RU2581068C1 - Method of producing foam concrete and apparatus therefor - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: group of inventions relates to production of foam concrete. Method of producing foam concrete, comprising preparation of a process mixture by mixing concentrate of foaming agent, water, binder, filler, additives and aeration of a mixture of compressed air in a mixer, obtaining foamed concrete is carried out continuously in three steps: first step comprises mixing-activating binding components with water, filler and additives in a mixer-activator at a rate of 1,500-3,000 1/min of working tool with cavitation effect until liquid-solid dispersion of binding materials in thixotropic metastable state with reduction of viscosity of up to 50-500 Pa·s in another mixer-activator mixing-activation of concentrate of foaming agent with addition of water to obtain a liquid-liquid dispersion of a foaming agent in thixotropic metastable state with reduction of viscosity of up to 10-200 Pa·s, at second step in a mixer-aerator with rotation speed of working tool of 1,000-1,500 1/min mixing continuous streams of both previously activated dispersions with aeration with compressed air at excess pressure 0.25-2.5 MPa, and at third stage foamed mass obtained in mixer-aerator is continuously fed into channel of foam mass-structure forming agent composed of diffuser, combining continuous transfer of foamed mass in framework and its flawless structuring of free motion under action of pressure difference of 0.25-2.5 MPa at inlet channel and 0.01-0.1 MPa at its output with limitation of maximum linear speed of flow and minimum time of foamed mass in channel. Apparatus for producing foam concrete in paragraph 1 includes a mixer-activator of binding components with filler and additives, a mixer-activator of foaming agent, a mixer-aerator of foamed mass at excess pressure, foam mass-structure forming agent representing cylindrical channel carrying foamed mass in framework, automatic control of individual devices and unit, as well as automatic dispensers of all components of foamed mass, accumulating capacity of activated dispersions, pumps, air compressor, dispenser of binder components, dispenser aggregate, batcher accelerators, plasticisers and other additives, water dispenser connected with mixer-activator binding components with filler and additives, which is connected in turn with storage tank activated dispersion of binding materials and then through pump binder is connected with mixer-aerator foamed mass, which through foam mass- structure forming agent is supplied into framework, simultaneously batcher concentrate foaming agent and water dispenser connected with mixer-activator of foaming agent, which is connected in turn with storage tank activated dispersion of foaming agent and then through pump foaming agent is connected with mixer-aerator of foamed mass, batcher reinforcing additives is connected to input and/or output channel foam mass-structure forming agent. Invention is developed in subclaims.

EFFECT: technical result is higher homogeneity of structure, strength, low heat conductivity of foam concrete.

7 cl, 7 dwg

Description

The present invention relates to the field of production of foam concrete in various sectors of construction, in particular construction and repair: residential and industrial buildings and structures, the foundation of objects of transport infrastructure (roads, railways, runways, cargo areas of airports, sea and river ports, drilling sites, city streets and squares, etc.), thermal insulation and strengthening of underground structures: (tunnels, mine workings, pipelines, culverts, bridges at mooing, etc.). Of particular importance, the invention gets to obtain light up to 400 kg / ^m3 and a super easy to 200 kg / ^m3 foam concrete in climates with extreme conditions construction: permafrost zone, distending water saturated soils, large temperature gradients, etc.

Known methods for producing foam close to the claimed in its technical essence and the achieved result: SU 461916 (CL C04B 21/10. B28C 5/00, publ. 28.02.1975) (D1); RU 2099313 (CL C04B 38/10, B28B 1/50, publ. 12/20/1997) (D2); RU 2197380 (CL B28C 5/38, publ. 09/10/1999) (D3).

A method of preparing a porous concrete mixture (D1) consists in mixing the components in a concrete mixer with the introduction of an air-entraining additive, and in order to reduce the bulk density of concrete and increase its uniformity during mixing, compressed air is supplied to the mixture under a pressure of 0.15-0.2 MPa.

The disadvantages of the known method (D1) are the cyclic (periodic) mode of operation, low equipment productivity, high labor costs, a narrow range of foam concrete density of 600-1200 kg / m ³ , high heterogeneity and imperfection of the pore structure, high thermal conductivity and low mechanical strength of the product.

A method of manufacturing products from foam concrete (D2) involves preparing the mixture by co-grinding a binder and a mineral aggregate in a vibratory mill with the simultaneous introduction of water and a pore-forming additive. In the process of grinding in the mixture, excess pressure is created due to the heating of the foam mixture and additional air injection, increasing from 0 to 0.25 MPa by the beginning of unloading of the mixture into the mold.

The disadvantages of the known method (D2) are the cyclic (periodic) mode of operation, low equipment productivity, high labor costs, a narrow range of foam concrete density (light and ultra-light foam concrete are not available), high heterogeneity and imperfection of the pore structure, high thermal conductivity and low mechanical strength of the foam concrete.

A method of preparing a foam concrete mixture (D3) involves preparing a process mixture by mixing a surfactant, water, cement and a siliceous component. The process mixture is poured with compressed air in a mixer having an ejector, a rotor with blades mounted to rotate and form a rarefaction zone by repeatedly passing the process mixture through the ejector and the rarefaction zone, with the formation of many small air pores, the air pressure in which is equal to the pressure in the mixer . The selection of the porous process mixture is carried out through an opening in the lower part of the mixer.

The disadvantages of the known method (D3) are the cyclic (periodic) mode of operation, low equipment productivity, high labor costs, a narrow range of foam concrete density (light and ultra-light foam concrete are not available), high heterogeneity and defectiveness of the pore structure, high thermal conductivity and low mechanical strength of the foam concrete.

The technical result, which is achieved by the claimed method of producing foam concrete, is a high-performance continuous mode of foam concrete preparation, a significant increase in the physico-mechanical characteristics and consumer properties of foam concrete due to an increase in the uniformity and defect-free structure, including a decrease in thermal conductivity, and an increase in mechanical strength, significant the expansion of the range of density of foam concrete towards the lower border to 70 kg / m ³ (ultralight foam concrete), reducing e labor costs due to the high degree of mechanization and automation.

To achieve the specified technical result, the method for producing foam concrete is carried out continuously in three stages, while the first stage is mixing-activating the binder components with water, aggregate and additives in the mixer-activator with a speed of 1500-3000 1 / min rotation of the working body with a cavitation effect up to to obtain a liquid-solid dispersion of binders in a thixotropic metastable state with a decrease in viscosity to 50-500 Pa · s, in another mixer-activator, mixing and activation of the foaming concentrate are carried out with the addition of water to obtain a liquid-liquid dispersion of the foaming agent in a thixotropic metastable state with a decrease in viscosity to 10-200 Pa · s, at the second stage in a mixer-aerator with a speed of rotation of the working bodies 1000-1500 1 / min are mixing continuous flows of both previously activated dispersions with their simultaneous aeration with compressed air at an excess pressure of 0.25-2.5 MPa, and in the third stage, the foam mass obtained in the mixer-aerator is continuously fed into the channel of the foam mass-structure former in the form of a diffuser, involving continuous transportation of foam mass into the formwork and its defect-free structuring in the free movement mode under the action of a pressure difference of 0.25-2.5 MPa at the channel inlet and 0.01-0.1 MPa at its exit while limiting the maximum linear flow rate and the minimum the residence time of the foam mass in the channel, while the first stage is mixing-activating the binder components with water, aggregate and additives in the mixer-activator with a cavitation effect to obtain a liquid-solid dispersion of binders in thixotropic th metastable state with a decrease in viscosity, in another mixer-activator, the foaming concentrate is mixed-activated with the addition of water until a liquid-liquid dispersion of the foaming agent is obtained in a thixotropic metastable state with a decrease in viscosity, in the second stage, continuous flows are mixed in the mixer-aerator at positive pressure of both previously activated dispersions with their simultaneous aeration with compressed air, and in the third stage, the foam mass obtained in the mixer-aerator is continuous but it enters the channel of the foam mass-forming agent in the form of a diffuser, combining the continuous transportation of foam into the formwork and its defect-free structure in free motion under the influence of the pressure difference at the inlet and outlet of the channel while limiting the maximum linear flow velocity and the minimum residence time of the foam mass in the channel.

The proposed continuous method for producing foam concrete, taking into account the above description, will be briefly referred to hereinafter as “activation-aeration-structuring”.

A common similarity of the above methods (D1-D3) with the proposed method for producing foam concrete is the use of compressed air.

Significant differences of the proposed method for producing foam concrete from known cyclic methods, including (D1-D3):

- continuous mode of foam concrete preparation,

- separate mixing-activation of the dispersion of binders with water, filler and additives and the dispersion of the foaming agent in the activator mixers to obtain thixotropic metastable states of these dispersions at the preparation stage [1],

- continuous mixing with simultaneous aeration of the activated liquid-liquid dispersion of the foaming agent and the liquid-solid dispersion of binders with aggregate and additives in metastable thixotropic states of both dispersions,

- combining the continuous transportation of foam mass into the formwork in the free movement mode under the influence of the pressure difference with defect-free structure of the foam mass (controlled growth of air bubbles without destroying the interstitial partitions) during its relaxation with a gradual decrease in pressure in the foam mass-structure former in the form of a diffuser with a variable cross-sectional profile along the length that provides the specified restrictions on the maximum linear speed and minimum residence time of the foam mass in the channel.

Closest to the proposed invention in terms of essential features is the method (D3) (prototype).

Installation for implementing the proposed method for producing foam concrete is the technological core of many different complete sets of equipment to obtain:

- various foam concrete products with stationary sets of equipment in the factory, including blocks and panels,

- monolithic foam concrete with mobile sets of equipment in construction conditions.

In both cases, the foam concrete mixture (foam mass) prepared in the proposed installation is poured into the formwork and maintained in it, without applying mechanical influences, until the foam concrete reaches its standard strength.

Known installations for producing foam concrete, close to the claimed in its technical essence and the achieved result: RU 2136492 (class B28C 5/38, publ. 09/10/1999) (D4); RU 2200090 (class B28C 5/38, publ. 02.20.2001) (D5).

The installation for the preparation of foam concrete mixture (D4) performs continuous preparation of the foam concrete mixture in the screw with a sequential distribution along its length of the zones of supply of the dry mixture, water, solution of additives and foam.

The disadvantages of the known installation (D4) are a narrow density range of foam concrete (light and ultra-lightweight foam concrete are not available), high heterogeneity and defectiveness of the pore structure, high thermal conductivity and low mechanical strength of the foam concrete.

The installation for the preparation of foam concrete mixture (D5) provides a continuous input of dry components, foam and mixing fluid into a horizontal cylindrical mixer of two parts of different diameters. The ratio of greater to less than 1.01-3 for PB density of 1200-200 kg / m ^3, respectively.

The disadvantages of the known installation (D5) are the narrow density range of foam concrete (light and ultra-lightweight foam concrete are not available), high heterogeneity and imperfection of the pore structure, high thermal conductivity and low mechanical strength of the foam concrete.

Closest to the claimed installation on the set of essential features is the installation (D4) (prototype).

Also known are devices for the preparation of foam concrete, close to those claimed in their technical essence and the achieved result, but only in terms of individual devices of the proposed installation: SU 300332 (class B28C 5/38, publ. 01.01.1971) (D6); RU 2077421 (CL B28C 5/38, publ. 04/20/1997) (D7); RU 2173257 (CL B28C 5/38, publ. 09/10/2001) (D8).

A device for the preparation of porous concrete (D6) includes mixing the components in the mixer, the gas and mixing chambers of which are made in the form of a single container separated by a porous partition, and the blades on the back have nozzles for aeration of the mixture in the rarefaction region created by their rotation.

The disadvantages of the known device (D6) are the cyclic (periodic) mode of operation, low equipment productivity, high labor costs, a narrow range of foam concrete density (light and ultra-light foam concrete are not available), high heterogeneity and defectiveness of the pore structure, high thermal conductivity and low mechanical strength of the product.

The mortar aeration device (D7) includes the simultaneous supply of the original mortar, foaming additive and compressed air to the continuous mixer. The foam-forming additive and compressed air are mixed in a separate chamber, forming a finely porous foam, which, passing an annular gap, mixes with the initial solution, providing quick and uniform mixing, i.e. its aeration with subsequent withdrawal of the aerated (porous) solution.

A disadvantage of the known device (D2) is the narrow density range of the foam concrete due to the relatively low degree of aeration, so the average density of the resulting foam concrete is 860 kg / m ³ . Device (D2) cannot be used to produce light 200-400 kg / m ³ and ultralight foam concrete with a density of less than 200 kg / m ³ .

The mixer for producing aerated concrete mixture (D8) is a batch apparatus combining the functions of a mixing device, a hydromechanical activator, a foam generator, an air chamber pump that delivers aerated concrete mixture through a mortar pipe to a distance proportional to the amount of overpressure.

The disadvantages of the known device (D8) are the cyclic (periodic) mode of operation, low equipment productivity, high labor costs and losses of aerated concrete mixture due to periodic cleaning of the mortar pipe from the “frozen” mixture, a narrow foam density interval (light and ultra-light foam concrete are not available), high heterogeneity and defective pore structure, high thermal conductivity and low mechanical strength of foam concrete.

The similarity of the devices (D6, D7, D8) with the proposed mixer-aerator of the foam mass as part of the inventive installation is the combination of the functions of the foam generator and the mixer, and the similarity, additional to (D7, D8), is the use of compressed air. Closest to the claimed device of the mixer-aerator on the set of essential features is the device (D7) (prototype).

The technical result, which the proposed installation is aimed at, is a high-performance continuous mode of foam concrete preparation, a significant increase in the physical and mechanical characteristics and consumer properties of foam concrete due to an increase in the uniformity and defect-free structure, a decrease in thermal conductivity and an increase in mechanical strength, a significant expansion of the foam concrete density range to the side lower border up to 70 kg / m ³ , reducing labor costs due to the high degree of mechanization and installation automation.

To achieve the specified technical result, there is proposed a facility for producing foam concrete (Fig. 1), including a mixer-activator of cementing components with aggregate and additives, a mixer-activator of a foaming agent, a mixer-aerator of foam mass, a foam-mass pipe-structure former, which is a channel for transporting foam mass into the formwork, a system automatic control of individual devices and the installation as a whole, as well as automatic dispensers of all components of the foam mass, storage tanks of activated dis A version, pumps, an air compressor, while a binder component dispenser, a filler dispenser, an accelerator, plasticizer and other additives dispenser, a water dispenser are connected to a binder component activator mixer with a filler and additives, which in turn is associated with an activated binders dispersion storage tank and then, through a binder pump, it is connected to a foam mass mixer-aerator, which, through the foam mass-structuring agent, enters the formwork, at the same time, a dispenser of the foam concentrate and doses water torus connected with mixer-blowing agent activator, which is linked in turn with the storage capacity of an activated dispersion-foaming agent and further foaming the pump is connected to the aerator-mixer penomassy, reinforcing agents dispenser coupled to the input and / or output channel penomassoprovoda-structurant. The foam aeration mixer-aerator is made in the form of a cylindrical body divided by a foam divider into two chambers, with a nozzle for introducing a continuous flow of activated dispersant of the foaming agent located in the upper chamber and a compressed air inlet above the foam divider mounted on the central axis of the mixer with rotation located in the lower chamber two screws with opposite angles of inclination of the blades mounted on the Central axis of the mixer with the possibility of rotation, located in in the middle of the lower chamber, a foam outlet pipe and, finally, with a pipe for injecting a continuous flow of activated dispersion of binders located in the lower part of the housing above the lower blade screw. The channel of the foam mass-structuring agent is made in the form of a diffuser with a continuous distribution function of its cross-sectional area along the length of the channel, in particular direct, power-law, parabolic, hyperbolic and any other. The channel of the foam-mass builder is made in the form of a step diffuser as a discrete analogue of a continuous diffuser, consisting of a combination of any number of sections with a constant cross-sectional area, but different in magnitude of this area, while the sections are connected by transition couplings according to the increase in cross-sectional area. The channel of the foam-mass builder is made of a spiral-shaped cochlear diffuser with a continuous distribution function of the cross-sectional area along the length of the spiral logarithmic, hyperbolic or Archimedean. The channel of the foam mass-structuring agent is made of reinforced rubber, metal, synthetic fabric, plastic, composites, or a combination of the above and other materials. A combination of any number of sections with a variable cross-sectional area at the inlet and outlet of each section separately is installed at the outlet of the channel of the foam-mass flow-builder, and each section can take the form of a diffuser, confuser or cylinder.

To implement the proposed continuous method for producing foam concrete in the proposed installation of continuous operation, four significant differences from the above installations (D4, D5), including the prototype (D4), are implemented:

1. In two activator mixers, mixing-activating a dispersion of binders with water, aggregate and additives and a foaming agent dispersion with water is carried out separately to obtain thixotropic metastable states of these dispersions at the preparation stage [1],

2. The foam mass mixer-aerator implements a continuous regime of aerated compressed air of continuous dosed input activated flows in metastable states: dispersion of binders with aggregate and additives and dispersant of foaming agent with intensive joint mixing.

3. The material and the structure of the channel of the foam mass-builder due to the combination of continuous transportation of foam into the formwork with the defect-free structure of the foam allows the preparation of foam concrete, including ultralight with a density of less than 200 kg / m ³ with a homogeneous, closed, finely porous cellular structure with reduced water-solid ( W / T) ratio and high efficiency of the use of a foaming agent in the process of structure formation with a change in the ratio of foam (the ratio of the volume of foam to the volume of foam body) from a low multiple of 2-5 at the entrance to the channel to a high multiple of 8-15 at the exit and in the formwork

4. The mechanization and automation system using mathematical models of individual devices and the installation as a whole allows one operator to maintain a stable mode of continuous foam production with a maximum density error of ± 5 kg / m ³ and, if necessary, change tasks in the automatic control system quickly without stopping production, in particular, the density of the foam in the range of 70-1200 kg / m ³ . The principle of operation of the proposed installation and its individual devices, as well as their design features are illustrated in FIG. 1-3.

Installation for the implementation of the proposed continuous method for producing foam concrete as a technological core of many different complete sets of equipment for the production of various products or monolithic foam concrete includes (Fig. 1): a binder components dispenser 1, a filler dispenser 2, a dispenser of accelerators, plasticizers and other additives 3, a water dispenser 4, a foaming agent dispenser 5, a reinforcing additives dispenser 6, a mixer-activator of a binder solution 7, a mixer-activator of a foaming agent 8, a binder storage tank 9, a pump 10, mixer-aerator of foam mass 11, foam mass-forming agent 12, receiving tank (formwork) 13, air compressor 14, pump of foaming agent 15, storage tank of foaming agent 16, automatic control system 17.

The technological process in the proposed installation (Fig. 1) can be divided into three stages:

1. The step of activating the initial dispersions:

a) The initial components of the dispersion of binders with aggregate and additives are supplied to the batch-activator 7 through dispensers 1-4 in the following sequence: water, binders (cement, gypsum, lime, ...), special additives (plasticizers, hardening accelerators, stabilizers, ...). As a result of short-term (1-3 min) intensive mixing of the activator of the mixer-activator, creating a cavitation effect (perforated disk), the two-phase liquid-solid dispersion is brought into a metastable thixotropic state, which is characterized by intensive gel formation of binders (calcium hydrosulfoaluminate and tricalcium hydrosilicate) and is determined by a sharp decrease in viscosity to 100-500 Pa · s. Next, the activated liquid-solid dispersion of binders is discharged into the bin storage tank 9, where the physicomechanical parameters and gel distribution of the binders are averaged by mixing the blade turbine at a low speed, which preserves the metastable thixotropic state of the dispersion until it is loaded into the mixer-aerator 11 by pump 10 .

b) The initial concentrate of the foaming agent through the dispenser 5 and water through the dispenser 4 are fed into the batch-activating mixer 8. As a result of short-term (0.5-2 min) intensive mixing by the working body of the activator-mixer, creating a cavitation effect (perforated disk), liquid - the liquid dispersion of the foaming agent is brought into a metastable thixotropic state, which is characterized by a sharp decrease in viscosity to 10-200 Pa · s and the total energy of hydrogen bonds in the range of 50-91 kJ / mol. Next, the activated dispersion of the foaming agent is discharged into the storage tank 16, where the gel composition and the physicomechanical parameters of the dispersion are averaged by mixing the blade turbine at a low speed, which preserves the metastable thixotropic state of the dispersion until it is loaded into the mixer-aerator 11 by pump 15.

The activation intensity of both dispersions (mixing time and speed of the working bodies) at the activation stage is set so that the foam mass in the formwork 13 retains a metastable state for at least 5-10 minutes. The criterion for the end of the metastability period is the approach to zero of the time derivative of the electrical resistance of the foam. This indicator, along with indicators of mixing power in the automatic control system, allows you to organize feedback to control the stage of activation of both dispersions.

2. The stage of aeration of the dispersion of binders.

The step of mixing and aerating the activated dispersions of binders and foaming agent is performed in the mixer-aerator of the foam mass 11 continuously under pressure. The multiplicity of the foam (the ratio of the volume of the foaming agent to the volume of the foam) under normal conditions is 8-15. With an increase in overpressure up to 2.5 MPa, the foam multiplicity decreases to 2-5. The maximum overpressure is theoretically unlimited, but practically does not exceed 2.5 MPa in order to avoid a sharp increase in the cost of manufacturing and operating equipment, in addition, this is the maximum allowable pressure of air compressors for general industrial and general construction purposes. The principle of operation of the foam aeration mixer-aerator and its design are illustrated by the diagram in Fig. 2. The cylindrical body of the mixer-aerator is divided by a foam divider into two chambers: an upper and a lower one, and has three receiving pipes for continuous inlet flows and one discharge pipe for foam. The activated dispersion of binders is supplied by the pump 10 through the inlet pipe in the lower chamber of the aerator mixer above the lower blade screw, the activated dispersion of the foaming agent is supplied by the pump 15 through the inlet pipe above the foam divider and the compressed air is supplied by the compressor 14 through the inlet pipe in the upper chamber. The finely porous, elastic foam formed in the upper chamber by means of a divider rotating at a speed of 1000-1500 1 / min enters the lower mixing chamber, in which it is intensively mixed with the oncoming flow of dispersion of binders. The counter motion of the mixed dispersions is carried out by two high-speed screws with opposite angles of inclination of the blades with a rotation speed of 1000-1500 1 / min, providing intensive and uniform mixing of the dispersion. The aerated solution (foam mass) is continuously discharged in the middle of the lower chamber through the outlet pipe into the foam mass-forming agent 12.

Under conditions close to normal (atmospheric pressure 760 mm Hg, air temperature 0 ° C), low-density foam with high air filling are a three-phase gas-liquid-solid dispersion with a high viscosity rigid, inactive structure with dense "packaging" air bubbles. Shear deformation during mixing of the foam mass under normal conditions destroys the thin inter-pore shells in the cellular structure of the foam mass with the formation of multiple defects of the cellular structure, which sharply reduce the physical and mechanical characteristics and consumer properties of the foam concrete.

During isothermal compression of a certain amount of foam mass, pressure increases and its volume decreases due to a decrease in the volume of the gas phase of the foam mass with a constant volume of liquid and solid phases (practically incompressible), i.e. the relative volume of the gas phase decreases according to the equation of state of the Mendeleev-Clapeyron gas [2]:

where: P is the gas pressure, V is the volume of gas, n is the number of moles of gas, R is the universal gas constant, T is the gas temperature.

When the pressure of the pumps and compressor increases, the mass velocity of the input flows increases, while the pressure increases in the mixer-aerator 11 (isochoric increase in pressure), the amount of foam mass also increases, and therefore, the volume of practically incompressible liquid and solid phases increases due to a decrease in the relative volume of gas phase (1). The bubbles of compressed air are reduced in volume, therefore, the inter-pore liquid-solid shells of the foam mass are thickened, which reduces its viscosity, i.e. increases the structural mobility and, consequently, the structural stability of the foam during the preparation and transportation of it to the formwork.

In addition, when mixing and transporting the foam mass, the number of defects in its cellular structure decreases, since with an increase in the thickness of inter-pore liquid-solid shells, the allowable value of shear deformations without destroying the pore structure increases. The increase in the structural stability and homogeneity of the foam mass is also explained by the increase in the elastic reaction of compressed air bubbles with increasing pressure and their tendency to spherical shape, i.e. the desire to occupy the maximum volume with a minimum surface.

There are many mathematical models for describing the rheology of various disperse systems. So, for example, to assess the viscosity of dispersions of spherical particles, Einstein proposed formula (2), often used to date [3]:

where η is the dispersion viscosity, η _cp is the viscosity of the dispersion medium, Φ is the volume concentration of the filler, K ₁ is a constant.

For solid spherical particles under the condition of a laminar flow of a dispersion medium, Einstein obtained a K ₁ value of 2.5. For foam mass, the dependence of the dispersion viscosity on filling with air should be sought in the form similar to (2) with the selection of the constant K ₁ according to the experimental results for a certain composition of the foam mass.

Thus, the stage of aerating the dispersions of binder and foaming agent is essentially the conversion of compressed air and two two-phase dispersions into one three-phase gas-liquid-solid dispersion called foam mass, which continuously enters the next stage: transportation and structuring.

The foam mass obtained in the mixer-aerator at elevated pressure as a three-phase gas-liquid-solid dispersion is in a metastable thixotropic state with high structural mobility (low viscosity), which is a necessary prerequisite for the targeted formation of defect-free, fine-porous, closed cell structure of ultra-lightweight foam concrete with high consumer properties.

3. The stage of transportation and defect-free structuring of the foam mass is carried out in the channel of the foam mass-builder 12 continuously with a smoothly controlled reduction of excess pressure from the maximum (no more than 2.5 MPa) in the mixer-aerator and almost to zero (no more than 0.05 MPa) at the output from the channel under restrictions of the linear velocity of the foam mass and its residence time in the channel.

The second stage of obtaining low-density foam concrete discussed above is described in article [4], where the method was given the name “compression-relaxation”. If the compression process in [4] is described in sufficient detail, then the relaxation process at the stage of transportation and structuring of the foam mass is not considered and is not described.

Below is a mathematical description of both the second and third stages of the technological process, which ensures the formation of an optimal defect-free finely porous closed-cell cellular structure of foam concrete of any density, including ultralight foam concrete with a density of less than 200 kg / m ³ , with high physical and mechanical (consumer) properties. A proposal is also made for choosing the material and design of the foam mass-structuring agent 12 as an integral element of the proposed installation for a continuous method for producing foam concrete (Fig. 1).

The proposed continuous method for producing foam concrete, taking into account the above description and in development [4], will be referred to hereinafter as “activation-aeration-structuring”.

The proposed design of the foam-mass-forming agent are shown in Fig. 3. The cross-section of the channel of the foam-mass-forming agent can be of any shape, including a circle, which provides the maximum cross-sectional area with the same perimeter for different figures.

In contrast to the existing foam mass pipelines with a constant channel cross-sectional area (option a in Fig. 3), three versions of the foam-mass-structuring channel with a variable cross-sectional area (Fig. 3) are proposed for defect-free structuring of the foam mass: b) a diffuser with an arbitrary area distribution function cross-section along the length, in particular straight, power-law, parabolic, hyperbolic, etc., c) a step diffuser as a discrete analogue of the above, d) a snail diffuser, i.e. diffuser in the form of a spiral, including logarithmic, hyperbolic or Archimedean. The snail diffuser is used for compact placement of the foam mass-structuring agent in mobile installations for construction conditions.

For all options, a combination of any number of sections with a variable cross-sectional area at the inlet and outlet of each section separately can be installed at the outlet of the channel of the foam-mass flow-builder along the course of the foam mass movement, while each section can take the form of a diffuser, confuser or cylinder, i.e. the section is controlled for fine-tuning the channel of the foam-mass flow-forming agent during operation and its rough adjustment in the process of starting when filling the channel (Fig. 3).

Separate independent change in the cross-sectional area at the inlet and outlet of each section can be performed in various ways. One possible way is to use plates that slide along the rails with the adjacent plates superimposed on each other, similar to a fan. The plates slide along the guide grooves on two belts mounted around the perimeter at the inlet and outlet of each section. To change the cross-sectional area at the inlet and / or outlet sections change the length of the corresponding belt and, therefore, its perimeter. Since the overpressure of the foam mass at the outlet of the channel is small, self-sealing of the fan-shaped plates reliably prevents lateral leakage of the foam. To increase the tightness, if necessary, an elastic and / or corrugated sleeve along the section is fixed on the belts on the inside of the section. A constructive analogue of a section with a variable cross-sectional area at the inlet and outlet is a controlled nozzle of a turbojet engine [5].

As a result of smooth, controlled relaxation of the bulk and shear stresses of the foam mass with a decrease in pressure during its movement in the channel of the foam mass-forming agent 12, the optimal porosity of the foam mass with minimal defect in the cellular structure is formed, which allows the preparation of ultralight foam concrete with a density of less than 200 kg / m ³ with a uniform, closed, finely porous cellular structure with reduced water-solid (W / T) ratio and high efficiency of using a foaming agent in the process of structural mations to change foam multiplicity of nizkokratnoy 2-5 in the mixer-aerator before vysokokratnoy 8-15 in the formwork.

The following are examples of the choice of material and design of the foam mass-structuring agent (Fig. 4, 5). In stationary sets of equipment for the preparation of foam concrete using options (a-c) in FIG. 3, as a rule, reinforced rubber, metal, woven with synthetic thread, plastic, composite, or combined from the above and other materials relatively long hoses are used. For mobile installations, relatively short compact foam lines, including spiral spiral diffusers-snails d) in FIG. 3 of composite materials or metal, with a high ratio of the cross-sectional area at the outlet and inlet of the channel and a relatively large heat transfer surface with low thermal resistance (see diagram b in Fig. 5).

The proposed foam mass-structure former 12 in addition to actually transporting the foam into the formwork 13 creates the necessary conditions for defect-free structure of the foam during its movement and relaxation of volume and shear stresses with a decrease in pressure in the channel. In this case, all air bubbles of all sizes gradually, simultaneously and evenly increase in volume according to (1), expanding the pore structure of the foam mass and preserving the gel composition of binders (calcium hydrosulfoaluminate and tricalcium hydrosilicate) and the thixotropic metastable state of liquid-solid inter-pore shells.

With the relaxation of the foam mass along its movement in the channel with an increase in the volume of the gas phase, the volume of the foam mass and, consequently, its space velocity at a constant mass velocity increase accordingly. With an increase in the space velocity, the linear flow velocity also sharply increases if the foam mass channel has a constant cross-sectional area, for example, cylindrical. At a very high linear velocity, the boundary turbulent flow layer near the channel wall expands and gradually covers the entire cross section of the flow with the destruction of the pore structure of the foam mass, the destruction of the gels of the binder components and the loss of the thixotropic metastable state of the foam mass. To prevent this phenomenon, it is necessary to limit the linear flow rate by increasing the cross-sectional area of the foam channel. An ideal design under this condition is a continuous diffuser (option b in FIG. 3). But this design is difficult to implement in practice, therefore, a simpler version of the step diffuser is also proposed (version c in Fig. 3).

The use of diffusers (Fig. 3) also solves the second important problem - the regulation of the residence time of the foam mass under conditions of its defect-free structure while continuing the process of hydration of binders and the formation of the crystalline structure of the future foam concrete from a three-phase gas-liquid-solid dispersion in a colloidal metastable state.

Thus, the necessary conditions for choosing the optimal design of the channel of the foam-mass flow-builder 12 are restrictions on the maximum linear velocity of the foam mass and the minimum time it remains in the channel of the foam-mass flow. For the following examples of designing the channel of the foam mass-structuring agent (Fig. 4, 5), the maximum linear velocity of the foam mass does not exceed 1 m / s. The minimum residence time of the foam in the channel is at least 60 seconds.

In FIG. Figures 4 and 5 show distribution diagrams of the following parameters along the length of the foam mass flow-forming agent: linear velocity of the foam mass and temperature

Designations in the diagrams: t is the total residence time of the foam mass [s], the ambient temperature is 288 K, the heat transfer coefficient is 133 [W / (m ² · deg)].

but). Variants of the foam mass-structure former 25 m long for stationary installations:

1. 5_5_25 - cylinder, diameters: initial 5 cm, final 5 cm,

2.5_10_25_K - diffuser, diameters: initial 5 cm, final 10 cm,

3. 5_10_25_C - step diffuser, diameters: initial 5 cm, final 10 cm,

4. 5_20_25_K - diffuser, diameters: initial 5 cm, final 20 cm,

5. 5_20_25_C - step diffuser, diameters: initial 5 cm, final 20 cm.

b) Variants of the foam mass-structuring agent 5 m long for mobile installations:

1. 5_5_5 - cylinder, diameters: initial 5 cm, final 5 cm,

2.5_50_5_U - snail, diameters: initial 5 cm, final 50 cm.

Note in FIG. 4, 5 the optimal choice of the parameters of the cone-shaped diffuser (option b in Fig. 3) and the step diffuser (option c in Fig. 3) while maintaining the limitation on the maximum linear velocity of the foam mass. We also note a significant increase in the residence time of the foam in the foam channel with an increase in the outlet diameter of the channel. This is especially important for mobile installations with a relatively short compact foam mass pipe, for example, in the form of a diffuser-cochlea (variant d in Fig. 3).

Projects of the channels of the foam mass-structuring agent 12 shown in FIG. 4, 5 as examples, were developed using the mathematical model of the foam mass-structuring agent 12 as a process of free movement of foam mass (three-phase gas-liquid-solid dispersion) in a channel of variable cross-section, taking into account friction of foam mass on the channel walls and heat transfer with the environment, as well as mathematical models of a mixer-aerator of foam mass 11 as a process of intensive mixing of three continuous input streams [6, 7]. These models of the two main stages of the proposed continuous method for producing foam concrete are the core of the general mathematical model.

The mathematical description. The basis of the system of equations for the mathematical description of the processes in the proposed installation for producing foam concrete by the proposed method “activation-aeration-structuring” is constituted by the equations of material and heat balances for continuous input feed streams and output foam flow as a three-phase gas-liquid-solid dispersion. Into the components and general material balance equations include the intensities of all sources of matter (solid, liquid and gas components). The heat balance equations include the intensities of all heat sources in the flows [6].

The following is a system of equations for the mathematical description of the two main stages in the production of foam concrete: compression, mixing and aeration in the mixer-aerator 11 and the transportation and structuring of foam in the foam mass-forming unit 12.

MIXER-AERATOR. Due to the intensive mixing of the input flows in the working area of the mixer-aerator, the distribution of parameters over the volume can be neglected and a simplified hydrodynamic model in the working area can be adopted - ideal mixing [6].

The system of equations for the conservation of the components of the foam mass during their mixing in the mixer-aerator (component-wise material balance) in this case has the form:

, $${\text{v}}_{\text{p}}{}^{\left(\text{0}\right)}$$

, $${\text{v}}_{\text{v}}{}^{\left(\text{0}\right)}$$

- массовые скорости входных потоков вяжущих, пенообразователя и воздуха соответственно [кг/с], v - массовая скорость выходного потока пеномассы [кг/с], n - количество компонент в твердой, жидкой и газовой фазах потоков; $$X_{ci}{}^{\left(0\right)}$$

, $$X_{pi}{}^{\left(0\right)}$$

_, $$X_{pi}{}^{\left(0\right)}$$

- массовая доля i-го компонента во входных потоках вяжущих, пенообразователя и воздуха соответственно, X_i - массовая доля i-го компонента в выходном потоке, $$G_i{}^{{\displaystyle \sum }}$$

- суммарная интенсивность источников i-го компонента в смесителе-аэраторе [кг/с].Where: $${\text{v}}_{\text{c}}{}^{\left(\text{0}\right)}$$

, $${\text{v}}_{\text{p}}{}^{\left(\text{0}\right)}$$

, $${\text{v}}_{\text{v}}{}^{\left(\text{0}\right)}$$

are the mass velocities of the input flows of binders, foaming agent and air, respectively [kg / s], v is the mass velocity of the output flow of the foam mass [kg / s], n is the number of components in the solid, liquid, and gas phases of the flows; $$X_{ci}{}^{\left(0\right)}$$

, $$X_{pi}{}^{\left(0\right)}$$

_, $$X_{pi}{}^{\left(0\right)}$$

- mass fraction of the i-th component in the input flows of binders, foaming agent and air, respectively, X _i - mass fraction of the i-component in the output stream, $$G_i{}^{{\displaystyle \sum }}$$

- the total intensity of the sources of the i-th component in the mixer-aerator [kg / s].

The equation for the conservation of the substance of the foam mass (total material balance) has the form:

The equation for the conservation of energy of the foam mass (heat balance) in the mixer-aerator has the form:

, $${\text{C}}_{\text{p}}{}^{\left(\text{0}\right)}$$

, $${\text{C}}_{\text{v}}{}^{\left(\text{0}\right)}$$

- теплоемкости входных потоков вяжущих, пенообразователя и воздуха соответственно [Дж/кг/град], $${\text{T}}_{\text{c}}{}^{\left(\text{0}\right)}$$

, $${\text{T}}_{\text{p}}{}^{\left(\text{0}\right)}$$

, $${\text{T}}_{\text{v}}{}^{\left(\text{0}\right)}$$

- температура входных потоков вяжущих, пенообразователя и воздуха соответственно [K]. C - теплоемкость выходного потока, Т- температура выходного потока, Q^Σ - суммарная интенсивность источников тепла.Where: $${\text{C}}_{\text{c}}{}^{\left(\text{0}\right)}$$

, $${\text{C}}_{\text{p}}{}^{\left(\text{0}\right)}$$

, $${\text{C}}_{\text{v}}{}^{\left(\text{0}\right)}$$

- the heat capacity of the input flows of binders, foaming agent and air, respectively [J / kg / deg], $${\text{T}}_{\text{c}}{}^{\left(\text{0}\right)}$$

, $${\text{T}}_{\text{p}}{}^{\left(\text{0}\right)}$$

, $${\text{T}}_{\text{v}}{}^{\left(\text{0}\right)}$$

- the temperature of the input flows of binders, foaming agent and air, respectively [K]. C is the heat capacity of the output stream, T is the temperature of the output stream, Q ^Σ is the total intensity of the heat sources.

FOAM-MASS PIPE-STRUCTURE-FORMER 12. The structure of the foam flow in the channel can be approximately represented by a simplified hydrodynamic model - ideal displacement in the sense that each subsequent layer of foam in the cross section of the channel displaces the previous one. Moreover, a change in all flow parameters in the layer can be neglected, i.e. each layer is perfectly mixed and therefore homogeneous. Change of parameters takes place only along the length of the channel [6]. The adopted hydrodynamic model quite satisfactorily describes the real hydrodynamic situation in the channel due to the peculiarity of the movement of the three-phase dispersion in the thixotropic state, the rheology of which is characterized by a sharp decrease in the flow viscosity at the channel wall when the tensile strength and cohesive rupture of the dispersion near the channel wall are exceeded [7]. The diagram of linear flow velocities in the channel, which is characteristic of a three-phase gas-liquid-solid dispersion in the thixotropic state, is shown in FIG. 6: 1 is the region of cohesive flow discontinuity near the channel wall, 2 is the region of the pivotal flow movement in which there are no shear deformations, and, therefore, this is a stable region of foam mass structuring, which preserves this most important condition throughout the foam mass pipeline [7].

The system of equations for the conservation of the components of the foam mass in an arbitrary section of the channel during the movement and structuring of the foam mass in the channel (component-wise material balance):

- суммарная интенсивность источников i-го компонента в твердой, жидкой и газовой фазах в произвольном сечении канала [кг/с].Where: $$C_i^{{\displaystyle \sum }}\left(l\right)$$

- the total intensity of the sources of the i-th component in the solid, liquid and gas phases in an arbitrary channel section [kg / s].

The equation for the conservation of the substance of the foam mass (total material balance) in the channel has the form:

The equation of conservation of energy (heat balance) of the foam mass in an arbitrary section of the channel has the form:

where: v is the mass velocity of the foam mass in the channel [kg / s]; C is the specific heat of the foam mass in the channel [J / kg / deg]; T (l) is the temperature of the foam mass in an arbitrary section of the channel [K]; Q ^Σ (l) is the total intensity of heat sources in an arbitrary section of the channel [j / s].

INTENSITY SOURCES. The intensities of the sources of substances (components) and heat characterize the rates of influx (formation) or runoff (consumption) of substances and heat in the stream due to the following basic elementary processes [6]: chemical reactions (R), mass transfer (M), change in the state of aggregation, or phase transitions (A), recharge by external flows (P), heat transfer (T), heat radiation (I).

The total intensities of the sources of substances and heat are determined by the sums of intensities of elementary processes according to the above classification:

In the process of compression, mixing and aeration of the foam mass in the mixer-aerator 11, as well as its movement and structuring in the channel 12, almost all of the above elementary processes theoretically take place.

So, for example, for the heat transfer process, the intensity of the heat source (Q ^T ) are expressed in terms of the surface area of the considered heat transfer zone (F ^T ):

For a mixer-aerator, 11 F ^T is its surface area. For channel 12, F ^T is its perimeter, generally variable along the length of the channel.

The local intensity of the heat source in the process of heat transfer to the environment (q ^T ) is determined by the following expression:

where: K ^T - heat transfer coefficient; T _c is the temperature of the environment; T is the local temperature of the foam flow. For the mixer-aerator 11 is the temperature of the foam in the apparatus. For channel 12, this is the local temperature of the foam flow variable along the length of the channel.

In practice, in mathematical modeling of processes in the mixer-aerator 11 and channel 12, the following elementary processes can be neglected due to their relative smallness or absence: chemical transformations, mass transfer, phase transitions, external recharge, and heat radiation.

In particular, the following important remark was taken into account [8]: the intensities of the sources of substances in the processes of chemical transformations in the mixer-aerator 11 and in the channel 12 are so small that they can be neglected. This is due to the peculiarities of the hydration process of the main cement constituents: tricalcium C ₃ S and dicalcium C ₂ S silicates, tricalcium aluminate C ₃ Al. At the first stage of the hydration process, as soon as C ₃ S comes into contact with water, a high reaction rate and heat release are observed, respectively, and then its sharp decline [8]. Called the pre-induction period, this stage lasts several minutes and ends during the first preparatory stage of activation of the initial liquid-solid dispersion of binders in apparatuses 7 and 9 (Fig. 1). At the second stage of the hydration process, the rate of chemical transformations is very low [8]. This is the induction period, which lasts several hours and ends in the formwork 13. Therefore, when studying and modeling the two main stages of the proposed method for the continuous production of foam concrete in the apparatus 11 and 12 (Fig. 1), chemical transformations during hydration can be neglected. In addition, the increase in the duration of the induction period and the decrease in the rate of the chemical reaction of hydration is due to the peculiarity of the structure of the foam mass, in contrast to heavy ordinary concrete, and is explained by the slowdown of the process of water transfer in relatively thin inter-pore shells.

The analysis of completed projects for the implementation of the stage of transportation and structuring of foam in the foam mass-forming agent 12 (Fig. 4, 5) shows the high sensitivity and reliability of the developed mathematical models of the mixer-aerator of foam mass and foam-mass-forming agent, which are part of the general mathematical model of the proposed continuous method for producing foam concrete " activation-aeration-structuring. "

Test examples of the proposed method for producing foam concrete and installation for its implementation are presented in the table in FIG. 7. Table 1 “Physico-mechanical properties of foam concrete depending on the preparation mode” shows the results of experiments to study the physical and mechanical properties of foam concrete, in particular thermal conductivity and compressive strength, depending on the technological parameters of activator mixers and aerator mixer for various grades foam concrete 100, 200, 400. Test results show a significant increase in consumer properties of foam concrete. In comparison with existing brands of foam concrete of appropriate density, the present invention by reducing the number of structural defects allows to reduce the thermal conductivity of foam concrete by 1.5-2 times and increase its mechanical strength by 3-5 times.

The average productivity of the installation used in the experiment and implementing the proposed method for producing foam concrete, for example, grade 100 is 60 m ³ / hour. To mark 400 capacity is 15 m ³ / hour. For many existing plants with a periodic method of producing foam concrete, including the prototype, the average productivity does not exceed 5 m ³ / hour. The productivity of the proposed installation for the preparation of foam in comparison with the existing ones increases by 3-10 times depending on the density of the foam concrete.

The mechanization and automation system using the proposed mathematical models of individual devices and the installation as a whole allows one operator to maintain a stable mode of continuous foam concrete preparation with a maximum density error of ± 10 kg / m ³ and, if necessary, change tasks in the automatic control system quickly without stopping production, particular foam density in the range of 70-1200 kg / m ³ .

Information sources

1. Levin L.I., Yudovich B.E., Zubehin S.A., Didenko V.A., Zlobin V.V., Konovalov A.G.

A method of manufacturing foam concrete and foam concrete obtained by this method / RF patent for the invention No. 2239615, application No. 2001117620, priority June 28, 2001, registration on November 10, 2004.

2. Stromberg A.G., Semchenko D.P. Physical chemistry: Textbook. for chem. specialist. Universities / Ed. A. G. Stromberg. - 7th ed. - M .: Higher. school, 2009 .-- 527 p. - ISBN 978-5-06-006161-1.

3. Einstein A. Über die von der molekularkinetischen Theorie der Wärme geforderte Bewegung von in ruhenden Flüssigkeiten suspendierten Teilchen. // Annalen der Physik. - 1905.- 322 (8). - P. 549-560.

4. Kobidze T.E., Korovyakov V.F., Samborsky S.A. Obtaining low-density foam concrete for the manufacture of products and monolithic concreting // Builds. materials. 2004. No. 10. S. 56-58.

5. Gusenko S. M., Demchenko A. V., Pyrkov S. N., Marchukov E.Yu. Jet nozzle with a controlled thrust vector for a turbojet engine / RF Patent for invention No. 2455513, Application No. 2010149289, priority 02.12.2010, registration 10.07.2012

6. Boyarinov A.I., Kafarov V.V. Optimization methods in chemical technology. M .: Chemistry, 1975, 576 p.

7. Loginov V.Ya. Single screw molding of three-phase dispersed compositions. Modeling and optimization. // ISBN: 978-3-659-16575-7. LAP LAMBERT Academic Publishing. Saarbrücken, Deutschland. 2012.191 c.

8. Yudovich B.E., Zubekhin S.A., Didenko V.A. A method of manufacturing cement, concrete based on it and concrete and reinforced concrete products and monolithic structures from the obtained concrete / ЕАСО patent No. 002673, application No. 200000454, priority 03/23/2000, registration 08/29/2002

Claims (7)

1. The method of producing foam concrete, including the preparation of the process mixture by mixing the concentrate of foaming agent, water, binders, aggregate, additives and aeration of the mixture with compressed air in the mixer, characterized in that the method of producing foam concrete is carried out continuously in three stages, while the first stage is mixing -activation of binders with water, aggregate and additives in the mixer-activator with a speed of 1500-3000 1 / min rotation of the working body with a cavitation effect to obtain a liquid-solid dispersion binders in a thixotropic metastable state with a decrease in viscosity to 50-500 Pa · s, in another mixer-activator, the foaming agent concentrate is mixed-activated with the addition of water to obtain a liquid-liquid dispersion of the foaming agent in a thixotropic metastable state with a decrease in viscosity to 10-200 Pa · s, at the second stage in the mixer-aerator with a speed of rotation of the working bodies of 1000-1500 1 / min are mixing continuous flows of both previously activated dispersions with their simultaneous aeration with compressed air, etc. and an excess pressure of 0.25-2.5 MPa, and in the third stage, the foam mass obtained in the mixer-aerator continuously enters the channel of the foam mass-forming agent in the form of a diffuser, combining the continuous transportation of the foam mass into the formwork and its defect-free structuring in the free movement mode under the action of the difference pressures of 0.25-2.5 MPa at the entrance to the channel and 0.01-0.1 MPa at its exit while limiting the maximum linear flow rate and the minimum residence time of the foam mass in the channel. 2. Installation for producing foam concrete according to claim 1, including a mixer-activator of cementitious components with aggregate and additives, a mixer-activator of a foaming agent, a mixer-aerator of foam mass at excessive pressure, a foam mass-structure-forming agent, which is a cylindrical channel for transporting foam mass into the formwork, an automatic system control of individual devices and the installation as a whole, as well as automatic dispensers of all components of the foam mass, storage tanks of activated dispersions, pumps, air a compressor, with a binder component dispenser, a filler dispenser, an accelerator, plasticizer and other additives dispenser, a water dispenser connected to a binder component activator mixer with a filler and additives, which in turn is connected to a storage tank of activated binder dispersion and then through a binder pump connected to a foam-mixer-aerator, which enters the formwork through the foam-mass-pipe-forming agent, at the same time the foam concentrate dispenser and the water dispenser are connected to cm a foaming agent activator, which in turn is connected to a storage tank of the activated dispersant of the foaming agent and then connected to a foam mass mixer-aerator through a foaming pump, a dispenser of reinforcing additives is connected to the input and / or output of the channel of the foam mass-structuring agent. 3. Installation for producing foam concrete according to claim 2, characterized in that the foam aeration mixer-aerator is made in the form of a cylindrical body, divided by a foam divider into two chambers, with an inlet of a continuous stream of activated dispersion of the foaming agent located in the upper chamber and a nozzle of inlet of compressed air above a foam divider mounted on the central axis of the mixer with the possibility of rotation, as well as with two screws located in the lower chamber with opposite angles of inclination of the blades, set at a price the swivel axis of the mixer with the possibility of rotation, with a foam outlet pipe located in the middle of the lower chamber and, finally, with a pipe for introducing a continuous flow of activated binder dispersion located in the lower part of the housing above the lower blade screw. 4. Installation for producing foam concrete according to claim 2, characterized in that the foam mass-forming agent is made of reinforced rubber, metal, synthetic fabric, plastic, composites or a combination of the above materials and is made in the form of a diffuser with a continuous distribution function of the channel cross-sectional area along it length, in particular straight, power, parabolic, hyperbolic and any other. 5. Installation for producing foam concrete according to claim 2, characterized in that the foam mass-forming agent is made in the form of a step diffuser as a discrete analogue of a continuous diffuser, consisting of a combination of any number of sections with a constant cross-sectional area, but different in magnitude of this area, sections are connected by the growth of the cross-sectional area with transitional couplings. 6. Installation for producing foam concrete according to claim 2, characterized in that the foam mass-structuring agent is made in the form of a spiral-shaped diffuser-cochlea with a continuous distribution function of the cross-sectional area along the length of the spiral logarithmic, hyperbolic or archimedean. 7. Installation for producing foam concrete according to claim 2, characterized in that the foam mass-flow former at the outlet includes a combination of any number of sections with a variable cross-sectional area at the inlet and outlet of each section separately, each section can take the form of a diffuser, confuser or cylinder .

Images