M.V. Grishin, Cand. Sci. (Eng.), Head of the Laboratory, mvgrishin@gmail.com V.A. Uvarova, Dr. Sci. (Eng.), Head of the Department P.M. Grishin, engineer AO «NTs VostNII», Kemerovo, Russia S.A. Prokopenko, Dr. Sci. (Eng.), Leading Researcher National Research Tomsk Polytechnic University, Tomsk, Russia
On the basis of the results of accidents investigation it is shown that the discharge of static electricity, which is accumulated on the surfaces of products from polymeric materials, can become the source of methane ignition at the mine. Non-compliance of the current normative documents requirements with the main criteria of electrostatic safety (surface resistance and specific surface resistance) and dependence of these criteria on air humidity are established. The article specifies the need in accounting hazard of electric charges accumulation on the power cable sheath laid in the mines and carrying out additional researches for justification of their electrostatic safety.
For decrease in surface resistance of mining products and equipment it is proposed to use coverings from polymeric metal-containing nanocomposites, which are received by joint sedimentation of metal vapor with its subsequent polymerization. Other method — application of electrically conductive coatings or electrically conductive surface on the products polymeric surface. It is noted that for the number of products the measurement of surface resistance is complicated due to absence of the required flat platform for installation of electrodes and metal parts presence. Alternative methods of assessment of electrostatic safety are proposed.
Examples are considered related to the use of new non-uniform polymeric materials, and also the materials with internal threads of specific form with sharp edges. It is established that the most effective method of their electrostatic safety can serve the test on ignition of explosion hazardous medium sample in the field of emergence of these discharges by means of the special probe of ignition.
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