Automatically adjustable fluid distributor

Abstract: A fluid distribution apparatus comprises first and second structures 60,72 having first and second spaced surfaces 66,82, respectively. A rotatable member 84 located between first and second spaced surfaces, the rotatable member and the first and second spaced surfaces defining a dual nozzle including a first annular nozzle outlet defined between the rotatable member 84 and the first spaced surface 66 and a second annular nozzle outlet defined between the rotatable member 84 and surface 72. A central opening 92 is defined through the rotatable member, for conducting fluid to one of said first and second annular nozzle outlets. Vanes 96,98 cause rotation of the rotatable member 84 as fluid flows out of the dual nozzle.

Description: The present invention relates generally to apparatus for distributing water and other fluids, and more particularly, but not by way of limitation, to a water distributor for use in a cooling tower. Typical prior art cooling towers utilise a network of overhead sprinklers, similar to a building fire sprinkler system, the network developing a plurality of overlapping circular spray patterns, distributing water over the upper surface of a layer of fill material, through which the water flows downward as air is drawn upward through or across the fill material, and thus heat is transferred from the water to the air. It is important to obtain as uniform a water distribution as possible, so that the water will uniformly flow through the fill material across the entire cross-sectional area of the tower. If the water distribution is not uniform, channels will develop which are substantially void of water and thus provide a low pressure air path, thus greatly reducing the efficiency of the heat exchange operation. Furthermore, the only way these sprinklers can be adjusted is by replacement of the sprinkler orifices with different size orifices. These orifices are conventionally relatively small and are prone to clogging by debris and corrosive build-up which is a natural result of handling the rather dirty water typically encountered in industrial cooling situations. As the sprinklers clog, further irregularities are created in the water distribution pattern thus further decreasing the efficiency of the cooling tower. A fluid distribution device in accordance with the precharacterising portion of claim 1 is disclosed in US-A-3 189 283. This is particularly intended for distributing sewage over a filter bed and is to be self-cleaning and is arranged to have a floating deflector plate, which can rotate gradually, on the open end of a fluid supply pipe. The deflector plate has a central aperture so that when the apparatus is placed close under a ceiling two sprays are produced, one from the underside of the deflector plate and one via the aperture and deflected off the ceiling. According to the present invention, there is provided a fluid distribution apparatus comprising first and second structures having first and second spaced surfaces, respectively; a rotatable member located between said first and second spaced surfaces, the rotatable member and the first and second spaced surfaces defining a dual nozzle including a first annular nozzle outlet defined between the rotatable member and the first spaced surface and a second annular nozzle outlet defined between the rotatable member and the second spaced surface; a central opening defined through said rotatable member, for conducting fluid to one of said first and second annular nozzle outlets; and means for rotating said rotatable member as fluid flows out of the dual nozzle, characterised in that said second structure is mounted on a support connected to said first structure, said support extending through said central opening, so that an annular flow passage is defined between said central opening and said support, to permit lateral mobility of said rotatable member. By the lateral mobility the rotatable member will "float" on a water bearing defined by the two outward flowing annular streams thus establishing said streams. In order that the present invention may more readily be understood, the following detailed description is given, merely by way of example, reference being made to the accompanying drawings, in which:- Figure 1 is an elevation partly sectioned somewhat schematic view of a portable cooling tower incorporating one embodiment of fluid distributing apparatus according to the present invention; Figure 2 is a sectioned plan view taken along line 2-2 of Figure 1; Figure 3 is an elevation sectioned view taken along line 3-3 of Figure 2 showing the internal details of the fluid distributing apparatus; Figure 4 is a top plan view of the slinger plate showing the arrangement of the impeller blades thereon; Figure 5 is a bottom view of the slinger plate of Figure 4; Figure 6 is an elevation sectioned view of an alternative embodiment of the invention constructed for use with a downwardly facing fluid outlet; Figure 7 is an elevation sectioned view of another alternative embodiment of the present invention similar to Figure 3 with the addition of a second slinger plate; Figure 8 is a schematic plan view similar to Figure 2 of a larger cooling tower ; Figure 9 is an elevation sectioned somewhat schematic view of a typical prior art portable cooling tower having conventional overhead water distribution grid work with multiple sprinklers; Figure 10 is an elevation sectioned view similar to Figure 6 of an alternative embodiment which has impeller blades on only one side of the rotating disc; Figure 11 is an elevation sectioned view similar to Figure 6 of another alternative embodiment of the invention having an irregular shaped annular surface to define the generally square spray pattern; Figure 12 is an elevation view of the header outlet of the apparatus of Figure 11, showing the irregular annular surface in one profile with a peak of the surface centered in the figure; Figure 13 is a view similar to Figure 12, but rotated 45° about an axis of the header end piece so that a trough of the irregular surface is centered in the figure; Figure 14 is a plan view of the slinger plate of the apparatus of Figure 11; Figure 15 is a bottom view of the slinger plate of Figure 14; and Figure 16 is an enlarged elevation view taken along lines 16-16 of Figure 14 showing a profile of one of the impeller blades. Figure 1 shows a portable cooling tower apparatus 10, similar to that of US-A-4267130 and 4301097 which are incorporated herein by reference. The water distributing apparatus of the present invention can of course also be used in fixed cooling towers such as seen in Figure 8, and further that it can be used in any fluid distributing application including for example lawn sprinklers, pond aeration, and even for moving fluidized solids such as grain. The portable cooling tower 10 typically includes multiple cells each approximately 2.4 meters square in plan view aligned on a trailer framework 13, but Figure 1 shows only a single cell 12 of the apparatus 10. The cooling tower 12 includes frame 14 having four sides 16,18,20,22, which define a rectangular, and in this example a square, framework as best seen in the plan view of Figure 2. Each of the sides include air inlet openings 24 and four layers of corrugated fill material 26,28,30,32, for example 30 cm cube form. The upper end of the framework 14 carries shrouds 34,36 within which are located exhaust fans 38,40, respectively. A collecting basin 42 is located on the trailer 13 below the cooling tower cell 12. A main horizontal pipe header 44 runs the length of the trailer 12 and a vertical pipe header 46 extends upwardly therefrom centrally within the cell 12 and through the layers of fill material 26-32. A pump 48 pumps water from a source 50 through a supply line 52 to the inlet 54 of horizontal header 44, from which it flows up through vertical header 46 and is sprayed outward by a water distributing apparatus 55 as generally indicated by the arrows 56 in Figure 1 to distribute the water uniformly across an upper surface 58 of the uppermost layer 26 of fill material. The exhaust fans 38,40 pull air in through the air inlets 24 and up through the layers of fill material 32,30,28,26, in counterflow to the downwardly flowing water. This cools the water which is then collected in the basin 42 and recirculated or otherwise used as desired. Figure 3 shows details of construction of water distributing apparatus 55, which includes a supply header 60 mounted on the upper end of the vertical pipe header 46. A fluid outlet 66 is defined in supply header 60. Rigidly attached internally within the header 60 is a spider assembly 68, to which a threaded support rod 70 is fixed to extend upwardly through fluid outlet 66. An upper limiting and shrouding structure 72 having a central hub portion 76 which has two threaded nuts 78,80 imbedded therein which are adjustably threadedly mounted upon threaded rod 70 and held in place relative thereto by a lock nut 74. Structure 72 has an upper limit surface 82 defined thereon which is spaced from the fluid outlet 66 of header 60. Located between the fluid outlet 66 and the upward limit surface 82, is a rotatable member 84, which as shown is in the form of a plate, which may be regarded as a slinger plate, deflector plate or a flow divider plate. The member 84 is not limited to flat plates having planar surfaces and can be somewhat irregularly shaped. Impeller means 86 are connected to the slinger plate 84 for rotating it as fluid flows through the fluid outlet 66. The slinger plate 84 has first and second (lower and upper) sides 88,90, respectively, which face the fluid outlet 66 and the upper limit surface 82, respectively. A central opening 92 defined through slinger plate 84 is aligned with the fluid outlet 66 and header 60 has a lower limit surface 94 defined thereon surrounding the fluid outlet 66. Fluid flowing upwardly through the header 60 and up out the fluid outlet 66 splits into first and second streams. An annular first stream flows radially outward between the lower first side 88 of slinger plate 84 and the upward facing lower limit surface 94 surrounding fluid outlet 66. The second stream flows upward through central opening 92 and then spreads into a radially outwardly flowing annular second stream which flows between the second upper surface 90 of limit plate 84 and the downwardly facing upward limit surface 82. The size of the opening 92 in slinger plate 84 relative to the size of fluid outlet 66 affects the proportion of the water in the first and second streams. The impeller means 86 includes first and second sets 96,98, respectively, of impeller blades attached to the lower and upper surfaces, respectively, of the slinger plate 84. The first and second sets of impeller blades are best seen in Figure 5 and Figure 4, respectively. As the two streams of fluid flow radially outward across the lower and upper surfaces 88,90, the fluid is deflected by the impeller blades 96,98 and causes the impeller blades and the slinger plate 84 to rotate. The two sheet-like radially outward flowing streams define a fluid bearing, allowing the slinger plate 84 to rotate free of contact with the header 60 and the limit structure 72. The adjustable positioning of structure 72 upon the threaded rod 70 provides an adjustment of the vertical clearance between the slinger plate 84 and each of the limit surfaces 82,94. As this clearance is reduced, the area for fluid flow therethrough is reduced thus increasing the back pressure on the fluid flowing upwardly through header 60 and causing a radially outward extending spray pattern defined by distributor 55 to be varied. This adjustable orifice is a significant advantage as compared to conventional grid type sprinkler systems (see Figure 9) used in water cooling towers which all have fixed orifices. The water pressure typically supplied to a cooling tower may be as low as 0.07 to 0.20 bar. The prior art nozzle sizes are chosen for a design supply pressure, but if the pressure is reduced the system will work very poorly because the nozzles cannot develop an adequately sized spray pattern. The only solution to reduced pressure with prior art nozzles is to replace the nozzles with other nozzles having a smaller orifice size. The adjustable nozzle of the present invention improves this situation in two ways. First, it can be adjusted as necessary to accommodate supply pressure changes. Second, the fluid distributor of the present invention is much less sensitive to varying pressure because the rotating plate 84 greatly aids in radial distribution of the water even at relatively low pressures. One prototype constructed similar to that shown in Figures 1-3 was tested over a range of supply pressures varying from about 0.07 to about 0.82 bar in an 2.44 by 2.44 metre cell. The radius of the spray pattern which was nominally 1.22 metres at higher pressures dropped by no more than about 0.15 metres when supply pressure was dropped to about 0.07 bar. Thus, the maximum radius of the spray pattern varied approximately 12.5%. It has been found that the spray pattern has a maximum radius which varies no more than 25% over a range of supplied nozzle fluid pressure between 0.07 and 0.82 bar. This fluid distributor can distribute water in a spray pattern having a radius of at least 0.92 metres at liquid supply pressure as low as 0.07 bar. Thus, a single nozzle of the present invention can be used to replace a great many conventional nozzles like those of Figure 9 which typically have a spray pattern with a radius of no greater than about 0.46 metres. The limit surface 82 can limit movement of the slinger plate 84 away from the fluid outlet 66. It will be appreciated, however, that once the apparatus 55 is in operation and the rotating slinger plate 84 has settled into a steady state, it will not actually engage either the header 60 or the structure 72. It will "float" on a water bearing defined by the two sheet-like radially outward flowing annular streams as illustrated in Figure 3. As shown in Figure 3, the lower and upper surfaces 88,90 of slinger plate 84 are flat, whereas the lower and upper limit surfaces 94,82 are somewhat concave, the clearances between these surfaces, in effect defining two nozzles both of which are adjusted when the clearance between structure 72 and header 60 is adjusted. The purpose of this is to make certain that the two radially outward flowing streams can establish themselves so that the slinger plate 84 will "float" between the limit surfaces 94,82 when in operation. Prior to beginning operation of the apparatus 55, the slinger plate 84 will be resting against the header 60. Due to the concave shape of the lower limit surface 94, however, there will be a short vertical clearance between surfaces 94,88 adjacent the fluid outlet 66 thus ensuring that the high pressure fluid exiting outlet 66 will find its way between the slinger plate 84 and the lower limit surface 94 thus establishing the first radially outward fluid stream. Similarly, even if the slinger plate 84 temporarily engages the upper structure 72 when the water is first turned on, the concave shape of surface 82 ensures that there will be a vertical clearance between surfaces 82,90 adjacent the central opening 92, so that the second radially outward flowing stream can establish itself above the slinger plate 84. As seen in Figures 4 and 5, the first and second sets of impeller blades 96,98 are not identically constructed, the lower set 96 being constructed to deflect the first radially outward flowing stream of fluid so that it will fall generally within a radially inner portion 100 of a spray pattern 102 as schematically represented in phantom lines in Figure 2. The upper set of impeller blades 98 is constructed so that it will deflect the second radially outward flowing stream of fluid generally over a radially outer portion 104 of the spray pattern 102. The radially inner portion 100 extends generally from an inner perimeter 106 to an intermediate radius 108, while outer portion 104 extends generally from intermediate radius 108 to outer perimeter 110. There can, of course, be some overlap of the inner and outer portions 100,104 in the vicinity of the intermediate radius 108. The water distributing apparatus 55 sprays the water in the spray pattern 102 extending 360° about a central longitudinal axis 122 of the vertical header pipe 46. This is accomplished by appropriate choice of the shape, size and placement of the impeller blades. For example, the bottom set of impeller blades 96 is made up of a pattern of blades beginning with a shortest bottom blade 112 and increasing in size to a longest bottom blade 114. This pattern repeats over a 180° arc of the bottom surface 88 of plate 84 as seen in Figure 5. Similarly, the upper set of blades 98 seen in Figure 4 includes a repeating pattern which begins with a shortest top blade 116 and increases to a longest top blade 118. Preferably, the longest bottom blade 114 is no longer than the shortest top blade 116. The upper limit and shroud structure 72 includes an umbrella-shaped shroud 120 (see Figure 3) which extends radially outward over and downward towards the slinger plate 84, to deflect the fluid flowing past the slinger plate 84 into a non-circular pattern. Preferably, as best seen in Figure 2, the shroud 120 deflects the fluid into a generally rectangular (square as shown) pattern corresponding to the outer perimeter 110 which generally corresponds to the size and shape of the cooling tower framework 14 as defined by the four sides 16-22. As best seen in Figure 2, the shroud 120 has a cloverleaf shape with four radially protruding leaves, 124,126,128,130 corresponding to the four sides of the generally rectangular spray pattern. Each of the leaves 124-130 extends radially outward and down toward the slinger plate 84 further than intermediate portions 132 of the shroud, so that the spray pattern is deflected downwardly more at those positions adjacent the leaves 124-130 thus bringing the outer perimeter into the generally rectangular shape 110, the fluid distributing apparatus being centrally located within the cooling tower cell 12. As best seen in Figure 3, the outer edge of shroud 120 includes a downwardly turned lip 134 having a plurality of notches 136 cut therein. The purpose of lip 134 is again to aid in knocking down the spray pattern, and the notches 136 still prevent undue interference with the spray pattern. The impeller blades 96,98 of varying length cause water to be deflected to varying radial positions across the spray pattern 102. Since the impeller blades 96,98 also cause the slinger plate 84 to rotate, this causes the water flowing outward along any given radius from the central axis 122 to pulsate radially outward, then back inward, then back outward, etc. This pulsating flow causes the water to be relatively substantially uniformly distributed between the inner perimeter 106 and outer perimeter 110 of the spray pattern 102 across the entire upper surface 58 of the upper layer 26 of fill material. The slinger plate 84 acts as a flow divider which is located between and freely movable between the upper and lower limit surfaces 82,94, to split a stream of fluid flowing out fluid outlet 66 into first and second streams flowing under and over the divider plate 84. The shroud structure 120 is fixed relative to the header 60 during the operation of the fluid distributing apparatus 55 by attachment to support rod 70. Other means of fixing structure 72 and shroud 120 to header 60 could include support arms (not shown) located around the periphery of the shroud 120 and attached to header 60. By way of example, one embodiment of the apparatus 55 has a diameter of outlet 66 of 10 cms, and a diameter of opening 92 in slinger plate 84 of 7.5 cms. That device is constructed for flow rates in the range of from about 1090 to 1454 LPM at a pressure drop of 0.20 to 0.34 bar. The inverted position fluid distributing apparatus 400 shown in Figure 6 includes a supply header 402 connected to a vertical pipe header 404, a downwardly facing fluid outlet 406 being defined in header 402. A spider assembly 408 is attached to header 402 and a downwardly extending support rod 410 extends therefrom to which is threadedly attached limit structure 412, the position of which is fixed relative thereto by lock nuts 414. A slinger plate 416 is located between a lower limit surface 418 defined on limit structure 412 and an upper limit surface 420 defined on supply header 402 adjacent outlet 406. A shroud 422 having a shape substantially like that of the shroud 120 described above is integrally constructed with and extends radially outward and downward from the header 402. The slinger plate 416 has a plurality of upper and lower impeller blades 424,426 attached to its upper and lower surfaces respectively, these impeller blades being slightly modified as compared to those of the apparatus 55 in that they have notches 428 cut in their periphery to reduce the interference with fluid flow while still providing an impeller that will rotate the slinger plate 416 and will adequately deflect the water to the desired radial location. In the view of Figure 6, the slinger plate 416 is again shown "floating" between the upper and lower limit surfaces 420,418, respectively, as it would when in operation with water flowing above and below it. The apparatus 400 will generate a generally rectangular spray pattern just like the pattern 102 described with regard to Figure 2. The use of downwardly directed fluid distributing apparatus 400 will generally be desirable in a cooling tower which is sufficiently large as to require multiple distributors, such as for example in a situation like that shown in Figure 8. When multiple distributors are utilized, it will generally be accomplished through the use of some horizontal pipe headers supplying fluid to each distributor, and it is preferred that those horizontal headers be located above the spray pattern rather than below so as not to interfere with the downwardly dropping spray pattern. Figure 6 also illustrates another aspect of the invention, namely that the two annular surfaces 418,420 can be of different diameters. In the apparatus 400 it is preferred that the lower surface 418 be as small as possible so as to minimize or eliminate any void in the spray pattern immediately below the apparatus 400. Figure 7 illustrates a modified apparatus 300 similar to that of Figure 3, but including multiple slinger plates 84a,84b. The threaded support rod 70 has been lengthened, and a second slinger plate 84b has been added with a spacer hub 302 being slidably centrally located on rod 70 between the two slinger plates 84a,84b. Spacer hub 302 has a downwardly and upwardly facing limit surfaces 304,306 defined on the lower and upper ends thereof, respectively, which function in the same manner as previously described for the other limit surfaces. A central flow passage 308 communicates lower and upper surfaces 304,306. Spider supports 310,312 allow spacer hub 302 to slide freely on support rod 70. Thus, with the apparatus 300 of Figure 7, the fluid flowing upwardly out of fluid outlet 66 will split into four radially outwardly flowing annular streams. The first and second streams will flow across the bottom and top surfaces of the lower slinger plate 84a, while the third and fourth streams will flow across the lower and upper surfaces of the uppermost slinger plate 84b. The shroud 120 will deflect a portion of the fourth stream of fluid flowing across the upper surface of the upper slinger plate 84b thus deflecting it into the desired non-circular spray pattern. It will be appreciated that the impeller blades on each of the lower and upper slinger plates 84a,84b can be configured so as to deflect water over a desired radial portion of the spray distribution pattern. With appropriate sizing, shaping and arrangement of the deflector blades, four generally concentric portions of the radial distribution pattern can be covered by the four streams just described. Due to the greater fluid pressure which will be required to operate a multiple slinger plate apparatus 300, it is anticipated that the apparatus 300 will be more useful in situations such as pond aeration or the like. Typical cooling tower installations only have 0.20 to 0.34 bar available and will preferably use either apparatus 55 or apparatus 400. Figure 8 schematically illustrates the application of the fluid distributing apparatus 55 of the present invention to a larger cooling tower defined by a framework 320. Phantom lines in Figure 8 indicate four quadrants 322,324,326,328 within the framework 23. One of the spray distributing apparatus 400 like that of Figure 6 is located within each of the quadrants so as to cover it in substantially the same manner as illustrated in Figure 2. Figure 10 illustrates another embodiment 400 similar to that of Figure 6. The modifications as compared to Figure 6 reside primarily in the elimination of the upper deflector blades 424 and the change in shape of the lower limit structure 450 which has a conical hub 452 which passes through the central opening 454 of slinger plate 456. Hub 452 is threadedly received on shaft 410 and held in place by lock nut 414. An upward facing lower limit surface 458 is defined on limit structure 450, and has an outer diameter 460 less than an inside diametrical clearance 462 of the lower deflector blades 426. This prevents interference between limit structure 450 and deflector blades 426. The slinger plate 456 is shown in Figure 10 "floating" between limit surfaces 420,458 as it would in operation. The size of opening 454 and of conical hub 452 will affect the annular flow area defined therebetween which will affect the percentage of total flow which will flow across the bottom of plate 456 as compared to that which flows across the top of plate 456. Also the diameters of opening 406, the outside diameter of surface 420, the diameter of opening 454 and diameter 460 of limit structure 450 will affect the upwardly and downwardly directed fluid pressures acting on plate 456. All of those factors together will determine the vertical floating position of plate 456. Experimentation with the shape and dimensions of the various components just mentioned, plus the deflector blades 426 and shroud 422 will affect the pattern of fluid distribution and will show the appropriate choices to achieve a desired fluid distribution in any particular situation. It has been determined that the elimination of the upper deflector blades as shown in Figure 10, and as compared to Figure 6, will cause the plate 456 to float relatively close to upper limit surface 420 and will reduce the relative amount of fluid going to the radially outer portions of the spray pattern. Figure 11 shows another embodiment 500 of the invention, which includes a supply header 502 connected to a vertical pipe header 504. A downwardly facing fluid outlet 506 is defined in supply header 502. A spider 508 is integrally molded with supply header 502 and has a central hub 509. A downwardly extending support rod 510 has a hexagonal head 512 at its upper end which is received in a hexagonal socket 513 molded in hub 509. Rod 510 extends downward through bore 514 of hub 509. A limit structure or deflector plate 516 has a hub 518 with a central bore 520 which slidably receives the support rod 510 therein, a coil compression mechanical spring 522 being disposed about the support rod 510 on a side of the deflector plate 516 opposite the fluid outlet 506. It is held in place by a washer 523 and nut 525. The supply header 502 and deflector plate 516 have first and second annular surfaces 524,526 defined thereon, these surfaces being spaced apart to define an annular nozzle opening 528 therebetween. The first annular surface 524 is an irregular shaped surface shaped so that a vertical spacing between the first and second annular surfaces 524,526 varies around a circumference of said annular nozzle opening 528 to create a non-circular spray pattern of fluid exiting the nozzle opening 528. As is best illustrated in Figures 12 and 13, the irregular shaped first annular surface 524 is an undulating surface having four peaks equally spaced at 90° intervals about the circumference of annular surface 524, and having four troughs located between said peaks and also being substantially equally spaced. One of the troughs is located equidistant between each adjacent pair of peaks. In Figure 12, one peak designated as 530 is oriented on a centre line 532 of supply header 502. Two other peaks 534,536 lie on the left and right edges of the profile seen in Figure 12. The fourth peak is hidden directly behind first peak 530. One trough located between peaks 530,534 is designated as 538. Another trough between peaks 530,536 is designated as 540. In Figure 13, the supply header 502 has been rotated 45° clockwise about its centre line 532 so that now the trough 538 lies on centre line 532. Peaks 534,530 are also visible. As best seen in Figure 11, the irregular shaped first annular surface 524 also is inwardly and upwardly tapered toward the fluid outlet 506. As is apparent in Figures 12 and 13, the undulations formed by the peaks and troughs are of uniform height, so that the annular nozzle opening 528 has four widest spots located between the troughs and the second annular surface 526, and four narrowest spots located between the peaks and second annular surface 526. Thus, a generally square spray pattern will be provided since substantially more fluid will flow through the more open portions of the annular opening 528. Thus, if a single nozzle apparatus 500 is utilized over a square fill area as generally shown in Figure 2, the troughs will be oriented toward the corners of the square. The second annular surface 526 is a uniform frustoconically shaped surface having a radially outermost edge 542 which will lie substantially in a plane. It will be understood, however, that if desired both of the annular surfaces 524,526 could be irregular shaped so as to contribute to the variation in spacing therebetween. With the preferred embodiment illustrated, however, the spacing between the first and second annular surfaces 524,526 will be substantially equal at each of the troughs and at each of the peaks in the first surface 524. A rotating flow divider plate 544 is located between the first and second annular surfaces 524,526 and functions in the same manner as previously described for the other embodiments. A circular central opening 546 is defined through the divider plate 544, which is shown in Figure 11 in a "floating" position as it would be during normal operation. The apparatus 500 includes a plurality of modified impeller blades 548 attached to the plate 544 around the annular nozzle opening 528. Each of the blades 548 extends radially outward beyond an outer edge 550 (see Figure 14) of plate 544 and also extends both above and below the plate 544 to intercept fluid flowing outward both over and under the plate 544. As best seen in Figure 16, each of the impeller blades 548 includes a radially inner serrated edge 552 for atomizing the fluid exiting the annular nozzle opening 528. Further, the significant extent to which the impeller blades 548 extend below the plate 544 in conjunction with the serrated edge 552 provides a means for deflecting some of the fluid exiting the annular nozzle opening 528 below the plate 544 back radially inward toward the longitudinal axis 532 of the annular nozzle opening 528 to eliminate a central void in the spray pattern below the nozzle opening 528 and particularly below the deflector plate 516. The slidable mounting of the deflector plate 516 upon support rod 510, in combination with the compression spring 522 provides an automatic adjusting means for increasing the spacing between the first and second annular surfaces 524,526 in response to an increase in fluid pressure in the annular nozzle opening 528. The apparatus 500 is initially assembled with an axially inner upper end 552 of deflector hub 518 held in abutting engagement with an axially outer or lower end 554 of spider hub 509. This is accomplished by running nut 525 up on threaded bolt 510 to compress spring 522 until spring 522 holds deflector hub 518 against spider hub 509. It will be appreciated that when the fluid pressure supplied to the apparatus 500 is increased, that increased fluid pressure will create an increased downward force acting on deflector plate 516 which will cause the compression spring 522 to be compressed thus increasing the spacing between annular surfaces 524,526. The spring 522 can be generally described as a resilient biasing means 522 for resiliently opposing sliding motion of the deflector plate 516 downward away from the supply header 502. The spring rate of spring 522 can be adjusted by increasing or decreasing the initial compression applied by nut 525. The deflector plate 516 is shown in Figure 11 in an initial position wherein a minimum spacing between the annular surfaces 524,526 is defined by the physical dimensions of deflector plate 516 and supply header 502. When fluid pressure supplied to the apparatus 500 is increased, the increased downward force acting on deflector plate 516 will compress spring 522 to increase the spacing between annular surfaces 524,526. In a typical example, the apparatus 500 will be designed with an initial minimum clearance between surfaces 524,526 at the peaks 530,534,536 of one-half inch. The divider plate 544 will have a thickness of about 6.35 mm thus giving about one-eighth inch clearance above and below plate 544. Spring 522 will be chosen to allow a stroke of about one-half inch so that the maximum clearance between surfaces 524,526 will be about one inch. It will be appreciated that in the absence of the automatic nozzle adjustment provided by spring 522 and the sliding engagement of plate 516 with support rod 510, that a substantial increase in fluid supply pressure would cause the spray pattern to be extended radially outward to an undue extent and would tend to create a void in the centre of the pattern. Conversely, a decrease in flow supply pressure would cause the spray pattern to be reduced radially inward and would tend to create a void in the outer perimeter of the spray pattern. By appropriate choice of the spring rate of spring 522, the nozzle will automatically adjust the cross-sectional area of annular nozzle opening 528 so as to maintain a substantially uniform spray pattern over a wide range of fluid supply pressures and flow rates. Figure 9 illustrates a typical prior art portable cooling tower apparatus like that shown in US-A-4267130 and 4301097, and particularly it illustrates the multiple sprinkler heads such as 330,332,334,336. It will be appreciated that these sprinklers are typically arranged in a grid across both the length and width of the upper surface 58 of the fill material 26. One very significant advantage of the water distributor apparatus of the present invention as compared to prior art apparatus, is that the present apparatus is substantially clog free. It has no small fixed orifices as are commonly present in conventional sprinkler systems. The orifices of the present apparatus are formed by the annular spaces between the slinger plate 84 and the upper and lower limit surfaces 82,94. It will be appreciated that these are relatively very large openings which are unlikely to clog. Furthermore, the rotating slinger plate 84 will serve to dislodge any debris that might flow into those openings. Further, since the slinger plate 84 is freely movable between the upper and lower limit surfaces 82,94, it can be deflected from its normal operating position to allow pieces of debris to be blown outward through the clearances between the slinger plate 84 and the upper and lower limit surfaces 82,94. Another advantage is that the header 60 and the structure 72 and slinger plate 84 can all be made from non-corrosive materials such as fiberglass or injection molded plastic so that it does not corrode. This is another major advantage in the environment of industrial water cooling particularly. Another advantage provided by the centralized fountain-type water distributing apparatus 55, 400 or 500 is that it provides a more uniform distribution of water across the upper surface 58 of the fill material 26 than does a conventional overhead multiple nozzle network like that shown in Figure 9. Yet another advantage is that the only moving part, i.e., the slinger plate 84, "floats" on water bearings and does not contact the other physical components such as header 60 and structure 72, and thus there are no wearable parts. Another major advantage is that the non-circular spray pattern defined by the fixed shroud 120 or by the irregular nozzle spacing of nozzle 500 allows the spray pattern to more uniformly fill the conventional rectangular plan shapes provided by most cooling towers. Again, this improves the efficiency of the tower as compared to a system like that of Figure 9 where an attempt is made to cover a rectangular area with multiple circular patterns which necessarily cannot be efficiently done. Improved uniformity of water distribution across the upper surface 58 of the uppermost layer 26 of fill material may result in a reduction in the number of layers of fill material which is required. Even a reduction from four layers to three will provide very substantial savings in both the manufacturing costs and operating costs of the cooling tower. A reduction in the number of layers of fill material reduces the overall height of the structure thus reducing manufacturing costs and reducing the head which must be overcome by supply pump 48 thus reducing operating costs. The reduced thickness in fill reduces obstruction to air flow, and thus reduces the power requirements for the fans 38,40. Less air flow requirement can also reduce the required height of the air inlet openings 24, thus providing further reduction in the overall size of the cooling tower. Although the apparatus 55, 400 and 500 have been primarily disclosed herein in the context of industrial water cooling towers, it will be appreciated that they may be utilized in many different situations. Other liquids, such as various chemicals, could be handled. Scaled-down versions of the apparatus could be utilized for lawn sprinkler systems. Another application of the water distributor apparatus is for aeration of water such as in effluent treatment ponds or in ponds used to raise catfish or other aquatic creatures. Metallic or ceramic distributors could be constructed for high temperature operation. Further, it will be appreciated that due to its clog-free nature, the fluid distributing apparatus is not necessarily limited to distribution of liquids such as water, but it could in fact be used to distribute fluidized solids such as grain or the like.

Claims: A fluid distribution apparatus comprising first and second structures (60,72,412,422) having first and second spaced surfaces (66,82,418,420), respectively; a rotatable member (84,416) located between said first and second spaced surfaces, the rotatable member and the first and second spaced surfaces defining a dual nozzle including a first annular nozzle outlet defined between the rotatable member (84,416) and the first spaced surface (66,418) and a second annular nozzle outlet defined between the rotatable member (84,416) and the second spaced surface (72,472); a central opening (92) defined through said rotatable member, for conducting fluid to one of said first and second annular nozzle outlets; and means (96,98) for rotating said rotatable member (84,416) as fluid flows out of the dual nozzle, characterised in that said second structure (72,412) is mounted on a support (70,410) connected to said first structure (60,422), said support extending through said central opening (92), so that an annular flow passage is defined between said central opening and said support, to permit lateral mobility of said rotatable member. Apparatus according to claim 1, characterised in that said second structure (72,412) is adjustably mounted on said support (70,410), whereby the spacing between said second surface (82,418) and said first surface (66,420) can be adjusted, thereby adjusting the radial extent of a spray pattern leaving said dual nozzle. Apparatus according to claim 1 or 2, characterised by further comprising automatic adjustment means (512-525) for increasing the spacing between said first and second surfaces, in response to an increase in fluid pressure in said dual nozzle, said automatic adjusting means including a sliding connector (510,520) for connecting said first and second structures, while allowing relative sliding motion between said first and second structures in a direction parallel to a central axis of said annular nozzle outlets; and resilient biasing means (522) for resiliently opposing sliding motion of said second structure away from said first structure. Apparatus according to any preceding claim, characterised in that said rotatable member is dimensioned, relative to said first and second surfaces, whereby the rotatable member rotates, in use, on a fluid bearing without contacting either of said first and second structures. Apparatus according to any preceding claim, characterised in that said first surface is an irregular surface shaped so that a spacing between said first and second surfaces varies around a circumference of said dual nozzle, to create a non-circular spray pattern of fluid exiting said dual nozzle. Apparatus according to claim 5, characterised in that said irregular shaped first surface is an undulating surface having four peaks, substantially equally spaced about said circumference, and having four troughs located between said peaks, said troughs also being substantially equally spaced about said circumference. Apparatus according to any preceding claim, characterised in that said means for rotating said rotatable member comprises vanes (96,98) on at least one surface of said rotatable member facing at least one of said first and second spaced surfaces. Apparatus according to claim 7, characterised in that at least some of said vanes (96,98) have notched or serrated edges (428). Apparatus according to any preceding claim and further comprising an intermediate member (302) positioned between said first and second structures, said intermediate member having one end surface (304) spaced from said first surface (66) and another end surface (306) spaced from said second surface (82), said intermediate member (302) defining a bore (308) therethrough, and wherein there are two rotatable members (84a,84b), located between said surfaces (66,304) and said surfaces (306,82) respectively, said rotatable members rotating independently of one another.

Inventors: CURTIS HAROLD D, CURTIS, HAROLD D.
Applicants: CURTIS HAROLD D, CURTIS, HAROLD D.
Application year: 1992
Main classification: F28F25
IPC codes: B05B1, F28F25, B05B3