WO2016182462A1

WO2016182462A1 - A method of manufacturing building elements and a system for manufacturing building elements

Info

Publication number: WO2016182462A1
Application number: PCT/PL2016/000046
Authority: WO
Inventors: Jerzy Haintze; Andrzej Haintze
Original assignee: Jerzy Haintze; Andrzej Haintze
Priority date: 2015-05-08
Filing date: 2016-04-27
Publication date: 2016-11-17
Also published as: PL412276A1

Abstract

The invention relates to a method of manufacturing building elements and a system for manufacturing building elements containing perlite, applicable in building industry. The method of manufacturing building elements consists in taking an amount of earlier-prepared perlite, examining it, weighing it. Next, in appropriately constructed mixers {17) the perlite is mixed with a binder and water in amounts as calculated by a control system (50), building elements are formed in special forming machines (18), are misted in a misting chamber (48} and are subject to curing. The invention moreover covers a system for manufacturing building elements according to the described method.

Description

A method of manufacturing building elements and a system for manufacturing building elements.

The subject-matter of the invention is a method of manuf cturing building elements and a system for manufacturing building elements containing perlite, applicable in building industry.

Polish patent description PL 189779 discloses a method of producing a light building material containing puffed perlite, alkaline-earth metal silicates, hydrophobic agents and possible hardening additives. The method involves making a loose powder mixture, filling a mold therewith, and then compressing and heating it.

The prior art also includes Polish patent applications No. P.319419 and No. P.287006, which present methods of manufacturing building elements from a mix made of gypsum, granulated polystyrene foam and water in strictly defined quantities .

Another known solution is the US patent No. 6368527, which discloses a process for making articles from perlite material that involves grinding raw perlite to a particle size <200 μπι. The ground perlite is mixed with ground silicon carbide powder and moisture added in an amount to achieve a homogeneous mixture having the property of being thixotropic. The mixture is introduced to a mold and agitated to assume the shape of the mold. The agitation is then halted and the material permitted to stiffen to a solidified green molded structure. The molded structure is then removed from the mold and heated at a temperature and time to react the silicon carbide reacts forming carbon dioxide, which induces a foamed structure to the material, and amorphous silicon oxide which fuses with the perlite. The structure is then cooled to yield a resultant fused, foamed perlite article, which may take the form of a building brick, block or panel structure.

Another patent, KR 100845020, presents a method for manufacturing a non-combustible vermiculite panel which includes the steps of: mixing expanded vermiculite, an inorganic binder, expanded perlite, an inorganic blending agent and water to prepare a mixture; putting the mixture into a mold, and cold- pressing the mold to produce a molded product; separating the molded product from the mold and drying it with hot air in a roll type movable press hot blast room; heating and drying the hot-air-dried molded product; and cutting the molded product to produce the non-combustible vermiculite panel.

Patent application No. CN 1267646 discloses a sound- absorbing expanded perlite board and its production process, in which expanded perlite, after being graded according to color and size, is mixed with fine lime powder, water glass and other components, and the mixture is pressed, stoved, cooled and sprayed with hydrophobic agent to obtain a multifunctional expanded perlite product.

Yet another application, CN 1044640, provides a building block of expanded perlite and its preparation method. The method is characterized in that the block consists of 4-14% of expanded perlite, 50-75% of industrial furnace slag, 20-40% of cement and appropriate amount of water. The components are proportioned by weighting, mixed, formed and naturally curing. Volume weight of the block is 628-817 kg/m³, its strength is up to 2,24-3,96 mPa . The adoption of said method can greatly utilize industrial furnace slag, change waste material into things of value, reduce pollution, and has both high social benefits and good economic benefits .

Prior art also knows a processing line for the production of building materials which comprises units for sorting and dosing a mix as well as cement and lime, which are stored in tanks, from where they are conveyed to dosing units and to grinding and mixing units, and then fed to slurry chutes. From slurry chutes they are conveyed to tanks, from where, through slurry and water dosing units, with admixture of aluminum powder, they are conveyed to mixing units and molds.

Another patent, PL 211812, discloses a processing line for the production of building materials. The processing line for the production of building materials, particularly of cellular concrete, is equipped with a dry mixing unit and a wet grinding unit, slurry tanks are located above the building zero level, advantageously 10-20 meters above the ground, and a weighing tank is located between an excess material processing station with a pump and a slurry chute.

Another solution is a utility model No. CN 203622661, which discloses a production line for premixed concrete. The production line comprises a feeding system, a sand making and shaping system, a grading and adjusting system, a screening and dust removing system, an environmental protection system, an electric control system and a conveying system, wherein the feeding system comprises a feeding hopper and a feeding device; the sand making and shaping system is composed of a vertical shaft impact type crusher and a frequency converter; raw materials are controlled by the feeding system to be uniformly fed into the sand making and shaping system; the vertical shaft impact type crusher is used for crushing and shaping the raw materials; then the raw materials enter the screening and dust removing system and the raw materials with great granularity are returned back to the vertical shaft impact type crusher to be crushed and shaped for the second time; the raw materials which are not reasonably graded enter the grading and adjusting system, are graded and adjusted and then enter the screening and dust removing system. According to the production line, a needle sheet shape of coarse aggregate can be reduced; the slump of the premixed concrete and the corrosion to an agitator, a tank car and a pump car are improved; machine-made sand capable of being directly used is also provided so that the production cost of the concrete can be greatly reduced and a production way of the industry is completely changed.

Another application, CN 1386619, reveals a full-automatic production line for making building gypsum blocks from industrial wastes, which is characterized in that between a batching station and a multi-station injection moulding system there are slope-type screw conveyor, hopper-type lifting unit, mixing system, horizontal screw conveyor, another hopper-type lifting unit, microcomputer control center, and control station for batching. The full-automatic circulating system of the production line is composed of shaping moulds, diverter, hydraulic output unit, hydraulic demoulding unit, raise-fall unit and mould locking mechanism. The production line provides for high productivity.

The Applicant, claiming the Polish priority, has filed the patent application No. P.392053 "System of construction elements." In order to manufacture said construction elements it has proved necessary to develop a specific mass containing perlite and a binding agent for said mass; therefore the Applicant has filed, claiming the Polish priorities, two further patent applications, "A method of obtaining a mass for the production of shaped construction elements and a mass for the production of shaped construction elements" No. P.392960, and " method of obtaining a binding agent for a mass for the production of shaped construction elements and a binding agent for a mass for the production of shaped construction elements" No. P.392959. In order to make use of the solutions described in these patent applications it has proved necessary to develop a novel method and a novel production line for the manufacturing of building elements for dry construction of buildings that would take account of the specific properties of a material comprising expanded perlite. The building elements thus obtained will have compressive strength from 1,3 to 1,5 MPa, and the heat-transfer coefficient λ from 0,055 to 0,065. Dimensional accuracy indispensable for providing the self-tightening of the elements as described in document P.392053 should be +/- 1 mm over the length of about 600 mm.

According to the standards, an element obtainable by the present method may be used to construct residential buildings not higher than 12 meters. An essential feature of the building element obtainable by the present method is that it is both a construction element and an insulation element. The prior art knows a limited number of elements capable of performing both these functions, and by the same enabling the construction of single-layer building walls without the need of additional thermal insulation.

The purpose of the present invention was to develop a novel method of manufacturing building elements with a profiled outer surface from a mix containing expanded perlite and a binder, which would eliminate problems related to the lack of homogeneity of perlite as well as guarantee dimensional stability of the manufactured elements.

Moreover, the purpose of the invention was to provide a novel system for carrying out the above method.

A method of manufacturing building elements comprising the steps of producing a mix, filling a mould, forming a building element, is characterized in that the earlier-prepared expanded perlite is taken to fill in measuring containers, and each time physicochemical properties of the perlite in each measuring container are determined, and on the basis of data on the physicochemical properties of the perlite and on the basis of pre-determined models of formulas located in a control system each time an amount of a binder and of water is allotted for each measuring container. Then, the perlite is conveyed from the measuring containers to weighing containers, after which from the respective weighing containers the perlite, the binder and the water in quantities specified in the control system are fed to mixers, where these ingredients are mixed with each other. The mix thus obtained is used to fill in the moulds of a forming machine ensuring a uniform distribution of the material in the moulds, building elements are formed in the forming machine, after which the formed building elements are lifted by means of mechanical ejectors coupled with the matrix and placed on a conveyor belt by means of gripping devices. Next, the building elements are conveyed on the conveyor belt into a misting chamber, the building elements are misted, and then the building elements are stored in a curing chamber.

Preferably, controlled distribution of the material in the moulds of the forming machine is provided by means of appropriate pouring or by conventional fluidization or lance fluidization .

Preferably, the misting is carried out in the misting chamber for 10-20 seconds in ambient temperature during the movement of the conveyor belt carrying the building elements to a stacking tower.

Preferably, the building elements are stored in the curing chamber for two days, at humidity of 80-100% and at temperature of 36-40°C.

Preferably, the building elements are stored in the curing chamber for further three days, at temperature of 38-45°C and at ambient humidity.

A system for manufacturing building elements comprising containers for materials, a weighing device, a control system, a dosing device, a mixing device, a forming device, is characterized in that it includes a perlite hopper containing earlier-prepared expanded perlite, measuring containers for determining physicochemical properties of the perlite, weighing containers for weighing perlite, binder and water, a control system, which each time allots an appropriate quantity of the binder and water individually for each weighed quantity of perlite, a dosing unit for dosing perlite, binder and water into each mixer, mixers for making a mix for building elements from perlite, binder and water, units for conveying the mix into moulds of a forming machine comprising elements for guiding the mix and a system for uniform distribution of the material in the moulds, forming machines with a system for uniform distribution of the material in the moulds, units for removing building elements from the moulds of the forming machine by means of ejectors mechanically coupled with the motion of the matrix, sets of gripping devices with a pneumatic drive, a misting chamber, a stacking tower, a curing chamber.

Preferably, the number of measuring containers for determining physicochemical properties of perlite corresponds to the number of mixers and the number of moulds in the forming machine.

Preferably, additional elements for uniform distribution of the mix in the moulds are fluidization lances.

Preferably, the matrix of the forming machine is movable.

Preferably, the ejectors' drive is coupled with the motion of the matrix.

The system of construction elements disclosed in the patent application P.392053 must be made with very good dimensional precision and compositional accuracy and with due account taken of physicochemical parameters such as thermal insulation. The method and system disclosed in this application guarantee that these requirements are fulfilled in an economically-justified way, even though the starting material - perlite - is a material with unstable properties.

Moreover, the disclosed method and system provide the possibility of manufacturing ceramic building elements at ambient temperature; the step of heating or firing that could cause shrinking and, consequently, change of dimensions, has been eliminated.

With the internal transport paths maximally shortened, it was possible to obtain a maximum concentration of the production means .

The subject-matter of the solution has been presented in the drawing, in which:

Fig. 1 presents a block diagram of the system for manufacturing building elements according to the invention, Fig. 2 presents a front view of a portion of the system for manufacturing building elements, whose last shown element is the conveyor belt,

Fig. 3 presents a perspective view of a portion of the system for manufacturing building elements without the conveyor belt, Fig. 4 presents two views of the set of gripping devices with a building element,

Fig. 5 presents a plunger's ejector unit,

Fig. 6 presents a drive of the plunger's ejectors,

Fig. 7 presents a drive unit of the matrix' ejectors.

A method of manufacturing building elements according to the diagram presented in Fig. 1 comprises several steps. The first is the step of determining physicochemical properties of the perlite. Measuring containers 1 are filled with earlier- prepared expanded perlite stored in a hopper 46, and physicochemical parameters are measured, especially perlite bulk density. Next, based on the data on the physicochemical properties of the perlite and on the basis of pre-determined models of formulas located in a control system 50, each time an amount of a binder and of water is allotted for each measuring container 2 filled with perlite.

The technology requires a specific exactness of quantity measurement. The formula is each time adapted to the quality (bulk density) of the perlite. Owing to great diversity of perlite it may happen that each container is filled with perlite of different density/weight. For this reason, instructions sent from the control system 50 may indicate different amounts of the binder and water for each mixer 17. As weighing containers to weight the perlite and the binder are employed silos mounted on a suspension with tensometric sensors. The perlite is fed into the respective silos by screw conveyors 11, 12, 13, 14, 15, 16 terminated with flap electrovalves . Pouring the perlite goes on until the flaps close and the motor of the conveyor is off. The binder is fed into the respective silos by screw conveyors 4, 5, 6, 7, 8, 9 terminated with flap electrovalves. To weight/measure out the water a pipe system is used (not shown in the drawing) with a pump and an electrovalve, while a pulse water meter serves as a measuring system. The allotted amount of water is then conveyed through the pipe into the mixer 17. The allotted amounts of the perlite and the binder are transported to the mixers 17 through gravity-flow pipelines 47. For example, with six mixers 17, there are eighteen weighing containers: six for the water, six for the binder, and six for the perlite. The drum of the mixer 17 has an inlet on top, which, after 180° rotation of the drum, becomes an outlet on the bottom. The top inlet is covered with a large flap pneumatically slidable up and down. The drum of the mixer 17 forming part of the production line according to the invention is immobile when the ingredients are mixed, the mix being mixed by blades. Once the mixing is finished, the flap is slightly lifted, after which the drum is rotated 180 degrees around its axis, which is at the same time the axis of rotation of the shaft on which the blades are mounted, gravitationally pouring out the obtained mix. The necessary condition of carrying out the process of manufacturing a building block is water- tightness of the mixing drum. Water-tightness is indispensable, because after pouring out the contents the inside of the drum is rinsed with pressured water to prepare the unit for receiving the next batch of the material for mixing.

The blades are washed by rinsing, and at the same time, during the rinsing, a next portion of perlite is introduced for making another batch of elements. The mix obtained in the mixer unit 17 is conveyed through chutes 21 into the moulds of the forming machine 18. Chutes 21 are gravitational transport elements. Owing to the constant contact with fresh forming mix, the surfaces of the chutes 21 must be made of a very highly anti- adhesive material. An essential feature of this transport is providing a momentary transport connection between a mixer 17 and a mould of the forming machine 18 and moving the chute out of the range of the forming machine 18 during the cycle of forming a building element.

The terminal end of the chute 21 is equipped with compressed air lances (not shown) , which are submerged into the mix, providing the effect of fluidization of the mix in the mould. Lances are close-end inflexible pipe segments with a number of holes on their side surface. Compressed air is introduced through them into the mix, fluidizing it, and the fluffed mix forms a level surface. After the operation, the lances are withdrawn from the mix, and once they are withdrawn the process of mixing starts. Even distribution of the mix can also be obtained by conventional fluidization.

Chutes can be substituted with a mechanical transport system of intermediate containers with a controllable pouring outlet. It comprises a charging hopper and a horizontal transmission system. The volume of the charging hopper is such that it easily receives the volume of the mix prepared by the mixer 17 and destined for forming one element 25. The hopper is a cuboid, close in shape to the moulding box, open from the top, while the bottom consists of two slanting flaps with rotation axes parallel to the longer sides of the cuboid. In its starting position the hopper is located directly under the outlet of the corresponding mixer. The bottom is closed, namely the flaps are in contact, with their edges parallel to the axes of the hinges touching at an angle. After filling, the hopper moves along the transmission system towards the moulding box and stops once the hopper and the moulding box fully overlap. A mechanism actuates the flap valve and the whole mix is gravitationally poured into the moulding box. Such system of the flap valve provides for a sufficiently good distribution of the mix within the moulding box. Next, the hopper is retracted to its starting position.

It is very important for the present solution that in the production line is employed an appropriately constructed forming machine. The forming machine 18 is composed of a vertical steel frame, a middle belt for mounting moulding boxes, movable beams - upper and lower, an actuating system, sliders for positioning the vertical motion of the beams and guaranteeing they stay parallel to each other. The beams are additionally equipped with stands for the matrices and for the plungers. The matrices' stands are equipped with actuators for activating the ejectors (Fig. 7) .

The beams of the forming machine 18 are set in motion by mechanical actuators (lead screws) mounted on both sides of the middle belt for mounting moulding boxes, outside of the range destined for mounting moulding boxes. Lead screw nuts are located in side terminal ends of the beams. The controlled synchronization of work of the actuators provides for the parallel operation and the possibility to precisely position the beams relative to each other, which is the necessary condition for correctly forming the building elements 25. Thanks to such operation, a porous material is obtained (open microchannels ) . The work cycle starts with the filling of the mould with the mix, at the moment when the matrix is in its lowest position and the plunger at its topmost position. Next, the plunger is brought down to the position in which it closes the mould while the matrix is brought up. The plunger and the matrix are actuated simultaneously, which gives the effect of simultaneous compression of the mass from the top and from the bottom and provides for dimensional stability of the elements. After forming, the plunger is lifted to its starting position and the matrix makes an additional upward motion to dislocate the formed element pushing it above the upper surface of the moulding box. Gripping device plates 26 are inserted between the formed elements 25, and the elements 25 are moved outside of the forming machine 18. The number of moulds of the forming machine 18 corresponds to the number of mixers 17. In order to decrease the wear of the mechanical actuators responsible for the precision of the manufactured elements (height dimension of the element dependant on the distance between the matrix and the plunger during the forming stroke) a hybrid drive is used, which consists in using both a mechanical drive and a hydraulic drive. In this case, the mechanical drive performs the stabilizing-positioning function while the hydraulic drive entirely carries the direct load, which considerably increases the failure-free working life of the forming machine 18. In order to correctly form the elements it is necessary to provide a pressure force on the single element of about 20 t on both sides. Because of the specific properties of the element (self-tightening) another operation is necessary - getting out of the grip produced at the contact surfaces with the matrix. A system of ejectors placed in pockets of the matrices and the plungers is used. The ejectors are mechanically coupled with the motion of the matrices. The plunger's ejector (Fig. 5) is composed of a plate 29 nested in the pocket of the plunger with pilot bars 30 in its body 28. The plunger's ejectors are driven (Fig. 6) by two springs 34. The springs 34 are stretched in the course of compressing the mass (forming) and are actuated at the moment the plunger is lifted after the element 25 is completely formed. The matrix's ejectors are located in the matrix pockets and are actuated during the last phase of pushing the formed element 25 out of the mould of the forming machine 18. The drive originates from the catch mechanism {Fig. 7) composed of a screw 44 for regulating the advancement of the ejectors' plates and one arm of a first-class lever 45 and of a lever system made of the other arm of the first-class lever 45 and a slider 42 with a pilot sleeve of the stabilizer beam. Thus the movement of the ejectors is mechanically coupled with the movement of the matrix. The formed elements 25 are pushed out of the moulds by the movement of the matrix and of the ejectors, and then they are placed on the conveyor belt 19 by means of pneumatic grippers. A gripper is formed by four plates 26 clasping the longer sides of the element 25 collected from the forming machine 18. The plates 26 are fixed in pairs through a hinge lever 24 system with pneumatic actuators 22, which provides for a tight adhesion of the plates 26 and a suitable pressure force to provide a sufficiently tight grip. The actuators are mounted on a shared beam 23 structurally connected with a system enabling to move the elements in at least two directions. This results from the need to take out the manufactured elements 25 from the forming machine 18 and to place them on the transport sheets on the conveyor belt 19.

The elements 25 on the transport sheets on the conveyor belt 19 are moved into the misting chamber 48 for a predetermined period of time, at humidity of 100% and at ambient temperature. The misting chamber 48 is a confined space with a fitted opening, through which are introduced the elements 25 lying on the transport sheets on the conveyor belt 19. Inside the misting chamber 48 water is sprayed to maintain a water aerosol therein.

The length of the chamber is designed depending on the intended speed of the conveyor belt 19 carrying the elements 25. The misting chamber 48 is located between the gripping devices unit collecting the elements 25 from the forming machine 18 and the stacking tower (not shown) . When the elements are staying in the misting chamber 48, through the microchannels in the element's material water is delivered to the binder present in the mix from which the elements 25 have been made.

The maximal moisturizing of the elements is obtained by way of misting {water aerosol - 100% humidity) for 10 - 20 seconds at ambient temperature during the movement of the conveyor belt 19 carrying the elements 25 into the stacking tower, which enables high storage.

It should be mentioned that the contact surface between the building elements, according to the Polish patent application P- 392053, is profiled and therefore the evaporation surface is increased. Moreover, the element according to the above patent application has projecting parts, which are especially exposed to quick evaporation of water - these are tops and edges of the "green" pre-prepared building element 25. Ensuring the sufficient water content in the element 25 is necessary for obtaining appropriate final properties, especially appropriate hardness .

The last stage of manufacturing the building element is curing in the curing chamber (not shown) , into which the building elements are conveyed from the stacking tower containing a high allowance of water. They are stored in the curing chamber for five days, and during the first two days a light flow of air is used to regulate humidity in the range of 80-100% and temperature in the range of 36~40°C, resulting in 70-80% of final resistance. For the next three days the conditions in the curing chamber are changed to such as would allow evaporation of the excess water from the elements by providing a flow of maximally dry and warm air, at temperature of 38-45°C, at ambient humidity. During this operation the elements obtain 90-95% of their final resistance. Final resistance, reached 14-20 days after manufacturing of the elements, according to the presently described method, is 1,3- 1,5 MPa, whereas uncured elements have resistance of only 0,8- 1,0 MPa. Appropriate moisturizing and drying is therefore very important for this type of building element.

The curing chamber is a room of an industrial-hall size, its cubature being adapted to the production size, and provided with a high storage system. The size of the racks and the distances between the columns amount to multiplicity of the size of a single element. The chamber is divided into sectors adjusted to the daily production size. The sectors are separated with partitions which allow keeping individual environmental conditions (temperature and humidity) . It is possible to carry out the full curing process within a single sector. As it follows from the above, the curing chamber must have a suitable thermal insulation and must be equipped with installations: ventilating, heating-and-humidifying, and measuring.

A working example of the method for manufacturing building elements

In this example, six elements 25 are made in a single work cycle. Realisation of the method according to the invention is preceded by stages of preparation of the binder and the puffed perlite, which are not part of this invention. Expanded perlite with appropriately selected particle sizes is transported by bucket conveyors from the perlite hopper 46 into six measuring containers having volume of 1,5 m³ each, in order to determine its bulk density, and the data obtained during the process of determining bulk density are transferred to the control system. Determination of bulk density is a particularly important part of the process, for the sake of maintaining homogeneity of the mass. Measurements taken at this stage are a basis for further allotting the amounts of the individual ingredients indispensable in the process. Next, the expanded perlite is transported into silos by means of screw conveyors 11, 12, 13, 14, 15, 16 terminated with flap electrovalves . The binder is fed into the respective silos by screw conveyors 4, 5, 6, 7, 8, 9 terminated with flap electrovalves. To weight/measure out the water a pipe system is used (not shown in the drawing) with a pump and an electrovalve, while a pulse water meter serves as a measuring system. The allotted amount of water is then conveyed through the pipe into the mixers 17.

The earlier prepared ingredients of the mix in the amounts as allotted by the control system 50 are transported to the mixer unit 17: the weighed out amounts of perlite and binder are transported through gravity-flow pipelines 47. In the mixers 17 a mix is made for filling the moulds of the forming machine 18. In this working example, the amounts of the ingredients in the individual mixers are as follows:

Water Perlite Binder

Mixer I : 6,00 kg 6,80 kg 9,00 kg

Mixer II: 6,50 kg 5,90 kg 9,50 kg Mixer III: 5,50 kg 7,70 kg 8,50 kg

Mixer IV: 6,50 kg 5,90 kg 9,50 kg

Mixer V: 5,50 kg 7,70 kg 8,50 kg

Mixer VI: 6,00 kg 7,70 kg 8,50 kg

The ingredients in the individual mixers 17 are mixed thanks to the motion of ribbon rotors at a horizontal axis, with speed of about 120 rpm during about 10 seconds. The mix so prepared is transferred from the mixers 17 to the moulds of the forming machine 18 through chutes equipped with compressed air lances. After the six moulds of the forming machine 18 are full, the lances are submerged into the mix for 5 seconds to pump air compressed to 2,5 atmospheres, which allows for the fluidization effect to appear, after which the lances are retracted and forming of the elements 25 is carried out. As a result of the forming process, system module elements are obtained, of a quality enabling the continuation of the further stages of the method. The forming is carried out with the pressure of the matrix and the plunger of 20 t on each single element. The duration of one cycle is about 1,5 minutes. The formed elements 25 are lifted by mechanical ejectors of the matrix and then by means of gripping devices are placed on transport sheets on the conveyor belt 19. In the next stages of the method, the treated elements 25 remain on the sheets on the conveyor belt 19. The transmission system, after the formed elements are placed on the sheets on the conveyor belt, is composed of many elements: sheets, manipulators, chain feeders, tiltable chain feeders, reversible chain feeders, belt conveyors, sheet stackers, feeders of stacked sheets, stacking and de-stacking towers, turning gears, a wrapping unit, a packing unit.

During the transmission, the elements 25 are additionally subjected to the process of moisturizing by way of misting, which takes place in the misting chamber 48 at humidity of 100% over 15 seconds at ambient temperature during the movement of the conveyor belt 19 carrying the elements 25 into a stacking tower, which enables high storage.

Next, the elements 25 are conveyed on stacked sheets into a multilevel storeroom - a curing chamber, for the purpose of being cured. They are stored in the curing chamber for five days, and during the first two days a light flow of air is used to regulate humidity in the range of 80-100% and temperature in the range of 36-40°C, resulting in 70-80% of final resistance. For the next three days the conditions in the curing chamber are changed by providing a flow of maximally dry and warm air, at temperature of 38-45°C. During this operation the elements obtain 90-95% of their final resistance. Final resistance, reached 14-20 days after manufacturing of the elements, according to the presently described method, is 1,3-1,5 Pa. The finished product, after the production processes end, is packed and transported to a warehouse.

A working example of the system for manufacturing building elements

The system for manufacturing building elements according to the invention has many components. The first of them is a perlite hopper 46, having volume of 13 m³, containing earlier-prepared expanded perlite, from which the perlite is conveyed to six measuring containers 1, having volume of 1,5 m³, which serve to determine physicochemical properties of the perlite. The data on perlite' s bulk density are sent to the control system 50. The system moreover comprises screw conveyors for transporting the perlite and the binder to the weighing containers. In the working example, the weighing container is a silo with the following parameters: height about 1250 mm, perlite inlet diameter about 250 mm. The expanded perlite is transported into the silos by means of screw conveyors 11, 12, 13, 14, 15, 16 terminated with flap electrovalves . The binder is fed by screw conveyors 4, 5, 6, 7, 8, 9 terminated with flap electrovalves. In the corresponding weighing containers 20, 52, the binder and the water are weighed out. To weight/measure out the water, a pipe system is used (not shown in the drawing) with a pump and an electrovalve, while a pulse water meter serves as a measuring system. The allotted amount of water is then conveyed through the pipe into the mixer 17. The allotted amounts of the perlite and the binder are transported to the mixers 17 through gravity- flow pipelines 47.

In the working example, with six mixers 17, there are eighteen weighing containers 2, 20, 52: six for the water, six for the binder, and six for the perlite. The drum of the mixer 17 has an inlet on top, which, after 180° rotation of the drum, becomes an outlet on the bottom. The top inlet is covered with a large flap pneumatically slidable up and down. The drum of the mixer 17 forming part of the system is immobile when the ingredients are mixed, the mix being mixed by blades. The mixing drum is water-tight. The mix obtained in the mixers 17 is conveyed through the chutes 21 into the moulds of the forming machine 18.

The system moreover includes a unit for feeding the mix into the moulds comprising elements for conveying the mix in the form of chutes and a system for uniform distribution of the mix in the mould; the elements serving to uniformly distribute the mix in the moulds are fluidization lances. The chutes 21 are gravitational transport elements. Owing to the constant contact with fresh forming mix, the surfaces of the chutes 21 must be made of a very highly anti-adhesive material. An essential feature of this transport is providing a momentary transport connection between a mixer 17 and a mould of the forming machine 18 and moving the chute out of the range of the forming machine 18 during the cycle of forming a building element 25. Lances are close-end inflexible pipe segments with a number of holes on their side surface. Compressed air flows through them into the mix, fluidizing it, and the fluffed mix forms a level surface. After the operation, the lances are withdrawn from the mix, and once they are withdrawn the process of mixing starts.

The system moreover includes a six-box forming machine 18, which is composed of a vertical steel frame, a middle belt for mounting moulding boxes, movable beams - upper and lower, an actuating system, sliders for positioning the vertical motion of the beams and guaranteeing they stay parallel to each other. The beams are additionally equipped with stands for the matrices and for the plungers. The matrices' stands are equipped with actuators for activating the ejectors.

The beams of the forming machine 18 are set in motion by mechanical actuators (lead screws) mounted on both sides of the middle belt for mounting moulding boxes, outside of the range destined for mounting moulding boxes. Lead screw nuts are located in side terminal ends of the beams. The controlled synchronization of work of the actuators provides for the parallel operation and the possibility to precisely position the beams relative to each other, which is the necessary condition for correctly forming the building elements 25. Both the plunger and the matrix of the forming machine 18 are equipped with units for removing the building elements from the moulds by means of ejectors. The matrix' ejectors are mechanically coupled with the motion of the matrix, the matrix of the forming machine 18 being movable. Moreover, the system includes six gripping devices with a pneumatic drive. A gripper is formed by four plates 26 clasping the longer sides of the element 25 collected from the forming machine 18. The plates 26 are fixed in pairs through a hinge lever 24 system with pneumatic actuators 22, which provides for a tight adhesion of the plates 26 and a suitable pressure force, to provide a sufficiently tight grip. The actuators are mounted on a shared beam 23 structurally connected with a system enabling to move the elements in at least two directions.

The grippers carry the building elements 25 to the conveyor belt 19, on which they are further transported to the misting chamber 48.

The misting chamber 48 is located between the gripping devices unit collecting the elements 25 from the forming machine 18 and the stacking tower (not shown) . In the working example, the length of the misting chamber 48 is 3,5 m. The misting chamber 48 is a confined space with a fitted opening, through which are introduced the elements 25 lying on the sheets on the conveyor belt 19.

The system also incorporates a stacking tower, which is a device available in the trade.

The last element of the system is a curing chamber, which is a room of an industrial-hall size, its cubature being 2 000 m³. The curing chamber is provided with a high storage system. The size of the racks and the distances between the columns amount to multiplicity of the size of a single element. The chamber is divided into five sectors adjusted to the daily production size, which in the working example is 3 500 pieces. The sectors are separated with partitions, which allow keeping individual environmental conditions (temperature and humidity) . It is possible to carry out the full curing process within a single sector. The curing chamber has a thermal insulation and is equipped with installations: ventilating, heating-and- humidifying, and measuring.

In the working example, with the disclosed system, 750 000 building elements 25 were manufactured over one year, in a two- shift work regime.

List of references

1 measuring containers

2 perlite weighing containers

3 binder tank

4 screw conveyor

5 screw conveyor screw conveyor

screw conveyor

perlite distributing container

screw conveyor

mixer unit

forming machine

conveyor belt

set of binder weighing containers

unit for conveying the mix into the moulds (chutes, charging hoppers)

pneumatic actuators unit

actuators' support beam

hinge lever

building element

gripping device plate

construction bar

plunger body

ejector plate

pilot bar

upper plate of the ejector's stand

screw for regulating stress on the spring

spring upper socket spring

spring lower socket

plunger support plate

screw for regulating advancement of the ejector plate bar's pilot sleeve

pushers of bars of the ejector plates

return spring

ejectors' parallel action stabilizer beam

slider with a pilot sleeve of the stabilizer beam body

screw for regulating advancement of ejectors' plates first-class lever

perlite hopper

gravity-flow pipelines

misting chamber

control system

measurement and control signals

water weighing containers

Claims

Patent claims

1. A method of manufacturing building elements comprising the steps of producing a mix, filling a mould, forming a building element, characterized in that

- earlier-prepared expanded perlite is taken to fill in measuring containers (1) and each time physicochemical properties of the perlite in each of the measuring containers (1) are determined;

- on the basis of data on the physicochemical properties of the perlite and on the basis of pre-determined models of formulas located in a control system (50) each time an amount of a binder and of water is allotted for each measuring container (1) ;

- the perlite is conveyed from the measuring containers to weighing containers (2);

- from the respective weighing containers (2, 20, 52) the perlite, the binder and the water in quantities specified in the control system {50} are fed to mixers {17), where these ingredients are mixed with each other;

- a mix thus obtained is used to fill in the moulds of a forming machine (18) ensuring a uniform distribution of the material in the moulds ;

- building elements (25} are formed in the forming machine

(18) ; - the formed building elements are lifted by means of mechanical ejectors coupled with the matrix being simultaneously separated from the plunger by plunger ejectors, and are placed on a conveyor belt (19) by means of gripping devices;

- the building elements (25) are conveyed on the conveyor belt (19) into a misting chamber (48) ;

- the building elements (25) are misted in the misting chamber ( 8) ;

- the building elements (25) are stored in a curing chamber.

2. A method according to claim 1 characterized in that controlled distribution of the material in the moulds of the forming machine (18) is provided by means of appropriate pouring or by conventional fluidization or lance fluidization.

3. A method according to claim 1 characterized in that the misting is carried out in the misting chamber (48) for 10-20 seconds in ambient temperature during the movement of the conveyor belt (19) carrying the building elements (25) to a stacking tower.

4. A method according to claim 1 characterized in that the building elements (25) are stored in the curing chamber for two days, at humidity of 80-100% and at temperature of 36-40°C.

5. A method according to claim 1 characterized in that the building elements (25) are stored in the curing chamber for further three days, at temperature of 38- 5 °C and at ambient humidity.

6. A system for manufacturing building elements comprising containers for materials, a weighing device, a control system, a dosing device, a mixing device, a forming device, characterized in that it includes: a perlite hopper (46) containing earlier-prepared expanded perlite;

- measuring containers (1) for determining physicochemical properties of the perlite;

- weighing containers (2, 20, 52) for weighing perlite, binder and water;

a control system (50} which each time allots an appropriate quantity of the binder and water individually for each weighed quantity of the perlite;

- a dosing unit for dosing perlite, binder and water into each mixer;

- mixers (17} for making a mix for building elements from perlite, binder and water;

- units (21) for conveying the mix into moulds of a forming machine (18) comprising elements for guiding the mix and a system for uniform distribution of the material in the moulds;

forming machines (18) with a system for uniform distribution of the material in the moulds;

- units for removing building elements (25) from the moulds of the forming machine (18) by means of ejectors mechanically coupled with the motion of the matrix;

- ejector units for separating the building element (25} from the plunger;

- sets of gripping devices with a pneumatic drive;

- a misting chamber (48);

- a stacking tower;

- a curing chamber.

7. A system according to claim 6 characterized in that the number of measuring containers (1) for determining physico-chemical properties of the perlite corresponds to the number of mixers (17) and the number of moulds in the forming machine (18 } .

8. A system according to claim 6 characterized in that additional elements for uniform distribution of the mix in the moulds are fluidization lances.

9. A system according to claim 6 characterized in that the matrix of the forming machine (18) is movable.

10. A system according to claim 6 characterized in that the ejectors' drive is coupled with the motion of the matrix.