Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
  • F24F13/00—Details common to, or for air-conditioning, air-humidification, ventilation or use of air currents for screening
  • F24F13/30—Arrangement or mounting of heat-exchangers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
  • F24F3/00—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems
  • F24F3/12—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling
  • F24F3/14—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification
  • F24F3/1411—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification by absorbing or adsorbing water, e.g. using an hygroscopic desiccant
  • F24F3/1423—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification by absorbing or adsorbing water, e.g. using an hygroscopic desiccant with a moving bed of solid desiccants, e.g. a rotary wheel supporting solid desiccants
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
  • F24F2203/00—Devices or apparatus used for air treatment
  • F24F2203/10—Rotary wheel
  • F24F2203/1032—Desiccant wheel
  • F24F2203/1036—Details
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
  • F24F2203/00—Devices or apparatus used for air treatment
  • F24F2203/10—Rotary wheel
  • F24F2203/104—Heat exchanger wheel

Definitions

• a moisture exchanger for gaseous media which comprises an exchanger body composed by a carrier for a moisture absorbing or hygroscopic material and formed with channels extending from end to end for the passage of the media.
• the carrier has the shape of thin layers or foils, such as paper of cellulose or asbestos. Also plastic substances or glass fibres may come into consideration.
• the layer material shall primarily be fibrous, i.e., composed of, or covered with, fine fibres or threads.
• the channels or passageways extending from end to end in the exchanger body can be formed by making every second layer plane and every interposed second layer corrugated with the corrugations extending in mutually parallel relationship or possibly also by forming the layers to. a honeycomb pattern or providing them with widenings or other spacer elements, ensuring that the layers are spaced from one another.
• the layers may be wound up spirally to form a cylindrical body. If the layers abut against one another, they can be interconnected at the places of contact.
• the moisture exchanger is of .the regenerative type it has a casing to which are connected inlets and outlets for, respectively, the gas, such as air, which is to be desiccated and a gas, such as air, which is heated and serves to remove the moisture taken up by the exchanger body.
• the channels or passageways of the exchanger body are caused alternately to communicate with inlets and outlets, respectively, for the air to be conditioned and for the regenerating gas.
• the exchanger body may be rotatable in which case it moves with low speed between a dewatering'zone and a regenerating zone of the moisture exchanger.
• the exchanger body is stationary while a reversal of the flow of the two media is brought about by means of valves or the like.
• the moisture exchanger can also be used for ventilation of a room or space in which case both consumed room air on its way out, and fresh air on its way into, the room or space, exchange both heat and moisture within the exchanger.
• the moisture exchanger can produce simultaneously with the desiccation also the heat exchange between two media.
• the moisture exchanger may form part of an air conditioning system as is shown, e.g., in the U.S. Pat. No. 2,926,502.
• the carrier in itself hasa moisture absorbing'capacity which at'all events is insignificant, itis caused to take up a particular, moisture absorbing material. it is known to use for this purpose finally powdered silica gel. It is also known to impregnate the carrier with a hygroscopic salt such as lithium chloride, lithium bromide or calcium chloride.
• a hygroscopic salt such as lithium chloride, lithium bromide or calcium chloride.
• Such a salt is capable of absorbing a great quantity of moisture in, relation to its own weight, thus if the salt e.g., is contained in an amount equal to 10 percent by weight in a carrier of asbestos paper, the amount of moisture which can be absorbed can equal from between 25 and 50 up to 100 percent of the weight of the carrier. in return, such salts have no particular great capacity of deep desiccation.
• lithium chloride is capable of desiccating air down to a relative moisture content of l to 2 percent, but on the other hand is capable of absorbing
• molecular sieves which may consist of synthetically produced crystalline, metallic aluminum silicates which have been activated for adsorption by removal of their water of hydration.
• Such molecular sieves obtain a very fine porousity and have a great affinity to water.
• the pores of the molecular sieve have high equal size molecular dimensions which afford to them a high adsorbing capacity within 'a limited range of the relative moisture of the gas.
• the molecular sieves consist of crystalline zeolites which have the basic formula Mz/ o Al Q -xsiO vHQO wIiere M i'QZtitJnEfikYn'ifie'"valeiie. in spite of some similarity in composition, they differ thoroughly from the gel-type amorphous aluminumsilicates, commonly referred to as zeolites, and used for making water soft. The last-mentioned material does not exhibit any selectivity based on molecular size.
• zeolites which to advantage can be used for desiccation, those types may be mentioned which commercially have the denominations 4A and 13X, PQYLafilld the fqllo s ne q Type 13X: Na [(AlO (SiO 276F1 0 The sodium ions in type 4A can be replaced by six calcium ions.
• a moisture adsorbing substance of the kind now described can also be defined as a solid fine powder of crystalline aluminium silicates based on alkali metals or alkali-earth metals, the water of hydration of which has been removed. They may consist of natural or synthetic zeolites or molecular sieves.
• the material can be admixed as a powder into the fibre pulp suspension of which the carrier, such as the cellulose or asbestos paper, is manufactured or the mate rial can be supplied to the finished paper after the exchanger body has been built up.
• the quantity of material may amount from 10 to 25 up to percent and even more of the weight of the carrier.
• the carrier of the exchanger body is supplied with moisture absorbing substances of both kinds'mentioned above, i.e., firstly a water soluble salt and secondly a solid material of the type of zeolite or molecular sieve.
• the secondmentioned material has in this connection the particular effect of having the capcity of desiccating a gas such as air'to a very low relative moisture content such as less than 0.1 percent.
• the molecular sieve has a limited capacity only of adsorbing moisture and according to the invention the two components constitute complements to one another in a'particularly advantageous manner.
• the salt has to manage the preliminary coarse desiccation of the air whereas the other material effects the final desiccation to a very low moisture content.
• the two components can be distributed evenly over the entire exchanger body, even if it is particularly advantageous to subdivide the same into two zones, a first zone which is initially met bythe gas or air to be desiccated and which is impregnated with the salt whereas a second zone at the outlet side of the channels or passageways is impregnated with the molecular sieve or the like means.
• the first zone may have a greater extension in the direction-of flow of gas to be desiccated through the channels or passageways of the exchanger body than the secondzone.
• layers having a thickness of one or some few tenths of a millimeter consist of cellulose or'asbestos.
• the asbestos paper contains organic constituents to obtain required joining of the asbestos fibres. These constituents are removed after the exchanger body has been built up by burning away said constituents as is evident from the US. Pat. No. 3,231,409.
• a moisture exchanger for gaseous media which comprises a carrier for moisture absorbing material formed with channels extending from end to end for the passage of the media, said material consisting of two components, firstly, a water-soluble salt, and secondly, a water-insoluble, solid molecular sieve, said salt having the greater absorbing capacity with respect to the quantity of moisture, and said sieve being of such nature as to possess the capacity of desiccating the media to a lower relative moisture content than said salt.
• a moisture exchanger for gaseous media comprising a fibrous carrier for moisture absorbing material in sheet form arranged in layers and having a plurality of channels extending from end to end of the carrier for passageway therethrough of the media,
• said material being of two kinds, namely, a water soluble salt and a molecular sieve, the sheets being arranged so that the media pass over the salt-carrying sheets before passing over the sieve-carrying sheets.
• every second layer of the carrier is plane and every interposed layer is corrugated, the corrugations being parallel to one another and forming with the plane layers the passageways for the media.
• the crystalline aluminum silicate is in powder form admixed into the fibres of the carrier sheets, and is selected from the group consisting of crystalline alluminum silicates of alkali metals and alkali earth metals.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Drying Of Gases (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=20272680

Family Applications (1)

Country Status (5)

Cited By (21)

Families Citing this family (1)

Citations (9)

• 1970
  • 1970-06-08 SE SE07930/70A patent/SE350329B/xx unknown
• 1971
  • 1971-05-28 GB GB1801871A patent/GB1351527A/en not_active Expired
  • 1971-06-04 US US00150189A patent/US3807149A/en not_active Expired - Lifetime
  • 1971-06-07 FR FR7120585A patent/FR2096024A5/fr not_active Expired
• 1980
  • 1980-03-17 JP JP1980033835U patent/JPS578900Y2/ja not_active Expired

Patent Citations (9)

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