SU1543324A1 - Method of impregnating carbon articles - Google Patents

Abstract

The invention relates to the production of carbon materials, in particular methods of impregnation. The aim of the invention is to stabilize the properties of manufactured carbon products. The electrical resistance of the workpiece is preliminarily measured, then placed in an impregnate, held in an impregnate at the impregnation temperature, measured by electrical resistance, until its established value is obtained. After that, the impregnation is carried out according to the required mode, controlling the electrical resistance, according to which the impregnation parameters are judged. 5 il.

Description

The invention relates to methods for producing carbon materials, in particular to methods for producing their impregnation with carbonized impurities, in particular coal tar pitch.

The purpose of the invention is to stabilize the properties of manufactured carbon products.

The method of impregnating carbon products is that the products are placed in an airtight chamber, heated to a predetermined temperature, vacuumized to remove air from the products. The product is connected to an electrical resistance meter and the air removal process is carried out until a constant electrical resistance is obtained. The products are filled with im- pregnat, re-evacuated and, after removing residual air, an overpressure is created in the chamber for the time required for impregnation.

The invention is illustrated in the drawings, where in FIG. 1 shows the installation of impregnation; in fig. 2 - sequence in time Ј application of pressure P during impregnation; in fig. 3 the change in electrical resistance R at holding b at the impregnation temperature; in fig. k is the change in electrical resistance K when pumping and pressure drop -P; in fig. 5 is the same in the actual impregnation process after application of the full working pressure, i.e. R dependence on 7.

An installation for implementing the method comprises a vacuum chamber 1 with a door 2 in which two coaxial tanks 3 and k are placed. The vacuum chamber 1 is provided with a heater 5 placed in its housing. In the bottom of the upper container 3, there is a conical socket 6 for a conical plug 7, pulled out at the end of the impregnation process with

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wire 8. Capacity cover 9 with a block

material, for example, fiberglass plastic, in which the pass-through contacts 11, made, for example, of copper, are placed. A cover 12 with a thermocouple 13 is also welded to the cover 9 (composite pipe can be used to reduce heat flow from the heater and, accordingly, reduce distortion of the thermocouple signal 13) - Two perforated clips 15 with movable contacts are placed in the tank 3 on the electrically insulating base 1 16, resting on the ends of the workpiece 17. The central (axial) of the contacts 16 serve to remove the potential and they are connected to a divider from the reference resistors 18, to the arm of which through the switch 19 they connect either a dial gauge 20, l for the recorder 21. Thermocouple 13 through the switch 22 is also connected either to the switch instrument 23, or to the self-25 scribe 2. The contacts 16 are clamped to the workpiece L / using levers 25 with weights 26, with one ends hinged on the axis 27, mounted on racks 28, which are placed on base 1. Vacuum pump 31 is connected to vacuum chamber 1 through valve 29 and trap 30. The operation of heater 5 is controlled by a thyristor unit 32 according to signals from a regulating device 33 In the door 2 of the vacuum chamber l unscrewing plug 3, to which a wire 8 is attached on the inner side. To send a signal to the device 33, a thermocouple 35 embedded in the case of the vacuum chamber 1 is used. The power supply to the workpiece 17 from the source 36 is supplied through the reference resistance 37, the voltage from which the divider from the resistances 38 (also reference ones), depending on the position of the switch 39, is applied either to the pointer device 0 or to the recorder k.

The method for controlling the impregnation of carbon materials is implemented as follows.

The workpiece 17 is placed in the contacts 16 and pressed onto the ends of the workpiece with the help of levers 25 with weights 26, after which a source 3 & power and readout countdown arrows 15 332 4

3 closes the devices 20 and AO and when switching 10 from the electro 30

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using the recorders 21 and 1 using switches 19 and 39, taking into account the known values of reference resistances 18, 37, 38, the initial electrical resistance of the workpiece 17 is calculated. After this, the base} C with workpiece 17, contacts 16, arms 25 with weights 26, 27 and poles 28, placed in a container 3, rubbing in the plug 7 in the conical socket 6, and pouring melted pitch, after which the heater is turned on. During these operations and subsequent exposure, the recorders 21 and 41 continuously record the readings. through the workpiece 17 and the voltage drop across it. Comparing the electrical resistance calculated in this way with the previously measured one makes it possible to establish in the initial period the dependence of the electrical resistance on temperature, and further to register the ongoing wetting and capillary impregnation processes, as shown in FIG. 3. After reaching a steady-state value, the workpiece 17 is impregnated according to the pressure application mode shown in FIG. 2. When pumping and lowering the pressure above the pitch mirror, a change in electrical resistance occurs, as shown in FIG. And, after pressure has been applied — shown in FIG. 5. It has been established that as a result of applying a preliminary measurement of resistance (due to neglect of thermal fluctuations), as well as as a result of exposure and pumping controlled by electrical resistance, impregnation of the obtained dependences is excluded, and the difference from the actual values of electrical resistance in measurements The known methods are up to 30%, which indicates an increase in the accuracy of measurements. The extension of functionality consists in obtaining earlier unknown laws of change in electrical resistance in time and in the process of decreasing pressure during repetition: rolling.

Claims (2)

Invention Formula The method of impregnation of carbon products, which consists in that 0 five devices 20 and AO and when switching 0 five 0 five 0 five using the recorders 21 and 1 using switches 19 and 39, taking into account the known values of reference resistances 18, 37, 38, the initial electrical resistance of the workpiece 17 is calculated. After this, the base} C with workpiece 17, contacts 16, arms 25 with weights 26, 27 and racks 28, are placed in the container 3, rubbing the plug 7 in the conical socket 6, and pour it with molten pitch, after which the heater is turned on. During these operations and the subsequent exposure, the recorders 21 and 41 continuously record the readings after the workpiece 17 and the voltage drop across it. Comparing the electrical resistance calculated in this way with the previously measured one makes it possible to establish in the initial period the dependence of the electrical resistance on temperature, and further to register the ongoing wetting and capillary impregnation processes, as shown in FIG. 3. Once the set value has been reached, the preform 17 is impregnated according to the pressure application mode shown in FIG. 2. When pumping and lowering the pressure above the pitch mirror, a change in electrical resistance occurs, as shown in FIG. And, after pressure has been applied — shown in FIG. 5. It has been established that as a result of applying a preliminary measurement of resistance (due to neglect of thermal fluctuations), as well as as a result of exposure and pumping controlled by electrical resistance, impregnation of the obtained dependences is excluded, and the difference from the actual values of electrical resistance in measurements The known methods are up to 30%, which indicates an increase in the accuracy of measurements. The extension of functionality consists in obtaining earlier unknown laws of change in electrical resistance in time and in the process of decreasing pressure during repetition: rolling. Invention Formula The method of impregnating carbon products, which consists in placing the products in an airtight chamber, heating them to a predetermined temperature, vacuuming them before removing air from the products, pouring them in impregnated oil, reapplying them, and after removing the residual air, creating excessive pressure in the chamber o t characterized in that, in order to stabilize the properties of the manufactured carbon products, the product is connected to an electrical resistance meter and the air removal process is carried out to obtain a constant electrical resistance. 19 20 Fia1 /, ha about Yu 10 ohm rbo FIG. 2 200 ten ten about  I and about rbo p (/ gz zoo . -ft /, tO- "Ohm  ;