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Title:
MONO-FILAMENT FABRIC DEVICE FOR EVAPORATION OF LIQUIDS AND REMOVAL OF SALT PRESIPITATION DEPOSITIONS
Document Type and Number:
WIPO Patent Application WO/2010/082204
Kind Code:
A1
Abstract:
The invention relates to a mono-filament knit fabric used as a device for evaporation of liquids and the removal of solid salts precipitation depositions from the liquid, accumulated on the fabric. The mono-filament knit fabric reversibly fluctuates, at will, between stretched and relaxed states. Salt precipitations accumulate in coating-layers on and between the filaments in the relaxed state and the coating-layers are fragmented, released and removed from the filaments upon stretching of the fabric.

Inventors:
GAVRIELI JONAH (IL)
HASCALOVICH PINHAS (IL)
SHABTAI MICHAEL (IL)
Application Number:
PCT/IL2010/000044
Publication Date:
July 22, 2010
Filing Date:
January 17, 2010
Export Citation:
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Assignee:
GAVRIELI JONAH (IL)
HASCALOVICH PINHAS (IL)
SHABTAI MICHAEL (IL)
International Classes:
C02F1/28; D03D25/00
Domestic Patent References:
WO2009004612A22009-01-08
Foreign References:
US20080096001A12008-04-24
Attorney, Agent or Firm:
PATENTICK - IP PORTFOLIO MANAGEMNET (Beit Hananya, IL)
Download PDF:
Claims:
CLAIMS

1. A device for evaporating liquid material from a liquid solution comprising dissolved salt ions and cations and a dissolving liquid and the removal of precipitated and deposited salt material from said evaporated dissolving liquid martial, comprising at least one evaporation medium substrate comprising a three dimensional knit configuration made of knitted polymeric fiber which substantially resumes the initial configuration after it is released from stretching or compressing forces.

2. The device as claimed in claim 1, wherein the evaporation medium substrate has a dimension which changes substantially more than other orthogonal dimensions of the substrate, when subjected to stretching or compressing forces.

3. The device as claimed in claim 1, wherein the polymeric fiber is made from material selected from a group of polymer compounds consisting Polyamide, Polyester, Polyurethane, Polyvinyl, Acryl, Polyethylene, Polypropylene, Polycarbonate, PEEK, and Polystyrene.

4. The device as claimed in claim 1, wherein the evaporation medium substrate further comprising a salt deposition retaining material

5. The device as claimed in claim 4, wherein stretching the evaporation medium substrate releases salt depositions material from said substrate.

6. The device as claimed in claim 1, wherein the liquid solution further comprising plurality of dissolved ions.

7. The device as claimed in claim 1, wherein the liquid solution further comprising plurality of dissolved cations.

8. The device as claimed in claim 1, wherein the liquid solution comprising at least one dissolved inorganic salt material.

9. The device as claimed in claim 1, wherein the liquid solution comprising at least one dissolved organic salt material.

10. The device as claimed in claim 1, wherein the knitted polymeric fiber evaporation medium substrate is in a drum formation.

11. The device as claimed in claim 1, wherein the knitted polymeric fiber evaporation medium substrate is in a flat sheet formation.

12. The device as claimed in claim 1, wherein the knitted polymeric fiber evaporation medium substrate is in a loop band formation.

13. The device as claimed in claim 1, wherein stretching of the knitted polymeric fiber evaporation medium substrate is done mechanically.

14. The device as claimed in claim 1, wherein stretching of the knitted polymeric fiber evaporation medium substrate is done manually.

Description:
MONO-FILAMENT FABRIC DEVICE FOR EVAPORATION OF LIQUIDS AND REMOVAL OF SALT PRESIPITATION DEPOSITIONS

FIELD OF THE INVENTION

[0001] The present invention relates to a fabric used as a device for evaporation of liquids and the removal of solid salts precipitation depositions from the liquid, accumulated on the fabric. More specifically, the device relates to a knit fabric serving as an evaporation medium made of mono-filaments. The said fabric reversibly fluctuates, at will, between stretched and relaxed states. Salt precipitations from evaporated liquid salt solutions accumulate in coating-layers on and between the filaments in the relaxed state of the fabric. When the fabric is stretched the coating- layers are fragmented, released and removed from the filaments. Following the removal of the salt precipitations the fabric is relaxed and ready for fresh reuse.

BACKGROUND OF THE INVENTION

[0002] Liquid dissolved cations and ions (organic and inorganic) that exceed then- solubility saturation-concentration precipitate from the liquid as solid salt particles and deposit on surfaces which are in contact with the liquid. Typically the precipitation depositions form mats. The rate and amount of precipitation depends on the concentration as well as the chemical characteristics of the cations and ions involved. . The rate and amount of precipitation also depends on the cations and ions mixture ratio, the pH and temperature of the dissolving liquid.

[0003] Precipitation of inorganic solid salt mats (composed of salt crystal particles) from over-saturated liquids with concentrations of cations and ions is utilized favorably in many industrial processes. For example: water is commonly used for the precipitation of sodium-chloride (NaCl, known commonly as "table salt" or halite) from evaporated seawater or the precipitation of agriculturally used potassium-magnesium-tri-chloride (KMgCB commonly known as carnallite) from the evaporated water of the Dead-Sea.

[0004] The phenomena of precipitation of solid salt particles from liquid solutions of ions and cations also cause adverse results. [0005] A typical example of such an adverse result is the precipitation of calcium- carbonate (CaCO3) and/or magnesium-carbonate (MgCO3) in residential-used humidifier-systems. Residentially used humidifier-systems are used for a range causes such as (but not limited to) reduction of air borne allergens, exerting an overall better physical feeling and the extension of the life of home furnishings, hardwood flooring. Humidifier-systems are typically used in conjunction with house heating-systems that dry the ambient air as they heat their surroundings.

[0006] Two types of commonly used humidifying-systems are described below:

[0007] The "drum system" has a foam or fabric belt that spins on a drum over a water reservoir. The belt wicks moisture from the reservoir. When the furnace or air- conditioner blows air across the walls of the drum or through the length of the drum, the moisture evaporates into the air and is carried to the ambient air of the house. If the water put in the reservoir contains a relatively high concentration of dissolved calcium and magnesium ions, (commonly known as "hard water"), as is the case in many municipal water distribution networks throughout the world, a hard, "rock" layer of calcium-carbonate and/or magnesium-carbonate gradually builds and coats the foam or fabric belt in the course of operation. With much of the foam or fabric coated the belt no longer conveys the desired amount of water from the reservoir to be evaporated. For continual operation the humidifying "drum system" has to be periodically stopped for maintenance. Typically maintenance requires disassembling the drum and mechanically removing, with or without the use of chemical dissolving agents, the belt-coating layer.

[0008] The "flow through system" that operates by dripping water through a pad made of a porous material that enables the relative free passage of air through the wet pad. Pads are produced from various materials and have various configurations such as: rigid plastic foams, mashed and lose strings and wires, dense-nets, various kinds of proliferated fabrics and metallic plates. A furnace or an air-conditioner blows air through the pad, picking up moisture (evaporating the water) and delivering it to the ambient air in the house. In the course of using hard water a calcium carbonate and/or magnesium carbonate coating layer gradually builds and covers the pad till no air is able to flow through. Periodic maintenance requires either replacing of the pad or mechanically removing, with or without the use of chemical dissolving agents, the pad- covering layer that had formed.

[0009] Typically, devices based on the technology of the "flow through system" are used for cooling houses located in warm and dry locations (in desert or semi arid places) where the devices are at times referred to as a "desert coolers". In desert coolers ambient-temperature dry air is blown through wet (or moist) pads and evaporates the water in the pads while cooling the out-flowing air at the expense of the energy utilized for the evaporation. Similarly to the hindering salt crystal coating layers that effect the operation of "flow through system" humidifying-systems, calcium carbonate and/or magnesium carbonate coating layers hinder the operation of desert-coolers and require the same periodical maintenance as previously described.

[0010] Another field in which the development of calcium carbonate and/or magnesium carbonate coating-layers can hinder device-operations is in cooling towers. Typically the efficiency of a cooling tower depends on the availability of surface-medium-area so as to enable as much as possible contact of the warm-to-be-cooled water with the cooler air, allowing the circulating water to evaporate. In order to maintain hard-water-using cooling towers in high efficiency operating condition, periodic removal of clogging calcium carbonate and/or magnesium carbonate coating-layers from the water passages is necessary. Cooling-tower medium refreshing is done by physically scrubbing, breaking and removing the coating-layers, with or without the aid of strong chemical dissolving agents. The refreshing and maintenance procedure requires the stopping of the operation of the cooling tower and the efforts, time and expenditure for the treatment of the coating layers.

[0011] The device of the present invention is not limited to inorganic ions and cations dissolved in water (as given in the examples above) and is applicable also to organic ions and cations dissolved in organic or inorganic liquid solvents.

[0012] Mono-filament fabrics that fluctuate reversibly and at will between stretched and relaxed states, utilized in the present invention have been previously described in WO2006033101 (Hascalovich) and PCT/IL 08/00888 (Gavrieli and Hascalovich). SUMMARY OF THE INVENTION

[0013] There is thus provided, in accordance with embodiments of the present invention, a device for evaporating liquid material from a liquid solution comprising dissolved salt ions and cations and a dissolving liquid material and the removal of precipitated and deposited salt material from said evaporated dissolving liquid martial, comprising at least one evaporation medium substrate comprising a three dimensional knit in an initial configuration made of knitted polymeric fiber which substantially resumes the initial configuration after it is released from stretching or compressing forces.

[0014] Furthermore, in accordance with embodiments of the present invention, the said evaporation medium substrate has a dimension which changes substantially more than other orthogonal dimensions of the substrate, when subjected to stretching or compressing forces.

[0015] Furthermore, in accordance with embodiments of the present invention, the said device is made of knitted polymeric fiber from material selected from a group of polymer compounds consisting Polyamide, Polyester, Polyurethane, Polyvinyl, Acryl, Polyethylene, Polypropylene, Polycarbonate, PEEK and Polystyrene.

[0016] Furthermore, in accordance with embodiments of the present invention, the said evaporation medium substrate comprises a salt deposition retaining-material

[0017] Furthermore, in accordance with embodiments of the present invention, the said evaporation medium substrate releases salt depositions material from said substrate when stretched.

[0018] Furthermore, in accordance with embodiments of the present invention, the said liquid solution further comprises plurality of dissolved ions.

[0019] Furthermore, in accordance with embodiments of the present invention, the said liquid solution further comprises at least one dissolved inorganic salt material.

[0020] Furthermore, in accordance with embodiments of the present invention, the said liquid solution further comprises at least one dissolved organic salt material.

[0021] Furthermore, in accordance with embodiments of the present invention, the said knitted polymeric fiber evaporation medium substrate is in a drum formation. [0022] Furthermore, in accordance with embodiments of the present invention, the said knitted polymeric fiber evaporation medium substrate is in a flat sheet formation.

[0023] Furthermore, in accordance with embodiments of the present invention, the said knitted polymeric fiber evaporation medium substrate is in a loop band formation.

[0024] Furthermore, in accordance with embodiments of the present invention, wherein stretching of the knitted polymeric fiber evaporation medium substrate is done mechanically.

[0025] Furthermore, in accordance with embodiments of the present invention, wherein stretching of the knitted polymeric fiber evaporation medium substrate is done manually.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to better understand the present invention, and appreciate its practical applications, the following Figures are provided and referenced hereafter. It should be noted that the Figures are given as examples only and in no way limit the scope of the invention. Like components are denoted by like reference numerals.

[0027] Fig. 1 is an isometric illustration of a 3D-knit fabric evaporation medium segment in a relaxed state.

[0028] Fig. 2 is an isometric illustration of a 3D-knit fabric evaporation medium segment in a stretched state.

[0029] Fig. 3 is an isometric illustration of flow-through humidifier-system operated with a 3D-knit fabric evaporation medium 1.

[0030] Fig. 4 is an isometric illustration of a drum system humidifier-system operated with a 3D-knit fabric evaporation medium.

[0031] Fig. 5 is an isometric illustration of a flow through industrial salt production system base on the evaporation of water containing dissolved salts from a 3D knit fabric.

[0032] Fig. 6A is a schematic side view illustration of an industrial salt production system base on the evaporation of water containing dissolved salts from a turning 3D knit fabric belt. [0033] Fig. 6B is cross-cut side view illustration of the mechanism for stretching the turning 3D knit fabric belt, illustrated in Fig. 6A.

[0034] Fig. 6C is an illustration of a view from above of the mechanism for stretching the turning 3D knit fabric belt, illustrated in Fig. 6A.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0035] Embodiments of the present invention describe the use of mono-filament knit fabrics for the use as a liquid evaporation medium having a high ratio of surface-area to volume.

[0036] Liquid evaporation media fabrics in accordance with embodiments of the present invention comprise 3 dimensional knit fabrics (referred from herein after as "3D knits") structured with two faces of knitted loops having connecting filaments between the two faces and filaments intertwined in the space between the two faces. 3D knits been previously described in WO2006033101 (Hascalovich) and PCT/IL 08/00888 (Gavrieli and Hascalovich).

[0037] Both terms "filament" and "fiber" used in the text refer to the thread structure that produces mono-filament knit fabrics and are used interchangeably fromhere in after.

[0038] The 3D knit evaporation medium fabrics are constructed with interlock knitted on alternate knitting needles, where the sequence of the knitting needles defines the distance between the faces of the knit (the width of the structure). The 3D knit is elastic, flexible and resilient, so that when it is subjected to crushing forces it may yield and when relieved from these forces it regains its original configuration. In the context of the present invention, the Y and Z dimensions of the knit indicate the width and length dimensions respectively, "two faces of knitted loops" refers to the two opposite flat-sides of the knit. The X dimension indicates the thickness of the knit (see 25 in Fig. 1 and Fig. 2).

[0039] The present invention refers to the core of the device disclosed in WO2006033101 (Hascalovich) incorporated herein by reference, which describes the use of fibers produced from threads of high stiffness for textile cores and sandwich structures. The 3D textile in the mentioned patent application is preferably produced from anisotropic synthetic materials, which have a long range ordering in one preferred direction over other orthogonal directions. Non-limitative examples of fibers made from such materials include crystalline or semi-crystalline polyamide ("Nylon") 6,6, isotactic polypropylene, and HDPE (High Density Polyethylene), Polyester. Despite the above, it is not to be construed that the present invention is limited in any way only to the use of anisotropically oriented materials for the fabrication of the 3D knit. Preferable construction materials may also be selected from the following list: Polyamide (e.g., PA 6), Polyester (e.g., PCT, PET, PTT), Polyurethane (e.g., PUR, EL, ED), Polyvinyl (e.g., CLF, PUDF, PVDC, PVAC), Acryl (PAN), Polyethylene, Polypropylene, Polycarbonate, Polystyrene. PEEK Carbon, Basalt and similar materials may also be of use.

[0040] In embodiments of the present invention the choice of the mono-filament or multi filament polymers used and the knitting technology of the filaments are such that the produced 3D knit comprises knitted loops that form substantially parallel rows or columns. The" Z-dimension" of the knit refers to the orthogonal dimension in which pulling the edges of the knit in opposite directions would result in substantial separation of the rows of loops with respect to one another ("stretching state" of the knit). The orthogonal direction in which no gaps or only relatively minor gaps are found between the rows of loops upon pulling of the edges is referred to as the "Y-dimension". On stretching the knit in either the Z-dimension or Y-dimension the thickness of the knit, referred to as the orthogonal "X-dimension" diminishes somewhat due to the stretching of the fibers, but the knit remains resilient and regains its original configuration when the pulling forces are stopped ("relaxed state" of the knit). The construction of the knit is illustrated in Fig. 1 and Fig. 2.

[0041] The choice of the type or mode of knitting, typically done by automatic industrial kitting machines, together with the choice of the composition of the filaments, predetermines the compaction of the fibers in the knit, thus the porosity, surface area and the specific weight of the knit can be engineered.

[0042] In another embodiment of the present invention, knit-fabrics are co-knitted with both mono-fibers and multi-filament fibers, in proportions and chemical compositions depending on the engineering of the 3D knit. While the multi-filament fibers aid in reducing the gaps between the filaments of the fabric the mono-filament fibers maintain the stretching and relaxing characteristics of the knits, as previously described. The ratio between the mono-filament fibers and multi-filament fibers determines the resilience of the fabric between the stretched and relaxed state. The larger the ratio in favor of the mono-filaments, the more resilient is the produced fabric. An example of co-knitted fabrics is the use of polyamide ("Nylon") mono-filaments of 0.3 or 0.4 mm thickness co-knitted with filaments made of bundles of polyethylene or polyamide multi-filament fibers, each multi-filament having a diameter of approximately 100 denier and the aggregate of bundles forming a filament of between 0.3 to 0.4 mm. The ratio between the mono-filament fibers and the multi-filament fibers varies from 1:1 to 1 :5. 3D-knit fabrics construction provides for a high ratio of volume to surface-area. Typically, a square meter of fabric produced from mono-filament polyamide fibers of 0.3 mm thickness (weighing between 0.9-1.1 Kg) has an integrated surface area engulfing the filaments of approximately 20 square meters. Depending of the yarn thickness utilized and the knitting density and formation of the fabric, the ratio of volume:surface area may be somewhat higher or lower. In their relaxed state 3D-knits enable almost unhindered passage of air through the X-dimension ("thickness) of the fabrics.

[0043] When a liquid-solution of dissolved ions and cations comes into contact with a fabric of 3D-knit it typically smears on the surface-area of the filaments. When the smeared liquid solution come into contact with ambient air the liquid evaporates causing salt particles to precipitate and deposit on the fibers of the fabric. The precipitation gradually forms deposition-layer locations ("deposition-spots"). As the evaporation proceeds the deposition-spots expand and thicken and in the process connect and bridge together closely positioned fibers in a common deposition-layer mat. As the deposition progresses the available surface area for evaporation on the fibers gradually recedes and the passages through the 3D-knit clog. The clogging limits the free passage of air through the fabric. Unless dealt with, the deposition continues till the 3D knit becomes clogged to an extent that it no longer serves as an efficient evaporation medium. [0044] The contacting process of liquid-solution of dissolved ions and cations with a 3D-knit for the evaporation process described above can be induced in three manners; each manner can be applied separately or in conjunction.

[0045] Submerging and later removing the 3D-knit into and from the liquid-solution of dissolved ions and cations

[0046] Spraying on the 3D-knit a liquid-solution of dissolved ions and cations

[0047] Trickling or spilling into or over the 3D-knit a liquid-solution of dissolved ions and cations.

[0048] The term "submerging" in the text from herein after refers to the three contact manners (separately or in conjunction) of a liquid-solution to a 3D-knit, as described above.

[0049] When stretching a 3D-knit with precipitation depositions from its relaxed state the fibers of the fabric change their relative spatial positions. The change of closely positioned fibers connected by a common deposition-layer mat causes the matrix of the mat to break. In breaking, fragments are released from the matrix of the mat. Following the breaking, a liquid and or gas stream through the now stretched 3D-fabric displaces and removes the fragments from the 3D knit. After removal the solid fragments can be removed or "harvested" from the system in which the 3D-knit is used as an evaporation medium.

[0050] By periodically stretching and relaxing a 3D knit in the course of continuous submerging the 3D knit prior to its becoming fully clogged (when stretching and relaxing may no longer be effective), the fabric can be utilized without the necessity to stop the submerging procedure for cleaning and refreshing the 3D knit.

[0051] In another embodiment of the present invention, stretching of the 3D-knit fabric for refreshing and cleaning is done after removing the knit fabric from the evaporation system, when the 3D-knit is clogged.

[0052] hi the text (accompanying the Figures) given from herein after, examples of the use of the present invention are given by the use of inorganic ions and cations water solutions in contact with 3D-knits. The device of the present invention is not limited to inorganic ions and cations dissolved in water and is applicable as well to organic ions and cations dissolved in organic or inorganic liquid solvents.

[0053] Reference is now made to the Figures to better illustrate the embodiments of the present invention.

[0054] Fig. 1 is an isometric illustration of a 3D-knit fabric evaporation medium 10 segment in a relaxed state. The arrangement of the 3D knit relatively to the axis, as previously explained in the text, is drawn in coordinate-system 25 in the Figure. The illustration shows the two faces of the knit fabric, 12a a 12b, and connecting and intertwined filaments in the space between the two faces. The connecting filaments can be mono-filaments 14 or, alternatively, mono-filaments 14 intertwined together with multi-filaments 16. The 3D knit serves as a water evaporation medium in which a stream of a water solution 18a of dissolved inorganic salts (typically but in no way limited to calcium-carbonate (CaCCβ) and/or magnesium-carbonate (MgCO3)) is trickled into 3D knit 10. The water solution trickle is shown entering the fabric 18a, running through 3D-fabric 10 between the spaces of filaments 14 (or both 14 and 16) and through faces 12a and 12b, designated 18b, and exiting 3D-fabric, designated 18c. The water solution trickles through the entire thickness of the fabric, designated as the "X-dimension", throughout the breadth (horizontal dimension in the Figure) of the fabric, designated "Y-dimension" and trickles downwards along the "Z-dimension" (the vertical dimension in the Figure). As the water solution trickles through it wets the fibers of the fabric with a thin wetting-film. To induce water evaporation air stream 20 is blown through wetted fabric 10, coming into contact with the fabric substantially in perpendicular to face 12a and exiting through face 12b, in the "X-dimension". Air stream 20 blowing into the fabric is designated 20a, when coming out designated 20b. In coming to contact with the wetted surfaces on the filaments some of the water in trickle stream 18b evaporates causing locations of over saturation concentration and salt crystals precipitate and deposit 22 on the filaments. As the trickling of water and the blowing of air continues the salt precipitation covers more and more of the filaments surface areas till eventually filaments are connected together in a joint common mat of precipitated salt crystals. As more filaments connect together the air passage trough the 3D-knit becomes increasingly abstracted and the evaporation of water substantially reduced.

[0055] In another embodiment of the present invention the trickling stream of the dissolved salts water solution (designated 18a in entry, 18b during streaming and 18c on exiting, in Fig.1 and Fig. 2) now enters and trickles along the Y-dimension of 3D knit (which becomes the vertical dimension) and flows throughout the entire thickness of the fabric, designated as the "X-dimension" and throughout the breadth (the horizontal dimension in Figure 1) of the fabric, designated "Z-dimension". The embodiment is illustrated by changing the position of the knit fabric in Fig. 1 by 90° in the Y and Z coordinates of the Figure. In the embodiment, the trickling stream runs along "channeling formations", inline with the substantially parallel rows or columns that form the structure of the fabric. To induce water evaporation, an air stream (designated 20 in Fig. 1) is blown through the wetted fabric coming into contact with the fabric substantially in perpendicular to the two parallel faces of the fabric in the "X-dimension (the air illustrated entering face 12a and exiting through face 12b in Fig. 1). The stretching and relaxing of the 3D knit remains in the Z-dimension, as illustrated in Fig. 2.

[0056] Fig. 2 is an isometric illustration of a 3D-knit fabric evaporation medium 10 segment in a stretched state. The filaments of the fabric in the Fig. were previously coated with a precipitation of salt crystal depositions, forming salts crystal mats, as illustrated in Fig. 1. Upon stretching in the "Z-dimension" filaments 14 (or, in another embodiment, filaments 14 and 16) obtain a different spatial configuration and the common mineral-mats of salt crystals precipitation depositions (22 in Fig. 1) fragment to fragments 24. Trickling water stream 18a enters the 3D-knit, loosens and washes the fragments away from the fibers of the fabric 18b, and away from the 3D-knit 18c.

[0057] hi another embodiment of the present invention, by rapidly and continuously changing the state of the 3D knit from "relaxed" to "stretched" several times and simultaneously increasing the amount of water entering the 3D-fabric 18a, the efficiency of cleaning and refreshing of the 3D knit can be substantially improved in comparison to cleaning and refreshing effect obtained by a single stretching motion and with no water streaming increase. [0058] Fig. 3 is an isometric illustration of flow-through humidifier-system 26 operated with 3D-knit fabric evaporation medium 10. A sheet of 3D knit 10 in a relaxed-state is placed inside support-frame 28 from which it can be removed at will. Frame 28, with fabric 10 inside, is vertically positioned inside of water reservoir 30 containing water 32. A pump 34 drives water 32 from container 30 through tube 36 to a manifold tube 38, the manifold having openings facing down towards container 30. To each of the openings a tube 40 is connected and runs through the upper part of frame 28, terminating at the upper edge of 3D knitlO inside frame 28. Water containing dissolved salts 32 is pumped from container 30 and is distributed by manifold 38 to tubes 40 and trickles vertically downwards on 3D knit 10. Water 32 trickles along and in between the filaments of the fabric, as described in Fig. 1 (the stream of trickling water is designated 32a). On completion of the trickling course through fabric 10 water 32 returns to reservoir 30 to be re-circulated. Perpendicular to 3D knit 10, fan 42 driven by motor 44, blows ambient air (designated 46) into and through the "depth" (the "X dimension" described in Fig. 1) of 3D knit 10. When air stream 46 encounters trickling water stream 32a it evaporates some of the water, thus raising the dissolved salts concentration in the remaining water and induces salts precipitation on the filaments of the fabric, as was described in Fig. 1. The rate and amount of precipitation depend of the initial concentration of dissolved salts in water 32, on the trickling rate of the water 32a, the rate of air blown 46, as well as on the initial moisture in the air and the water and air temperature. When 3D-knit-fabric becomes clogged, as described in Fig. 1, it is refreshed and cleaned by being removed from frame 28 and stretched under running water, as described in Fig. 2.

[0059] Fig. 4 is an isometric illustration of a "drum system" humidifier-system 46 operated with 3D-knit fabric evaporation medium 10 rolled into a drum-formation 48. System 46 comprises a water-tight reservoir box 60 for water 62 storage and cover lid 64. Cover-lid 64 and water reservoir 60 are connected to plate 68 which is rigidly fixed to a flat surface, typically a wall of a building. Plate 68 has an opening 69 that leads to an air ventilation channel, typically streaming air to a room in a building where system 46 is placed. Two vertical walls, 70 and 72, rise from water reservoir 60 perpendicularly to plate 68 and, together with lid cover 64, engulf in a closed box drum-formation 48. Cover lid 64 is connected by hinges 66 to plates 70 and 72. Drum 48 comprises of a porous cylinder support -frame (not shown) fully covered by 3D knit 10. Drum 48 is connected and capped at its edges by circular plates, 54 and 56. Plate 56 comprises a ring that enables free passage of air. Plate 54 is not connected to drum 48 and is pressed to the edge of the drum by spring 53. Axis-bar 50 runs trough the opening in wall 72, through the center of circular plate 56, along and through the center of drum 48 and to and through circular plate 54. The axis continues through wall 70 and reaches electric motor 52. Spokes support axis 50 in the opening in wall 72, in the ring formation in plate 56 (both support structures not shown). Pivots in walls 72 and 70 enable axis 50 to rotate. Motor 52 rotates axis 50 and by so turns drum 48. Along axis-bar 50 in drum 48 is a telescopic connection (not shown) that enables the lengthening and shortening the length of the axis-bar. Cover lid 64, water reservoir 60, walls 70 and 72, plate 68 and drum formation 48 are made of a rigid material such as plastic or metal. An air duct 74 from the ventilation system of the structure in which system 46 is placed, leads to an opening (not shown) in vertical wall 72. Typically, the air blown through duct 74 originates from a central climate-control blower. Air blows from duct 74 through wall 72, through plate 56 and into drum 48. Drum 48 is positioned so that its lower portion is submerged in water 62 in water reservoir 60. Water is place and removed from water reservoir through tube 73.

[0060] Motor 52, in addition to rotating drum 48, at will and by command, pulls axis- bar 50 towards the motor. In pulling the axis-bar, the length of the bar is extended (by the opening of the telescopic connection) and disk 54 which is connected to the axis is separated from drum 48. The increased distance between the disks 56 and 54 stretches 3D-knit 10 on drum 48, as described in Fig. 2. Spring 53 which is wrapped around axis 50, pushes disk 54 to its original position when the pulling force of motor 52 is terminated.

[0061] In operating system 46 drum 48 rotates, continuously causing a section of the drum to enter while another section to exit water 62 in reservoirs 60. In the section of drum 48 that leave the water droplets from water 60 are "captured" (wicked) in the cavities between the fibers that comprise 3D knit 10. While drum 48 rotates air is blown through duct 74 and reaches disk 54 in the drum. The disk blocks the air flow and the air escapes the drum sideway, through the 3D knit. In passing through the fabric the air vaporizes the droplets, thus discharging moistened air through opening 69 into the surrounding. When water 62 contains dissolved inorganic salts, typically calcium- carbonate (CaCO3) and/or magnesium-carbonate (MgCO3), is evaporated from 3D-knit 10 the concentrations of dissolved salts in water 62 gradually increases and mineral salts precipitation depositions progressively coat the fibers of fabric 10, as described in Fig. 1.

[0062] When drum 48 is coated to an extent that the air flow is substantially hindered motor 52 is commanded to stretch 3D knit 10, thus causing the salts depositions to flake and be removed from 3D-knit 10, as illustrated in Fig. 2. By repeating the stretching- relaxing motions and by simultaneously rotating drum 48 the removal efficiency of the salts coating can be substantially improved. The removed salts crystal mat-fragments drop to water 62 and can be removed from system 46 by replacing the water through tube 73. By stretching and relaxing drum 48 the 3D knit in system 46 can be maintained in an operating condition without the necessity to stop the system for cleaning and refreshing. The stretching-relaxing motion of motor 52 can be computer-controlled enabling an automatic cleaning and refreshing mode for facilities simultaneously operating a large number of humidifier-systems.

[0063] Alternatively, drum 48 can be removed from system 46 for cleaning and refreshing by opening lid 64 and releasing the connections of axis 50 to the drum.

[0064] Fig. 5 is an isometric illustration of a "flow through" industrial salt production system 76 base on the evaporation of water containing dissolved salts from a 3D-knit. The system comprises a flat sheet 3D-knit sheet 10 fastened to stretching-cylinders 80 at both its edges by wires 82. Stretching-cylinders 80 rotated by an electrical motor 84. Stretching-cylinders 80 are connected to a support-frame 86 that maintains 3D-knit in a vertical position relative to the ground. The top of support-frame 86 is connected to a manifold water-distributor 88 that receives the source-dissolved-salts water solution via pump 89 and tube 90 and distributes the water to the 3D-knit (water trickling, designated 92). Alternatively, the dissolved salts water solution can be sprayed on the 3D-knit by a spraying mechanism 94 (sprayed water designated 93). Spraying and trickling can be utilized simultaneously. The water that runs trough the 3D-knit 10 is collected in sink 96 that drains the water either for discharging or for recycling and evaporated. Collection-box 97 slides on rails 98 and is used for collecting dry fragments of the crystal salt mats removed from 3D-knit 10.

[0065] In operating system 76, the source-dissolved-salts-water-solution is trickled or sprayed on the 3d-knit. Ambient air and the sun radiation (when system 76 is located outdoors) evaporate the water causing crystal salt precipitation depositions to accumulate on the filaments of 3D-knit 10 in mat formations, as described in Fig. 1. When the streaming of the water is halted the mat formations dry and harden. When rotating the two stretching-cylinders 80 in opposite directions the 3D-knit stretches, causing the crystal salt mat formations to fragment and the fragments to fall (as described in Fig. 2) into sink 97 from where they are removed manually or by a removing mechanism such as a conveyor belt. On rotating the stretching-cylinders 80 to their pre-stretching position the 3D-knit is again in a relaxed state, ready to be reloaded with salt crystal mats precipitations.

[0066] Fig. 6A is a schematic side view illustration of an industrial salt production system 101 base on the evaporation of water containing dissolved salts from a turning 3D knit 10. The system comprises a 3D knit band in a conveyor (loop) belt configuration, designated 11. Conveyor belt 11 turns in the direction indicated by the arrow designated 15 and is kept in position between four turning wheels: 100, 102, 104 and 106. The motor or motors driving turning conveyer belt is connected to one or more of the four wheels. In the course of turning conveyor belt 11 enters a reservoir of a source-dissolved-salts- water-solution 108, shown in the segment between wheels 106 and 104. The conveyor belt exits water reservoir 108 vertically, shown in the segment between wheels 104 and 102, and is showered by a shower-mechanism 110 that sprayers water from reservoir 108. The shower-mechanism is operated by pump 111. The water soaked belt continues to turn and is positioned horizontally between wheels 102 and 100. Between wheels 102 and 100 belt 11 is supported by support-conveyor- belt 112. In the course of the horizontal movement excess water drips from belt 11 and the ambient air and the sun radiation (when system 101 is located outdoors) evaporate the rest of the water causing crystal salt precipitation depositions to accumulate on the filaments of 3D-knit 10 of belt 11 in mat formations, as described in Fig. 1. Between wheels 100 and 106 the now dried (or almost dried) conveyor belt 11 is stretched by the mechanism described in Fig. 6B and 6C (designated 116 in the Figure) and is scrubbed by rotating brush 114. The stretching, together with the brushing, causes the crystal salt mat formations that formed on the dray conveyor belt to fragment and the fragments to fall into sink 117 (as described in Fig. 2) from where they are removed manually or by a removing mechanism such as a conveyor belt.

[0067] Fig. 6B illustrates a cross-cut side-view of mechanism 116 that stretches belt 11 when positioned opposite brush 114, as shown in Fig. 6 A. 3D knit 10 from which belt 11 in made of, has each of its side margins 1OA engulfed and fastened to a "holder- mechanism" 118. Holder-mechanism 118 connects 1OA to a ground-directed protruding T-shaped bar 120. Bar 120 fits and slides 10a without "escaping" along a predetermined path in a groove 122. Groove 122 is formed by the gap between two plates 124a and 124b; bridged between them by curved bars 126.

[0068] Fig. 6C illustrates a view from above of a single "holder-mechanism" unit 116, shown in Fig. 6 A. Holder-mechanism 116 comprises two units, positioned on both sides of belt 11. The figure illustrates the pre-determined curved path of sliding of T-shape bars 120 (illustrated in Fig. 6B) along groove 122, formed in the gap between plates 124a and 124b, as explained in Fig. 6B.

[0069] In operating industrial salt production system 101 (illustrated in Fig. 6A), in the course of turning each segment of conveyer belt 11 (made of 3D-knit, designated 10) proceeds from wheel 100 to holder-mechanism 116. When advancing through holder- mechanism 116 T-shaped bars 120 enter grooves 116 on both sides of belt 11. The predetermined path along grooves 122 cause belt 11, that till now was in a relaxed-state (shown in Fig. 1), to change to stretch state (as illustrated in Fig. 2). The stretching of belt 11 is done so as to enable rotating brush 114 (illustrated in Fig. 6A) to remove fragmented crystal salt mat fragments from the evaporation medium 3D knit and be collected by sink 117.

[0070] It should be clear that the description of the embodiments and attached Figures set forth in this specification serves only for a better understanding of the invention, without limiting its scope. [0071] It should also be clear that a person skilled in the art, after reading the present specification could make adjustments or amendments to the attached Figures and above described embodiments that would still be covered by the present invention.