US2645527A - Nozzle construction for atomizing a liquid material by an atomizing gas - Google Patents

Description

July 14, 1953 Filed 001;. 17, 1950 C. C. WALTE NOZZLE CONSTRUCTION FOR ATOMIZING A LIQUID MATERIAL BY AN ATOMIZING GAS 2 Sheets-Sheet l INVENTOR ATTORNEY y 4, 1953 c. c. w AAAA RS 2,645,527

NOZZL STRUCTION FOR ATOMIZING A LIQUID \g IIII NTOR 4 45 lagnre 6 Zia/Zens ATTORNEY Patented July 14, 1953 NOZZLE CONSTRUCTION FOR ATOMIZING A LIQUID MATERIAL BY AN ATOMIZING GAS Clarence C. Walters, Willoughby, Ohio, assignor, by mesne assignments, to Crowley-Republic Steel Corporation, Cleveland, Ohio, a corporation of Ohio Application October 17, 1950, Serial No. 190,520

6 Claims.

This invention relates to a nozzle construction for atomizing a liquid material by an atomizing gas. More particularly, the invention relates to a nozzle construction of a type by which a liquid material, and particularly a material such as a molten material at some relatively high temperature and which material is chemically reactive, may be dispersed in a finely divided condition by being atomized by a gaseous fluid, which is supplied from the nozzle and which in a preferred form is not chemically reactive with the liquid material, so that the atomizing gas serves solely as such and does not react chemically with the liquid.

One particular use of a nozzle construction according to the present invention is disclosed and generally claimed in the copending applica tion of Darner and Walters, Serial Number 188,128, filed October 3, 1950. In that application a process and apparatus is disclosed and claimed for atomizing molten ferrous chloride by the use of a neutral atomizing gas such as nitrogen, the nozzle construction of the present invention being shown in substantial details in the drawings of that application, but not claimed in detail therein, and being claimed in the present application, which is independent of the particular process of the copending application aforesaid.

Other possible uses of the nozzle construction of the present application are, for example, for use as a part of a mechanism by which any molten material, whether a salt or other compound or a molten metal or other molten material, may be reduced to fine particles. For example, the device may be used in the process of oxidizing molten lead to form lead oxide. Another use of the device of the present application is in fuel injection nozzles for air-craft engines; for example, jet type aircraft engines, wherein it is desired to inject the fuel into a combustion chamber in a finely divided condition.

In the development of a process for reducing molten ferrous chloride in a liquid state to elemental iron by reacting this material with gaseous hydrogen, substantial difficulties were met, in that the nozzle, through which the molten ferrous chloride was sprayed in a finely divided condition into a reaction chamber, quickly became clogged. One possibility, thought might be the cause of this clogging, was the too rapid reaction between the ferrous chloride and the reducing hydrogen, causing the deposition of metallic iron on and around the which was difficulty was thought not to be the one which gave the most trouble. The trouble apparently was due to the fact that the molten ferrous chloride used contained very small amounts of metal-- 110 compounds, some of which were soluble and some insoluble in the molten ferrous chloride, one of such compounds being iron oxide (F6203).

All known makes of atomizing nozzles of the ten ferrous chloride, quickly blocked up in the atomizing gas opening. In tests conducted on a pilot plant scale, it was found that previously accepted principles of design of the annulus shape at thenozzle were inapplicable for the present purpose as the shapes tried appeared to cause a slight reversal of flow at the tip of the liquid jet, and consequential vibrational period at the tip of the nozzle, causing evaporation of the solution (ferrous chloride plus soluble metallic compounds), thereby concentrating it and allowing these metallic compounds to be precipitated or otherwise deposited from the solution on the nizzle tip. This condition continued until the gas opening was completely blocked.

In the case of the insoluble particles, these would undoubtedly cling to the particles deposited by the evaporation phenomenon. In the tests conducted, this occurred on the outside surface of the liquid jet and extended back approximately se inch from the extreme end and outward to the inside diameter of the annular gas passage causing complete blocking. After a con-' siderable number of trials, both of different shape and type nozzles and different materials from which the nozzle constructions'could be formed, the present invention was evolved. This invention resulted in a satisfactory nozzle for this particular purpose, which would not clog in a similar test extending over a reasonable time period.

The nozzle construction of the present invention may be summarized as one in which there is provided a central nozzle member having a central passage extending therethrough for the liquid material, combined with an outer nozzle member which cooperates with the central nozzle member to form an annular passage therebetween for the atomizing gas. Means are provided for suitably holding the nozzle members in a concentric arrangement. In this construction, the central passage of the central nozzle member has a circular cross section at the tip, which is concentric with the central axis of symmetry of the two nozzle members named. The tip portion nozzle tip. However, after some research, this 1 of the central nozzle member is further formed nozzle and which may, for example, be a molten material, such as molten ferrous chloride, may be supplied through the pipe II from any suitable supply source (not shown). At one side of the pipe II there is arranged a pipe l3, also suitably secured to the member in as by welding or otherwise and having its opening in alignment with a through passage which is open to the coupling surface l2 as shown at [4. The pipe 13 leads from a source of supply (not shown) of an atomizing gaseous fluid, so that the parts numbered ID, i l and I 3 may be collectively considered as supply means for a liquid (fluid) and for a gaseous fluid to be used for atomizing this liquid.

Carried by the member ID is a nozzle construction generally indicated at I5 including a support member l6 having a coupling surface ill at its upper end and having an outwardly extending flange [8 formed thereon for engagement in a suitably shaped recess in a clamp member I9. Suitable means, such as a plurality of nuts and bolts 20, may be used to clamp the member l9 and hence the nozzle construction !5 to the member [0.

Disposed between the coupling surfaces [2 and ii are a pair of endless gasket elements 2i and 22. These gasket elements are preferably in the form of substantially annular wires of a desired relatively soft metallic material and are preferably arranged concentrically with one another and also concentrically with the pipe H. The annular space formed between these gasket elements is in sole communication with the pipe 53. Thus, the gasket elements serve, in conjunction with the coupling surfaces 22 and H, to confine and maintain separate the liquid from the pipe l l and the gaseous fluid supplied through the pipe l3. While the composition of these gasket elements is not particularly critical, it should be of some material chemically neutral in respect to the liquid and the gaseous fluid supplied through the pipes II and [3 respectively, and also of some material having a melting point higher than any temperature to which the device may reasonably be subjected in its normal or intended use. In practice, the nuts and bolts 20 are tightened until the gasket elements 2! and 22 are sufficiently flattened to form,

effective barriers for the purpose indicated.

Extending axially through the support member l5 of the nozzle is a liquid passage 23. This passage is shown formed of two diameters meeting at a shoulder 24, which serves to support a relatively heavy perforate support such as a screen 25. Resting upon the screen 25 is a cupshaped screen or a filter member 26, having its upper, open end loosely received within the bore of a tapered hollow plug 21 which is seated in the upper end of the passage 23, as shown. The elements 25, 26 and 27 may be removed for cleaning or replacement, as may be necessary. Other equivalent filtering arrangements may be used if desired. In some instances, also these elements may be wholly eliminated as they serve the sole purpose of filtering the liquid supplied to and through the nozzle.

Located in and by the nozzle member [8 is a central nozzle member 28, provision being made for this member being assembled and disassembled and for accurately centering this member or replacements thereof. For this purpose, the members l6 and 28 are formed with mating conical surfaces concentric with the axis of symmetry of these members and engaging one another over a substantial area of these surfaces as indicated at 29. Like the member [6, the central nozzle member 28 has an axial through passage generally indicated at 30, having at its lower or outer end a cylindrical passage portion 3| concentric with the center axis of symmetry, which is indicated in several of the figures as a broken line c--c.

Arranged to be secured to the central nozzle member 28 is an outer nozzle member 32, which has its lower or outer end (as seen in Figs. 1 and 3) spaced from the outer end or the tip portion of the nozzle member 28 to provide an annular passage for the atomizing gas supplied through the nozzle construction. In order that this passage be uniform about the central axis of symmetry of the nozzle as a whole, means are provided for centering and positioning these nozzle members 28 and 32, with respect to each other. As shown, the central nozzle member 28 is provided with an outwardly extending flange 33, which is arranged to be engaged by a portion of a flange 34 formed on the outer nozzle member 32. While the engagement between the contacting portions of these flanges 33 and 34 can be over a substantial surface area of both as by forming both with mating conical surfaces, and while it is also contemplated as a possible alternative that these contacting surfaces of the flanges 33 and 34 might both be spherical, there is shown in the accompanying drawings a preferred form of these engaging surfaces in which the flange 33 is provided with a concave conical surface, which is engaged by a convex spherical surface formed on the flange 34. Thus, the two surfaces will engage one another around a circular line, which is at all points tangent to the spherical surface of the flange 34 as seen, for example, in longitudinal central section as illustrated in Figs. 1 and 3. This circular line of engagement at the point of tangency of the conical surface and the spherical surface is concentric with the central axis of symmetry 0-0 of the entire nozzle construction.

Means are provided for holding the nozzle members 32, 28 and I6 together in their normal assembled relationship as shown in the drawings. For this purpose, the outer nozzle member 32 is provided on the underside of the flange 34 with a downwardly directed annular shoulder 35. This shoulder is engaged by an inwardly directed portion of a nut member 35 which may be threaded onto a depending portion of the supporting member 18- as shown in Fig. 1. To facilitate the assembly and disassembly of the parts, the nut member 36 may be formed externally in a hexagonal or some other shape, so that it may be engaged by a suitable tool for tightening the nut onto the nozzle member I6. 7

For the distributing of the atomizing gas substantially uniformly about the central axis of symmetry of the nozzle, in order to secure a desired type of atomizing action, a number of Dassage means and a plenum chamber are provided. As shown, the annular space between the gasket elements 2! and 22 lies directly above an annular groove 3'! formed in the plane coupling surface ll. The lower end of this groove 31 communicates through a plurality of inclined bores 38, each having large and then small diameter portions, with the engaging conical surfaces 29 of the members [6 and 28. In the present instance, there are four such bores 38, although some other number, greater or less than four, could be provided. The bores 38 are preferably equiangularly disposed about the central axis of symmetry of the nozzle. At their lower ends the bores 38 communicate with an annular groove 39 extend-. ing inwardly from the outer conical surface of the member 28, so that gas may be redistributed around the annular groove 39 and so that the uniform supply of the gaseous fluid through the nozzle does not depend upon any particular registration of bores in the nozzle members I 6 and 28 respectively. Located in the nozzle member 28 and extending therethrough parallel with and in substantially equiangular spaced relationship about the central axis of symmetry are a plurality of bores -16 communicating at their upper ends with the annular groove 39 and at their lower ends with the underside of the flange 33 above the plenum chamber which is defined by this fiangaby an extended central portion 41 of the central nozzle member 28 and by the inside of a cup-shaped or hollowed out part of the outer nozzle member 32. This plenum chamber is indicated at 2. Gaseous fluid supplied to the plenum chamber through the bores 40, which are preferably of a number greater than the number of bores 38, there being eight such bores 48 in the form shown, will be substantially uniformly distributed around the plenum chamber, so that as this gaseous fluid issues from the plenum chamber, it will be uniformly supplied as an annular curtain or stream of gas.

The present invention is particularly concerned with the shape, arrangement, and relative dimensions of the annular passage from the plenum chamber 22 to the outside or nozzle tip through which the atomizing gaseous fluid flows in the direction of the central stream of liquid to be atomized. It has been found that various features of these arrangements are quite critical and the severalarrangements, considered as a whole, must necessarily be substantially as herein taught in order that the liquid be atomized efiiciently, and in order that solid material not build up at the nozzle tip, which will cause the plugging of the nozzle. However, whatever be the case, the following details as to the nozzle tip and the arrangements and relationships of the parts thereof have been found to be essential.

The central nozzle member 28 has, as stated, an extension 4| which tapers as shown at 43 to a smaller outside diameter and which forms a taperingportionof the annular plenum chamber 42. This feature per se is not one of the essential relationships of this invention, but is described in order that the description be complete. The end portion of the central nozzle member 28 below the tapered portion 43 is formed with an outwardly enlarged portion generally indicated at M. This portion cooperates with the outer end portion 45 of the outer. nozzle member 32 to define the end portion of the annular passage 46. This end portion of the annular passage 46 is defined as seen in Fig. 3 by substantially parallel, conical surfaces 47 of the enlarged portions 44 and 48 of the portion 45 at the outer end of the outer nozzle member 32. In other alternative forms of the invention the surfaces defining the annular passage may not be solely parallel or conical, or, as to each such surface, a part of a single cone. The requirements for equivalency in order that the desired results in accordance with this invention be attained, will be specifically set out hereinafter. The conical surface 47, Fig. 3, meets the cylindrical portion 3! of the central bore at a relative .sharp edge 49, which is, in fact, a circular-line concentric with the center axis of symmetry cc of the nozzle. In general, it is 3 V believed to be substantially essential that the outer surface of the enlarged portion 44 be a surface of revolution, although within this requirement, it may be varied as hereinafter noted; and that it meets the surface defining the outer end of the liquid passage 3| in a relatively sharp circular edge, concentric with the center axis cc. Thus, the liquid passage, at its outer end, must have a circular cross section concentric with the axis cc, although the shape and disposition of other portions of the liquid passage are not critical.

If the nozzle members be viewed in a central longitudinal plane containing the central axis cc, for example as in the section shown in Figs. 1 and 3, there may be drawn an inclined line 50, which is parallel with the surfaces 41 and 48 of Fig. 3. and midway therebetween. This inclined line 5E3, if extended to intersect the central axis of symmetry as shown in Fig. 3 forms an angle a therewith as shown. This angle has been found to be quite critical to the successful operatio of the nozzle. This angle should be between about 35 and about 60. Further, in considering this angle, it has been found that as the angle is increased, toward the upper limit as stated, the degree of atomization of the liquid particles increases. On the other hand, as the angle a is increased, the amount of pressure required to force the liquid through the nozzle also increases, prob-ably due to some back pressure effect of the atomizing gas. Angles of a less than about 35 will not result in a desired atomization, while angles of a greater than about 60 result in such a high back pressure effective on the liquid flow through the nozzle as to defeat normally desired operations.

It has also been found that the character, shape and uniformity of the intermediate portion of the nozzle construction connecting the portion of the annular passage 45 formed by the parallel conical walls ll and 48 with the plenum chamber 42 is somewhat critical. For example, when viewed in such a plane or section, as shown in Fig. 3, the configuration of the two sides of this intermediate portion must be symmetrical on both sides of the inclined line 50. In fact it is a requirement for all embodiments of the invention that the shape of the surfaces defining the sides of the annular passage 46 shall be symmetrical with respect to the inclined line 511. As shown, in Fig. 3, the shape of these intermediate portions in each case is in effect toroidal and the radii of the toroids indicated at 'r and 1" should be equal. In any event, these curves, shown as circular in Fig. 3, are preferably smooth curves and are, of course, symmetrical on both sides of the inclined line 50.

If the inclined line 50 were rotated about the central axis cc of the nozzle, a conical surface would be generated, which for the purposes of the present application may be referred to as a reference surface. The outer end of the annular passage 46 terminates in a conical surface, concentric with the axis cc, inverted with respect to the conical reference surface aforesaid, and perpendicular to this reference surface at all points on the line of intersection thereof. This last named conical surface will contain the circular edge 49. I

In Fig. 4 is shown a modified form of the invention in which the modification is directed to the passage portion between that portion of the annular passage 46 defined by parallel conical surfaces 41 and 48 as in Fig. 3, on the one hand,

and the plenum chamber 42, on theother. As shown in Fig. 4, this intermediate portion. is

defined by sloping walls, which in effect are coniing between the parallel conical surfaces 4? and 48 on the one hand, and the side wall portions of the plenum chamber 42, on the other. These sharp shoulders again are symmetrical about the inclined line 50 and in this instance are formed as parts of a common conical surface concentric with the axis of symmetry -0 of the nozzle as a whole.

Fig. 6 shows a further modification in which the parallel sided portion ofthe annular passage is quite short, being defined by short conical surfaces 55 and 56, corresponding respectively to the longer surfaces 41 and 48 of the forms described above. The major part of the annular passage, in this form of the invention, is defined by relatively long conical surfaces and 58 connecting the surfaces 55 and 56 respectively with the inside of the plenum chamber.

Any other shapes for the walls of the annular passage within the principles herein set forth may be employed with desirable results. In this connection it is noted that the minimum width of the annular passage should be at the outlet end thereof and that at portions of this annular passage progressively inwardly from the outlet end, the width dimension may be constant or increase, but never decrease.

Another relationship which has been found to be somewhat critical in respect to the nozzle of the present invention, is the width or the minimum distance 17 across the annular passage between the conical surfaces 4! and 48, in a direction perpendicular to these surfaces and to the inclined line 50. I

In all forms of the invention this width or minimum distance across the annular passage is the width at the outlet of the passage measured in the plane of Figs. 3 to 7 inclusive and in a direction perpendicular to the inclined line 50. In the forms of Figs. 3 to 5 inclusive, this width remains constant for a substantial distance along the annular passage 46 as the surfaces 4? and 48 are parallel. This width is indicated in all forms of the invention as the dimension 1). The essential relationship in accordance with the present invention is that the dimension 27 should be at least as great as a dimension a, which may be defined as the length of the parallel sided portion of the annular passage 46 having a minimum width and measured parallel to the inclined line 50 from the outer end of the passage 46. The manner in which the dimensions a and b are measured is illustrated in Figs. 3 to 6 inclusive of the drawings.

It has been found that the dimension b should be at least as great as the dimension (1. Preferably also, the dimension (1 should be kept to a minimum consistent with adequate strength in the parts. In any event, while the dimension a may be as great as b, it should not exceed 12.

As an example of a nozzle constructed in accordance with the present invention, a nozzle was made substantially as shown in Figs. 1 to 3, using commercially pure nickel as the material of construction. This nozzle was used in the process of the copending application, Ser. No. 188,128, above referred to, for the supplying of liquid ferrous chloride at the rate of about 1 pounds per minute, the liquid being at a temperature of about 1600 F. Nitrogen was used as the atomizing gas and was supplied at the rate of about 2 cubic feet per minute (measured at 70 F. and 8 p. s. i. back pressure); The nitrogen was heated, however, at the nozzle to a temperature of about 1600 F. and at a pressure of about 8 pounds per square inch. The nozzle so used had a central orifice portion 3i for liquid cylindrical in form and .0625" in diameter. The dimensions a. and b defined as set forth above, were each 0.40". The angle a. of this nozzle was 45, which is the preferred, specific value of this angle. The nozzle operated successfully over a substantial period of time, both from the point of view of n0n-c1og ging and from the point of view of atomization. The drawingsFigs. 1, 2 and 3are substantially scale drawings of this nozzle, the essential dimensions of which have been given.

While there has been shown and described herein a preferred construction of a nozzle and some of the means appertinent thereto, and while certain modifications have been particularly described or suggested, other changes may be made as will suggest themselves as equivalents to those skilled in the art from the foregoing description. I do not wish to be limited, therefore, ex cept by the scope of the appended claims, which are to be construed validly as broadly as the state of the prior art permits.

What is claimed is:

1. A nozzle construction for atomizing a liquid material by an atomizing gas, comprising a central nozzle member having a passage extending therethrough for said liquid material, an outer nozzle member cooperating with said central nozzle member to form an annular passage therebetween for said atomizing gas, means for holding said nozzle members together in a concentric arrangement, said nozzle members having their portions defining the end portion of the first named passage for liquid material and said annular passage formed of surfaces of revolution concentric with a central axis, said first named passage having a circular cross section at the tip of said central nozzle member concentric with said central axis, said tip being formed with an end portion defining the inside of said annular passage, said annular passage having an outer end portion which is formed by cooperating, substantially conical parallel surfaces of said end portion of said central nozzle member and of an end portion of said outer nozzle member, said nozzle members when viewed in central longitudinal section in a plane containing said central axis being formed with their portions defining said annular passage symmetrical about a line in said plane inclined in respect to said central axis, said inclined line if rotated around said central axis defining a conical reference surface, the outer end portion of said annular passage terminating in a conical surface inverted in respect to said conical reference surface and perpendicular thereto at all points on the line of intersection thereof, said inclined line forming with said central axis an angle of about 35 to about 60, an annular plenum chamber for the atomizing gas formed between said central nozzle member and said outer nozzle member and communicating With said annular passage, and said annular passage having its minimum width measured between the parallel sides of said annular passage at its outer end, which width is measured in a direction perpendicular to said inclined line, said minimum width being at least as great as the dimension, measured parallel to said inclined line and from said outer end of said passage of the parallel sided portion thereof.

2. A nozzle construction according to claim 1, where said angle between said inclined line and the central axis is about 45.

3. A nozzle construction in accordance with claim 1, wherein said annular passage is formed by surfaces; each of which when viewed in longitudinal axial section includes a smoothly curved surface in the portion of said annular passage nearest to said plenum chamber.

4. A'nozzle construction in accordance with claim 1, wherein the portion of said annular passage connecting said plenum chamber with the end portion of said annular passage is defined by toroidal surfaces.

" 5. A nozzle construction in accordance with claim 1, wherein the end portion of said annular passage is defined by parallel conical surfaces, and wherein the portion of said annular passage connecting said plenum chamber with said end portion of said annular passage is formed by surfaces, each of which is a conical surface extending from one of said parallel surfaces to a surface defining said plenum chamber, so that this connecting portion of said annular passage diverges from the width of the parallel sided portion of said annular passage to the width of said plenum chamber.

6. A nozzle construction in accordance with claim 1, wherein said annular passage is defined by substantially parallel conical surfaces and is connected to said plenum chamber by sharp shoulders which are formed by said parallel conical surfaces and by parts of a common conical surface perpendicular to said parallel conical surfaces.

CLARENCE c. WALTERS.

References Cited in the file ofthis patent UNITED STATES PATENTS Number Name Date 1,930,373 Steubenrach Oct. 10, 1933 2,102,382 Roselund Dec. 14, 1937 2,125,764 Benoit Aug. 2, 1938 2,136,668 Binder Nov. 15, 1938 2,207,765 Stevens July 16, 1940 2,236,551 Striegel Apr. 1, 1941 2,434,911 Denyssen June 27, 1947 FOREIGN PATENTS Number Country Date 263,558 Switzerland Dec. 1, 1949

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