WO2006068528A2

WO2006068528A2 - Process and installation for obtaining cellular concrete and cellular concrete obtained thereby

Info

Publication number: WO2006068528A2
Application number: PCT/RO2004/000019
Authority: WO
Inventors: Constantin Profir
Original assignee: Constantin Profir
Priority date: 2004-12-21
Filing date: 2004-12-21
Publication date: 2006-06-29
Also published as: WO2006068528A3

Abstract

The invention relates to a process and an installation for obtaining cellular concrete and cellular concrete thus obtained that may be used in masonry and thermal and sound insulation works, that may be placed directly or cast into moulds. According to the invention, the process is characterized in that, in the mixing chamber there takes place the introducing of the dry solid components of the mixture, while rotating in the mixing chamber there is introduced air, followed by introducing a mixture of water and additives comprising the gas entrainer and the organic binders, and continuing the rotation then in a discharge chamber there taking place the introducing of the air, equal as a value with the pressure in the mixing chamber, then putting the mixing chamber in communication with the discharging chamber, finally there taking place the gravitational discharging into the mould and equalizing the pressure in the discharge chamber and the pressure in the mixing chamber with the atmospheric pressure, and after the expansion, the mixture mass is discharged from the discharging chamber wherein the expansion took place, and it is let to rest for 5 - 10 hours at the atmospheric pressure followed by the said cutting and palletizing operations.

Description

PROCESS AND INSTALLATION FOR OBTAINING CELLULAR CONCRETE AND CELLULAR CONCRETE OBTAINED THEREBY

The invention relates to a process and an installation for obtaining cellular concrete and to cellular concrete obtained thereby, which can be used in masonry and thermal and acoustical insulation works, and that can be placed directly or cast into moulds.

There are known processes for obtaining the cellular concrete, which consist in forming, within a mixing chamber of a vessel, a mixture which comprises in a cubic meter of cellular concrete 62% of 0 - 3 mm grain size sand, 24% cement, 12% water, 1.2% air entrainers, followed by tightly closing the mixing chamber and creating therein a pressure that is higher than the atmospheric pressure by one bar at the most, by introducing the pressurized air, then subjecting the mixture to a rotary motion by rotating the vessel for 10 minutes at a rotary speed of 40 rpm, then lowering the pressure in the mixing chamber to the value of the atmospheric pressure which causes the air bubbles to expand within the mixture mass, and after 3 - 5 minutes the mixture is discharged into moulds or placed due to the hydrostatic pressure of the mixture in the mixing chamber.

The disadvantages of these processes consist in that the expansion takes place in the mixing chamber so that during the handling of the mixture up to the moulds or placement, because of the internal friction occurred during the flow, a part of the air bubbles are outlet from the mixture leading to the increase of the final density and to an increased thermal conductivity, and when placing the mixture into moulds or during its placement, there takes place a segregation of the 2- 3 mm diameter grains, that does not confer homogeneity on the cellular concrete mass and does not allow to obtain relatively small blocks for masonry.

There are known installations for obtaining the cellular concrete, which comprise a cylindrically shaped vessel having the longitudinal axis contained in a horizontal plane, rotatably sustained by means of some short shafts and by some bearings to some supports, having a charging and discharging hole that can be closed tightly by means of a flap driven from the outside, the rotary motion being transmitted from a motor by means of a speed reducer, to a crown gear fastened to the external side of the vessel, a mixing chamber of the vessel being connectable with the environment through a cock allowing the pressurized air to be introduced into or discharged from the chamber, and finally the mixture wherein the expansion took place is decanted, through a flexible pipe, into a mould or placed at the atmospheric pressure.

The disadvantages of these installations consist in that they do not allow to handle the mixture from the mixing chamber into the mould while maintaining the pressure of the gases in the mixture pores at the value extant in the mixing chamber, carrying out the pore filling only with air that has a low thermal conductivity and carrying out the mixture expansion only inside the mixing chamber.

There are known cellular concretes comprising 62% of 0 - 3 mm grain size sand, 24% Portland cement, 12% water, 1.2% air entrainers, which after mixing and expansion form a mixture that is cast into moulds or placed under a pressure equal to the atmospheric pressure, the casting being carried out under the hydrostatic pressure created by the mixture height inside the mixing chamber, the pores in the mixture being full of air.

For a cellular concrete having a density of 500 kg/m³ there is obtained a compression strength of 2.8 N/mm², water absorption of 28%, thermal conductivity of 0.09 VWm⁰K, and for the assortment of concrete of 700 kg/m^3> the estimated values are the compression strength of 5.4 N/mm², 24 - 26% water absorption and 0.14 VWm⁰ K thermal conductivity.

The disadvantages of these types of cellular concrete consist in that they have the pores filled with air, achieving only a relatively high thermal conductivity, the concrete properties such as the density, compression strength, water absorption and thermal conductivity have modest values though they are superior to the gas-formed concretes.

The technical problem solved by the inventions in the group of inventions consists in creating, within the mixture mass, some pores filled with gas, having a reduced thermal conductivity at a pressure higher than the atmospheric pressure allowing to obtain a cellular concrete whose density may be varied within relatively wide limits, having a relatively reduced value of the thermal conductivity in the conditions in which the volume of pores should be maintained while transferring the mixture from the mixing chamber and there should not take place the segregation of the components.

It has been ascertained after performing more simulations and experiments that by increasing the pressure in the mixing chamber to values higher than one bar, it is possible to obtain, at values of the desired densities that are different from one batch to the other, surprising positive values for the compression strength, water absorption and thermal conductivity of the cellular concrete.

In this context, it is of major importance to maintain the same density of the mixture from the mixing chamber to the mould, after the mixture transfer, situation that is possible only in the conditions of maintaining the same pressure along the whole mixture discharging path.

It has also been ascertained that for ensuring a good homogeneity of the pore structure the mixture shall not contain grains of more than 2 mm diameter, which can lead to the segregation within the mould to a non-uniform structure of the cellular concrete mass.

By introducing a value of the homogenizing pressure of - 0.5 ... - 0.2 bar in the process claimed by the invention, the pores are filled with gas, such as a mixture of air and argon or argon, that have small thermal conductivity.

By varying the mixing chamber pressure, different pore structures and consequently different densities may be obtained for the same cellular concrete composition.

The process claimed by the invention eliminates the disadvantages shown before by that, the solid and dry components of the mixture are introduced into a mixing chamber, then the communication thereof with the environment is stopped and a pressure having a value of

- 0.5... - 0.2 bar is created within the chamber, the vessel being rotated with a rotary speed of 15 ... 48 rpm for 2 ... 6 minutes, followed by introducing into the chamber, while continuing to rotate the vessel, air or preferably a mixture containing 1 to 99% air and 99 ... 1 % argon, respectively, or only argon, at a pressure ranging from 1 to 8 bar, followed by introducing, with a pressure of 1 ... 8 bar, a mixture of water and additives comprising the gas entrainer to which organic binders may be added, the gas introducing pressure and mixture pressure being of 1 ... 8 bar, the rotation continuing with the same rotary speed of 15 ... 48 rpm for 5 ... 15 minutes, then in a discharging chamber there takes place the introducong of air at a pressure of 1 ... 8 bar, equal to that in the mixing chamber, then putting the mixing chamber in communication with the mixture discharging chamber, along a path, at a pressure equal to the pressure in the mixing chamber and discharging chamber, finally there taking place the equalizing of the pressure in the discharging chamber with the atmospheric pressure with a view to obtaining the expansion of the gas bubbles attached in the mixture mass, and after the expansion, the mixture mass discharged from the discharging chamber wherein the expansion took place is let to rest for 5 - 10 hours at the atmospheric pressure.

According to the invention, in another embodiment, the process eliminates the disadvantages shown before by that from the mixing chamber there is introduced pressurized air at a pressure value preferably of 5 ... 8 bar, continuing the rotation of the vessel with the same rotary speed for 5 ... 15 minutes, then introducing with the same pressure, into the mixing chamber, water and additives and organic binders, if appropriate, while continuing the rotation with the same mentioned rotary speed, then providing in the discharging chamber and along the said discharging path a pressure whose value is equal to the pressure in the mixing chambre, namely of 5 ... 8 bar, then the movement of the vessel is stopped and there takes place the discharging of the mixture into the discharging chamber in the mould, and then here takes place the equalizing of the pressure in the discharging chamber with the atmospheric pressure.

In another embodiment, the process claimed by the invention eliminates the disadvantages shown before by that the pressure of 1 .. 8 bar in the mixing chamber is slowly lowered with or without interruption for maximum 1 minute at each one-bar step until de pressure reaches the value of the atmospheric pressure, when the expansion of the gas bubbles in the mixture mass is completed and the mixture is discharged at the atmospheric pressure.

According to the invention, the installation eliminates the disadvantages shown before by that, lengthwise of the generatrix of the cylindrically shaped vessel there being mounted some baffle plates, having a preferably semicircular-shaped cavity placed in the rotation direction of the vessel in communication with a pipe connection secured to the vessel, in front of the hole thereof there being secured a nipple of a connecting subassembly in relation therewith there being mounted a communication valve, downstream the nipple there being mounted an elbow which has a lower portion which partially penetrates into a discharging chamber confined by another lower vessel of a discharging subassembly, the elbow having a hole that is closed by an articulated flap, to the lower portion in the discharging chamber there being placed a mould on some rollers, said mould being introduced or withdrawn form the discharging chamber through a hole that may be closed by a cover operated by a hydraulic cylinder, the vessel of a subassembly of the mixing chamber being sustained on one of the said supports, by a tubular shaft of a subassembly for changing the pressure and for feeding water with a content of solids and additive and organic binders, if appropriate.

The disadvantages of the known technical solutions are also eliminated by the novelty of the elements constituting the installation claimed by the invention, as they are contained in the dependent claims 5 .... 7, as it results from the aspects that will be presented hereinafter.

According to the invention, the installation comprises the subassembly for modifying the pressure and for feeding water and additives, and organic binders, if the case may be, said subassembly being provided with the short tubular shaft axially penetrated by a pipe that also passes through a sealing box, on the pipe there being secured a "T'-shaped connection having mounted one of some cocks on each of the three arms, said cocks being handled to create, in the mixing chamber, a negative pressure, an overpressure or for introducing water, additives and organic binders.

According to the invention, the installation has the connecting assembly provided with some gaskets preferably having the "O" shape in the cross section, the subassembly having a nipple in whose middle region there are secured two diametrically opposing pins to which there being articulated a fork-shaped body of a control part whose handle is articulated to a short vertical support.

According to the invention, the installation comprises the upper vessel of the mixing chamber subassembly that has two 5 ... 10 degrees inclination troughs in front of the discharging hole in order to direct the mixture with a view to being discharged from the mixing chamber through the open hole.

The cellular concrete claimed by the invention eliminates the disadvantages shown before by that it is constituted by a mixture consisting of 48 ... 62% of 0 - 1 mm grain size sand, 48 ... 30% Portland cement with or free of additions consisting of ash and slag, 27 ... 18% water, 0.3 ... 0.08% AAS (surface active agent), 1 ... 0.6% addition consisting of clay, these values being related to a cubic meter, this cellular concrete having a water absorption of 18 ... 10%, a thermal conductivity of 0.06 ... 0.12% VWm⁰K and a compression strength of 2.4 ... 8.2 N/mm², these values being obtained in the conditions in which the homogenizing pressure is of - 0.5 .... - 0.2 bar, the homogenizing time of 4... 3 minutes, there being employed a mixture consisting of argon and air in a 3 ... 1 or 1/1 ratio, a mixing pressure of 5 ... 2.5 bar and a mixing time of 5 ... 15 minutes, there being obtained concretes with the volume weight ranging from 400 to 900 kg/m³.

The cellular concrete claimed by the invention, in another embodiment, eliminates the disadvantages shown before by that it is constituted from a mixture consisting of 48 ... 64% of 0 - 1 mm grain size sand, 44 ... 31% Portland cement with or free of additions consisting of ash and slag, 5...0.14% organic binders such as PAV (vinyl polyacetate), CV (vinyl chloride) or BNS (butadiene acrylonitrile rubber), preferably BNS, 18 ... 12% water, 0.2 ... 0.1% AAS, 1 ... 0.6% addition consisting of clay, these values being related to a cubic meter, this cellular concrete having a water absorption of 18 ... 10%, a thermal conductivity of 0.06 ... 0.12 WVm⁰K and a compression strength of 2.4 ... 8.2 N/mm², these values being obtained in the conditions in which the homogenizing pressure is of - 0.5 ... - 0.2 bar, homogenizing time of 4 ... 3 minutes, there being employed a mixture consisting of argon and air in a 3 ... 1 or 1 ... 1 ratios, a mixing pressure of 5 ... 2.5 bar for 5 ... 15 minutes, there being obtained concrete with the volume weight ranging from 400 to 700 kg/m³.

The process, installation and the cellular concrete according to the inventions from the group of inventions present the following advantages:

- between the amount of gas in the mixture mass after formation and the one in the cellular concrete wherein the gas bubbles expansion took place there exist relatively small differences of 3 ... 5%;

- there may be obtained cellular concrete with controlled and varied densities from one batch to the other for the same composition;

- the cellular concrete has a fine homogenous structure without the participation of some particles of more than 2 mm diameter;

- allow the use of some gases or of a mixture of gases leading to obtaining a cellular concrete with a relatively reduced thermal conductivity;

- the construction of the installation as well as the application of the process are relatively simple in the conditions existing on the site;

- the installation maintenance is easy;

- the electric energy consumption is relatively reduced, by the elimination, for example, of the stages and subassembly of the installation for grinding the solid components and for autoclaving.

There are given hereinafter 7 examples for carrying out the cellular concrete claimed by the inventions from the group of inventions, in relation with the figures 1 ... 8 which represent:

- Figure 1 - longitudinal section through an upper vessel of a mixing subassembly;

- Figure 2 - transverse section about the plane A -A given in Figure 1 ;

- Figure 3 - longitudinal section through a lower vessel of a discharging subassembly;

- Figure 4 - side view of a connecting piece of a connecting subassembly;

- Figure 5 - top view of the connecting piece;

- Figure 6 - partial longitudinal section through the upper and lower vessel;

- Figure 7 - side view of the vessels and a fracture view in the lower vessel;

- Figure 8 - partial longitudinal section through the upper vessel.

The installation claimed by the invention consists of a mixing subassembly A provided with a pipe connection 1 which by means of a connecting subassembly B ensures the communication with a discharging chamber a confined within a discharging subassembly C.

An upper vessel 2 of the subassembly A is entrained in rotary motion by a driving subassembly D.

To the front side, in connection with the subassembly A there is mounted a subassembly E for modifying the pressure and for feeding water and additives as well as organic binders, if appropriate.

The subassembly A consists of the vessel 2 whose walls are made of materials resisting to a pressure of 20 ... 30 bar, preferably having a cylindrical shape, with the longitudinal axis generally positioned in a horizontal plane, which confines a mixing chamber b. The vessel 2 is mounted by means of some bearings 3 on some supports 4. The diameter of the vessel 2 may preferably be of 1200 ... 2400 mm.

In the vessel 2 there is provided a hole c for admission to the chamber b confined by a circular collar d to which there is secured the pipe connection 1. The hole c may by tightly closed by operating a lever 5 to whose end placed in the chamber b, there is secured a flap in relation to which there being mounted a resilient annular gasket 7. In one of the bearings 3 there is mounted a short shaft 8 integral within the chamber b with a diaphragm 9.

The driving subassembly D comprises a motor 10 provided with a speed changer wherefrom the motion is transmitted by means of a reducer 11 to a pinion 12 engaged with a toothed wheel 13 mounted outside the vessel 2.

In front of the hole c there are provided two troughs e each having a slope with a value, from the upstream to the downstream, of 5 - 10 degrees so as to ensure the mixture flow control from the chamber b towards the hole c when this is positioned at the lower side of the vessel 2.

On one side of the collar d, along one of the troughs e, in the vessel 2 there are mounted a pressure gauge 14 and a safety valve 15.

Lengthwise of the generatrix of the cylinder that constitutes the shape of vessel 2 there are mounted some baffle plates 16 having a semispherical cavity f positioned to the direction of rotation of the vessel 2, these baffle plates 16 allowing to be staggered by angles of values ranging from 10 - 60 degrees.

These baffle plates 16 may be placed along the whole length of the generatrix or along a length smaller than that, but different from one baffle plate 16 to the baffle plates 16 adjacent thereto, starting from one end or the other of the generatrix.

The connecting subassembly B consists of a nipple 17 provided to the upper side with a flared portion g, which to the inner top side supports an annular gasket 18 having a "O"-shape in the cross-section. To the middle region of nipple 17 there are secured two diametrically opposing pins 19 to which there is articulated a fork-shaped head h of a manoeuvring piece 20 provided with a handle i to this end.

The handle i is articulated by means of a bolt 21 to a short vertical support 22 integral with a lower vessel 23 of the discharging subassembly C which confines the discharging chamber. In connection with the nipple 17 there is mounted a straightway cock 24 to which there may be connected a pressurized air source, not represented in the figures, or that can be put in communication with the environment.

The connecting subassembly B further comprises an elbow 25 provided with an upper portion j wherein there is mounted a gasket 26 preferably having an "O" shape in the cross section. This gasket 26 is in contact with the nipple 17. An inner portion k of the elbow 25 partially penetrates in the discharging chamber, communicating therewith through a discharging hole I and being closed by a flap 27 articulated to the portion k.

The vessel 23. has a cylindrical shape and preferably has the longitudinal axis located horizontally, and generally has a diameter of 1200-2400 mm and in a lower portion m in the chamber a there are secured some supports 28 which sustain some rollers 29 which can contact a lower wall n of a mould 30.

A front portion of the mould 30 is positioned near the flap 27, to the upper side of the vessel 23 there are secured an access cock 31 and a pressure gauge 32. To the lower portion m of the vessel 23, near a rear hole p of the vessel 23 there is mounted a hydraulic cylinder 33 whose rod 34 is articulated to a cover 35 wherein there is mounted an annular gasket 36, which upon closing the hole p, comes into contact with an inner seat q located around said hole.

The subassembly E consists of a short tubular shaft 37 stiffened to one of the membranes 9, mounted in one of the bearings 3, axially penetrated by a pipe 38 which also penetrates a sealing box 39 provided with means for taking over the wear of a gasket, having a construction known per se, not represented in the figures.

A "T"-shaped pipe connection 40 is secured to the pipe 38, on each of the three arms r, s, and t of the pipe connection there is mounted one of some cocks 41 , 42 and 43, by whose manoeuvring a negative pressure or an overpressure may be created in the mixing chamber b, or there may be introduced water with additives or organic binders, if appropriate.

For obtaining a batch of cellular concrete mixture, the vessel 2 is positioned with the hole c oriented upwards so as to allow the desired quantities of sand and cement to be introduced into the chamber b, then the flap 6 is operated by means of the lever 5 for closing the hole c. The cock 41 is operated so as to create a negative pressure with a value ranging from - 0.5 ... - 0.2 bar in the chamber b through the arm r, then the cock 41 is closed, the motor 10 is started and the vessel 2 is rotated with a rotary speed of 28 rpm for 3 minutes.

Then by opening the cock 42, argon or a mixture of argon and air at a pressure of 1 ... 5 bar is introduced into the chamber b through the pipe 38, then, by maintaining the same rotary speed of the vessel 2, through the arm t with the cock 43 open, in the conditions in which the cock 42 is closed, a mixture of water, AAS, clay is introduced into the chamber b and the rotation of vessel 2 is continued for further 5 - 10 minutes, preferably with the same rotary speed.

During this time, the mould 30 is introduced into the discharging chamber a and then the hydraulic cylinder 33 is operated for closing the hole p, wherethrough the mould 30 was manoeuvred by the cover 35. By opening the cock 31 air is introduced into the chamber a at a pressure equal to the pressure within the vessel 2.

The air pressure within the chamber a leads to closing the hole 1 by the flap 27.

After ending the mixing cycle, the motor 10 is stopped so that the hole c should be positioned downwards to allow the nipple 17 to be connected with the pipe connection 1 of the connecting subassembly B.

By opening the cock 24, the inner side of the connecting subassembly B is put in communication with the pressurized air source that supplies air at a pressure equal to the air pressure within the chambers a and b, thereafter the cock 24 is closed. From this moment the flap 6 may be moved so as to release the hole c and the mixture from chamber b is decanted by gravity through the subassembly B and by opening the flap 27 into the mould 30.

Then the cock 31 is opened until the pressure in the chamber a is slowly equalized with the atmospheric pressure. The subassembly B is disconnected by operating the part 20, so that a new mixture batch may be prepared within the vessel 2, and the mould 30 wherein the mixture expansion took place, because of the decrease of pressure in chamber a, is evacuated therefrom through the hole p as a consequence of acting upon the cover 35 that opens it.

The mould 30 is let in a place safe from bad weather for 5 - 10 hours for achieving a minimum strength of the mixture, then the concrete is subjected to the cutting and palletizing steps that are known per se.

Example 1 :

In a stationary vessel 2 whose mixing chamber b has a capacity of 4 cubic meters, having the charging hole positioned to the upper side, there are introduced the components of the mixture for preparing the cellular concrete with an apparent density of 400 kg/m³, said components consisting of 180 ... 200 kg of 0 - 1 mm grain size sand, 180 ... 200 kg Portland cement with or free of additions consisting of ash and slag, the mixing chamber b is tightly closed in relation to the environment, and by opening the cock 41 , through the arm r there is created a pressure of - 0.5 bar therein. The cock 41 is turned off and then the mixture is subjected to a rotary motion due to the rotation of the vessel 2 with a rotary speed of 28 rpm for 4 minutes, thereby homogenizing the mixture, then through the arm s and by turning on the cock 42 a mixture of gases comprising argon and air in a 3 ... 1 ratio is introduced at a pressure of 5 bar. The cock 42 is turned off and through the arm t, by turning on the cock 43, a mixture consisting of 108 liters of water, 1.5 liters of AAS (surface- active agent comprising calcium and ammonium lignosulphate , sodium alkylarylsulphonate), 4 kg of clay is introduced into the mixing chamber b while the vessel 2 is in a rotary motion. The mixing is continued for 7 minutes then the mixture is decanted through the connecting subassembly B into the mould 30 extant in the discharging chamber a, wherein there is a pressure of 5 bar, then, by turning on the cock 31, the pressure value within the discharging chamber a is equalized with the atmospheric pressure value and there takes place the mixture expansion by increasing the volume of the gas bubbles attached to the mixture by the AAS. The mould 30 with the expanded mixture is taken out of the chamber a and it is conveyed to a place safe from bad weather, where, after 5 - 10 hours the cellular concrete is taken over and cut and palletized in a manner known per se in respect of the process steps.

The concrete obtained thereby has an apparent density of 400 kg/m³, 12% water absorption, a thermal conductivity of 0.06 VWm⁰K , a compression strength of 2.4 N/mm² and it is employed for carrying out the masonry and insulation works.

Example 2:

In a stationary vessel 2 whose mixing chamber b has a capacity of 4 cubic meters, having the charging hole located to the upper side, there are introduced the components of the mixture for preparing the cellular concrete with the apparent density of 500 kg/m³, these components consisting of 200 ... 250 kg of 0 -1 mm grain size sand, 200 ... 250 kg Portland cement with or free of additions consisting of ash and slag, the mixing chamber b is closed tightly relative to the environment, and by manoeuvring the cock 41 , through the arm r there is created a pressure of - 0. 4 bars within the chamber b. The cock 41 is turned off and the mixture is subjected to a rotary motion due to rotating the vessel 2 with a rotary speed of 28 rpm for4 minutes, thereby the mixture being homogenized, thereafter, through the arm s as a result of turning on the cock 42, a mixture of gases consisting of argon and air in a 3 ... 1 ratio is introduced into the chamber b at a pressure of 4.5 bar. The cock 42 is turned off and through the arm t, as a result of turning on the cock 43 there is introduced a mixture consisting of 135 liters of water, 1.3 liters of AAS, 5 kg of clay , in the conditions in which the vessel 2 is in a rotary motion. The mixing is continued for 7 minutes then the mixture is decanted through the connecting subassembly B into the mould 30 extant in the discharging chamber a having a pressure of 4.5 bar, then, by turning on the cock 31, the pressure within the discharging chamber a is slowly equalized with the atmospheric pressure and there takes place the expansion within the mixture mass by increasing the volume of the gas bubbles attached by AAS in the mixture. The mould 30 comprising the expanded mixture is taken out of the chamber a and it is conveyed to a place safe from bad weather where, after a period of 5 - 10 hours the cellular concrete is subjected to the known cutting and palletizing operations.

The concrete obtained this way has an apparent density of 500 kg/m³, a water absorption of 16%, a thermal conductivity of 0.08 VWm⁰K, a compression strength of 3.0 N/mm² and it is used for carrying out the masonry and thermal and sound insulation works.

Example 3:

In a stationary vessel 2 whose mixing chamber b has a capacity of 4 cubic meters, having the charging hole positioned to the upper side, there are introduced the components of the mixture for preparing the cellular concrete having the apparent density of 700 kg/m³, said components consisting of 420 ... 450 kg of 0 -1 mm grain size sand, 220 ... 250 kg of Portland cement with orfree of additions consisting of ash and slag, the mixing chamber b is tightly closed relative to the environment, and by manoeuvring the cock 41 , through the arm r, a pressure of -.0.3 bar is created inside the chamber b. The cock 41 is turned off and the mixture is subjected to a rotary motion by rotating the vessel 2 with a rotary speed of 28 rpm for 3 minutes, thereby homogenizing the mixture, thereafter, through the arm s, as a consequence of turning on the cock 42, a mixture of gases consisting of argon and air in a 1 ... 1 ratio is introduced into the chamber b at a pressure of 3.5 bar. The cock 42 is turned off and through the arm t, as a consequence of turning on the cock 43, a mixture consisting of 135 I of water, 1.0 I of AAS, 5 kg of clay is introduced, in the conditions in which the vessel 2 is in a rotary motion. The mixing is continued for 7 minutes, then the mixture is decanted through the connecting subassembly B into the mould 30 extant in the discharging chamber a having a pressure of 3.5 bar, thereafter, by turning on the cock 31 , the pressure within the discharging chamber a is slowly equalized with the atmospheric pressure and there takes place the expansion in the mixture mass by increasing the volume of gas bubbles attached in the mixture by the AAS. The mould 30 with the expanded mixture is taken out of the chamber a and conveyed to a place safe from bad weather, where after 5 -10 hours the cellular concrete is subjected to the known cutting and palletizing operations.

The. concrete obtained this way has an apparent density of 700 kg/m³, a water absorption of 14%, a thermal conductivity of 0.09 VWm⁰K, a compression strength of 5.8 N/mm² and it is employed for carrying out the strength masonry works and insulation works.

Example 4:

In a stationary vessel 2 whose mixing chamber has a capacity of 4 m³ , having the charging hole c positioned to the upper side, there are introduced the components of the mixture for obtaining the cellular concrete with the apparent density of 900 kg/m³, said components consisting of 550 ... 600 kg of 0 - 1 mm grain size sand, 250 ... 300 kg of Portland cement with or free of additions consisting of ash and slag, the mixing chamber b is tightly closed relative to the environment, and by manoeuvring the cock 41 , a pressure of - 0.2 bar is created through the arm r inside the chamber b. The cock 41 is turned off and the mixture is subjected to a rotary motion by the rotation of the vessel 2 with a rotary speed of 28 rpm for 3 minutes, thereby homogenizing the mixture, then through the arm s as a result of turning on the cock 42, a mixture of gases consisting of argon and air in a 1 ... 1 ratio is introduced into the chamber b, at a pressure of 2.5 bar. The cock 42 is turned off and through the arm t, as a result of turning on the cock 43, a mixture consisting of 162 I of water, 0.8 I of AAS, 6 kg of clay is introduced, in the conditions in which the vessel 2 is in a rotary motion. The mixing is continued for 7 minutes then the mixture is decanted through the connecting subassembly B into the mould 30 extant in the discharging chamber having a pressure of 2.5 bar, then by turning on the cock 31 , the pressure inside the discharging chamber a is slowly equalized with the atmospheric pressure and there takes place the expansion within the mixture mass by increasing the volume of the gas bubbles attached in the mixture by the AAS. The mould 30 with the expanded mixture is taken out of the chamber a and conveyed to a place safe from bad weather, where after a period of 5 -10 hours the cellular concrete may be subjected to the known cutting and palletizing operations.

The concrete obtained this way has an apparent density of 900 kg/m³, a water absorption of 10%, a thermal conductivity of 0.12 VWm⁰K, a compression strength of 8.2 N/mm² and it is used for carrying out the strength masonry works and insulation works.

Example 5:

In a stationary vessel 2 whose mixing chamber b has a capacity of 4 m³ having the charging hole c positioned to the upper side, there are introduced the components of the mixture for p\obtaining the cellular concrete having the apparent density of 400 kg/m³, said components consisting of 180 ... 200 kg of 0 - 1 mm grain size sand, 160 ... 180 kg of Portland cement with or free of additions consisting of ash and slag, the mixing chamber b is tightly closed relative to the environment, and by operating the cock 41 , a pressure of 5.0 bar is created within the chamber b through the arm r. The cock 41 is turned off and the mixture is subjected to a rotary motion by rotating the vessel 2 with a rotary speed of 28 rpm for 4 minutes, thereby homogenizing the mixture, thereafter through the arm s as a result of turning on the cock 42, a mixture of gases consisting of argon and air in a 3 ... 1 ratio is introduced into the chamber b at a pressure of 5.0 bar. The cock 42 is turned off and through the arm t, as a result of turning on the cock 43, there is introduced a mixture consisting of 721 of water, 1.01 AAS, 3.6 kg of clay, 20 kg of organic binders selected from PAV, CV and BAN, in the conditions in which the vessel 2 is in a rotary motion. The mixing is continued for 10 minutes, then the mixture is decanted through the connecting subassembly B into the mould 30 extant in the discharging chamber a, having a pressure of 5.0 bar therein, thereafter by turning on the cock 31 , the pressure within the discharging chamber a is slowly equalized with the atmospheric pressure and there takes place the expansion in the mixture mass by increasing the volume of the gas bubbles attached in the mixture by the AAS. The mould 30 with the expanded mixture is taken out of the chamber a and conveyed to a place safe from bad weather, where after 5 - 10 hours the cellular concrete may be subjected to the known cutting and palletizing operations.

The concrete obtained this way has an apparent density of 400 kg/m³, a water absorption of 12%, a thermal conductivity of 0.06 VWm⁰K, a compression strength of 3.0 N/mm² and it is employed for carrying out the masonry and isolation works.

Example 6:

In a stationary vessel 2 whose mixing chamber b has a capacity of 4 m³' having the charging hole c positioned to the upper side, there are introduced the components of the mixture for obtaining the cellular concrete with the apparent density of 500 kg/m³, said components consisting of 200...250 kg of 0 - 1mm grain size sand, 150...200 kg Portland cement with or free of additions consisting of ash and slag, the mixing chamber b is tightly closed relative to the environment and by operating the cock 41, through the arm r there is created a pressure of - 0.4 bar inside the chamber b. The cock 41 is turned off and the mixture is subjected to a rotary motion by rotating the vessel 2 with a rotary speed of 28 rpm for 4 minutes, thereby homogenizing the mixture, thereafter, through the arm s as a result of turning on the cock 42, a gas mixture consisting of argon and air in a 3 ... 1 ratio is introduced into the mixing chamber b, at a pressure of 4.5 bar. The cock 42 is turned off and through the arm t, as a result of turning on the cock 43 , a mixture consisting of 80 I of water, 0.81 AAS, 4 kg of clay, 15 kg of organic binders selected from PAV, CV and BAN is introduced, in the conditions in which the vessel 2 is in a rotary motion. The mixing continues for 10 minutes, then the mixture is decanted through the connecting subassembly B into the mould 30 extant in the discharging chamber a having a pressure of 4.5 bar therein, then by turning on the cock 31, the pressure within the discharging chamber a is slowly equalized with the atmospheric pressure and there takes place the expansion within the mixture mass by increasing the volume of the gas bubbles attached in the mixture by the AAS. The mould 30 with the expanded mixture is taken out of the chamber a and conveyed to a place safe from bad weather, where after 5 -10 hours the cellular concrete may be subjected to the known cutting and palletizing operations.

The concrete obtained this way has an apparent density of 500 kg/m³, a water absorption of 10%, a thermal conductivity of 0.08 WVm⁰K, a compression strength of 4.6 N/mm² and it is employed for carrying out the masonry and isolation works.

Example 7:

In a stationary vessel 2, whose mixing chamber b has a capacity of 4 m³, having the charging hole c positioned to the upper side, there are introduced the components of the mixture for obtaining the cellular concrete with the apparent density of 700 kg/m³, said components consisting of 400 ... 450 kg of 0 - 1 mm grain size sand, 200 ... 220 kg of Portland cement with or free of additions consisting of ash and slag, and the mixing chamber b is tightly closed relative to the environment, and by operating the cock 41, a pressure of - 0.3 bar is created within the chamber b through the arm r. The cock 41 is turned off and the mixture is subjected to a rotary motion by rotating the vessel 2 with a rotary speed of 28 rpm for 3 minutes, thereby homogenizing the concrete, thereafter, through the arm s, as a result of turning on the cock 42, a mixture of gases consisting of argon and air in a 1 ... 1 ratio is introduced into the chamber b, at a pressure of 3.5 bar. The cock 42 is turned off and through the arm t, as a result of turning on the cock 43, a mixture consisting of 88 I of water, 0.6 I of AAS, 4.5 I of clay, 10 kg of organic binders selected from PAV, CV and BAN is introduced, in the conditions in which the vessel is in a rotary motion. The mixing is continued for 10 minutes then the mixture is decanted through the connecting subassembly B into the mould 30 extant in the discharging chamber a, having a pressure of 3.5 bar therein, then, by turning on, the cock 31, the pressure within the discharging chamber a is slowly equalized with the atmospheric pressure and there takes place the expansion within the mixture mass by increasing the volume of the gas bubbles attached in the mixture by the AAS. The mould 30 with the expanded mixture is taken out of the chamber a and conveyed to a place safe from bad weather, where after 5 - 10 hours the cellular concrete may be subjected to the known cutting and palletizing operations.

The concrete obtained this way has an apparent density of 700 kg.m³, a water absorption of 8%, a thermal conductivity of 0.9 VWm⁰K, a compression strength of 9.4 N/mm² and it is employed for carrying out the masonry and insulation works.

Example 8:

The cellular concrete claimed by the invention, obtained in another embodiment, having the compositions of the mixtures presented in examples 1 , 2, 5 and 6 and by using a strength, wear, finishing mixture consisting of 100 ...200 kg of 0 - 1 mm grain size sand, 100 ... 200 kg of Portland cement, 50 ... 100 kg of organic binders, 50 ... 100 I of water, is employed for producing, by casting into the moulds, small blocks of masonry with the surfaces remaining outside the wall consisting of a strength structure with the thickness of 10 ...20 mm, and the interior side consisting of an insulation filling obtained by the laminar casting of the expanded mixture, the plating elements used for insulating the extant walls consisting of a thick strength structure of 10..20 mm that remains outside the wall and an insulation filling which comes into contact with the masonry to be protected.

Claims

1. Process for obtaining the cellular concrete as claimed by the invention, comprising the introducing of the dry solid components of the mixture consisting of sand and Portland cement into a mixing chamber confined within a vessel that is then closed tightly relative to the environment, the mixture also comprising water with additives, said mixture also including a gas entrainer, being subjected to a rotary motion, by rotating the vessel whose axis is preferably positioned in a horizontal plane, with a rotary speed of 15 ... 48 rpm, and finally there taking place the cutting and palletizing, characterized in that it comprises introducing the dry solid components of said mixture into the mixing chamber, then stopping the communication thereof with the environment and creating a pressure having a value of - 0.5 ... - 0.2 bar within the chamber, and rotating the vessel with a rotary speed of 15 ... 48 rpm for 2 ... 6 minutes, then while continuing the rotation, in the mixing chamber there is introduced air or preferably a mixture containing 1 ... 99% by weight air and 99 ... 1% by weight, respectively, argon or only argon at a pressure ranging from 1 to 8 bar and preferably of 2.5 ... 5 bar, followed by introducing, at a pressure of 1 ... 8 bar and preferably of 2.5...5 bar, a mixture of water and additives comprising the gas entrainer and organic binders, where appropriate, the rotation continuing with the same rotary speed of 15 ... 48 rpm for 5 ... 15 minutes, then in a discharging chamber there taking placing the introducing of the air at a pressure of 1 ... 8 bar, said pressure being equal to the pressure value within the mixing chamber, then the mixing chamber is put into communication with the discharging chamber, along a path wherein there is provided a pressure equal to the pressure in the mixing and discharging chambers, finally there taking place the gravity discharging of the mixture into the mould, the equalizing of the pressure in the discharge chamber and in the mixing chamber, respectively, with the atmospheric pressure with a view to expanding the gas bubbles attached in the mixture mass by the gas entrainer, and after the expansion, the mixture mass is discharged from the discharging chamber where the expansion took place and it is let to rest for 5 - 10 hours at the atmospheric pressure or in controlled conditions, followed by the mentioned cutting and palletizing operations.

2. Process for obtaining the cellular concrete obtained in another embodiment, comprising the introducing of the dry solid components of the mixture into a mixing chamber confined within a vessel subjected to rotation and rotating the mixture wherein there was introduced water and additives also containing a gas entrainer together with or without organic binders, within the mixing chamber, with a rotary speed of 15 ...48 rpm for 5 .. 15 minutes, in the conditions in which a pressure higher than 1 bar is created in the chamber, then the mixture is handled into a mould located in a discharging chamber wherein the pressure is equal to the pressure in the mixing chamber and with the pressure along the discharging path, in the conditions in which the upper vessel is stationary, thereafter there taking place the equalizing of the pressure in the discharging chamber with the atmospheric pressure of the mixture wherein the expansion of gas bubbles took place in a mould that is then removed from the discharging chamber and let to rest for 5 - 10 hours at the atmospheric pressure, followed by the cutting and palletizing operations, characterized in that in the mixing chamber there is introduced pressurized air with a pressure value of preferably 5 ... 8 bar, continuing to rotate the vessel with the same rotary speed for 5 ... 15 minutes, then water with the additives and, if necessary, organic binders are introduced with the same pressure into the mixing chamber, while continuing the rotation during the whole period, with the same said rotary speed, then providing a pressure in the discharging chamber and along the said discharging path having a value of 5 ...8 bar, being equal to the pressure in the mixing chamber, then the rotary movement of the vessel is stopped and there takes place the discharge of the mixture into the discharging chamber in the mould, followed by equalizing the pressure in the discharging chamber with the atmospheric pressure.

3. Process for obtaining cellular concrete, in another emboodiment, comprising the introducing of the dry solid components of the mixture into a mixing chamber confined within an upper vessel, then creating a pressure of - 0.2 ... - 0.5 bar in the tightly closed chamber and rotating the mixture with a rotary speed of 15 ... 48 rpm for 2 ... 6 minutes, and then there are introduced, at a pressure of 1 ... 8 bar, gases or preferably a mixture of air and argon or only argon and then the additives including a gas entrainer and the organic binders, if necessary, thereafter the mixture is rotated with a rotary speed of 15 ... 48 rpm for 5 ... 15 minutes, characterized in that the pressure of 1 ... 8 bar in the mixing chamber is slowly reduced with or without an interruption of one minute at each one-bar step, until the pressure reaches the value of the atmospheric pressure, moment when t he gas bubble expansion is completed in the mixture mass and there takes place the mixture discharging at the atmospheric pressure.

4. Installation for obtaining cellular concrete according to the invention, wherein the process according to claim 1 is used, said installation comprising an upper vessel provided with a mixing chamber, having the longitudinal axis preferably located horizontally, sustained in this position by means of some bearings and of a short shaft, to some supports, to the outer side of the vessel there being mounted a toothed wheel of a driving subassembly engaged with a pinion to which the movement is transmitted through a speed reducer from a motor provided with a speed changer, the vessel being provided with a hole that may be tightly closed by means of a flap, characterized in that along the generatrix of the cylindrical shape of the said vessel (2) there are mounted some baffle plates (16) having a preferably semicircular-shaped cavity (f) located in the direction of rotation of the vessel (2), to a pipe connection (1) fastened to the vessel (2) in front of the hole (c) thereof there being secured a nipple (17) of a connecting subassembly (B), in communication with which there is mounted a straightway cock (24), to the lower side of the nipple (17) there being secured an elbow (25) having a lower portion (k) that: partially penetrates into a discharge chamber (a) confined by a lower vessel (23) of a discharging subassembly (C), the elbow (25) having a hole (r) that is closed by a flap (27) articulated to the lower portion (k), in the discharging chamber (a) there being placed on some rollers (28) a mould (30) that may be introduced or withdrawn therefrom through a hole (p) that can be closed by a cover (35) operated by a hydraulic cylinder (33), the upper vessel (2) of a mixing subassembly (A) being sustained by means of the other said bearing (3) to one of the said supports (4) by a tubular shaft (37) of a subassembly (E) for modifying the pressure and for feeding water and additives and organic binders, if necessary.

5. Installation according to claim 4, characterized in that the subassembly (E) for modifying the pressure and for feeding water and additives as well as organic binders, if necessary, has the short tubular shaft (37) axially penetrated by a pipe (38) which also passes through a sealing box (39), a "T"-shaped pipe connection (40) having one of some cocks (41, 42 and 43) mounted on each of the arms (r, s and t) being secured ti the pipe (38), by operating said cocks a negative pressure or an overpressure may be created in the mixing chamber (b), or there may be introduced a mixture consisting of water, additives and organic binders.

6. Installation according to claim 4, characterized in that the connecting subassembly (B) has some gaskets (18 and 26) preferably having an "O" shape in the cross-section, the subassembly having a nipple (17) in whose middle portion there are secured two diametrically opposing pjns to which there is articulated a fork-shaped head (h) of a manoeuvring piece (20) whose handle (i) is articulated to a fixed short vertical support.

7. Installation according to claim 4, characterized in that the upper vessel (2) of the mixing subassembly (A) has two troughs (n) in front of the hole (c), each trough having a 5 ... 10 degrees slope for directing the mixture with a view to being discharged from the mixing chamber (d) through the open hole (c).

8. Cellular concrete as claimed by the invention, obtained by the application of the process as claimed in any one of the claims 1 ... 3, within an installation according to claims 4 ... 7, characterized in that it is constituted by a mixture consisting of 48 ... 62% kg of 0 - 1 mm grain size sand, 48 ... 30% kg Portland cement with or free of additions consisting of ash and slag, 27 ... 18% I of water, 0.3 ... 0.08% AAS, 1 ... 0.6% addition consisting of clay, these values being related to one cubic meter, this cellular concrete having a water absorption of 18 ... 10%, a thermal conductivity of 0.06 ... 0.12% VWm⁰K and a compression strength of 2.4 ... 8.2 N/mm², these values being obtained in the conditions in which the homogenizing pressure is of - 0.5 ... - 0.2 bar, the homogenizing time of 3 ... 4 minutes, there being used a mixture consisting of argon and air in a 3 ... 1 or 1 ... 1 ratio, a mixing pressure of 2.5 ... 5 bar and a mixing time of 5 ... 15 minutes, there being obtained a cellular concrete having a volume weight ranging from 400 to 900 kg/m³.

9. Cellular concrete as claimed by the invention, obtained by the application of the process according to any one of the claims 1 ... 3, within an installation according to the claims 4 ... 7, obtained in another embodiment, characterized in that it is constituted by a mixture consisting of 48 ... 64% of 0 - 1 mm grain size sand, 44 ... 31% Portland cement with or free of additions consisting of ash and slag, 5 ... 0.14% organic binders such as PAV, CV or BNS, preferably BNS, 18 ... 12% water, 0.2 ... 0.1% AAS, 1 ... 0.6% addition consisting of clay, these valued being related to a cubic meter, this cellular concrete having a water absorption of 18 ... 10%, a thermal conductivity of 0.06 ... 0.12% WVm⁰K and a compression strength of 2.4 ... 8.2 N/mm², these values being obtained in the conditions in which the homogenizing pressure is of - 0.5 ... - 0.2 bar, the homogenizing time of 4 ... 3 minutes, there being used a mixture consisting of argon and air in a 3 ... 1 or 1 ... 1 ratio, a mixing pressure of 5 ... 2.5 bar and a mixing time of 5 ... 15 minute, there being obtained concrete with the volume weight ranging from 400 ... 700 kg/m³.

10. Cellular concrete as claimed by the invention, obtained by the application of the process according to claim 3 within in an installation according to claims 4 ... 7 which comprise only the mixture preparation, mixing, followed by gradually reducing the pressure in the mixing chamber to the value of the atmospheric pressure, characterized in that it is constituted from a strength, wear and finishing material consisting of 30 ... 40% of 0 - 1 mm grain size sand, 30 ... 40% Portland cement, 30 ... 40% organic binders, 12 .. 18% water and a filler and insulating material consisting of 40 ... 62% of 0 - 1 mm grain size sand, 30 ...40% Portland cement, 5 ... 1 % organic binders, 12 ... 20% water, there being obtained small masonry blocks by casting into moulds , these blocks having the surfaces remaining outside the wall, constituted from the strength structure and the interior portion from an insulation filling and plating elements that have a surface constituted by a strength structure that remains outside the wall and an insulation filling which comes into contact with the wall they protect, these types of concrete having a thermal conductivity of 0.06 ... 0.08 VWm⁰K.