Abstract:
The present Invention relates to a humidifier that has a housing defining a chamber having at least one open end. The housing is provided with a gas inlet connectable in fluid communication with a source of gas having a first moisture content, and a gas outlet connectable with a passageway for the withdrawal of a gas having a second moisture content greater than the first moisture content. The humidifier also has at least one fluid distributing portion disposed within the at least one open end of the housing to continuously distribute a fluid within the chamber, and at least one baffle disposed within the housing to define a flow path for the gas to be humidified. During operation, the gas absorbs at least a portion of the fluid as the fluid is being continuously distributed in the chamber thereby increasing the moisture content of the gas as it travels from the gas inlet towards the gas outlet. Packing material can be provided in the housing to further increase the contact area between the gas and the water, if desired.

Description:
FIELD OF THE INVENTION 
     The present invention generally relates to a humidifier. More particularly, the present invention relates to a compact gas humidifying device having a long flow path and packing materials. 
     BACKGROUND OF THE INVENTION 
     There are a variety of devices used to humidify gases in domestic applications and industrial applications. Examples of known humidifying devices include bubbler humidifiers, packed column humidifiers, membrane humidifiers, etc. 
     One known type of humidifier uses water injection to humidify the gas. The humidifier has a generally hollow cylindrical body and a plurality of water injection nozzles for injecting water into the hollow cylindrical body. The water injection nozzles are typically provided on one side wall of the hollow cylindrical body. Dry gas enters the humidifier through a gas inlet provided at one end of the hollow cylindrical body and flows along the axial direction of the hollow cylindrical body to the opposite end. As the gas flows through the hollow cylindrical body water is injected into the hollow of the body through the plurality of injection nozzles, humidifying the gas. The humidified gas then leaves the hollow cylindrical body through a gas outlet provided at the opposite end of the hollow cylindrical body. The flow path of the gas is relatively short with little contact area between the gas and the water. In order to increase the flow path and contact area between the gas and the water the device tends to be large. 
     Another known type of humidifier uses a packing material to increase the contact area between the gas and the water. Examples of this type of humidifier have been disclosed in U.S. Pat. Nos. 3,983,190 and 5,769,067. The humidifier has a generally hollow cylindrical body and is disposed in a substantially vertical position. The gas enters the hollow cylindrical body from a gas inlet provided on a bottom wall of the hollow cylindrical body, and is forced to flow upwardly along the axial direction of the hollow cylindrical body by a blower or fan. A water inlet is provided on a top wall of the hollow cylindrical body to dispense water to a water distribution plate that is disposed within the hollow cylindrical body generally parallel to and near the top wall. A plurality of holes are provided in the water distribution plate so that water coming from the water inlet can drip down through the holes to humidify the gas flowing upwardly through the hollow cylindrical body. A packing material can be packed between the water distribution plate and the bottom wall to increase the contact area between the gas and the water. 
     A humidifier employing a water permeable membrane is disclosed in U.S. Pat. No. 5,348,691. Passages for the gas to be humidified and passages for water are provided on opposite sides of a membrane. As the gas flows along the passages on one side of the membrane water, flowing through the passages on the other side of the membrane, permeates through the membrane to humidify the gas. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, a humidifier is provided having a housing defining a chamber. The housing is provided with a gas inlet to the chamber and a gas outlet from the chamber and at least one fluid distributing portion connected to the housing to distribute a fluid within the chamber. At least one baffle is disposed within the chamber to define a flow path for the gas between the gas inlet and the gas outlet. The present invention is described using humidifying air with water as an example. It can be appreciated, however, that the present invention can also be used to humidify other gases or fluids and to exchange heat. 
     In one embodiment the at least one baffle comprises a plurality of baffles plates. In particular, the baffle plates are disposed within the chamber generally transverse to the fluid distributing portion and spaced from one another over a longitudinal extent of the fluid distributing portion. The extent of the baffle plates in the direction generally transverse to the fluid distributing portion is sufficient to define within the chamber gas flow paths adjacent the baffle plates. Each baffle plate can have a top edge and a bottom edge and a width, with the width being substantially the same as the width of the side walls of the chamber, that is to say, for the embodiment disclosed, the baffle plates extend from one side wall of the chamber to the other side wall. The baffle plates can be of various shapes and it is not necessary that the baffle plates be similar in shape and dimension to each other. For the embodiment disclosed the baffle plates have generally the same shape and dimension. 
     Each baffle plate is provided with an opening to allow gas to flow between adjacent flow paths. The opening of a given baffle plate is at an end of the baffle plate that is opposed to the end of where an opening of an adjacent baffle plate is provided. 
     In the embodiment disclosed the opening is provided by spacing an end of the baffle plate from at least one of the fluid distributing portions and the inner walls of the chamber. Moreover, adjacent baffle plates are positioned within the chamber so as to be offset with respect to one another in a direction generally transverse to the fluid distributing portion. This presents the opening of a given baffle plate in opposition to where an opening of an adjacent baffle plate is provided. 
     Moreover, at least some of the baffle plates can be provided with an aperture to allow fluid to flow between adjacent flow paths. 
     Further, the baffle plates can be disposed within the chamber at generally 90° to the fluid distributing portion. 
     The chamber of the humidifier can also be contain a packing material, such as, for example, metal chips, plastic chips, or any other suitable random or structured packing material. The packing material can fill two thirds of the chamber of the housing. 
     Further, at least one port can be provided to connect the fluid distributing portion to an external fluid source. At least one fluid distributing port can also be provided to distribute the fluid to the chamber, and a at least one fluid passage to connect the ports to the fluid distributing ports. The fluid distributing ports can be provided with fluid spraying nozzles. A fluid level sensor to monitor the fluid level in the chamber can also be provided. 
     The housing is open at least one end and the fluid distributing portion is disposed within the open end of the housing. In one embodiment the housing is disposed so that the at least one open end faces upwardly. In another embodiment the housing is disposed so that at least one open end faces a side thereof. In yet a further embodiment the housing is disposed so that one open end faces one side thereof and a another open end faces an opposed side thereof. For each of these embodiments the water distributing portion can be disposed over the open end of the housing. 
     Further the housing and the fluid distributing portion can be generally rectangular in shape. Similarly the chamber can be generally rectangular in shape. The gas inlet and the gas outlet can be provided at opposite ends of the housing. 
     For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made to the accompanying drawings, which show, by way of example, preferred embodiments of the present invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view illustrating the first embodiment of the humidifier in accordance with the present invention; 
     FIG. 2 is a perspective view illustrating the housing of the humidifier in the first embodiment in accordance with the present invention; 
     FIG. 3 is a perspective longitudinal section view illustrating the housing of the humidifier in the first embodiment in accordance with the present invention; 
     FIG. 4 is a perspective view illustrating the water distributing portion of the humidifier in the first embodiment in accordance with the present invention; 
     FIG. 5 is a longitudinal section view illustrating the water distributing portion of the humidifier in the first embodiment in accordance with the present invention; 
     FIG. 6 is a plan view illustrating the water distributing portion of the humidifier in the first embodiment in accordance with the present invention; 
     FIG. 7 is a perspective view illustrating the first embodiment of the humidifier in accordance with the present invention, filled with packing materials; 
     FIG. 8 is a longitudinal section view illustrating a second embodiment of the humidifier in accordance with the present invention; 
     FIG. 9 is a longitudinal section view illustrating a third embodiment of the humidifier in accordance with the present invention; 
     FIG. 10 a  shows a schematic view of one example of conventional humidifiers; 
     FIG. 10 b  shows a schematic view of another example of conventional humidifiers. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIGS. 10 a  and  10   b  show two types of conventional humidifiers. In particular, FIG. 10 a  shows a humidifier that does not use a packing material, while FIG. 10 b  shows a humidifier that uses a packing material. 
     Referring to FIG. 10 a , the humidifier  10  has a generally hollow cylindrical body  9  and a plurality of water injection nozzles  11  for injecting water into the hollow cylindrical body  9 . The water injection nozzles  11  are typically provided on the side wall  8  of the hollow cylindrical body  9 . Gas enters the humidifier through a gas inlet  12  provided at one end  7  of the hollow cylindrical body  9  and flows along the axial direction of the hollow cylindrical body  9  to exit through a gas outlet  13  provided at the opposite end  6 . As the gas flows through the hollow cylindrical body  9 , water is injected into the hollow  5  of the body  9  through the plurality of nozzles  11 , humidifying the gas. The humidified gas then leaves the hollow cylindrical body  9  through the gas outlet  13  provided on the end wall  6 . 
     FIG. 10 b  shows another design of a conventional humidifier  20  that uses a suitable packing material  25  to increase the contact area between the gas and the water. Humidifier  20  has a generally hollow cylindrical body  19  that is disposed in a substantially vertical position. The gas enters the hollow cylindrical body  19  from a gas inlet  22  provided on a bottom wall  18  of the hollow cylindrical body  19 , and is forced to flow upwardly along the axial direction of the hollow cylindrical body  19  by a blower or fan (not illustrated). A water inlet  17  is provided on a top wall  16  of the hollow cylindrical body  19  to dispense water to a water distribution plate  21  that is disposed within the hollow cylindrical body  19  generally parallel to and near the top wall  16 . A plurality of holes  24  are provided in the water distribution plate  21  so that water coming from the water inlet  17  can drip down through the holes  24  to humidify the gas flowing upwardly through the hollow cylindrical body  19 . Packing material  25  can be packed between the water distribution plate  21  and the bottom wall  18  to increase the contact area between the gas and the water. 
     FIG. 1 shows a first embodiment of the humidifier  500  of the present invention. Hereinafter, the present invention will be described using humidifying air with water as an example. It should be appreciated, however, that the present invention can also be used to humidify other gases or fluids and to exchange heat. 
     The humidifier  500  generally consists of a housing  100  and a water distributing portion  300 . As shown in FIG. 2, the housing  100  of the humidifier  500  is generally rectangular in shape. The housing  100  has four side walls, namely a first pair of opposite side walls  120   a ,  120   b  and a second pair of opposite side wall  140   a ,  140   b , and a bottom wall  160 , defining an inner space or chamber  102  open along the top, as at  104 . As shown in FIG. 2, in this embodiment, the side walls  140   a ,  140   b  have a greater length than the side walls  120   a  and  120   b.    
     One of the side walls  140   a  is provided with four connector portions, specifically, an air inlet  110 , an air outlet  111 , a water outlet  114 , and a connector  113  for a water level sensor (not illustrated). Each of the connector portions is in fluid communication with chamber  102  of the housing  100  so that the air and water can flow through the respective connector portions into or out of the chamber  102  of the housing  100 . 
     A flange portion  180  is provided around the open top  104  of the housing  100 . The flange portion  180  extends substantially perpendicular from the side walls  120   a ,  120   b  and  140   a ,  140   b  to form a planar surface  181  to receive the water distributing portion  300 . A plurality of through holes  190  are spaced evenly on the planar surface  181  to receive a plurality of bolts (not shown) used to attach the water distributing portion  300  onto the flange portion  180  of the housing  100 . 
     Referring to FIG. 3, a plurality of spaced baffle plates  200   a ,  200   b  are provided in the chamber  102  of the housing  100 . Each of the baffle plates  200   a ,  200   b  is provided with a top edge  204  and a bottom edge  202 . The baffle plates  200   a ,  200   b  have substantially the same width as that of the side walls  120   a ,  120   b , that is to say, for the embodiment disclosed, the baffle plates  200   a ,  200   b  extend from one side wall  140   a  to the other side wall  140   b  and are substantially parallel to the side walls  120   a  and  120   b . Moreover, the baffle plates  200   a ,  200   b  extend nearly the height of the housing  100 , and are spaced from each other along the length of the housing  100 . The extent of the baffle plates  200   a ,  200   b  with the chamber  102  is sufficient to define gas flow paths  201  adjacent the respective baffle plates  200   a ,  200   b . It is to be understood that the baffle plates  200   a ,  200   b  can be of various shapes and it is not necessary that the baffle plates  200   a ,  200   b  be similar in shape and dimension to each other. For the embodiment disclosed, the baffle plates  200   a ,  200   b  have generally the same shape and dimension. 
     Each of the baffle plates  200   a ,  200   b  is provided with an opening  203  to allow gas to flow between adjacent flow paths  201 . For the embodiment disclosed, the opening is defined by spacing an end of the baffle plates  200   a ,  200   b  from at least one of the fluid distributing portions  300  and inner walls of the chamber  102 , as will hereinafter be described. Moreover, the opening of a given baffle plate is at an end of the baffle plate that is opposed to the end of where an opening of an adjacent baffle plate is provided. 
     Preferably, the baffle plates  200   a ,  200   b  are positioned within the chamber  102  of the housing  100  so that adjacent baffle plates are offset with respect to the height of the housing. Baffle plates  200   a  are positioned with one end  202  adjacent the bottom wall  160  of the housing  100  and with the other end  204  spaced from the planar surface  181  of the flange portion  180 . This defines the opening  203  for baffle plates  200   a  between end  204  and the planar surface  181  of the flange portion  180 . Baffle plates  200   b  are positioned with the end  204  adjacent the planar surface  181  and with the other end  202  spaced from the bottom wall  160  of the housing  100 . This defines the opening  203  for baffle plates  200   b  between end  202  and the bottom well  160  of the housing  100 . By so alternating the positioning of the baffles plates  200   a ,  200   b  along the length of the housing  100 , a tortuous gas flowing path is defined from the air inlet  110  to the air outlet  111 . For the embodiment illustrated the bottom end  202  of each baffle plate  200   a  that is connected to the bottom wall  160  is provided with an aperture  210  to permit water to flow through as will hereinafter be described. 
     Now referring to FIGS. 4-6, the water distributing portion  300  is shown generally in the form of a rectangular plate having a certain thickness. The water distributing portion  300  has at least one internal fluid passage  320 . For the embodiment illustrated, the water distributing portion  300  has two internal passages  320  extending parallel to each other and to the length of the water distribution portion  300 . More fluid passages can be provided where necessary, for example, where the housing  100  has a greater width. 
     Ports  310  to the internal passages  320  are provided on one end wall  360  of the water distribution portion  300 . Similarly, two ports  380  to the internal passages  320  may be provided on the opposite end wall  370  of the water distribution portion  300 . This provides mounting flexibility so that the water distribution portion  300  can be connected to external ducts or hoses at either or both ends. 
     The facing  330  of the water distribution portion  300  that is in contact with the planar surface  181  of the flange portion  180  of the housing  100  is provided with a plurality of through holes  340  and a plurality of water distributing ports  350 . The through holes  340  are arranged to correspond with the through holes  190  on the flange portion  180  so that fastening means, such us bolts (not Illustrated), can be inserted In the through holes to attach the water distributing portion  300  to the flange portion  180  of the housing  100 . Sealing means (not illustrated), such as gaskets, can be provided between the wall  330  and the flange portion  180  to prevent leakage of water, gas or a mixture thereof. Each of the ports  310  or  380  is in fluid communication with its corresponding internal fluid passage  320 . Moreover, the water distributing ports  350  are provided In the wall  330  to be in fluid communication with the internal fluid passages  320 . In the embodiment illustrated, a simple arrangement is shown. Specifically, each internal fluid passage  320  is straight and the water distributing ports  350  are arranged along lines corresponding to the Internal fluid passages  320 , as shown in FIG.  4  and FIG.  6 . More preferably, water distributing ports  350  are threaded holes and water spraying nozzles  600  (illustrated in FIG. 5) are mounted in the water distributing ports  350  by means of a suitable threaded connection. The water spraying nozzles  600  spray water mist into the inner space  102  of the housing  100 . 
     For the embodiment illustrated, the humidifier  500  is disposed in a substantially vertical position during operation. The water distributing portion  300  is mounted onto the open end of the housing  100 , defining the inner surface or chamber  102  inside the housing as best seen in FIG.  7 . The air inlet  110  and outlet  111  are connected to an air circulation loop (not shown). As shown in FIGS. 2 and 3, the air inlet  110  is provided on a side wall  140   a  at a position near the lower of the side wall  140   a  and near the side wall  120   a . The air outlet  111  is provided on the same side wall  140   a  at a position near the upper of the side wall  140   a  and near the opposite side wall  120   b . For the embodiment illustrated, the air inlet  110  and the air outlet  111  are arranged on side wall  140   a  substantially diagonal to each other. As previously disclosed the baffle plates  200   a ,  200   b  are arranged so that a baffle plate  200   a  is positioned near the air inlet  110  and a baffle plate  200   b  is positioned near the air outlet  111 . This arrangement provides a long air flow path in the chamber  102  of the housing  110 . 
     Air enters the chamber  102  through the air inlet  110  it flows upwardly along the height of the housing  100  between the first baffle plate  200   a  and the side wall  120 . The air then flows through the opening  203  defined between the upper end  204  of the first baffle plate  200   a  and the water distribution portion  300  then downwardly along the height of the housing  100  between the first baffle plate  200   a  and the first baffle plate  200   b . The air flows repeatedly in this manner between the respective baffle plates  200   a  and  200   b  until it exits the humidifier  500  through the air outlet  111 . The arrangement of the air inlet  110 , outlet  111  and the baffle plates  200   a ,  200   b  provides a tortuous flowing path for the air allowing the air to sufficiently contact the humidifying water. By providing a tortuous humidifying path the humidifier of the present invention can be compact. 
     The humidifying water is supplied from the ports  310  or  380  from any readily available sources and it can be pressurized or heated if desired. The humidifying water is sprayed from the nozzles  600  provided on the water distributing ports  350  in the form of mist to mix with the air flowing along the flow path described above. As water is continuously falling from the water distribution portion  300  into the housing  100 , it can accumulate at the bottom portion of the chamber to a certain level. A plurality of apertures  210  are provided at the bottom ends  202  of the baffles plates  200   a  to allow water to flow across the bottom wall  160  of the housing  100  to the water outlet  114  through which it can be drained. 
     It is desirable to maintain the water height within the chamber  102  of the housing  100  at a certain level, for example, half of the height of the chamber  102 . Therefore, a water level sensor  400  can be mounted onto the connector port  113  to monitor the water level in the chamber  102 . Once the water level is below the level of the sensor, the sensor sends signals to a processor (not shown), which, in turn, adjusts the humidifying water flow. 
     A packing material  390  can be provided in chamber  102  between adjacent baffles plates, as can be best seen in FIG.  7 . The packing material  390  can be metal chips, plastic chips or other suitable random or structured packing material. Since the packing material  390  has small internal passages, gas and water can flow through the packing material. Further, since the packing material  390  has a high surface to volume ratio, the contact area between the gas and the water is increased. The packing material may fill in, for example, half or ⅔ of the total volume of the chamber  102 . 
     Now referring to FIG. 8, a second embodiment of the humidifier of the present invention is shown. Similar components as in the first embodiment are indicated with same reference numbers. In the second embodiment, the housing  100  is rotated so that the open end  172  is provided on one side thereof. As in the first embodiment the water distributing portion  300  closes the open end  172 . In this embodiment the baffle plates  200   a  and  200   b  are spaced from each other in the vertical direction. A plurality of water spraying nozzles  600  can be provided on the water distributing portion  300  to spray water into the chamber  102 . For this embodiment the gas inlet  110 ′ and a gas outlet  111 ′ are provided respectively on the bottom wall  170  and the top wall  171  of the housing  100 . It can be appreciated, however, that the gas inlet and outlet can be switched according to the type of gas the humidifier  500  is working with. For example, when the humidifier is used to humidify light gases, such as hydrogen, the arrangement of FIG. 8 is preferred. However, when working with heavy gases it might be desirable to use the gas outlet  111 ′ as the inlet for the gas. The gas inlet and outlet can also be provided as in the first embodiment, if desired. 
     A third embodiment of the humidifier  500  is shown in FIG.  9 . This embodiment is similar to the embodiment disclosed in FIG. 8, except the housing  100  of the humidifier  500  is open as at  172  and  173  and has two water distributing portions  300   a  and  300   b , respectively, to close the open ends  172  and  173  of the housing  100 . A plurality of water spraying nozzles  600  can be provided on the water distributing portions  300   a  and  300   b  to spray water into the chamber  102 . The gas inlet  110 ″ and the gas outlet  111 ″ can be provided as described for the embodiment illustrated in FIG.  8 . 
     For both the second and third embodiments, a packing material can be provided in the chamber  102  of the housing  100  to increase the contact area between the gas and the water. 
     It is to be understood that the arrangement of the air inlet  110  and the air outlet  111  and the arrangement of the baffle plates  200   a ,  200   b  can be different from that disclosed in the preferred embodiments disclosed herein. For example, the air inlet  110  or the air outlet  111  can be provided on the side walls  120   a  or  120   b . Further, the air inlet and the air outlet do not necessarily need to be provided on the same side wall. Moreover, although the present invention is described using a rectangular shaped housing for the humidifier as an example, the humidifier and the housing shape need not be this shape. 
     It should also be appreciated that the present invention is not limited to the embodiment disclosed herein. It can be anticipated that those having ordinary skills in the art can make various modification to the embodiments disclosed herein after learning the teaching of the present invention. For example, the number and arrangement of components in the system might be different, and different elements might be used to achieve the same specific function. However, these modifications should be considered to fall within the scope of the invention as defined in the following claims.