Patent Publication Number: US-2009230572-A1

Title: Drum humidifier with pivoting floor

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a drum humidifier for adding moisture to unhumidified air. More specifically, it relates to an improved drum humidifier that allows the water pan to be removed while it maintains a horizontal position, reducing the opportunity of spilling the water. 
     Use of forced air systems for home heating is well known. A network of ducts is used to carry warm air throughout the home and return cool air to the furnace for reheating. Since cool air holds less moisture than warm air, household air that comes in contact with cool surfaces, such as windows, tends to condense a bit of the moisture, leaving the air dry. Dry air allows static electricity to build up, causing the familiar spark when people or pets touch conductive surfaces. If the dryness continues, moisture is drawn into the air from the skin and mucous membranes of the inhabitants or from wood products. 
     Adding moisture from a humidifier is a well known method of preventing dry skin, cracking and drying of furniture as well as making the environment more comfortable. Many types of humidifiers are known, including drum humidifiers. A drum humidifier has a hollow drum made of an evaporative element held on a substantially cylindrical frame. Rotation of the drum allows a portion of the evaporative element to come into contact with water that is absorbed. Unhumidified air from the furnace flows through the evaporative element, picking up moisture before the humidified air is returned to the furnace. 
     In a typical drum humidifier, water for absorption by the evaporative element is held in a water pan that rests on the base of the humidifier housing. A float on the surface of the water provides information as to when the water pan needs to be refilled. Traditionally, the float is positioned between the door of the housing and the drum. Since the float is necessarily on the water surface, it is lower than the height of the water pan walls. Thus, when the cover is opened and the water pan needs to be removed, the front edge of the pan has to be tipped downward to allow it to pass underneath the sensor. In this condition, the water is easily spilled. 
     Some prior art allows for movement of the float against a bias so for removal of the water pan and/or drum. The bias or spring encourages the float to return to its ready position without effort on the part of the user. However, in this type of humidifier, the user must hold the float out of the way with one hand while removing the pan with the other hand. In this situation, it is easy to tip the water pan, again resulting in spillage. 
     Thus, there is a need in the art for a way of removing the water pan of a drum humidifier without spilling the water, even when working in tight or awkward places. 
     SUMMARY OF THE INVENTION 
     These and other needs are met or exceeded by the drum humidifier of the present invention. More specifically, the drum humidifier simplifies the process of removing the water pan from the humidifier housing by allowing a portion of the floor to pivot downwards so that the water pan can be removed from the housing around the float assembly with a low likelihood of spilling the water. 
     The drum humidifier is designed for use with a forced air furnace and includes a housing including a base, a first side wall, a second side wall and a top. A removable water pan is positioned to be supported by the base. Water is maintained in the water pan by a watering means, the watering means comprising a float. A movable water pan floor, the water pan floor having an operating position and a maintenance position. The water pan floor is substantially coplanar with the base and is positioned under at least a portion of the water pan in the operating position. The water pan floor is moved to a maintenance position to allow removal of the water pan around a float while the water pan remains in a substantially horizontal position. 
     A drum is included within the humidifier having an evaporative element, and is positioned to draw water from the water pan. The drum is turned using a rotating means. 
     The pivoting floor of the present drum humidifier simplifies removal of the water pan from the housing without water spillage. Instead of requiring that the water pan be siphoned, pulled forward and tipped to remove it, it can be pulled forward and lowered vertically without having to drain the water. This allows movement of the sides of the water pan around the float assembly without the need to tip the water pan from a substantially horizontal plane. 
    
    
     
       DETAILED DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a left perspective view of the drum humidifier of the present invention; showing the cover removed for clarity; 
         FIG. 2  is a left perspective, exploded view of the drum humidifier of  FIG. 1 ; 
         FIG. 3  is an elevated, perspective view of the drum of the drum humidifier of  FIG. 1 ; 
         FIG. 4  is a right perspective, exploded view of the drum humidifier of  FIG. 1 ; 
         FIG. 5  is an elevated perspective view of the float assembly of the drum humidifier of  FIG. 1 ; and 
         FIG. 6  is an exploded, perspective view of the float assembly of the drum humidifier. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 1 , a drum humidifier, generally  10 , is shown for use with a forced air furnace (not shown). Unless otherwise noted, parts of the drum humidifier  10  are made of materials that hold their shape, withstand temperatures within the air ducts of a furnace, and will not mold or rust in the presence of warm, moist air. Preferred embodiments of the drum humidifier are made of thermoplastics or of rust-free metals, such as aluminum. All references to the relative positions of various features are to be interpreted as if the humidifier  10  is oriented as shown in  FIG. 1 . 
     The drum humidifier  10  includes a housing, generally  12 , that serves to contain its features, direct air flow and to provide an aesthetically pleasing appearance to the exterior of the humidifier. Components of the house  12  include a base  14 , a first side wall  20 , a second side wall  22 , an optional back wall  24  and a top  26 . The first and second side walls  20 ,  22  are positioned between the base  14  and the top  26  of the housing  12  opposing each other. 
     A cover  30  is configured and adapted to cover the front of the humidifier housing  12 . This allows access to the humidifier  10  when maintenance is needed. The cover  30  is openable to the top or either side. It is also contemplated that the cover be reconfigurable by the user, since the availability of space between one furnace and another is variable. Where a cover  30  opening to one side may provide the easiest access in some embodiments, in other embodiments it may be more advantageous to have a door that swings upward or to the other side. The cover  30  optionally includes a window or lens  32  to view inside the humidifier  10 . 
     As shown in  FIG. 2 , the door  30  has a curved shape, however it is contemplated that the door  30  be of any shape as long as it fits the shape of the housing  12  and it helps to direct air flow from an air inlet  34  to an air outlet  36 . The air outlet  36  is an opening cut into the back  24  of the housing  12 . Unhumidified air flows from the air inlet  34  into the housing  12 . Once inside the housing  12 , the air passes through an evaporative element  40  and becomes humidified air. Humidified air is directed toward the air outlet  36 . 
     Although this description assumes that air enters the unit through side wall  22  and exits through the back  24  of the housing, it is to be understood that it is equally suitable for air to enter through the back  24  of the humidifier  10 , and exit through the side wall  22 . Air will flow from areas of high pressure to areas of low pressure. If the back  24  of the humidifier  10  is attached to a high pressure duct of the furnace, such as the hot air duct exiting the furnace, and the air exiting the humidifier  10  is fed to a lower pressure duct, such as a cold air return, than the air will flow in from the back  24  and out the side wall  22 . If the back  22  is attached to a low pressure duct and the side wall gets air from a higher pressure duct, then the air will flow as described below. The humidifier  10  can be installed either way, giving the installer some flexibility in where to place the unit. 
     A collar  42  is inserted into the second side  22  of the housing  12 . The collar  42  includes a plurality of blades  44  that position a center  46  support for receiving a first axle  50 . This support keeps a drum shaft  52  approximately coaxial with a drum, generally  54 . The collar  42  also serves effectively as the air inlet  34  for the humidifier  10 , with dry air entering the humidifier  12  between the blades  44  of the collar  42 . Any number of blades  44  can be used. Additional blades  44  provide progressively less additional support and reduce the amount of incoming air since there are additional friction surfaces over which the incoming air must pass. Where needed, an extension duct (not shown) can be attached to the collar  42  to carry air from a furnace duct to the humidifier  10  to the air inlet  34 . 
     Referring to  FIGS. 2 and 3 , the air inlet  34  is positioned in the second side wall  22  of the housing  12 . In this embodiment, the drum  54  is positioned between the first side wall  20  and a second side wall  22 . The funnel-shaped drum shaft  52  has a wide end  60  and a narrow end  62 , where the narrow end is closest to the second side wall  22 . The first axle  50  and a second axle  64  protrudes from the shaft  52  at each end  60 ,  62 , each axle  50 ,  64  substantially being coaxial with the shaft  52  itself. The first axle  50  at the narrow end  62  of the shaft  52  while the second axle  64  is positioned at the wide end  60  of the shaft  52 . The drum  54  is open to the flow of unhumidified air at the narrow end  62  and closed to the flow of unhumidified air at the wide end  60  of the drum shaft  52 . 
     A drum body  66  is substantially coaxial with the shaft  52 , supporting it and holding it in place. The drum body  66  includes two coaxial rims, a first rim  70  and a second rim  72 , that are connected to each other with a plurality of ribs  74 . Each of the ribs  74  is approximately the same length, from the first rim  70  to the second rim  72 . From the end of the drum body  66  closest to the second side wall  22  and moving inwardly along a radius, the drum shaft  52  tapers from the axle  50  to the second rim  72 , in a continuous frusto-conical shape. From the second axle  64  and continuing to move inwardly along a radius, a second cone-shaped section  75  is formed. This second cone-shaped section  75  tapers from its intersection with the drum shaft to the second axle  64 . The second axle  64  engages with the motor  80  to turn the drum, keeping it moist with water. 
     The drum  54  supports one or more of the evaporative elements  40 . More specifically, the plurality of ribs  74  is used to support the evaporative element  40 . The exact number of ribs  74  varies with the diameter of the drum  54  and the weight of the evaporative element  40 , particularly when wet. One preferred embodiment includes about six ribs  74 , however, the number of ribs  74  can vary depending on the exact evaporative material used and its weight when wet. Preferred embodiments of the drum  54  include an even number of ribs  74 . This allows the sheet of evaporative material  40  to be woven over and under the ribs  74  with both ends of the sheet meeting on the same side of the ribs  74 . 
     The evaporative element  40  can be made of any material that can absorb water when dipped into a water pan  76 . Preferred embodiments of the evaporative element  40  use a thin foam or cellular material that absorbs water as it passes through the water pan  76 . An example of a preferred cellular material  60  is reticulated ether-based polyurethane foam. Any type of evaporative material  40  as is known in the art can be used in this humidifier  10 . If paper is used, a greater number of ribs  74  may be needed to control sag of the evaporative element  40 . Sturdier evaporative materials, such as slit and expanded metals, may require fewer ribs  74 . 
     As discussed above, the drum shaft  52  has a conical shape. The diameter of the drum shaft  52  expands when moving axially along the drum shaft from the first axle  50  to the drum body  66 . Most of the air flowing into the drum  54  initially moves approximately parallel to the drum axis. As the air comes in contact with the drum shaft  52 , it is deflected outward by the funnel shape toward the evaporative element  40 . The gradual increase in diameter distributes the deflected air along the length of the evaporative element  40  so that a large portion of the evaporative element  40  surface has dry air moving through it. In this manner, a substantial portion of the evaporative element  40  is effectively utilized to distribute water. 
     The drum  54  is supported between the rotating means  80  in the first side wall  20  and the collar  42  in the second side wall  22 . The second axle  64  is inserted into the center support  46  in collar  42  in the second side wall  22 . A rotating means  80  is mounted through a mounting plate  82  attached to the interior of the first side wall  20 . In a preferred embodiment, the rotating means  80  is an electric motor designed to slowly turn the drum  54 . As the dry air passes through the evaporative element  40 , moisture is depleted from the evaporative element  40  as it is entrained in the air. The radius of the drum  54  is designed to be greater than an altitude from the surface of water in a water pan  76  to the drum axis. This ensures that the evaporative element  40  is wetted by the water, continuously rotating the evaporative element  40  to wet substantially the entire surface. Optimally, the rotating means  80  rotates the drum  54  at a speed whereby the drying time of the evaporative element  40  is substantially the same as the time of one revolution of the drum  54 . A motor cover  84  mounted to the exterior of the first side wall  20  covers the rotating means  80 . 
     The base  14  of the housing acts to support the removable water pan  76  positioned thereon. The water pan  76  is sized and configured to hold water that is picked up by the evaporative element  40 . The drum humidifier  10  could be designed to accommodate any size or shape of water pan  76 . Practically, the water pan  76  accommodates the entire width of the drum  54  in order to wet the evaporative element  40 . The humidifier  10  is mounted to the ductwork of the furnace. The ductwork is not designed to hold a great weight mounted thereto. It is generally not practical to make the capacity of the water pan  76  in excess of one gallon due to the weight of the water that would result if the pan were filled to capacity. In a preferred embodiment, the capacity of the water pan  76  is approximately one-half gallon. 
     In a preferred embodiment, it is preferable to refill the water pan  76  at frequent intervals rather than have a large, heavy water pan  76 . Another element of the humidifier  10  is a filling means for maintaining water in said water pan. A float assembly, generally  86 , is designed for this purpose. Referring to  FIGS. 5 and 6 , the float assembly  86  having an orifice  90  is mounted through the second side wall  22 . In one embodiment it is mounted using a mounting nut  92  and optionally cushioned with a flexible pad  94 . The portion of the orifice  90  extending through the second side wall  22  is a water supply  96  to furnish water with which to refill the water pan  76 . A discharge  98  is shaped into the bottom of the orifice  90  through which the water enters the humidifier  10  and the water pan  76 . 
     The orifice  90  is configured to hold a pair of legs  100  on a water feed plate  102 . At least one pivot pin  104  passes through the orifice  90  such that the legs  100  pivot within the orifice  90 . It is contemplated that the pivot pin  104  can be a single pin that passes through both the orifice  90  and the legs  100 , or it can be a pin integral to each of the pair of legs  100  that extends through a pair of openings  106  in the orifice  90 . Any pivot mechanism  104  can be used that allows movement of the water feed plate  102  with respect to the orifice  90 . The legs  100  are further configured to allow the pivoting motion of the water feed plate  102 . Whatever pivot mechanism  104  is used, it should be sufficiently flexible so as to allow a float  110  determine the position of the water feed plate  102 , but not have the water feed plate  102  holding the float  110  above or below the surface of the water. 
     Between the legs  100  and facing the orifice  90 , the water feed plate  102  has a stopper  112  that acts as a valve to stop the flow of water when the water feed plate  102  is in an upright position. In this position, the top of the legs  100  are in contact with the orifice  90 . The stopper  112  is positioned to fit into the water supply  96  to block flow of water into the water pan  76  when it is sufficiently full to wet the evaporative element  40 . However, as the water feed plate  102  pivots, the tops of the legs  100  loose contact with the orifice  90  and the stopper  112  is pulled away from the water supply  96 . Sufficient movement of the water feed plate  102  frees the stopper  112  from the water supply  96 , allowing flow of water through the discharge  98  to the water pan  76 . 
     Included on the water feed plate  102  is a tab  114  that extends normally to the plate opposing the legs  100 . The tab  114  has a slot  116  that is used to attach a float arm  120  to the water feed plate  102 . A thumbscrew  122  fits through the slot  116 , then into a first aperture  124  in the float arm  120 . A nut  126  secures the thumbscrew  122 , preventing slippage between the water feed plate  102  and the float arm  120 . At an end  128  of the float arm  120  opposite the water feed plate  102  is a float  110 . It is contemplated that the float  110  be attached to the float arm  120  by any known means. One preferred method is by use of a cotter pin  132  through at least one second aperture  134  in the float arm  120  and through an orifice  130  in the float  110 . Preferably the cotter pin  132  is secured through a pair of second apertures  134  with the orifice  130  sandwiched between the second apertures  134 . 
     The float  110  floats on the surface of the water in the water pan  76 , ranging from an upper position to a lower position. In the upper position, the water in the water pan  76  is sufficiently deep to easily wet the evaporative element  40  as it is rotated through the pan. When in the upper position, the stopper  112  is fully engaged in the water supply  96  so that no water enters the drum humidifier  10 . If the float  110  is in the lower position, the water in the water pan  76  has become depleted and it is desirable to add water thereto. As the float  110  moves from the upper position to the lower position, the float  110  draws the float arm  120  downward with it. Downward movement of the float arm  120  causes the water feed plate  102  to pivot, slowly pulling the stopper  112  from the water supply  96 . Further movement of the float  110  to the lower position eventually pulls the stopper  112  from the water supply  96 , allowing flow of water to the water pan  76 . Addition of water then causes the float  130  to begin to rise, pushing the float  110  and float arm  120  upwards. As the water feed plate  120  pivots in the opposite direction, the stopper  112  is slowly pushed into the water supply  96 , decreasing the flow of water. At the upper position, the stopper  112  is fully engaged in the water supply  96  so that no water flows into the water pan  76 . 
     Referring to  FIGS. 1 ,  2  and  4 , a water pan floor  136  allows the water pan  76  to be removed from the housing  12  with reduced chance of spilling it. The water pan floor  136  moves from being in an operating position to a maintenance position. While humidified air is being introduced to the furnace, the water pan floor  136  is in the operating position. In this position, the water pan floor  136  is substantially coplanar with the base  14 . It is also positioned to be under at least a portion of the water pan  76 . When humidity is called for, the evaporative element  40  rotates on the drum  54  so that a portion of the evaporative element  40  is in contact with the water. The evaporative element  40  picks up water from the water pan  76 , depleting the amount of water therein. 
     However, when the evaporative element  40  needs to be changed, or other maintenance needs to be done, it is necessary to remove the water pan  76 . At this time, the water pan floor  136  is moved to the maintenance position. In the maintenance position, the water pan floor  136  is no longer substantially coplanar with the housing base  74 . The water pan floor  136  moves to a position that allows removal of the water pan  76  around the float  110  while said water pan  76  remains in a substantially horizontal position. 
     The water pan floor  136  can be moved to a variety of positions. Preferably, the water pan floor  136  is pivotally attached to the housing base  14 . This arrangement allows it to pivot on so that an edge  138  opposing a pivot  140  swings downward, away from the plane of the housing base  14 . To allow the water pan  76  to pass through the resulting opening in a substantially horizontal position, the opposing edge  138  should rotate at least 90° from the housing base plane. In some embodiments, the opposing edge  138  of the water pan floor  136  rotates from about 90° up to 180° from its position substantially parallel to the housing base plane. The water pan floor  136  is “substantially coplanar” with the housing base if, while resting on the surface created by the base  14  and the water pan floor  136  in the operating position, there is no spillage of water when the water pan  76  fills with water to the level of the float  110  in the upper position. Optionally, the water pan floor includes one or more drain holes  141 , each of which includes a drain spout  143 . 
     Change in position from the operating position to the maintenance position is initiated by release of the water pan floor  136  from the operating position. The water pan floor  136  is held in the operating position by a latch  142 . One of the group consisting of the cover  30 , the housing  12  or both secures the water pan  76  floor during operation. When maintenance begins that requires removal of the water pan  76 , the latch  142  is released. In some embodiments, the water pan floor  136  is releasably attached by the latch  142  to the housing cover  30 . In these embodiments, release of the latch  142  also releases the housing cover  30  allowing it to open substantially simultaneously with the movement of the water pan floor  136 . 
     It is also contemplated that in some embodiments, the water pan floor  136  will optionally be held in place in the maintenance position by the latch  142  that removably attaches it to the housing base  114 , first side wall  20  or second side wall  22 . This feature holds the water pan floor  136  out of the path to be traveled by the water pan  76  while removing it for maintenance. Suitable latches  142  include magnetic latches, push latches and friction latches. 
     While a particular embodiment of the catalyst for the set acceleration of spray applied plaster 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.