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Abstract

Содержание

Introduction

Mine hoist is the most important process in technological chain of coal production. Being a horse-drawn transport,  a hoist belongs to discrete mode of  transport when the delivery of coal when the delivery of coal to a certain point is put into practice by limited portions of mass [2]. Overloading of this transport leads to reducing of a term of rope service and the whole unit. Shortfan also reduces the efficiency of the transport. Therefore, it is impossible to overestimate the importance of  automation of the object for mining industry. 

1. Actuality of the topic

Modern means of automation can improve the reliability and durability of the equipment, increase productivity, reduce energy consumption, give a diagram to work out optimum speed without emergency inrush current and torque drive, having destructive forces on the lifting equipment, ensure complete control over 

all the necessary parameters that influence the operational status of the unit and appropriate responses to their changes.

From this point of view the most effective are multi-circuit systems with subordinate adjustment of parameters. These systems foresee varouus return links giving opportunities to observe anomalous changes of controlling  parameters and control in accordance with getting information. Return links foresee presence of devices transforming a controlling parameter into a signal, which is used in control, a return link, in this case, will be a speed and skip quickening, as well as the time of moving cycle, a rope strain and a quantity of consuming energy.

A control system of mine hoisting plant weight and average speed of the cycle, which determine the overall cycle time, is one of the main parameters. To do this, it must be reached all of the following requirements: 

analysis of the acceptable parameters of regulation of high-speed mine hoisting unit parameters, motion corresponding to the requirements of the Safety Rules [1]; 

2. Goal and tasks of the research

The aim is to increase the efficiency of the lifting process by developing a system of adaptive management productivity of mine hoisting plant. The main objectives of the research are:

In the frames of the master's work it's planned: 

For the experimental evaluation of the theoretical results and further research foundation, as the practical results of the management I plan the engineering of device,which will allow speed control of mine hoisting plant as a part of the automated mine lifting process control system (PCS).

Requirements for the automation system recovery for further PCS: 

mine hoist

Figure 1 – Mine hoist

1 – Skip, 2 – Schieber tank, 3 – Hopper, 4 – Receiving hopper, 5 – Schieber hopper,

6 – Lifting pulleys, 7 – Gear, 8 – hoist drum , 9 – hoist drive engine

Research object: Mine hoist

Research subject: mine hoisting plant control methods in different speed modes.

3. Identification of method for mine hoist productivity control

Modern automation tools allow machines to increase unitt productivity, optimize the speed chart, as well as reduce the magnitude of the average consumption of electrical energy per cycle of motion of lifting the vessel through the fidelity of defined parameters. However, these solutions do not provide the productivity management of mine hoist, taking into account requirements of daily changes of electric power consumption, the tension of the rope hoist, and also depending on the size of the average cargo traffic on the loading site. Since, according to safety rules [1], the permissible speed for cage hoists is limited to  12 mps, and to skip – is determined by project indicators of expediency of efficient control implementing of a hoist limit during 24 hours. The daily productivity of the lift installation is determined from the expression.

[2]:
the daily productivity,

where  Ac – mine hoist daily productivity, tons;

Qп  –  hoisting capacity, tons;

Tc – mine hoist daily work duration, sec

Tц – lifting cycle duration, sec;

Tп – technological pause duration, sec.

Analysis of this expression shows that mine hoist productivity depends on cycle duration is shown as:

cycle duration,

where Н – depth of mining, m; 

vc – average skip velocity per cycle, m/sec

The average value of expendable electric power is given by:

The average value of expendable electric power,

where vр – hoisting plant contant motion velocity , m/sec; 

η – mining hoist general efficiency 

Fi – dynamic forces acting on the vessel to lift specified range chart speeds, KN

t3, t5 – duration of periods of acceleration and deceleration respectively.

Mine hoist work

Figure 2 – Mine hoist work

(animation: 17 frames, 6 cycles of repeating, 45 kilobytes)

To ensure safe lifting operation is necessary to monitor the maximum tensile hoisting rope force is given by::

tensile hoisting rope force,

where 

Fн – maximum tensile hoisting rope force, KN; 

mпр – reduced to the axis of the lifting machines mine hoist weight;

a1 – the main lifting vessel acceleration

Using these formulas, we obtained a comparative table showing change parameters effect of the average daily productivity rate and recovery, and and consumption values ​​drive motor power depending on the parameters of the speed limit (Table 1).

Table 1 – speed modes variables dependence

Mode 1 – Changing the uniform velocity  (a1, a2=0,8)
vр
 8,5 9 9,5 10 10,5 11 11,5 12
vcр
 7,16 7,49 7,8 8,1 8,39 8,67 8,93 9,19
Ac
 4830 5040 5250 5460 5640 5850 6030 6180
P
 637,44 641,23 645,24 649,46 653,89 658,51 663,33 668,34
Fн
 487,8 487,8 487,8 487,8 487,8 487,8 487,8 487,8
Mode 2 – acceleration and slowdown change a1 a2 (vp= 10)
a1, a2 0,6 0,7 0,8 0,9 1 1,1 1,2 1,3
vcp
 7,89 8,01 8,1 8,17 8,23 8,28 8,32 8,35
Ac
 5310 5400 5460 5520 5550 5580 5610 5640
P
 636,3 640,5 645,2 650,5 656,3 662,6 669,5 676,8
Fн
 449,6 468,7 487,8 506,9 526 545,1 564,2 583,3
Mode 3 – slowdown change  a2 (vp=10, a1=0,8)
a2 0,6 0,7 0,8 0,9 1 1,1 1,2 1,3
vcp
 7,16 7,49 7,8 8,1 8,39 8,67 8,93 9,19
Ac
 5400 5430 5460 5490 5490 5520 5520 5460
P
 632,9 641,4 649,5 657,2 664,7 672,2 679,6 690,2
Fн
 487,8 487,8 487,8 487,8 487,8 487,8 487,8 487,8

Analysis of Table 1 shows that in mode 2 when the quickening of movement increases linearly, the dynamic force of the tension  increases greatly. The quantity of electric power consumption, and in modes 1 and 3, the tensile force of the rope remains constant

Conclusion

Thus, the most efficient operating mode of the mine hoist performance is themode of change of velocity of constant motion of lifting unit, which does not contradict with the requirements of the Safety Rules [1]. However, the development of automatic control systems and modes of the brake system will improve the efficiency of lifting.

This master's work is not completed yet. Final completion: December 2011. The full text of the work and materials on the topic can be obtained from the author or his head after this date.

References

  1. НПАОП 10.0–1.01–10 Правила Безпеки у вугільних шахтах.
  2. Бежок В.Р. Шахтный подъем: [научно-производственное издание] под общ. ред. Б.А. Грядущиего, В.А. Корсуна. / В.Р. Бежок – Донецк: ООО Юго-Восток, Лтд, 2007. – 624 с.