RU2816607C1 - Method for volumetric hydrophobization of construction products at production stage - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to the industry of construction materials and can be used in the manufacture of construction products with hydrophobic properties for use inside residential and public buildings and facade works. Method for volumetric hydrophobization of construction products at the stage of production with automatic control mode of a moulding machine involves adding a hydrophobisator – an organosilicon polymer into the mixing water before dosing the mineral gypsum binder by combined dosing of water and a water repellent agent in a water dosing tank and mixing until a homogeneous mass is obtained. Further, the obtained mass is fed into a mixing unit for mixing with dosed mineral gypsum binder and obtaining a moulding solution of construction articles. Dispersing device with pump and high-pressure nozzles is used for supply of water repellent agent. Water repellent agent is fed into the water dosing tank by a high-pressure pump via a high-pressure pipeline by means of high-pressure nozzles located on a suspension frame in the lower part of the water dosing tank. High-pressure pump is equipped with a control unit, the input of which is connected to the main control panel of the moulding machine, and the output is to the electric drive of the high-pressure pump through the pump operation time relay.

EFFECT: increased homogeneity of gypsum solution due to uniform distribution of water repellent in mass of gypsum solution, reduced water absorption and improved quality of hydrophobic construction products, reduced number of defects on their surface.

1 cl, 2 dwg, 5 tbl

Description

Field of technology to which the invention relates

The invention relates to the building materials industry and can be used in the manufacture of building products with hydrophobic properties for use inside residential and public buildings and facade work.

For hydrophobization, organosilicon compounds are used, which are diluted with water or organic matter. They have a number of properties that not only prevent moisture from penetrating into the structure of the building material, but also protect the wall surface from the adhesion of dust and the appearance of efflorescence on the walls.

State of the art

There is a known method of volumetric hydrophobization, in which pre-made emulsions with a stabilizing agent are used to ensure uniform distribution of the water repellent in the volume of water. Typically, hydrophobizing emulsions are 50% aqueous emulsions of hydridesiloxanes, for example, GKE-50-94M or KE-30-04. The emulsion is introduced together with the mixing water or after, into the finished composition, subject to mixing with a mixer for at least 20 minutes.

The disadvantage of this method is the high consumption of the emulsion relative to other additives, the limited shelf life of the emulsion (from 70 days to 6 months) and poor results in reducing water absorption in gypsum products.

There is a known method of volumetric hydrophobization, which includes preliminary preparation of a hydrophobizing complex modifying additive, mixing it until a homogeneous mass is obtained with mixing water with intensive mixing and gypsum binder in a mixing unit, followed by molding the product. /Pat. 2375386 Russian Federation A method for producing a waterproof composite product (variants) and a composite product obtained by this method; Patent holder: Limited Liability Company "Preobrazhenie". – publ. 12/10/2009, Bulletin. No. 34/.

The disadvantage of this method is the uneven distribution of the filling volume; the formation of defects in places of increased polymer concentration on the surface of the boards after drying.

There is a known method of volumetric hydrophobization in the manufacture of gypsum boards in automatic mode, which involves adding organosilicon polymers to the mixing water before dosing the mineral binder. In this method, dosing of the water repellent is carried out together with dosing of water in a weighing water dispenser tank, where water and water repellent are mixed until a homogeneous mixture is obtained. Next, the resulting mixture of water and water repellent is poured into a mixing unit, where the required amount of gypsum is dosed, then all components are mixed for a certain time, and the resulting solution is poured into molds to produce building products. As an organosilicon polymer, substances from a number of hydride-containing siloxanes are used, which are the most universal, for example, such domestic products as GKZh-94, imported ones - SILRES BS-94, Xiameter MHX-1107. The advantages of this method include low consumption of additives to ensure the hydrophobic properties of the material, relative to other additives. /TU 5742-010-21151476-2013 GYPSUM PLATES, tongue-and-groove slabs for walls and partitions “EUROSIZE”/. Accepted as a prototype.

The disadvantage of this method is the low solubility of additives in water (rainbow stains are visible on the surface of the water); uneven distribution over the filling volume; the formation of defects - cavities (probably caused by the formation of a gaseous by-product) in places of increased polymer concentration on the surface of the slabs after drying.

Disclosure of the invention

The essence of the invention is to obtain a stable hydrophobic emulsion during the production of building products, to increase the homogeneity of the gypsum solution due to the uniform distribution of the water repellent in the mass of the gypsum solution, and as a result, to improve the quality of hydrophobic building products, to increase the efficiency of protecting building products from moisture absorption at a constant consumption rate water repellent. To achieve this goal, in the claimed invention, a dispersing device with high-pressure nozzles is used to introduce the additive.

The technical result of the invention is to increase the homogeneity of the gypsum solution due to the uniform distribution of the water repellent in the mass of the gypsum solution, reduce water absorption and improve the quality of hydrophobic building products, and reduce the number of defects on the surface of gypsum products.

The technical result is achieved by the fact that in the known method of volumetric hydrophobization of building products at the production stage with an automatic control mode of the molding machine, including the addition of an organosilicon polymer into the mixing water before dosing the mineral binder by jointly dosing water and water repellent in a weighing water dosing tank and stirring until homogeneous mass, followed by feeding it into the mixing unit for mixing with dosed mineral binder and obtaining a molding solution for building products, the peculiarity is that to supply the water repellent, a dispersing device with a pump and high pressure nozzles is used, and the water repellent is supplied to the water weighing tank a high-pressure pump through a high-pressure pipeline using high-pressure nozzles located on a suspension frame in the lower part of the water dosing tank, while the high-pressure pump is equipped with a control unit, the input of which is connected to the main control panel of the molding machine, and the output is connected to an electric drive high pressure pump through a pump operating time relay. Previously, before being supplied to the high-pressure pump, the water repellent is passed through a coarse filter.

When a water repellent is sprayed under high pressure into a liquid medium (water), it is dispersed - divided into small particles, microdroplets. Next, emulsification occurs (mixing two immiscible liquids) and homogenization of the active substance and mixing water.

The dispersing device includes a high-pressure pump, a high-pressure pipeline and high-pressure nozzles located at the bottom of the water weighing tank. High-pressure nozzles are installed statically on a suspension frame and secured using plumbing clamps and fittings.

Brief description of drawings

Figure 1 shows a diagram of a device for volumetric hydrophobization of building products at the production stage, which shows: a weight water dosing tank - 1, a low-pressure mixing water supply pipeline - 2, a low-pressure waterproofing agent supply pipeline - 3, a coarse filter - 4, a pump high pressure – 5, high pressure pipeline – 6, suspension frame with high pressure nozzles – 7, channel – 8, emulsion supply pipeline – 9, pipe-shaped screw dispenser of gypsum binder – 10, mixing unit – 11.

Figure 2 shows a block diagram of the automatic control system for the dispersing device, which shows: the main control panel of the molding machine - 12, the high-pressure pump control unit - 13, the pump operating time relay - 14 (timer), the electric drive of the high-pressure pump - 15.

The installation for implementing the proposed method of volumetric hydrophobization of building products is equipped with a dispersing device, which includes a high-pressure pump - 5, a high-pressure pipeline - 6, and high-pressure nozzles located on a suspension frame in the lower internal part of the water weighing tank - 1 The suspension frame with high-pressure nozzles 7 is mounted on a channel 8 located outside the weight water metering tank 1. The channel 8 is installed on the capital base of the weight water metering tank 1 and has no contact with the weight water metering tank 1, which eliminates error in the operation of weight sensors. High-pressure nozzles are located inside at the bottom of the water weighing tank 1. The water weighing tank 1 is connected to the mixing unit 11 by an emulsion supply pipeline 9.

Carrying out the invention

Mixing water enters the weighing water dispenser tank 1 through a low-pressure mixing water supply pipeline 2 connected to the bottom of the weighing water dispenser tank 1. The low-pressure water-repellent supply pipeline 3 is equipped with a coarse filter 4 and is connected to a high-pressure pump 5. The water-repellent agent is then cleaning with a coarse filter 4, a high-pressure pump 5 through a high-pressure pipeline 6 is supplied to the water weighing tank 1 and sprayed with high-pressure nozzles in the form of an aerosol mist. As a result of supplying the water repellent under pressure, in the form of an aerosol mist, and mixing with the mixing water entering the water weighing tank 1 through the low pressure mixing water supply pipeline 2, a direct emulsion of the water repellent in water is formed. The resulting emulsion is fed through the emulsion supply pipeline 9 to the mixing unit 11, where the gypsum binder coming from a pipe-shaped screw dispenser of gypsum binder 10 is mixed in it. The resulting molding solution of building products from the mixing unit 11 is fed into molds for pouring (not shown in the drawing) .

The automatic control system for the dispersing device includes the main control panel of the molding machine 12, connected to the input of the control unit of the high-pressure pump 13, which is connected to the electric drive of the high-pressure pump 15 through the pump operating time relay 14.

In the process of cyclic molding of gypsum boards, when the tap of the weighing water dosing tank 1 is opened to supply water with technological additives to the mixing unit 11, a signal is sent from the main control panel of the molding machine 12 to the control unit of the high-pressure pump 13. This control signal starts the time relay operation of pump 14 and the high-pressure pump 5 is turned on. By means of high-pressure nozzles in the water weighing tank 1, the process of dispersing the set amount of water repellent into the mixing water occurs. After working for the specified time, the high-pressure pump 5 is turned off, the resulting emulsion is drained from the water weighing tank 1 into the mixing unit 11. The tap of the water weighing tank 1 is closed, and a new dose of water is drawn.

During the next cycle of forming gypsum boards, the process of operation of the dispersing device is repeated.

In the production of hydrophobized gypsum boards, the dosing of the water repellent is carried out together with the dosing of water from the weighing dispenser into the mixing unit. Finished products are used as a water repellent, for example, domestic - GKZh-94 or imported - SILRES BS-94, Xiameter MHX-1107.

In the proposed invention, to obtain a temporary emulsion, the water repellent is supplied to the water weighing tank 1 using a dispersing device - high pressure nozzles, through which very small droplets (in the form of fog) of the water repellent are formed in the volume of mixing water. To do this, high-pressure nozzles with a suspension frame are installed in the lower part of the water weighing tank 1 using plumbing clamps and fittings, for example: IS-FOG-AD-SS (fog nozzles). The suspension frame with high-pressure nozzles 7 is fixed on a channel 8 attached to the capital base of the water weighing tank 1, which eliminates errors in the operation of the weight sensors.

The water repellent is supplied to the water weighing tank 1 by a high pressure pump 5 (more than 10 bar) through a high pressure pipeline 6 connected to high pressure nozzles. The water repellent, entering the weighing water dispenser tank 1 under high pressure, passes through the nozzles of the high pressure nozzles and is dispersed into very small drops in the water, forming a direct emulsion of the water repellent in the water of the dispenser tank. The duration of the process is from 25 to 60 seconds, depending on the set dose. The selected dose is regulated by the high-pressure pump timer 5.

The resulting emulsion retains its viability for several minutes, after which stratification occurs and the water repellent forms accumulations on the surface of the water, passing into a state identical to the classical method of introducing the additive.

However, the lifetime of the resulting emulsion is sufficient for subsequent technological processes of feeding it into the mixing unit 11 and mixing the gypsum binder in it.

To prevent clogging of the nozzles of the dispersing device, before supplying it to the high-pressure pump 5, the water repellent is passed through a coarse mesh filter 4 with a mesh size of no more than 5 microns.

Since the density of the water repellent is lower than the density of water, for better homogenization, the high-pressure nozzles of the dispersing device are located at the bottom of the water weighing tank 1.

Additional control over the operation of the high-pressure pump 5 and the high-pressure nozzles of the dispersing device is carried out using a pressure gauge (not shown in the figure), which reflects the pressure values in the section of the high-pressure line.

The authors of the invention conducted a series of tests, the results of which are presented below.

Test results with the same dosage of water repellent:

Protocol No. 1.

Testing the dosage method using a dispersing device from 01/17/2023 and 01/20/2023, comparison with method No. 1 - the usual method of supplying a water repellent, a previously known method, with the same dosage of the water repellent. The test results are shown in Table 1.

Table 1

Results 01/17/23 and 01/20/23 –
Water absorption of GGP "Eurosize" 667*500*80 mm according to GOST 6428-2018 (normative value - no more than 5%) Water repellent supply method Water absorption of samples from 1 pour (30 pcs.), by serial number of the slab in the cassette, from left to right, in% Average value
water absorption, in% Standard deviation of water absorption, in PP* Sample No. 5 Sample
No. 15 Sample
No. 25 01/17/2023 using a dispersing device
1st fill 1.71 1.80 1.47 1.66 0.17 using a dispersing device
2nd fill 2.52 2.98 1.87 2.46 0.56 using a dispersing device
3rd fill 2.15 3.59 2.79 2.85 0.72 Method No. 1
(regular feed)
1st fill 3.04 1.26 4.30 2.87 1.53 Method No. 1
(regular feed)
2nd fill 1.25 1.87 2.98 2.03 0.88 Method No. 1
(regular feed)
3rd fill 2.71 1.19 3.00 2.30 0.97 01/20/2023 using a dispersing device
1st fill 4.41 3.83 4.22 4.15 0.29 Method No. 1
(regular feed)
1st fill 3.44 5.15 4.95 4.51 0.93

*– in percentage points.

Conclusions based on the data obtained:

1. The use of a new dosage method using a dispersing device leads to a slight decrease in water absorption, on average;

2. The use of a new method of dosing the water repellent significantly improves its distribution throughout the entire volume of the fill.

The final data are shown in analytical table 2.

table 2

Water repellent supply method Overall average water absorption,
V % Total standard deviation of water absorption,
in PP Method No. 1
(regular feed) 2.9275 1.0775 using a dispersing device 2.78 (down by 0.1475) 0.435
(less by 0.6425
or 2.47 times)

Protocol No. 2.

Testing the dosage method using a dispersing device from 03/13/23.

Comparison with method No. 1 - the usual method of supplying water repellent, with the same dosage of water repellent. The test results are shown in Table 3.

Table 3

Results 03/13/23 –
Water absorption of GGP "Eurosize" 667*500*80 mm according to GOST 6428-2018 (normative value - no more than 5%) Hydrophobizer supply method Samples from 1 pour (30 pcs.), by serial number of the slab in the cassette, from left to right, in % Average value
water absorption, in% Standard deviation of water absorption, in PP Sample No. 1 Sample No. 5 Sample No. 15 Sample No. 25 Sample No. 30 using a dispersing device 1st fill 2.47 3.28 3.24 2.76 3.39 3.03 0.39 using a dispersing device 2nd filling 2.55 2.59 3.46 3.26 2.62 2.89 0.43 using a dispersing device 3rd filling 4.35 3.08 3.81 3.98 3.74 3.79 0.46 Method No. 1
(regular feed)
1st fill 5.40 4.53 3.16 3.78 4.25 4.23 0.84 Method No. 1
(regular feed)
2nd fill 5.27 5.25 4.10 3.57 3.27 4.29 0.93 Method No. 1
(regular feed)
3rd fill 4.10 5.13 4.96 3.61 5.60 4.68 0.81

Conclusions based on the data obtained:

1. The use of a new dosage method using a dispersing device leads to a slight decrease in water absorption, on average;

2. The use of a new method of dosing the water repellent significantly improves its distribution throughout the entire volume of the fill, taking into account a larger number of samples from the fill.

The final data are shown in analytical table 4.

Table 4

Water repellent supply method Overall average water absorption value, % Total standard deviation of water absorption, in PP Method No. 1
(regular feed) 4.4 0.86 using a dispersing device 3.2366
(down by 1.1634) 0.4266
(less by 0.4334 or 2.016 times)

Summary analytical data from all tests are given in Table 5.

Table 5

Water repellent supply method Overall average water absorption value, % Total standard deviation of water absorption, in PP Method No. 1
(regular feed) 3.5585 0.9842 using a dispersing device 2.9757
(down by 0.5828) 0.4314
(less by 0.5528 or 2.28 times)

The uniqueness of the invention of the method of introducing organosilicon liquid lies in the dispersion (separation into very small particles) of the organosilicon liquid by spraying under high pressure into the mixing water, in which an emulsion is formed immediately before being fed into the mixing unit.

Our proposed new method of dosing a technological additive - the formation of an emulsion of an organosilicon polymer (water repellent) using a dispersing device directly in the mixing water before dosing the gypsum binder makes it possible to evenly distribute the water repellent in the form of microdroplets in the mass of the gypsum solution, increasing its homogeneity. This makes it possible to increase the quality indicator of the finished product of gypsum tongue-and-groove slabs - water absorption (according to GOST 6428-2018) throughout the entire volume of pouring at a constant rate of water repellent consumption, as well as to reduce the number of defects on the surface of gypsum tongue-and-groove slabs at the same rate of consumption of water repellent.

Claims (2)

1. A method of volumetric hydrophobization of building products at the production stage with an automatic control mode of the molding machine, including the addition of a water repellent - an organosilicon polymer - into the mixing water before dosing the mineral gypsum binder by jointly dosing water and the water repellent in a weighing water dosing tank and mixing until a homogeneous mass is obtained, with subsequent supply of the resulting mass to the mixing unit for mixing with dosed mineral gypsum binder and obtaining a molding solution of building products, characterized in that a dispersing device with a pump and high-pressure nozzles is used to supply the water repellent, and the water repellent is supplied to the water weighing tank by a high-pressure pump through a high-pressure pipeline by means of high-pressure nozzles located on a suspension frame at the bottom of the water dosing tank, while the high-pressure pump is supplied with a control unit, the input of which is connected to the main control panel of the molding machine, and the output is connected to the electric drive of the high-pressure pump through the pump operating time relay. 2. The method according to claim 1, characterized in that the water repellent is passed through a coarse filter before being supplied to the high-pressure pump.