US2950062A - Screen framing structures for fluid mixing devices - Google Patents

Description

PRIOR ART 8 1960 E. P. AGHNIIDES I 2,950,062

SCREEN FRAMING STRUCTURES FOR FLUID MIXING DEVICES Filed Aug. 2, 1956 FIG. I.

Fluid Under Pressure K22 20' l l 22 Q A I II FA A IL A A A A A 4E FIG. 2 A T INVENTOR ELIE P. AGHNIDES ATTORNEYS SCREEN FRAMING STRUCTURES FOR FLUID MIXING DEVICES Elie P. Aghnides, 46 W. 54th St., New York 19, N.Y. Filed Aug. 2, 1956, Ser. No. 601,710

Claims. (Cl. 239-431) The present invention relates to improvements in fluid mixing devices, particularly of the type described in my prior U.S. Patents No. 2,210,846, granted August 6, 1940, entitled Fluid Mixing Device and No. 2,316,832, granted April 20, 1943, also entitled Fluid Mixing Device. Such devices may be employed, for instance, in aerating water and they ordinarily comprise a casing having therein an upstream diaphragm and one or more downstream screens so proportioned and arranged with respect to each other that a whitish, bubble-laden coherent jet of water emanates from the casing. Such fluid mixing devices or aerators also include air inlets in the aforementioned casing either in the side wall thereof or adjacent the discharge end thereof, and these air inlets communicate with a mixing chamber located between the aforementioned upstream diaphragm and downstream screen or screens.

In providing for the aforementioned screen or screens adjacent the downstream end of the fluid mixing device, the said screen or screens are ordinarily placed in frame structures to provide support for the screens within the casing; to prevent bits of screen material from becoming separated from the remainder of the screen and being discharged with the aerated fluid; and to provide, in many cases, spacing between plural screens. The particular types of framing structures employed heretofore have been subject to a number of disadvantages. In particular, they appreciably reduce the effective screen area whereby the mixing, of air and water for instance, is not as eflicient as might otherwise be the case. In addition, the frames suggested heretofore have not provided for appreciable spacing between plural screens unless the frame material itself is relatively thick; and such thick framing structures have in turn served to further reduce the effective screen area.

The present invention serves to obviate the foregoing difliculties through the provision of improved framing structures for the aforementioned downstream screens whereby the said framing structures act to retain the screens without appreciably reducing the effective crosssectional area of the mixing screen or screens themselves, and further provide desired spacing between plural superposed screens when such a plurality of screens are employed in the fluid mixing device or aerator.

It is accordingly an object of the present invention to provide improved framing structures for mixing screens in fluid mixing devices.

A further object of the present invention resides in the provision of improved fluid mixing devices or aerators wherein the mixing chamber and/or the discharge end of the aerator may be larger for a given overall diameter of the body of the casing, and whereinfar more effective aeration of fluids can be effected than has been the case heretofore.

Another object of the present invention resides in the provision of improved framing structures for one or more mixing screens in a fluid mixing device; which framing structures minimize the effective mixing screen area lost due to the framing.

A still further object of the present invention resides in the provision of means which effect substantial spacatent 0 ice ing between superposed screens in a fluid mixing device and which provide this spacing in a more efficient manner than has been the case heretofore.

In providing for the foregoing objects and advantages, the present invention contemplates the provision of improved framing structures for the mixing screen or screens in a fluid mixing device, and these framing structures are disposed about the peripheral edge of the said screen or screens and include a framing portion which extends in a direction transverse to the plane of the screen or screens. The actual structures which provide the aforementioned advantages may comprise frames having an edge portion reversed upon itself with the screen structure being inserted between these reversed portions of the screen frame or adjacent one edge of such a reversed portion. In the alternative, the improved screen frames of the present invention may have a substantially L- shaped cross-section, and the screen material may be retained in place Within this L-shaped screen frame through provision of a retaining ring.

In the several embodiments of the present invention thus provided, each improved frame has an edge portion which is substantially L-shaped; and the screen material itself may be retained within this substantially L-shaped frame structure by various means which will be described. Due to the provision of the L-shaped configuration, however, the actual effective area of the mixing screen is increased substantially overthose suggested heretofore; and in addition, the portion of the 'L-shaped frame which extends transverse to the plane of the screen acts as a support for a further screen superposed thereon, whereby desired spacing between screens can be effected readily.

The foregoing objects, advantages, construction and operation of the improved framing structures comprising the present invention will become more readily apparent from the following description and accompanying drawings, in which:

Figure 1 is a partial cross-sectional view of a fluid mixing device or aerator constructed in accordance with the present invention and illustrating two possible improved screen frames in accordance with the present invention; and

Figures 2A through 2D illustrate and compare various improved framing structures constructed in accordance with the present invention.

This application is a copending application with analogous subject matter of my prior copending application Serial No. 560,299, filed January 20, 1956, and entitled, Fluid Mixing Devices.

Referring now to Figure 1, it will be seen that in accordance with the present invention, a fluid mixing device or aerator may comprise a casing 10 which includes means (not shown) for connecting the said casing at its upstream end to a source 11 of fluid under pressure. Disposed within the said casing 10 is a diaphragm 12, and one or more mixing screens designated as 13 and 14. Diaphragm 12 may take various configurations, and in accordance with the particular form illustrated in Figure l, the said diaphragm comprises a shallow inverted cup having a plurality of scallops or cut-outs 15 along the lower peripheral edge thereof, and having a plurality of orifices 16 in the upper surface thereof. As a result, fluid 11 passing in a downstream direction through the casing 10 is caused to be broken into a plurality of small jets .as the said fluid passes through orifices 16, and these jets are intermixed in the area downstream of diaphragm 12 with air passing via air inlets 17 in casing 10, and thence via scallops or cutout portions 15 into the mixing chamber downstream of the said diaphragm 12. This mixing of air and fluid is enhanced by the resistance aiforded by mixing screens 13 and 14; and the effective area of the said screens 13 and 14 relates directly to the amount of aeration or fluid mixture ultimately provided by the overall structure.

Before proceeding with a detailed discussion of theparticular screen structure shown in Figure 1,-attention is invited to Figure 2 Whichillustrates the framing structures utilized heretofore, as Well as certain improved framing structures in accordance with the present invention. Thus, referring to Figure 2A, it will be seen that mixing screens of the type utilized in the past have often taken the form of screens 20 and 21. It should be noted that screens 20 and 21 may be superposed one upon the other when it is desired to provide two mixing screens spaced from one another; and it will be understood by those skilled in the art that a single mixing screen, or if desired two (or more) superposed screens, can be employed in accordance with the several embodiments of the present invention. The screens 20 and 21 have, in the past, been framed by a framing structure disposed adjacent the periphery of the screen and having a subis about 18 mm., and this means that the effective crosssection of the screen area in screens 20 and 21 is reduced by over 25% due solely to the frame structures 22 and 23. It should further be 'noted that the screens 20 and 21 are spaced from one another by the frame structures 22 and 23; and this spacing depends directly upon the thickness of the frames 22 and 23. In order to have substantial spacing between screens 20 and 21, the thickness of the frames 22 and 23 must often be appreciable, and the thicker the frame the greater will be the width of the rim and the smaller will be the effective area of the resulting mixing screen. Moreover, the thick frame structures which have often been required, to provide the desired spacing between superposed screens, presents an appreciable manufacturing problem; and even when such thick frames are provided, the spacing between adjacent screens is still less than might be desired.

In order to obviate these disadvantages, various improved screen structures maybe' provided in accordance with the present invention. Referring to Figure 2B, it will be seen that, in accordance with one embodiment of the invention, a pair of mixing screens such as 24 and 25 may be retained in frames 26 and 27, which frames are constructed in accordance with one embodiment of the present invention. In particular, each of the frames 26 and 27 is reversed upon itself, for instance at 28 and 29, and the screens 24 and 25 may be retained within the frame by insertion of the edge portion of the screen, as at 30 and 31, between the outer surface of the frames 30 and 31 and the inner reversed portions 28 and 29 thereof. When this particular framing structure is employed, the actual material comprising the frame can be quite thin without detracting from the structural rigidity afforded by the overall structure; and the actual effective area of the screens 24 and 25 is increased to the diameter B. In

addition, it will be noted that due to the reversed configuration of the screen frame, the edge of the frame is upstanding in configuration and extends in a direction transverse to the plane of the screens 24 and 25 whereby a frame such as 26 can be supported upon a further frame such as 27, thereby to provide substantial spacing between the screens 24 and 25. Thus, the effective area of screens 24 and 25 is increased substantially over that of the screens 26 and 21; and in addition, the screens 24 and 25 are spaced a greater distance apart from one another than is the case with respect to the screens 29 and 21.

It will be appreciated that the upstanding portions of the frames 26 and 27 are illustrated in Figure 2B as disposed substantially at right angles to the plane of the screens 24 and 25; and such a substantially right angular configuration is in fact illustrated in the several other embodiments of the invention to be described. In practice, such a right angled configuration is not mandatory and the upstanding portion of the screen frame can extend *at any desired angle to the plane of the screen, whereby any desired spacing can be effected between the screens.

A further embodiment of the present invention is also illustrated in Figure 2C for the screen 32 and frame 33. Frame 33 again includes a portion34 reversed upon the remainder of the frame 33, whereby the edge of the frame has an upstanding configuration with respect to the plane of screen 32. However, in this particular embodiment of the invention, the screen 32, rather than being inserted between the outer edge of frame 33 and the reversed portion 34, is held in position below the lower edge 35 of the reversed portion 34by the clamping action of this reversed portion itself. Inasmuch as screen 32 is not inserted between portions 33 and 34, the effective diameter of screen 32 is increased still further with respect to the diameters of screens 20, 21, 24 and 25; and this further increased diameter is designated C in Figure 2C. Again, the frame structure 33 may be formed of relatively thin framing material and the frame structure employed provides an upstanding portion which can serve to space plural screens from one another and which at the same time does not detract from the effective screen area as much as has been the case heretofore. While a single screen 32 only has been illustrated, it will be appreciated that frames of the types designated 33 can be employed with plural screens superposed one upon the other. It will further be appreciated, as mentioned previously, that the upstanding portion of frame 33 may extend at any desired angle to the plane of screen 32.

Still another embodiment of an improved framing structure constructed in accordance with the present invention is illustrated in Figure 2D for screen 36 and frame 37. In this particular embodiment of the invention, which is analogous to the embodiment already described in reference to screen 32 and frame 33, the frame 37 has an edge configuration which is substantially L- shaped; and the screen 36 is retained in place Within the said L-shaped frame by a ring 38 inserted into the said frame. Screen 36 is accordingly held in place between the uppermost edge of the base of L-shaped frame 37 and the lower surface of clamping ring 38 in a manner analogous to the clamping elfectof edge 35 of frame 33 already discussed. The effective diameter of screen 36 is also designated C, and corresponds to the effective diameter of the screen 32, already discussed.

In each of the embodiments of the invention thus described in Figures 2B to 2D, the screen is positively retained in place by a framing structure which may be constructed of thinner material and which provides greater spacing between superposed screens and detracts less from the effective screen cross-sectional area than has been the case heretofore; and these substantial improvements are effected in each case by providing a framing structure which has an upstanding portion extending trans verse to the plane of the screen at any desired angle thereto. It will be appreciated of course that the several upstanding portions may actually extend in a downward direction with respect to the plane of the screens rather than in an upward direction, without departing from the principles of the present invention. Accordingly, it will be understood that the terms upper, lower, above, below, and analogous such terms employed in the specification and appended claims are relative terms only, and are meant to refer to the relative positions of the several elements comprising my invention rather than to the abstract positions of each element per se.

Returning now to Figure 1, it will be seen that screens 13 and 14, previously described, are retained in place by framing structures 40 and 41 constructed substantially in accordance with the preceding discussion. In particular, frame 40 is analogous to frames 26 and 27, and screen 13 is accordingly inserted between the reversed portion of the screen frame. Frame 41 is analogous to frame 33, already discussed, and the screen 14 is retained in place beneath the lowermost edge of the reversed portion of the said frame 41. In addition, the particular flames 40 and 41, illustrated in Figure 1, rather than terminating directly beneath the plane of the screens, as was the case in the several embodiments described in reference to Figure 2, include a skirt whereby the screens may be superposed in nested relation with one another. In particular, frame 40 includes a skirt 42 and frame 41 includes a skirt 43; and the skirt 42 may be inserted as illustrated into the upper edge of frame 41 whereby the screens are supported in superposed relation to one another and in nested relation to one another, as illustrated. In addition, casing may include an inwardly extending projection 44 or a plurality of such projections for supporting the lowermost frame, such as 41, adjacent its skirt, such as 43.

While I have thus described improved framing structures in accordance with the present invention, many variations will be suggested to those skilled in the art, and it must therefore be stressed that the foregoing description is meant to be illustrative only and should not be considered limitative of my invention. All such variations and modifications as are in accord with the principles described are meant to fall within the scope of the appended claims.

I claim to have invented:

1. A fluid mixing device comprising a casing having a first fluid inlet, a fluid outlet downstream of said first fluid inlet, and a second fluid inlet communicating with the interior of said casing between said first fluid inlet and said fluid outlet, fluid mixing means within said casing downstream of said first fluid inlet including at least one foraminous surface, and a frame surrounding said foraminous surface, said frame including a relatively narrow annular flange disposed below the periphery of said foraminous surface, said frame further including an upstanding retaining edge extending from said flange, in a direction substantially transverse to said foraminous surface, to a position substantially above said foraminous surface, said retaining edge comprising a pair of substantially coaxial cylindrical members of differing diameters, the outer one of said cylindrical members surrounding the said foraminous surface and the inner one of said cylindrical members including portions engaging said foraminous surface as well as said outer cylindrical member, the length of said retaining edge being substantially greater than the thickness of either said cylindrical member, and a further foraminous surface resting upon the uppermost extremity of said upstanding retaining edge whereby said further foraminous surface is spaced from said first mentioned foraminous surface by a distance substantially greater than the thickness of the material constituting said retaining edge.

2. A mixing structure for a fluid mixing device comprising a conduit, supporting means facing the interior of said conduit, a foraminous surface including a substantially planar portion extending across said conduit, a frame for said foraminous surface disposed adjacent the periphery of said surface, said frame including a relatively narrow annular lip extending in a plane substantially parallel to that of said foraminous surface planar portion, said annular lip being disposed below the peripheral edge of said foraminous surface for supporting said surface, said frame further including a first elongated member extending from said narrow annular lip in a direction transverse to said surface and to said annular lip, and a second elongated member comprising a. portion of said first member reversed upon itself and extending in a direction substantially parallel to said first member toward said annular lip and foraminous surface planar portion, the lengths of said first and second members being substantially greater than the thicknesses thereof, said frame resting on said supporting means within said conduit with said first and second elongated members extending substantially parallel to the interior walls of said conduit whereby said foraminous surface is disposed within said conduit in a direction substantially transverse to the internal walls thereof.

3. Mixing means for a fluid mixing device compris ing a conduit, said mixing means including a substantially fiat screen surface, a frame for supporting said screen surface within said conduit, said frame including a flat ring disposed adjacent the periphery of one side of said screen surface, and an upstanding edge, integral with said flat ring, and extending in a direction transverse to the screen surface to a position appreciably above the other side of said screen surface, the length of said upstanding edge being substantially greater than the thickness thereof whereby said ring and upstanding edge cooperate with one another to provide a frame having a substantially L-shaped edge, and a substantially cylindrical member disposed within said upstanding edge above said other side of said screen surface, said cylindrical member hav ing a thickness less than its length and including portions engaging both said upstanding edge and said screen surface thereby to retain said screen surface in position adjacent the junction of said flat ring and said upstanding edge.

4. The combination of claim 3 wherein said cylindrical member comprises an integral portion of said upstanding edge reversed upon itself and extending in a direction substantially parallel to said upstanding edge from the uppermost extremity of said upstanding edge to said screen surface. 7

5. Mixing means for an aerator comprising a casing having support means, said mixing means including a foraminous surface, a substantially L-shaped frame surrounding said surface, said L-shaped frame having a relatively short base lying below the periphery of said foraminous surface and a relatively long outwardly positioned upstanding edge extending from said short base to a position substantially above said foraminous surface, a portion of said outwardly positioned upstanding edge being reversed upon itself to define an inwardly positioned upstanding edge connected to said outwardly positioned edge and extending in a direction substantially parallel to said outwardly positioned edge toward said foraminous surface, the height of said upstanding edges being greater than the thickness thereof, said frame resting on said support means on the interior of said casing, and a further foraminous surface supported within said casing adjacent the reversal portion of said interconnected upstanding edges.

References Cited in the file of this patent UNITED STATES PATENTS 948,421 Hax 2. Feb. 8, 1910 968,983 Riedy Aug. 30, 1910 1,087,708 Bendix Feb. 17, 1914 1,617,504 Shinn Feb. 15, 1927 2,174,577 Friedman Oct. 3, 1939 2,210,846 Aghnides Aug. 6, 1940 2,241,229 Williams May 6, 1941 2,334,802 Zuckermann Nov. 23, 1943 2,541,854 Bachli et al Feb. 13, 1951 2,585,729 Berman Feb. 12, 1952 2,633,343 Aghnides Mar. 31, 1953 2,643,104 Holden June 23, 1953 2,717,772 Palivos Sept. 13, 1955 2,747,930 Hyde May 29, 1956

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