SU1641622A1 - Method for plasma treatment of electrically non-conducting materials - Google Patents

Abstract

The invention relates to the plasma surface treatment of products from non-conductive materials and can be used in the construction industry for the production of reinforced concrete and aerated concrete products with factory finish. The purpose of the invention is to improve the quality of processing. The invention provides for maintaining the anode distance 4 - the axis of the plasma torch 3 at the time of excitation of the plasma jet within the limits of Vozb (0.05-0.1) D, and during the burning of the plasma jet - within the Mountains (0.7-1.5) 0, where D is the diameter of the plasma jet. 1 ill., 1 tab.

Description

The invention relates to a plasma surface treatment of products from non-conductive materials and can be used in the construction industry for the production of reinforced concrete and aerated concrete products with factory finish.

The aim of the invention is to improve the quality of processing.

The method of plasma processing non-conductive materials with a plasma jet is that the distance between the cathode of the plasma torch and the anode is set during the excitation of the plasma jet in the range of (0.05-0.2) D, and during combustion, in the range of (0.7-1 , 5) D, where D is the diameter of the plasma jet.

The drawing shows a device for implementing the method.

The plasma jet 1 is periodically excited and supported between the cathode 2 of the plasma torch 3 and the anode 4 located outside it, which are moved together above the surface 5 of the product 6 in separate sections 7 according to a predetermined program. At the moment of excitation of the plasma jet 1, the distance I between the axis of the plasma torch 3 and the anode 4 is set within 1 _V cb = (0.0502) D, and during the combustion of plasma jet 1 over sections 7 of surface 5, this distance is maintained within Irop = (0 , 71.5) D according to the invention.

Processing of individual surface sections according to a given program in the regime of repeatedly-briefly temporary burning of a plasma jet requires its reliable excitation at strictly defined points in time. The quality of processing and the decorative properties of the treated surface depend on the degree of reliability of the excitation of the jet. If, for example, a plasma jet is not excited at a certain point in time, the corresponding section will be partially unprocessed and the figure as a whole will be incomplete. Reliable excitation of the jet takes place only under strictly defined conditions, namely, at distances between the anode 4 and the axis of the plasma torch 3 1ex = (0.05-0.2) D, where D is the diameter of the plasma jet. If 1 _In cb <0.05 O. then when the jet is excited, the anode spot attachment point is located at the point of the anode closest to the plasmatron, the jet hits the anode, destroying it, and the products of anode erosion are transferred to the surface of the product, reducing its decorative properties. If! Exc> 0.2D, then the reliability of the excitation of the jet decreases, namely: the probability of excitation W of the jet with a single power-up is always less! ceteris paribus (jet power P, distance the nozzle of the plasma torch anode L, etc.). Thus, at the moment of excitation of the plasma jet, it is necessary to ensure! Exc = (0.05 ~ 0.2) D. However, at such distances I, during jet burning, increased anode erosion is always observed. In this case, already after 10–2.0 inclusions, the distance I due to the destruction of the working end of the anode becomes more than 0.2D, which leads to a sharp decrease in the reliability of the excitation of the jet. Stable burning of a plasma jet, in contrast to its excitation, is possible at large distances I.

The table shows experimental data showing that if, after excitation of the jet, the distance I is even brought to a value of 1.5 D, its combustion mode is not violated. At Irop> 1.5D, the plasma jet spontaneously extinguishes. The minimum value of Irop, at which it is advisable to maintain the combustion of a plasma jet, is established on the basis of measurements of the linear erosion of the anode.

An additional criterion is the absence of the so-called double arcing, when several visually observed points of attachment of the anode spots are formed on the surface of the anode, which leads to a sharp increase in linear erosion.

Thus, reliable excitation and combustion of a plasma jet in the intermittent mode is ensured at _{18 8} os = (0.05-0.2) D and l _rO p = (0.7-1.5) 0, respectively. At the same time, anode service life acceptable in real production conditions is achieved: approximately 8-10 hours of clean time and high quality of processing: all areas provided by the program are completely melted, the products of anode erosion due to their small amount are not visually fixed on the surface.

Claims (1)

Claim A method for plasma treatment of non-conductive materials with a plasma jet that is excited and supported during combustion between the plasma torch cathode and the anode placed at a distance from it, characterized in that, in order to improve the quality of processing, the distance between the plasma torch cathode and the anode is set during the plasma jet excitation in within (0.05-O, 2) D, and during combustion, within (0.7-1.5) D, Where D is the diameter of the plasma jet. Linear erosion of the anode Δ during burning of a plasma jet (Mode: P = 40 kW, L = 10-30 mm, Ovozd. = 6 m ³ / h) I / O rel. od. A mm / h Note 0.5 4.31 4.0 ( Double arcing, drop in heat transfer to 0.6 surface due to increased heat loss to the anode: anode erosion products fall on the surface of the product 0.7 0.8 1.2Ί ..--: - 1,1 | • 0.9 0.9 ’ Steady burning of a plasma stream 1,2 0.8 < " 1,5 0.8 j 1.6 0.8 Unstable burning, spontaneous extinction 1.7 - J plasma jet