US2416685A - Atomizer - Google Patents

Description

March 4, 1947. J. FLETCHER ATOM I Z ER 3 Sheets-Sheet 1 Filed March l, 1941 mvmox James Fletcher mm .I N um Q NN A torney Mllth 4, 1947. 1 FLETCHER 2,416,685

ATOMIZER y Filed March 1, 1941 3 Sheets-Sheet 2 124 A fr f I v 130 y 1 Mgr/36 1 1* fig- 6 HO/y\ \w// ,UMH/11% l "8 126 11AM, 118i 134 ,-`r f' 116 E, I2C fr. n y 10S/4^ 122 \V///// 147/ 12o A 104 103 \,34 1oz z 131i 106 INVENTOR James Fletcher BY Mm@ March 4, 1947. J. FLETCHER ATOMIZER Filed March l, 1941 3 Sheets-Sheet 3 .www 4 INVENTOR a/'azzzes/zfecer ATTORNEY Patented Mar. 4, 1947 ATOMIZER James Fletcher, Akron, Ohio, assigner to The Babcock & Wilcox Company, Newark, N. J., a corporation of New Jersey Application March 1, 1941, Serial No. 381,217

12 Claims. l

The subject of this invention ls an atomizer and its associated controls especially adapted for use in a burner for liquid fuel whereby an acceptable quality of atomization may be maintained over an extended range of capacities for optimum combustion characteristics. The atomizer is broadly of the mechanical type in which a liquid under pressure is sprayed from an orice under the influence of centrifugal force, the atomized uid being discharged from the orice in the form of a cone.

An object of the invention is to provide a mechanical atomizer operable at different flow capacities and capable of producing a spray of eilicient combustion characteristics throughout the entire capacity range. A related object is to achieve such operation without alteration. in the structure of individual atomizer components.

An additional object is to provide a gradation of capacities subject to an adjustment of atomizer parts, or to an adjustment of the pressure at which the liquid to be atomized is supplied; or, if desired, to a combination of such adjustments. The adjustment of atomizer parts is intended prl marily to make available at different capacities a different ow area of passages through which the uid is directed to impart the degree of rotational velocity necessary for satisfactory atomization. It is contemplated that the adjustment of flow area may be effected manually, or preferably 'by automatic means subject to a pressure characteristic of the liquid supply. The latter method, particularly in the case of a burner, may include the regulation of the supply pressure in automatic relation to a demand for fuel, as indicated by an operating characteristic of the heat-receiving apparatus with which the burner may be associated.

Another object is to maintain as nearly as possible a substantially constant divergence of spray throughout an extended capacity range, the general tendency in atomizers of the mechanical type being to spray liquid at a relatively Wide angle at low capacities and at a relatively narrow angle at high capacities.

Other objects of the invention pertain to the incorporation of an atomizer in a burner assembly providing automatic control of the atomizer operation, the parts being so constructed and arranged as to facilitate assembly and disassembly and to permit ready access for inspection or replacement.

The various objects and advantages of the invention, and the means whereby such objects may be achieved, are more fully disclosed in the description which follows, and in the accompanying drawings, wherein:

Fig. 1 illustrates, in longitudinal section, an embodiment of the invention in a burner;

Fig. 2 is an enlarged fragment of Fig. 1 showing the relation of parts adjacent the spray orifice;

Fig. 3 is a transverse section of Fig. 2 along line 3-3;

Fig. 4 is a diagram illustrating a detail of Fig. 2;

Fig. 5 is a fragmentary longitudinal section showing a modiflcation;

Fig. 6 is a transverse section of Fig. 5 along line 6 6;

Fig. '7 is an assembly in longitudinal section, incorporating the elements of Fig. 5;

Fig. 8 is an assembly in section indicating a modification of parts shown ln Fig. 7;

Fig. 9 shows a modiiication of atomizer components in longitudinal section;

Fig. 10 is a section of Fig. 9 along line l0-Ill;

Fig. 11 is a modification of the operating mechanism of Fig. 1; and

Fig. 12 is a modified assembly, similar to Fig. 1, incorporating the atomizer structure shown in Figs. 5 and 7.

In detail, and referring particularly to Figs. 1, 2 and 3, the atomizer assembly I0 may be mounted within a hollow distance piece I2 which carries an impeller plate I4 for providing an intimate mixture of combustion air with the atomized fuel issuing from the orifice I6. An atomizer coupling I8 is secured to the distance piece I2 as by threads 20 to provide longitudinal adjustment of the atomizer relative to the impeller plate, the desired adjustment being maintained by set-screw 22. A collar 24 including the inner packing ring 26 prevents leakage of air through the annular space 28 between the barrel 30 of the atomizer and the distance piece I2; the collar being held in contact with the coupling face 32 by means of the spring 34 which is seated against the shoulder sur I face 36 on the atomizer body 38; the packing ring `2li bearing against the outer surface of the barrel 30 which may be removably secured to the atomizer body as by threads 40.

Fuel is supplied to the atomizer through a pipe connection 42 which leads from a suitable source (not shown) of liquid fuel under pressure, the fuel entering through the coupling passage 44 and flowing through the body passage 46 to the interior body space 48. The joint 50 between the body and coupling is maintained pressure-tight by means of a quick-detachable clamping device comprising the yoke 52 which is hinged to the coupling at 54 and carries a bolt 56 which may be screwed against the body as at 58. A valve in the connection 42, for controlling the pressure Y 3 and quantity of fuel admitted to the atomizer, may be of a manually operated type as shown, or of a suitable automatic type, as may be determined by requirements of the installation.

The barrel 30 is fitted with a sprayer plate 62 at its forward end to provide the cylindrical orice passage I6 from which fuel is discharged in a fine mist or spray of hollow conical formation, the orifice plate being conveniently held in position by an internally threaded cap 64 which clamps the circumferential flange 66 against the end of the barrel. The plate is preferably formed with a hollow cylindrical extension or collar to provide a recess or whirl chamber 10 of circular cross-section having its outlet in the axially adiacent oriiice IB from which atomized fuel is discharged, the interior wall surface of the recess including a conical portion 12 having its apex preferably within the orifice I6 and a cylindrical portion 14 for the remainder of its length, the cylindrical surface portion being annularly grooved as at 'I6 to approximately the maximum diameter of the conical surface portion.

Fuel is admitted to the chamber 10 through a series of passages or ports 18 which extend through the cylindrical extension 68 in a direction generally tangent to the inner wall surface 14 and preferably in planes normal to the common longitudinal axis. The port area available for ow of fuel into the whirl chamber is regulated by the axial movement of a plunger 80 which is actuated in accordance with the movement of an operating spindle 82 extending longitudinally of the barrel 30 and spaced inwardly of the barrel to provide the annular space 84 for fuel ow from the interior body space 48gto the region 86 surrounding the tangential ports 18.

In the form shown, the plunger 80 is made an integral part of the operating spindle and being:

of a smaller diameter than the spindle provides a shoulder 83 which when moved into contact with the end of the sprayer plate extension 60 limits the forward movement of the plunger 00 and determines the minimum limit of fuel port area open to the chamber 10, The plunger may be annularly grooved as at 90 to enable the shoulder 88 to be seated rmly against the extension 68 to permit close adherence to a predetermined minimum capacity setting. A movement of the plunger to the rear of the recess, that is, toward the right as seen in Fig. 2, will increase the area l available for fuel ow into the chamber by uncovering a greater area of the same port or ports, or by uncovering additional ports, at successive longitudinal positions.

A selected arrangement of ports 18 is indicated lin Fig. 4 by a diagrammatic development of the inner cylindrical surface 'I4 which is slidably engaged by the plunger 80, the ports being disposed l in nine successive transverse planes A, B, C, etc., and being directed tangentially of the chamber in four tangential planes R, S, T and U, each i tangential plane being displaced substantially 90 from the one circumferentially adjacent. Each transverse and preferably normal plane A, B, C, etc., contains two ports 180 apart, and in alternate transverse planes the ports are in parallel `tangential planes to enter the chamber at diametrically opposite locations; for example, in one group of alternate planes A, C, E, G, and L, the ports are in parallel tangential planes such as R and T; and in the remaining group of alternate planes B, D, F, and H, the ports are in parallel tangential planes S and U.

In the illustrated arrangement, the ports $2 in minimum fuel flow area for low capacity operation. In this position all other ports are blocked oi including the ports 96 in the adjacent plane B since there is a definite longitudinal spacing between the perimeters of ports 92 and ports 90 as indicated by the dimensional arrows M-M. As the plunger is moved away from the orifice, and the plunger face 94 reaches plane B at the center of ports 90, or a position slightly beyond plane B, the ports 98 in plane C are gradually uncovered along with the remaining portions of ports 96 in plane B. Thus, the ports in adjacent planes B and C, C and D, etc., overlap longitudinally to the extent indicated by the arrows N-N in order to maintain a progressive and substantially uniform variation in port area exposure for successive positions of the plunger. It will be noted that the variation in port area is accompanied by a variation in the depth of the whirl chamber, due to the different positions assumed by the plunger face 94 which forms the base of the chamber.

Fig. 5 shows a modified arrangement of whirl chamber and plunger wherein the whirl chamber |00 is of a fixed axial dimension and the plunger |02 includes a hollow extension or sleeve portion |03 which telescopes exteriorly with the sprayer head |04 to regulate the port area available for fuel ow into the chamber. The whirl chamber |00 is cylindrically formed throughout to include the cylindrical recess |06 within the sprayer head and the cylindrical recess |08 within the sprayer plate ||0, the base ||2 of the chamber being normal to the axis and imperforate, while the opposite end wall ||4 which is also normal to the axis, provides the entrance to the cylindrical outlet orice IIB in the sprayer plate IIO. In this arrangement a single port is disposed in each of the transverse planes A, B, C, D, E and F, and in each plane the port is directed tangentially of the whirl chamber as indicated in Fig. 6; the ports IIB in the transverse planes A and D lying in the tangential plane X, the ports |20 in planes B and E lying in plane Y, and the ports |22 in planes C and F lying in plane Z. The circumferential spacing of successive tangential planes X; Y, Z is approximately The longitudinal spacing of the transverse planes A to F, and the diameters of the ports H8, 20, |22 in those planes, are preferably so selected as to provide a longitudinal clearance between the perimeters of ports ||8 and |20 in planes A and B corresponding to the dimension M-M in Fig. 4; also, to provide an overlap corresponding to the dimension N-N between ports |20 and |22 in planes B and C, and between similarly adjacent ports in the succeeding planes D, E and F. Thus, port H8 in plane A may be fully uncovered without exposing any portion of port |20 in the adjacent plane B, when for example, for minimum capacity, the forward edge |24 of the plunger |02 is advanced to the position shown in Fig. 5; and, as the plunger is retracted, for increasing capacities, to approximately the center line of a port such as 20 in plane B, the nexty succeeding port such as |22 in plane C is about to be exposed, and so on throughout the series in a manner similar to that described in connection with Fig. 4.

'Ihe extreme forward position of the spindle |26 is fixed by means to be described hereinafter and since the plunger and spindle are connected as at |28, the extreme position to which the plunger may be advanced is also determined and thereby the amount of port area available at the minimum capacity setting. An adjustment may be made however to provide a greater or lesser minimum value of exposed port area, by screwing or unscrewing the plunger relative to the spindle at the threaded connection |28 and maintaining the adjusted relation of the parts by means of the hollow lock nut |30.

Comparing the forms shown in Figs. 2 and 5, where in one case the plunger is reciprocable interiorly of a ported element 68 and in the other exteriorly of a ported element |04, it will be noted that the ports are arranged in a different number of transverse planes A, B, C, etc., and that the number and circumferential spacings of the ports in such planes are different. In addition to detail variations of this general character, it is contemplated that other variations may be made within the scope of this invention to include forl example variations in the size and form of the ports, variations in the longitudinal spacing of the ports, and variations in the angle relative to the longitudinal axis at which the ports are directed tangentially of the whirl chamber; the factors governing such permissible variations including the total range of port area required within the range of plunger movement, and the rate of port area variation for different capacities in relation to the rate of plunger movement.

Fig. 7 shows an assembly of the elements of 4 Fig. 5 within the burner barrel 30, the sprayer plate being centered with respect to the sprayer head by dowels |32 and the parts being maintained in their assembled relation at the end of the barrel by cap 64. Fuel under pressure flows through the annular barrel space 84, as in Fig. 1, to the annular space 86 adjacent the entrances to the tangential ports in the successive transverse planes A to F; the extent to which such ports are uncovered for flow of fuel into the whirl chamber |00 being regulated by the longitudinal movement of the hollow plunger |02 which is actuated by spindle |26, as already described. One or more holes |34 extend through the wall of the plunger sleeve |03 from the outer space 86 to the inner space |36 at the rear of the sprayer head |04, to maintain a balance of pressures conducive to normal operation of the plunger.

In Fig. 8, as in Figs. 5 and '7, the regulation of tangential port area is effected by the reciprocation of a plunger |38 relative to the sprayer head |04, the hollow extension or sleeve portion |40 of the plunger telescoping with the circumferential wall of the whirl chamber |00 and the base surface |42 within the sleeve abutting the end of the sprayer head in the fully advanced position of the plunger to provide a minimum capacity setting. The tangential ports such as |44 may conveniently be of such dimensions and arrangement as to provide full exposure of at least one port at the minimum setting and to provide an overlapping relation between ports at successive longitudinal locations. The plunger may be adjustably connected to the spindle |26 as at |28 and secured in position by lock nut |3l,

An orifice plate |46 is positioned inwardly of the sprayer plate ||0 to provide an inner' orice |48 which may be spaced axially from the outer orifice ||6 an amount eoual to the depth of the sprayer plate recess |08. The combination of a plurality of orifices as shown enables a more sharply defined angle of spray to be maintained at minimum capacity than with the single .orliice I6; the effect being to minimize irregular dispersion of fuel particles outside of the definite angle of cone formation, and thereby eliminate the possibility of carbon being formed on the burner or furnace wall as a result of the impingement of such particles. The relative areas of the inner and outer orices are preferably determined in accordance with the capacity at which the atomizer is to be operated; for example, for a unit having a maximum capacity rating of 3000 lbs. of oil per hour the areas of both orifices may be equal whereas for a 2000 lb. unit the ratio of inner orifice area to outer orifice area may be 11/2:1, and for a 1000 lb. unit 2:1.

Figs. 9 and 10 illustrate a further modification wherein a hollow plunger |50 is movable in telescoping relation with a sprayer head |52 for varying the extent of tangential port area exposed for fluid flow into the whirl chamber |00. A sprayer plate I0 provides the outlet orice H6. The plunger may be suitably connected to an operating spindle |26, and the parts assembled in cooperation with other burner parts, as in Fig. '7 or Fig. 8. In this form the effective port area is increased as the plunger is advanced and decreased as the plunger is retracted; the flange |54 of the sprayer head |52 providing a convenient stop for the front end |56 of the plunger sleeve |58 to determine the extreme position of forward movement when the maximum amount of port area is uncovered, A suitable stop may also be provided to limit the extent to which the plunger may be retracted in order that the effective port area will not be reduced below a predetermined minimum. The ports |60 are shown in a selected substantially balanced arrangement wherein two ports enter the whirl chamber |00 tangentially at each of a succession of longitudinally spaced locations as indicated by the transverse planes |62. The ports at one location may overlap those at an adjacent location somewhat in the manner of Fig. 4. The sleeve |58 is perforated at intervals about its periphery with holes |64 extendingrto the inner circumferential groove |66 which provides an annular space |68 adjacent the entrances to the tangential ports |60. The width of the groove |66 is preferably greater than the width of the circumferential band occupied by the ports to insure that the total area of all ports is exposed when the plunger is in the fully advanced position as indicated in Fig. 9. Fuel entering the holes |64 from barrel space 86 iiows into the an-` nular groove space |68 and from thence into and through the ports |60 into the whirl chamber |00.

Referring again to Fig. 1, the mechanism for causing reciprocation of the spindle and plunger to regulate port area is preferably housed within the atomizer body 38 and constitutes a simple and compact assembly of components readily accessible for inspection and adjustment. A spring |10 exerts a continuous pressure longitudinally of the spindle 82 tending to maintain the plunger in the position of minimum effective port area while a bellows unit |12 subject to pressure of the fuel supply acts in opposition to the spring pressure to move the plunger toward the position of maximum effective port area.

The spindle is formed with an extension |14 having a threaded portion |16 adjacent a shoulder |18 to receive the internally threaded hollow flange member |80 which provides a seat |82 for asiass.

the spring |18 and a rim |64 to which one end of the bellows |86 is connected and sealed. A packing washer |88 seals the joint between the spindle shoulder |18 and the flange member |60 to prevent leakage of pressure from the body space 48 to the interior of the bellows |86. The peripheral ilange |80 on member |80 overlaps the interior body flange |92 in a radial direction to limit the displacement of the spindle 82 and conl bining the sprayer head and plunger assembly of opposite end of bellows |86. The bellows flange |84 is held stationary by the coupling nut 200 which is detachably secured to the body as at 282 and internally threaded as at 288 to receive the adjusting nut 206; the nut 206 having a recess 288 within which the outer end of spring |10 is seated, and an axial bore 2|0 to provide a bearing support and guide for the spindle extension |14. The closure cap 2 I2 is made removable to permit adjustment of spring pressure if desired by means of the adjusting nut 206, and to permit an inspection to be made of the operation of the internal mechanism by noting the travel of the spindle extension |14 within the bore 2|8. Since the longitudinal movement of the spindle and bellows unit is relatively small and may not exceed one quarter of an inch, it is not essential that the space interiorly of the bellows be vented to the atmosphere, the compressive effect on the enclosed air being negligible and in any event subject to correction by means of the spring adjustment. f

A modified form of operating mechanism is shown in Fig. 11 wherein the pressure of fuel within the body space 48 is exerted inwardly of the bellows 2|4. in opposition to the continuous pressure of spring 2|6, to move the spindle 82 and the associated plunger toward the extreme retracted position, whereby, with an arrangement of plunger and sprayer head as in Fig. 1, the effective port area is increased with increased retractive movement of the spindle.

The bellows 2|4 is connected and sealed at its opposite ends to flange members 2|8 and 220 respectively; the flange 2|8, and gasket 222 `if required, being held in place by the bellows nut 224 to form a pressure-tight joint with the body as at 226; and the flange 228 being seated against the spindle shoulder |18 where in conjunction with a suitable gasket it may be held stationary by nut 228 to form a pressure-tight joint.

A spring retainer 238 of cylindrical form surrounds the bellows 2|4 and the bellows flange 228; an inwardly extending flange portion 232 of the retainer loverlapping the outer face ,of flange 220, and an ,outwardly extending flange portion 234 forming a seat for the spring 2| 6. A cage housing 286 having av plurality ,of circumferentially spaced ribs 238 may be adjustably positioned and secured relative to the atomizer body 38 as by threads 240 and locknut 242, and

may be fined with a bushing 24s tcprovide a bearing and guide for the spindle extension |14.

whereby the spring retainer 288 is maintained in contact with the end surface 248 oi the body, and thereby the spindle 82 in the fully advanced position until the pressure oi' fuel within the body and acting interiorly of the bellows is suiiicient to overcome the loading spring pressure. The cage formation of the housing 286 rendersl the working parts of the mechanism visible upon removal of the enclosing shell or cup 250 which is detachably mounted between the lock nut 242 and the end cap 252. As explained in connection with Fig. 1. the relatively short plunger travel makes it unnecessary to specifically provide an atmosphericvent for the enclosed space at the low pressure side of the bellows, in this case, the space exteriorly of bellows 2|4.

Fig. 12 illustrates a further modification com- Figs. 5 and 7 withvthe plunger operating mechanism oi Fig. 1, each of which components has been previously described in detail. Piunger |82 is shown at a position of predetermined minimum capacity where, for example, a single port ||8 is fully exposed for fuel flow into whirl chamber |80. In this position, the peripheral flange |80, fixed in relation to the spindle |26, is in contact with the interior flange |92 on atomizer body 88, the body flange |82 thus serving as a stop to fix the extreme position to which plunger |02 may be advanced during normal operation to insure a, predetermined minimum value of port area exposure. Various values of minimum effective port area may be provided by suitable adjustment of the plunger-to-spindle connection |28.

In the operation of mechanical atomizers of the type described, wherein the leiective iiow area of fuel passagesv may be varied to regulate flow capacity, it is important to eliminate any possibility of the area being reduced to such an extent that `combustion would be interrupted, either through faulty operation or failure of the regulating mechanism. Accordingly, means is a plunger, as' disclosed, a suitable stop is advantageously provided to prevent the plunger being moved to a position where the effective port area would be reduced below a predetermined minimum. Ii the atomizer is to be shut down entirely, it is preferable to cut off the supply of fuel to the atomizer by means of a valve in the fuel supply line under control of the operator.

A desirable method of operating the foregoing atomlzer-s over a wide range of capacities may include the regulation of capacities over a selected portion of the range solely by varying the pressure at whichfthe fuel is supplied, and over another portion of the range by varying the tangential port areas in combination with fuel pressure variations. If desired, the regulation of capacities by pressure alone may be effected over separatedportions of the total capacity range, and the regulation by pressure and port area over an intermediate portion. A pressure loading spring |10, for example, of a suitable selected rate, may be suitably adjusted by means of nut 206 tofmaintain the plunger inthe position oi minimum effective; port area irrespective oi varia'- tions in fuel pressure belowa predetermined pressure limit. In practice,` with an available operating range of fuel pressures from about 50 lbs.

per square inch to about 250 lbs. per square inch l or: .more,vthe spring loadingpressure may be so adjustedas to hold the plunger stationary while fuelv pressure is being increased from the initial value of Yabout 5 0 lbs. to an intermediate value ot about-12ans., of approximately 40% to 60% of where the valving l the maximum available pressure. As pressures are increased above 120 lbs., the force exerted by the bellows unit |12 is sumcient to overcome the spring loading pressure and the plunger is moved to positions of increased port areas. If the setting of the spring is such that the maximum port area is uncovered before the maximum available fuel pressure is utilized, the range of capacity may be further extended solely by additional increases in fuel pressure to the available limit of 250 lbs. or above. The pressure at which plunger movement is initiated may be suitably adjusted for different maximum pressure values; for example, while 120 lbs. may be best adapted for a 250 lb. limit, a, pressure of approximately 150 lbs. might be preferred for a 300 lb. limit.

The preferred method of regulating capacity in a plurality of stages thus utilizes the available fuel pressure to the best advantage in the maintenance of an acceptable quality of atomization throughout a wide range of capacities. If capacity variation were the sole objective, irrespective of the spray characteristics, it would be feasible to utilize the entire pressure range for plunger movement alone and thereby obtain the minimum capacity variation per increment of pressure change. If quality of atomization were the sole consideration, it would be desirable to maintain maximum fuel pressure at all capacities. Therefore, by maintaining a constant and relatively small effective port area for the lower capacity stage at fuel pressures ranging from 50 to 120 lbs., a reasonable pressure for adequate atomization is built up before the effective port area is increased for higher capacities; and, further, as fuel pressures are increased beyond 120 lbs. for the higher capacity stage, where pressure variations are coordinated with variations in effective port area, a reasonable capacity variation is obtained per increment of pressure variation throughout the remainder of the available pressure range.

The coordination of pressure variations with variations in port area also tends to maintain a more nearly uniform angle of spray throughout the entire capacity range.

While the invention has been disclosed more particularly with reference to certain selected embodiments, it is to be understood that the l invention may take other forms, and that certain features of the invention may be applied individually, or in various combinations, within the scope of the appended claims.

I claim:

1. In a liquid atomizer, means forming a whirl chamber having an outlet orifice in an end wall thereof and a series of tangentially directed inlet ports for liquid distributed longitudinally thereof in an enclosing cylindrical wall, means for varying the effective flow area of said ports comprising a plunger telescoping with said first named means and having a valving edge movable forwardly in the direction of said orifice for progressively decreasing the amount of port area effective for the flow of liquid into said chamber, means for moving said plunger including a movable spindle having an axially adjustable connection therewith, and means limiting the forward movement of said spindle and thereby the port area decreasing movement of said valving edge to a position rendering a predetermined amount of said port area continuously effective.

2. In a liquid atomizer, means forming a whirl chamber having an outlet orifice in an end Wall thereof and a series of tangentially directed inlet ports for liquid distributed longitudinally thereof in an enclosing cylindrical wall, and means for varying the effective flow area of said ports comprising a. hollow plunger telescoping exteriorly with said first named means and having a valving edge movable forwardly in the direction of said orifice for progressively decreasing the amount of port area effective for the flow of liquid into said chamber, said plunger having a transverse surface portion movable into contact with a. transverse surface portion of said rst named means for limiting the forward movement of said valving edge to a position more remote from said orifice than a port of said series. f

3. In a liquid atomizer, means forming a whirl chamber having an outlet orifice in an end wall thereof and a series of tangentially directed inlet ports for liquid distributed circumferentially and longitudinally throughout a circumferential band in an enclosing cylindrical wall, means for varying the effective fiow area of said ports comprising a plunger sleeve telescoping exteriorly with said first named means and axially movable in oppojsite directions for progressively increasing and decreasing the amount of port area effective for the flow of liquid into said chamber, said sleeve having an inner circumferential recess cooperating with said first named means to form an annular space adjacent the entrances to said ports, said sleeve having means for admitting liquid to said annular space, said recess extending longitudinally of said sleeve a distance at least equal to the width of said band of ports, and means for moving said sleeve axially to and from a position wherein said recess entirely embraces all ports within said band.

4. In the mechanical atomization of liquid fuel for combustion purposes wherein the fuel is directed tangentially of a whirling zone under pressure and is discharged from said zone through an orifice to form a divergent spray of atomized fuel particles, the method of controlling the fiow of fuel to said zone and through said orifice, for rates of flow throughout a wide operating range, which comprises, regulating the rate of fuel flow into said zone for lower rates of iiow within said operating range by varying the pressure of the fuel while maintaining a predetermined minimum effective fuel flow area; and, for higher rates of fiow within said operating range, by regulating the area effective for fuel fiow into said zone simultaneously with variations in fuel pressure.

5. In a liquid atomizer arranged for wide range operation, means forming a, whirl chamber having an outlet orifice, means forming inlet ports circumferentially and longitudinally displaced for admitting liquid to said chamber under pressure, said ports beingdisplaced in one of said directions to an extent placing a group of ports in overlapping relation in said one direction and at least one other port spaced in its entirety in the same direction from all ports of said group to provide an intervening unported space, valving means movable in said one direction of displacement for varying the effective flow area of said ports, and stop means arranged interiorly of said atomizerl for positively limiting the movement of said valving means to a position within the limits of said unported space for maintaining the entire fiow area of at least said one other port continuously effective.

6. In a liquid fuel atomizer arranged for operation over a wide range of capacities, means forming a whirl chamber having an annular Wall and` an outlet orifice in alignment along a common `enlaces axis, means forming a plurality of inlet ports distributed about said chamber for admitting liquid to said chamber under pressure, said ports being longitudinally displaced to an extent providing an unported annular wall space separating at least one of said ports from all remaining ports of said plurality, and valving means arranged for and substantially limited to rectilinear sliding movement relative to said annular wall for varying the effective flow area of said ports, said means forming said whirl chamber and said valving means having transversely arranged portions adapted to be brought into contact for preventing port-area reducing movement of said valving means beyond the limits of said unported space, thereby establishing a predetermined minimum capacity effective ow area of constant value through at least one of said ports and confining the variation in eifective flow area for higher capacities to said remaining ports.

7. In a liquid fuel atomizer arranged for operation over a wide range of capacities, means forming a whirl chamber having a cylindrical enclosing wall and having an outlet orifice in an end wall thereof in alignment with the central axis of said chamber, means forming a series of inlet ports distributed longitudinally of said enclosing wall and opening therethrough substantially tangentially into said chamber, said series of ports including a port section comprising at least one port of circular cross section throughout longitudinally displaced in its entirety from a port section comprising the remaining ports of said series to provide an intervening unported annular space between said port sections,v said cylindrical wall terminating in anannular surface arranged transversely of said axis at the end opposite said orifice, means for varying the total effective ilow area of said ports comprising a plunger telescoping with'said enclosing wall and having a valving edge movable forwardly in the direction of said orifice for progressively decreasing the amount of port area effective for the iiow of liquid fuel into said chamber, and means comprising a shouldered portion of said plunger adapted to engage said annular end surface for preventing forward movement of said valving edge beyond the limits of said unported annular space.

8. In a liquid atomizer, means forming a whirl chamber having an outlet orifice in an end wall thereof and a series of tangentially directed inlet ports for liquid distributed longitudinally thereof in an enclosing cylindrical wall, means for varying the effective ow area of said ports comprising a plunger telescoping with said first.

named means and having a valving edge movable forwardly in the direction of said orifice for progressively decreasing the amount of port area effective for the iiow of liquid into said chamber, means for moving said plunger including a movable spindle having an axially adjustable connection therewith, and means limiting the forward movement of said valving edge to a position more remote from said orifice than a port of said series.

9. In a liquid atomizer, means forming a whirl chamber having an outlet orifice, means forming a succession of inlet ports for admitting liquid to said chamber at varying pressures, means for progressively increasing the eifective flow 'area of said succession of ports from a predetermined minimum to an available maximum simultaneously with increases in pressures and solely in response to pressures above a predetermined pressure, said means including a valving member movable across said ports, said valving member l2 and said first named means having transversely arrangedv portions adapted for mutual v'contact' to establish said minimum4 effective "flow farea, means for holding said transversely arranged portions in contact at pressures below said predetermined pressure, and adjustable means for rendering said contact lholding means operable with respect to dierent predetermined pressure f:

values.

10. In a liquid fuel burner, a hollow body` member having a tubular extension, means forming a whirl chamber having an outlet oriicev removably assembled within the free end of said extension, said means providing a series of longitudinally distributed inlet ports for admitting fuel to said chamber, means for supplying fuel at varying pressures to said Ibody and through said tubular extension to said ports, a valve member longitudinally movable across ports of said series for increasing and decreasing the effective flow area of lsaid ports, means for moving said valve membercomprising a spindle connected thereto and extending longitudinally of said' tubular extension from within said body member, means for actuating said spindle comprising an element responsive to variations in fuel pressure within said body, said whir1 chamber having a surface forming a stop for positively limiting the port area reducing movement of said valve member to' a position of predetermined minimum effective port area, means arranged to exert a loading pressure on said spindle opposing the port area increasing movement of said spindle and thereby of said connected valving member, and means associated with said body member for supporting an end portion of said spindle and for adjusting the loading pressure of said last named means.

11. In a liquid fuel burner having a valv member movable longitudinally of a series of whirl v chamber ports for rendering varying amounts of port area effective for the flow of fuel into said chamber, a hollow body"member adapted to receive fuel Aat varying pressures and having a tubular extension -for conductingsaid fuel to said ports, a spindle for moving-'said valve member extending from withinsaidlbody member longitudinally of said tubular'extension, means for actuating said spindle comprising an element responsive to variations of fuel pressure within said body member, a spring arranged to exert a loading pressure opposing movement :of said spindle resulting from exposure of said element to increasing fuel pressures, a housing connected to said body member for supporting an end portion of said spindle having means for adjusting said springy loading pressure, anda removable enclosing cover for said housing, said housing having an opening therein rendering the movement of said spindle and spring visible upon removal of said cover.

12. In a liquid fuel atomizer arranged for wide range operation, means forming a whirl chamber having an annular wall and an outlet orifice in alignment along a common axis, means forming a plurality of longitudinally displaced inlet ports in said wall for admitting fuel to said chamber Aunder pressure, said ports being longitudinally displaced to an extent providing an unported annular wall space separating at leastone of said ports from all remaining ports of said plurality, longitudinally movable valving means for varying the effective flow area-of said ports, and stop means for positively limiting port area reducing movement of said valving means t0 a position within the limits of said unported Number space. 1,051,908 JAMES FLETCHER. 1,076,708 1,180,907 REFERENCES CITED 5 Re. 20,027 The following references are of record in the file of this patent. 2,349,221 UNITED STATES PATENTS 2,345,402 Number Name Date 10 1,452,264 Binks Apr. 17, 1923 1,904,509 Morse Apr. 1a, 1933 Number 2,223,055 Bergey Nov. 26, 1940 636.590 '159,320 Schutte May 10, 1904 415,274 1,969,954 Taylor Aug. 14, 1934 15 35,375 1,996,159 Kittredge Apr. 2, 1935 300.253

1,102,352 Peabody July 7, 1914 Name Date Normand Feb. 4, 1913 Schorr Oct. 28, 1913 Coen Apr. 25, 1916 Wettstein June 30, 1936 Schneider Mar. 14, 1933 Thomas Aug. 20, 1929 G01-rie May 16, 1944 Lubbock Mar. 28, 1944 FOREIGN PATENTS Country Date French 1928 British Aug, 23, 1934 Norwegian July 24, 1922 Italian Sept. 3, 1932

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