Abstract:
An induction humidification system is disclosed. The induction humidification system includes a base having a circumferential induction coil and a removable and replaceable cartridge received within the interior space defined by the induction coil. The canister has a nonmetallic housing, such as a plastic housing, within which a ferromagnetic member having a circumferential sidewall is disposed. When the canister is received within the base, the ferromagnetic member sidewall and the induction coil are radially overlapping such that a current applied to the induction coil causes the ferromagnetic member to be heated which in turn causes water held within the canister to be converted to steam. Once the ferromagnetic member has reached the end of its useful life, the canister can be simply replaced with a new canister that can be received by the original base.

Description:
RELATED APPLICATION 
       [0001]    This application claims priority to U.S. Provisional Patent Application Ser. No. 62/266,337, filed on Dec. 11, 2016, the entirety of which is incorporated by reference herein. 
     
    
     BACKGROUND 
       [0002]    There are many ways to generate steam for humidification purposes. For example, electrode-type humidifiers produce a small to moderate amount of steam at low pressure (usually atmospheric). In this type of system, electrodes are placed in a plastic tank and electricity is applied to the electrodes directly located in water. As typical water conducts electricity, the water is heated and caused it to boil as the electricity travels through the water between the electrodes. Electrode humidifiers have inherent steam output control limitations. Operation is dependent upon and varies with the water conductivity. Steam output is controlled by draining and filling with water, which adjusts water conductivity and water level. Very low conductivity water such as RO (reverses osmosis) and DI (deionized) renders an electrode humidifier virtually inoperable 
         [0003]    Electrode humidifiers also require that any connected drain lines either be physically separated from the electrically charged water or that the electrodes be turned off the prevent shock hazards during draining. However, electrode humidifiers are typically lower cost than other steam humidifiers, fail safe under low/no water conditions and have replaceable tanks with electrodes for easier maintenance. 
       SUMMARY 
       [0004]    As described above, electrode humidifiers have a combination of limitations and advantages compared to other steam humidifiers. What is needed in the art is a new steam humidifier that utilizes a replaceable tank like an electrode humidifier combined with excellent steam control independent of water conductivity. The induction humidifier system disclosed herein represents such an improvement. 
         [0005]    In one aspect, the humidification system includes a base and a replaceable canister received by the base. The canister has a nonmetallic housing having a circumferential sidewall defining an interior volume. The circumferential sidewall can extending between a bottom drain-fill port for receiving liquid water and a top discharge port for discharging steam. The canister also includes a ferromagnetic member located within the interior volume of the housing. The ferromagnetic member has a circumferential sidewall that has a complementarily shape with the housing circumferential sidewall. The ferromagnetic member can also be provided with a central aperture in fluid communication with the housing drain-fill port. In one aspect, the ferromagnetic member circumferential sidewall and the housing sidewall are radially overlapping, but spaced apart. 
         [0006]    The base of the induction humidifier is provided with a circumferential sidewall that defines an interior volume into which the canister housing is received. The base has an induction coil located within the circumferential sidewall that is connected to a power source and control system. When the canister is received into the base, the ferromagnetic member circumferential sidewall is radially overlapping with the induction coil such that when power is applied to the induction coil, the ferromagnetic member is heated which in turn causes water surrounding both sides of the ferromagnetic member to be heated and turn to steam. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0007]    Non-limiting and non-exhaustive embodiments are described with reference to the following figures, which are not necessarily drawn to scale, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified. 
           [0008]      FIG. 1  is a schematic exploded view of a first embodiment of an induction humidification system having features that are examples of aspects in accordance with the principles of the present disclosure. 
           [0009]      FIG. 1A  shows a ferromagnetic member usable in the humidification system shown in  FIG. 1 . 
           [0010]      FIG. 1B  shows a ferromagnetic member usable in the humidification system shown in  FIG. 1 . 
           [0011]      FIG. 1C  shows a ferromagnetic member usable in the humidification system shown in  FIG. 1 . 
           [0012]      FIG. 1D  shows a ferromagnetic member usable in the humidification system shown in  FIG. 1 . 
           [0013]      FIG. 1E  shows a ferromagnetic member usable in the humidification system shown in  FIG. 1 . 
           [0014]      FIG. 1F  shows a ferromagnetic member usable in the humidification system shown in  FIG. 1 . 
           [0015]      FIG. 1G  shows a ferromagnetic member usable in the humidification system shown in  FIG. 1 . 
           [0016]      FIG. 2  is a top view of the induction humidification system shown in  FIG. 1 . 
           [0017]      FIG. 3  is a section view of the induction humidification system shown in  FIG. 2 , taken along the line  3 - 3  in  FIG. 2 . 
           [0018]      FIG. 4  is a section view of an enlarged portion of the view of the induction humidification system shown in  FIG. 3 . 
           [0019]      FIG. 4A  is a schematic section view of the induction humidification system shown in  FIG. 1 , utilizing the ferromagnetic member of  FIG. 1F . 
           [0020]      FIG. 4B  is a schematic section view of the induction humidification system shown in  FIG. 1 , utilizing the ferromagnetic member of  FIG. 1G . 
           [0021]      FIG. 5  is a side view of the canister of the induction system shown in  FIG. 1 . 
           [0022]      FIG. 6  is a schematic view of a control circuit for the induction humidification system shown in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    Various embodiments will be described in detail with reference to the drawings, wherein like reference numerals represent like parts and assemblies throughout the several views. Reference to various embodiments does not limit the scope of the claims attached hereto. Additionally, any examples set forth in this specification are not intended to be limiting and merely set forth some of the many possible embodiments for the appended claims. 
         [0024]    Referring to  FIGS. 1 to 4  in the drawings, an induction humidification system  100  is presented. The induction humidification system  100  is for converting water to steam through an induction process in which an induction coil heats a target element in contact with the water. As shown at  FIG. 1 , the induction humidification system  100  includes a canister  110  having an upper half  112  and a mating lower half  114 , a base  118  into which the canister  110  is received, and a ferromagnetic member  116  installed within the canister  110  that acts as a target material for an induction coil (see  122  at  FIG. 4 ) integrated into the base  118 . In some embodiments, the ferromagnetic member  116  is provided with a three-dimensional shape, such as a cylindrical tube-shape or a cup-shape. 
         [0025]    The base  118  of the induction humidification system  100  is shown in more detail at  FIG. 4  in the drawings. As shown, the base  118  is generally formed in a bowl or a hollow hemispherical shape with an interior portion  118  defined by a circumferential sidewall  120 . By use of the term “circumferential sidewall” it is meant to indicate a sidewall that is curved, bent, segmented, or otherwise shaped to define a generally enclosed circumference or perimeter such an interior space or volume within the sidewall can be defined. Many examples of a circumferential sidewall meeting this definition exist. For example, a circumferential sidewall can be curved or segmented in the radial and axial directions to generally form a hollow hemispheric or bowl shape. A circumferential sidewall can also be tapered in the axial direction and curved or segmented in the radial direction to form various shapes, such as a generally conical or frustoconical shape. A circumferential sidewall can also be formed to define a prismatic shape with any number of adjoining planar sidewall segments such as triangular, rectangular, and pentagonal prisms. A circumferential sidewall can also be formed to have a curved cross-sectional shape, such as a circular, elliptical, or oblong shape. A circumferential sidewall can also be formed from multiple adjoining planar segments disposed at a non-zero angle with respect to each other in the radial and/or axial direction. Combinations of the above noted examples can also be utilized to form a circumferential sidewall. 
         [0026]    In the example presented in the drawings, the base  118  is defined entirely by the circumferential sidewall  120  which is formed by three adjoining radially curved portions  120   a ,  120   b ,  120   c . The third portion  120   c  defines a central aperture  134  through which a drain-fill port  128  of the canister  110  can extend. As shown, the portion  120   a  is very slightly tapered while portions  120   b  and  120   c  are increasingly tapered, wherein each portion has a frustoconical shape. The overall shape defined by the portions  120   a ,  120   b , and  120   c  can be referred to as a bowl shape or a segmented bowl shape that defines the interior  118 . In an alternative arrangement, the sidewall  120  could be formed more simply as a cylindrical shape that is joined by a closed or partially closed end wall (not shown) to form the base  118 . However, the configuration shown has beneficial aspects in that it provides a greater opening area for initially receiving the canister  110  and then tapers to guide the canister  110  into the fully received position. 
         [0027]    As stated previously, an induction coil  122  is embedded into the sidewall  120  of the base  118 . As such, the induction coil  122  has the same general shape as the sidewall  120  and can be said to have sidewall portions  122   a ,  122   b , and  122   c  corresponding to portions  120   a ,  120   b , and  120   c  of the sidewall  120 . As shown, the induction coil  122  is formed from a continuously wound wire  124 , the ends of which are connected to a power source which supplies an alternating current to generate a magnetic field. In one example, a bare copper wire  124  is first wound into the desired shape to form the induction coil  122  which is then placed into a mold. A nonmetallic material, such as a plastic, can then be introduced into the mold to encompass the induction coil  122  and form the base sidewall  120 . After curing, a base  118  having an embedded induction coil  122  can be removed from the mold. When an electric current is applied to the induction coil  122  the electromagnetic field will be directed towards the interior  118  of the base  118 . Other configurations can also be utilized in which the coil  122  is not embedded into another material. 
         [0028]    Referring back to  FIG. 1 , it can be seen that the first housing part  112  is provided with a discharge port  126  while the second housing part  114  is provided with a drain-fill port  128 . Each of the first and second housing parts  112 ,  114  are formed from a nonmetallic material, such as a plastic. Accordingly, the magnetic field generated by the induction coil  122  will pass through the housing parts  112 ,  114  without causing them to be heated. The first and second housing parts  112 ,  114  can be mated together at their respective open ends  112   a ,  114   a  to form an interior space or volume  130 . The parts  112 ,  114  can be either permanently joined or non-permanently joined. Non-limiting examples of a permanently joined connection are joining by welding (e.g. vibration, resistance, ultrasonic, laser, hot gas welding etc.), adhesives, or by fasteners that are incapable of being released once installed. Non-limiting examples of a non-permanently joined connection are joining by releasable fasteners, clamps, and latches. 
         [0029]    The first and second housing parts  112 ,  114  are also at least partially defined by a respective circumferential sidewall  136 ,  138 . The first housing part circumferential sidewall  136  extends between the discharge port  126  and the first housing part open end  112   a  while the second housing part circumferential sidewall  138  extends between the drain-fill port  128  and the second housing part open end  114   a . The second housing part circumferential sidewall  138  is complementarily shaped with the base circumferential sidewall  120  meaning that a majority of the radially overlapping portions of each (when the canister  110  is received into the base  118 ) are at least more parallel to each other than orthogonal. By use of the term “radially overlapping” it is meant that a line extending orthogonally from the central axis X of the system  100 /canister  110  will pass through both of the overlapping components. This complementarily shaped configuration allows the canister  110  to be fully received into the interior portion  118  defined by the base  118  such that the drain-fill port  128  extends through the central aperture  134  defined by the base  118  and such that the base circumferential sidewall  120  is radially overlapping with a portion of the second housing part circumferential sidewall  138 . 
         [0030]    As most easily seen at  FIG. 4 , the drain-fill port  128  can include a strainer  132 . The strainer  132  is for preventing debris from reaching the interior volume  130  of the canister  110  from a connected drain-fill line. As shown, the strainer  132  is a separate component that is inserted through the drain-fill port  128  and projects inwardly from the drain-fill port  128  into the interior volume  130  of the canister  110 . The strainer  132  is formed with a tubular or generally cylindrical shape with radially spaced slots  132   b  disposed in a circumferential sidewall  132   a . A flange is also provided at the open end of the strainer  132  such that the strainer  132  cannot be inserted too far through the drain-fill part. Other means for preventing contaminants from entering the interior volume may also be utilized, for example, screens, meshes, and filters. 
         [0031]    Before the housing parts  112 ,  114  are joined together, the ferromagnetic member  116  is installed into the second housing part  114 . The ferromagnetic member  116  forms a central aperture  140  through which the strainer  132  can project and through which water from the drain-fill port  128  can pass. The ferromagnetic member  116  can be formed from any material including ferromagnetic metals, for example, 400 series stainless steel and mild, medium, and high carbon steels. 
         [0032]    In one aspect, the ferromagnetic member  116  is provided with a circumferential sidewall  142  defining an interior space  146 . The circumferential sidewall is complementary in shape to the both the second housing part circumferential sidewall  138  and the base circumferential sidewall  120 . In one aspect, the circumferential sidewall  142  has parts  142   a ,  142   b , and  142   c  which are generally parallel to parts  120   a ,  120   b , and  120   c  of the circumferential sidewall  120  when the ferromagnetic member  116  is installed into the canister  110  and when the canister is installed into the base  118 . Accordingly, once these components are installed together, the circumferential sidewall  142  is radially overlapping with the induction coil  122 . This radial overlap enables the induction coil  122  to heat the ferromagnetic member  116  once a current is supplied to the induction coil  122  such that the ferromagnetic member  116  can in turn heat the water present in the canister  116  and convert the water to steam. 
         [0033]    The ferromagnetic member  116  is installed within the second housing part  114  such that a gap  144  exists between the cup-shaped sidewall  142  and the second housing part sidewall  138 . In one embodiment, the gap  144  is about ⅛ to ⅜ inches wide. Accordingly, a first side  142   e  of the sidewall  142  and an opposite second side  142   f  of the sidewall  142  are both in contact with the liquid water present in the canister  110 . This configuration effectively doubles the surface area of the ferromagnetic member  116  that can be used for heating the water, thus increasing the overall effectiveness of the system  100 . Additionally, the gap  144  provides an insulating space (i.e. air or water) to protect the second housing part  114  from being directly exposed to the heated ferromagnetic member  116 , which could melt the housing part  114  absent the gap  144 . The ferromagnetic member  116  is secured within the housing by attaching to side clips or press-fitting the member  116  onto the base  114 . The ferromagnetic member can be further secured with adhesives or fasteners to the base  114  to prevent free floating in the water and/or vibrating under an electromagnetic field. Water level control will control the amount of water in the volume  130  to prevent ferromagnetic member being energized without water. Water present in the gap  144  will absorb the heat and prevent the plastic housing  110  from overheating. 
         [0034]    The circumferential sidewall  142  can be provided with a continuous, solid circumferential sidewall  142  or can be provided in other configurations. For example, the circumferential sidewall  142  can be provided with slots extending between the central aperture  140  and the open end  116   a  of the member  116 . Additionally the circumferential sidewall could be formed from a mesh, screen, or an expanded metal, or could be otherwise perforated (i.e. via punching). Such features can allow for water to travel to both sides of the sidewall  142  to ensure water does not become trapped between the sidewall  142  and the second housing part  114 . Furthermore, the circumferential sidewall  142  can be provided with a relatively smooth surface, as shown, or can be provided with an enhanced surface. An enhanced surface is a non-smooth surface, such as one with ridges, bumps, indentations, embossed surfaces, and/or nucleation sites, provided to increase the contact surface area with the water for increased boiling performance. One example of an enhanced surface provided with nucleation sites usable for the circumferential sidewall  142  of the member  116  is shown and described in U.S. Pat. No. 8,505,497, issued Aug. 13, 2013, the entirety of which is incorporated by reference herein. 
         [0035]    In the example shown at  FIGS. 1 and 3-4 , the ferromagnetic member  116  is provided with a solid, impermeable metallic sidewall  142 . In the example shown at  FIG. 1A , a ferromagnetic member  116 ′ is shown in which the sidewall  142 ′ is formed form expanded metal, thereby providing a plurality of apertures  143 ′ in the sidewall  142 ′ through which water may flow. In the example shown at  FIG. 1B , a ferromagnetic member  116 ″ is shown in which the sidewall  142 ″ is formed form perforated metal, thereby providing a plurality of apertures  143 ″ in the sidewall  142 ″ through which water may flow. In the example shown at  FIG. 1C , a ferromagnetic member  116 ′ is shown in which the sidewall  142 ′″ is formed form perforated metal having an enhanced surface  145 ′, thereby providing a plurality of apertures  143 ″ in the sidewall  142 ″ through which water may flow. The enhanced surface may be of any of the types described above, including nucleation sites of the nature described in U.S. Pat. No. 8,505,497. 
         [0036]    With reference to  FIGS. 1D and 1E , the induction humidification system  100  may be configured such that only a portion of the sidewall  142  of the ferromagnetic member  116  is provided. For example,  FIG. 1D  shows a ferromagnetic member  117  including only the circumferential sidewall portion  142   a  while  FIG. 1E  shows a ferromagnetic member  119  including only the circumferential sidewall portions  142   b  and  142   c . Ferromagnetic member  119  could also be configured such that it only includes circumferential sidewall portion  142   c .  FIGS. 1F and 1G  show even further alternatives in which a ferromagnetic member  121  is formed as an entirely cylindrical sidewall portion  142   a  and in which a ferromagnetic member  123  is formed as a flat plate. Ferromagnetic member  121  can be differently shaped as well, for example, the ferromagnetic member can be provided with a frustoconical shape or a curved shape. Likewise, the ferromagnetic member  123  need not be a perfectly flat plate, but can be slightly angled or curved in some instances. For both ferromagnetic members  121  and  132 , the depicted embodiments are preferable from a manufacturability standpoint in that they are relatively simple shapes to produce from a metal sheet without requiring extensive fabrication steps. As previously discussed with respect to the ferromagnetic member  116 , the surfaces of the ferromagnetic members  117 ,  119 ,  121 , and  123  may be provided as described in reference to  FIGS. 1A to 1C . 
         [0037]    With reference to  FIG. 4A , a variation of the induction humidification system  100  is shown in schematic form in which the ferromagnetic member  121  is used instead of the ferromagnetic member  116 . In this example, the ferromagnetic member  121  is spaced away from the sidewall  138  of the housing part  114  such that the ferromagnetic member  121  can advantageously heat water on each side of the sidewall  142   a . The induction coil  122  is also shown as only including section  122   a  since there is no bottom portion associated with the ferromagnetic member  121 . The resulting structure is an induction coil  122  that is generally parallel to the sidewall  142  of the ferromagnetic member  121 . As shown in  FIG. 4A , the coil  122  and sidewall  142  are completely parallel and extend parallel to the longitudinal axis X. However, the sidewall  142   a  and coil  122  may be presented at an oblique angle to the axis X and may also be less than completely parallel to each other provided they are at least more parallel than not. 
         [0038]    With reference to  FIG. 4B , another variation of the induction humidification system  100  is shown in schematic form in which the ferromagnetic member  123  is used instead of the ferromagnetic member  116 . In this example, the ferromagnetic member  123  is spaced away from the sidewall  138  of the housing part  114  such that the ferromagnetic member  121  can advantageously heat water on each side of the sidewall  142   c . To provide this spacing, the sidewall  138  can be provided with stand-offs  180 . Alternatively, the ferromagnetic member  121  can be provided with stand-offs  180 . In one example, the stand-offs  180  are bent metal tabs that are an integral part of the ferromagnetic member  121 . The induction coil  122  is also shown as only including section  122   c  since there is no side portion associated with the ferromagnetic member  123 . The resulting structure is an induction coil  122  that is generally parallel to the sidewall  142  of the ferromagnetic member  121 . As shown in  FIG. 4B , the coil  122  and sidewall  142  are completely parallel and extend orthogonally to the longitudinal axis X. However, the sidewall  142   c  and coil  122  may be presented at an oblique angle to the axis X and may also be less than completely parallel to each other provided they are at least more parallel than not. 
         [0039]    The induction humidification system  100  may be provided with a control system or circuit  150  to control the operation of the induction coil  122  to obtain the desired steam output (i.e. boiling rate) and to ensure safe operation. Referring to  FIG. 6 , a schematic of an electronic drive control circuit  150  is shown in which, in very simple terms, an AC power source  152  is connected to a bridge rectifier module  154  to convert the AC input signal to a pulsating DC signal. The circuit  150  can also include an input line filter  156  (i.e. DC link filter) having a resistor  156   a  and capacitor  156   b . The circuit  150  further includes an induction circuit  158 , configured as a simple parallel resonant circuit (tank circuit), having the induction coil  122  and a capacitor  158   a . The circuit  150  can also be provided with a pulse width modulation (PWM) microcontroller  160  including an IGBT/MOSFET to control the duty cycle of the circuit  150 . 
         [0040]    To prevent the plastic canister  110  from melting, a low water lever sensor  172  can also be provided to ensure the ferromagnetic member  116  is not energized when the system is dry or there is not enough water. A high water level sensor  170  may also be provided to establish a maximum fill volume and to ensure that the water level is maintained at a level between the sensors  170 ,  172 . The water level sensors  170 ,  172  can also be utilized to ensure a certain fill level is maintained that corresponds to a specified amount of stored water. By monitoring the amount of power being sent to the induction coil  122 , an approximate boiling rate can be calculated based on the volume of water present at the fill level. Thus, the control circuit  150  can control the boiling rate of the system  100  to meet any desired set point by adjusting the power sent to the induction coil  122 . 
         [0041]    With the disclosed induction humidification system  100 , water conductivity and purity don&#39;t affect the boiling rate in a significant way. As such, RO and DI water can be used to eliminate mineral deposits within the cylinder, and especially on the ferromagnetic member  116 , eliminating some of the inherent design issues of electrode humidifiers. Additionally, as the water boils off within the canister  110 , the water conductivity increases. Since there is no electric current within the water, increased water conductivity has no effect to the performance of the disclosed humidifier. Therefore the otherwise necessary drain cycle can be reduced or eliminated. The reduction or elimination of drain cycle increases water efficiency of such systems. As disclosed, the induction humidification system  100  combines tight output control, RO/DI water capabilities, and the safety of electric resistive units with the replaceable tank features of electrode-type units. As such, the disclosed system  100  represents a significant advancement in humidifier technology. 
         [0042]    The various embodiments described above are provided by way of illustration only and should not be construed to limit the claims attached hereto. Those skilled in the art will readily recognize various modifications and changes that may be made without following the example embodiments and applications illustrated and described herein, and without departing from the true spirit and scope of the disclosure.