RU2228316C2 - Method of treating cement mortars - Google Patents

Abstract

FIELD: manufacture of building materials. SUBSTANCE: invention relates to geological prospecting, oil production, and mining industries and can be used for treating and activating cement mortars as well as clay-cement and grouting mortars, and drilling muds. Activation comprises treatment of cement mortars by alternate high-voltage electric disruptions of interelectrode gap and pulse currents spreading out in mortar, number of electric disruptions constituting 40-50% of the total number of imposed pulses. Additional treatment is performed by charging current. This current is measured in at least two points of mortar equidistant from interelectrode gap and, when measured currents are equal, treatment is stopped. EFFECT: reduced power consumption and treatment time due to decreased number of pulses. 1 dwg, 1 tbl

Description

The invention relates to exploration, oil and mining industries and can be used for the treatment of cement mortars, as well as clay, cement, grouting and other types of drilling fluids.

A known method of processing cement mortars (AS USSR No. 587238, IPC E 21 B C 04 B 33/138, prior of July 4, 73), in which the solution is exposed to powerful shock waves arising due to high-voltage pulse discharges between high-voltage and grounded electrodes with energy of a single pulse from units to tens of kilojoules.

The disadvantage of this method of processing cement mortars is the insufficiently high efficiency of the process of activation of cements, which leads to high energy costs.

The closest in technical essence to the present invention is the method of processing cement mortars chosen by us for the prototype by exposure to high-voltage electric pulses (AS USSR No. 1225218, IPC C 04 V 40/00, publ. 30.08.94), in which cement mortar is placed in a chamber with built-in electrodes, acted by electric pulses with parameters that provide electric breakdown of the interelectrode gap for 40-50% of pulses, and for the remaining pulses - spreading of pulsed currents in the processing solution without breakdown between the electrodes.

The disadvantages of this method are the long processing time and high energy consumption. This is due to the fact that pressure sensors monitor the process of processing cement mortar by the amplitude of the shock waves only for 40-50% of the total processing time of the mortar, i.e. when the breakdown of the interelectrode gap occurs, and at the time when there is no breakdown, the solution is affected only by the spreading of pulsed currents. Then there is no information on the progress of the process. Thus, there is no continuous information on the progress of the cement mortar treatment process by pulsed electric discharges, which leads to an increase in the time of its conduct and the waste of energy.

The main technical task of the invention is to reduce energy consumption and reduce processing time by reducing the number of pulses. The reduction in energy and the number of pulses in comparison with the prototype allows to reduce energy consumption and processing time of the cement mortar in 1.14 times.

The main technical problem is achieved by the fact that in the method of activating a cement mortar, including processing it with alternating high-voltage electrical breakdowns of the interelectrode gap and pulsating currents spreading in this solution with the number of electrical breakdowns 40-50% of the total number of supplied pulses, according to the proposed additional charge charging treatment charge current is measured at least at two points of the solution equidistant from the interelectrode gap, and if equal, we measure x current processing is terminated.

Concrete example

The drawing shows a diagram of the installation for implementing the method of processing cement mortars with high voltage electric pulses. The installation is made in the form of a charger consisting of a high-voltage transformer 1 and a rectifier 2 connected to a pulse generator, represented by a capacitor bank 3 and a ball spark gap 4. In the working chamber 5 are high-voltage electrodes 6 and 7, one of which 6 is connected to a capacitor bank, and the other 7 is grounded. In the working chamber 5 there are also measuring electrodes 8, which are connected to the current sensor 9 through a protective inductance 10. In parallel with the current sensor, a protective shunt resistance is put 11. There is also a pulse counter 12.

For a specific implementation of this method, the capacitance of the capacitor bank 3 is C - 0.5 μF, the pulse amplitude is 60 kV, the interelectrode gap is 15 mm, and the pulse frequency is 6 Hz. Additional measuring electrodes 8 were placed opposite each other perpendicular to the interelectrode gap at an equal distance from it, a distance of 15 cm. A cement grout of cement is used in industrial water with a specific resistance of 3 · 10 ³ Ohm · cm. The specific gravity of the cement mortar is 1.85 g / cm ³ . The volume of the solution is 30 l.

The method is as follows. The prepared cement mortar is poured into the working chamber 5. Then, the installation is turned on and the capacitor bank 3 is charged to the voltage required for the breakdown of the air ball gap 4. In this case, the solution in the working chamber 5 is subjected to an activating effect of the charging current. After the voltage on the capacitor bank reaches the breakdown voltage of the ball gap 4, it is triggered and the solution is processed by high-voltage electrical pulses. In this case, the energy parameters of the pulses are chosen such that for 40-50% of the pulses would provide an electrical breakdown of the interelectrode gap, and for the remaining pulses, the spreading of pulse currents in the processed solution without breakdown between the electrodes 6 and 7. Thus, in one working chamber 5 there are three mechanisms of action on the solution being treated, namely, treatment of the solution with the charging current of the capacitor bank 3 pulse generators, hydrodynamic shocks that occur during breakdown of the solution, and the effect of and the working medium with spreading pulsed currents. Using the counter 12, the number of pulses is calculated and the value of the charging current of the capacitor bank 3 flowing through the cement solution is recorded using measuring electrodes 8 connected to the current sensors 9. If the readings of the current sensors 9 are equal, the processing is stopped. The processing efficiency is evaluated by the bending strength of cement stone.

As a result, a relationship was established between the difference in the readings of the current sensors 9 and the properties of cement stone, which is presented in the table:

The table shows that when the readings of the current sensors 9 were equal, the bending strength of the cement stone was maximum, and if the difference in readings is non-zero, then the strength of the cement stone is significantly lower than the maximum value. The difference in the readings of the current sensors 9 became equal to zero, after 1050 pulses were supplied and during further processing, this state remained, similarly, the strength of the cement stone reached its maximum when processing the solution with 1050 pulses and remained almost unchanged during further processing. It follows that the relationship between the difference in the readings of the current sensors 9, recorded at two points of the chamber 5 with the aid of measuring electrodes 8, the values of the charging current of the capacitor bank 3 and the properties of the cement stone is established, which makes it possible to establish in time the end of processing.

For comparison, the cement mortar was processed in a similar manner by the prototype method, when processing 30 liters of mortar, 1200 pulses were required, while the strength of the cement stone was 76.7 kg · s / cm ² . The duration of the process and the energy consumption during processing were determined by the energy of a single pulse of 900 J and the number of pulses supplied.

Thus, the number of pulses with the same properties of the treated solution is reduced by 150 pulses, the total energy consumption for processing the cement mortar according to the claimed method is 94.5 · 10 ⁴ J, and according to the prototype method, the energy consumption was 108 · 10 ⁴ J.

Therefore, the energy consumption for processing the cement mortar and the processing time by the claimed method is 1.14 times less than the prototype.

Claims (1)

A method of activating a cement mortar, including its processing by alternating high-voltage electrical breakdowns of the interelectrode gap and pulsed currents spreading in this solution, with the number of electrical breakdowns of 40-50% of the total number of supplied pulses, characterized in that additional processing with a charging current is carried out, the charging current is not measured less than two points of the solution equidistant from the interelectrode gap and when the measured currents are equal, the processing is stopped.