Dozór Techniczny (Technical Supervision) 2021/04

  • Vibrodiagnostics in the mining industry
    Vibrodiagnostics is one of the methods of predictive maintenance support. It consists in measuring machine vibrations and their analysis regarding the occurrence of symptoms of developing failures. For many years, it has been widely used in industries such as energy, chemical and paper industries and many others. Vibrodiagnostic methods also have a long history in opencast mining - in particular in the field of gear monitoring, and with the development of ATEX-approved technology, vibration monitoring systems are increasingly appearing in underground mining. Vibrodiagnostics in mining The ongoing transformation within Industry 4.0 and the emphasis on the use of maintenance techniques supporting Predictive Maintenance make underground mining more and more interested in the use of vibrodiagnostics as part of machine monitoring. It should be remembered that the measurement and processing of vibrations in terms of diagnostics of devices in underground mining is a challenge that has been jointly undertaken for years by mines, machine manufacturers and suppliers of diagnostic systems. The experience so far shows that due to the high variability of the operating conditions of mining machines and hardware limitations resulting from ATEX requirements, comprehensive vibrodiagnostics of devices, such as gears of mining combines and conveyors, is a much more difficult task than in other industries, but not impossible.
  • Contemporary speckle interferometry on the traces of the causes of damage under the influence of fatigue
    loads Cyclic loads causing cracks in the structure are still a current problem that requires further intensive research. The paper presents an analysis of one of the many issues related to the effects of this type of load, namely: testing the initiation of a fatigue crack in a material loaded cyclically in the elastic range based on the tests carried out with the use of speckle interferometry. It was assumed that the increase in damage occurs as a result of the average stress and its fluctuations caused by the heterogeneity of the crystal structure and the effect of the movement of free grain boundaries. Stress fluctuation areas in a polycrystalline metal subjected to mechanical loading induce a uniform increase in the average stress and strain values caused by the heterogeneity of the material related to the anisotropy of its structure. Plastic flow develops with a low level of mean stress in some grains due to local stress concentration and local accumulation of strain at their boundaries. Stress fluctuations, appearing in regions with a global value of stress below the elastic limit, are the source of initial structural defects and microplastic mechanisms, leading to an advanced state of plastic flow. The mechanism responsible for the accumulation of failures during cyclic loading at stress below the yield point is still an issue that requires further research and will not be discussed in more detail here. An attempt at analytical description of this problem and development of a coherent description of the microplastic state of the material was undertaken at the Institute of Fundamental Problems of the Polish Academy of Sciences.
  • Structures of offshore wind farms - a challenge for designers
    Obtaining wind energy is one of the most promising sources of renewable energy. The article presents issues related to the development of wind energy, including the construction of offshore wind farms. In particular, the basics of wind energy, the current state and development prospects for offshore wind farms, structural elements of offshore wind turbines and the infrastructure for transmitting energy to land were presented.
  • Explosion-proof cameras - a response to the challenges of the industrial sector
    Strict health and safety regulations and the requirements related to regular maintenance of machines force industrial entrepreneurs to search for better and better solutions to improve the control of production processes. Eliminating potential threats resulting from incorrect operation of machines, preventing production downtime and minimizing the risk of accidents resulting from human error are key challenges for operational management. The answer to them can be integrated camera systems with explosion protection, which enable remote monitoring of hazardous areas, inform about device errors and are able to prevent accidents involving people. Explosion-proof cameras are designed to eliminate the risk of a spark that could cause an explosion in a hazardous environment.
  • Remote support. Digital transformation in hazardous areas
    The challenges posed by the current pandemic, as well as staff costs and the shortage of skilled workers, are putting increasing pressure on businesses. Extensive plant maintenance is becoming more and more difficult to maintain efficiently and in line with requirements.
  • Pilz PSENscan safety laser scanner
    Additional digital inputs and outputs are now available for the PSENscan safety laser scanner: Up to 70 switchable configurations can be implemented and up to three separate safety zones can be monitored simultaneously with the new 17-pin master encoders. As a result, stationary areas can be monitored more effectively, also with the help of the new partial dynamic muting.

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