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(11) | EP 0 255 795 A2 |
(12) | EUROPEAN PATENT APPLICATION |
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(54) | Method for cutting stone or stone-like blocks into large and thin slabs, and their reinforcement |
(57) This invention aims to the production of new products from decorative rocks, that
will be free from two serious disadvantages of the natural products, the great specific
weight and the low flexural strength, also much improving the economical result of
the production, because the rendering of the marble blocks-granite blocks is over
the double. The new products will be large slabs or also thin (5- 7 mm) tiles (module marble and module granite), that will be covered and reinforced on one face with substances giving them increased strengths, a decreased water absorption and a safe anchorage to the building elements. More particularly, this invention solves mainly the problems of cutting of the decorative rocks (marbles* and granites**) into very thin slabs (5- 7 mm). The method of this invention has nothing common which that used to the produc- tionof thin tiles, measuring 15 x 30 x 0.7 cm .as it refers to the possibility of production of large and thin slabs (e.g. 155 x 320 x 0.5 cm). * marbles are crystalline or granular compact rocks, consisting of minerals with ahardness of 3-4 of the Mosh scale (calaite, dolomite, serpentine), that can be cut, grid and polished, used as decorative and building materials. * * granites are phanerocrystalline compact rocks, consisting of minerals with hardness 6-7 of the Mosh scale (quartz, feldspar, feld- spathodis) that can be cut, grid and polished, used as decorative and building materials. Furthermore, this invention solves the problem of the reinforcement of slabs with resin glass-fibers or also resin glass-clothes, which, as they are hydrophobe materials, the slabs should be completely free from dampness. The additional increase of the inflexibility of the slabs was achieved by the use of enlarging materials (e.g. polyurethane). The self-anchorage of the slabs is realized by depositing of gravel to the still fresh surface of the resin glass-cloth. The reinforced slabs produced within the frame of this invention are much more lighter (16-20 kg/m2), in comparison with the natural slabs 2 cm thick (55 kg/m2) and they can be much longer without being broken. Finally it should be noted that each square meter of reinforced slabs is charged totally with the sum of US $ 6.00 (prices of 1986), which sum is covered by the over than the double rendering (from 1 m3 of marble-block or granite-block the theoretical production is 40 m2 of slabs, 2 cm thick or more than 83.3 m2 of reinforced slabs 0.5 ÷ 0.7 cm thick). |
CUTTING OF MARBLE BLOCKS-GRANITE BLOCKS IN THIN SLABS
1. Cutting with frame machine
1.1. Description of the sawing
1.2. Rendering of the method
2. Cutting with blocks sawing
2.1. Description of the cutting
2.2. Rendering of the method
CHAPTER TWO
REINFORCEMENT OF THE SLABS, THEORETICAL AND EXPERIMENTAL DATA
1. Max. stress of natural slabs
1.1. Slab measuring 1=320 cm, b=155 cm, h=0,5 cm
1.2. Slab measuring 1=320 cm, b=155 cm, h=0,7 cm
2. Flexural strength of natural slabs
2.1. Specimen of cipollinic marble measuring 1=14 cm, b=5,63 cm, h=0,52 cm
2.2. Specimen of white Pentelic marble measuring 1=14cm, b=7cm, h=0,7cm
3. "Flexural Strengths"of reinforced slabs
3.1.Reinforced slabs of cipollinic marble, thick 0,62÷0,68 cm
3.1.1. Marble specimen reinforced with fine-woven glass-cloth (Bε = 50 gr/m2), measuring 1= l4cm, b = 5,63cm, h1 = 0,62cm (h' = 0,55cm).
3.1.2. Marble specimen reinforced with resin glass-cloth MAT (Bt = 350 gr/m2), measurinq I = 14cm. b = 5,63cm, h = 0,68cm (h' = 0,568cm).
3.1.3. Marble specimen reinforced with resin glass-cloth STUOIA (Bε = 850 gr/m2), measuring I = 14cm. b = 5,63cm, h = 0,68cm (h' = 0,568cm).
3.1.4. Marble specimen reinforced with resin glass-cloth ROVING (Bε = 250 gr/m2), measuring I = 14cm. b = 5,63cm, h = 0,68cm (h' = 0,568cm).
3.2. Reinforced slabs of white Pentelic marble 0,76=0,82 cm thick
3.2.1. Marble specimen reinforced with fine-woven glass-cloth(Bε = 50 gr/m2),meaauring I = 14cm, b = 7cm, h = 0,7cm (h' = 0,718cm).
3.2.2 Marble specimenreinforced with resin glass cloth (Bε = 350 gr/m2), measuring = 14cm, b = 7cm. h = 0,8cm (h' = 0,73cm).
3.2.3. Marble specimen reinforced with resin glass-cloth STUOIA (Bε = 850 gr/m2),measuring I = 14cm, b = 7cm, h = 0,82cm (h' = 0,736cm).
3.2.4. Marble specimen reinforced with resin glass-cloth ROVING (Bt = 250 (gr/m2),measuring I = 14cm, b = 7cm, h = 0,8cm (h' = 0,73cm).
4. Calculation of the modulus of elasticity of the resin glass-cloth
4.1. Resin glass-cloth MAT 350
4.2. Resin glass-cloth STUOIA 850
4.3. Resin glass-cloth ROVING 250
5. Conclusions
CHAPTER THREE
REINFORCEMENT AND ELABORATION OF THE SLABS-PRODUCTS
1. Reinforcement and elaboration of the slabs
1.1. Elimination of dampness from the marble-slabs-granite slabs
1.2. Description of the reinforcement and eleboration of the slabs
2. Products
CHAPTER FOUR
ADVANTAGES OF THE NEW TECHNOLOGY PRODUCTS
INTRODUCTION
a) The relatively great specific weight, almost equal to that of a light metal as,for instance, aluminium.
b) The low modulus of rupture, having a negative influence on the slabs.
i) To the natural strains sustained by the decorative rocks during the blast of the stresses on the solid crust of the Earth.
ii) To the mechanical weak points having their origin to the use of explosive material (eg. dynamite).
iii) To the fact that the decorative rocks are not subject to the plastic deformation.
And it should be certainly noted that the decorative rocks are natural materials with a high enough modulus of elasticity (450.000-1.200.000 kg/em2).
CHAPTER ONE
CUTTING OF MARBLE BLOCKS-GRANIIE BLOCKS INTO THIN SLABS
1. Sawing with a frame machine
a) To the blades-bearer, diamond blades are placed, of a length greater than the normal one (5,00 m. instead of 4,20 m., which are the longest), bearing 55 instead of 42 diamond tiles (teeth), so that the great course of the blade-bearer might be fully evaluated
b) The base of the truck on which the marble blocks-granite blocks are loaded is not fixed, as usually, but it can be moved horizontally. These movements are contralled by a digital micrometer.
c) The downward speed (calata) may be controlled on the basis of the hardness of the decorative rock, so as to achieve a vertical saw and to obtain slabs of equal thickness. The descentional movement of the blade bearer is registered in a recording apparatus.
1.1. Description of the Sawing
1.2. Rendering of the method
2. Cutting by a block-tailor machine
a) To the disc-bearer twenty (20) vertical discs of 1600 mm in diameter and one horizontal disc of 450 mm in diameter are placed.
b) The dipping of the disc into the marble block-granite block is made progressively and cutting depth varies depending on the nature and the hardness of the decorative rock (4-5mm to the granites with low contents in quarz, 5-6 cm to the hard and 7-8 cm to the soft marbles for each full cycle of the discs-bearer.
c) The vertical movements of the discs-bearer and the cutting width of the linear tiles are controlled with digital micrometers.
2.1. Description of the cutting
2.2. Rendering of the method
CHAPTER TWO
REINFORCEMENT OF THE SLABS, THEORETICAL AND EXPERIMENTAL DATA
1.1. Slab measuring 1 = 320 cm, b = 155 cm, h = 0,5 cm.
1.2. Slab measuring 1 = 320 cm, b = 155 cm, h=0,7 cm.
2. Flexural strengths of the natural slabs
2.1. Specimen of cipollinic marble, measuring 1 = 14 cm, b - 5,63 cm, h - 0,52 cm.
2.2. Specimen of white Pentelic marble measuring 1- 14 cm, b 7 cm, h = 0,7 cm
3. Flexural strengths" of the reinforced slabs.
a) Polyester, epoxid, phenol resins and arco-xylane
b) Resin glass-clothes as :
- MAT (casually distributed fiber-glasses)
- STUOIA )crossed equally thick fiber-glasses)
- ROVING (longitudinal unequally thick fiber glasses)
a) Natural slab of cipollinic marble, 5 mm thick =Omax = 416,2 kg/cm3. Rf = 145 kg/cm2).
b)Natural slab of white Pentelic marble, 7 mm thick : O'max = 297,3 kg/cm3, Rf' = 190 kg/cm2).
3.1.4. Marble specimen reinforced with resin glass-cloth ROVING (Bε=250 gr/m2), measuring 1=11 cm, b-5,63 cm, h=0,68 cm (h'=0,568 cm).
Notes
a) In cases 3.1.3. and 3.1.4., the following fissures appear to the marble specimen with loads of 60,6 kg. corresponding to a moment of 0,297 kqm and to "flexural strengths" Rf6= 700,6 kg/cm2, that is an increase of the strength of the order of 383%.
b) In the cases 3.1.3. and 3.1.4. the ruptures of the reinforced marble specimen, with fragmentation of the broken zone, happens under the influence of about the same load (90,0 kg) corresponding to a moment of 0,445kgm. Consequently, the "flexural strength" of the reinforced marble specimen Rf7, to the limit of, rupture , reaches the 1050,9 kg/cm2, that is an increase of theorder of 625%.
3.2. Reinforced slabs of white Pentelic marble 0,76 ÷ 0,82 cm thick. 3.2.1. Marble specimen reinforced with fine woven resin glass cloth (BE=50 gr/m2) measuring 1=11 cm, b=7 cm, h=0,7cm(h'=0,718 cm).
3.2.3. Marble specimen reinforced with resin glass-cloth STUOIA (Bε= 850 gr/m2) measuring 1=14cm, b=7cm, h=0,82cm(h'=0,736cm).
3.2.4. Marble specimen reinforced with resin glass-cloth ROVING (Bε=250 gr/m2, measuring 1 = 14 cm, b = 7 cm, h = 0,8 cm (h' = 0,73 cm).
a) In the cases 3.2.3 and 3.2.4., the following fissures appear to the marble specimen with loads of 139,5 kg and 130,15 kg corresponding to moments of 0.684, kg and 0,638 kg and to "flexural strengths" Rf6 = 732,6 kg/cm2, xat Rf6 = 772,5 kg/cm2, i.e.inereases of strength of the order of 307% and 286%.
b) In cases 3.2.3. and 3.2.4., the ruptures of the reinforced marble specimen, with fragmentation of the broken zone, happens under the influence of about the same load that corresponds to a moment of 0,779 kgm and in "flexural strengths" Rf7 = 881,1 ke/cm2 and Rf7 = 895,6 kg/cm2, that is increases of the strengths of the order of 364% and 371%.
4. Calculation of the modulus of elasticity of the resin glass-clothes
4.1. Resin glass-cloth MAT 350
4.2. Resin glass-cloth STUOIA 850
4.3. Resin glass-cloth ROVING 250
5. Conclusions
Let it be a natural long-thin slab (εo=2710 kg/m ) of an 1 length, a b breadth and of an h thickness. Then, the weight per
current centimeter will be :
(1) becomes :
Examples :
Remark
REINFORCEMENT AND ELABORATION OF THE SLABS-PRODUCTS
1. Reinforcement and elaboration of the slabs
1.1. Elimination of dampness from the marble slabs-granite slabs.
In the bottom of a cast having the dimensions of the great slabs (3,30xl,60 m or 3,30 x 0,63 m( and a depth of 3÷5 cm, the formica is placed. On the cover of the cast the marble slab is placed, with the residn glass cloth facing the interior of the cast. The empty space between the slab and the formica is filled with polyurethane which is enlaged and solidified within a very short period of time (eg. 20 esec.).
From the above great slabs of the two first classes of products, the following standard products can be issued
a)Tiles measuring 30x60 cm, 40x80 cm and 50x50 cm.
b)Modulmarmo and Modulgranite measuring 25x50 cm and 30x30 cm.
c)Small tiles measuring 15x30 cm and 15x15 cm.
ADVANTAGES OF THE NEW TECHNOLOGY PRODUCTS
a) Their weight is the half (see fig. 14) and consequently their transport cost is considerably decreased.
b) Their rendering is more than the double in square meters, per cubic meter of marble block-granite block (see Fig. 15) and thus there is a considerable decrease of the cost of the reinforced slab deriving from the raw material, while in parallel they greatly contribut to the economization of non renewable mineral resources as the marbles and the granite.
c) The allow a very great increase of the max length of the natural slabs, while at the same time, they offre a great impact resistance, so that the risk of their rupture during transport and posing is decreased to the minimum.
d) They present a minimum water absorption and excellent thermal isolation properties (mainly the RDR panelling products).
e) They attribut to the decorative rocks, the optimal possible adhesion to the building elements, so that they can be characterized as self anchored elements.
f) They contribute to the exploitation of valuable marbles mechanically deformed by natural and technical reasons.
g) They cost cheaper, as the charging of the costing prices from the reinforcement materials is covered by the over that the double rendering.
h) They offer greater profits, as they are sold at higher prices and they cost cheaper.
For the application of the new sawing method, the marble blocks-granite blocks should be orthogonal and they should be of dimensions fully evaluating the productive possibility of the frame machine.
The dimensions of the block sawed were 3,30 x 1,85 x 1,65 =10 m3, its weight was 27,10 tons and its type was that of the green cipollinic marble of Eubea isl. (Fig. 1).
The frame machine used for the experiments was a modern frame machine with a great linear velocity (= 2,5 m/min(, but with the following construction differentiations-modifications :
a) To the blades-bearer, diamond blades are placed, of a length greater than the normal one (5,00 m. instead of 4,20 m., which are the longest), bearing 55 instead of 42 diamond tiles (teeth), so that the great course of the blade-bearer might be fully evaluated
b) The base of the truck on which the marble blocks-granite blocks are loaded is not fixed, as usually, but it can be moved horizontally. These movements are controlled by a digital micrometer.
c) The downward speed (calata) may be controlled on the basis of the hardness of the decorative rock, so as to achieve a vertical saw and to obtain slabs of equal thickness. The descentional movement of the blade bearer is registered in a recording apparatus.
The length of the blade and the number of the teeth may vary and this docs not mean a change to the principle of operation.
For this new cutting method, the marble blocks-granite blocks should be orthogonal and they should be of dimensions fully evaluating the productive possibility of the block- tailor machine.
3 The dimensions of the block cut were 3,30 x 1,20 x 1,35 5,35 m , its weight was 14,10 tons and its type that of the green cipollinic marble of Eubea island (Fig. 2).
The block tailor machine used for the experiments was one of a great linear velocity (1,20 m/min on going and 5 m/min on return), but with the following construction differen- ciations-modifications :
a) To the disc-bearer twenty (20) vertical discs of 1600 mm in diameter and one horizontal disc of 450 mm in diameter are placed.
b) The dipping of the disc into the marble block-granite block is made progressively and cutting depth varies depending on the nature and the hardness of the decorative rock (4-5mm to the granites with low contents in quarz, 5-6 cm to the hard and 7-8 cm to the soft marbles for each full cycle of the discs-bearer.
c) The vertical movements of the discs-bearer and the cutting width of the linear tiles are controlled with digital micrometers.
It is clear that, the heating of the surfaces alone by electrical resistances or any other way(eg. ultrared rays) does not solve the problem. Because in these cases the elimination of the dampness takes place only superficially.
This serious impediment was gone pas in this invention, by the application of the known physical law according to which, the water evaporation (dampness) is correlated (increases) with the increase of temperature and the decrease of the atmospheric pressure.
Evaluating this second parameter, the elimination of humidity is effected in two phases. During the first phase, a group of slabs is placed into a concrete pool measuring 3,50m·1,80m· 1,80m = 11,5 m3, which is under the ground and is vaccuum closed by a specific resistant cover. By a vaccuum pump, the pressure is decreased in the pool from 760 to about 70 Torr.
After one hour, the dampness, under the form of capillary water, has been eliminated.
For the reinforcement of the natural slabs we used two groups of materials :
a) Polyester, epoxid, phenol resins and arco-xylane
b) Resin glass-clothes as :
- MAT (casually distributed fiber-glasses)
- STUOIA )crossed equally thick fiber-glasses)
- ROVING (longitudinal unequally thick fiber glasses)
The volumetric weight εo and the modulus of elasticity E' of the reinforcement materials is 1450 kg/m3 and 220.000 kq/cm2 respectively.
After the elimination of the dampness in the vacuum pool, the double slabs, with polyurethane among them are driven to first table ball and thence, by a roller conveyor to the heating apparatus of the upper surface of the slab with electric resistances. Immediately afterwards, the slabs are advanced to the resin plant. Then, a resin glassdothis attached to the slabs and finally, if desirable, gravel of about three ml. is thrown to the still damp surface, by a special apparatus.
The double slab with the resin glass-cloth and the gravel, to the upper surface thereof, is driven via the second table ball to the continuous belt and thence to the first table ball.
This course of more than twenty meters is enough for the heardening of the resin. By the use of the calibration machine, a total thickness of resin glass cloth and gravel of 3,5 mm is achieved.
To this point, the double slab is reversed and the previous procedure is followed, so that the other surface too be covered with resin glass-cloth and gravel.
The double slab covered in both surface with resin glass-cloth (Fig. 9) goes through a special saw belt, the polyurethane is cut and so it is separated into two slabs.
These slabs can be standardized by the cross-cut saws and then, having been elaborated in the grinding and polishing machine from the surface which is covered with polyurethane, they are driven to the second table-ball and then packed.
The necessary equipement and the flow of the elaboration procedure for the reinforcement of the natural slabs, is given in Fig. 10.
The products issued by the above elaboration may be characterized by the general term of Reinforced Decorative Rocks (RDR) (Fig. 11). If gravel is attached to the reinforced decorative rocks, new products called Autoanchored RDR are issued(Fig. 12)
To the surface of the decorative rock reinforced with resin glass-cloth, polyurethane, 3T5 cm thick can be attached, acting on one had as an isolating material and on the other hand multiplying, by the formica sheet, the inflexibility of the decorative rock (Fig. 13).
These composite products will be sold under the name of RDR Panelling and will be produced as follows :
It is specified that the breadth and the order of position of the machines, as well as the number of the sprayers of resin and the abrasion-polishing heads described to the above figure may vary.
In the bottom of a cast having the dimensions of the great slabs (3,30x1,60 m or . 3,30 x 0,63 m( and a depth of 3?5 cm, the formica is placed. On the cover of the cast the marble slab is placed, with the residn glass cloth facing the interior of the cast. The empty space between the slab and the formica is filled with polyurethane which is enlaged and solidified within a very short period of time (eg. 20 esec.).