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Introduction

Because of the limited space and the large depth of underground mine workings occur harsh conditions of miners work. This leads to deterioration of labor productivity, workers' health, increased risk of injuries and accidents, and also limits the ability to conduct production processes.

Therefore, one of the most important links in a complex technological system of a mine is the process of ventilation of mine workings, the purpose of which is to maintain a normal atmosphere in the mine – to provide the necessary influx of fresh air, to ensure an acceptable concentration of methane in the mine atmosphere. Process units that perform these functions are the main ventilation fans.

The efficiency and stability of the main ventilation fan of the mine depends on the parameters of the ventilation network: total aerodynamic resistance, the required amount of air supplied to the ventilation shaft, natural draft of the network, etc. These values together with the technical characteristics of the fan determine the operating mode of the latter.

That is why the development and research of an automated process control system for coal mine airing is of great economic importance. This will improve the effectiveness and intensity of technological processes, and therefore the operation shaft in general.

1. Theme relevance

The task of automating the ventilation of mines is reduced to the supply and distribution of the amount of air in the workings, which ensures the specified performance of the faces, complies with the requirements of safety rules and hygiene standards, and maintains optimal modes of fan installations.

Features of the underground technology of excavation of minerals put forward this task in a number of the most difficult problems of mining. Safety, and often the lives of people working in the mine, depends on reliable, trouble–free operation of the ventilation system. Also in the mining industry, the drive of the fans serving the mine takes up to 8 – 10% of the electricity consumed by the entire mine.

2. Goal and tasks of the research, the planned results

The main objective of the design is to develop and study the automated system for controlling the ventilation of the coal mine, which will ensure the stable operation of this object. Regular adjustment of the fan to the network parameters should be carried out at intervals of several hours to several days. Such management requires either constant monitoring by the staff, or the introduction of an automated tracking system and stabilization of the fan performance.

Thus, the goal of the master's thesis is to increase the efficiency of the main ventilation unit of the mine, to ensure reliable, stable and economical ventilation of mine workings with a minimum deviation from the specified mode by developing and implementing a performance control unit for the fan installation with a setting for maximum efficiency.

The developed device must meet the following requirements:

3. Review of research and development

3.1 Analysis of the fan installation of the main ventilation of the mine as an automation object

Ventilating installations serving the whole shaft or its part (wing, block, panel) belong to the fan installations of the main ventilation.

fan installation of the main ventilation of mines are turbomachines – bladed machines, in which the increment of the specific energy of the transported air occurs as a result of the force interaction of the blades of the rotating impeller with the stream flowing around them. Equipped with, as a rule, two fans – working and standby [1]. The ventilation unit is equipped with a set of electrical equipment and various auxiliary mechanisms: switching winches, gearing and guide vanes, an electromagnetic fan brake, an oil pump for lubricating bearings (on large fans), etc. [2].

Figure 1 – flow chart of the fan installation of the main ventilation with a centrifugal fan

Figure 1 – flow chart of the fan installation of the main ventilation with a centrifugal fan

Figure 1 shows the following conventions: 1 – overlapping string; 2 – bypass channel; 3,8 – switching ports; 4,7 – Lyady diffusers; 5,6,9,11 – winches for rearrangement of scad; 10 – suction booth; 12 – atmospheric lada; 13 – the main channel.

3.2 Automation equipment of the main ventilation unit

The equipment for control, automation and control of a shaft fan installation is a complex of complex, cooperative systems, complemented by auxiliary devices and mechanisms [4]. Systems operate in ever-changing combinations with a specific sequence specified [5].

The main task of regulating the ventilation of the mine is to maintain a given amount of air in the mine ventilation network by changing the performance of the fan in accordance with the consumption of a certain amount of air.

For this purpose, the shaft equipped with ventilation equipment capable of providing the shaft with air to the working personnel can freely without lack of oxygen, to carry out the production process of mineral extraction and for diluting fresh air pollutant in production.

The equipment adopted as the base is UKAV–M [6], which provides the possibility of automated control of the main ventilation shaft fans, while observing all safety standards

3.3 Block diagram of the automation system of the main fan installation of the mine ventilation process

A block diagram of the automation system of a fan unit for main ventilation of the mine ventilation process is developed, which is shown in Figure 2.

Figure 2 – block diagram of the automation system of the main ventilation unit

Figure 2 – block diagram of the automation system of the main ventilation unit

In the figure marked: S – sensors; PCD – performance control device fan installation of the main ventilation; EU – execution unit; ACS – automatic control system for performance; О – operator (driver) mines; IK1 – industrial computer operator mine O; IK2 – industrial computer mine manager; М – mine dispatcher mnemonic;

Regulation of centrifugal fans is carried out by aerodynamic regulation or by regulating the speed of rotation of the fan shaft [7]. Basically, in the ventilation automation systems, the performance regulation of the fan installation of the main ventilation is carried out by changing the installation angle of the blades of the guide vane [8]. This method is based on the use of the phenomenon of swirling air flow in front of the impeller, being the simplest and does not require additional costs [9]. Despite the fact that, as a rule, this method is used with small ranges of changes in performance, it is optimal and is used in this work.

4. Ensuring the safe operation of automation devices

During preparation and work with the device, the requirements of the current Safety rules in coal mines, Rules for the technical operation of coal mines, Rules for the technical operation of electrical installations of consumers and Rules of safety in the operation of electrical installations of consumers,", standard labor protection instructions for occupations, operational documents and other regulatory documents on occupational safety, operating in the field [15].

  1. Before commissioning the automation device, the service personnel must be acquainted with the rules of using the equipment.
  2. Do not disassemble, repair and adjust kompleustroystva elements, except as provided instruction manual.
  3. For installation and commissioning of automation devices, persons who have undergone special training and relevant qualifications and are allowed to work with the device are allowed.
  4. The operating personnel working with the device must be familiar with the device and the device operation rules set out in the operation manual, as well as with the mine accident prevention plan where the device is used.
  5. Sanitary and hygienic conditions in the place of installation of the LHC must comply with current regulations.

Conclusion

In the master's thesis, an analysis of the modes of operation of the main ventilation system with a fan is made. It was found that these objects often work with increased productivity and, consequently, with excessive energy consumption; In addition, unforeseen violations of the ventilation regime often lead to failures in the technological process of mining. Based on the analysis, a device was developed to automatically control the performance of the fan unit of the main ventilation of the shaft for automatic adjustment of the “operating point” of the fan in accordance with the changing aerodynamic conditions of the mine. The result of the implementation of the automation device is to increase the efficiency of the fan installation of the main ventilation of the mine, ensuring reliable, stable and economical ventilation of mine workings with a minimum deviation from the specified mode.

During the design, an algorithm was developed to describe the sequence of work, the basic automation equipment was selected, circuit solutions for the automation device were developed, requirements for trouble–free operation were put forward, and the economic feasibility of introducing an automatic control unit for the performance of the main ventilation unit at the mine was justified.

This master's work is not completed yet. Final completion: June 2019. The full text of the work and materials on the topic can be obtained from the author or his head after this date.

References

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