Abstract:
A vertical water wall assembly ( 100 ) for generating dynamically changing water patterns in a contained channel ( 114 ) behind a viewing surface. The water wall assembly includes a translucent front sheet ( 110 ) directed toward a viewing space with a rear side containing a multiplicity of concave depressions ( 111 ), and a rear sheet ( 140 ) disposed behind and in proximity to the front sheet that in part acts as a contrasting background. The edges of these sheets are sealed ( 120, 122 ) and water is made to flow in the space defined between the two sheets, entering at the top of the sheets ( 135 ) and exiting at the bottom of the sheets ( 150 ). The flow of water into the water wall at the water inlet ( 125 ) is time varying and is preferably computer-controlled ( 190 ). In operation water flowing in the contained channel ( 114 ) of the water wall takes dynamic, chaotic pathways through the multiplicity of concave depressions ( 111 ). As individual depressions fill and empty, air bubbles that formerly occupied the depressions propagate down the contained channel. This behavior generates a non-uniform “bubbling” sound in the water wall, while contributing to the overall visual effect of the invention.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims priority of provisional application No. 60/422,542, which was filed on Oct. 31, 2002. 

   BACKGROUND OF THE INVENTION 
   This invention relates generally to water fountains and particularly to a fountain for generating dynamically changing water patterns. 
   In the vast majority of prior art water fountains liquid is dispersed over the outer surfaces of fountain elements or streamed via nozzles into the air both with and against gravity. Rarely have water fountains been constructed where the water feature is disposed behind a transparent or translucent surface. As an example of this latter approach Chikazumi (U.S. Pat. No. 5,288,018) teaches a wall fountain with transparent sheets arranged in a zigzag pattern. A series of valves feeding nozzles are turned on and off by a controller to produce a variation of flows constrained by the zigzag sheets. In another example Fuller and Robinson (U.S. Pat. No. 4,715,136) teach a fountain comprised of a transparent plate disposed in opposing relationship to streams of water impinging on the inner surface of the plate; a number of computer controlled proportional valves feeding a number of nozzles provide a kinetic display. Unfortunately, both of these inventions require a complicated and expensive system of valves, nozzles, plumbing and controls to generate a visually dynamic and interesting water display. 
   BRIEF SUMMARY OF THE INVENTION 
   It is a primary objective of this invention to provide a fountain wall assembly wherein dynamically changing water patterns are disposed behind a viewing surface without requiring valves and complicated plumbing. 
   It is a related object of this invention to provide a fountain wall assembly with a translucent viewing sheet whose rear surface is formed with a multiplicity of concave depressions for forming variable pathways for a flow of water. 
   It is a related object of this invention to provide a fountain wall assembly wherein variations in dynamic water patterns are facilitated by variation of the flow rate of liquid supplied to the wall assembly. 
   These and other objects of the invention are met by a water wall assembly for generating decorative patterns on the rear of a translucent viewing surface, comprising, 
   a translucent sheet with an essentially planar front surface and a rear surface having a multiplicity of concave depressions; 
   a backing sheet disposed behind said translucent sheet with means defining a pathway for water to flow in the region between the two sheets from the top of said pathway to an opening in the bottom of said pathway; and 
   supply means for generating a variable flow of liquid to said top of said pathway. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a front elevation view of a first embodiment of a water wall assembly according to this invention. 
       FIG. 2  is a side sectional cutaway view along line A—A in  FIG. 1  showing the internal water channels of the first embodiment of the water wall assembly. 
       FIG. 3  is a sectional view taken along line B—B in  FIG. 1 . 
       FIG. 4  is a partial front elevation view of the pattern sheet of  FIG. 1  taken facing the rear of the pattern sheet and illustrating several pixel-like depressions. 
       FIG. 5  is an enlarged sectional view of several pixel-like depressions taken along line C—C of  FIG. 4 . 
       FIG. 6  is an enlarged plan view of one of the pixel-like depressions in  FIG. 5 . 
       FIG. 7  is a front elevation view of a second embodiment of a water wall assembly according to this invention. 
       FIG. 8  is a side sectional cutaway view along line D—D in  FIG. 7  showing the internal water channels of the second embodiment of the water wall assembly. 
   

   DETAILED DESCRIPTION 
     FIG. 1  shows a front elevation view of a first embodiment of water wall assembly according to this invention.  FIG. 2  shows a side sectional view of the wall assembly taken along line A—A in  FIG. 1 . By reference to both figures, wall assembly  100  is comprised generally of base plate  124  with water inlet  125 , front pattern sheet  110 , middle reflecting sheet  142 , rear sheet  140 , pattern sheet retainers  120  and  122 , top outlet cover  115  and top plate  130 . Water from dynamic water supply means  190  enters the wall assembly at inlet  125 , which is coupled to an opening in rear plate  140  via inlet housing  145 . One example of dynamic water supply means  190  is a computer-controlled pump with time varying output flow rate. 
     FIG. 3  is a sectional view taken along the line B—B in  FIG. 1  looking toward the top of wall assembly  100 . By reference to  FIG. 2  and  FIG. 3 , rear sheet  140  and middle reflecting sheet  142  define a channel  160  for water to flow from water inlet  125  to the top slot opening  135  in  142 . The depth of this channel is defined by the thickness of separator strips  155  and  156  in  FIG. 3 . For small tabletop fountain displays the depth of channel  160  can be slightly less than the width of pattern sheet  110 . Pattern sheet  110  is a transparent or slightly translucent sheet with a planar front surface  111  facing the viewer and a rear surface  112  defined by a plurality of contiguous concave depressions. For different visual effects in terms of the contrast between pattern sheet  110  and middle reflecting sheet  142  when water flows in channel  160 , the percentage of light transmission of pattern sheet  110  is preferably between 70% and 100%. Pattern sheet  110  can be cast, extruded or injection molded in acrylic or styrene, or polyester resin as appropriate. The degree of translucency of pattern sheet  110  can be controlled by controlling the surface finish of the mold or die used in its manufacture. 
   Alternatively, while not shown in the figures, pattern sheet  110  can consist of a transparent front glass plate with a cast plurality of contiguous concave depressions bonded to its rear surface. In this case, the resulting “sandwich” is rigid and will resist buckling when the width and height of the water wall are large. 
   Middle reflecting sheet  142  is preferably opaque in this embodiment. By reference to  FIG. 1  and  FIG. 2 , pattern sheet  110  has a front planar side, which faces the viewer and a rear patterned side comprised of a multiplicity of pixel-like depressions. As shown in  FIG. 3 , the planar side of  110  is affixed to the underside of the lips of pattern sheet retainers  120  and  122 . The depth  172  of the leg portions of retainers  120  and  122  is preferably slightly greater than the thickness  118  of pattern sheet  100  (see  FIG. 5 ). The resulting channel  114  defined by the region between the front surface of middle reflecting sheet  142  and the rear surface  112  of  110  forms an internal pathway for water exiting top slot  135 . This is preferable when the water wall is relatively small—for instance where the width and height of the water wall is less than approximately 16″ by 24″, respectively. Alternatively, for large water wall assemblies the depth  172  of the leg portions of retainers  120  and  122  is preferably equal to the thickness  118  of pattern sheet  110 . In this case the rear or pattern sheet  110  will be in contact with the front surface of middle reflecting sheet  142 . Liquid will then be constrained to the valleys in the multiplicity of depressions in pattern sheet  110 . In fact to prevent pattern sheet  110  from buckling under water pressure, for example if it is cast in relatively thin acrylic or styrene, it is preferable to fixedly adhere the multiplicity of peaks  180  through  184  (see  FIG. 5 ) to the front surface of middle reflecting sheet  142 . 
   Pattern sheet  110  can better be understood by reference to  FIG. 4  through  FIG. 6 . 
     FIG. 4  shows a partial front view of a portion of pattern sheet  110  with the pixel-like concave depressions uppermost. These depressions are preferably hemispherical and are oriented at 45-degrees to section line B—B in  FIG. 1 . 
     FIG. 5  shows an enlarged sectional view along line C—C of  FIG. 4  illustrating several of the pixel-like depressions in cross section. 
     FIG. 6  is an enlarged plan view of one of these pixel-like depressions in  FIG. 5 . As shown in  FIG. 6  and by reference to  FIG. 4 , the borders of each contiguous depression with its neighboring depressions form a multiplicity of peaks  180 ,  181 ,  182 , and  183 . These peaks together with their corresponding enclosed depressions form a multiplicity of contiguous “pixels”. With sheet  110  as shown in  FIG. 4 , these “pixels” are analogous to the pixels on a computer screen. 
   Now consider that a viewer is facing the front planar side of pattern sheet  110  and further consider an arbitrary pixel  185  in  110 . If this pixel and the intervening space between the pixel and the front surface of  142  are water filled, the water will act as an index matching fluid; this will allow most of the light incident on front surface  111  of  110  to be transmitted to the front surface of  142  thereby allowing the surface of  142  behind the pixel to show clearly through  110 . If on the other hand, there is no water behind the pixel and  142 , then more light will be locally scattered and reflected by it than if the region were water filled. The maximum contrast between pixels that are water filled and pixels that are air filled is attained if the front surface of  142  is black and pattern sheet  110  is slightly translucent. Advantageously, the difference in the index of refraction of air and water facilitates the development of a highly decorative dynamic water display. 
   The operation of wall assembly  100  shall now be discussed. Water from supply means  190  is supplied to inlet  125 , flows upward in channel  160 , exits through slot opening  135 , falls in internal channel  114  and exits at opening  150  in base plate  124 . Water can also exit via gap  116  onto base plate  124 . As an alternative—not affecting the operation, described below, of the water wall—slot  150  can be sealed. Water will then solely flow over the surface of  124  via opening  116  at the base of  110 . A slot can then be provided at an arbitrary location on  124  to facilitate drainage of the base plate or water can be allowed to run over its sides for decorative effect. As another alternative, gap  116  can be closed so that all water exiting the wall now flows through base plate  124  to effect an essentially sealed fountain. 
   Consider that means  190  outputs water with fixed flow rate f&gt;0. After an initial lag where water fills channel  160 , water will begin to flow from slot  135  into channel  114 . As it does so, water will displace the air in each of the concave depressions in  110  that it reaches. In fact for any fixed flow rate high enough to allow water to flow from  135 , a steady state pattern will develop in channel  114 . If f is high enough, water will eventually completely fill channel  114  and all of the depressions (“pixels”) in  110 . 
   Now consider that the flow rate from means  190  is made to vary dynamically over time within the range 0≦f&lt;f max  where f max  is such that channel  114  is fully filled in steady state. Each change in flow rate great enough to allow water to flow down  114  causes variation in the filling of channel  114 . As this occurs, dynamically changing patterns will evolve over pattern sheet  110 . Since water falling down channel  114  instantaneously takes the path of least resistance, the sequence of water paths will be chaotic. The multiplicity of peaks and valleys in the rear surface of  110  contributes to this chaotic effect. Further, the 45-degree orientation of the peaks  180 – 184  (see  FIG. 5 ) relative to section line D—D in  FIG. 1  contributes to this chaotic effect by laterally diverting the downward flow of water. 
   Advantageously, as supply means volume is varied and individual pixel-like depressions are filled, air bubbles that formerly occupied these depressions are displaced and propagate down channel  114  until they exit the wall. This phenomenon generates a pleasing non-uniform “bubbling” sound while adding to the visual effect of the invention. 
     FIG. 7  shows a front elevation view of a second embodiment of a water wall assembly  200  according to this invention intended for large fountain displays.  FIG. 8  is a side sectional cutaway view along line D—D in  FIG. 7  showing the internal water channels of this second embodiment. By reference to  FIG. 8 , tube  310  communicates with an internal water reservoir which supplies a distributed volume of water to the water wall. This water reservoir is defined by reservoir base  320 , rear sheet  300  and middle sheet  242 . Water enters the wall assembly via coupling  330  in direction  205  and flows via tube  310  to the reservoir. Diverter plate  335  in the reservoir extends perpendicularly over the outlet of tube  310  to facilitate uniform water distribution along the horizontal extent of the reservoir. The top lip of middle sheet  242  acts as a spillway for water to enter channel  214 . For small water walls, the effective width of channel  214  is preferably substantially the same as that of channel  114  in the first embodiment of the invention. For large water walls the rear of pattern sheet  210  is preferably butted against the front of middle reflecting sheet  242  as described in the first embodiment. In this case, liquid will be constrained to the valleys in the multiplicity of depressions in pattern sheet  210 . 
   As in the first embodiment, gap  216  at the base of the water wall can be sealed. Note that in  FIG. 8  the base of channel  214  is open, thus allowing liquid to exit downward. By then providing a slotted opening at the base of a floor or support structure on which the water wall is to be installed, the water wall can be made to drain directly to a hidden reservoir not visible to those viewing the water wall. This alternative draining method has no effect on the operation of the water wall of embodiment two, said operation being identical to that of the first embodiment. 
   Other embodiments and changes to the invention can be considered. First, instead of the hemispherical depressions in pattern sheet  110  as shown in the figures, other arrangements of contiguous or non-contiguous concave depressions could alternatively be specified for pattern sheet  110 . For instance a pattern of diamond or cylindrical shaped depressions could be specified. These would change the look of the display when in operation but would not change the basic manner in which the display functions. 
   Second, although not shown in the figures for the first embodiment of the invention, diverter strips can be variously disposed in channel  160  to modify the distribution of flow across slot  135 ; this may be desirable when the ratio of the height of pattern sheet  110  to its width is low. 
   Third, for water walls large in height and width, multiple supply tubes could be disposed along the width of the rear of the wall assembly in the second embodiment to reduce turbulence over that in the case of employing a single tube ( 310 ) as shown in  FIG. 8 . 
   Fourth, a rear-illuminated embodiment of the invention can be considered. As an example, middle reflecting sheet  142  ( 242 ) could be translucent and edge lit. Alternatively, sheets  142  ( 242 ) and  140  ( 300 ) could be translucent with lighting means suitably disposed to achieve the same effect. 
   Fifth, a multiplicity of water walls according to this invention can be disposed in a pattern, each driven by separate supply means. Further, these supply means can be synchronized to provide a coordinated display. 
   Sixth, a wall hanging water wall can be made wherein the operation is identical to embodiments one and two, however having inlet and outlet means that communicate with a reservoir containing pump means. This reservoir can be a structure integral to the rear of the wall in  FIGS. 7 and 8 . Alternatively, the reservoir can be disposed remotely from where the hanging water wall is to be installed. 
   Although there has been shown and described hereinabove a specific arrangement of a fountain assembly for generating decorative patterns in accordance with the invention for the purpose or illustrating the manner in which the invention may be used to advantage, it will be appreciated that the invention is not limited thereto. Accordingly, any and all modifications, variations, or equivalent arrangements, which may occur to those skilled in the art, should be considered to be within the scope of the invention.