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The hydraulic support is the supporting equipment of the fully mechanized work, and its main function is to support the roof of the stope, maintain the safe working space, and carry out the working face mining equipment. Hydraulic support not only in the process of work reliably and supporting roof should be able to move forward along with the mining working face advancing, for hydraulic support must have a rise, fall, pushing, four basic actions, these actions by the supply of emulsion pump high pressure liquid, through a variety of valve control columns, jack is adjustable.

1. Lifting and lifting of the bracket

The rise and fall of hydraulic support is done by the rise and fall of pillar, column is supported in the top beam and the rise and fall of hydraulic support is done by the rise and fall of pillar, column is bearing between the cap and the base of the hydraulic cylinder, its movement through the three valve (control valve, hydraulic controlled check valve and relief valve) between the base of the hydraulic cylinder, its movement through the three valve (control valve, hydraulic controlled check valve and relief valve) control.

There are three stages in the lifting and lifting of the bracket: the stage of initial support, bearing and unloading.

The loading stage can be divided into: the process of increasing resistance and the phase of constant resistance.

A preliminary stage

Move the control valve handle made by emulsion pump for high pressure liquid into the inferior vena (piston chamber), the post column under the action of high pressure liquid rises drive the top beam and support roof, after the upper roof beam exposed roof, column inferior vena work pressure to pump station pressure, emulsion pump station automatic unloading, hydraulic controlled check valve closed, so that the columns of the inferior vena fluids are closed, this is setting stage of the hydraulic support, the bracket of roof support call early supporting force.

B bearing stage of carrying stage

The load stage is divided into: the phase of increasing resistance and the phase of constant resistance

Increases the resistance stage: at the beginning last stage is completed, as the roof sinks or unloading due to coal and neighboring stents moved forward, the influence of column inferior vena sealed liquid pressure rising, the effect of the stents resistance of unloading forward, this kind of support resistance increasing calls to add resistance. At this point until the lower cavity pressure reaches the relief pressure of the relief valve. The rising state is called an increasing resistance. At this point until the lower cavity pressure reaches the relief pressure of the relief valve.

Constant resistance stage: with the roof sinking, the pressure continues to increase, pillar inferior vena fluid pressure continues to rise, to the relief valve of unloading pressure (i.e., the relief valve setting pressure), the relief valve opens, high pressure fluid through the relief valve overflows, pillar and immediately fell, until the roof pressure distribution to the bracket, that face our support to reduce pressure, the pillar of the inferior vena pressure less than the action pressure of safety valve, safety valve and closed, stop the overflow, the overflow relief valve opening and closing is the process of constant resistance condition of the hydraulic support, over and over again in a state of constant resistance of hydraulic support, will continue to sink due to the overflow of the relief valve, hydraulic support in a state of constant resistance bearing stage pressure support, will continue to sink due to the overflow of the relief valve, hydraulic support on loading phase column and the support of the maximum load carried by the known as the maximum working resistance.

When the working face roof pressure is small, after the initial support to supporting force, at the side of the coal or brackets down under the influence of mobile, working resistance, although rising rapidly, but not reached the rated working resistance of support, as the relatively stable stage, the support working resistance continues to slowly rising, in this case, the stent could reach the rated working resistance, may also move to unloading frame until reach the rated working resistance. When the working resistance of the hydraulic support is lower than the rated working resistance, the resistance is increased to ensure the effective support of the bracket to the roof. Reaches the rated working resistance, with constant resistance, by limiting the maximum support of stents, exceed the rated working resistance is yielding, make stents under constant resistance with roof convergence, shrinkage.

The resistance is mainly guaranteed by liquid control one-way valve and strut.

Constant resistance and compressibility are realized by the safety valve.

Therefore, the liquid control one-way valve and safety valve are the key components to ensure the performance of the stents.

C. unloading phase

With reverse move control valve handle, as in the frame for the liquid state, high pressure fluid cavity from the high pressure pipeline into the column, open the hydraulic controlled check valve at the same time, the pillar of the inferior vena liquid by the hydraulic controlled check valve, control valve to return to the liquid pipeline, then stent unloading, unloading before moving frame. Back to the valve and control valve, the stents fall off and unload before moving.

2. Passage of scaffolds

The thrust of the hydraulic support consists of two actions: one is to push the work conveyor to the coal wall (push), and the other is to move the hydraulic support forward. The top coal stents are added to add a rear conveyor to the rear conveyor. Rear conveyor belt of rear conveyor.

3. Adjust frame, anti-pouring, anti-slip, side protection, protection, adjusting frame, balancing jacks and other supporting actions.