WO2014011655A1 - Milieux de contact pour refroidisseurs à évaporation - Google Patents

Milieux de contact pour refroidisseurs à évaporation Download PDF

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Publication number
WO2014011655A1
WO2014011655A1 PCT/US2013/049757 US2013049757W WO2014011655A1 WO 2014011655 A1 WO2014011655 A1 WO 2014011655A1 US 2013049757 W US2013049757 W US 2013049757W WO 2014011655 A1 WO2014011655 A1 WO 2014011655A1
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Prior art keywords
weight percent
poly
water
imides
polyacrylonitrile
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PCT/US2013/049757
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English (en)
Inventor
Galen W. Hartman
Ronald James Yaeger
Original Assignee
Anne Yaeger
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Priority claimed from US13/545,695 external-priority patent/US8440290B2/en
Application filed by Anne Yaeger filed Critical Anne Yaeger
Publication of WO2014011655A1 publication Critical patent/WO2014011655A1/fr

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F25/00—Component parts of trickle coolers
    • F28F25/02—Component parts of trickle coolers for distributing, circulating, and accumulating liquid
    • F28F25/08—Splashing boards or grids, e.g. for converting liquid sprays into liquid films; Elements or beds for increasing the area of the contact surface
    • F28F25/087—Vertical or inclined sheets; Supports or spacers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B3/00—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form
    • B32B3/26—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer
    • B32B3/28—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer characterised by a layer comprising a deformed thin sheet, i.e. the layer having its entire thickness deformed out of the plane, e.g. corrugated, crumpled
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
    • B32B5/22—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed
    • B32B5/24—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer
    • B32B5/26—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer another layer next to it also being fibrous or filamentary
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F21/00—Constructions of heat-exchange apparatus characterised by the selection of particular materials
    • F28F21/06—Constructions of heat-exchange apparatus characterised by the selection of particular materials of plastics material
    • F28F21/067—Details
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2250/00—Layers arrangement
    • B32B2250/20—All layers being fibrous or filamentary
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2260/00—Layered product comprising an impregnated, embedded, or bonded layer wherein the layer comprises an impregnation, embedding, or binder material
    • B32B2260/02—Composition of the impregnated, bonded or embedded layer
    • B32B2260/021—Fibrous or filamentary layer
    • B32B2260/023—Two or more layers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2260/00—Layered product comprising an impregnated, embedded, or bonded layer wherein the layer comprises an impregnation, embedding, or binder material
    • B32B2260/04—Impregnation, embedding, or binder material
    • B32B2260/046—Synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2262/00—Composition or structural features of fibres which form a fibrous or filamentary layer or are present as additives
    • B32B2262/06—Vegetal fibres
    • B32B2262/062—Cellulose fibres, e.g. cotton
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2262/00—Composition or structural features of fibres which form a fibrous or filamentary layer or are present as additives
    • B32B2262/10—Inorganic fibres
    • B32B2262/101—Glass fibres
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/30—Properties of the layers or laminate having particular thermal properties
    • B32B2307/302—Conductive
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/40—Properties of the layers or laminate having particular optical properties
    • B32B2307/402—Coloured
    • B32B2307/4026—Coloured within the layer by addition of a colorant, e.g. pigments, dyes

Definitions

  • This invention relates in general to gas/liquid contact media.
  • the invention relates to contact media for use in evaporative cooling equipment using water having dissolved and particulate contaminants.
  • evaporative coolers are a popular choice for HVAC (heating/ venting/air conditioning) service, especially in dry climates, as they can simultaneously cool and humidify the air. and do so with considerably less electrical power consumption than conventional refrigerant systems using fluorocarbon refrigerants.
  • evaporative coolers have several problems not present with refrigerant systems, including scale build-up and the growth of mold, algae and other microbes. These problems require regular maintenance, adding to the cost of operation. The added cost of maintenance in some cases can outweigh the cost benefit of lower electrical consumption.
  • Water used in evaporative coolers ordinarily contains dissolved minerals such as carbonates. sulfates, and nitrates of calcium, magnesium, potassium and sodium, which deposit on the contact media as scale. As the water evaporates, the concentration of dissolved minerals increases, causing more rapid scale build-up on the contact media and the formation of particulates in the water. Scale tends to reduce the evaporative efficiency of the contact media, and will eventually clog the passages through which the water and air pass, further reducing evaporator efficiency. Moreover. the added weight from the scale deposits can cause deformation or collapse of insufficiently supported media.
  • the water may become acidic or alkaline, which can also promote deterioration of the contact media. Mold, algae and mildew can also develop that attack the contact media, create objectionable odors and present a potential health hazard.
  • Several methods have been used to address the problems of scale build-up on the contact media: 1 ) use of once-through water or use of recirculating water with a high bleed-off water rate to reduce the concentration of dissolved salts; 2) addition of scale inhibiting chemicals to the recirculated water: and 3) use of untreated recirculated water without bleed-off. along with periodic replacement of the contact media. All of these methods add to the operating and maintenance costs.
  • Replaceable contact media has been made with cellulose, asbestos, or fiberglass sheets. These materials are preferred for their large effective surface area and good wetting properties, which promotes greater evaporation rates for a given amount of material. However, materials having these desired properties often also lack the needed rigidity and water resistance to hold up under typical service for extended periods.
  • Impregnation can increase the overall structure's strength, especially when wet. and thereby increase its durability and resistance to deformation caused by scale build-up.
  • organic and inorganic materials have been used, with organic polymers being a popular choice.
  • U.S. Patent No. 3.262.682. issued to Bredberg and U.S. Patent No. 3.792.841. issued to Munters. teach impregnating cellulose or asbestos sheets with either a phenolic aldehyde resin or a phenolic resin to increase wet strength.
  • Other polymers commonly used in the industry are urea formaldehyde, melamine. and melamine formaldehyde, all of which are thermosetting plastics that are cured on the bulk material. Unfortunately, these polymers tend to break down under contact with acidic or alkaline recirculated water, hydrolyzing back into the original reactants and other smaller compounds that dissolve and are washed away, leaving the bulk material unprotected and unsupported.
  • hydrolysis products are volatile and will vaporize and be blown into the ventilation ducting along with the cooled air. polluting the air in the living space.
  • the remaining. environmentally harmful hydrolysis products remain dissolved in the water, and are usually dumped into the local water table when the cooler is flushed out. because the environmental hazard created by this type of contact media is not generally recognized.
  • U.S. Patent No. 3.798.057 and U.S. Patent No. 3.862.280. both issued to Polvina. disclose the use of a special bulk material that is acid, alkali, and water resistant, impregnated with a combination of a chlorinated (3 or (5 hydrocarbon, a chlorinated terphenyl or chlorinated paraffin (as a plasticizer). and a polyglycidyl ether polyhydric phenol such as bisphenol A or bisphenol F.
  • This impregnating material is claimed to increase durability under pH and temperature extremes that normally cause rapid disintegration of conventional contact materials.
  • thermosetting polymers such as absence of crosslinking.
  • U.S. Patent No. 5.260.1 17 e.g. continued requirement for the absence of crosslinking in thermosetting polymers: separately applied thermosetting polymer layers are said to "fuse" together when the layers actually adhere to each other].
  • the polymer homologs taught in the Meyers et al. references are selected on the basis of mechanical properties such as strength, impact resistance and surface finish and appearance; there is no discussion of chemical properties such as wettability, ionic behavior, and solubility in water.
  • a desirable replaceable contact media will have relatively high water resistance (i.e.. low solubility in water) and retain its strength when wet.
  • the contact media should also resist scale build-up and have improved wetting properties relative to conventional polymers for greater evaporative rates.
  • the contact media preferably will also resist growth of mold, algae, mildew and other microbes. The media should retain these properties and resist chemical breakdown in the presence of acidic or alkaline conditions. As always, a contact media that is less expensive to manufacture is also desired.
  • a structure having the desired features and advantages is achieved by a fibrous material impregnated with a compound to extend the life span and enhance performance of the contact media.
  • the fibrous material has an effective amount of void space between the fibers for more effective surface area and to promote water distribution throughout the media.
  • the impregnating compound has a polymer based continuous phase designed to have solubility and surface properties within preselected limits.
  • the polymer-based continuous phase can be made from a single type of polymer or a mixture of two or more polymers.
  • the polymers selected for use in the compound are insoluble in water and exhibit greater stability under acidic and alkaline conditions than prior art polymers such as phenolics and phenolic aldehydes.
  • the polymer-based continuous phase has surface tension and interfacial tension properties within preselected limits in order to ensure improved wetting by the recirculated water compared to conventional polymers.
  • the impregnating compound is designed to be at least weakly cationic. and preferably strongly cationic in nature to enhance its resistance to scale build-up. Additives can optionally be applied to the continuous phase to resist growth of microbial species and for aesthetics such as color and fragrance. An optional discontinuous phase made up of fillers, pigments and extenders can be dispersed in the continuous phase.
  • the impregnating compound is present in the finished product in an amount ranging f om about three to about sixty percent by weight on a dry basis, with the fibrous material making up the balance.
  • the impregnating compound is present in the finished product in an amount ranging from about five to about twenty five percent by weight on a dry basis. Even more preferably, the impregnating compound in present in the finished product in an amount ranging from about ten to about fifteen percent by weight on a dry basis.
  • the contact media can be made in any suitable shape.
  • the preferred configuration is a series of corrugated sheets stacked together, with adjacent sheets being canted so that the corrugations form channels for water and air flow.
  • the sheets are arranged so that the acute angle formed by the corrugations has a thirty degree span.
  • the stacks of sheets are preferably cut into rectangles so that a line drawn parallel to a side of the rectangle will bisect one of the angles fonned by the corrugations.
  • the contact media of the invention overcomes several drawbacks of the prior art. Recirculating water will wet the new contact media more effectively compared to media impregnated with conventional polymers, yet the contact media has slower scale build-up rates as a result of the impregnating compound's surface properties and overall cationic nature.
  • the impregnating compound can also be designed to be substantially insoluble in water and to be stable in either acidic or alkaline conditions.
  • the present invention provides a water/air contact medium for use in an evaporative cooler, comprising a corrugated fibrous sheet material comprising at least a top layer and a bottom layer in contact at one or more regions to fonn at least two channels between the top layer and the bottom layer for air and fluid flow; and a water insoluble thermoplastic composition that impregnates the corrugated fibrous sheet material, wherein the water insoluble thermoplastic composition comprises between 1-35 weight percent polyvinyl chloride: 1-20 weight percent polyacrylonitrile: 1-60 weight percent poly( methyl aery late): 1-20 weight percent polyamide-imides: and 2-25 weight percent poly( butyl aery late).
  • Specific embodiments include about 2 weight percent polyvinyl chloride: 18 weight percent polyacrylonitrile: 45 weight percent poly(methyl acrylate): 15 weight percent polyamide-imides: and 20 weight percent poly(butyl acrylate). Specific embodiments include about 25 weight percent polyvinyl chloride: 14 weight percent polyacrylonitrile: 36 weight percent poly(methyl acrylate): 10 weight percent polyamide-imides: and 15 weight percent poly(butyl acrylate). Specific embodiments include about 32 weight percent polyvinyl chloride: 13 weight percent polyacrylonitrile: 33 weight percent poly(methyl acrylate): 7 weight percent polyamide-imides: and 15 weight percent poly(butyl acrylate).
  • Specific embodiments include about 34 weight percent polyvinyl chloride: 2 weight percent polyacrylonitrile: 60 weight percent poly( methyl acrylate): 2 weight percent polyamide-imides: and 2 weight percent poly(butyl acrylate). Specific embodiments include about 10 weight percent polyvinyl chloride: 7 weight percent polyacrylonitrile: 11 weight percent poly(methyl acrylate): 13 weight percent polyamide-imides: and 9 weight percent poly(butyl acrylate): and further comprising 24 weight percent polystyrene and 26 weight percent polybutadiene.
  • Specific embodiments include about 10 weight percent polyvinyl chloride: 5 weight percent polyacrylonitrile: 10 weight percent poly(methyl acrylate): 10 weight percent polyamide- imides: and 10 weight percent poly( butyl acrylate): and further comprising 25 weight percent polystyrene and 30 weight percent polybutadiene.
  • Specific embodiments include about 15 weight percent polyvinyl chloride: 2 weight percent polyacrylonitrile: 15 weight percent poly( methyl acrylate): 6 weight percent polyamide-imides: and 14 weight percent poly(butyl acrylate): and further comprising 22 weight percent polystyrene and 26 weight percent polybutadiene.
  • Specific embodiments include about 15 weight percent polyvinyl chloride: 2 weight percent polyacrylonitrile: 15 weight percent poly( methyl acrylate): 5 weight percent polyamide-imides: and 15 weight percent poly(butyl acrylate): and further comprising 20 weight percent polystyrene and 28 weight percent polybutadiene.
  • Specific embodiments include about 8 weight percent polyvinyl chloride: 2 weight percent polyacrylonitrile: 15 weight percent poly(methyl acrylate): 8 weight percent polyamide-imides: and 15 weight percent poly(butyl acrylate): and further comprising 22 weight percent polystyrene and 30 weight percent polybutadiene.
  • Specific embodiments include about 9 weight percent polyvinyl chloride: 3 weight percent polyacrylonitrile: 7 weight percent poly(methyl acrylate): 8 weight percent polyamide-imides: and 9 weight percent poly(butyl acrylate): and further comprising 27 weight percent polystyrene and 37 weight percent polybutadiene.
  • Specific embodiments include about 8 weight percent polyvinyl chloride: 2 weight percent polyacrylonitrile: 15 weight percent poly( methyl aery late): 5 weight percent polyamide- imides: and 15 weight percent poly( butyl aery late): and further comprising 20 weight percent polystyrene and 35 weight percent polybutadiene.
  • Specific embodiments include about 8 weight percent polyvinyl chloride: 2 weight percent polyacrylonitrile: 10 weight percent poly( methyl acrylate): 3 weight percent polyamide-imides: and 10 weight percent poly(butyl acrylate): and further comprising 30 weight percent polystyrene and 37 weight percent polybutadiene.
  • Specific embodiments include about 5 weight percent polyvinyl chloride: 8 weight percent polyacrylonitrile: 5 weight percent poly(methyl acrylate): 15 weight percent polyamide-imides: and 5 weight percent poly( butyl acrylate): and further comprising 30 weight percent polystyrene and 32 weight percent polybutadiene.
  • the present invention also provides a water/air contact medium for use in an evaporative cooler, comprising a corrugated fibrous sheet material comprising at least a top layer and a bottom layer in contact at one or more regions to form at least two channels between the top layer and the bottom layer for air and fluid flow: and a water insoluble thermoplastic compound that impregnates the corrugated fibrous sheet material, wherein the water insoluble thermoplastic compound comprises between 1-10 weight percent polyacrylonitrile: 5-15 weight percent poly( methyl acrylate): 2-10 weight percent polyamide-imides: 5-20 weight percent poly(butyl acrylate): 30-57 weight percent polystyrene and 20-35 weight percent polybutadiene.
  • Specific embodiments include about 7 weight percent polyacrylonitrile: 13 weight percent poly( methyl acrylate): 8 weight percent polyamide-imides: 18 weight percent poly(butyl acrylate): 32 weight percent polystyrene and 22 weight percent polybutadiene. Specific embodiments include about 4 weight percent polyacrylonitrile: 10 weight percent poly( methyl acrylate): 5 weight percent polyamide-imides: 20 weight percent poly(butyl acrylate): 36 weight percent polystyrene and 25 weight percent polybutadiene.
  • Specific embodiments include about 3 weight percent polyacrylonitrile: 4 weight percent poly( methyl acrylate): 3 weight percent polyamide-imides: 8 weight percent poly(butyl acrylate): 55 weight percent polystyrene and 27 weight percent polybutadiene. Specific embodiments include about 1 weight percent polyacrylonitrile: 6 weight percent poly( methyl acrylate): 3 weight percent polyamide-imides: 12 weight percent poly(butyl acrylate): 47 weight percent polystyrene and 31 weight percent polybutadiene.
  • FIG. 1 is a three-dimensional representation of a solubility 'space', including a plot of the largest domain volume of allowed solubility parameter values.
  • FIG. 2 is a plot of a domain range of permissible combinations of filler specific gravity and filler weight percent in the impregnating compound.
  • FIG. 3 is a perspective view of a preferred configuration for the structure of the contact media.
  • Tenns defined herein have meanings as commonly understood by a person of ordinary skill in the areas relevant to the present invention. Tenns such as “a”, “an” and “the” are not intended to refer to only a singular entity, but include the general class of which a specific example may be used for illustration. The terminology herein is used to describe specific embodiments of the invention, but their usage does not delimit the invention, except as outlined in the claims.
  • the abbreviation PVC is used to denote polyvinyl chloride.
  • the abbreviation PAN is used to denote polyacrylonitrile.
  • the abbreviation PMA is used to denote poly( methyl aery late).
  • PAI is used to denote polyamide- imides.
  • the abbreviation PBA is used to denote poly(butyl acrylate).
  • the abbreviation PS is used to denote polystyrene.
  • the abbreviation PBD is used to denote polybutadiene.
  • CPMA-AN is used to denote a copolymer of methyl acrylate and acrylonitrile.
  • abbreviation CPBA-AI is used to denote a copolymer of butyl acrylate and amide-imides.
  • abbreviation CPS- BD is used to denote a copolymer of styrene and butadiene.
  • the contact media of the invention is made up of two major components, which will be labeled Component I and Component II for convenience.
  • Component I is a fibrous material fonned into a suitable shape.
  • Component II is impregnated into and affixed to the fibrous material and has a continuous phase based on one or more polymers.
  • Component II makes up from three to sixty percent by weight of the finished product on a dry basis. Preferably.
  • Component II makes up from about five to about twenty-five percent by weight of the finished product, and more preferably makes up from about ten percent to about fifteen percent by weight. In each case.
  • Component I makes up the balance of the total weight of the contact media.
  • Component I can be made from a number of standard fibrous materials known in the industry such as cellulose, fiberglass, and asbestos or combinations thereof.
  • the fibrous material should have suitable rigidity, high surface area, light weight (i.e.. low density), and relatively low cost, so that its regular replacement will be economically acceptable.
  • the media can be configured in stacked arrays or formed into drip pads, sprayed pads, packed cells, rotating wheels, or other shapes.
  • Component II is a continuous phase having one or more polymers, which can be either thermoplastic or thermosetting types of plastic, or a combination of both.
  • the final weight average molecular weight of each polymer should be at least about 2500 g/mole.
  • Suitable polymers include epoxies. polyacetals. polyacrylates. polyacrylics. polyacrylamides. polyalkylamides. polyamides. polyamideimides. polycarbonates, polycarboxylicdihydric esters, polyimides. polyesters, polycellulose acetate butyrates. polydiglycidyletheralkyl/aryldiols. polysilicones. polysiloxanes. polysiloxides.
  • polystyrenes polysucrose acetate butyrates. polysulfonamides. polysulfones. polyurethanes. polyvinylacetals. and polyvinylhalogens.
  • the polymer can be one of the above enumerated types, or a combination of two or more types, as well as copolymers of the above in whole or in part, and other polymers known in the art or that will become known in the art as substitutes.
  • the polymers used should be stable in acidic and alkaline conditions normally encountered in recirculating water.
  • Component A can optionally include transient and or permanent plasticizers such as dialkyl/aryl phthalates. dialkyl/aryl adipates. dialkyl/aryl maleates. dialkyl/aryl succinates, dialkyl/aryl sebacates. polyalkyl/aryl phosphates, polyesters, and condensation polymers and resins known in the art as plasticizers and flexibilizers.
  • V is the parameter value and Xi is the mole fraction of the ith component.
  • solubility of a material can be described by three solubility parameters, which will be represented for convenience by the symbols ⁇ n, ⁇ p, and ⁇ h. These parameters are measures of the solubility of the material with respect to the nonpolar. polar, and hydrogen-bonding aspects of the material, respectively, and are expressed in units of g-cal/mole. They can be determined experimentally, or calculated by a method to be discussed.
  • the nonpolar parameter on mainly describes the physical aspects of the material's solubility, while the polar and hydrogen-bonding parameters ⁇ p and ⁇ h primarily describe the chemical aspects of the solubility of the material.
  • the total solubility parameter ⁇ t can also be derived using the Haggenmacher equation for vapor pressure, which can be expressed as:
  • Fp and Ft are the molar cohesion constants for the individual compounds at constant pressure and constant temperature, respectively. These constants are based on the chemical structural identity of the polymers. Tables of these constants for various chemical functional groups, found by experiment, are available from sources such as the CRC Press. Inc.. "Handbook of Chemistry and Physics.” 63rd Edition. 1982-1983. pages C-732 to C-734. Values for some common functional groups are listed in Table 1. Having determined ⁇ p and ⁇ h. the nonpolar parameter On can then be derived from Eq. (2):
  • n 1/(2 ⁇ t ) where ⁇ t is the sum of the aggregation constants for the repeating unit of the segment in the polymer chain.
  • ⁇ VTg is the sum of the group molar volume constants for the repeating unit at the glass transition temperature.
  • ⁇ * represents the aggregation constant for a polymer chain having a weight average molecular weight greater than about 1000.
  • the chain aggregation number is applied in the same manner as the lower molecular value al and can be calculated from the following equation:
  • the three solubility parameters for the polymer mixture are limited to specific ranges.
  • Table 2 lists the range limits as minimum and maximum values for three embodiments, listed from left to right in increasing amount of preference. To aid in visualizing the range of possible values for the solubility parameters.
  • FIG. 1 shows the volume domain defined in the solubility 'space' by the ranges of the solubility parameters for the embodiment having the largest range of values.
  • the volume domain is a rectangular solid offset from the origin along the nonpolar parameter ⁇ axis by 6.5 g-cal/mole.
  • the minimum value for ⁇ n the three embodiments of Table 2 would be represented by three nested rectangular solids, like boxes in boxes.
  • Table 3 lists five examples of polymer mixtures that can be used to make an impregnating compound continuous phase having solubility parameters falling within the specified ranges in Table 2.
  • the resulting solubility parameters for each example are listed in Table 4 in g-cal/mole. In both tables, values listed for individual components in each example are expressed as weight percent.
  • the compatibility of the polymer components should be considered.
  • the degree of compatibility between any two components is proportional to the distance between the points that represent the two polymers in the solubility 'space'. A shorter distance between the points represents greater compatibility between the polymers.
  • the polymer mixture is designed to be insoluble with both water and the scale-depositing species in the water.
  • the scale depositing species dissolve relatively well in water because of their high solubility (i.e. proximity in the solubility 'space') with water.
  • the value for ⁇ h. (the hydrogen-bonding parameter) is much greater than the values for the polar and nonpolar parameters.
  • the polymer mixture is designed to have a value for the hydrogen-bonding parameter that is much smaller than the value for either the water or the scale-depositing species. The difference in relative sizes of the hydrogen bonding parameters is the main reason why the polymer is insoluble with both the water and the scale- depositing species.
  • the insolubility of the polymer with the scale depositing species helps to prevent any initial deposition of scale on the polymer surface. This is very important, because once a monoatomic scale layer is deposited on the polymer surface, the polymer effectively has little or no influence on the scale buildup rate.
  • the scale build-up rate is then governed by the affinity of scale-depositing species to bond to the existing scale layer. This affinity results in a scale build-up rate that is exponentially greater than the rate at which the scale will deposit on the polymer.
  • Interfacial tension describes behavior at solid/solid, liquid liquid, and solid/liquid interfaces. Higher interfacial tensions yield less intimate contact of the components on each side of the interface. For solid/liquid interfaces, this means there will be less wetting of the interfacial surface by the liquid. As in the case of solubility, the impregnating compound needs to be designed with surface tensions and interfacial tensions within acceptable limits so that water will intimately contact the impregnated media to achieve optimal evaporation rates. Distinction will be made between pure water and typical in-service water, when the distinction is relevant.
  • ⁇ is the surface tension.
  • G the Gibbs free energy of the system, and A the surface area of the interface.
  • the specific surface free energy fh is the free energy per unit surface area, which can be expressed for a system having n components as a function of the surface tension and the component concentrations as follows: 12 )
  • yd is the dispersion component arising from dispersion force interaction
  • ⁇ the polar component arising from various dipolar and polar interactions
  • ⁇ the hydrogen bonding component arising from the hydrogen bonding character and tendency.
  • the dispersion component yd. the polar component ⁇ . and the hydrogen bonding component ⁇ are calculated from the previously discussed solubility parameters:
  • the interfacial tension can be calculated from the surface tension and the dispersion, polarity, and hydrogen bonding components of the two contiguous phases using the harmonic mean equation. shown in C. M. Hansen. "The Three Dimensional Solubility Parameter and Solvent Diffusion Coefficient”. Danish Technical Press. Copenhagen. 1967 and in S. Wu. "Polymer Interface and Adhesion”. Marcel Dekker. New York. 1982:
  • the interfacial tension value at this intersection is called the critical surface tension ⁇ c Liquids at the critical surface tension ⁇ c would completely wet the polymer surface with a contact angle of zero degrees.
  • the following equations identify the relationship of surface tension and contact angle: where ⁇ s is the surface tension of the solid phase: ⁇ . is the surface tension of the liquid phase: IIe is the equilibrium spreading pressure: and ⁇ is the contact angle. Equations 20 and 21 and the critical surface tension can then be used to find surface tensions and interfacial tension for a particular system.
  • Table 6 lists the minimum and maximum values for three preferred ranges, listed from left to right in increasing amount of preference as in Table 2.
  • Tables 7 and 8 list the surface tension and interfacial tension values of the example polymer components for the five example polymer mixtures listed in Table 3.
  • Table 7 lists values with pure water as the liquid, while Table 8 is for typical in-service water.
  • Table 3 the values listed for individual components in each example are expressed as weight percent.
  • Table 9 lists the surface and interfacial tensions for the resulting impregnating compound continuous phases for both Tables 7 and 8.
  • the polymer mixture is designed to have higher surface tensions (and therefore lower inter facial tensions with water) than polymers used in the prior art contact media.
  • in-service water will have more intimate contact with the polymer mixture than it will with prior art polymers.
  • more scale depositing will occur with the polymer mixture than with the prior art contact media, which would be undesirable.
  • the tendency for scale build-up is not as great as it seems, due to other factors designed into the polymer mixture that opposes scale deposition.
  • One of these is the high degree of difference of the solubility parameters of the polymer mixture and the scale-depositing species, as was previously discussed.
  • a second factor is the choice of polymers that are generally cationic in nature, so that the polymer will repel positively charged ions and particles in the water.
  • Polymers are composed of cationic and anionic groups, present as part of the polymer backbone and as pendant structures attached to the backbone.
  • Pendant ionic groups have much more ionic character and influence than do those in the backbone. Therefore, polymers having a high density of pendant cationic groups are preferred.
  • Table 10 schematically depicts nine examples of pendant groups, showing how they bond to the polymer backbone. Rp represents a cationic group and Rn represents an anionic group. The formula groups are illustrated in decreasing order of cationic character from top left to bottom right:
  • Table 1 1 lists a number of organic cationic groups that can be substituted for Rp in Table 10. Like Table 10. the groups are shown in decreasing order of cationic strength from top left to bottom right. Likewise. Table 12 lists a number of organic anionic groups that can be substituted for Rn in Table 10. in decreasing order of cationic strength (i.e. increasing order of anionic strength) from top left to bottom right.
  • the impregnating compound can optionally include one or more of the following materials: ( 1 ) fillers and or extenders in particulate or fibrous fonn. (2) glass particulates and fibers, and (3) pigments. These materials are present as a discontinuous phase that is evenly dispersed in the continuous phase of the polymer mixture.
  • the discontinuous phase can include materials such as carbon blacks, calcium silicates, calcium carbonates, aluminum silicates, calcium sulfates, barium sulfates, silicon dioxides, aluminum/silicon oxides, magnesium silicates.
  • the discontinuous phase can make up as much as about forty percent of the total weight of the impregnating compound.
  • the pigments, fillers and extenders can be materials having high thermal conductivity such as particulate aluminum, graphite, and carbon black to increase the thermal transfer between the contact media and the surrounding environment.
  • the ingredients of the discontinuous phase need to remain evenly dispersed in the polymer mixture until the impregnating compound becomes viscous enough to ensure uniformity of the chemical and physical properties throughout the contact media. Also, the sum of discontinuous phase density and weight percentage should be low enough to prevent the contact media from collapsing under its own weight in use.
  • FIG. 2 depicts a graph of the weight percentage of the impregnating compound due to the discontinuous phase along the vertical axis versus the specific gravity of the discontinuous phase along the horizontal axis.
  • the curve plotted on the graph is the upper constraint on permissible combinations of weight percentage of filler content and specific gravity. with the area below the curve being the permissible range.
  • the curve of FIG. 2 can be expressed as fourth power polynomial equations, where x represents the specific gravity of the Component B mixture and y represents the percent of the impregnating compound made up by the discontinuous phase:
  • the impregnating compound can optionally include compounds to prohibit the growth of molds, fungi, mildew, algae. bacteria, and other microorganisms. These additives can make up as much as thirty percent by weight of the impregnating compound.
  • Some suggested compounds include metallic oxides (such as titanium oxide, antimony oxide, zinc oxide, and cuprous oxide), cationic metaborates. boric acid, cationic carbonates, alkyl/aryl chlorides, arylmetalosalicilates. arylmetalooleates. quinolinates. and alkylarylchlorophenols. Since some of these materials can become part of the continuous phase. care should be taken when choosing these components to maintain the solubility, surface tension, and interfacial tension properties of the continuous phase within the ranges previously described, as well as to maintain overall cationic character of the impregnating compound.
  • Pigment and fragrances can optionally be added as well for aesthetic appeal, and can make up as much as four percent by weight of the impregnating compound. Care should also be taken when choosing these additives to maintain the solubility, surface tension, and interfacial tension properties within the ranges previously described, as well as to maintain overall cationic character of the impregnating compound.
  • FIG. 3 shows the preferred structural configuration of the contact media 11 of the invention.
  • the media is made up of several individual sheets 13 of impregnated fibrous material, shaped into corrugated sheets and stacked together with the corrugations in adjacent sheets at different angles to form channels 15 for water and air flow.
  • the sheets are arranged so that each of the acute angles formed by the corrugations has a thirty degrees span.
  • the stacks of sheets are preferably cut into rectangles with the acute angles oriented symmetrically about one of the rectangle's centerlines.
  • the impregnating compound can be applied to the fibrous material in a single layer, or applied in a series of layers that will adhere together.
  • the impregnating compound can be applied so that the Component I fibrous material's surface area is either partially or completely covered.
  • the effective surface area will actually decrease and reduce evaporation rates.
  • the underlying structure is completely covered with the impregnating compound, another embodiment of the invention is possible as a variation on the preferred production method.
  • An unsuitable material can be applied to the fibrous material first as an intermediate layer, then completely covered by the impregnating compound, where the term 'unsuitable material' is defined as any material used in the art for coating or impregnating contact media that does not have solubility parameters within the ranges disclosed for the impregnating compound, including without limitation the materials disclosed in the Background of the Invention.
  • the final, multi-layer product would exhibit the same performance and advantages as a structure not having the intermediate layer.
  • compositions of the instant invention are listed in the table below:
  • example 1 is a composition that includes 100% PAI
  • example 2 is a composition that includes 90% PAI and 10% PS.
  • one embodiment of the present invention provides a water/air contact medium for use in an evaporative cooler, comprising a corrugated fibrous sheet material comprising at least a top layer and a bottom layer in contact at one or more regions to fonn at least two channels between the top layer and the bottom layer for air and fluid flow; and a water insoluble thermoplastic compound that impregnates the corrugated fibrous sheet material.
  • the water insoluble thermoplastic compound may have between 1-35 weight percent PVC: 1-20 weight percent PAN; 1-60 weight percent PMA; 1-20 weight percent PAI; and 2-25 weight percent PBA.
  • the composition may have about 2 weight percent PVC; 18 weight percent PAN; 45 weight percent PMA; 15 weight percent PAI: 20 weight percent PBA.
  • the composition may have about 25 weight percent PVC: 14 weight percent PAN; 36 weight percent PMA; 10 weight percent PAI: 15 weight percent PBA.
  • the composition may have about 32 weight percent PVC: 13 weight percent PAN;33 weight percent PMA; 7 weight percent PAI: 15 weight percent PBA.
  • the composition may have about 34 weight percent PVC: 2 weight percent PAN; 60 weight percent PMA; 2 weight percent PAI: 2 weight percent PBA.
  • the composition may further have between 15-35 weight percent PS and between 20-40 weight percent PBD.
  • the composition may have about 10 weight percent PVC: 7 weight percent PAN; 11 weight percent PMA; 13 weight percent PAI: 9 weight percent PBA; 24 weight percent PS and 26 weight percent PBD.
  • the composition may have about 10 weight percent PVC: 5 weight percent PAN; 10 weight percent PMA; 10 weight percent PAI: 10 weight percent PBA; 25 weight percent PS and 30 weight percent PBD.
  • the composition may have about 15 weight percent PVC: 2 weight percent PAN; 15 weight percent PMA; 6 weight percent PAI: 14 weight percent PBA; 22 weight percent PS and 26 weight percent PBD.
  • the composition may have about 15 weight percent PVC: 2 weight percent PAN; 15 weight percent PMA; 5 weight percent PAI: 15 weight percent PBA; 20 weight percent PS and 28 weight percent PBD.
  • the composition may have about 8 weight percent PVC: 2 weight percent PAN; 15 weight percent PMA; 8 weight percent PAI: 15 weight percent PBA; 22 weight percent PS and 30 weight percent PBD.
  • the composition may have about 9 weight percent PVC: 3 weight percent PAN; 7 weight percent PMA; 8 weight percent PAI: 9 weight percent PBA; 27 weight percent PS and 37 weight percent PBD.
  • the composition may have about 8 weight percent PVC: 2 weight percent PAN; 15 weight percent PMA; 5 weight percent PAI: 15 weight percent PBA; 20 weight percent PS and 35 weight percent PBD.
  • the composition may have about 8 weight percent PVC: 2 weight percent PAN; 10 weight percent PMA; 3 weight percent PAI: 10 weight percent PBA; 30 weight percent PS and 37 weight percent PBD.
  • the composition may have about 5 weight percent PVC: 8 weight percent PAN; 5 weight percent PMA; 15 weight percent PAI: 5 weight percent PBA; 30 weight percent PS and 32 weight percent PBD.
  • another embodiment of the present invention provides a water/air contact medium for use in an evaporative cooler, comprising a corrugated fibrous sheet material comprising at least a top layer and a bottom layer in contact at one or more regions to form at least two channels between the top layer and the bottom layer for air and fluid flow: and a water insoluble thermoplastic compound that impregnates the corrugated fibrous sheet material.
  • the water insoluble thermoplastic compound may have between 1-10 weight percent PAN; 5-15 weight percent PMA; 2-10 weight percent PAI: 5-20 weight percent PBA; 30-57 weight percent PS and 20-35 weight percent PBD.
  • the composition may have about 7 weight percent PAN; 13 weight percent PMA; 8 weight percent PAI: 18 weight percent PBA; 32 weight percent PS and 22 weight percent PBD.
  • the composition may have about 4 weight percent PAN; 10 weight percent PMA; 5 weight percent PAI: 20 weight percent PBA; 36 weight percent PS and 25 weight percent PBD.
  • the composition may have about 3 weight percent PAN; 4 weight percent PMA; 3 weight percent PAI: 8 weight percent PBA; 55 weight percent PS and 27 weight percent PBD.
  • the composition may have about 1 weight percent PAN; 6 weight percent PMA; 3 weight percent PAI: 12 weight percent PBA; 47 weight percent PS and 31 weight percent PBD.
  • A. B. C. or combinations thereof * refers to all permutations and combinations of the listed items preceding the tenn.
  • A. B. C. or combinations thereof * is intended to include at least one of: A. B. C. AB. AC. BC. or ABC. and if order is important in a particular context, also BA. CA. CB. CBA. BCA. ACB. BAC. or CAB.
  • expressly included are combinations that contain repeats of one or more item or tenn. such as BB. AAA. MB. BBC. AAABCCCC. CBBAAA. CABABB. and so forth.
  • the skilled artisan will understand that typically there is no limit on the number of items or terms in any combination, unless otherwise apparent from the context.
  • compositions and/or methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While the compositions and methods of this invention have been described in terms of preferred embodiments, it will be apparent to those of skill in the art that variations may be applied to the compositions and/or methods and in the steps or in the sequence of steps of the method described herein without departing from the concept, spirit and scope of the invention. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and concept of the invention as defined by the appended claims.

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Abstract

La présente invention comprend un milieu de contact à utiliser dans un refroidisseur à évaporation, comprenant un matériau en feuille fibreux ondulé comprenant au moins une couche supérieure et une couche inférieure en contact au niveau d'une ou de plusieurs régions afin de former au moins deux canaux entre la couche supérieure et la couche inférieure pour l'écoulement d'air et de fluide ; et un composé thermoplastique insoluble dans l'eau qui imprègne le matériau en feuille fibreux ondulé. Le composé thermoplastique insoluble dans l'eau peut comporter entre 1 et 35 % en poids de PVC ; entre 1 et 20 % en poids de PAN ; entre 1 et 60 % en poids de PMA ; entre 1 et 20 % en poids de PAI ; et entre 2 et 25 % en poids de PBA. Par exemple, la composition peut comporter environ 2 % en poids de PVC ; 18 % en poids de PAN ; 45 % en poids de PMA ; 15 % en poids de PAI ; et 20 % en poids de PBA.
PCT/US2013/049757 2012-07-10 2013-07-09 Milieux de contact pour refroidisseurs à évaporation WO2014011655A1 (fr)

Applications Claiming Priority (2)

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US13/545,695 US8440290B2 (en) 1999-10-22 2012-07-10 Contact media for evaporative coolers
US13/545,695 2012-07-10

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3792841A (en) * 1963-07-04 1974-02-19 C Munters Liquid and gas contact apparatus
US3862280A (en) * 1971-10-05 1975-01-21 Munters Ab Carl Apparatus for gas-liquid contact
WO1998015783A1 (fr) * 1996-10-04 1998-04-16 Daramic, Inc. Dispositif de refroidissement d'air
WO2001090718A1 (fr) * 2000-05-22 2001-11-29 Forschungszentrum Jülich GmbH Procede et dispositif pour determiner la concentration d'analytes
US20050001339A1 (en) * 1999-10-22 2005-01-06 Yaeger Ronald J. Contact media for evaporative coolers

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3792841A (en) * 1963-07-04 1974-02-19 C Munters Liquid and gas contact apparatus
US3862280A (en) * 1971-10-05 1975-01-21 Munters Ab Carl Apparatus for gas-liquid contact
WO1998015783A1 (fr) * 1996-10-04 1998-04-16 Daramic, Inc. Dispositif de refroidissement d'air
US20050001339A1 (en) * 1999-10-22 2005-01-06 Yaeger Ronald J. Contact media for evaporative coolers
WO2001090718A1 (fr) * 2000-05-22 2001-11-29 Forschungszentrum Jülich GmbH Procede et dispositif pour determiner la concentration d'analytes

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