Abstract:
A housing is permanently connected to a water supply of a building and includes an evaporative water panel allowing water to flow downwardly and wick upwardly. A circulating device is provided for directing air from the building through the water panel. A reservoir is positioned in the housing for supporting the water panel and holding excess water deposited from the water panel. A water distributor is supplied for moving water from the water supply to a top of the water panel. A water control arrangement is responsive to the water level therein for automatically controlling the flow of water to the water panel to provide a desired humidity level in the building.

Description:
FIELD OF THE INVENTION 
     This invention relates generally to humidifiers, and more particularly, control of evaporation in a humidifier used in conjunction with a furnace or heating system and connected to the plumbing system of a building. Humidifiers of this type typically use an air circulation arrangement to move air across a water-soaked evaporative pad. The humidifier is associated with the furnace or heating system so that the humidifier moist air can be combined with the warm, generally dry, heated air and distributed through a building. 
     BACKGROUND OF THE INVENTION 
     Humidifiers generally characterized by a housing having an evaporative water panel constructed of slit and expanded non-wicking paper, removably disposed in a reservoir at the bottom thereof. The housing also has a mechanical float valve which is connected to a water supply of a heated building. A water feed tube is connected to the mechanical float valve for supplying water to a distributor from which water flows by gravity down through the water panel. Air is forced through the water panel and the air evaporates water on the water panel, so that humidified air is delivered to the building. 
     Such humidifiers typically employ a device such as a humidistat, for establishing predetermined humidity set point and reading humidity levels in the building. The humidistat is connected in a circuit with a pump and operates, in the presence of low humidity, to automatically deliver water from a lower reservoir to the top of the water panel and downwardly therethrough. Some of the water evaporates from the water panel and is air blown to provide humidity to the building. The remainder of the water collects in the reservoir at the bottom of the water panel. As the reservoir level drops due to loss of evaporated water, the float valve opens to allow water in from supply and maintains reservoir level. The pump recirculates water from the reservoir over the non-wicking water panel. This cycle continues as long as the humidistat reads low humidity. Once the humidity set point is reached, the circuit is opened and water flow ceases. 
     There also exist drum-type humidifiers wherein a motor and gear system is used to rotate a drum in a reservoir of standing water. 
     While such designs generally provide the desired humidification, there arises problems in the cost, noise, maintenance, electrical power needs and reliability associated therewith. Another problem with these designs is that the reservoir remains filled no matter if humidity is needed or not. As a result, there is a possibility of undesirable bacteria, algae, fungus, mold, etc. 
     Accordingly, it is desirable to provide a humidifier which is responsive to the changing water level in the reservoir. It is also desirable to provide a humidifier which is more economical in cost, runs more quietly, requires less maintenance and lessens the electrical power needs. 
     SUMMARY OF THE INVENTION 
     It is one object of the present invention to provide a humidifier employing a float switch which responds to the water level in the reservoir. 
     It is also an object of the present invention to provide a humidifier which employs a wicking-type evaporative water panel. 
     It is a further object of the present invention to provide a humidifier which allows for complete evaporation of water in the reservoir. 
     It is an additional object of the present invention to provide a humidifier which operates normally without the need for a drain. 
     Still another object of the present invention is to provide a humidifier which is easier to manufacture and maintain and which is safer to operate. 
     In one aspect of the invention, a housing is permanently connected to a water supply of a building and includes an evaporative water panel allowing water to flow downwardly and wick upwardly. A circulation device is provided for directing air from the building to the water panel. A reservoir is positioned in the housing for supporting the water panel and for holding excess water deposited from the water panel. A water distributor is provided for moving the water from the water supply to the top of the water panel. A water control arrangement is responsive to the water level within the reservoir for automatically controlling the flow of water to the water panel to provide a desired humidity level in the building. The water panel is comprised of a multi-layer, slit and expanded, wicking paper. In the preferred embodiment, the air circulating device includes a blower associated with a furnace, or a fan built integrally into the humidifier and the reservoir includes first and second vertical walls connected to a horizontal base wall. The water control arrangement includes a solenoid valve connected to a water level sensor. The water level sensor is preferably comprised of a float switch having a float member provided with a magnet therein, and a reed switch connected to the solenoid valve. The float member and magnet are positioned above the horizontal base wall of the reservoir, and the reed switch is aligned with the magnet and positioned below the reservoir, isolated from any water contact therewith. In the preferred embodiment, the reservoir includes a tubular chamber and the float member is a ball-shaped float. 
     The invention also contemplates various other methods for movably mounting the float member. In one embodiment the reservoir includes a post having one end of the hinge slidably attached thereto and another end of the hinge attached to the float member. In another alternative embodiment, the reservoir includes a post having one end of a solid folding hinge attached thereto and the other end of the solid folding hinge attached to the float member. In yet another alternative embodiment, the reservoir includes a set of posts upon which the float member is slidably mounted. In still another alternative embodiment, the reservoir includes a post provided with a pivoted edge having one end of a float arm pivotally attached. thereto and another end of the float arm attached to the float member. In still another alternative embodiment, the reservoir includes a horizontal ledge having one end of a flexible hinge attached thereto and another end of the flexible hinge attached to the float member. 
     The water distributor is a tube extending from the solenoid valve to an outlet nozzle and a weir-type distributor trough which is positioned over the water panel. The water distributor may also take the form of a feed tube extending from the solenoid valve to an outlet manifold positioned over the water panel. An overflow tube is molded directly to the side of the reservoir for receiving any water which overflows the reservoir. The humidifier typically includes a humidistat for establishing a desired humidity level. 
     In another aspect of the invention, the humidifier has a device for controlling the flow of water to an evaporative water panel positioned in a reservoir and allows water to flow downwardly and wick upwardly. The humidifier also has a humidistat for establishing a desired humidity level and an operative circulating means for directing air through the water panel. The humidifier includes a water level sensor which is associated with the reservoir and which is responsive to the water level therein to alternatively open and close a circuit to control the flow of water to the water panel. With this construction, when the water level in the reservoir is low, the circuit is closed to deliver water to the water panel such that some water evaporates from the water panel and the remainder collects in the reservoir. A rising water level in the reservoir causes the sensor to open the circuit, stopping water delivery, humidification continuing as water wicks upwardly through the water panel. The falling water level in the reservoir causes the sensor to close the circuit, delivering further water to the panel, the reservoir eventually drying out once the desired humidity is reached. The humidistat forces the circuit open when the desired humidity level is reached so as to prevent the water cycling on and off indefinitely. Stoppage of the circulating means will have the same effect. 
     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 DRAWINGS 
     The drawings illustrate the best mode presently contemplated of carrying out the invention. 
     In the drawings: 
     FIG. 1 is a side cross sectional view of a humidifier embodying the present invention; 
     FIG. 1A is a view of an alternative distributor in the form of an outlet manifold; 
     FIG. 2 is a fragmentary view of a reservoir and float switch arrangement of the humidifier of FIG. 1 with a low water level as taken on line  2 — 2  of FIG. 1; 
     FIG. 3 is a cross sectional view showing an overflow tube molded directly to the reservoir; 
     FIG. 4 is a diagrammatic view showing a typical start-up mode for the humidifier of FIG. 1; 
     FIGS. 5 and 6 are diagrammatic views depicting a humidification cycle for the humidifier of FIG. 1; 
     FIGS. 7 and 8 are diagrammatic views depicting a dry-down mode for the humidifier of FIG. 1; and 
     FIGS. 9-13 are alternative embodiments of various arrangements for movably mounting a portion of the float switch. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As seen in FIG. 1, a humidifier  10  embodying the present invention includes a base portion  12  and cover  14  which define a housing that is mounted on a portion of the furnace or on a wall or ceiling. Base portion  12  includes an evaporative water panel  16  preferably formed of a slit and expanded construction of wicking paper mounted in a framework or scale control  18 . Base portion  12  also includes a water feed tube  20  having one end which supplies water to a nozzle  22  and distributor  24  for the water panel  16 . Another end of feed tube  20  is joined to a solenoid valve  26  which controls the flow of water through the feed tube  20 . Solenoid valve  26  is, in turn, permanently connected to the plumbing or water supply  28  of a building. As depicted in FIG. 1A, distributor  24  may also take the form of a manifold  25  for conducting water therethrough. The humidifier  10  also includes air circulation means such as a furnace blower fan  30  (FIG. 4) for directing air through the wetted water panel  16 . A humidistat  31  (FIG. 4) is commonly used to set a desired humidity set point. 
     In accordance with the invention, part of the scale control  18  is provided with either an integral or separate small reservoir  32  for holding excess water supplied to the water panel  16 . As seen best in the preferred embodiment of FIGS. 2, reservoir  32  includes a tubular chamber  34  having a main well formed by a base wall  36  and first and second vertical walls  38 , 40 . A water level sensing float member  46  takes the form of a ball float  47  having a magnet  48  mounted internally within and supported on base wall  36  when the water level is low. Depending on the water level in the reservoir well, the ball  47  will be enabled to move up or down in chamber  34 . Referring to FIG. 3, molded to the side of the reservoir  32  is an overflow tube  54  for receiving any water which overflows the reservoir  32 . Reference numeral  51  indicates the normal water level in the reservoir  32 . If solenoid valve  26  fails and the water level goes too high, water drains over the lip  53  of overflow tube  54  and into a drain before it floods over the top of reservoir  32 . Attached to the base portion  12  beneath base wall  36  and between vertical walls  38 , 40  is a reed switch  62  which is suitably electrically connected to the solenoid valve  26 . As seen in FIG. 2, the reed switch  62  is aligned beneath the magnet  48  in ball float  47 . As will be understood more fully hereafter, the magnet  48  in the ball float member  47  cooperates with the reed switch  62  to define a float switch  70 . With water in the reservoir well at the low level, the float switch  70  has a closed position which will allow the solenoid valve  26  to remain open. With water in the reservoir well at a high level, the float switch  70  has an open position which will close the solenoid valve  26 . 
     Referring now to FIGS. 4-8, the operation of the humidifier  10  will now be described. It can be seen that a transformer  72 , a furnace sensor  74 , solenoid valve  26 , humidistat  31 , and float switch  70  are serially connected in a circuit and are responsive to the on/off condition of the motor-driven furnace fan  30 . When furnace fan  30  is “on”, sensor  74  closes, humidistat  31  senses low humidity when the water level in the reservoir  32  is low, and magnet  48  in float member  46  holds reed switch  62  closed, so that the float switch  70  is closed (FIG.  4 ). A circuit is completed to the solenoid valve  26  which opens and supplies water to the distributor  24  at the top of the humidifier  10 . Water drains from the distributor  24  and runs downwardly through the water panel  16 . Some water evaporates from the water panel  16  to provide humidity to the building. The remainder of the water collects in the reservoir  32  at the bottom of water panel  16 . As the water level rises (FIG.  5 ), the float member  46  lifts the magnet  48  away from the reed switch  62  to a point where the reed switch opens a circuit and causes the solenoid valve  26  to close. Humidification continues as water now wicks upwardly (FIG. 5) from reservoir  32  into the water panel  16 . This action is made possible by purposely constructing the water panel  16  with the slit and expanded wicking paper. Eventually, the water level drops (FIG. 6) and the magnet  48  again closes the circuit to solenoid valve  26 , so that more water enters the humidifier  10 . This cycle continues (FIG. 7) as long as the furnace fan  30  runs and the humidistat  31  reads low humidity. When the humidity set point has been satisfied, the reservoir  32  will dry out (FIG. 8) because water continues to wick into the water panel  16  and evaporates while the humidistat  31  holds the circuit open and prevents more water from entering the humidifier. 
     It should be appreciated that the humidifier  10  of the present invention provides a magnetic level sensing device in which the float member  46  and magnet  48  are placed in a separate assembly from reed switch  62 . This feature allows for easy replacement of the water panel  16  without having to disconnect any wires. It also maintains the electrical switch outside the water containing reservoir  32  which is safer and easier to manufacture because waterproofing is not needed. By downsizing the reservoir  32  and eliminating the pump of prior humidifiers. there is a reduction in cost, noise, and electrical power needs. Because the present invention is designed to dry out the reservoir  32 , undesirable biological growths are limited. Whereas the prior art relied on non-wicking paper for allowing downward migration of moisture, the present invention by virtue of the wicking paper also enables upward migration of moisture which aids the evaporation. 
     It should also be noted that while in the preferred embodiment the water level sensor has float member  46  in the form of a ball with a magnet  48  which floats in a tubular channel of the reservoir  32 , there are other arrangements contemplated to perform the same result. In the alternative embodiment in FIGS. 9, a flexible hinge  49  has one end connected to a float member  46  and another end having a mechanical pivot point, such as that of a stepped vertical shaft  76  in a hole formed in the flexible hinge  49 . In FIG. 10, a solid articulating or folding hinge  78  has one end connected to the float member  46  and another end connected to a vertical post  80 . In FIG. 11, float member  46  is mounted for sliding up and down movement on a pair of vertical posts  82 , 84 . In FIG. 12, a rocker arm  86  has one end connected to float member  46  and another end pivotably mounted on a pointed edge of a vertical post  90 . 
     In FIG. 13, a forward portion of the reservoir  32  includes a stepped compartment  92  having a main well formed by a base wall  94  and first and second vertical walls  96 , 98 . The shorter vertical wall  98  is formed with an outwardly projecting horizontal ledge  100  which turns into a third vertical wall  102 . A water level sensing float member  104  having a magnet  106  mounted internally within is supported on the base wall  94  when thew water level is low. A flexible hinge  108  has one end  110  secured to the top of float member  104  and has another end  112  anchored to the ledge  100 . A bottom wall  114  has a raised boss  116  creating an interior space for a reed switch  118 . Bottom wall  114  is also formed with a set of upright ribs  120 , 122  which function to locate vertical walls  96 , 98  therebetween with the base wall  94  of stepped compartment  92  resting upon an upper horizontal wall  124  of the boss  116 . The ribs  120 , 122  provide alignment of the reservoir  32  and its float member  104 , and magnet  106  with the reed switch  118 . 
     It is also noted that other means may be used to sense water, such as with electrical conductivity sensors, or optical, sound wave or weight sensing arrangements. 
     It should be mentioned that the reservoir  32  can be provided, if desired, with a downwardly depending conduit used to lead water away to a drain. This is a desirable safety feature which is useful should the solenoid valve  26  become jammed open or otherwise held open due to an electrical failure. However, in the intended operation, all water supplies would be evaporated and the drain would not be used. 
     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. For example, in humidifiers having an internal fan, the furnace sensor  74  would not be used, and the fan would be controlled via a relay added to the circuit.