RU81258U1 - DEVICE FOR DESTRUCTION OF THE SURFACE LAYER OF PRODUCTS FROM ARTIFICIAL MATERIALS AND NATURAL STONE - Google Patents

Abstract

The device is intended for the destruction by electric discharges of the surface layer of products made of artificial conductive materials and natural stone and can be used in repair and construction work at airfields, nuclear facilities, and in the processing of natural stone. High voltage (1) and grounded (2) rod electrodes located in the same plane and fastened by upper (4) and lower (5) holders are made with an insulating coating (3), and all electrodes and their insulating coatings are made of flexible and elastic material, and upper and lower holders with the possibility of adjustable movement along the guides (6) along the electrodes. To prevent the destruction of insulating coatings (3), shields are installed at their lower ends by shields (8). Grounded (2) or grounded and high voltage (1) electrodes are made in the form of tubes and are arranged in several rows. The length of the bottom-hole bare part of each electrode is not more than 0.3 from the distance between two adjacent bipolar electrodes (1 and 2), which prevents their unacceptable rapprochement or shorting. 4 s.p. f-ly, 3 ill., 1 ave.

Description

The utility model relates to the field of destruction by high-voltage discharges of the surface layer of products from non-conductive materials (concrete, asphalt concrete, ceramics, rocks, etc.), and can be used in repair and construction works, at airfields, roads, in mining when processing natural stone etc.

A device for removing the surface layer of hardened concrete (USSR author's certificate No. 153827; IPC V08V 03/10, B63J 05/00, published in 1963, bull. No. 7) electrohydraulic shocks received from arresters placed in the reflector, which is made in the form of a movable elastic dielectric bowl in contact with the surface to be treated with a thickened rim and equipped with a metal cap to which water supply and current-carrying electrodes are attached.

The main disadvantage of this device is the possibility of its use only in the relatively energy-intensive electro-hydraulic method of destruction of solids, in which high-voltage discharges develop in water between the electrodes raised above the destructible surface, and inapplicability in the electric pulse method. In the electric pulse method, in which the energy consumption is much lower than in the electro-hydraulic method, high-voltage discharges develop directly in the destructible layer between the ends of the electrodes, which are constantly touching the destructible material. After the first discharges, the treated surface becomes uneven, since the depth of spalling funnels (recesses) in the electric-pulse method is on average 1/3 of the interelectrode

distances, and electrodes falling in irregularities, prevent the device from moving on the surface of the product.

A device-analogue for the destruction of concrete by the electric pulse method (USSR author's certificate No. 730034, IPC 5 Е21С 37/18, publ. 10/30/93 bull. No. 39-40) is known, which includes a housing to which electrodes located in parallel rows are attached, in the lower part of which there are lateral flushing holes directed along the electrode placement line in one direction. The device is designed for trenching by cutting parallel slots and leaving pillars between the slots. The distance between the parallel rows exceeds the distance between the electrodes in the rows by more than 1.6 times.

The main disadvantage of this device when used to destroy the surface layer of products is that it cannot be moved on an uneven surface. Since this does not allow a rigid electrode system to be made due to the working ends of the electrodes falling into spalling funnels formed during the development of discharges in the surface layer of the products. Its second drawback is that water cannot be used as a washing liquid due to the design features of the electrode system. The device is applicable only when using dielectric flushing liquids (transformer oil, diesel fuel, etc.), since neither high-voltage nor grounded electrodes have insulation coatings, and when using conductive liquid (water, etc.), significant energy losses occur leakage current account.

The second drawback is eliminated in the prototype device intended for the destruction (cutting) of rocks and artificial non-plastic materials by high-voltage discharges developing in a destructible surface (Bazhov V.F., Zhurkov M.Yu., Lopatin V.V., Muratov V.M. . "Electric-discharge cutting of rocks." Journal "Physicotechnical

problems of mining ", 2008, No. 2, p. 70-71, Fig. 1, b). The main structural elements of this known device are rod high voltage and grounded electrodes, each of which is equipped with an insulating coating. In the upper and lower parts, the electrodes are fastened by dielectric holders made in the form of plates with holes through which the electrodes are passed. In the area between the upper and lower holders, all electrodes are in a monolithic common insulator made of epoxy compound. The bottomhole end of each electrode is equipped with a spring loaded tip.

The disadvantage of the prototype device is that it does not provide constructive solutions that allow you to move it on the destructible surface in the process of supplying high-voltage pulses, since it is designed to work in the following order: installing the device on the surface to be processed, destroying it to a predetermined depth by electric discharges, the cessation of the supply of electrical impulses, the rearrangement of the device on the part that is not processed by discharges, and so on the entire surface, resulting repeated permutations significantly increases the time of destruction of the surface layer.

The technical result of the proposed device is to reduce the time of destruction of the surface layer of products (more than 20%), as it constructively solved the problem of continuous movement of the device on the destructible surface.

The specified technical result is achieved by the fact that the device for destroying the surface layer of articles made of artificial materials and natural stone by electric discharges, containing alternating high-voltage and grounded rod electrodes located in the same plane and fastened by upper and lower holders, each of which is made with an insulating coating, according to the proposed solution equipped with guides, electrodes and their

insulation coatings are made flexible and elastic, and the lower holder with the possibility of adjustable movement along the guides along the electrodes.

It is advisable to provide the lower ends of the insulation coatings with protective shields.

In addition, in the device, the length of the bottom-hole exposed part of each electrode is not more than 0.3 from the distance between two adjacent bipolar electrodes.

It is also advisable to grounded or grounded and high voltage electrodes to perform in the form of tubes.

In addition, it is advisable to arrange the electrodes in several rows.

An example of a specific implementation of the proposed device is illustrated in three figures. Figure 1 shows its front view, figure 2 shows a section through a grounded electrode, figure 3 shows a section, as in figure 2, but in the process of operation of the device.

The device consists of alternating high-voltage rod 1 and grounded 2 electrodes located in one plane, each of which is made with an insulating coating 3. The electrodes are fastened by the upper 4 and lower 5 holders, which are made in the form of plates with through holes for the electrodes. In the lower holder 5, the lower ends of the guides 6 are fixed, and their upper ends are freely passed through the upper holder 4. To fix the guides 6 at a given height, screws 7 are provided in the upper holder 4. To prevent destruction by discharges, the lower ends of the insulating coatings 3 of all electrodes are made with protective shields 8. High-voltage electrodes 1 are made of metal rods, and grounded 2 of conductive tubes. The upper ends of the high-voltage electrodes 1 are electrically connected by a bus 9. The upper ends of the grounded electrodes 2 are connected to the grounded washing pipe 10. To increase the washing intensity, the high-voltage electrodes 1 are also

can be made of tubes and attached to the flushing system. All electrodes are made of spring steel, the insulating coatings 3 are made of vacuum rubber, the holders 4 and 5, and the guides 6 are made of fiberglass. The length of the bottom-hole bare part of each electrode L (Fig. 1) of the device intended for work on concrete surfaces is 25 mm, and the distance between two adjacent bipolar electrodes (with a diameter of 8 mm) is 90 mm. The workpiece 11 (figure 3) is placed in a polyethylene tank 12 filled with water 13. If necessary, remove the surface layer of the product to a considerable depth for a one-time movement of the device in one direction, the number of electrodes is increased, placing them in several rows.

The work of the proposed device is as follows. Concrete product 11, 300 mm long, 530 mm wide and 300 mm high, is placed in a tank 12 filled with water 13. A device is installed vertically on the product, guides 6 are fixed in screws in the upper holder 4 and into the grounded flush pipe 10 as a flush liquids supply industrial water in an amount of 30 l / min. The water level 13 in the tank 12 is maintained above the protective shields 8. The high voltage electrodes 1 are supplied with pulses of voltage U (t) = 320 kV with a frequency of 4-5 pulses per second, and at the same time the device is moved in the x direction at a speed of 23 mm / s. In one cycle (the passage of the device), the surface layer of the concrete product 11 is destroyed to a depth of 26-34 mm with a breakable strip width of 410-420 mm and a length of 600 mm. If it is necessary to destroy the surface layer to a greater depth, the device is moved in the opposite direction and so on. The device is operable even in the absence of washing, but with less efficiency, since in this case part of the discharges develops not in the surface layer of the product, but in the formed particles of sludge located between the exposed ends of electrodes 1 and 2 (Fig. 1). Due to the fact that

high-voltage 1 and grounded 2 electrodes and their insulating coatings 3 are made flexible and elastic, they bend when the ends of the electrodes hit the protruding irregularities of the destructible surface layer of the product 11 and straighten after these irregularities. The same thing happens when you move the device in the opposite direction. This allows you to avoid device stops on protruding irregularities or breakdowns, as was the case when testing the prototype device when it destroyed the surface layer of a concrete product with large gravel filler. However, the possibility of deviation of the electrodes 1 and 2 from the initial position (figure 1) on the protrusions, unevenness of the product should be limited, since with significant bending, the distance between adjacent bipolar electrodes can decrease so that all discharges will occur only between the approaching electrodes. With a significant increase in this distance, electric discharges will not develop from single deflected electrodes. To avoid this, experimentally determine the location of the lower holder 5 depending on the material of the product. So, for homogeneous sandstone on calcareous cement, the location of the lower holder 5 is not particularly important, but for coarse-grained granite, concrete with coarse filler, it is necessary to select the location of the lower holder 5, lowering it along the guides 6. We experimentally established that in boundary conditions ( the lower holder 5 is located in its lowest position) for the reliability of the process of removing the surface layer of the products, the length of the bottom-hole exposed part of each electrode should be no more than 0.3 from the distance ence between two neighboring electrodes of different polarities 1 and 2, since in this case the electrodes can not get close to such a distance, when all bits occurring in the same place.

Claims (5)

1. Device for destroying the surface layer of articles made of artificial materials and natural stone by electric discharges, containing alternating high-voltage and grounded rod electrodes located in the same plane and fastened by upper and lower holders, each of which is made with an insulating coating, characterized in that the device is equipped with guides , the electrodes and insulating coatings are flexible and elastic, and the lower holder with the possibility of adjustable movement along the guides along electrodes. 2. The device according to claim 1, characterized in that the lower ends of the insulating coatings are provided with protective shields. 3. The device according to claim 1, characterized in that the length of the bottom-hole exposed portion of each electrode is not more than 0.3 distance between two adjacent bipolar electrodes. 4. The device according to claim 1, characterized in that the grounded or grounded and high voltage electrodes are made in the form of tubes. 5. The device according to claim 1, characterized in that the electrodes are arranged in several rows.