WO2012007827A1

WO2012007827A1 - Foam glass manufacturing and applications

Info

Publication number: WO2012007827A1
Application number: PCT/IB2011/001634
Authority: WO
Inventors: Ori Yekutiel
Original assignee: Ori Yekutiel
Priority date: 2010-07-13
Filing date: 2011-07-13
Publication date: 2012-01-19

Abstract

Foam glass article is disclosed, comprising an integral ceramic wall integrated to a foam glass portion. A manufacturing process of said foam glass articles is also disclosed, comprising (i) providing a mold having at least one wall portion made of rigid ceramic material; (ii) providing a predetermined dose of mixture comprising glass powder, foaming agent, and thermal expansion decreasing agent; (iii) heating the mold until the dose of mixture is foamed to a desired volume, said foamed volume thus brought into contact with the at least one ceramic wall portion of the mold; (iv) cooling the mold and the foam; thereby converting the at least one ceramic wall portion of the mold to becoming an integral member of the process product, thus providing a foam glass article having at least one integral ceramic outer wall.

Description

FOAM GLASS MANUFACTURING AND APPLICATIONS Field of the invention

The invention is in the field of foam glass manufacturing and applications.

Background of the invention

Constantly increasing demands in the global markets for environmental friendly products, especially recycled ones, have led to ever growing market of foam glass products. It is accordingly expected that recycled glass will be utilized for a broad variety of product types. Unfortunately, most recycled glass returns to the global markets as hidden non-styled products.

Foam glass products are commonly provided as blocks sawn from a greater pellet. The products are for use as a filling material, a substrate to be covered by exterior surfaces, isolating material partitioning between double sided walls and the like. They are accordingly hidden from end user's eye and are thus of insignificant value in terms of decoration and ornamental design. As an isolating material they are most commonly to be sealed for fluids, thus provided with substantially uniform closed foam cells.

It is therefore an object of the present invention to provide methods which will allow for producing more stylized foam glass articles. This is not so simple in view of the fact that foam glass can difficultly be shaped by molding. Foam silica tends to inseparably integrate with the mold. In order to allow for demolding, foam glass molds are typically made of heatproof steel coated by kaolin. The outer surface of a product released from kaolin coated molds contains unfinished outer surfaces comprising a solid mixture of foam and kaolin residuals. WO 06/059306 and WO 94/014714 are examples of publications suggesting uses of foam glass in decoration, or offering use of foam glass for producing shaped articles.

Alternative manufacturing methods and proposed foam glass articles will be disclosed herein after, and are aimed at broadening the availability and collection of styled foam glass articles as well as their participation in environmental friendly constructions, architectural designs, and general decoration.

Summary of the invention

In a first broad aspect the invention relates to manufacturing process of foam glass articles, the product of the process is obtainable by (i) providing a mold comprising at least one wall portion made of rigid ceramic material; (ii) providing a predetermined dose of mixture comprising glass powder, foaming agent, and thermal expansion decreasing agent; (iii) heating the mold until the dose of mixture is foamed to a desired volume, said foamed volume thus brought into contact with the at least one ceramic wall portion of the mold; (iv) cooling the mold and the foam; thereby converting the at least one ceramic wall portion of the mold to becoming an integral member of the process product, thus providing a foam glass article having at least one integral ceramic outer wall.

According to various preferred embodiments of the invention the heat expansion decreasing agent comprises lithium.

The relative amount of the heat expansion decreasing agent contained in the mixture is adapted to reduce the thermal expansion coefficient of the foam for substantially matching the expansion coefficient of the ceramic material.

The invention further relates to a glass article comprising an integral ceramic wall integrated to the foam by the aforementioned process.

In various embodiments of the article the ceramic wall is in the form of a receptacle, and the foam glass constitutes a core portion integral to the receptacle.

In yet further embodiments of the invention the ceramic wall is in the form of a sleeve, and the foam glass constitutes a core portion integral to the interior surface of the ceramic wall.

A plurality of articles having substantially identical cross section may be sliced from each longitudinal sleeve like article. According to some embodiments the foam glass article comprises integral ceramic double wall (i.e. two walls with a gap in between) integrated to the foam from opposite sides (i.e. each of the two walls constituting the double wall is located opposite to the other, with the foam in between) by the aforementioned process.

At least one of a first and a second walls constituting the double wall may be formed and be used as a receptacle.

In various embodiments of the invention the foam is mainly of closed cells.

In yet other various embodiments of the invention the foam is mainly of open cells.

In various embodiments having foam of open sells, at least a portion of the open cells are communicated by cavities.

In another broad aspect the invention relates to a combination between a foam glass article and a living plant.

In said combination, the foam comprises open cells, at least a portion of said open cells are communicated by cavities, wherein roots of the plant are extending into open cells and through cavities communicating between foam cells.

According to various embodiments of the invention the foam glass article comprises open cells and cavities communicating between at least part of the open cells, the article further comprises dehydrated nutrients or chemicals for enhancing plant growth.

Detailed description of the invention

In a first broad aspect the invention relate to a manufacturing process of foam glass articles, the product of the process is obtainable by (i) providing a mold comprising at least one wall portion made of rigid ceramic material (e.g. hardened clay); (ii) providing a predetermined dose of mixture comprising glass powder, foaming agent, and thermal expansion decreasing agent; (iii) heating the mold until the dose of mixture is foamed to a desired volume, said foamed volume thus brought into contact with the at least one ceramic wall portion of the mold; (iv) cooling the mold and the foam for annealing; thereby converting the at least one ceramic wall portion of the mold to become an integral member of the product and providing a foam glass article having at least one integral ceramic outer wall.

Said thermal expansion decreasing agent is provided in order to allow for safe annealing of the foam glass and its successful integration with the ceramic wall without producing thermal stresses and cracking which are normally expected due to a greater thermal expansion coefficient of foam glass comparing to that of ceramics. The amount of the thermal expansion decreasing agent (e.g. lithium powder or any other acceptable thermal expansion decreasing agent) in the mixture is determined (based on experience) to provide the foam with thermal coefficient of expansion similar to that of the ceramic material thereby allowing for a correlated contraction of the mold and the foam during cooling, thus avoiding thermal stresses and foam cracking.

In various preferred embodiments of the invention the glass powder portion of the mixture comprises between 15% and 40% by weight of basalt powder. The basalt powder may be obtained by grinding basalt stone of natural origin.

In the context of the present invention, the term "glass powder" refers also to glass powder comprising pigments.

The ceramic mold according to the invention may have any desired wall thickness which can practically be handled, and is to be determined as a matter of design in consideration of the intended use of the product and its accordingly preferred strength to weight ratio.

As can be appreciated, the ceramic wall portion of the mold is for single use, since it becomes an integral member of the process product. Accordingly, a plurality of identical ceramic molds (or ceramic wall portions of a mold) should be prepared in advance, according to the number of articles to be prepared.

In the heating step the mold and its content are normally subjected to temperatures of between 800 - 1,000 Celsius, depending on the properties of the glass powder mixture to be foamed. It can be anticipated that high temperatures may be required in special cases or for special products. It is thus to be noted that higher temperatures up to 1 ,800 C or even more may be acceptable, without departing from the scope of the present invention.

According to various embodiments of the invention the integrated article obtainable by the process is a tile for use in the building industry, the outer ceramic surface of the article is ornamentally designed as a conventional ceramic tile to be exhibited and utilized as an exposed wall covering, and its foam glass portion is for increasing the thickness of the tile and for improving the thermal and/or other isolation properties of the tile, without significantly increasing its weight. The manufacturing process may further comprise sawing a plurality of integrated tiles from an integrated pellet of a greater size. The integrated pellet may be manufactured to have a thicker layer of foam glass than required for the integrated article, thereby allowing external portions of the foam glass remote from the ceramic portion to be sawn and separated from the pellet free of ceramic wall portions, for use as conventional foam glass tiles. Accordingly, a portion of a manufactured pellet according to the invention may be utilized to produce conventional foam glass tiles, while other portions thereof are utilized as integrated product comprising ceramic tile having integral foam glass back portion.

The exposed facets of a slice of a foam glass plate sawn from the pellet may be combined with a glass plate to form a two layer plate having a foam glass surface on one side and a conventional glass surface on the opposite side, useful as a decorative wall plate which can be utilized, e.g. for shading, according to its light and/or other radiation screening properties. The screening and shading capabilities of the combined plate can be adapted to the intended use by increasing or decreasing the thickness of the sawn foam glass plate portion of the combination. Moreover, a foam glass plate sliced from the pellet may be sandwiched between two conventional glass plates to form a double glass window semi permeable to light. The thickness of the foam glass plate can be determined according to the intended use, thus can be mounted in a conventional window frame configured to receive a conventional double glass window pane having an air gap in between the glasses, with the foam glass plate located within said air gap.

In yet additional embodiments of the invention a conventional glass plate may be integrated with the plate of foam glass sliced from the pellet. This can be accomplished by placing the glass plate on a slice of the foam glass (or on the foam glass face of the product, opposite the ceramic face, and by inserting both into a heated furnace such that the conventional glass plate "falls" onto the foam glass, and becomes integrated with it while tracing its unique topography. Expertise and experience are required in accounting for the thermal coefficients of the involved materials, in order to successfully accomplish this integration and its consequent cooling processes. The invention further relate to embodiments in which open vesicles of the sawn surface of the foam glass are filled by glass powder, and the product is then conveyed into a heated furnace in order to provide for a smooth outer surface. Alternatively, hot glass can be poured on the open vesicles of the sawn surface, for the same purpose.

According to the invention, the mold for producing the invented tiles may comprise a flat bottom ceramic plate over which a glass powder mixture for foaming may be evenly distributed so as to provide for substantially even foam glass layer to be created on the bottom plate upon heating. The mold structure may be accomplished by providing separable side walls (e.g. made of kaolin plated steel), or by providing ceramic side walls either in one piece with the ceramic bottom plate or in separate plate sections encompassing the bottom plate and pressed towards its edges in order to avoid leakage of foam off the ceramic bottom plate. Alternatively, the ceramic base plate constituting the at least one wall portion of the mold according to the present invention, may be positioned within an external kaolin coated conventional mold having side walls for barring lateral leakage of the foam off the ceramic base plate.

It should be noted, that the ceramic base plate is not necessarily flat, and may have a contour according to the desired contour of specific intended product. . The upper surface of the mold (according to either of said alternatives) can remain open. Alternatively, a second ceramic plate (similar in dimensions to the first, bottom, plate) may be provided as a cover to be integrated with the foam upon heating thereby providing for a double wall ceramic article having a foam glass core. The double wall ceramic article may then be used as is, or alternatively be sawn into ceramic double wall tiles having foam glass core, which in turn may or may not be sawn and separated into single ceramic wall tiles having integral foam glass layer. According to various embodiments of the invention the entire mold is made of ceramic material, and is shaped as an open receptacle. The integrated product thus comprises a bottom wall and a surrounding wall integral with a foam glass core. The process may further comprise a step of providing a pit or a vertically oriented bore in the foam glass core of the receptacle, for receiving and holding an ornamental object. The pit or the bore may be produced post annealing e.g. by grinding or drilling. They can alternatively may be produced during the foaming process, e.g. by positioning a retractable kaolin plated steel insert or piston preventing the foam from occupying the space intended for the pit or bore, and by retracting the insert from the foam upon solidification.

It is well known that foam glass may be of open cells or of closed cells. The nature of the foam cells may be determined by appropriate selection of the ingredients of the glass powder mixture to be foamed and in some cases may be subjected to some further production steps to be taken. For example, US 20080286555, incorporating by reference US 3,945,816 indicates and differentiates between such processes. Accordingly, the integrated product according to the invention may comprise a foam glass core of either closed cells or opened cells, or combinations thereof, based on the glass powder mixtures used for foaming, their homogeneity, their distribution in the mold before heating, and based on any other production steps which may affect the nature and structure of the foam cells.

A flower vase may accordingly be produced by a process according to the present invention, said vase comprises closed cells foam glass core with a bore for receiving e.g. a lower end of flower stems, as well as a small amount of water, said foam glass core is integrated within a ceramic receptacle utilized as a mold for shaping the foam. A planter may also be produced by a process according to the present invention, said planter having foam glass core of open cells, is integrated within a ceramic receptacle utilized as a mold for shaping the foam during its production. At least one pit or a bore for receiving e.g. a lower end of plant stems or trunk may be provided in case the planter is intended for plants having trunk or stems. In case the planter is for use for growing herbs or weeds the foam glass core may be provided with a planer top. The planter according to the invention may be provided with at least one bottom aperture for draining excess water. The open cells nature of the foam glass core of the planter is advantageous for live plants in several aspects: (i) it allows root of plants to extend into open cells and to spread through internal cavities connecting between the cells; (ii) it allows for distributing fertilizers and small amount of soils throughout the core, either in advance of or after planting, wherein the fertilizer and/or soil are accommodated and maintained within tiny pits and pores naturally presented as a part of the foam structure; (iii) it allows for watering the planters with small amounts of water taking advantage of the porosity of the foam acting as a wick and distributing moisture and dissolved nutrients throughout the entire core by means of capillary tension; (iv) since the foam is substantially airy rot of plant roots due to excess moisture conditions is minimized; (v) planter weight is substantially smaller comparing to conventional soil filled planters thereby easing mobility of planters, facilitating their removal from sunny to shadowed areas or vice versa.

The above mentioned advantages of open cells foam glass for plants may be improved and adapted for different type of plants by optimizing the porosity of the foam, the average ratio between open and closed cells, the average size of cells, and the distribution of cell sizes, to particular growth requirements which may be associated with different plant types.

It is appreciated that when a ceramic receptacle is used as the mold in the invented process, the dose of glass powder mixture to be used may be determined as a matter of design to provide for a foam glass core of a desired volume and height within the receptacle, which may or may not entirely fill the receptacle. It is also appreciated that the receptacle wall may not necessarily be designed to have an even top.

In another broad aspect the invention relates to a combination of open cells foam glass and living plants, the combination comprises a foam glass substrate and at least one living plant, wherein said plant is positioned on and supported by the foam substrate such that roots of said at least one living plant are capable of growing and extending into open cells of the foam glass substrate and of spreading through cavities in the foam communicating between at leas part of the open cells. It can be appreciated that further to the advantages of open cells foam glass substrate in terms of plant growth, at least part of which are mentioned above, the plant and foam glass combination is advantageous in terms of architectural design as well. As mentioned in the background of the invention, foam glass is commonly used as a filling and thermal isolating means in the construction, infrastructure and building industry, hidden from the eye of everyday passerby or inhabitants. This can be changed by implementing the living plant and foam glass combination of the present invention. For example, according to this aspect of the invention, foam glass tiles configured to be combined with living plants may be used for covering exterior walls or selected portions of exterior walls, surrounding walls of gardens and parks, infrastructure walls and the like. They may also be used ornamentally in substitution of selected tiles surfacing interior walls. Optionally, when used as internal thermal insulation of walls, selected portions of the wall covering may be omitted, thereby exposing foam glass portions located inside the wall for use as a substrate for plant growth.

Preferably, in order to furthermore improve the appearance of the exposed foam glass, and in order to form a more natural and environmental friendly look of the material, means can be taken to provide it with a pumice , scoria, or natural lava like appearance (e.g. by mixing the glass powder with pigmenting substances, and increase the distribution and randomness of cell sizes and shapes within a given pellet of foam glass). Furthermore, the foam glass pellets or tiles may be treated in advance to improve and facilitate plant growth, e.g. by dipping into nutrient solutions followed by dehydration or e.g. by spraying them with such solutions, fertilizers or any useful chemicals.

The production process according to the invention may further comprise a step or steps of positioning predetermined elements in the ceramic mold, to be integrated with the foam glass core during foaming. These elements may be, for example, spacers allowing for positioning a floating ceramic part of the mold, e.g. in case a double walled article is desired and a top ceramic piece is to be positioned a predetermined gap from above the bottom plate. In other cases these elements may be a piece or pieces of natural pumice or scoria to be presented on a bottom of a ceramic receptacle or on a layer of glass powder mixture presented on said bottom, in order to increase the weight and lower the center of gravity of a planter to be created by the process, thereby improving its stability. The piece thus presented will be integrated with the foam glass core, upon foaming. It may be appreciated that floating mold members may not necessarily utilize in-mold spacers for positioning, and may alternatively be either supported upon side wall portions of the mold, or suspended from above, or supported upon out of mold spacers. In various embodiments of the invention the ceramic mold may be in the form of elongated open ended sleeve, which as a matter of design may have any desired cross section, e.g. circular, oval, rectangular, or other, and may be of any desired length which can be handled. The glass powder mixture to be foamed may be provided and distributed in advance along the interiors of the sleeve length, or alternatively be continually poured into the sleeve during a continuous manufacturing process in which the ceramic sleeve is conveyed through a furnace and the glass powder mixture is poured continually into sleeve portions advancing towards the furnace entrance through appropriate nozzle entering it through its open back end.

In various preferred embodiments the amount of glass powder presented into the sleeve is determined to exactly fill the sleeve upon foaming. After annealing, the ceramic sleeve and the foam glass core integrated to its interior wall may be sawn to a plurality of slices of a desired length.

In a first embodiment the slices thus produced may be used as foam glass tiles having a surrounding integral ceramic borders, to be bonded to corresponding adjacent ceramic borders of other tiles thereby providing a wall surface of special ornamental design exhibiting a plurality of foam glass cores bordered by their integral individual ceramic frames.

In other embodiments the slices may be used as planters, having the foam glass core exposed as respective bottom and top surfaces thereof. In yet additional embodiment the slices may be used as heat isolating plate e.g. for use in a kitchen as a footing for cooking pots.

Other kitchen articles may be produced as well using the method of the present invention. These include but not limited to ceramic double walled bowls or cooking pots comprising foam glass core as a heat insulating material integral to the outer bottom of a top ceramic receptacle configure to receive food (and which is utilized as a top cover of the ceramic mold for the foam during its production process according to the invention), and to a bottom plate (or receptacle) to be exposed to a heat source in the kitchen (and which is utilized as a bottom plate of the ceramic mold during the foaming process). The cooking pot or bowl thus produced may be useful e.g. for slow cooking procedure, for heating food, or for temperature maintaining.

The ceramic mold, in its role as an integral outer wall in the various articles produced according to the invention may be, painted, finished, glazed, or otherwise treated by any acceptable process known for finishing ceramic articles.

A glazing process for finishing may be carried out according to the invention either during the first heating and foaming process, or in a finalizing step taken post annealing, and involving a second heating step.

When the glazing process of a ceramic surface of the invented product is taken post annealing, a very thin slice of the foam glass which has been sawn from the product face opposite to the ceramic surface (having a web like appearance due to its small thickness), may be positioned on the ceramic surface, with or without glazing powder in between, such that when burning the product for glazing, the thin slice is melted on the ceramic surface, coating it with an innovative decorative (somewhat 3D) texture, resulting from the web like form of the thin plate, on the ceramic wall surface.

It is also possible according to the invention to treat the foam glass facets of the product by glazing, e.g. by conveying the foamed glass product rapidly through a super heated furnace, such that only its exteriors will be melted, without damaging the stability of the interiors of the product.

The invented product may also be finished by compounded materials such as epoxy and polyester (preferably transparent or semi transparent) to be applied on the foam glass facets of the invented product providing them with smooth rigid surfaces while maintaining their unique basic appearance.

The invention further relate to an integration step between the invented product and metal elements, according which at least one metal element, such as a pipe is placed in a desired orientation within the mold before the foaming step, such that the final product comprises said pipe (or any other desired metal element/s) embedded as an integral part thereof. In various preferred embodiments of the invention the metal elements may be mutually connectible connectors, allowing for connecting a plurality of pieces of the final product by means of said connectors to form a desired construction. A plurality of metal elements embedded in a single product may be interconnected by a metal grid allowing the foaming mixture to expand through, such that the grid becomes embedded as well as an integral part of the final foam glass article.

Claims

1. Manufacturing process of foam glass articles, the product of the process is obtainable by (i) providing a mold comprising at least one wall portion made of rigid ceramic material; (ii) providing a predetermined dose of mixture comprising glass powder, foaming agent, and thermal expansion decreasing agent; (iii) heating the mold until the dose of mixture is foamed to a desired volume, said foamed volume thus brought into contact with the at least one ceramic wall portion of the mold; (iv) cooling the mold and the foam; thereby converting the at least one ceramic wall portion of the mold to becoming an integral member of the process product, thus providing a foam glass article having at least one integral ceramic outer wall.

2. The method according to claim 1, wherein the heat expansion decreasing agent comprises lithium.

3. . The method according to claim 1, wherein the amount of the heat expansion decreasing agent contained in the mixture is adapted to reduce the thermal expansion coefficient of the foam to substantially match the expansion coefficient of the ceramic material.

4. Foam glass article comprising an integral ceramic wall integrated to the foam by the process of claim 1.

5. Foam glass article according to claim 4, wherein the ceramic wall is in the form of a receptacle, and the foam glass constitutes a core portion integral to the receptacle.

6. Foam glass article according to claim 4, wherein the ceramic wall is in the form of a sleeve, and the foam glass constitutes a core portion integral to the interior surface of the wall.

7. Foam glass article sliced from an article according to claim 6.

8. Foam glass article according to anyone of the preceding claims, wherein the foam is mainly of closed cells.

9. Foam glass article according to anyone of claims 4-7, wherein the foam is mainly of open cells.

10. Foam glass article according to anyone of claims 4-7, wherein the foam is mainly of open cells, at least a portion thereof are communicated by cavities.

1 1. Combination of foam glass article and a living plant.

12. Combination of foam glass article and a living plant wherein the foam comprises open cells, at least a portion of said open cells are communicated by cavities, and wherein roots of the plant are extending into open cells and through cavities communicating between foam cells.

13. Foam glass article comprising open cells and cavities communicating between at least part of the open cells, further comprising dehydrated nutrients or chemicals for enhancing plant growth.

14. Foam glass article comprising integral ceramic double wall integrated to the foam from opposite sides by the process of claim 1.

15. Foam glass article comprising integral ceramic double wall according to claim 14, wherein one of a first and a second walls constituting the double wall is formed as a receptacle.

16. The method according to anyone of claims 1 - 3, wherein the glass powder comprises basalt powder.

17. The method of claim 16, wherein the basalt powder weighs between 15% and 40% of the glass powder.

18. The method according to anyone of claims 1 - 3 and 16-17, further comprising slicing a thin plate from the annealed foam glass, placing it on an exterior surface of the ceramic wall, and heating both until the sliced plate is melted on the ceramic wall surface, thereby providing for a glass coating of a texture resulting from the web like form of the thin plate, on the ceramic wall surface.

19. Foam glass article according to anyone of claims 4 - 10 wherein the foam glass comprises natural basalt ingredients.

20. Foam glass article according to anyone of claims 4 - 10, wherein an exterior surface of the ceramic wall comprises a foam glass texture formed of a melted slice of the a foam glass.