RU2535317C1 - Cellular concrete mixture producing method - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: as per analysis of dynamics of the mixture temperature from lime loading to mixture unloading from a mixer, a new value of weight of the batched lime for the next batch is calculated.

EFFECT: prompt correction of weights of components of a cellular concrete mixture for the next batch at change of lime enthalpy.

2 dwg

Description

The invention relates to the production of building materials, in particular, can be used in the manufacture of cellular concrete.

A known method for the operational appointment of the formulation of aerated concrete mix / Zhernakov NI, Myasnikov VN, Kozyuk MF RF patent for the invention No. 2237040 / [1]. This method analyzes the temperature of concrete in the mass before cutting and the enthalpy determined by the express method, as well as adjusting the content of components using a computer whose microprocessor is programmed based on the experimental dependence of the temperature of concrete in the mass on the content of lime at specified lime enthalpy values, as well programmed.

For reasons that impede the achievement of the following technical result when using the known method, include the fact that the known method has great complexity. In addition, the process of analyzing the temperature of concrete in the massif is determined before it is cut, which does not provide a sufficiently quick correction of the formulation of the mixture to change the lime enthalpy.

The closest method of the same purpose to the claimed method according to the totality of features is the method of production of aerated concrete mixture / Patent 2474493 Russian Federation, IPC V28C 5/00. Method for the production of aerated concrete mixture [text] / Galitskov S.Ya., Galitskov KS, Storozhenko GS, Shlomov SV; applicant GOUVPO "Samara State University of Architecture and Civil Engineering" / Application 2011130017 priority 07/19/2011; publ. 02/10/2013, Bull. No. 4 / [2]. In this method, an analysis of the change in the discharge temperature is carried out, the deviation coefficient of the maximum temperature during the exposure of the mixture is determined. Using this coefficient, the weight value of the dosed lime for the next batch is calculated. This method is adopted as a prototype.

The reasons that impede the achievement of the technical result indicated below when using the known method include the fact that in the known method the lime mass is adjusted based on the discharge temperature of the mixture, but the dynamics of lime slaking during the batch is not taken into account, for this reason, an error determination of the deviation coefficient is possible the maximum temperature during the exposure of the mixture, which does not provide a sufficiently fast accurate correction of the formulation of the mixture to change the enthalpy ty.

The essence of the invention is to improve the quality of cellular concrete products and reduce the time to adjust the masses of the components of the mixture in the production of cellular concrete mixture.

The technical result - improving the quality of cellular concrete products, operational adjustment of the masses of the components of the cellular concrete mixture for the next batch with a change in the enthalpy of lime.

The specified technical result in the implementation of the invention is achieved by the fact that in the known method for the production of aerated concrete mixture, which includes preparing and mixing Portland cement in a mixer, lime of mass m ₀ with a known enthalpy value of k ₀ , gypsum, water, a siliceous component of the reverse sludge, aluminum powder, measuring the temperature of the mixture during mixing, unloading the mixture from the mixer into the mold with subsequent exposure, additionally experimentally determine the beginning of the moment of lime loading t = 0 , determine the temperature of the mixture at the time of loading of lime T _CM.START (t = 0), calculate the temperature change T _FROM (t) = T _CM (t) -T _CM.START (t = 0), its first and second time derivatives dT _FROM / dt and d ² T _FROM / dt ² , compare the value of d ² T _FROM / dt ² with zero, determine the time t = t ₀ when the second derivative is zero, fix the value of T _FROM (t ₀ ), dT _FROM / dt | _t0 moment of time t = t ₀ , determine the value of T ₃ by the expression: T ₃ = T _FROM (t ₀ ) / dT _FROM / dt | _t0 , calculate the values of the time constants T ₁ and T ₂ from the solution of the system of equations:

$$\{\begin{array}{c}{T}_3=\frac{T_2-T_{\mathrm{one}}+T_{\mathrm{one}}{e}^{-\frac{t_0}{T_{\mathrm{one}}}}-T_2{e}^{-\frac{t_0}{T_2}}}{e^{-\frac{t_0}{T_2}}-e^{-\frac{t_0}{T_{\mathrm{one}}}}},\\ {\mathrm{<figure-callout\; id="0"\; label="t"\; filenames="00000019.png"\; state="\{\{state\}\}">t</figure-callout>}}_0=\frac{T_{\mathrm{one}}{T}_2}{T_{\mathrm{one}}-T_2}\ln \frac{T_{\mathrm{one}}}{T_2};\end{array}$$

determine the value of the enthalpy of lime by the expression:

, $$k=\frac{T_{\mathrm{AND}3}\left(t_0\right)}{m_{\mathrm{AND}3}}\left(\mathrm{one}+\frac{T_{\mathrm{one}}}{T_2-T_{\mathrm{one}}}{e}^{-\frac{t_0}{T_{\mathrm{one}}}}-\frac{T_2}{T_2-T_{\mathrm{one}}}{e}^{-\frac{t_0}{T_2}}\right)$$

,

calculate the new value of the mass of the dosed lime m for the next batch according to the expression: m = m ₀ (k ₀ / k), the value of m is introduced into the recipe of the next batch.

The drawings show: Fig. 1 (c) shows a temperature change curve during heating of a cellular concrete mixture due to the extinguishing of lime of mass m ₀ with a known enthalpy value k ₀ . Figure 1 (b) shows its first time derivative dT _FROM / dt. Figure 1 (a) shows the second time derivative d ² T _FROM / dt ² . These curves show the time t ₀ at which the second derivative of the temperature change of the mixture is zero d ² T _FR / dt ² = 0. At this point in time, the values of the temperature change T _IZ (t = t ₀ ) and its first derivative dT _IZ / dt | _t0 , they determine the value of T ₃ by the expression: T ₃ = T _FROM (t = t ₀ ) / dT _FROM / dt | _t0 .

Figure 2 shows a functional diagram of a device for promptly adjusting the masses of mixture components for the next batch when lime enthalpy changes, where the following notation is used: multiplication unit 3, prescription unit 4, which contains lime mass setting unit m ₀ 1, batchers of the mixture components 5, mixer 6 with a sensor for measuring the temperature of the mixture - T _CM 7, the first recording unit - T _SM.NACH (t = 0) 9, the unit of the comparison device 8, the first calculation unit dT _IZ / dt 10, the second calculation unit d ² T _IZ / dt ² 11, condition block d ² T _FR / dt ² > 0 12, second b registration lock t ₀ = t, T _FROM (t ₀ ) and dT _FROM / dt | _t0 13, the third block of calculations T ₃ 14, the fourth block of calculation of T ₁ and T ₂ 15, the fifth block of calculation k 16, the division block k ₀ / k 17, the unit for setting the enthalpy k ₀ 2, the memory block 18.

Information confirming the possibility of carrying out the invention with obtaining the above technical result are as follows.

Taking into account that the dynamics of lime slaking is described by an aperiodic link of the second order:

$$W\left(p\right)=\frac{T_{\mathrm{AND}3}\left(p\right)}{m\left(p\right)}=\frac{K}{\left(T_{\mathrm{one}}p+\mathrm{one}\right)\left(T_{2}p+\mathrm{one}\right)},\left(\text{one}\right)$$

the transition characteristic of the dynamics of heat dissipation of the mixture (pigv) has the form:

$$T_{\mathrm{AND}3}\left(t\right)=\left(\mathrm{one}+\frac{T_{\mathrm{one}}}{T_2-T_{\mathrm{one}}}{e}^{-\frac{t}{T_{\mathrm{one}}}}-\frac{T_2}{T_2-T_{\mathrm{one}}}{e}^{-\frac{t}{T_2}}\right)\cdot T_{\mathrm{AND}3.\mathrm{At}\mathrm{FROM}T},\left(\text{2}\right)$$

where T _IZ.UST = k · m ₀ . By differentiating this equation twice, we obtain the first derivative of the temperature change of the mixture with time (Fig. 1b):

$$\frac{d{T}_{\mathrm{AND}3}}{dt}=\frac{\mathrm{one}}{T_2-T_{\mathrm{one}}}\cdot \left(e^{-\frac{t}{T_{\mathrm{one}}}}-e^{-\frac{t}{T_2}}\right)\cdot T_{\mathrm{AND}3.\mathrm{At}\mathrm{FROM}T},\left(\text{3}\right)$$

and the second derivative of the temperature change of the mixture with time (figa):

$$\frac{d^2{T}_{\mathrm{AND}3}}{d{t}^2}=\frac{\mathrm{one}}{T_2-T_{\mathrm{one}}}\cdot \left(\frac{\mathrm{one}}{T_{\mathrm{one}}}\cdot e^{-\frac{t}{T_{\mathrm{one}}}}-\frac{\mathrm{one}}{T_2}\cdot e^{-\frac{t}{T_2}}\right)\cdot T_{\mathrm{AND}3.\mathrm{At}\mathrm{FROM}T}.\left(\text{four}\right)$$

At the point t = t _{0 of the} inflection of the transition characteristic, the second derivative of the change in temperature of the mixture with respect to time is zero, therefore, the equality

$$\raisebox{1ex}{$\mathrm{one}$}\!\left/ \!\raisebox{-1ex}{$T_{\mathrm{one}}$}\right.\cdot e^{-{\mathrm{<figure-callout\; id="0"\; label="t"\; filenames="00000019.png"\; state="\{\{state\}\}">t</figure-callout>}}_0/T_{\mathrm{one}}}-\raisebox{1ex}{$\mathrm{one}$}\!\left/ \!\raisebox{-1ex}{$T_2$}\right.\cdot e^{-{\mathrm{<figure-callout\; id="0"\; label="t"\; filenames="00000019.png"\; state="\{\{state\}\}">t</figure-callout>}}_0/T_2}=0$$

$$e^{t_0\frac{T_{\mathrm{one}}-T_2}{T_{\mathrm{one}}{T}_2}}=\frac{T_{\mathrm{one}}}{T_2}$$

,

we prologarithm the right and left sides of the equality, as a result we get:

, $${\mathrm{<figure-callout\; id="0"\; label="t"\; filenames="00000019.png"\; state="\{\{state\}\}">t</figure-callout>}}_0=\frac{T_{\mathrm{one}}{T}_2}{T_{\mathrm{one}}-T_2}\ln \frac{T_{\mathrm{one}}}{T_2}$$

,

the value of t _{0 is} determined from the conditions of equality d ² T _FROM / dt ² | _t0 = 0.

To determine the value of T ₃ we divide the expression (2) by (3) as a result for the time t = t ₀ we get:

. $$T_3=\frac{T_2-T_{\mathrm{one}}+T_{\mathrm{one}}{e}^{-\frac{t_0}{T_{\mathrm{one}}}}-T_2{e}^{-\frac{t_0}{T_2}}}{e^{-\frac{t_0}{T_2}}-e^{-\frac{t_0}{T_{\mathrm{one}}}}}$$

.

We write a system of two nonlinear equations with two unknowns (T ₁ and T ₂ ):

$$\{\begin{array}{c}{T}_3=\frac{T_2-T_{\mathrm{one}}+T_{\mathrm{one}}{e}^{-\frac{t_0}{T_{\mathrm{one}}}}-T_2{e}^{-\frac{t_0}{T_2}}}{e^{-\frac{t_0}{T_2}}-e^{-\frac{t_0}{T_{\mathrm{one}}}}},\\ {\mathrm{<figure-callout\; id="0"\; label="t"\; filenames="00000019.png"\; state="\{\{state\}\}">t</figure-callout>}}_0=\frac{T_{\mathrm{one}}{T}_2}{T_{\mathrm{one}}-T_2}\ln \frac{T_{\mathrm{one}}}{T_2},\end{array}\left(\text{6}\right)$$

The numerical solution of this system will allow you to find T ₁ and T ₂ . Then, from the solution of the equation of the transition characteristic of the dynamics of heat generation of the mixture, the coefficient k is determined by the expression:

. $$k=\frac{T_{\mathrm{AND}3}\left(t_0\right)}{m_0}{\left(\mathrm{one}+\frac{T_{\mathrm{one}}}{T_2-T_{\mathrm{one}}}{e}^{-\frac{t_0}{T_{\mathrm{one}}}}-\frac{T_2}{T_2-T_{\mathrm{one}}}{e}^{-\frac{t_0}{T_2}}\right)}^{-\mathrm{one}}$$

.

Having determined the actual value of enthalpy k for a given batch, lime mass for the next batch is calculated as the product of the initial lime mass m ₀ by the ratio of the known enthalpy k ₀ to the actual found k: m = m ₀ (k ₀ / k). The value of m is introduced into the formulation of the mixture. The above can be done on the basis of the device for the operational adjustment of the masses of the components of the mixture for the next batch with a change in the enthalpy of lime depicted in figure 2. The device operates as follows. The lime mass setting block m ₀ 1 generates a lime mass setting signal m ₀ , which is fed to the input of the multiplication block 3, the signal from the output of the memory block 18 is received at the second input of the multiplication block 3. The output of the mixture temperature measuring sensor T _CM 7 is connected to the direct input of the block comparison device 8 and with the input of the first registration unit T _CM.START (t = 0) 9, which registers the temperature of the mixture T _CM.START before loading lime at time t = 0. The signal from the first recording unit is T _CM.START (t = 0) 9 is fed to the inverse input of the unit of the comparison device 8. At the output of the unit of the comparison device 8, a temperature change signal T _FROM (t) = T _CM (t) -T _{CM is generated.} (t = 0), which is fed to the input of the first block of calculation dT _FROM / dt 10.

In the first block of calculation dT _FROM / dt 10, the first derivative of the temperature change with time is calculated:

, $$\frac{d{T}_{\mathrm{AND}3}}{dt}=\frac{\mathrm{one}}{T_2-T_{\mathrm{one}}}\cdot \left(e^{-\frac{t}{T_{\mathrm{one}}}}-e^{-\frac{t}{T_2}}\right)\cdot T_{\mathrm{AND}3.\mathrm{At}\mathrm{FROM}T}$$

,

where T _IZ.UST = k · m ₀ . The signal from the output of the first block of calculation dT _IZ / dt 10 is transmitted to the input of the second block of calculation d ² T _IZ / dt ² 11, where the second derivative of the temperature change over time is calculated:

. $$\frac{d^2{T}_{\mathrm{AND}3}}{d{t}^2}=\frac{\mathrm{one}}{T_2-T_{\mathrm{one}}}\cdot \left(\frac{\mathrm{one}}{T_{\mathrm{one}}}\cdot e^{-\frac{t}{T_{\mathrm{one}}}}-\frac{\mathrm{one}}{T_2}\cdot e^{-\frac{t}{T_2}}\right)\cdot T_{\mathrm{AND}3.\mathrm{At}\mathrm{FROM}T}$$

.

The signal from the output of the second calculation unit d ² T _FR / dt ² 11 is fed to the input of the condition block d ² T _FR / dt ² > 0 12. When the condition d ² T _FR / dt ² > 0 is fulfilled, the signal is fed to the input of the mixture temperature measuring sensor T _CM 7 and the cycle is repeated an indefinite number of times until the condition is violated. If the conditions are violated, the signal is fed to the input of the second recording unit t ₀ = t, T _FROM (t ₀ ) and dT _FROM / dt | _t0 13, the recorder will record the following signals: time t ₀ , when d ² T _FROM / dt ² = 0; the value of the temperature change T _FROM (t ₀ ) and the value of the first derivative at a given time. The signals from the output of the second registration unit t ₀ = t, T _FROM (t ₀ ) and dT _FROM / dt | _t0 13 are fed to the input of the third block of calculation T ₃ 14, where it is calculated:

$$T_3=\frac{T_2-T_{\mathrm{one}}+T_{\mathrm{one}}{e}^{-\frac{t_0}{T_{\mathrm{one}}}}-T_2{e}^{-\frac{t_0}{T_2}}}{e^{-\frac{t_0}{T_2}}-e^{-\frac{t_0}{T_{\mathrm{one}}}}}.$$

From the output of the third block of calculation T ₃ 14, the signal is fed to the input of the fourth block of calculation T ₁ and T ₂ 15, where time constants T ₁ and T ₂ are calculated by numerically solving a system of two nonlinear equations with two unknowns T ₁ and T ₂ :

$$\{\begin{array}{c}{T}_3=\frac{T_2-T_{\mathrm{one}}+T_{\mathrm{one}}{e}^{-\frac{t_0}{T_{\mathrm{one}}}}-T_2{e}^{-\frac{t_0}{T_2}}}{e^{-\frac{t_0}{T_2}}-e^{-\frac{t_0}{T_{\mathrm{one}}}}},\\ {\mathrm{<figure-callout\; id="0"\; label="t"\; filenames="00000019.png"\; state="\{\{state\}\}">t</figure-callout>}}_0=\frac{T_{\mathrm{one}}{T}_2}{T_{\mathrm{one}}-T_2}\ln \frac{T_{\mathrm{one}}}{T_2},\end{array}$$

From the output of the fourth block of calculation T ₁ and T ₂ 15, the signal is fed to the input of the fifth block of calculation k 16, where the actual value of the enthalpy for a given batch is determined by the expression:

$$k=\frac{T_{\mathrm{AND}3}\left(t_0\right)}{m_0}{\left(\mathrm{one}+\frac{T_{\mathrm{one}}}{T_2-T_{\mathrm{one}}}{e}^{-\frac{t_0}{T_{\mathrm{one}}}}-\frac{T_2}{T_2-T_{\mathrm{one}}}{e}^{-\frac{t_0}{T_2}}\right)}^{-\mathrm{one}}$$

.

The output signal from the fifth calculation block k 16 is supplied to the second input of the division block k ₀ / k 17. The estimated value of the enthalpy k ₀ formed on the enthalpy setting block k ₀ 2 is supplied to the first input of the division block k ₀ / k 17. At the output of the division block k ₀ / k 17, a coefficient k ₀ / k is formed, which is fed to the input of the memory unit 18. The signal from the memory unit 18 is fed to the second input of the multiplication unit 3. The first input of the multiplication unit 3 is connected to the output of the lime mass setting unit m ₀ 1, forming a signal that determines the value of the mass m ₀ . Therefore, at the output of the multiplication block 3, a signal is formed that determines the lime mass value m = m ₀ (k ₀ / k), which is fed to the input of the prescription unit 4.

The output of the prescription unit 4 is fed to the input of the dispensers of the components of the mixture 5, the output of which is connected to a mixer 6 equipped with a sensor for measuring the temperature of the mixture T _CM 7.

This leads to the fact that the temperature of the mixture during the unloading of the next batch approaches the value of the temperature of the mixture required by the production technology of aerated concrete mixture for the correct formation of an array of aerated concrete.

The claimed method allows you to automatically quickly specify the value of the mass of lime in the formulation in the production of aerated concrete mixture.

Using the inventive method, the quality of production of cellular concrete products is improved due to the stabilization of the temperature regime during the extinguishing of lime and the time for adjusting the mass of the mixture components is reduced.

Information sources

1. Pat. 2237040 Russian Federation, IPC 7 С04В0 38/02. The method for the operational appointment of the formulation of aerated concrete mix / Zhernakov N.I. Butchers; Applicant and patent holder of OJSC “Cottage”. - No. 2002110345/03.

2. Patent 2474493 Russian Federation, IPC В28С 5/00. Method for the production of aerated concrete mixture [text] / Galitskov S.Ya., Galitskov KS, Storozhenko GS, Shlomov SV; applicant GOUVPO "Samara State University of Architecture and Civil Engineering" / Application 2011130017 priority 07/19/2011; publ. 02/10/2013, Bull. Number 4.

Claims (1)

Method for the production of aerated concrete mixture, including the preparation and mixing of Portland cement in a mixer, lime weighing m₀ with known enthalpy k₀, gypsum, water, the siliceous component of the return sludge, aluminum powder, measuring the temperature of the mixture in the mixer during mixing, unloading the mixture from the mixer into the mold with subsequent exposure, characterized in that it further experimentally determines the start of the lime loading moment t = 0, determines the temperature mixture at the time of loading of lime T_SM.START(t = 0), calculate the temperature change T_OF(t) = T_CM(t) -T_SM.START(t = 0), her first and second time derivative dT_OF/ dt and d²T_OF/ dt²compare the value of d²T_OF/ dt² with zero, determine the time t₀= t, when the second derivative is zero, fix the value of T_OF(t₀), dТ_OF/ dt |_t0 at time t = t₀determine the value of T₃ by expression: T₃= T_OF(t₀) / dT_OF/ dt |_t0calculate the values of the time constants T_one and T₂ from solving a system of equations:
$$\{\begin{array}{c}{T}_3=\frac{T_2-T_{\mathrm{one}}+T_{\mathrm{one}}{e}^{-\frac{t_0}{T_{\mathrm{one}}}}-T_2{e}^{-\frac{t_0}{T_2}}}{e^{-\frac{t_0}{T_2}}-e^{-\frac{t_0}{T_{\mathrm{one}}}}},\\ t_0=\frac{T_{\mathrm{one}}{T}_2}{T_{\mathrm{one}}-T_2}\ln \frac{T_{\mathrm{one}}}{T_2};\end{array}$$

determine the value of the enthalpy of lime by the expression:
$$k=\frac{T_{\mathrm{AND}3}\left(t_0\right)}{m_{\mathrm{AND}3}}\left(\mathrm{one}+\frac{T_{\mathrm{one}}}{T_2-T_{\mathrm{one}}}{e}^{-\frac{t_0}{T_{\mathrm{one}}}}-\frac{T_2}{T_2-T_{\mathrm{one}}}{e}^{-\frac{t_0}{T_2}}\right)$$

,
calculate the new value of the mass of the dosed lime m for the following batch according to the expression: m = m₀(k₀/ k) the value of m is introduced into the recipe of the next batch.

Images