Abstract:
A humidification system includes a humidifier housing mountable to the air duct. The humidifier housing has an opening to provide fluid communications between the humidifier housing and the air circulation system. An air inlet extends through the duct opening into the humidifier housing. A duct damper extends into the air duct and is reversibly positionable between a stowed position and a deployed position. The stowed position is characterized by placement of the duct damper substantially adjacent to the humidifier housing while the deployed position is characterized by positioning a portion of the duct damper deeper into the air duct. An evaporative element is positioned between the air inlet and an air outlet. A cover is configured to reverse the direction of flow air sending it to the air outlet extending into the air duct. A deploying means changes the duct damper between the stowed position and the deployed position.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to humidifiers, particularly humidifiers for hot air furnaces and heating systems. More specifically, the instant humidifier allows the volume of air flowing through the humidifier to be adjusted. 
       BACKGROUND OF THE INVENTION 
       [0002]    Humidifiers for hot air furnaces and space heating systems are typically comprised of a housing having an air inlet and an humidification system for passing space heating air from the furnace through the housing and over and/or through a water fed evaporator in the housing for moistening the heating air passing through the housing and to the space heating system. The structure, mode of operation and beneficial effects of hot air furnace humidifiers are well known. 
         [0003]    A typical bypass humidifier to be used in association with a hot air furnace includes warm or hot air supply ducting, cool or cold air return ducting and an internal blower for forcing heated air from the furnace through the ducting. The humidified air is forced to a space to be heated. Cool air from the space is pulled or drawn through the ducting back to the furnace to be reheated and re-circulated through the space. A bypass humidifier has an inlet in its back wall connected in fluid communication with one or the other of the ducts, usually the hot air supply ducting, and an outlet connected in fluid (gaseous) communication with the other of the ducts, usually the cool air return ducting. Due to the differential between the relatively higher pressure airflow in the supply ducting and the relatively lower pressure airflow in the ducting, air is induced to flow from the supply ducting through the humidifier to the return ducting, thereby causing air to flow over and/or through an evaporator unit in the housing to moisturize, i.e., humidify, the air flowing through the space heating system. A damper installed at the outlet of the humidifier controls the amount of air passing through the humidifier and thus the amount of moisturized air delivered to the space to be heated. 
         [0004]    U.S. Pat. No. 5,368,784 suggests a method of improving air flow through the humidification system by placing a scoop inside the air duct so that pressure from the flowing air can be harnessed to push dry air through the humidifier. Air is forced into the humidification system, through an evaporative element, then turned 180° to exit back through the evaporative element and exits via an outlet back into the air duct. This improvement provides continuous humidification and requires only a single opening in the air duct for installation. 
         [0005]    A disadvantage of this humidifier is that there is no way to change the amount of air that enters the humidifier for use with a variety of furnaces, ducts and conditions. During extreme cold, the air is very dry. The thermostat may call for the furnace to turn off before the air is humidified to the desired extent. In such a case, it would be desirable to be able to divert more air through the humidifier to reduce dryness. 
         [0006]    Other fixed duct scoops are known having multiple louvers that extend into the air duct. However, any fixed scoop has the disadvantage of always diverting the same amount of air into the humidifier, regardless of how much air is needed to provide the appropriate quantity of humidified air. Constant diversion of the air through the evaporative element utilizes energy by the fan to force the air through the humidifier even when it is not needed. When it is especially dry, no additional air can be sent to the evaporative element to provide higher average moisture content. Thus, energy could be reduced or the range of humidification could be extended by utilizing a mechanism that varies the amount of air that is diverted through the humidifier. 
       SUMMARY OF THE INVENTION 
       [0007]    An air humidification system is designed for use with a forced air circulation system having an air duct with air circulating therein. The humidification system includes a humidifier housing mountable to the air duct. The humidifier housing has an opening adapted to be aligned with a duct opening to provide fluid communications between the humidifier housing and the air circulation system. An air inlet extends into the air duct for directing unhumidified air from the air duct through the duct opening into the humidifier housing. A duct damper also extends into the air duct and is reversibly positionable between a stowed position and a deployed position. The stowed position is characterized by placement of the duct damper substantially adjacent to the humidifier housing while the deployed position is characterized by positioning a portion of the duct damper deeper into the air duct to increase in air flow into the air inlet compared to when the duct damper is in the stowed position. An evaporative element is positioned between the air inlet and an air outlet and configured to provide water in the path of the unhumidified air to convert it to humidified air. A cover is configured to reverse the direction of flow of the humidified air sending it to the air outlet extending into the air duct for directing flow from the humidifier housing into the air duct. A deploying means changes the duct damper between the stowed position and the deployed position. 
         [0008]    The humidification system of the present invention allows the amount of air that flows through the evaporative element to vary depending on the season of the year. Reduction in size of the humidifier allows the air within the heating system to flow more freely and heat the air more effectively. Use of the duct damper forces large amounts of air through the humidifier only when it is necessary and can result in energy savings. 
     
    
     
       DETAILED DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a an elevated perspective drawing of the humidification system of the present invention installed for use on a forced air furnace; 
           [0010]      FIG. 2  is an elevated perspective view of the air handling system of the present invention with the damper in the stowed position; and 
           [0011]      FIG. 3  is a side cutaway view of the air duct of  FIG. 1 , showing the humidification system in the duct with the damper in the deployed position. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0012]    Referring to  FIG. 1 , a humidification system, generally  10 , is shown installed into an air duct  12  of a heating system, generally  14 , of a building (not shown). The heating system  14  includes a fan (not shown) and a furnace  22  for heating circulating air. Although this humidification system  10  could be used with an air conditioning system, it is generally not needed because warm outdoor air that is available during the cooling season holds more moisture than cold outdoor air available during the heating season. 
         [0013]    It is envisioned that the present humidification system  10  could be used with any heating system  14  that benefits from humidification of air  24  flowing through it, and wherein a pressure differential exists in the air duct  12  that is usable to divert unhumidified air  32  through the humidification system  10 . The pressure differential must be sufficient to push a reasonable amount of unhumidified air  32  through the humidification system  10  for the intended purpose. A duct damper  20  is used to modify the amount of unhumidified air  32  that is diverted through the humidification system  10 . The description that follows an exemplary humidification system  10  is described as being used with a forced air furnace  22 , but is not intended to be limited to that application. Further, directional references made in the discussion that follows are to be interpreted as if the humidification system  10  is oriented as shown in  FIG. 2 . 
         [0014]    The humidification system  10  includes an air handling system, generally  18 , a humidifier housing, generally  34 , an evaporative element  36 , a pad frame  38 , and a means of controlling humidity output  40 . The air handling system  18  includes an air inlet  28 , an air outlet  30  having a plurality of louvers  44  and the duct damper  20  ( FIG. 2 ). With the exception of the evaporative element  36  described below, any material can be used to manufacture these parts as long as it does not rust and is strong enough to hold its shape under the pressure and flow of the air in the forced air system. Typical materials include metals, such as aluminum, plastics including thermoplastics or plastic coated materials. Materials that are good choices for this application will not absorb or retain water that can breed molds or bacteria. At least one embodiment of this invention uses thermoplastic materials for the manufacture of the humidification system  10 . 
         [0015]    Referring to  FIG. 1 , the humidification system  10  is mountable to a surface of the air duct  12 . In the example discussed below, the housing  34  is attachable to the air duct  12  where there is sufficient pressure to push air through the humidification system  10 . In a forced air furnace  22 , the pressure is highest just downstream of the furnace fan. Other placement arrangements that will be obvious to an artisan are contemplated for use with this invention. 
         [0016]    In at least one embodiment, the humidification system  10  is mountable to the furnace  22  air duct or plenum  12 . In order to mount the humidification system  10  it is necessary to cut a duct opening  26  in the air duct  12 . A base frame  60  is the portion of the housing that attaches the humidification system  10  to the air duct  12  and defines the duct opening  26 . The duct opening  26  should be cut into the duct approximately the same size and shape as the base frame  60  to minimize leakage of air where the air duct and the base frame meet. The base frame  60  is then mounted to the air duct  12  and secured thereto with fasteners (not shown), such as sheet metal screws. A square or round duct opening  26  is used in at least some embodiments to facilitate use of the humidification system  10  with either horizontal or vertical flow furnaces. 
         [0017]    Parts of the housing  34  include the base frame  60 , a cover  70  and at least one side panel  72 . The base frame  60  mounts to the duct opening  26  in the air duct  12  as discussed above. The cover  70  is attachable to the base frame  60  by any means of removably attaching it. Examples of means of removably attaching the cover is by use of removable fasteners, a ridge and groove (not shown) to attain a snap fit, friction fit or a hinge and latch. Various fastening methods can also be used together, such as using a snap fit to hold parts in place then using auxiliary fasteners for strength. 
         [0018]    The shape of the cover  70  should be such that, after flowing through the evaporative element  36 , the direction of the humidified air is reversed back through the evaporative element  36  to the air outlet  30 . Some embodiments of the cover  70  are configured with a semi-circular shape to minimize dead spots, directing the air around and out through the evaporative element  36 . Multiple angled flat panels  74  are optionally be used to approximate a semi-circular shape. The use of additional angled panels (not shown) to better direct the air flow toward the humidification system  10  are contemplated. As it is visible from the living space in the vicinity of the furnace, the cover  70  optionally includes design elements (not shown) that give it a pleasing appearance. 
         [0019]    At least one evaporative element  36  is positioned between the air inlet  28  and the air outlet  30 . The pad frame  38  supports the evaporative element  36  and holds it in place. The evaporative elements  36  are well known in the art, for example slit and expanded metal pads that provides an evaporative surface for air flowing through the element. Alternative evaporative elements may be used, including wicking types. For the purposes of this application, the term “evaporative element” includes all devices for evaporating water to provide humidification. As air is directed through the evaporative element  36 , water evaporates and becomes entrained in the air  24 , thereby humidifying it. If more than one evaporative element  36  is present, any additional evaporative elements are also positioned to receive unhumidified air  32 , not humidified air  58 . 
         [0020]    Preferably the air  24  is directed over the evaporative element  36  twice. As the warm air is contacted with the water, heat from the air  24  is used to vaporize the water. It is unlikely that the air will be saturated in a single pass through the evaporative element  36 . Reversing the flow of the air  24  in the cover  70  and allowing it to pass through the evaporative element  36  a second time increases the degree of saturation compared to single-pass airflow. 
         [0021]    The means for controlling humidity output  40  controls the delivery of water to the evaporative element  36 . For example, the moisture can be controlled via a solenoid operated water valve  40 , thereby to attain and maintain a predetermined degree of relative humidity in the air being conducted by the furnace fan through the space to be heated. The control circuitry (not shown) for the humidification system  10  preferably comprises a temperature sensor/transmitter unit (“thermostat”) and a humidity sensor/transmitter unit (“humidistat”) installed at an appropriate location or locations in the room or space heating and furnace system  22 . Optionally contained within the housing  34  is a wireless temperature receiving unit, a wireless humidity receiving unit, a transformer, a thermister and/or any suitable switches and electrical/electronic components (not shown) for operating the solenoid valve  40 . As used herein the term “means for controlling humidity output”  40  means any mechanical, electrical and/or electromechanical device or assembly for controlling humidity output of the humidifier, including but not limited to the aforesaid solenoid operated water valve  40  to selectively provide water to the evaporative element  36 . 
         [0022]    After passing through the evaporative element  36 , the air is directed to the air outlet  30 . The air outlet  30  extends into the air duct so that the humidified air is deposited into the stream of air flowing to the furnace. Use of the air outlet  30  also prevents humidified air from reentering the humidification system  10  where it is unlikely to pick up additional moisture. In some embodiments, the air outlet  30  includes a plurality of louvers  44 . 
         [0023]    The plurality of louvers  44  is attached to the bypass frame  22 , positioned at least partially within the air outlet  30 . As shown, the louvers  44  are an integral part of the air handling system  18 , however attachment of individual louvers  44  is contemplated. The number of louvers  44  to be used is variable, depending on the physical size of the humidifying system  10 , and the degree of humidification per pass that is desired. At least two louvers  44  are used, but the addition of more louvers  44  is contemplated. Use of the louvers  44  provides a smooth transition for the humidified air from the housing  34  to the air duct  12  with a minimum of turbulence. As the number of louvers  44  increases, the humidification increases. The number of louvers is preferably between two and ten, or even greater. 
         [0024]    Each of the louvers  44  directs a portion of the air from the evaporative element  36  to a section of the air duct  12 . In some embodiments of this invention, the depth of the louvers  44  increases progressively moving deeper into the air duct  12 . More specifically, the shallowest louvers  44  are encountered by the air flow closest to the bottom of the housing  34  and the deepest louvers are utilized by the air flowing close to the center of the evaporative element  36 . Although the increase in depth need not be uniform between one louver  44  and the next, it is one option in selecting the depth of the louvers. Another method of selecting the size of the louvers  44  is to choose a size which results in uniform amounts of air being directed into the various portions of the air return  46 . Size and configuration of the louvers  44  may vary as long as they divert some of the air in the housing  34  back into the heating duct  12 . 
         [0025]    The louvers  44  may be any shape that directs air out of the humidifying unit  10 . As shown in  FIG. 3 , louvers  44  preferably have a curved portion  88  are useful for smoothly redirecting the flow of humidified air. This is a simplified drawing as actual air currents will be more complex. Each louver scoops a portion of air  24  from the evaporative element  36 . Then the portion of air is channeled by the curved area  88  toward the air duct  12 . Each air portion is diverted to a different area of the air duct  12  and in the same direction as the duct airflow to minimize air turbulence. As shown in  FIG. 2 , the louvers  44  extend the entire width of the bypass frame  22 , however, a louver  44  may also be used that extends into the air duct  12  over only part of its width. 
         [0026]    As shown in  FIG. 1 , this humidification system  10  is oriented for use with a vertical flow furnace. Another embodiment of the invention has been modified for use with a horizontal flow furnace. The modifications include orienting the louvers  44  such that unhumidified air  32  is directed into the humidifier  10  and humidified air  58  is returned to the air duct  12 . Other modifications will be known by artisans for adapting this humidification system  10  to other furnace types. 
         [0027]    A method for humidification includes withdrawing a portion of unhumidified air  32  through an air inlet  28  from the air duct  12  using a scoop  42  and directing it to the evaporative element  36 . The unhumidified air  32  then flows through the evaporative element  36  whereby it is at least partially humidified. Moisture is maintained on the evaporative element  36  by any known means. Examples of ways of maintaining moisture on the evaporative element  36  include wicking of water by the evaporative element  36 , dripping or flow of water onto the evaporative element  36 , preferably from above the evaporative element  36 , spraying of water and dipping of at least a portion of the evaporative element  36  into water. 
         [0028]    The humidity in the building is preferably controlled using a controlling device  40  such as a humidistat and solenoid valve. As long as the controlling device calls for additional humidity, the solenoid valve  40  remains open and moisture is maintained on the evaporative element  36 . However, when the humidistat is satisfied, the solenoid valve  40  closes, stopping the flow of water. The evaporative element  36  is then allowed to become dry, no longer containing water to evaporate into the unhumidified air  32 . 
         [0029]    After passing through the evaporative element  36 , the humidified air is channeled out of the evaporative element  36 , the direction of the humidified air is reversed and it is returned for a second pass through the evaporative element  36 . The humidified air  58  is then returned to a portion of an air duct  12  via louvers  44  in air handler  20 . 
         [0030]    The duct damper  20  is attached to the humidification system housing  34  in a manner that allows it to be positioned in a stowed position and a deployed position. In some embodiments, the damper is rotatably attached to the humidification system housing. Optionally, the duct damper  20  is able to be positioned at one or more intermediate positions between the stowed position and the deployed position. When in the stowed position, a minimum amount of air is directed through the air inlet passageway. Varying the position of the duct damper  20  changes the volume of air guided into the humidifier relative to the volume of air moving within the duct past the humidifier. In many embodiments, movement of the duct damper  20  toward the deployed position effectively extends the penetration of the inlet passageway deeper into the air duct  12 . Optionally, the duct damper  20  rotates on one or more hinge  56 , however other methods of varying the position of the duct damper are contemplated. 
         [0031]    As shown in  FIG. 3 , one embodiment of the duct damper  20  includes a top  60  that is hingedly attached to the air handler  18  of the humidification system housing. When in the stowed position, a first side  62  is attached to the air handler top and extends toward the bottom of the louvers  44  where it is attached to a damper bottom  64 . Often the first side is rectangular, but any shape is optionally used that varies the air flow through the duct as desired. The damper bottom is approximately opposite the top. In this embodiment, the damper bottom is planer and fixed normal to the first side  62 . However, embodiments are contemplated whereby the bottom and first side form a single curved surface, much like the shape of the air inlet  28 . Other contemplated embodiments include planer bottoms fixed to the first side  62  at obtuse or even acute angles. It is also contemplated that second  66  and third sides  68  extend from the damper bottom  64  along either side of the first side  62  to the damper top  60 . The second  66  and third sides  68  reduce the amount of air  24  that flows easily around the duct damper  20  by trapping a portion of the air within the damper sides. 
         [0032]    The presence of the duct damper  20  occupies space that would be used for air flow were the duct damper not present in the air duct  12 . This increases the local air pressure, forcing more air into the air inlet  28  than if the duct damper  20  not present at all. In the stowed position, the duct damper  20  causes a minimum amount of air to be pushed through the air inlet  28 . Deployment of the duct damper  20  pushes the damper bottom deeper into the air duct  12 . As the damper extends into the duct  12 , it blocks the flow of more air than when it is in the stowed position. Air pressure around the duct damper again increases, resulting in still more air to be pushed into the air inlet  28 . When the duct damper  20  is fully deployed, a maximum amount of air  24  enters the air handler  18  for humidification. 
         [0033]    Preferably, a deploying means  76  is added to aid in deployment of the duct damper  20 . An exemplary deploying means  76  is a deployment arm that extends through the air handler  18  and attaches to the duct damper  20 . The deployment arm is movable between a first position, placing the duct damper  20  in the stowed position, and a second position, converting the duct damper  20  to the deployed position. It is contemplated that the deployment arm  76  also holds the duct damper  20  in one or more intermediate positions. Optionally, a stop or locking mechanism  78  holds the deployment rod in the first position, the second position and any intermediate positions. The stop means is optionally a slot through which the deploying means  76  protrudes which produces sufficient friction to hold the deploying means  76  in position. 
         [0034]    While a particular embodiment of the apparatus and method for humidifying air has been shown and described, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects and as set forth in the following claims.