US2313298A - Atomizer - Google Patents

Description

March 9, 1943. K. 1.. MARTIN EIVAL ATOMIZER 2 Sheets-Sheet 2 Filed March 3, 1939 IN VENTORS.

A TTORNE Y.

Patented Mar. 9, 1943 ATOMIZER Kingsley L. Martin, Montclair, N. J., and Edward A. Holden, Jamaica, N. Y.

Application March 3, 1939,'Serial No. 259,558

15 (Claims.

This invention relates to mechanical pressure atomizers for burning oil, for enriching gas in carburetors used in the manufacture of water gas, and for other purposes where it is desired to obtain a finely atomized mist-like spray at a reasonably low pressure and having a wide range in capacity.

More particularly our invention relates to atomizers of the type provided with an atomizer head supplied from primary and secondary sources of oil supply through a plurality of slots or channels preferably with their center lines in a plane transverse to the center line of the whirling chamber, their outer ends being connected to the high pressure or primary source of supply and to'the low pressure or secondary source of supply respectively, and their inner ends terminating in the sides of the whirling chamber in the atomizer head and preferably tangent thereto, the whirling chamber being provided with an outlet orifice through its outer or atomizer end.

Devices of this character heretofore constructed have been subject to many defects, among which may be mentioned the fact that they do not permit regulation throughout a wide range while maintaining the necessary rotational velocity of the oil in the whirling chamber to properly atomize the oil, and the construction of the atomizer heads is such as to cause carbonization of the oil in passages temporarily shut off for purposes of regulation, due to the radiant heat from the burner being transmitted through the metal of the head to the oil in the idle passages. These and many other defects in prior devices have been overcome by our invention, as will hereinafter more fully appear.

The primary purpose of our invention is to maintain at all times the necessary rotational velocity of all the oil in the whirling chamber so that the oil emerging through the discharge orifice will be properly atomized. To this end the primary source is caused to operate continuously at a relatively high pressure through small individual passages, so as to maintain the highest entering velocity into the whirling chamber, the primary slots being advantageously narrow and tapered towards their inner ends to effect this result. The secondary oil is advantageously conducted into the whirling chamber through lndir vidual slots separate from the primary slots so that the flow is not merged with oil from the primary source, which may be flowing at a diiierent velocity, until the whirling chamber is reached. The secondary slots enter the whirling chamber either in the same plane or in a plane parallel to the primary slots so that the two velocities will be smoothly combined in the whirling chamber. We have found that the slots in which the primary and secondary oils enter may advantageously lie, respectively, in different but parallel planes, with the high velocity or primary oil entering between the secondary ports and the discharge orifice. This is advantageous, since, when both sources are in use, the spin from the primary jets which is purposely maintained at a high velocity is added to that already imparted to the secondary oil by its passage through its own tangential slots or channels. When the secondary oil is not flowing, the primary oil has the upper part or the whirling chamber near the orifice in which to maintain its own rotation. This arrangement has the further advantage that when the oil is caused to enter at reducedpressure through the primary slots and surplus oil is being led away through the secondary slots, as contemplated in one stage of our operation, the oil is withdrawn from the bottom of the whirling mass of oil in the chamber and the smooth spiral flow of the oil from the primary slots to the discharge orifice is not disturbed. This construction also permits the flow in the whirling'chamber to be smooth and continuous, as there are no holes or other obstructions in the floor of the chamber which would interfere with the smooth flow of oil around the whirling chamber.

It is a further purpose of our invention to so construct the burner head and to so arrange the flow of oil through it as to dissipate :and carry 01? the metal heat imparted by radiant heat from the burner which would otherwise carbonize the oil in the idle passageways. To this end the passages for the primary and secondary oil through the burner head are made substantially larger than the tangential slots or channels so as to be of sufllcient volume to prevent harmful carbonization in the passages and substantially the whole inside of the sprayer plate, which is made separate from the atomizer head or body proper is filled with rapidly flowing oil which prevents the oil in the designedly short tangential slots carbonizing. This results from the fact that we introduce both the primary and the secondary 011 near the outer periphery of the sprayer plate and from this point pass the oil inwardly across substantially the entire area of said plate into the whirling chamber which is of relatively large size, this peing permitted by the fact that both the primary and secondary oil are introduced near the periphery of the sprayer plate and not one inside the other as in some previous constructions.

It is a further purpose of our invention to provide for reversal at times of fiow through one source so .as to obtain the combined advantages of both the dual supply and no return method, as well as those of the single supply and single return method of securing wide range capacity.

In other words, after all the possibilities of dual secondly reducing the primary pressure and flow to its lowest limit, a still further reduction is obtained by bleeding oil from the whirling chamber through the secondary passages.

While still maintaining primary pressure and I flow through tangential slots at or near it minimum, a very effective action in our device is obtained by putting the bleed ports in the vertical side walls of the whirling chamber so as to utilize the pressure caused by the centrifugal force of the whirling oil to exert an initial pressure to start the oil through the return system.

Our device differs from all others in that we use the high velocity primary oil to supplement the, at times, low velocity secondary oil rotation,

hereinbefore described is made by utilizing acentral metal cone or spindle in the whirling chamber in combination with the primary and secondary tangential slots herein described, particularly when the slots are in different planes. The advantages of the spindle in the usual atomizer having tangential slots of uniform size through which all the fluid is forced at the same pressure, are disclosed in Patent No. 2,044,091, issued to Kingsley L. Martin on June 16, 1936. Its further advantages, when used with the primary and secondary tangential slot arrangement supplied with fluid from a dual source, as herein described, are: (a) Increase in maximum capacity of the atomizer with the same fluid pressure and the same size orifice; (b) a lowering of the minimum pressure at which satisfactory atomization can be obtained with fluid from the primary source only; a-much smaller quantity of fluid to be kept in rotation in the whirling chamber; (d) a more effective action of the primary supply jets in accelerating the rotation of the fluid from the lower secondary supply Jets as it flows in a spiral path toward the orifice past the openings through which the primary fluid enters the whirling chamber; is) elimination of eddy currents in the base of the whirling chamber when fluid is being bled therefrom; and (I) elimination of cavitation in the base of the rotating fluid in the whirling chamber.

Other novel features and advantages of our invention will hereinafter appear.

Referring to the accompanying drawings,-

which form a part of the specification in which like numerals designate like parts in all the views and which show, for purposes of exempliflcation, certain preferred embodiments of our invention, but without limiting the scope of our invention or claims thereto:

Fig. 1 is a central longitudinal section through one form of atomizer showing the primary and secondary connections thereto. Fig. 2 is a central longitudinal section of the atomizer body on line IIII of Fig. 3. Fig. 3 is an end view of the atomizer body. Fig. 4 is a bottom view of a sprayer plate having the primary and secondary tangential slots in the same plane. Fig. 5 is a central longitudinal section of sprayer plate on the line .VV of Fig. 4. Fig. 6 is a central longitudinal section of an atomizer nut. Fig. '7 is a longitudinal section of the atomizer body as in Fig. 2 with the nut of Fig. 6 applied thereto. Fig. 8 is a bottom view of a sprayer plate having the primary and secondary tangential slots in different planes. Fig. 9 is a cross-section of this 'plate on the line IX-IX of Fig. 8. Figs. 10, 1 1

and12 are flow diagrams showing direction and path of flow of primary and secondary fluids under various operating conditions, the primary and secondary slots being of different sizes respectively. Figs. 13 and 14 are fragmentary sectional views on the lines XIIIX[II and XIVXIV, respectively, of Fig. 8. Fig. 15 is a longitudinal section of a modified form .of the atomizer body of Fig. 7 showing detail of central cone or spindle. Fig. 16 is an end view of the atomizer body shown in Fig. 15.

Referring to the drawings, I is a pipe having screw threads 2 and bore 3. The atomizer body 4 is threaded on pipe I. A second pipe 5 with bore 6 and screw threads I is located concentric with pipe I, leaving an annular space 8 between the two pipes. The pipe 5 is threaded into an inwardly projecting cylindrical extension 4 of the body 4, said extension being surrounded by an annular space 8' forming an extension of the annular space 8. From the annular space I a series of passages 9 lead outward to the face II of the atomizer body. The provision of the annular space 9' materially shortens the length of the passages 9, thereby minimizingtheir liability to carbonization. From the chamber I2 at the end of the inner pipe 9 a series of passages II lead outward to the face III of the atomizer body 4. One arrangement of the passages 9 and I I and their outlet in the face III of the atomizer body 4 is shown in Fig. 3 where the passages 9 leading from the outer pipe I connect with tangential slots alternating with those connecting with passages II leading from the inner pipe 5. The passages 9 and II are preferably made larger than the tangential slots to minimize harmful carbonization therein.

The sprayer plate I3 is clamped securely to the burner body 4 by the atomizer nut I4, which has screw threads I5 which engage similar threads on atomizer body 4. The sprayer plate I3 is shown more fully in bottom plan and longitudinal section in Figs. 4, 5, 8, and 9. The fluid to be atomized enters the whirling chamber I6 through tangential slots I1 and 25, and leaves it through the orifice I8.

The sprayer plate I3 is held central by the shoulders I9 and 29 and against the body face III to form a liquid-tight seal by the shoulder 2I, It is held so as to give the correct relative position of holes 9 and I I to tangential slots I1 and 25 "by pins 22 located, say, on the body 4 and seating in corresponding recesses or holes 22' in the sprayer plate.

The central cone or spindle 28 may be modifled in shape and its position relative to the orifice may be changed to get different useful results.

In atomizers heretofore generally used, the fluid to be atomized is introduced through tangential slots somewhat similar to those shown, but under uniform pressure in all the slots, and rotated at high velocity in the whirling chamber.

The liquid then, when under high pressure, has

the velocity of rotation which is essential to fine atomization and also has a velocity of translation parallel to the central axis of the orifice. which is necessary to secure the discharge of the desired amount of the fluid being atomized.

There are in use three principal methods of securing a wide range of capacity while maintaining flne atomization. The first and most generally used employs only one pipe similar to I, Fig. 1, and decreases the liquid pressure as much as may be necessary to insure the discharge of the required amount of liquid. This method has the disadvantage of lowering the velocity of flow through the tangential' slots, which, in turn, diminishes the velocity of rotation of the liquid in the whirling chamber. Consequently, the centrifugal force imparted to the liquid leaving the orifice is decreased and the I atomization rapidly loses its fineness and mistlike quality.

The second method has been to use two concentric pipes similar to i and 5, one supplying fluid under constant and high pressure through tangential slots to a whirling chamber. Instead, however, of discharging all of the fluid supplied to the burner through the orifice, all that part not required at the moment is drained from the whirling chamber by means of the second pipe and returned to storage tanks or to pump suction. The quantity atomized is usually controlled by a valve on the return line. This method is open to the objections (a) that substantially the maximum'quantity of fluid ever required must be continuously raised to atomizing pressure and delivered to the atomizers; (b) if heating is necessary to reduce the viscosity of the fluid, as is the case with fuel oils, then this maximum quantity of liquid must also be heated to atomizing temperature, which in the case of fuel oils is usually above the flash point; and (c) if not required at the moment, this fluid, which has been raised to high pressure and usually to high temperature, must be returned to the system at a reduced pressure and disposed of in some manner.

The third method is to divide the fluid at a point outside of the atomizer and by use of concentric pipes and separate passages through the atomizer body introduce the fluid tangentially into the whirling chamber to be entirely discharged through an orifice, no fluid being returned to the source. V

The method we have adopted is a combination of dual supply connected to the whirling chamber by independent passages and at times a re- I turn for surplus fluid with essential improvements in construction and methods used to supply to, and at times return fluid from, the whirling chamber in order to overcome operating difficulties experienced with other systems.

In our system the fluid, while coming from the source of supply and. before entering the atomizer, is divided through valved connections A and B respectively (Fig. 1) into two streams, one of which, the primary fluid, is maintained at a high pressure and the other stream, called the secondary, varies in pressure and flow from the maximum to zero. The function of the primary stream is to maintain in the whirling chamber at all times a high rotational velocity of the fluid to insure its proper atomization when issuing-from the discharge orifice. One of the functions of the secondary stream is to supply suflicient fluid to make up, with that supplied by the primary, the total amount of fluid required for discharge from the orifice and, insofar as its generally lower velocity permits, aid the primary in maintaining the essential rotational velocity. Another function of the secondary system is to provide, by reversal of flow from the whirling chamber through the tangential grooves to which it is connected, for the removal of a part of the fluid supplied by the primary when operating at low capacities and which is not needed at the moment. By this method, suillcient fluid is forced through the primary slots to maintain the entering and rotational velocity necessary for the atomization of the fluid, this amount being at times greater than that required for discharge from the oriflce, and the surplus is bled from the whirling chamber in such a way as not to affect the rotation of the fluid in the chamber.

The atomizer head is so designed and the passageways are so located that no passageways will be obstructed by carbonization of oil lying in and not flowing through them.

. We accomplish these results by feeding the high pressure primary fluid through the tangential slots. 25 at a high velocity to insure .a rapid whirling motion and centrifugal force to all fluid in the whirling chamber l6. This fluid will be,

in part, the primary fluid supplemented by the secondary supply introduced to the whirling chamber l6 throughthe remaining slots l'l, independently of and alternating with the primary slots 25.

This method is preferred because at the highest capacity both primary supply in pipe I and secondary supply in pipe 5- will be under the maximum fluid pressure available and each stream will have full velocity and will perform its own part in developing centrifugal force in the whirling chamber 16.

To reduce capacity, the pressure of only the secondary fluid in supply pipe 5 is gradually reduced, leaving the primary in supply pipe I at full pressure and velocity, so as to maintain in the whirling chamber IS, in conjunction with the residual velocity of the incoming secondary fluid, suillcient centrifugal force to atomize the reduced total quantity. i When the pressure and flow of the secondary fluid in supply pipe 5 has been reduced to zero,

this completes the first stage in capacity reduc- In the second stage, the pressure of the I tion. primary fluid in supply pipe I is reduced as low as permissible with the maintenance of good atomization, following in this respect the first principal method now used to reduce capacity hereinbefore described.

It will be noted that when the secondary fluid in supply pipe 5 has its lowest input and, therefore, lowest tangential velocity, it also has its smallest quantity, making it possible for the highpressure and high-velocity fluid to add the necessary whirling action to insure good atomization.

Conversely, as the quantity of secondary fluid is increased, its tangential velocity isincreased until it is substantially equal to and independent of the primary fluid.

Another very important advantage peculiar to this method is the maintenance of the correct slots 25 in use for primary fluid may be only an fraction of the orifice area. It has been found by years of experience that the lower ratio is very desirable for small capacities and that a much larger ratio is not only permissible but de-' sirable at very high capacities.

A third stage in reduction of capacity is made by utilizing the slots l1 and pipe 5 heretofore described as supplying secondary fluid to the whirling chamber as a bleed line to extract fluid introduced to the whirling chamber through the primary supply line 8, 9, and 25, and not needed at the moment. This bleeding may be used after the reduction of primary fluid pressure mentioned in describing the first stage reduction or it may be used without said reduction, depending on operating conditions.

While the reduction of capacity is described as being in stages, it should be understood that the action is not step by step, but a gradual and smooth reduction in flow of atomized fluid from the orifice.

It is important that the extraction of surplus fluid from the whirling chamber be effected without interfering with the rapid rotation of the fluid or establishing eddy currents. To this end the tangential grooves are preferably arranged in two planes, the primary fluid from supply pipe I entering the whirling chamber l6 through tangential slots 25 which are between the tangential s'lots I! through which the secondary fluid from supply pipe 5 is, at higher capacities withdrawn from the whirling chamber. As the fluid is withdrawn from the base of the whirling cone of fluid, its rotation is not disturbed.

The action is clearly shown in flow diagrams Figs. 10, 11, and 12. During the first stage, shown in Fig. 10, the primary fluid enters at constant high pressure through the slots 25 which, as shown in Fig. 10, are preferably of smaller capacity than the slots I! through which the secondary fluid is delivered or through which part of the fluid is at times bled from the whirling chamber l6. This difference in slot size is to insure a high entering velocity of the primary fluid so as to impart by impact sufficient rotational velocity to the mass of oil in the whirling chamber. During the first stage the pressure of the secondary fluid in slots I! is gradually reduced until flow ceases and the quantity discharged from the oriflce l8 becomes that delivered through slots 25 only.

During the second stage, shown in Fig. 11, .the flow of secondary fluid through slots l1 remains shut off and the pressure of the primary fluid flowing through slots 25 is gradually reduced to the allowable minimum that will produce satisfactory atomization of the reduced quantity of fluid.

During the third stage, shown in Fig. 12, all the fluid to be atomized enters the whirling chamber I6 through the passages 9 and primary slots 25. As much as is required at the time is discharged in atomized form through the orifice l8 while the remainder is bled back to the storage system through the slots l1 and passages I l. The centrifugal force necessary for fine atomization is maintained in spite of the reduced orifice discharge (a) by continuing to force sufilcient fluid through the primary slots 25 to secure the necessary velocity and (b) by bleeding the surplus fluid from the whirling fluid in such a manner as not to diminish the velocity of rotation below that required to give satisfactory atomization.

The tangential slots used for the primary supply may, in size and number, be equal to or different from the slots used for the secondary supply.

The advantages of this method of securing a wide range of capacity while retaining through a sufficiently fine atomization are:

1. For the first and second stages, only the quantity of fluid to be atomized at the moment need be pumped to the atomizer so that the rais ing of a surplus amount, which is returned in some systems, to atomizing pressure and, in the case of fuel oils, to viscosity temperature, is obviated. During the third stage, only a ,very small portion of the greatly reduced amount of fluid which is being supplied to the atomizer through the primary passages only, is returned and constitutes a very small portion of the maximum capacity of the atomizer. With other systems, the proportion of hot oil returned may be, and frequently is, a very large proportion of the amount of oil required to operate the atomizer at its maximum capacity.

2. The size and cost of valves and piping in the return line is materially decreased and the difliculties in disposing of the small quantity of hot oil returned under our system becomes negligible.

3. The method lends itself to automatic control of either an individual atomizer or of a group of atomizers, as the two sources of supply may be independently controlled either (a) simultaneously for all atomizers; or (b) the primary supply may, if properly proportioned to give minimum capacity, be operated at constant high pressure, and the secondary supply only may be automatically or manually controlled so as to furnish sufflcient additional fluid to give the capacity required under any given conditions; or

I or by individual valves at the atomizers. t

It will be understood that vvarious changes may be made in the form, features, and arrangement of the several parts disclosed by way of exemplification without departing from the spirit and scope of our invention, and that certain features may be used to advantage without a corresponding use of other features. We, therefore,

' 'do not wish to be limited to the particular embodiments disclosed.

We claim:

1. In an atomizer, a whirling chamber, two sets of tangential channels leading thereto in the same circumferential direction; dual means for supplying, respectively, to the respective sets of tangential channels, fuel to be atomized thereby in said whirling chamber; and regulatable means for converting one of said supply means into means for withdrawing from said whirling chamber, through the corresponding set .of tangential channels, a controllable portion of the fuel supplied to said chamber by the other of said supply means through its correesponding set of tangential channels.

2. The combination as defined in claim 1 in which the tangential channels through which the fuel is supplied to the whirling chamber are located in a plane between that in which the channels through which the fuel is withdrawn from the whirling chamber are located and the orifice through which the remainder of the fuel is discharged and atomized.

3. In an atomizer, a whirling chamber, means for sub-dividing fuel to be atomized into two streams separately but in the same direction of whirl into said whirling chamber, reducing the pressure in one, only, of said streams gradually to zero, then gradually reducing the pressure in the other of said streams, and thereafter withdrawing'from said chamber a portion of the fuel fed thereto by said other stream.

5. In an atomizer, atomizing means for connection to a dual source of supply of a fuel to be atomized, said means being provided with a central whirling chamber with an outlet orifice at itsouter end, and having at its base a plurality of channels with their center lines in av plane transverse to the center line of the whirling chamber, the outer ends of some of. the channels being adapted for connection to one source of supply and the outer ends of others of the channels being adapted for connection to the other source of supply, and.the inner ends of the channels terminating in the sides of said -whirling chamber, said channels lying substantially tangent to the side walls of said whirling chamber, and in the same circumferential direction, and means for connecting one of said set of channels into means for withdrawing from said chamber a portion of the fuel fed thereto 'by the other set of channels.

6. In an atomizer, atomizing means for connection to a dual source of supply of a fuel to be atomized, said means being provided with a central whirling chamber with an outlet orifice at its outer end, and having at its base a plurality of channels with their center line transverse to the center line of the whirling chamber, the outer ends of some of the channels being adapted for connection to one source of supply and the outer ends of others of the channels being adapted for connection to the other source of supply, and the inner ends of the channels terminating in the sides of said whirling chamber, said channels lying ubstantially tangent to the side walls of said'whirling chamber and in' the same circumferential direction, and means for converting oneof said sets of channels and their connections into means for withdrawing from said chamber a portion of the fuel fed thereto by the other set of channels.

7. The combination as defined in claim 6, in which said respective sets of channels are located in difierent planes.

8. The combination as defined in claim 6, in which said respective sets of channels are located in difi'erent planes and in which the convertible set of channels is more remote from the orifice than the other set.

9. In an atomizer, atomizing means for connection to a dual source of supply a fuel to be atomized, said means being provided with a central whirling chamber with an orifice at its outer the base of the whirling chamber toward the.

orifice and having at its base a plurality of channels with their center lines transverse to the center line of the whirling chamber, the outer ends of some of the channels being adapted for'connecticn to one source of supply and the outer ends of others of the channels being adapted for connection to the other source of supply, and the inner ends of both sets of channels terminating in the sides of said whirling chamber and lying substantially tangent to the side walls of said whirling chamber and in the same circumferential direction.

10. In an atomizer, atomizing means for connection respectively to primary and to secondary sources of supply of a fuel to be atomized, said means being providedwith a central whirling chamber and an outlet orifice leading therefrom, anda plurality of channels the outer ends of some of which are adapted for connection to the primary source of supply and the outer ends of the others of which are adapted for connection to the secondary source of supply, the inner ends of all the channels terminating in said whirling chamber, the channels which are connected to the primary supply lying between the channels connected. to the secondary supply and the orifice, and means for disconnecting said other channels from the secondary source of supply and connecting them for withdrawal of fuel from said chamber.

11. The combination as defined in claim 10 in which the primary channels are relativelymarrow as compared with the secondary channels,

12. The combination as defined in claim 9, in which said respective sets of channels are located in different planes.

13. The method of operating an atomizer comprising a whirling chamber which method comprises establishing two streams offuel thereto one of relatively small cross-sectional area and the other of larger cross-sectional area, introducing said streams separately into said whirling chamber, reducing the pressure of the stream of larger cross-sectional area gradually to zero and then gradually reducing the pressure in the other of said streams.

14. The method of operating an atomizer comprising a whirling chamber which method comprises establishing two streams of fuel thereto one of relatively small cross-sectional area and theother of larger cross-sectional area, introducing said streams separately into said whirling chamber, reducing the pressure of the stream of larger cross-sectional area gradually. to zero, then gradually reducing the pressure in the other of said streams and thereafter withdrawing from said chamber a portion of the fuel fed thereto by said other stream.

15. The combination as defined in claim 9 in which said respective sets of channels are located in different planes and in which means is provided for converting one set of channels and its connections into means for withdrawing from said chamber a portion of the fuel fedthereto by said other set of channels, said one set of channels being more remote from the orifice than said other set of channels.

KINGSLEY L. MARTIN. EDWARD A. HOLDEN.

Images