fuel line in communication with the by-pass.

One diliculty in spraying some kinds of liquids in fuel burner systems, as well as in other systems, is the tendency for the liquid valves to become clogged, especially when highly viscous liquids are employed.

A further object of my invention is to avoid this difficulty, along with certain other troubles, by periodically flushing the liquid valve with a gaseous fluid. In the preferred practice of the invention it is my purpose-to flush the nozzle valve periodically by reverse air flow.

A still further object and feature of my invention is to employ a three-way nozzle valve so constructed as to provide automatically for the reverse air flow at an intermediate position of the valve both immediately before and immediately after a period of combustion operation.

The above and other objects and advantages of my invention will be apparent in the following I detail description taken with the accompanying drawing.

In the drawing, which is to be regarded as merely illustrative, the accompanying figure is a longitudinal sectional view of an air tube and burner nozzle employed in the preferred practice of the invention, certain pertinent parts of the system associated with the nozzle being shown diagrammatically.

This invention may be applied to any convene tional oil burner, although I prefer to use it in conjunction with the type of oil burner shown in my prior patents Nos. 2,397,986, 2,397,987, and 2,397,988, of which. this case is a continuation-inpart, and my copending application Ser. No. 657,359, filed March 27, 1946, the disclosures of whichr patents and application are incorporated herein by reference. Referring lnow to the drawing, the oil burner nozzle assembly comprises a primary air supply line or tube I1, a nozzle I8, an oil supply line I9, a heater 20 associated with the oil supply line I9, and a pair of electrodes 2l- 3 associated with the nozzle for igniting the mixture of oil and air in starting the burner. An air pump shown diagrammatically at 24 supplies primary air to the nozzle through fitting 32, a blower `(not shown) supplies secondary air, and a motor (not shown) drives an oil pump 25 which provides oil under pressure to the nozzle. The fluid course or gaseous supply passage for the primary air has relatively large storage capacity. which capacity insures an even flow to the nozzle. It is important that the iiuid course have a sufficiently large total volume relative to the flow capacity of the nozzle orice 28 to serve as a reservoir for maintaining flow through the nozzle orifice for a substantial period of time after the air supply to the fluid course is cut off. Oil for fuel is stored in a suitable fuel supply tank and is led therefrom through pipe 38 to the oil pump 25, which is preferably combined with an air pump 24 in the manner disclosed in my copending application Ser. No. 657,359, entitled Dual pump, filed concurrently herewith. Where gravity feed cannot be used, an auxiliary pump (not shown) should be provided to boost oil from the supply tank to the oil pump. The oil pump 25 delivers the fuel oil through the supply line 39 and the previously mentioned pipe i9 to a threeway valve that is concealed in the nozzle |8 as shown in the drawing. The three-way -valve is governed by an actuator or automatic valve control 4|. At the idle or non-operating position of the three-way Valve, the end of the oil supply pipe i9 at the nozzle i8 is placed in communication with a by-pass pipe 42 that leads from the nozzle |8 back to the fuel oil supply tank. In response to rise in pressure in the air supply pipe 32 the automatic control 4| moves the three-Way valve to its normal operating position, thereby to place the end of the, oil supply line 29 at the nozzle i8 in communication with the nozzle orice 28. When operation of the described arrangement is started, oil discharged from the pump 25 through the supply pipes 39 and |9 is initially by-passed at the nozzle back to the supply tank through the by-pass pipe 42. .As soon as suiiicient pressure is built up in the fluid course to insure proper delivery of primary or atomizing air to the nozzle i8, the pressure-responsive actuator will react to the rise in air pressure by operating the three-way valve in the nozzle 8 to cut oi the by-pass pipe 42 and to open communication to the nozzle orifice 28, whereupon a fuel mixture of oil and air is sprayed from the nozzle for combustion. When, for any reason, the air pressure in the fluid course drops below that for which the device is designed and adjusted, the pressureresponsive actuator 4| will operate the three-way valve in the nozzle to cause the oil discharged by the pump 25 to be returned to the supply tank by the by-pass pipe 42. f

Automatic valve control As shown in the -drawing, the interior of the housing formed by the two body sections 89 and 81 of the Valve control 4| is divided by a flexible diaphragm 9| into what may be termed an air chamber 92 and a spring chamber 93. The springl nut |02, extends through the bushing 0l in abutment with the outer end of the spring |00.

The inner body section 81 of the valve control 4|, into which the air tube I1 is threaded, encloses a second smaller follower |03 in abutment with the diaphragm 9|. This second follower |03 has a tubular stem |05 that is slidingly guided by the bore leading to the air tube I1, and preferably suitable grooves |06 are formed in the surrounding guiding walls to provide free communication between the air chamber 92 and the interior of the air tube |1.

Seated in the tubular stem |05 of the follower |03 is the reduced end |01 of a valve control rod |08 that extends through the air tube |1 and forms with` the air tube an annular air passage ||0. In the other end of the control rod |08 a socket is formed to receive a tubular fitting H2, the tubular fitting having a radial iiange I3 in abutment with the end of the rod. A suitable helical spring I5 is seated against the radial flange ||3 to continuously urge the control rod |08 toward the diaphragm 9|, but this spring H5 is substantially weaker than the previously mentioned spring |00. Seating in the tubular fitting ||2, and secured therein by a pin |04, is the stem |09 of the valve member i4 of the previously mentioned three-way valve in the nozzle.

A suitable fitting H5 is threaded into the outer body section 86 for connection with the previously mentioned pipe 32. Suitable registering bores in the two body sections 89 and 81 form a longitudinal passage l I1, which passage joins a radial bore ||8 to provide for air flow from the fitting ||6 to the annular air passage I0 in theair tube il. The radial bore ||8 is closed at its outer end by a suitable plug |20, and is in communication with the air chamber 92 through a short bore l2 l.

l It is apparent that pressure changes in the previously mentioned duid or air course that ncludes an air chamber in the burner, the pipe 32, and the air tube |1 will be transmitted to the air chamber 92 to act against the diaphragm 9|.

. The air pressure against the diaphragm is reinforced by the spring l I5. The relative magnitudes of the forces involved is such that in the absence of substantial pressure in the air chamber 92 the spring |00 will cause the control rod |08 to hold the valve member ||4 in its outer limit position, i. e., the limit position to the right as viewed in the drawing. Whenthe pressure in the' air chamber 92 rises in response to rise of pressure in the air supply pipe 32, the spring |00 is compressed and the valve member ||4 moves to its inner limit position, or to the left as viewed in the drawing.

Nozzle construction into the outer end is threaded a nozzle fitting |26 having the previously mentioned nozzle oriice 28. Fixedly mounted in the rinterior of the tubular body is a cylindrical liner |21 that is cut away as shown at the two ports |23 and |25.

The three-way valve that responds to the valve 4 control 4| includes a valve chamber |30 opposite the port |23, which valve chamber is formed by 'the liner |21, a bushing |3| threaded into the outer end of the liner, and a valve core |32 that ananas is xedly mounted in the liner. has an axial bore 33 for ow of huid from the valve chamber |30 to the nozzle orlce 28. The

The bushing l |3| ferential clearance, as well asend clearance, into pression between the nozzle core and the bushing l |3|. It .will be noted that the bushing I3| Iis smaller in diameter than the surrounding cylindrical Wall of the tubular body |22, and that the The annular chamber |40 communicates with the nozzle orice 28 through a serlesvof channels formed by peripheral grooves |4| in the nozzle core |38, and also communicates with the nozzle orifice through the axial bore |31 and one or more openings |42 from the axial bore |31 to the periphery -of the nozzle core. It will be noted that the forward end of the'nozzle core isspaced inward from the nozzle orifice 28 and is formed with a small conical projection |43 coaxial with the nozzle orifice 28.

The valve core |32, which is bored to slidingly embrace the valve stem |09, is formed with a valve seat |45 at its forward end and is cut away to provide a iiuid passage |48 from the valve seat to the port |25 in which the by-p-'ass pipe 42 is threaded. Preferably the valve stem |03 is surrounded by suitable packing |41, which packing is placed between the valve core |32 and a suitable annular member |48. The previously mentioned spring is in compression against the annular member |48 to place the packing |41 under suitable pressure.

Air from the annular passage 4| I0 inthe tube |'l flows into an annular chamber |50 surrounding the valve stem |09 and is then conducted to the forward annular chamber |40 through a passage |5| formed in the wall of the tubular body |22. l

The drawing shows the valve member |4 in an intermediate position. When the valve member ||4 is in its forward limit position, i. e., to the right as viewed in the drawing, it is seated in the forward valve seat |45 to cut off the valve chamber |30 from the nozzle orifice 28. At such time fuel ol may flow from the oil line I9 through the valve chamber |30 and through the iiuid passage I 46 into the by-pass 42. On the other hand, when the valve member I |4 is in its extreme rearward position, or to the left as viewed in the drawing, it is seated in the valve Seat |45 to cut off the valve chamber |30 from the by-pass 42. At such time fuel oil may fiow from the oil `line i9 into the valve chamber |30 and through the axial bore |33 of the bushing |3| into the interior of the nozzle core |38 for ultimate discharge through the nozzle orifice 28. In moving from one of the two valve seats to the other the valve member ||4 passes through a short range of intermediate positions, at which positions the valve chamber |30 is simultaneously in communication with the oil line I9, the yby-pass 42 and the nozzle orifice 28.

Thenozale action bushing together with the small tube |38 forms y an annular chamber |40 in the tubular body.'

vary, say, from tive to thirty pounds per square inch for different installations.\ For the purpose of explanation let it be assumedhat the normal operating pressure for the air supply is fifteen pounds. The normal operating oil pressure may be of approximately the same magnitude.

.When the apparatus is idle between combustion periods the valve member ||4 is, of course, in its 'forward limit position, cutting off the nozzle orifice 28 'from the valve chamber |30. In response to thermostatic. control, or other control, the oil pump and the air pump 24 start simultaneously, 'and immediately oil flows from the oil line I9 through the three-way valve into the by pass 42 to return to the fuel supply tank. Initial by-pass flow will serve to deaerate the fuel oil that has been standing in the oil supply pipes 38 and |9. During this initial by-passing period the heater 20 is energized to raise the temperature of the by-passing oil, and the increase in temperature is helpful to a certain extent in the deaeration.

During this initial period of time in which the valve member ||4 is effectively seated in its forward position the air pressure gradually builds up in the fluid course. As -a result of the rising pressure the air iiows with increasing velocity out of the nozzle orifice 28. When this rising air pressure reaches, say, approximately one-third of normal pressure, or ve pounds per square inch, the corresponding rise of pressure in the air chamber 92 of the valve control 4| causes the valve member ||4 to be moved from its forward limit position to its rearward limit position.

An appreciable period of time is required for the valve member to complete this movement between its limit positions, and during such period of time the valve chamber is open not only to the oil supply line |9 and the by-pass 42 but also to the nozzle 28. Because the oil may escape from the valve chamber to the by-pass 42 with relative freedom the liquid pressure in the valve chamber, during this transition period, is relatively low and therefore a substantial portion of the air supplied to the for-ward end of the nozzle t kes a path of relatively low resistance back Y through the small tube |36 and axial bore |33 inti` the valve chamber |30, the air passing out through the by-pass 42. This reverse flow of the air flushes out the forward valve seat and produces agitation to ilush out the whole valve chamber. The momentary acceleration of flow through the by-pass 42 created by the additional air also tends to flush out the by-p'ass 42.

When the valve member i4 completes its rearward movement to seat in the rear valve seat |45. the oil pressure in the valve chamber |30 immediately rises to the norma-l operating magnitude and oil is discharged forward through the small tube |38 for mixture with the atomizing air prior to discharge from the nozzle orifice 28. The nozzle core |38 is of a conguration to cause the mixed liquid and air to whirl in a vortex in the spaceA immediately back of the nozzle orifice 28 for efiicient spraying action.

At the end of a combustion period when the air pump 24 and the oil pump 25 are deenergized simultaneously the oil pressure in the valve chamber |30 drops sharply, but the air pressure in the fluid course for supplying air to the nozzle drops relatively slowly because the volume of the air course is large relative to the release capacity of the nozzle. At this time, while the valve member ||4 is at its rearward position, the flow of air 7 to the nozzle orifice 28, through and around the nozzle core |38, tends to clear oil out of the forxward spaces of the nozzle, such oil being consumed as the burner flame dies out.

When thev air pressure in the fluid course drops to approximately flve pounds the corresponding drop in the air chamber 92 causes the valve member I I4 to be moved forward to the forward valve seat |35 to cut ofi the valve chamber |30 from the nozzle orifice. In the time period of appreciable duration in which this forward movement occurs, the valve chamber |30 is again open to the nozzle orifice as well as to the oil supply pipe I9 and the by-pass 42, and again reverse air flow is set up through the small tube |36 and the axial bore |33 into the valve chamber |30. The reverse flow of air sweeps residual oil in the forward portion of the nozzle with concentrated effect on the small tube |36 and the axial bore l33. At the comple, tion of the forward movement of the valve member l I4 no quantity of oil remains forward of the valve chamber |30 to cause any dripping of oil from the nozzle during the subsequent idle period between combustion operations.

After the valve member H4 reaches its forward limit position, thereby cutting ofi the valve chamber |30 from the nozzle orifice, residual heatin the heating element continues to heat the oil in the supply pipe I9, but any expansion or evaporization arising from such delayed temperature rise cannot cause dripping from the nozzle since the nozzle orifice is cut off from the oil line. The by-pass #32 is open, however, to provide a vent or release passage for such delayed expansion or evaporization of the fuel in the supply line.

My description in specic detail of the preferred practice of the invention lwill suggest to those skilled in the art various changes and substitutions within the scope of the appended claims.

l claim as my invention:

yliquid from said orifice.

3. In an apparatus of the character described l for discharging a mixture of a liquid and a gasl. In an apparatus of the character described for discharging a mixture of liquid and gaseous fluid, a nozzle having a discharge orifice, a gaseous supply passage leading to the nozzle, a bypass connection, a valve chamber having-two openings therein, a valve in said chamber'movable between a position where said means will obstruct one of said openings to a position where it will obstruct the other of said openings, one of said openings communicating with said orifice, the other opening communicating with the bypass connection, a liquid supply passage leading to said valve chamber, means to deliver liquid to said supply passage, and means to apply heat to the liquid supply passage, the point of heat delivery being between said delivery means and said valve chamber whereby movement of the valve to the position of obstructing the opening communicating with the nozzle causes any sublsequent expansion by heat in said liquid supply passage to be relieved through said by-pass instead of through the nozzle orifice.

2. In an apparatus of the character described for discharging a mixture of liquid and gaseous fluid, a nozzle having a discharge orifice, a gaseous supply passage leading to the nozzle, a bypass connection, a valve chamber having two openings therein, a `valve in said chamber movable between a position where said means will obstruct one of said openings to a position where it will obstruct the other of said openings, a liquid supply passage leading to said valve chamber, means to deliver liquid to said supply passage, and a heater in heat exchange relationship with theliquid in said liquid eous fluid, a nozzle having an orifice, a valve chamber, a nozzle passage for communication between said valve chamber and said orifice, a liquid supply passage to said valve chamber, a by-passrleading from Asaid chamber, a valve in the chamber movable between an idle position and a normal operating position, the idle position of the valve placing the liquid supply passage in communication with the by-pass while cutting off the nozzle passage, and the normal operating position placing the liquid supply passage in communication with the nozzle passage while cutting ofi the by-pass from the liquid supply passage, said valve also having an intermediate position in which the liquid supply passage is in communication with both the nozzle passage and the by-pass, means for moving the valve through its range of positions, and means in communication with said nozzle passage for providing gaseous fluid under pressure to said nozzle passage, whereby when the valve is in its intermediate position, the pressure of the gaseous fluid will cause a portion to fiow in reverse direction through said nozzle passage to the by-pass to thereby ush the nozzle passage.

4. In an apparatus of the character described for discharging a mixture of a liquid and a gaseous fluid, a nozzle having an orifice, a valve chamber, a nozzle passage for communication between said valve chamber and said orifice, a liquid supply passage to said valve chamber, a by-pass leading from said chamber, a valve in the chamber movable between an idle position and a normal operating position, the idle position of the valve placing the liquid supply passage in communication with the by-pass while cutting o the nozzle passage, and the normal operating position placing the liquid supply passage in communication with the nozzle passage while cutting oi the by-pass from the liquid supply passage, said valve also having an intermediate position in which the liquid supply passage is in communication with both the nozzle passage and the by-pass, means for moving the valve through its range of positions, means in communication with said nozzle passage for providing gaseous fluid under pressure to said nozzle passage, whereby when the valve is in its intermediate position, the pressure of the gaseous fluid will cause a portion to flow in reverse direction through said nozzle passage to the by-pass to thereby flush the nozzle passage, and sealing means interposed between the inner end of the nozzle passage and the valve chamber for cooperating with the' valve when in its idle position, whereby whenever the valve moves from normal operating position to idle position, the nozzle 65v passage is sealed from the valve chamber after rst being reverse flushed with air. A

5. In an apparatus of the character described for discharging a mixture of a liquid and a gaseous fluid, a nozzle having an orifice, a liquid supply passage leading to said nozzle,. means operable intermittently to supply liquid to said liquid supply passage, a valve chamber in communication with said liquid supply passage, a valve located between said chamber and the nozzle to cut otr said orifice from said liquid supl ms e 1o ply passage. means to move said valve to said REFERENCES CITED cut'o position automatically with time del The following references are of record in the after said intermittent means oeases to operate. and means to force air through said valve for me f this tent ushing of the valve after the intermittent means 5 UNITED STATES PATENTS ceases to operate and before the valve moves to Number Name Date its cut-oil' position, said last named means in- 1.652.710 Domi-weich M 13, 1927 cluding a low pressure bi1-pass port communicat- 1707'340 Young APL 2, 1929 ing With Said We chmbel'- lo 1,716,325 Rogers June 4, 1929 2,199,454 Andler et al. May 7, 1940 EARL JOSEPH SENNINGER. 22061957 Hose July 9, 1940 2,397.9@ sennmger Apr. 9, 194s-

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