Abstract:
A water distributor provides a uniform supply of water to an evaporative panel held in a frame of an evaporative apparatus. The water distributor includes a base having a plurality of flow channels, each of the flow channels having an inlet port for receiving water from a source, an outlet port for delivering water to the evaporative panel and a tortuous path connecting the inlet port with the outlet port for providing high flow resistance so as to facilitate the consistent and even flow of water through each of the outlet ports. The volumetric flow velocity of the water is controlled within a desired range at normal water supply pressures.

Description:
FIELD OF THE INVENTION 
     This invention relates broadly to apparatus for contacting large surfaces of a liquid, such as water, with a gas, such as air, for the purpose of humidifying air. More particularly, it refers to an improved means for the uniform distribution of water to an evaporative element in such an apparatus. 
     BACKGROUND OF THE INVENTION 
     The humidification of dry air normally occurring in buildings during the winter heating season by the evaporation of water therein, depends upon the efficient evaporation of water from the continuously wetted surfaces of an evaporative element or pad as, for example, an interstitial body having extensive surfaces to provide a large area of contact of the air with water. The air to be humidified is forced through the openings of the element where it contacts the wet baffles or fibers of which the evaporative element is composed. Exposure of relatively large water surfaces in this way results in the evaporation of large amounts of the water. 
     An example of this type of evaporating apparatus is disclosed in the assignee&#39;s U.S. Pat. No. 5,211,891 issued May 18, 1993. In this apparatus, the humidifier includes a base portion and a removable cover. An evaporative pad or water panel is removably disposed within the base. A water feed tube is connected to a solenoid valve equipped with a small orifice for controlling the flow of water therethrough and supplies water to a trough-like distribution tray. The water flows by gravity from the distribution tray through openings and down through the water panel. Air is forced through the water panel and the air evaporates water on the water panel and humidified air is delivered to the house, building or heated space. The evaporative water panel is held within a frame mounted in the base portion in order to reduce the air bypass around the water panel, and to contain mineral deposits that build up on the water panel as a result of the evaporative process. 
     A typical prior art distribution tray is a plastic reservoir 0.875 inches deep which spans the top of a water panel. Within the reservoir are six cylindrical towers with V-shaped metering weirs intended to evenly spread the water to six places on the top of the water panel. The interior of this distribution tray is coated with a spray adhesive and pumice powder in the hopes of improving the evenness of the water metering. This pumice coating process is a very undesirable manufacturing step. It is labor intensive, messy and very hard toontrol, so that the coating evenly cogs all parts. When the coating is not uniform, the metering rate of individual weirs is not equal. By design, the distribution tray must be relatively large to contain an adequate water level for the metering weirs to function. This directly effects the cost of the part and indirectly the cost of the humidifier as a whole since the humidifier must be sized to contain the distribution tray. This larger size effects versatility in installation of the humidifier, since more space is required. 
     Another critical problem arises during installation. Weir-type metering systems are very sensitive to being mounted level. That is, the plane of the upper surface of the distribution tray should be parallel to the earth&#39;s horizon. If mounted at an angle, water will be deeper at one weir than the others and water flow will be uneven. In some cases, all the water may flow out only the lowest weir. Non-uniform shape of the individual metering weirs is another major problem. In manufacture, the weir is effected by molding flash, trimming of flash, warpage of plastic, and uneven coating of pumice. In actual use, mineral deposits may change the shape, cleaning can scrape away some of the pumice coating, or the pumice coating erodes away in some water conditions. When the metering weir is not uniform, water is not evenly distributed to the water panel. Another problem with the prior art distribution tray is its slow response time. When the humidifier turns on, it takes about 30 seconds for enough water to fill the distribution tray for the metering weir to begin supplying water to the water panel. Yet another problem is that the metering forces of a weir design are very low and easily disturbed to cause uneven flow. The operating pressure from the reservoir water level is only about 0.014 psi when all six weirs are functioning. This low pressure is within a realm of molecular water forces such as surface tension and capillary force. The metering rate is thus easily disturbed. When one weir does not start or stops flowing, the reservoir water level rises slightly and flow diverts to the remaining weirs. The pressure increase on the blocked weir is only about 10%, so there is very little force increase to encourage the weir to restart. Even if all but one weir is blocked, the pressure increases to only about 0.033 psi, still not enough to encourage blocked weirs to restart. 
     All of the above problems degrade the performance of humidifiers. Evaporation from the humidifier water panel is best when it is evenly covered with an adequate supply of water. Uneven distribution of water can lead to loss of wetted surface in the water panel and reduced evaporation. 
     Most competitor humidifiers are using variations of the weir. Different weir shape, placement, and materials are used. Some use surface textures or die cut wicking materials in place of pumice coating. All of these have the same drawbacks as the systems described above. One design lets the water stream from a single nozzle drop onto a series of ribs which divide the flow and guide each resulting stream to an outlet hole. This method takes up about the same space and has part costs similar to the prior art system. It also has low control forces and flow might easily be made to distribute unevenly. Other competitors avoid the distribution system by dipping the evaporator media in a reservoir. Stationary versions rely on wicking ability of media. These are not currently used on furnaces and performance is weak unless a recirculating pump is added with a high flow rate distributor. Dynamic systems form evaporator media in a wheel or drum shape that rotates through a reservoir to wet out. These are undesirable due to mechanical complexity and added cost. 
     Accordingly, it is desirable to provide a water distributor for humidifiers or other similar evaporative apparatus which overcomes the numerous problems and drawbacks set forth above. It is also desirable to provide a humidifier which replaces the prior art distribution tray, and provides a better water distribution to the evaporative water panel. 
     SUMMARY OF THE INVENTION 
     It is one object of the present invention to provide a water distributor which eliminates the prior art trough-like distribution tray and pumice coating thereof. 
     It is also an object of the present invention to provide a water distributor which enables a consistent, even flow of water at a desired flow rate therethrough and a quicker response time in which water is delivered to the evaporative water panel. 
     It is a further object of the present invention to provide a water distributor which is capable of unplugging flow blockages caused by particles in the incoming water flow. 
     It is an additional object of the present invention to provide a water distributor employing tortuous flow channels designed for high flow resistance. 
     Another object of the present invention is to provide a water distributor which is improved in unit size, cost and manufacturability. 
     Yet a further object of the present invention is to provide a water distributor which is insensitive to unlevel mounting angles in the humidifier. 
     In one aspect of the invention, a water distributor provides a uniform supply of water at a desired flow rate to an evaporative panel held in a frame in an evaporative apparatus. The water distributor includes a base having a plurality of flow channels, each of the flow channels includes an inlet port for receiving water from a source, an outlet port for delivering water to the evaporative panel, and a tortuous path connecting the inlet port with the outlet port to provide high flow resistance, so as to facilitate the consistent and even flow of water through each of the outlet ports. The base is comprised of an elongated, planar manifold and an elongated planar cover interconnected thereto. The water inlet is in communication with the water source and a header structure is in communication with the water inlet in each of the inlet ports. Each flow channel is configured in the shape of a square or star-shaped wave. The base is attached to the evaporative apparatus such that the outlet ports are positioned over the evaporative panel. A solenoid valve is interconnected with a water inlet fitting and the water inlet. In several of the embodiments, the base is attached to bosses depending from the evaporative apparatus. In another embodiment, the base has tabs formed thereon and the frame is formed with slots for receiving the tabs such that the base is supported from the frame. 
     In another embodiment, the base is provided with a tubular inlet extending from the water inlet. In yet another embodiment, a solenoid valve and water inlet assembly is attached directly to the base in communication with the water inlet. Yet another embodiment discloses a base which is provided with a filter and includes a groove for receiving an O-ring positioned between the water inlet and the water inlet fitting. 
     In another aspect of the invention, a water distributor is adapted to feed water uniformly at a controlled flow rate to an evaporative panel located therebelow. The water distributor includes a manifold having a length, a width and a thickness, and a water inlet at one end thereof, header structure in communication with the water inlet and extending along the length of the manifold, and an array of flow channels. Each of the flow channels has an inlet port connected with the header, an outlet port for delivering water to the evaporative panel and a tortuous path interconnecting the inlet port and the outlet port. A cover is attachable to the manifold. With this construction, water is supplied to the water inlet, the header structure and each of the inlet ports, flows with high resistance through each of the tortuous paths, and is delivered with a consistent and even flow at a controlled flow rate dependent on water pressure to each of the outlet ports for deposition onto the evaporative panel. The manifold and the cover are formed from a plastic material. Preferably, the array of flow channels is a group of six flow channels. In one embodiment, the array of flow channels is aligned in parallel. In another embodiment the array of flow channels is arranged in alternating fashion with some of the flow channels on one side of a longitudinal axis, and the other of the flow channels on the opposite side of the longitudinal axis, each of the outlet ports extending vertically through the thickness of the manifold. In several of the embodiments, each of the outlet ports are located along a side edge of the manifold. In some cases, a throttle resistor structure interconnects the water inlet with the header structure to improve control of flow rate. It may be that the throttle structure may take the form of an orifice upstream from the water inlet. In at least one embodiment, the cover and manifold are provided with a cooperating locator pin and hole arrangement. Also in another embodiment, the cover is integrally formed with a solenoid valve body receiving a stack of solenoid components. The cover and stack of solenoid components are retained together to form an assembly. The flow channels may take the form of a square or star-shaped wave. 
     Various other features, objects, and advantages of the invention will be made apparent from the following description taken together with the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     The drawings illustrate the best mode presently contemplated of carrying out the invention. 
     In the drawings: 
     FIG. 1 is a cross sectional view of a Prior Art humidifier; 
     FIG. 2 is a perspective view of a Prior Art evaporative water panel, frame and distribution tray used in the humidifier of FIG. 1; 
     FIG. 3 is an exploded view of a Prior Art water supply circuit as used in the humidifier of FIG. 1; 
     FIG. 4 is a plan view of a manifold of a water distributor embodying the present invention; 
     FIG. 5A is an exploded, perspective view of a water distributor employing the manifold of FIG. 4; 
     FIG. 5B is a cross sectional view of the mounting of the water distributor of FIG. 5A in a humidifier; 
     FIG. 6A is an exploded, perspective view of a first alternative embodiment of the water distributor; 
     FIG. 6B is a perspective view showing the mounting of the water distributor of FIG. 6A and a water panel frame; 
     FIG. 6C is a cross sectional view taken on line  6 C— 6 C in FIG. 6B; 
     FIG. 7A is an exploded, perspective view of a second alternative embodiment of the water distributor; 
     FIG. 7B is a perspective view of the mounting of the water distributor of FIG. 7A in a humidifier; 
     FIG. 8A is an exploded, perspective view of a third alternative embodiment of the water distributor; 
     FIG. 8B is an assembled view of the water distributor of FIG. 8A; 
     FIG. 8C is a cross sectional view taken on line  8 C— 8 C of FIG. 8A; 
     FIG. 9A is an exploded, perspective view of a fourth alternative embodiment of the water distributor; 
     FIG. 9B is a cross sectional view of the water distributor of FIG. 9A in an assembled form; 
     FIG. 10 is a plan view of a fifth alternative embodiment used in the water distributor; and 
     FIG. 11 is a plan view of a sixth alternative embodiment used in the water distributor. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Prior Art 
     Referring to FIG. 1, a Prior Art humidifier  10  includes a base portion  12  and a removable cover  14 . Base portion  12  is connected to a warm air plenum  16  of a furnace system. A power cord  18  is connected through the bottom of the cover  14  and provides 120 volt AC power which is typically stepped down to 18 to 24 volts AC. An evaporative pad or water panel  20  is removably disposed within the base portion  12 . A water feed tube  22  is connected to a solenoid valve  24  and supplies water via a nozzle  26  to a trough-like distribution tray  28 . The water flows from distribution tray  28  through discharge openings  30  and down evaporative water panel  20 . Air is forced through evaporative water panel  20  by a fan  32  driven by an electric motor  34  so as to evaporate the water on the panel  20 . The humidified air is then delivered to the house, building, or heated space. Evaporative water panel  20  is held in a frame  36  within the base portion  12  in order to reduce the bypass around panel  20  and to contain the mineral deposits that build up on panel  20  as a result of the evaporative process. 
     As seen in FIG. 2, the Prior Art evaporative water panel frame  36  includes a pair of spaced apart side walls  38 , an integral bottom portion  40  disposed between side walls  38 , and a removable top portion  42 . Bottom portion  40  is provided with a drain opening  44  through which excess water from the water panel  20  can be drained. Top portion  42  includes distribution tray  28  and its discharge openings  30  which are generally equally spaced therein. The length of the distribution tray  28  is substantially equal to the top edge of evaporative water panel  20 . Discharge openings  30  are provided with V-shaped notches or weirs  46  formed by cylindrical risers  48 . The weirs  46  are intended to evenly spread the water along the tops of the evaporative panel  20 . The interior of the distribution tray  28  is typically coated with a spray adhesive and pumice powder for improving the evenness of water metering. 
     FIG. 3 illustrates an exploded view of a Prior Art water supply circuit used in humidifier  10  and comprising solenoid valve  24 , feed tube  22 , nozzle  26  and distribution tray  28 . Solenoid valve  24  includes a first nut  54 , a brass sleeve  56 , a strainer  58 , an upstream fitting  60 , a downstream fitting  62 , a plastic sleeve  64 , a second nut  66 , and a small diameter orifice  68  which is positioned in the lower end of feed tube  22 . It is this orifice  68  which regulates a low volume water flow rate to the distribution tray  28 . 
     As set forth in greater detail in the Background of the Invention, uneven distribution of water from distribution tray  28  can lead to loss of wetted surface in the water panel  20  and further reduced evaporation. It is the present invention which eliminates the pumice coating of humidifier components, and markedly improves the design of the distribution tray  28  to provide better water distribution to and evaporation from the water panel  20 . 
     The Present Invention 
     In one embodiment, the distribution tray  28  is replaced by a water distributor manifold  70 , FIG. 4, typically in the form of a flat, rectangular plastic bar or plate, such as acrylic, measuring, for example, ten inches in length, one inch in width, and three-sixteenth inches in depth. The plate  70  has a feed tube or water inlet entrance  72 , an optional throttle resistor  74  and a series or array of spaced apart, flow channels  76  formed therein such as by machining or molding. Water delivered through entrance  72  is introduced to the throttle resistor  74 , a bent passageway of tortuous construction designed to partially drop the water system line pressure of 40 to 60 psi about 75%, so that the flow channel  76  will fit on the one inch wide bar. The throttle resistor  74  has a larger passage than a prior art orifice  68  so that the risk of particle blockage is lower and the orifice  68  is eliminated. Upon exiting the throttle resistor  74 , the water enters an elongated header  78  which runs substantially along the length of the bar  70 . The header  78  supplies water to six parallel, identical flow channels  76 , each of which is made with an inlet port  80  in communication with a square wave, tortuous path  82 , so that flow resistance is high and the flow rate of the water is controlled even though the cross sectional area of the flow channel  76  is greater than the prior art orifice  68 . This design is intended to allow easier manufacture of parts that provide substantially consistent and even water flow from an outlet port  84  in each flow channel  76 . Each outlet port  84  opens to one side of the manifold  70 . The manifold  70  with its flow channels  76  provides a water circuit plate. It should be understood that the tortuous path  82  in each flow channel  76  is not limited to a square wave path, but may be formed of various shapes which may provide more turbulence in a shorter path or allow larger channel cross section. If size of the manifold  70  is not limiting, it is not necessary to have a throttle resistor  74 . That is, in its broadest form, water supplied through entrance  72  flows directly into header  78  and into flow channels  76 . 
     Turning to FIG. 5A, the manifold  70  may be formed with locator holes  86  for receiving cooperating pins  88  formed on the bottom of a flat, rectangular plastic cover plate  90  which is secured such as by epoxy bonding, over the flow channels  76  and the flow manifold. Cover plate  90  includes a deflector lip  91  so that water will exit outlet  84  as downward drips of water not as a small jet at a normal flow rate. The combination of the manifold  70  and the cover plate  90  forms an elongated, planar base and defines a water distributor  92  embodying the present invention. Aligned holes  94  are provided in both the manifold  70  and cover plate  90  for receiving fasteners  96  used to attach water distributor  92  to the top of frame  36 . Cover plate  90  is provided with a tubular inlet  100  which connects feed tube entrance  72  with the feed tube  22  in a pressure type connection  101 . 
     One alternative embodiment to the water distributor  92  is shown in FIGS. 6A,  6 B and  6 C, which illustrate a manifold  70   a  having a feed tube entrance  72   a , flow channels  76   a  and a pair of parallel depending air bypass flanges  102  for retaining the top edges of evaporative water panel  20  in frame  36 . Both the manifold  70   a  and cover plate  90   a  forming water distributor  92   a  are provided with end tabs  104  adapted to fit in slots  106  formed in side walls  38  of frame  36 . A brass fitting  108  is used to interconnect feed tube  22  with feed tube entrance  72   a  located in a laterally projecting ear  110 . 
     A second alternative embodiment shown in FIGS. 7A and 7B is comprised of a water distributor  92   b  having solenoid valve  112  and water inlet fitting  114  mounted directly thereon with a rubber gasket  116  seated in the feed tube entrance  72   b , and a pair of screws  118  passing through holes in the water distributor  92   b  and holes in gasket  116  and holes at the bottom of the fitting  114 . The combination water distributor/solenoid valve assembly is installed in the interior or top of the humidifier base portion  12  by passing a pair of screws  120  through mounting holes  122  in the corners of the water distributor  92   b  and into the bosses  124  formed on the base portion  12 . A hole  126  is formed in the side wall of the base portion  12  for reception of the water inlet  127  on fitting  114 . This is a particularly attractive embodiment in which direct mounting of the solenoid valve  112  and water inlet fitting  114  to the water distributor  92   b  eliminates the prior art feed tube  22 , nozzle  26 , orifice  68 , brass fitting  62 , plastic sleeve  64  and nut  66 , and thus saves cost and reduces points of potential leaks. This design results in less costs in humidifier housing, packaging and shipping and allows installation in tighter spaces. 
     A third alternative embodiment illustrated in FIGS. 8A,  8 B and  8 C, combines the concept of mounting the solenoid valve  112  directly to the water distributor  92   c  with the concept of molding a portion  132  of solenoid valve  112  directly into the distributor cover plate  90   c . As seen in FIG.  8 A. the cover plate  90   c  includes an integrally molded valve body  132  having a laterally projecting water inlet  134  leading to a water source. Cover plate  90   c  is joined such as by solvent welding to manifold  70   c  with flow channels  76   c . The valve body  132  receives in stacked formation, O-ring  138 , spring  140 , plunger  142 , core  144 , over-molded coil  146  and a nut  148 . 
     A fourth alternative embodiment shown in FIGS. 9A and 9B addresses the problems of large particles shed from the solenoid valve  112  which have a tendency to clog the water distributor  92   d . Such particles, typically comprised of brass, rubber, steel or plastic, are created during part machining or from friction during assembly. Dirt may also enter parts from handling during assembly or shipping. In this version, the cover plate  90   d  is provided with an O-ring groove  150  which surrounds a conventional, circular particle filter  152  having holes smaller than those forming the flow channels  76   d . Filter  152  is placed in an opening  153  formed in cover plate  90   d , the opening  153  being in communication with header  78 d on manifold  70   d . Filter  152  captures any residual particles exiting from the solenoid valve  112 /water inlet fitting  114 . With the cover plate  90   d  secured in position, O-ring  138  is placed in the groove  150 . Solenoid valve  112 /water inlet fitting  114  has an outlet on the bottom thereof which is placed over the O-ring  138  and filter  152  and fastened by a pair of screws  154  which pass through the water distributor  92   d  and are threaded into the base of the solenoid valve assembly  112 , 114 . 
     A fifth alternative embodiment is shown in FIG.  10  and further addresses the problem of internal blockage due to particles from the solenoid valve assembly. In this design, manifold  70   e  is divided into two independent groups of ports. More particularly, the inlet from the solenoid valve assembly  112 , 114  is split into two opposed throttle resistors  74   e  and into respective headers  78   e  on each side of the manifold  70   e . One header  78   e  feed three inlet ports  80   e , flow channels  76   e  and outlet ports  84   e  on one side of manifold  70   c . The other header  78   e  feeds an additional three inlet ports  80   e , flow channels  76   e  and outlet ports  84   e  which are located on the other side of the manifold  70   c  and are interspaced in alternating fashion from their companion inlet ports  80 e, flow channels  76   e  and outlet ports  84   e . With this construction, the chances of two throttle resistors  74   e  becoming blocked is lower than one resistor. Outlet ports  84   e  of each group extend vertically through the manifold  70   e  and are interposed so water is still delivered to most of the water panel  20  if one group becomes blocked. The outlet ports  84   e  have larger diameter holes than the flow channels  76   e  so as to break down the jet exiting the flow channel  76   e  into lower velocity drips. 
     In each embodiment described above, water delivered to the feed tube entrances  72   a-e  passes through the resistor structure  74   a-e  (if any), and header structure  78   a-e , and then flows into the inlet port  80   a-e  of each flow channel  76   a-e  along the particular tortuous path  82   a-e . The resulting water flow to each of the outlet ports  84   a-e  provides an adequate water supply which is directed onto the top of the water panel  20  and flows downwardly to evenly cover the panel  20 . Air is forced by a motor-driven fan  32  through water panel  20  so as to evaporate the water in the panel  20  and deliver humidified air to the surrounding building structure. 
     With the water distributor  92   a-e  of the present invention, the flow channels  76   a-e  have small volume. As a result, water distribution is obtained nearly instantaneously as soon as the humidifier  10  is turned on, whereas the prior art humidifier with distribution tray  28  took about thirty seconds to fill before water would flow to the water panel  20 . 
     It should also be appreciated that the flow channels  76   a-e  are molded or machined accurately in a plastic component resulting in uniform flow from each outlet port  84   a-e . Since each outlet port  84   a-e  operates at line pressure, the control force is several orders of magnitude higher than other influencing forces such as water depth, surface tension, and capillary force. This results in uniform output no matter what orientation the distributor  92   a-e  is mounted in. Installer care would be less important in humidifier performance. Because resistance develops in a long path, the cross sectional area of the flow channels  76   a-e  is many times that of a traditional orifice with small hole. It is less likely a particle will block the channel. Since the design allows many independent flow paths, total blockage of water is less likely and water flows remains more even. If one port of the new concept is blocked, the pressure and flow rate of the other ports remains constant and most of the humidifier performance is retained. Unlike the prior art distribution tray, there is some potential that a blocked port will reopen. As mentioned above, when a weir stops flowing, very little pressure builds to restart it. In the present invention, if a blockage would occur in the flow channel  76   a-e , or maybe mineral deposits begin to block the outlet port  84   a-e , full line pressure will build up behind the blockage and may reopen the flow channel  76   a-e . All of these advantages result in a more reliable and uniform water flow to the water panel and better humidifier performance. 
     It should likewise be understood that there are many ways to shape the tortuous path, flow channels  76   a-e  so as to provide more turbulence in a shorter path or allow larger flow channel cross section. With respect to the manufacturing of the water distributor  92   a-e , injection molding thermoplastic appears to be a preferred manufacturing method. However, other methods such as thermoforming may be possible. Joining the components may be by mechanical screws or rivets with a gasket between parts or direct bonding via solvent or ultrasonic welding, tape adhesive bonding, or epoxy. If parts are secured by screws, then they might be disassembled to clear blockages. Some bonded constructions may have a low enough cost to be disposable. Then, mineral buildup or blockage is less of an issue since the water distributor  92   a-e  could be replaced along with the water panel  20 . 
     A sixth alternative embodiment of water distributor  92   f , shown in FIG. 11, has a manifold  70   f  provided with a group of six spaced apart, tortuous path, flow channels  76   f  which are in the form of a star-shaped wave surrounding a central core  156 . Each of the flow channels  76   f  is fed by inlet header  78   f  to a respective inlet port  80   f  and water flows to a respective outlet  84   f . This design works best in conjunction with upstream orifice  68 . 
     Unlike the Prior Art distribution tray  28 , there is no need to pumice-coat or endure uneven water distribution in the water distributor  92   a-f  which is of higher quality yet of lower cost than the known system. 
     While the invention has been described with reference to a preferred embodiment, those skilled in the art will appreciate that certain substitutions, alterations and omissions may be made without departing from the spirit thereof. Accordingly, the foregoing description is meant to be exemplary only, and should not be deemed limitative on the scope of the invention set forth with the following claims.