RU2553619C1 - Protection device of mining hoisting units against rope slippage - Google Patents

Abstract

FIELD: mining operations.

SUBSTANCE: protection device of mining hoisting units against rope slippage comprises a measuring unit (1), a unit (2) of indication of the normal mode of the mechanism operation, a unit (3) of controlling the slippage of the part of steady speed, a unit (4) of emergency mode registering, a unit (5) of emergency shutdown, the first unit (6) of delay, the second unit (7) of delay, a unit (8) of controlling slippage on the part of acceleration.

EFFECT: increase in operation rate and prevention of emergency situations at early stages in order to minimise the consequences of an accident.

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Description

The invention relates to the field of mine hoisting machines, in particular to devices for protecting hoisting installations from slipping the rope along the leading friction pulleys (multi-rope and single-rope).

Known for the clamping device of the ropes of the driving pulley of the lifting machine, consisting of an endless rubber band, drums with tension weights and guides that press the leading ropes to the lining of the friction pulleys, while increasing the friction force between the ropes and the lining, as well as the angle of the pulley girth around the ropes [A. from. No. 506566].

The specified device has the following disadvantages.

The rubber cable will press the rope to the lining only if it is above the lining, so frequent lining replacement will be required to maintain the device in working condition. To create the necessary pressure of the tape, a significant load is required to be suspended.

The closest solution to the proposed device in terms of technical nature and the achieved result is a device for protecting hoisting installations against rope slipping, which is a rope braking unit consisting of fixed bars with friction plates, a fixed stop with bevels, a moving wedging element with friction plates, and spring-hydraulic drive, linkage, telescopic rail, air line, intermediate relay, automatic quick operating switch and electro-pneumatic valve (see A.S. No. 737340). When the ropes slip over the friction pulley, the protection turns off the DC lifting motor by activating the automatic high-speed switch and applying a safety brake with the release of air from the safety brake cylinder using electro-pneumatic valves through the pipelines. The disadvantage of the control device is the low speed of the mechanical part. The response time of the device is 1.2 ... 1.5 s.

The result of low speed can be severe accidents, namely: the destruction and failure of the lining, the uncontrolled movement of vessels and the destruction of the reinforcement of the trunk, wire breakage and vessel fall.

The objective of the present invention is to improve performance and the prevention of emergencies in the early stages in order to minimize the consequences of the accident.

The solution to this problem is achieved by the fact that the device for protecting mine hoisting installations from slipping the rope contains an emergency shutdown unit, which includes an intermediate relay and an automatic high-speed circuit breaker that turns off the DC motor, further comprises a measuring unit based on a shunt connected to the winding circuit motor anchors, the output of which is connected to the inputs of the first and second delay units, the output of the first delay unit is connected to the input of the unit slip control in the acceleration section, the output of which is in turn connected to the input of the emergency shutdown unit of the mechanism, the output of the second delay unit is connected to the input of the slip control unit in the steady-state section, the output of which is connected to the input of the normal operation indication block, the output of which is in turn connected to the input of the emergency mode registration unit, the output of which is connected to the input of the emergency shutdown unit of the mechanism.

Figure 1 shows a schematic diagram of the claimed device for protecting mine hoisting installations from slipping rope; figure 2 - temporary operation diagrams of the blocks included in the device.

The device for protecting mine hoisting installations from slipping the rope (Fig. 1) comprises a measuring unit 1, a normal operation mode display unit 2, a slip control unit 3 at a steady-state speed section, an emergency mode registration unit 4, an emergency shutdown unit 5, a first delay unit 6, second delay unit 7, slippage control unit 8 in the acceleration section.

The measuring unit 1 is made on the basis of a current-measuring shunt, an operational amplifier and a diode bridge, an RC circuit designed to filter low frequencies. In the second delay unit 7 and the first delay unit 6, subtraction operations are implemented. The blocks are implemented on the basis of summing amplifiers and a sign-changing amplifier. Block 3 control slippage at the steady-state speed section includes two operational amplifiers, which serve to set the lower and upper current values using adjustable resistances; then the AND-NOT logical element is installed, followed by the diode isolation, which serves to indicate the event "value deviation". Next, a normal operation mode display unit 2 is installed based on transistors and an LED serving as an indication of the “operation” mode. The emergency mode recording unit 4, based on an operational amplifier shunted by an RC circuit to filter low frequencies, and an LED displaying the “Exceed Value” mode. The emergency shutdown unit 5 of the mechanism is made using transistors that control the relay coil, by means of which the automatic high-speed circuit breaker trips and the motor power is turned off. At the same time, the indication fixing the “accident” mode lights up. The slip control unit 8 in the acceleration section is based on the operational amplifier and adjustable resistance, which sets the value of the emergency value of the starting current at which the operational amplifier is triggered.

Figure 2 (a-d) shows: a - the angular velocity of rotation of the engine; b - armature current of a DC motor; c - the initial engine control signal having two states (“Start”, “Stop”); g - the output of the first block 6 delay; d - the output of the second block 7 delay.

The protection device of lifting installations from slipping rope works as follows.

At the time of starting the mechanism by means of a relay circuit from the measuring unit 1, an information signal is supplied to the first 6 and second 7 delay units. From the first delay unit 6, the signal is fed to the input of the slip control unit 8 in the acceleration section, and from the second delay unit 7 to the input of the slip control unit 3 in the steady-state section and then the input of the normal operation mode indication unit 2 is fed from the input to the input unit 4 registration emergency mode, the output signal of which comes to the input of block 5 emergency shutdown mechanism.

In block 8 of the slip control in the acceleration section, the following logical function is implemented:

where x (τ) is the output of the slip control unit 8 in the acceleration section, which has two levels of Off. and slave .;

Δ ₁ - the current value of the current in the acceleration section;

Δ ₂ - the value of the permissible current value in the acceleration section;

Δ ₃ - the value of the permissible deviation of the current value on the acceleration section.

If the difference in values (Δ ₁ -Δ ₂ ) is greater than the signal Δ ₃ , then the signal from the output of the slip control unit 8 in the acceleration section is fed to the input of the emergency shutdown unit 5 of the mechanism and the engine stops. Otherwise, the signal is not considered alarm and work continues.

At the input of the slip control unit 3, a signal from the second delay unit 7 is received at the steady-state speed section.

In block 3 slippage control on the steady-state speed section, the following logical function is implemented:

where y (τ) is the output signal of the slippage control unit in the steady-state section;

Δ ₄ is the value of the current value of the current in the steady-state section;

Δ is the value of the permissible current value in the steady-state section;

Δ ^* - the value of the tolerance value of the current at the time of steady speed.

If the difference in values (Δ-Δ ₄ ) is greater than Δ ^* , then the trip signal is received from the output of the emergency mode recording unit 4 to the input of the emergency shutdown unit 5. And in the case when the sum of the quantities (Δ-Δ ₄ ) is approximately equal to Δ ^* , the signal is considered non-emergency.

The inclusion of the system in the work (conditionally taken for a point in time τ = 0) occurs on a signal (Start), shown in figv. This signal is supplied from the local control panel by the operator of the lifting installation.

On figa shows a graph of the angular velocity of rotation of the engine. The entire work cycle consists of three sections:

1. The first section (τ = 0 ÷ τ ₁ ) is the acceleration section, where the engine moves with acceleration up to the moment τ _{1 of the} set nominal speed.

2. The second section is a section of movement with uniform speed.

3. The third section is the braking section (after the “Stop” command).

On figb shows a graph of the current values of the current values of the armature of a DC motor. Starting from the moment of starting (τ = 0), the engine accelerates to a steady speed, which lasts until time moment τ ₁ (5-8 s), after which the current stabilizes (as well as the rotation speed).

The output voltage U of the measuring unit 1 is proportional to the motor current

U = I _d * k _tsh * k _dt ,

where to _tsh - the shunt coefficient,

to _d.t. - coefficient of the current sensor circuit.

The graph of the output voltage U repeats the dynamics of the current values of the armature current I _d . The output of the measuring unit 1 is the information input of the device.

The information output of the measuring unit 1 is connected to the inputs of the first 6 and second 7 delay blocks.

2g, 2d show the output signals of the first delay unit 6 and the second delay unit 7.

The occurrence of an alarm is ensured by the successive operation of four blocks when monitoring slippage in the acceleration section and six blocks when monitoring slippage in the steady-state section. With the own response time of the analog blocks 5 * 10 ^-6 -10 ^{-5, the} total response time of the device will be determined mainly by the own response time of the emergency block 5 of the mechanism, amounting to 0.06-0.08 s and consisting of the response time of the relay (0, 04-0.05 s) and an automatic high-speed switch (20 ms).

Thus, the proposed device allows you to recognize the emergency situation of slipping rope in the early stages and will increase the response of the protection.

Claims (1)

A device for protecting mine hoisting installations from slipping a rope, comprising an emergency shutdown mechanism unit including an intermediate relay and a circuit breaker, an automatic high-speed disconnecting DC motor, characterized in that it further comprises a measuring unit made on the basis of a shunt included in the motor armature winding circuit, the output of which is connected to the inputs of the first and second delay units, the output of the first delay unit is connected to the input of the slip control unit in the acceleration section, the output of which is in turn connected to the input of the emergency shutdown unit of the mechanism, the output of the second delay unit is connected to the input of the slip control unit in the steady-state section, the output of which is connected to the input of the normal operation indication block, the output of which is in turn connected to the input of the emergency mode registration unit, the output of which is connected to the input of the emergency shutdown unit of the mechanism.

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