| 摘要 |
<p>The invention relates to a device for increasing the degree of dynamic adaptability of the powered props in coal mine working, and which comprises a control unit (A) and a processing unit (B), namely two auxiliary valves, an inlet valve (12) and a direction valve (11). The device ensures the working in geomechanical conditions wherein the mine stress field appears as fall of country, with high loading rate and a force of impact of more than 10^4 joules. By using said device, the hydraulic props are protected against the excessive rise of the liquid pressure in the chamber of the cylinder prop eliminating the possibility of mechanical damages, human and technical accidents. The device works in quasi-statistical conditions, as a common protection valve, or in dynamic conditions when a pusher (4) ensures the opening of the pilot valve (5) at low pressure values, but at high variation speeds thereof so that the piloted valve receives the stress impact as a direction valve with a slack spring. When the stress in the hydraulic props (1) decreases, the spring of the pilot valve (5) closes the return and when the cavity at the back of the piloted valve is filled with fluid, the pressure in the prop causes the piloted valve to close. In dynamic conditions, the pressure impact controls the pilot valve opening, before the pressure increase at the back of the piloted valve. The invention may be used for equipping the hydraulic props provided in the sustaining sections, which are to work in the working whose roof is characterised by fall of country.</p> |
