Abstract:
A system and a device that are used for liquid-gas phase mass transfer with elimination of contaminants. The systems includes a plurality of liquid membrane-producing cells. Upon contact, the liquid membranes collapse with a gas stream and the collapsed liquid material covers the suspended particles, and eliminates them by decantation. Moreover, the membrane cells increase the speed of the gas stream and cause the gas stream to hit the surface of the liquid at an incident angle of 45°, which serves to improve the transfer of vapor into the gas.

Description:
[0001]     This invention refers to a system and apparatus for transferring vapor molecules from a liquid stream to a gas stream. Particularly, it refers to an air humidification and pollutants filtrating system and the corresponding apparatus. More specifically, a system and an apparatus to filter, humidify, or mix air through collapsible liquid aqueous membranes are described.  
         [0002]     This invention will be described in relation to air humidifiers where liquid molecules (water) are transferred by a mass-transfer phenomenon to a gas stream (air) in contact with the liquid.  
       BACKGROUND OF THE INVENTION  
       [0003]     Atmospheric air is a mixture of dried air, and steam water and is called humid air. This mixture of gases is the one that is conditioned in ambient control systems by means of humidifiers, and conditioned air units. From now on, the word “air” will be used to denote the mixture of dried air, and water vapor as naturally occurring in the atmosphere.  
         [0004]     According to standard 55-1981 from ANSI/ASHRAE (American National Institute of Standards/American Society of Heating, Refrigeration and Air Conditioning Engineers) a series of ideal conditions for comfortable indoor environments were set forth. According to this standard, humidity is a determinant factor for human comfort. At temperatures between 20° C. and 26° C. an indoor environment is comfortable as long as the air humidity is between 30 and 70%.  
         [0005]     From the above, there is a need for humidifiers as co-adjuvants of human comfort.  
         [0006]     In the state of the art, a diverse kind of humidifiers is known; humidifiers are classified according to their functions. Such classification consists of:  
         [0007]     Evaporative humidifiers: In such systems, a fan makes air circulate through a moisturized material. Water contained in the material is transferred to the air stream, thereby increasing the relative humidity of the air stream.  
         [0008]     Liquids have a physicochemical property called vapor pressure. Such property determines the balance between the vapor phase, and the liquid phase of a liquid. By virtue of such property, a liquid will always tend to establish a balance between the liquid and vapor phases.  
         [0009]     The evaporation phenomenon takes place when vapor is generated as a result of the balance between the liquid-vapor phases. If a gas stream absorbs vapor at balance with the liquid phase, fresh vapor will be generated to re-establish the liquid-vapor balance.  
         [0010]     In the evaporative humidifiers, an air stream takes up the vapor that is balanced with the liquid phase, the balance is broken, and new vapor is generated to re-establish the balance. The air that comes out of the humidifier is humid air.  
         [0011]     The evaporative humidifiers have the disadvantage that the moisturized material can become a source for the growth of fungus, algae, and aerobic germs.  
         [0012]     U.S. Pat. No. 4,844,842 published on the 4 th  of Jul., 1989 describes an apparatus of this sort. According to such patent, the moisturizing element being formed as a rotatable disc. The bottom of the disc is submerged in a water bath or in an aqueous liquid while the top is in contact with an air stream. When such disc rotates, the top is submerged in the liquid while the submerged part emerges already wet, and gets in contact with the air stream.  
         [0013]     U.S. Pat. No. 5,945,038 describes an evaporative humidifier that consists of an absorbent material where a portion of the humidification material is submerged, and the upper portion is exposed to air, in such patent the use of a floater to control the water supply is also described.  
         [0014]     Boiling Humidifiers. In such evaporators, an air stream is mixed with a steam stream that was obtained from boiling water.  
         [0015]     Such evaporators have the advantage of eliminating all kinds of microorganisms; however, they generate a “white dust” that consists of insoluble salts and minerals contained in water that are entrained along with the steam streams. On the other hand, boiling humidifiers have the disadvantage of using a great deal of energy to boil water. On the other hand, such humidifiers do not provide the means to remove those pollutants already present in the air stream.  
         [0016]     Warm Mist Humidifiers. These humidifiers operate with water vapor near the dew point temperature. Water vapor is cooled just before contacting the air stream, in such a way that a gaseous mixture of steam water and small droplets of water, and air is obtained.  
         [0017]     Such units have the disadvantage of keeping air pollutants. Besides, such humidifiers do not provide means to remove pollutants present in the air stream either.  
         [0018]     Cold Mist Humidifiers. In these humidifiers, water or an aqueous liquid is sprayed, and then mixed with the air. Such equipment has the disadvantage of keeping the pollutants, and microorganisms in the humid air stream.  
         [0019]     Such humidifiers do not provide the means to remove those pollutants present in the air stream either.  
         [0020]     Ultrasonic humidifiers. These humidifiers use high frequency vibrations to spray, and evaporate water.  
         [0021]     The ultrasonic evaporators have the disadvantage of requiring very costly maintenance. Besides, these humidifiers do not provide the means to remove the pollutants present in the air stream either.  
         [0022]     As above mentioned, the boiling humidifiers, the warm mist humidifiers, the cold mist humidifiers, and the ultrasonic humidifiers do not remove those pollutants present in the air streams so that in such humidifiers, the pollutants are entrained along with the humidified air stream.  
         [0023]     On the other hand, in the case of evaporative vaporizers, still when the dust is removed by filtering the moisturized material, such dust that is in contact with the moisturized material promotes the growth of fungus, algae, and aerobic germs. Besides, as times passes by, the accumulated dust in the moisturized material tends to obstruct the air circulation through the moisturized material, and then affects water transfer to the steam stream.  
         [0024]     To remove dust, different kinds of filters are known. Also, it is known the use of foam to control dust in mining environments, for instance, in carbon mines. The foam is generated by means of ejectors where an air stream is mixed with a water stream at high speeds.  
         [0025]     U.S. Pat. Nos. 4,000,992, and 4,400,220 of Jan. 4 th , 1977, and Aug. 23 rd , 1983, describe a system for dust removal by bubbles into a cyclone.  
         [0026]     Therefore, in the state of the art, there is no evaporator that also removes dust, and pollutants from the humidified air stream without generating fungus, algae, and aerobic germs.  
         [0027]     For this reason, an object of the invention is to provide a system and an apparatus to transfer liquid molecules by evaporation to a gas stream in contact with the liquid.  
         [0028]     For this reason, an object of the invention is to provide a humidifier system and an apparatus capable of eliminating air pollutants.  
         [0029]     Another object of the invention is to provide a humidifier system, and an apparatus capable of eliminating dust and microorganisms from the air stream.  
         [0030]     One more object of the invention is to provide a system of easy maintenance capable of efficiently humidifying, removing air particles, disinfecting, and providing aroma to the air. 
     
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0031]      FIG. 1A  shows the apparatus of this invention.  
         [0032]      FIG. 1B  shows the apparatus of this invention where the internal components of the apparatus are illustrated.  
         [0033]      FIGS. 1C and 1D  respectively show the front and rear components of the apparatus of this invention.  
         [0034]      FIG. 2  shows the sequence of creation and collapse of the liquid membrane to remove solid particles and spray water according to this invention.  
         [0035]      FIG. 3A  shows the means to generate the membrane.  
         [0036]      FIG. 3B  illustrates a membrane cell.  
         [0037]      FIG. 4  shows a membrane disc.  
         [0038]      FIG. 5  shows an assembly plate of membrane discs. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0039]     According to  FIGS. 1A, 1B ,  1 C, and  1 D, the humidifying apparatus of this invention consists of a housing  10  wherein the air convection means  20 , the membrane generation means  30 , the liquid supplying means  40 , the ejection means  50 , and the control means  60  are placed.  
         [0040]     The housing  10  can be made of any material, for instance, metal, glass, wood, or plastic. In home applications, it is preferred to make the housing of plastic. Preferably, the housing material  10  should not chemically react with the gas or the liquid transferred to the gas stream.  
         [0041]     The air convection means  20  comprises any means able to force the convection of air to be purified and humidified inside the humidifying apparatus. In  FIGS. 1A, 1B ,  1 C, and  1 D, such means is illustrated as an axial fan  21 , however, any system that generates an air flow can be used, for example, piston, turbine, radial fan, blower, compressor, etc. Optionally, an external air stream can be used, for example a stream from a pipeline. The gas flow may be intermittent or continuous.  
         [0042]     The air is forced to go through the membrane generation means  30 .  
         [0043]     The membrane generation means  30  consists of a plurality of membrane cells  31  that provides for surfaces to form aqueous membranes. The membrane generation means  30 , and the membrane cells are illustrated in  FIGS. 3A , and  3 B, respectively.  
         [0044]     The plurality of cells  31  is formed from a plurality of discs  32 , and assembly plates  33 . In  FIG. 4 , a disc  32  is shown, and in  FIG. 5  an assembly plate  33  is illustrated.  
         [0045]     The discs have a plurality of slots  321  and a plurality of orifices  322 . The orifices  322  have a perimeter  323 . The shape of the orifice and the shape of the perimeter of the orifice should be suitable to form a liquid membrane. As illustrated in  FIG. 4 , the orifices have an oval shape, and the perimeter of each oval has a wavy shape, in such a way to provide the largest contact surface favoring the formation of liquid membranes. Such arrangement has provided for the best results in membrane creation. Besides, such discs have a void center  324 .  
         [0046]     The assembly plate shown in  FIG. 5  consists of a rectangular plate that has slots  331 , such assembly plate  33  has a similar shape to that of a comb. The slots in the disc match with the slots  331  of the assembly plate to form the membrane generation means  30 , which has a similar structure to that of a cylinder. In  FIG. 1B , the assembly of plates  33  and discs  32  is illustrated.  
         [0047]     As it will be readily apparent for an expert on the art, the discs can have a polygonal shape. The discs with a polygonal shape are considered included within the scope of this invention.  
         [0048]     The center  324  of the discs  32  defines a chamber  35  inside the plurality of membrane cells  31  in a cylindrical arrangement.  
         [0049]     The membrane cells  31  are formed in the spaces between the disc surfaces  32  and the combs  33 . Such cells have the shape of an irregular cube that is widened in one of its faces. The cells  31  are illustrated in  FIG. 3B . The plurality of discs  31  is manufactured of any suitable material to allow forming an aqueous membrane.  
         [0050]     The membrane generation means  30  rotates continuously (or intermittently), so that the membrane cells  31  undergo the following operation stages:  
         [0051]     (1) Liquid immersion;  
         [0052]     (2) Membrane formation;  
         [0053]     (3) Upcoming air and membrane breakage;  
         [0054]     (4) Humid air ejection.  
         [0055]     In  FIG. 2 , there is an outline of stages (1) to (4), where  31  is the membrane formation cell, g is a gaseous stream, and L is the liquid that the liquid membrane forms.  
         [0056]     The stages are described below in relation with the apparatus of this invention.  
         [0000]     (1) Liquid Immersion.  
         [0057]     The membrane generation means  30  are partially immersed in the liquid supplying means  40 . In  FIGS. 1A , and  1 B, such liquid supplying means comprise a liquid container  41  that contains liquid up to a determined liquid level  42 .  
         [0058]     As illustrated in  FIG. 1B , by virtue of the rotation of the membrane generation means  30 , the membrane generation means  30  are submerged in the liquid of container  41  in position A. The liquid completely floods the cells  31 .  
         [0000]     (2) Membrane Formation.  
         [0059]     The disc rotates to position B, where membrane cells  31  that were submerged, now emerge, and the liquid spills over the container  41 . However, by virtue of the surface tension of the liquid, aqueous membranes are generated in each cell  31  emerging from the liquid of container  41 .  
         [0060]     According to  FIG. 3B , a pair of side membranes  311  are formed in side orifices  322  of cell  31 . Besides, an upper membrane  312  is formed in the widest portion of the structure, and a lower membrane  313  in the thinnest portion of cell  31 . In addition, and to a lesser extend, internal membranes that are not illustrated are formed, which are parallel to membranes  312  and  313  in the interior of the membrane cell  31 . Someone or all of the referred membranes may be formed.  
         [0061]     Once the membrane cells  31  emerge from the contained liquid located inside the container  41 , the membranes  311 ,  312  and  313  are formed.  
         [0000]     (3) Upcoming Air and Membrane Breakage.  
         [0062]     The membrane cell  31  with a determined shape is submerged into an especial liquid. An aqueous membrane of the especial liquid is formed, and an airflow is applied to it, so that the membrane collapses and gets sprayed out into thousands of particles. The air suspended particles are trapped by the membrane spray, and are decanted.  
         [0063]     The membrane cells  31  provide the system of the invention with channel, space, and time means for the already humidified particles that are still dispersed in the gas, to precipitate and agglutinate.  
         [0064]     As shown in  FIG. 1B , the induced air by fan  21  is set in contact with membrane cells  31  in the C position.  
         [0065]     The air flow directly collide on the aqueous membranes  311 ,  312 , and  313 , which upon receiving the air flow, collapse, spraying themselves into thousands of small particles of the liquid that formed the membrane.  
         [0066]     The air stream, in the first place, breaks the upper membrane  312 , comes into the interior of the membrane cell  31 , and breaks the side membranes  311  and the intermediate membrane, and finally the lower membrane  313 , immediately entering into chamber  35 .  
         [0067]     The solid particles and pollutants accompanying the gaseous stream are decanted as a result of the saturation they underwent at the time of membrane breakage. This effect traps the suspended particles by changing their weight and precipitating them.  
         [0068]     In order to effectively trap small particles, it is necessary for the particles to enter into contact with the membrane, and make it collapse. While the membrane collapses, the air comes into membrane cell  31 , the membrane implodes, and the liquid film from which the membrane was made of, covers the particle. The smaller the portion of the collapsed membrane is, the smaller the particles that can be trapped. This system traps all of the detectable particles.  
         [0069]     Optionally, the liquid from the membrane may contain a disinfectant, so the trapped particle in the membrane will subsequently be disinfected. The suspended particles can be impregnated with a bactericidal and aroma bio-absorption liquid, causing the killing of bacteria, viruses, and other harmful germs.  
         [0070]     The liquid membranes described herein are collapsed upon contact with the small particles, such as dust, and the portions of the collapsed membrane are capable of humidifying one-micron-size particles. This way, particles in the air are collected and agglutinated.  
         [0071]     Simultaneously, particles from the liquid of the collapsed membrane are transferred to the air stream, and humidify it. Aromatizers can be alternatively aggregated, besides they are transferred to the air stream, and aromatize it. The airflow resulting from the process comes out completely clean, and humidifies, and aromatizes the environment.  
         [0072]     The liquid spray created by virtue of the membrane breakage favors the liquid transfer toward the gaseous stream.  
         [0073]     The membrane cells  31  have an entry area bigger than the exit area, by virtue of such characteristic; the gaseous stream comes out with a higher speed than the speed it comes in.  
         [0074]     By virtue of the shape of membrane cells  31 , similar to an ejector, the air stream coming into membrane cells  31  in positions C, is accelerated and collides at a higher speed on the surface of the liquid contained inside chamber  35 . The air collides on the liquid surface at an optimal angle, close to  450 , strikes with the liquid surface, and absorbs other liquid portion.  
         [0075]     As can be seen in  FIG. 1B , the air comes in only through cells C 1  and C 2 . The later means the airflow can be controlled by calculating the cell dimensions and the rotational speed of the membrane generation means  30 . Consequently, the composition of the escaping gas can be controlled.  
         [0076]     Besides, the air is channeled in the cells at position C ( FIG. 1B ) so that a uniform flow that collides on the liquid surface inside the chamber  35  is obtained.  
         [0077]     By virtue of the membrane generation rotating means, the following is achieved:  
         [0078]     a) Removal of pollutant particles and dust;  
         [0079]     b) Mass-transfer of liquid particles sprayed on the gas stream;  
         [0080]     c) Mass-transfer of liquid particles due to the gas stream collision at an increased speed, and at an optimal angle, close to  450 , on the liquid surface.  
         [0000]     (4) Humidified Air Ejection.  
         [0081]     Once the gaseous stream strikes against the liquid surface, it absorbs a certain amount of liquid; the gas enriched with liquid particles is directed toward the exterior coming out through cells  31  in position D ( FIG. 1B ).  
         [0082]     The cells  31  in position D are uncovered as previously formed membranes on stages A and B were collapsed in stage C. Thus the humidified air freely flows through them toward the exterior of the system.  
         [0083]     The apparatus of this invention comprises also exterior channels  51  placed on the ejection means  50  to uniform the exiting humidified air stream.  
         [0084]     The exterior channels  51  have walls providing a contact surface for the humidified air (enriched air), such surface aims to provide a surface for liquid condensation that over saturates the gaseous stream, so that the additional liquid condensates in such surface and slides toward the interior of the receptacle. This way, the exiting gas contains the proper amount of liquid.  
         [0085]     In addition, the apparatus of this invention comprises electronic or non-electronic control means  60 , to control the switching on and off of the unit, the liquid level in container  41 , the fan speed  21 , and the rotational speed of the membrane generation means  30 , thus controlling the composition of the exiting gas.  
         [0086]     By virtue of the different parts of the system and the apparatus of this invention, the vapor is absorbed in the gaseous stream in the following stages:  
         [0087]     a) At the time following the liquid membrane breakage;  
         [0088]     b) When the gaseous stream makes contact with the liquid surface inside the chamber  35 ;  
         [0089]     c) Upon discharge of the enriched stream through the open cells; and  
         [0090]     d) Upon discharge of the enriched gaseous stream in the exterior channels.  
         [0091]     The higher amount of vapor is transferred to the gaseous stream at the contact stage with the liquid surface inside the chamber  35 .  
         [0092]     As it will be readily apparent to a technician in the art, the gas and liquid streams used in the invention are of any kind depending on the application. For instance, if it is desired to provide a pesticide to an air stream, the liquid should consist of the chosen pesticide and the gas would be air. If it is desired to provide a combustible mixture, the liquid should be selected among any liquid hydrocarbons and the gas should be selected between hydrogen, and oxygen.  
         [0093]     For humidifiers and aromatizers, the liquid consists of water with aromatizing chemical agents and for such applications it is preferred any liquid with bactericidal and bio-absorption soapy abilities.  
         [0094]     The removal system for air suspended particles has an application in electronic appliances for home or office use, for air filtration systems, for decorative or publishing purposes in public areas, for humidifying greenhouses, for apparatus to pour fragrances or chemical agents in controlled amounts, air purifying systems of vehicles, airplanes, etc. And in purification systems of industries, hospitals. For the purification of environmental air, it is possible to combine the system and the apparatus of this invention with removal methods for atmospheric air pollutants, for example, the method described in U.S. Pat. No. 5,227,144 where it is described a procedure for air purification by reaction with chemical products in liquid phase at different stages.  
         [0095]     The liquid membrane generation means  30 , in the preferred embodiment of the invention has been illustrated as a plurality of membrane cells  31  in a cylindrical arrangement. However, as it will be evident for a technician in the art, the arrangement may change. For example, a block of cells through which the air circulates can be placed with the proviso that the liquid supplying means floods or baths such block of cells. A block of cells for membrane generation is considered to be included within the scope of this invention.