Abstract:
A monolithic hygroscopic material shaped to facilitate a circulation flow of ambient air. The hygroscopic material may be used to remove various compounds from an ambient gas and may be reactivated to restore its drying capacity. The tendency of the material to seek equilibrium may be utilized to achieve dehumidification or humidification.

Description:
This application is a continuation of Ser. No. 09/157,208, filed Sep. 18, 1998, now U.S. Pat. No. 6,280,504. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to dehumidifiers. More particularly, the present invention relates to a hygroscopic material having a shape and surface area orientation which facilitates circulation and drying of a working gas. 
     Dehumidifiers are used to dry working gases, such as water vapor in air. Typical desiccant dehumidifying machines blow the air or working gas across a desiccant material to remove the vapor from the working gas. These types of machines require a power source and typically utilize moving parts to dry the working space. In addition, the desiccant is typically contained or packaged within the machine and the vapor rich air is mechanically passed across the desiccant. In addition to requiring active intervention to turn the machine ON and OFF, such devices are limited by their power needs, the breakdown of the moving mechanical components, and a somewhat inefficient use of the desiccant material. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention provides a shaped monolithic hygroscopic material which moves air through a “chimney effect” or air density differences in and around the material. The present invention thus provides a passive dehumidifier which allows direct contact with the gas being dried without the need for an outside power source, moving parts, or packaging of a desiccant material. Alternatively, the tendency of the material to seek equilibrium with the working gas may also be utilized to achieve humidification. 
     The present invention comprises a hygroscopic material having at least one passageway or channel therethrough. The material is shaped to provide a surface area to facilitate gas flow, and drying of an ambient gas by creating a chimney effect which facilitates mixing of the gas. This causes the heavier water vapor or other compound containing gas to contact adsorbent material adjacent to the passageway or channel, adsorb at least some of the compound, and cause the lighter gas to exit the passageway or channel. The dehumidifier may have various shapes and sizes and can be reactivated to restore its drying capacity. When utilized as a humidifier, the material desorbs or adds the constituent (such as water vapor) to the gas and a downdraft rather than a chimney effect is achieved. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view of one embodiment of the present invention illustrating flow of air or other gas therethrough. 
     FIG. 2 is a phantom view of FIG.  1 . 
     FIG. 3 is a cross-sectional view taken along section lines  3 — 3  of FIG.  2 . 
     FIG. 4 is a perspective view of an alternate embodiment of the present invention illustrating air or other gas flow therethrough. 
     FIG. 5 is a top view of FIG.  4 . 
     FIG. 6 is a cross sectional view taken along section lines  6 — 6  of FIG.  4 . 
     FIG. 7 is a perspective view of a further alternate embodiment of the present invention illustrating air or other gas flow therethrough. 
     FIG. 8 is a top view of FIG.  7 . 
     FIG. 9 is a cross sectional view taken along section lines  9 — 9  of FIG.  7 . 
     FIG. 10 is a side view of an embodiment of the present invention utilized as a humidifier and illustrating alternate flow of air or other gas therethrough. 
     FIG. 11 is a graph illustrating the data reflected in Table 1. 
     FIG. 12 is a graph illustrating the data reflected in Table 2. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1, FIG.  2  and FIG. 3, an embodiment of the present invention is identified by the number  14 . For purposes of the present description, it will be described in connection with its usage as a dehumidifier  14 . The dehumidifier  14  comprises a shaped, monolithic hygroscopic material  16 . The material  16  has a plurality of external surface areas which include a plurality of generally square external surfaces  18  and a plurality of generally triangular external surfaces  20 . The material  16  has a generally polyhedron or faceted shape. 
     As further illustrated in FIG. 2, the material  16  has a plurality of channels or passageways  22  therethrough. Each passageway  22  has an inlet port and an outlet port, identified generally by the number  24 . Depending upon the orientation of the material  16 , any port  24  may function as an inlet port or outlet port. As illustrated in FIG. 3, each passageway  22  has an internal surface  26 . Each passageway  22  is generally cylindrical, passes from one side of material  16  to an opposite side, and has a plurality of other passages  22  in fluid communication with and generally perpendicular thereto. 
     Referring again to FIG. 1, the usage and operation of the dehumidifier  14  will be described in greater detail. The dehumidifier  14  may be placed in any environment having water vapor or other compound or constituent (for which dehumidifier  14  has an affinity) within a working gas, such as air. When the heavier, denser compound/vapor laden gas (dotted arrows) enters an inlet port  24  it is dried by the surface area  26  of the adsorbent material  16  within the corresponding passageway  22 . The lighter, drier air (clear arrows) thereafter exits through a port  24 . As the dry air rises, a circulation or “chimney” effect is created within the working environment, as illustrated by the arrows in FIG.  1 . That is, the lighter, drier air rises from the dehumidifier  14  and the heavier, vapor laden air is circulated to enter the dehumidifier  14  (passages  22 ) so that the water vapor or other constituent of the gas is adsorbed (or absorbed) by material  16 . Surfaces  18  and  20  may also provide some adsorption (or absorption) of the gaseous constituent. 
     Testing of the embodiment of FIG. 1 yielded the results reflected in Table 1, as graphically depicted in FIG.  11 . In the test, a dehumidifier  14  having a mass of approximately 10 grams (natural zeolite) was activated (dried) in a microwave oven and placed in a sealed, one liter glass beaker with a probe for measuring temperature (degrees Fahrenheit), relative humidity (% Rh), dewpoint (degrees Fahrenheit), and absolute humidity (grains per pound). Readings of the probe were taken every thirty seconds. As evidenced by the data collected, the dehumidifier  14  rapidly and efficiently dried the air in the beaker. 
     
       
         
               
             
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Dehumidification Data, 1 liter air volume, 30 sec interval 
               
             
          
           
               
                   
                 Relative 
                   
                 Dewpoint 
                 Absolute 
                   
               
               
                   
                 Humidity 
                 Temp 
                 Temp. 
                 Humidity 
                 Time 
               
               
                   
                 Rh 
                 T 
                 Td 
                 x 
                 t 
               
               
                   
                 A 
                 B 
                 C 
                 D 
                 E 
               
               
                   
                   
               
             
          
           
               
                   
                 1 
                 57.1 
                 75.5 
                 59.4 
                 75.4 
                 0 
               
               
                   
                 2 
                 30.2 
                 75.5 
                 40.6 
                 36 
                 0.5 
               
               
                   
                 3 
                 23.8 
                 75.5 
                 35.4 
                 29.6 
                 1 
               
               
                   
                 4 
                 15.7 
                 75.6 
                 25.7 
                 19.6 
                 1.5 
               
               
                   
                 5 
                 11.8 
                 75.6 
                 18.8 
                 15.1 
                 2 
               
               
                   
                 6 
                 8.9 
                 75.7 
                 12.4 
                 11.6 
                 2.5 
               
               
                   
                 7 
                 7.1 
                 75.7 
                 7.5 
                 9.15 
                 3 
               
               
                   
                 8 
                 5.8 
                 75.7 
                 3.1 
                 7.4 
                 3.5 
               
               
                   
                 9 
                 4.8 
                 75.8 
                 −0.9 
                 6.16 
                 4 
               
               
                   
                 10 
                 4.1 
                 75.8 
                 −4.4 
                 5.16 
                 4.5 
               
               
                   
                 11 
                 3.5 
                 75.8 
                 −7.3 
                 4.55 
                 5 
               
               
                   
                 12 
                 3.1 
                 75.8 
                 −9.9 
                 4 
                 5.5 
               
               
                   
                 13 
                 2.7 
                 75.8 
                 −12.4 
                 3.56 
                 6 
               
               
                   
                 14 
                 2.4 
                 75.9 
                 −14.6 
                 3.14 
                 6.5 
               
               
                   
                 15 
                 2.2 
                 75.9 
                 −16.3 
                 3.09 
                 7 
               
               
                   
                 16 
                 2 
                 75.9 
                 −18.1 
                 2.68 
                 7.5 
               
               
                   
                 17 
                 1.8 
                 75.9 
                 −19.9 
                 2.4 
                 8 
               
               
                   
                 18 
                 1.7 
                 75.9 
                 −21 
                 2.26 
                 8.5 
               
               
                   
                 19 
                 1.6 
                 75.9 
                 −22.4 
                 2.1 
                 9 
               
               
                   
                 20 
                 1.5 
                 75.9 
                 −23.7 
                 1.98 
                 9.5 
               
               
                   
                 21 
                 1.4 
                 76 
                 −24.6 
                 1.88 
                 10 
               
               
                   
                 22 
                 1.3 
                 76 
                 −25.7 
                 1.77 
                 10.5 
               
               
                   
                 23 
                 1.3 
                 76 
                 −26.6 
                 1.67 
                 11 
               
               
                   
                 24 
                 1.2 
                 76 
                 −27.6 
                 1.59 
                 11.5 
               
               
                   
                 25 
                 1.1 
                 76 
                 −28.6 
                 1.5 
                 12 
               
               
                   
                 26 
                 1.1 
                 76 
                 −29.4 
                 1.45 
                 12.5 
               
               
                   
                 27 
                 1 
                 76.1 
                 −30.3 
                 1.39 
                 13 
               
               
                   
                 28 
                 1 
                 76.1 
                 −31 
                 1.31 
                 13.5 
               
               
                   
                 29 
                 1 
                 76.1 
                 −31.6 
                 1.31 
                 14 
               
               
                   
                 30 
                 0.9 
                 76.1 
                 −32.5 
                 1.23 
                 14.5 
               
               
                   
                 31 
                 0.9 
                 76.1 
                 −33.2 
                 1.16 
                 15 
               
               
                   
                 32 
                 0.9 
                 76.1 
                 −33.8 
                 1.14 
                 15.5 
               
               
                   
                 33 
                 0.8 
                 76.1 
                 −34.3 
                 1.08 
                 16 
               
               
                   
                 34 
                 0.8 
                 76.1 
                 −35 
                 1.06 
                 16.5 
               
               
                   
                 35 
                 0.8 
                 76.1 
                 −35.4 
                 1.04 
                 17 
               
               
                   
                 36 
                 0.8 
                 76.1 
                 −36 
                 0.99 
                 17.5 
               
               
                   
                 37 
                 0.7 
                 76.1 
                 −36.5 
                 0.98 
                 18 
               
               
                   
                 38 
                 0.7 
                 76.1 
                 −37 
                 0.94 
                 18.5 
               
               
                   
                 39 
                 0.7 
                 76.1 
                 −37.6 
                 0.91 
                 19 
               
               
                   
                 40 
                 0.7 
                 76.1 
                 −38 
                 0.88 
                 19.5 
               
               
                   
                 41 
                 0.6 
                 76.1 
                 −38.6 
                 0.86 
                 20 
               
               
                   
                 42 
                 0.6 
                 76.1 
                 −39 
                 0.83 
                 20.5 
               
               
                   
                 43 
                 0.6 
                 76.1 
                 −39.7 
                 0.81 
                 21 
               
               
                   
                 44 
                 0.6 
                 76.1 
                 −40 
                 0.77 
                 21.5 
               
               
                   
                 45 
                 0.6 
                 76.1 
                 −40.5 
                 0.76 
                 22 
               
               
                   
                 46 
                 0.6 
                 76.1 
                 −41 
                 0.74 
                 22.5 
               
               
                   
                 47 
                 0.5 
                 76.1 
                 −41.4 
                 0.72 
                 23 
               
               
                   
                 48 
                 0.5 
                 76.1 
                 −41.8 
                 0.71 
                 23.5 
               
               
                   
                 49 
                 0.5 
                 76.1 
                 −42 
                 0.69 
                 24 
               
               
                   
                 50 
                 0.5 
                 76.1 
                 −42.4 
                 0.67 
                 24.5 
               
               
                   
                 51 
                 0.5 
                 76.1 
                 −43 
                 0.66 
                 25 
               
               
                   
                 52 
                 0.5 
                 76.1 
                 −43.3 
                 0.65 
                 25.5 
               
               
                   
                 53 
                 0.5 
                 76.1 
                 −43.7 
                 0.63 
                 26 
               
               
                   
                 54 
                 0.5 
                 76.1 
                 −44.2 
                 0.61 
                 26.5 
               
               
                   
                 55 
                 0.5 
                 76.1 
                 −44.6 
                 0.6 
                 27 
               
               
                   
                 56 
                 0.4 
                 76.1 
                 −45 
                 0.59 
                 27.5 
               
               
                   
                 57 
                 0.4 
                 76.2 
                 −45.3 
                 0.58 
                 28 
               
               
                   
                 58 
                 0.4 
                 76.2 
                 −45.8 
                 0.56 
                 28.5 
               
               
                   
                 59 
                 0.4 
                 76.2 
                 −46 
                 0.55 
                 29 
               
               
                   
                 60 
                 0.4 
                 76.2 
                 −46.2 
                 0.54 
                 29.5 
               
               
                   
                 61 
                 0.4 
                 76.2 
                 −46.8 
                 0.53 
                 30 
               
               
                   
                 62 
                 0.4 
                 76.2 
                 −47 
                 0.51 
                 30.5 
               
               
                   
                 63 
                 0.4 
                 76.2 
                 −47.3 
                 0.5 
                 31 
               
               
                   
                 64 
                 0.4 
                 76.2 
                 −47.7 
                 0.5 
                 31.5 
               
               
                   
                 65 
                 0.4 
                 76.2 
                 −48 
                 0.49 
                 32 
               
               
                   
                 66 
                 0.4 
                 76.2 
                 −48.4 
                 0.48 
                 32.5 
               
               
                   
                 67 
                 0.3 
                 76.2 
                 −48.7 
                 0.47 
                 33 
               
               
                   
                 68 
                 0.3 
                 76.2 
                 −49 
                 0.45 
                 33.5 
               
               
                   
                 69 
                 0.3 
                 76.2 
                 −49.4 
                 0.45 
                 34 
               
               
                   
                 70 
                 0.3 
                 76.2 
                 −49.9 
                 0.43 
                 34.5 
               
               
                   
                 71 
                 0.3 
                 76.2 
                 −50 
                 0.42 
                 35 
               
               
                   
                 72 
                 0.3 
                 76.2 
                 −50.8 
                 0.41 
                 35.5 
               
               
                   
                 73 
                 0.3 
                 76.2 
                 −51 
                 0.4 
                 36 
               
               
                   
                 74 
                 0.3 
                 76.2 
                 −51.6 
                 0.39 
                 36.5 
               
               
                   
                 75 
                 0.3 
                 76.2 
                 −51.8 
                 0.39 
                 37 
               
               
                   
                 76 
               
               
                   
                 77 
                 0.2 
                 76.2 
                 −60.7 
                 0.22 
                 61.5 
               
               
                   
                 78 
                 0.2 
                 76.2 
                 −61 
                 0.21 
                 89.5 
               
               
                   
                   
               
             
          
         
       
     
     Referring to FIG. 4, FIG.  5  and FIG. 6, an alternate embodiment of the present invention is identified by the number  30 . For purposes of the present description, it will be described in connection with its usage as a dehumidifier  30 . The dehumidifier  30  comprises a shaped, monolithic hygroscopic material  32 . The material  32  has a plurality of generally rectangular columns  34  which define a plurality of external channels  36  therein. Each channel  36  has internal surfaces  38 . Channels  36  extend the length L, width W, and depth D of dehumidifier  30  and the length L is generally twice the width W and twice the depth D with the width W and depth D being approximately equal. The material  32  has a generally columnar shape, a plurality of generally square external surfaces  40  and a plurality of generally rectangular external surfaces  42 . 
     Referring again to FIG.  5  and FIG. 6, the material  32  further comprises a cylindrical internal passageway  44  therethrough. Passageway  44  has an inlet port  45  on a first lengthwise end of dehumidifier  30  and an outlet port  46  on a second, opposite lengthwise end of dehumidifier  30 . Passageway  44  extends from channel  36  on one lengthwise end of dehumidifier  30  to channel  36  on the opposite lengthwise end and has an internal surface  48 . As may be readily understood, ports  44  and  45  may each serve as an inlet port and an outlet port, depending upon the orientation of the dehumidifier  30 . 
     Referring again to FIG. 4, the usage and operation of the dehumidifier  30  will be described in greater detail. The dehumidifier  30  may be placed in any environment having water vapor or other compound or constituent (for which dehumidifier  30  has an affinity) within a working gas, such as air. When the heavier, denser compound/vapor laden gas (dotted arrows) enters the channels  36  it is dried by the surface area  38  of the adsorbent material  32  within the corresponding channel  36 . The lighter, drier air (clear arrows) thereafter exits the respective channel  36 . Likewise, heavier, denser compound/vapor laden gas (dotted arrows) enters inlet port  45  and is dried by the surface area  48  of the adsorbent material  32  within passageway  44 . The lighter, drier air (clear arrows) thereafter exits through exit port  46 . As the dry air from channels  36  and passage  44  rises, a circulation or “chimney” effect is created within the working environment, as illustrated by the arrows in FIG.  4 . That is, the lighter, drier air rises from the dehumidifier  30  and the heavier, vapor laden air is circulated to enter the dehumidifier  30  (channels  36  and passage  44 ) so that the water vapor or other constituent of the gas is adsorbed (or absorbed) by material  32 . Surfaces  40  and  42  may also provide some adsorption (or absorption) of the gaseous constituent. 
     Testing of the embodiment of FIG. 4 yielded the results reflected in Table 2, as graphically depicted in FIG.  12 . In the test, a dehumidifier  30  having a mass of approximately 40 grams (natural zeolite) was activated (dried) in a microwave oven and placed in a sealed one liter glass beaker with a probe for measuring temperature (degrees Fahrenheit), relative humidity (% Rh), dewpoint (degrees Fahrenheit), and absolute humidity (grains per pound). Readings of the probe were taken every thirty seconds. As evidenced by the data collected, the dehumidifier  30  rapidly and efficiently dried the air in the beaker. 
     
       
         
               
             
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 Dehumidification Data, 1 liter air volume, 30 sec interval 
               
             
          
           
               
                   
                 Relative 
                   
                 Dewpoint 
                 Absolute 
                   
               
               
                   
                 Humidity 
                 Temp 
                 Temp. 
                 Humidity 
                 Time 
               
               
                   
                 Rh 
                 T 
                 Td 
                 X 
                 t 
               
               
                   
                 A 
                 B 
                 C 
                 D 
                 E 
               
               
                   
                   
               
             
          
           
               
                   
                 1 
                 51.1 
                 68.2 
                 49.4 
                 52.2 
                 0 
               
               
                   
                 2 
                 38.7 
                 68.5 
                 41.8 
                 38.5 
                 0.5 
               
               
                   
                 3 
                 33.7 
                 68.6 
                 38.5 
                 33.9 
                 1 
               
               
                   
                 4 
                 28.3 
                 68.8 
                 34.4 
                 28.9 
                 1.5 
               
               
                   
                 5 
                 23.3 
                 68.8 
                 29.8 
                 24 
                 2 
               
               
                   
                 6 
                 20.3 
                 68.9 
                 26.3 
                 20.7 
                 2.5 
               
               
                   
                 7 
                 17.4 
                 69 
                 22.8 
                 17.9 
                 3 
               
               
                   
                 8 
                 15.7 
                 69.1 
                 20.5 
                 16.2 
                 3.5 
               
               
                   
                 9 
                 13.6 
                 69.2 
                 17.3 
                 14.2 
                 4 
               
               
                   
                 10 
                 12.4 
                 69.3 
                 15.1 
                 12.9 
                 4.5 
               
               
                   
                 11 
                 11.3 
                 69.3 
                 13.3 
                 11.9 
                 5 
               
               
                   
                 12 
                 10.5 
                 69.4 
                 11.5 
                 11 
                 5.5 
               
               
                   
                 13 
                 9.7 
                 69.5 
                 9.8 
                 10.2 
                 6 
               
               
                   
                 14 
                 8.9 
                 69.6 
                 8.3 
                 9.51 
                 6.5 
               
               
                   
                 15 
                 8.4 
                 69.7 
                 6.6 
                 8.82 
                 7 
               
               
                   
                 16 
                 7.9 
                 69.7 
                 5.5 
                 8.4 
                 7.5 
               
               
                   
                 17 
                 7.4 
                 69.8 
                 4.3 
                 7.91 
                 8 
               
               
                   
                 18 
                 7 
                 69.9 
                 3 
                 7.48 
                 8.5 
               
               
                   
                 19 
                 6.6 
                 69.9 
                 1.9 
                 7.09 
                 9 
               
               
                   
                 20 
                 6.3 
                 70 
                 1 
                 6.76 
                 9.5 
               
               
                   
                 21 
                 6 
                 70.1 
                 0 
                 6.48 
                 10 
               
               
                   
                 22 
                 5.8 
                 70.2 
                 −0.9 
                 6.2 
                 10.5 
               
               
                   
                 23 
                 5.5 
                 70.2 
                 −1.9 
                 5.93 
                 11 
               
               
                   
                 24 
                 5.2 
                 70.3 
                 −2.8 
                 5.67 
                 11.5 
               
               
                   
                 25 
                 5 
                 70.4 
                 −3.6 
                 5.45 
                 12 
               
               
                   
                 26 
                 4.8 
                 70.4 
                 −4.4 
                 5.26 
                 12.5 
               
               
                   
                 27 
                 4.7 
                 70.5 
                 −5.1 
                 5.08 
                 13 
               
               
                   
                 28 
                 4.5 
                 70.5 
                 −5.8 
                 4.89 
                 13.5 
               
               
                   
                 29 
                 4.3 
                 70.5 
                 −6.5 
                 4.73 
                 14 
               
               
                   
                 30 
                 4.2 
                 70.6 
                 −7.2 
                 4.57 
                 14.5 
               
               
                   
                 31 
                 4 
                 70.6 
                 −7.9 
                 4.43 
                 15 
               
               
                   
                 32 
                 3.2 
                 70.5 
                 −13 
                 3.43 
                 20 
               
               
                   
                 33 
                 2.7 
                 70 
                 −16.1 
                 2.93 
                 25.5 
               
               
                   
                 34 
                 2.5 
                 70.1 
                 −18.1 
                 2.66 
                 30.5 
               
               
                   
                 35 
                 2.3 
                 70.6 
                 −19.4 
                 2.49 
                 40.5 
               
               
                   
                 36 
                 1.3 
                 70.3 
                 −29.6 
                 1.42 
                 65.5 
               
               
                   
                   
               
             
          
         
       
     
     Referring to FIG. 7, FIG.  8  and FIG. 9, another embodiment of the present invention is identified by the number 50. For purposes of the present description, it will be described in connection with its usage as a dehumidifier  50 . The dehumidifier  50  comprises a shaped, monolithic hygroscopic material  52 . The material  52  has a plurality of external surface areas which include a plurality of generally square external surfaces  54  and a plurality of generally rectangular surface areas  56 . 
     As further illustrated in FIG.  7  and FIG. 8, the material  52  has a plurality of channels  58  therein. Each channel  58  has internal surfaces  60 . Channels  58  extend the length L, width W, and depth D of dehumidifier  50  with the length L, width W and depth D being approximately equal so as to form a generally cubed shape. 
     Referring again to FIG.  8  and FIG. 9, the material  52  has a plurality of passageways  62  therethrough. Each passageway  62  has an inlet port and an outlet port, identified by the number  64 . Depending upon the orientation of the material  52 , any port  64  may function as an inlet port or outlet port. Each passageway  62  has an internal surface  66 . Each passageway  62  is generally cylindrical, passes from one side of material  52  to an opposite side, and it has a plurality of other passages  62  in fluid communication with and generally perpendicular thereto. 
     Referring again to FIG. 7, the usage and operation of the dehumidifier  50  will be described in greater detail. The dehumidifier  50  may be placed in any environment having water vapor or other compound or constituent (for which dehumidifier  50  has an affinity) within a working gas, such as air. When the heavier, denser compound/vapor laden gas (dotted arrows) enters an inlet port  64 , it is dried by the surface area of the adsorbent or hygroscopic material  52  within the corresponding passageway  62 . The lighter, drier air (clear arrows) thereafter exits through a port  64 . As the dry air rises, a circulation or “chimney” effect is created within the working environment, as illustrated by the arrows in FIG.  7 . That is, the lighter, drier air rises from the dehumidifier  50  and the heavier, vapor laden air is circulated to enter the dehumidifier  50  (through channels  58  or passages  62 ) so that the water vapor or other constituent of the gas is adsorbed (or absorbed) by material  52 . Surfaces  54  and  56  may also provide some adsorption (or absorption) of the gaseous constituent. 
     It is to be understood that the dehumidifiers  14 ,  30 , and  50  may be constructed of various shapes and sizes depending upon the working space to be dried. Further, the dehumidifiers  14  and  50  may be “tossed” into an enclosed space, such as a case, and will always land and sit “upright” regardless of how they land. That is, the orientation of the dehumidifiers  14  and  50  is always consistent and appropriate regardless of which “side” they rest upon. It is also to be understood that the material  16 ,  32  and  52  may be natural zeolite and that the dehumidifiers of the present invention may be useful in archival of museum, photographic, and other environmentally sensitive material, and protective storage of industrial equipment, and any generally enclosed space in which the humidity or concentration of a gaseous compound is of concern. The material  16 ,  32  and  52  may be shaped and the channels and passages within the material  16 ,  32  and  52  may be formed by machining, extruding or pressing. 
     The present invention thus also provides a process for dehumidifying a gas in an enclosed space, comprising the steps of forming a hygroscopic or adsorbent material into a shape which may be received within the space and to circulate and dry the gas in a desired manner, such as by the chimney effect described herein, activating or otherwise preparing or conditioning the material, such as by drying, and placing the material within the enclosed space. When the material has dried or otherwise adsorbed a sufficient or maximum amount of compound, it may be removed from the enclosed space, reactivated through further drying, and replaced within the enclosed space for additional drying of the space. Alternatively, the material may be reactivated or dried within the enclosed space without removal therefrom. 
     It is to be appreciated that the hygroscopic monolith of the present invention will seek equilibrium with the compound or constituent laden gas within the working space, such activity being facilitated by the shape and surface area of the monolith so as to passively interact with the gaseous environment. As such, the hygroscopic monolith of the present invention may also be used to humidify or otherwise provide a gaseous compound or constituent to a working space. The monolith is charged or conditioned by saturating the monolith with the water or other compound or constituent and placing it within the space having a drier humidity or other ability or affinity to cause the water or other compound/constituent to mix with the gas. In this environment, a downdraft, rather than a chimney effect, is created. As illustrated in FIG. 10, the dehumidifier  14  may be utilized as a humidifier  14 A such that the drier air (clear arrows) enters the humidifier  14 A (passages  22 ) and water vapor or other compound or constituent is adsorbed by the gas and flows outward from the humidifier  14 A (dotted arrows). Similar results can be obtained by saturating the hygroscopic material of FIG. 4 or FIG.  7 . 
     It is to be understood that the present invention provides the ability to facilitate the chimney effect or downdraft effect provided by the hygroscopic monolith so as to modify the composition of a gas in an enclosed space and in a desired manner. For example, when dehumidification is desired, a greater surface area but smaller mass of the hygroscopic material generally results in a quicker drying but less drying capacity. Likewise, a smaller surface area but a greater mass generally provides slower drying but a greater drying capacity. Also, when used as a dehumidifier, the hygroscopic monolith of the present invention is preferably placed in the bottom of an enclosure and when used as a humidifier, it is preferably placed in the top of an enclosure. It is also to be understood that the channels and passageways in the hygroscopic monolith provide a high surface to volume ratio and may be positioned to facilitate air density differences in and around the monolith in the manner described herein. 
     While the hygroscopic monolith of the present invention has been described in connection with preferred embodiments, it is not intended to limit the invention to the particular form set forth, but on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.