Abstract:
A steam humidifier having a water tank with a quick assembly feature. The steam humidifier includes a removable tank, where the removable tank is configured to contain water to be heated to generate steam and a handle that is configured to selectively secure the removable tank to the humidifier. The handle defines at least a first rotational position in which a tank support feature on the tank is engaged with a handle support feature on the handle such that the tank is attached to the humidifier. The handle further defines at least a second rotational position in which the tank support feature is disengaged from the handle support feature such that the tank is unattached from the humidifier. Additional embodiments are disclosed.

Description:
FIELD OF THE INVENTION 
   The invention relates to steam humidifiers, and more particularly, to constructions for a tank of a steam humidifier. 
   BACKGROUND OF THE INVENTION 
   The interior spaces of buildings are often at a lower than desired level of humidity. This situation occurs commonly in arid climates and during the heating season in cold climates. There are also instances in which special requirements exist for the humidity of interior spaces, such as in an art gallery or where other delicate items are stored, where it is desired that the interior humidity levels be increased above naturally occurring levels. Therefore, humidifier systems are often installed in buildings to increase the humidity of an interior space. 
   Humidification systems may take the form of free-standing units located within individual rooms of a building. More preferably, humidification systems are used with building heating, ventilation, and air conditioning (HVAC) systems to increase the humidity of air within ducts that is being supplied to interior building spaces. In this way, humidity can be added to the air stream at a centralized location, as opposed to having multiple devices that increase humidity at multiple points within the building interior. Additionally, because the air within ducts may be warmer than the interior space air during a heating cycle, the additional air temperature can help prevent water vapor from condensing in the vicinity of the humidifier, such as on the inside of the duct. 
   An issue associated with humidification system is that they should only discharge water vapor into a duct and not liquid water. Liquid water within a duct can create a number of serious problems. For example, liquid water that remains stagnant within a duct can promote the growth of mold or organisms that can release harmful substances into the air flow, potentially causing unhealthy conditions in the building. Liquid water can also cause rusting of a duct which can lead to duct failure, and can create leaks from the duct to the building interior spaces which are unsightly, can cause a slipping hazard, and can lead to water damage to the structure. 
   One known humidification method involves direct steam injection into an air duct of a building. This approach is most commonly used in commercial buildings where a steam boiler is present to provide a ready supply of pressurized steam. Steam humidification has the advantage of having a relatively low risk of liquid moisture entering a duct or other building space. However, pressurized steam injection systems are associated with a risk of explosion of the steam pressure vessels, as well as a risk of possibly burning nearby people, both of which are very serious safety concerns. In residential applications, there are usually no readily available sources of pressurized steam. An open bath humidifier system may be used, however these are difficult to install because they require a large hole in the duct and can only be used with horizontal or upflow ducts. Alternatively, a residential application may use direct steam injection that requires a separate unit to generate pressurized steam and this separate unit is costly. Moreover, the system would suffer from the same disadvantages as are present in commercial direct steam injection systems. 
   One type of humidifier that is commonly used in residential applications that has the advantages of steam humidification without the need for a separate source of pressurized steam is a tank heater type humidifier that generates steam with little or no pressure. In this type of humidifier, heat is generated within a tank of water, causing the water to boil and steam to be generated. The heat input may be any of a number of different sources, however, commonly an electrical heating element is used. One problem associated with this type of humidifier is that as water is boiled off as steam, the impurities in the water remain in the tank. These impurities generally include minerals that are naturally occurring in most sources of water. Over time, the concentration of these impurities will tend to increase in the tank, leading to greater amounts of impurities that solidify and deposit on the surfaces inside the tank. These deposits can accumulate to the point of creating numerous problems. For example, deposits on a heating coil reduce the heat transfer rate to the water, resulting in lower steam production and possibly causing overheating and failure of the coil. Deposits in the tank can clog passages where water or steam flows in or out, resulting in the failure of the humidifier. It is therefore necessary for a user of a humidifier to occasionally remove the tank of the humidifier and manually clean the tank and associated components to remove the deposits and accumulations. 
   Improved constructions for humidification systems are desired. In particular, improved constructions for water tanks of steam humidifiers are needed, and specifically, constructions that permit the tank to be readily removed for cleaning. 
   SUMMARY OF THE INVENTION 
   The present disclosure relates to a water tank quick assembly feature for a steam humidifier. In one aspect of the invention, a steam humidifier is disclosed. The steam humidifier includes a removable tank, where the removable tank is configured to contain water to be heated to generate steam and a handle that is configured to selectively secure the removable tank to the humidifier. The handle defines at least a first rotational position in which a tank support feature on the tank is engaged with a handle support feature on the handle such that the tank is attached to the humidifier. The handle further defines at least a second rotational position in which the tank support feature is disengaged from the handle support feature such that the tank is unattached from the humidifier. 
   Another aspect of the invention relates to a steam humidifier having a main structure that is configured to be attached to a building structure and a tank for containing water and a heating element for heating the water in the tank to generate steam. The tank includes an upper structure that is secured to the main structure, a lower structure that is configured to mate with the upper structure to form an enclosed volume of the tank, a pair of tank pivot points located on the upper structure, and a pair of tank arc structures on the lower structure, where each tank arc structure is proximate to each pivot point. The steam humidifier further includes a handle having a pair of handle pivot points that are configured to engage the tank pivot points and that have a pair of handle arc structures configured to be engageable with the tank arc structures. The handle has at least a first rotational position in which the handle arc structures are engaged with the tank arc structures such that the tank lower structure is supported by the main structure, and a second rotational position in which the handle arc structures are disengaged from the tank arc structures such that the tank lower structure is free from the main structure. 
   An additional aspect of the invention relates to a method of removing a tank from a steam humidifier. The method includes rotating a handle from a first position to a second position, where in the first position a support feature on the tank is engaged with a support feature on the handle such that the tank is attached to the steam humidifier, and in the second position the support feature on the tank is disengaged from the support feature on the handle such that the tank is unattached from the humidifier. The method further includes separating the tank from the humidifier. 
   The invention may be more completely understood by considering the detailed description of various embodiments of the invention that follows in connection with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a cross-sectional view of a tank heater type steam humidifier. 
       FIG. 2  is a schematic representation of a HVAC system having a humidifier. 
       FIG. 3  is a schematic representation of a control system of a humidifier. 
       FIG. 4  is a front side perspective view of a humidifier having a water tank with a quick connection feature constructed according to the principles of the present invention. 
       FIG. 5  is a side perspective view of the humidifier of  FIG. 4  with the handle removed to show details of the construction of a tank support feature of the quick connection feature. 
       FIG. 6  is a close-up side perspective view showing details of the tank support feature of the quick connection feature. 
       FIG. 7  is a top perspective view of a humidifier having a handle and a handle locking feature. 
       FIG. 8  is a top view of the humidifier of  FIG. 7  with the handle removed to show details of the handle locking feature. 
       FIG. 9  is a perspective view of the handle of the humidifier of  FIG. 4 . 
       FIG. 10  is a close-up perspective view showing details of one tank support feature of the handle. 
       FIG. 11  is a top perspective view of an open top container. 
       FIG. 12  is a side perspective view of a humidifier having a cover removed to show a steam tube and steam dome. 
       FIG. 13  is an exploded perspective view of an open top container removed from a humidifier with the handle in an unlocked position. 
   

   While the invention may be modified in many ways, specifics have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives following within the scope and spirit of the invention as defined by the claims. 
   DETAILED DESCRIPTION OF THE INVENTION 
   As described above, minerals, sediments, and other impurities present in water tend to deposit in the tank of a tank heater type humidifier over the course of its operation. These deposits can build up and cause damage and interfere with the proper functioning of the humidifier. The rate at which these deposits form depend on a number of variables, including the mineral content of the water (hardness) and the amount of time that the humidifier is operated. It is generally recommended or required that the user of a humidifier disassemble and manually clean the tank and associated parts at a regular interval, such as every year. In some cases, a humidifier may provide an indication to the user that the tank needs to be cleaned. If the tank is not cleaned, deposits can accumulate to the point of clogging the drain, either reducing the efficiency of the drain or preventing the tank from draining all together. It is therefore desirable that the user of a humidifier remove the tank at regular intervals and manually clean it to remove the deposits and accumulations. 
   An embodiment of a tank heater type humidifier is depicted schematically in  FIG. 1 . Humidifier  20  includes a tank  22  configured to retain a volume of liquid water. Tank  22  is generally constructed out of material that is sufficiently resistant to high temperatures, such as the temperature of boiling water. Examples of suitable materials for tank  22  are temperature resistant plastics, an example of which is a thermoplastic resin such as a polyphenylene ether/polystyrene blend, and stainless steel. In one embodiment, components of tank  22  are formed by injection molding. A heating coil  24  is also provided to heat water within tank  22 . Heating coil  24  is generally an electric heating coil that generates heat when an electric current is passed through a resistive material. However, other types of heating coils  24  are usable. For example, heating coil  24  could pass a heated material such as a heated liquid through a tube that allows heat to transfer to the liquid in the tank  22 . Furthermore, a heater may be substituted for heating coil  24 , where a heater is of a conventional liquid heating design, such as a propane or natural gas liquid heater or a fuel oil burner. 
   Tank  22  is shown in  FIG. 1  as having an isolated chamber  26  that is separated from a main chamber  30  of tank  22  by baffle  28 . Isolated chamber  26  is in fluid communication with main chamber  30  by way of opening  32  which allows liquid from main chamber  30  to flow into isolated chamber  26  and to reach the same fluid level as in main chamber  30 . Isolated chamber  26  tends, however, to be insulated from ripples, bubbles, and other fluctuations of the water level in main chamber  30 , and therefore is a suitable location for measuring the water level in tank  22 .  FIG. 1  also shows that a high level water sensor  34  and a low level water sensor  36  are present within isolated chamber  26 . Low level sensor  36  detects the presence of water at a first level and high level sensor  34  detects the presence of water at a second level, where the first level is lower than the second level. Each of sensors  34 ,  36  is configured to detect the presence of water at the particular sensor. Sensors  34 ,  36  may be a current-detection type of sensor, where a source of current such as alternating current is applied at a point in the tank that is below both sensors  34 ,  36  and where sensors  34 ,  36  are configured to detect the presence of current which indicates a current path from the source of current, through the water, to sensors  34 ,  36 . Humidifier  20  further includes a tube  38  that projects from main tank chamber  30  to the interior of an air duct  40  and that provides a fluid connection for the flow of steam from main tank chamber  30  to the interior of air duct  40 . 
   Humidifier  20  includes a fill valve  42  and a drain valve  44 . Fill valve  42  is in fluid communication through conduit  54  with a water supply  46 , such as a municipal water supply system or a well pump system. Drain valve  44  is in fluid communication through a conduit  56  with a water receiving system  48 , such as a municipal water treatment system, a septic system, or a drain field. Humidifier  20  further includes a controller  52  that is in communication with water level sensors  34 ,  36  and has the ability to control the fill and drain valves  42 ,  44 . Controller  52  also includes one or more timers configured to measure elapsed times. 
   A typical heating, ventilation, and air conditioning (HVAC) installation that includes a humidifier is depicted in  FIG. 2 . Conditioned space  200  of a building is configured to receive conditioned air from supply duct  202  and to provide for return air flow through return duct  204 . Conditioned space  200  includes at least one thermostat  206  that is in communication with conditioning device  208 . Conditioning device  208  may be a furnace, a boiler, an air conditioner, a heat exchanger, or a combination thereof, that is configured to condition return air from return duct  204  and deliver the conditioned air to supply duct  202 . Conditioning air may involve increasing the temperature of the air, decreasing the temperature of the air, cleaning the air, or other such processes. Conditioning device  208  generally includes a fan or blower for drawing air from return duct  204  and delivering air through supply duct  202 . Thermostat  206  senses the temperature in conditioned space  200  and activates conditioning device  208  when the temperature deviates from a set value. When conditioning device  208  is activated by a call for conditioning from thermostat  206 , conditioned air is supplied through supply duct  202  to adjust the temperature of conditioned space  200  until the temperature sensed by thermostat  206  satisfies a set value. In some embodiments, thermostat  206  may be configured to receive an input to run a fan or blower without temperature conditioning of the air. In this case only the fan or blower portion of conditioning device  208  is activated and air is supplied through supply duct  202  without being conditioned by conditioning device  208 . 
     FIG. 2  also shows a typical installation of humidifier  20 . Humidifier  20  is installed on supply duct  202  downstream of conditioning device  208 . A humidistat  210  is installed in conditioned space  200  or within return duct  204  and is in communication with humidifier  20 . One embodiment of a humidistat  210  senses the relative humidity level (RH) present in conditioned space  200  and activates humidifier  20  when the humidity level falls below a set value. Other embodiments of humidistat  210  sense indoor dewpoint or even outdoor dewpoint in combination with either indoor RH or indoor dewpoint. In some embodiments, the thermostat  206  will incorporate the functionality of humidistat  210 . When humidifier  20  is activated, humidity is added to conditioned air within supply duct  202  in order to increase the humidity in conditioned space  200 . In some embodiments, humidifier  20  and/or humidistat  210  are configured to activate humidifier  20  only when conditioning device  208  is activated. This ensures that air is flowing through supply duct  202  to carry the additional humidity to conditioned space  200 . If humidifier  20  is activated without air flowing in supply duct  202 , the additional humidity provided by the humidifier may condense on the walls of the duct and cause damage, and the additional humidity will also not be effectively delivered to conditioned space  200 . In other embodiments, the conditioning device  208  will be activated any time there is a demand for humidification from humidistat  210 . 
   In operation of humidifier  20 , as can be understood from  FIG. 1 , when there is a call for humidification, humidifier  20  is filled by opening fill valve  42  to allow water from supply  46  to flow through conduit  54  into main chamber  30  of tank  22  and to isolated chamber  26 . Fill valve  42  will remain open until water is detected at high water sensor  34 , at which point fill valve  42  is closed. In some embodiments, an overfull sensor is provided to detect water above the high water sensor  34 , in which case the fill valve  42  would also be closed if water is detected. This feature is useful in the event of a failure of the high level sensor  34 . Heating coil  24  is then energized, causing the temperature of the water in tank  22  to increase. In some embodiments, water tank  22  is filled prior to there being a demand for humidification, such as at installation or system start-up, and the system then waits for a call for humidification to energize the heating coil  24 . As the water in tank  22  is heated, the water in tank  22  will begin to boil and steam will form at the top  50  of tank  22 . In some embodiments, a very slight pressure will be established in the top area  50  of tank  22 , driving steam through tube  38  and into duct  40 . Tube  38  is configured to allow sufficient steam to flow into duct  40  that very little pressure will build in tank  22 . In other embodiments, no pressure builds in tank  22  and steam is carried by convection into duct  40 . The steam enters the air in duct  40  where it is carried to conditioned spaces within a building. As water is converted to steam, the water level in tank  22  will decrease. With sufficient operation, the water level will drop below the height of low water level sensor  36 . When water falls below the height of low level sensor  36 , fill valve  42  will be opened and remain open until water reaches high level sensor  34 , at which point fill valve  42  will again be closed. 
   An embodiment of the components of a control system of humidifier  20  is depicted in  FIG. 3 . As shown in  FIG. 3 , controller  52  is in communication with high level sensor  34  and low level sensor  36 . Controller  52  therefore receives signals representative of whether the water level in tank  22  is at or above low level sensor  36  and whether the water level in the tank  22  is at or above high level sensor  34 . Controller  52  is further in communication with fill valve  42  and drain valve  44 , and is able to control the operation of each. Controller  52  is also shown in  FIG. 3  as being in communication with indicator  58 . Indicator  58  may be used to communicate information to a user, such as the need to clean the tank. Controller  52  also has an input device  60 , such as a switch or button or touch screen configured to receive input from a user, such as to indicate that the humidifier has been cleaned. 
     FIG. 4  is a front and side perspective view of a humidifier having a tank with a quick connection feature that allows the tank to be removed for cleaning in an expedient manner and without requiring the use of special tools or training. This arrangement is particularly advantageous because the typical humidifier user who has to remove the tank for cleaning is a homeowner or other person who does not have special training, may not want to spend much time learning how to perform a complicated procedure to remove a tank, and may not have ready access to tools for removing the tank. The tank quick connection feature is relatively easy to use because the user can, with one hand, support the tank, and with the other hand, rotate the handle to cause the tank to be released from the humidifier. 
   The humidifier  20  depicted in  FIG. 4  includes a main structure  150  that is configured to be mounted to a duct or other attachment point within a building. Main structure  150  may consist of a single piece or may be formed from several pieces that are attached or secured or structurally connected to each other. In one embodiment, main structure  150  is formed by injection molding. In another embodiment, main structure  150  is formed by several injection molded components that are configured to interact to provide a support structure. As shown in  FIG. 12 , main structure  150  also includes a structure for receiving steam tube  38 , such as a steam dome  152 , such that steam tube  38  is in fluid communication with tank  22 . Tank  22  is partially defined by main structure  150  that forms an upper boundary of tank  22 , and the remainder of tank  22  is defined by open top container  156 . Open top container  156  is assembled to main structure  150  to form a watertight and steamtight enclosed volume that constitutes tank  22 . For example, a seal such as an o-ring seal may be provided between open top container  156  and main structure  150  to form a watertight and steam tight enclosed volume. A top perspective view of open top container  156  is shown in  FIG. 11 . In some embodiments, open top container  156  is formed by injection molding. 
   The quick connection feature of tank  22  allows the tank to be readily removed and serviced. The connection of the open top container  156  to the main structure  150  is controlled by the position of handle  158 . When handle  158  is in the position shown in  FIG. 4 , open top container  156  is held securely against main structure  150 . In this case, handle  158  is said to be in the closed or locked position. A perspective view of the interface between open top container  156  and main structure  150  is shown in  FIG. 5 , where the handle is not shown. A seal is placed between open top container  156  and main structure  150  and is compressed by the force applied by handle  158  to create the watertight and steamtight enclosure that constitutes tank  22 .  FIG. 13  shows a view of handle  158  in the open or unlocked position. In this position, open top container  156  can be removed from main structure  150 , such as for cleaning. 
   A portion of main structure  150  is formed by upper cover  162 . Upper cover  162  serves to hide from view and protect various functional components that are mounted to main structure  150 . For example, there may be valves, relays, electronic controls, and wiring that are hidden and protected by upper cover  162 .  FIG. 12  shows humidifier  20  with upper cover  162  and handle  158  removed. As seen in  FIG. 7 , a locking button  164  is incorporated into or attached to upper cover  162 . Locking button  164 , also called a locking tab  164 , serves to secure handle  158  in the closed or locked position. Because handle  158  controls whether open top container  156  is secured to main structure  150 , and because during normal operation open top container  156  contains boiling water, it is desirable to have a feature such as locking button  164  to prevent handle  158  from inadvertently being unlocked and releasing open top container  156 . 
   Locking button  164  is also shown in  FIG. 8 , with handle  158  removed for clarity. In the depicted embodiment, locking button  164  includes a cantilevered section  168  that is attached at an end  170  to upper cover  162  and that is separated from upper cover  162  along sides  172 ,  174 ,  176 . Proximal to side  176  is a serrated protrusion  178 . Cantilevered section  168  is constructed from a material and with a thickness that it is capable of flexing, such as when a force is applied to serrated protrusion  178  by a person&#39;s finger. When handle  158  is in the locked position, as shown in  FIG. 7 , locking protrusion  182  on handle  158  engages notch  180  on button  164 . In this position, handle  158  cannot be rotated forward to unlock open top container  156  because it is secured in place by notch  180 . However, when it is desired to release open top container  156 , the user presses downward on serrated protrusion  178  to cause cantilevered section  168  to flex and be forced downward, causing notch  180  to be moved below protrusion  182  allowing movement of handle  158 . Handle  158  can then be rotated forward to release open top container  156 . 
   As discussed above, the position of handle  158  controls the connection of the open top container  156  to the main structure  150 . Handle  158  generally rotates about an axis of rotation that is defined by a pair of pivot points on each side of the humidifier.  FIGS. 5 and 6  depict an embodiment of pivot points  300  for handle  158 . Only one side is shown in  FIGS. 5 and 6 ; the other side is generally a mirror image of the depicted features. Pivot points  300  are located on, or are structurally linked to, main structure  150 . As seen in  FIG. 9 , handle  158  has corresponding pivot points  302  that are configured to engage pivot points  300 . A variety of configurations are usable for pivot points  300 ,  302 . As shown in  FIGS. 5 and 9 , in one embodiment pivot points  300  are cylindrical openings and pivot points  302  are cylindrical protrusions. In another embodiment, pivot points  300  are protrusions and pivot points  302  are openings. There is generally one pivot point  300  and one pivot point  302  associated with one side of the humidifier and another pivot point  300  and pivot point  302  associated with the other side of the humidifier. Together, these features define an axis of rotation of the handle  158  about the main structure  150 . 
   Handle  158  controls the connection of the open top container  156  to the main structure  150  by way of support features that are present at least on the open top container  156  and handle  158 . An example embodiment of the support features on open top container  156  is shown in  FIG. 5  and an example embodiment of the support features on handle  158  is shown in  FIG. 9 . Only one side is shown in  FIGS. 5 and 9 ; the other side is generally a mirror image of the depicted features. As seen in  FIG. 5 , the support feature on the open top container  156  is an arc-shaped protrusion  320 . Arc-shaped protrusion  320  is generally defined by a radius R 1  having a center near, but generally not the same as, the axis of rotation of the handle as defined by the pivot point  300 . Radius R 1  defines a first surface  322  of protrusion  320 . A radius R 2  also has a center near but generally not at the axis of rotation of the handle as defined by the pivot points  300 . Radius R 2  defines a second surface  324  of protrusion  320 . By virtue of the radii R 1  and R 2  not having the same center as the axis of rotation of the handle, then as the handle is rotated a cam action will occur tending to cause protrusion  320  to be drawn upward toward pivot point  300 . The radii R 1 , R 2  need not be exactly constant along the length of the arc-shaped protrusion  320 , but instead may be slightly variable. Arc shape protrusion  320  is also defined by an arc length L 1  that is the length from one end of the arc shaped protrusion to the other. The arc shaped protrusion  320  has a first end  326  and a second end  328 . 
   An embodiment of the corresponding support features on handle  158  is shown in  FIGS. 9 and 10 . The support features on the handle  158  are arc-shaped grooves  340 . On each side of the handle, an arc-shaped groove  340  is defined by a radius R 3  having a center near but generally not at the axis of rotation of the handle as defined by the pivot point  302 . Radius R 3  defines a first surface  342  of groove  340 . In addition, a radius R 4  exists having its beginning at a center near but generally not at the axis of rotation of the handle as defined by the pivot point  302  and ending at a second surface  344  of groove  340 . By virtue of the radii R 3  and R 4  not having the same center as the axis of rotation of the handle, then as the handle is rotated a cam action will occur tending to cause protrusion  320  to be drawn upward toward pivot point  300 . The radii R 3 , R 4  need not be exactly constant along the length of the arc-shaped protrusion  320 , but rather may vary, and are generally similar to, or compatible with, radii R 1 , R 2  of arc-shaped protrusions  320 . Arc shape grooves  340  are defined by an arc length L 2  that is the length from the open end  346  of the arc shaped groove to the closed end  348 . The length L 2  is generally configured to at least allow the arc shaped protrusions  320  to enter into the arc shaped grooves  340  and to allow the handle  158  to be rotated through its complete desired range of motion. 
   In some embodiments, an arc shaped protrusion  320  includes an alignment feature intended to promote the alignment of open top container  156  to upper structure  150 . In the embodiment of  FIG. 5 , arc shaped protrusion  320  includes an alignment tab  330  that is a crescent- or triangular-shaped protrusion extending from second end  328 . Main structure  150  includes a corresponding alignment tab receiver  332 . Alignment tab receiver  332  is configured to receive alignment tab  330 , and in one embodiment has a generally crescent- or triangular-shaped configuration. In use, when the user raises the open top container  156  toward the upper structure  150 , alignment tab  330  will enter into alignment tab receiver  332 . Because the smaller, pointed end of alignment tab  330  first enters the relatively wider opening of alignment tab receiver  332 , initial alignment of the pieces is relatively easy for the user to accomplish. As the open top container  156  is raised further and becomes closer to upper structure  150 , the converging walls of the alignment tab receiver  332  will force alignment tab  330  into the proper orientation, and thereby cause the open top container  156  to be correctly aligned to main structure  150 . 
   In use, the handle  158  is manipulated by a user when the user intends to remove the open top container  156  for a reason such as to clean it. In some embodiments, the user may first perform various operations, such as providing an input to a button or a switch to indicate to the humidifier that the open top container  156  is about to be removed. This step may be useful for reasons such as allowing the humidifier controls to de-energize the heating element and to drain the water out of the tank. In some embodiments, the user may detach the water connections from the open top container  156 , such as the water supply and water drain connections. When the open top container  156  is ready to be removed, the user first presses locking button  164  while simultaneously rotating handle  158  forward, toward the front of the humidifier. This action can be performed with one hand of the user because of the proximity of the locking button  164  to the handle  158 . Simultaneously, the user supports the open top container  156  with his or her other hand. 
   As the locking button  164  is pressed down, it clears the handle  158  and allows the handle to be rotated forward. The handle rotates around pivot points  300 ,  302 , and in doing so, causes the arc shaped grooves  340  to rotate relative to the open top container  156  and the arc-shaped projections  324  thereon. This relative rotation causes the arc-shaped projections  324  to become disengaged from the arc shaped grooves  340  upon sufficient rotation of handle  158 . When arc-shaped projections  324  are disengaged from arc shaped grooves  340 , the mechanical support of open top container from main structure  150 , through pivot points  300 ,  302 , to handle  158 , and to arc-shaped grooves  340  and arc-shaped projections  324  is broken. The open top container  156  can now be removed from main structure  150 . The open top container  156  is shown removed from main structure  150  in  FIG. 13 . 
   When it is desired to reinstall open top container to main structure  150 , the user positions handle  158  in a forward position, such as the position where it was left when the open top container  156  was disengaged, and then raises open top container  156  toward main structure  150 . The user generally aligns alignment tab  330  with alignment tab receiver  332 , such that the projection of alignment tab  330  enters into alignment tab receiver  332  and brings open top container  156  into alignment with main structure  150 . The user holds open top container  156  against main structure  150  with one hand, while with the other hand rotating handle  158  toward the rear of the humidifier. In doing so, the arc-shaped grooves  340  on handle  158  are rotated into engagement with the arc shaped projections  324  on open top container  156 . Handle  158  is rotated until the cam action of the arc-shaped projections  324  and the arc-shaped grooves  340  causes the open top container  156  to be drawn tightly against main structure  150 , at which point locking button  164  locks it in place, thereby securing open top container  156  to main structure  150  by way of arc shaped projections  324  and arc shaped grooves  340 , pivot points  300 ,  302 , and handle  158 . 
   Various components of the present invention are advantageously formed by injection molding. For example, open top container  156 , handle  158 , and main structure  150  may be formed by injection molding. Injection molding allows the various features, including support features, such as arc-shaped protrusion of open top container  156 , or arc-shaped grooves  340  of handle  158 , or pivot points  300  of main structure  150 , to be formed integrally and in a single step with the formation of the base component. 
   The present invention should not be considered limited to the particular examples described above, but rather should be understood to cover all aspects of the invention as fairly set out in the attached claims. Various modifications, equivalent processes, as well as numerous structures to which the present invention may be applicable will be readily apparent to those of skill in the art to which the present invention is directed upon review of the present specification. The claims are intended to cover such modifications and devices. 
   The above specification provides a complete description of the structure and use of the invention. Since many of the embodiments of the invention can be made without parting from the spirit and scope of the invention, the invention resides in the claims.