Abstract: An impact-resistant balanced hydro-cylinder with pressure relief and buffering protection comprises a cylinder body (11), a piston (13), a piston rod (14), and a first valve core (21) and a second valve core (51) slidable relative to the cylinder body (11). A closed first gas cavity (22) and a closed second gas cavity (52) are respectively formed between the two valve cores and inner walls of two opposite ends of the cylinder body (11). A closed first oil cavity (32) and a closed second oil cavity (42) are respectively formed between the two valve cores and two end faces of the piston (13). A through hole (33) for the first oil cavity and a through hole (43) for the second oil cavity are respectively provided in the positions on the cylinder body (11) corresponding to the first oil cavity (32) and the second oil cavity (42).

Abstract: The present disclosure relates to a hydraulic support with a quick response function for coal wall spalling, which includes a base, an upright post, a top beam, an extensible canopy, a face guard, and a vibration meter. The vibration meter is mounted on a hydraulic support, and detects a vibration signal of a coal wall in a non-contact mode. The face guard includes a primary face guard, a secondary face guard, and a tertiary face guard connected in sequence. One side, close to a coal wall, of the primary face guard is connected to a quick response device. The quick response device is in signal communication with the vibration meter. After receiving the vibration signal of the coal wall, the quick response device is abutted against the coal wall before the secondary face guard and the tertiary face guard fit the coal wall.

Abstract: An impact-resistant balanced hydro-cylinder with pressure relief and buffering protection comprises a cylinder body (11), a piston (13), a piston rod (14), and a first valve core (21) and a second valve core (51) slidable relative to the cylinder body (11). A closed first gas cavity (22) and a closed second gas cavity (52) are respectively formed between the two valve cores and inner walls of two opposite ends of the cylinder body (11). A closed first oil cavity (32) and a closed second oil cavity (42) are respectively formed between the two valve cores and two end faces of the piston (13). A through hole (33) for the first oil cavity and a through hole (43) for the second oil cavity are respectively provided in the positions on the cylinder body (11) corresponding to the first oil cavity (32) and the second oil cavity (42).

Abstract: A large-capacity bag-type constant-pressure accumulator comprises a shell and a bag placed in the shell, as well as a variable area piston, a floating piston, a piston, and a flange. On the piston rod of the variable area piston is mounted the floating piston, while at the bottom of the variable area piston rod is connected the piston. Additionally, through holes are provided on the central axes of the variable area piston and the piston; such holes are connected to the bag through an inflation valve and connected with a cover plate at the bottom. On the piston are arranged the check valves I and check valves II. The flange is connected to the inner wall of the shell bottom.

Abstract: A portable intrinsically-safe device for acquiring vibration signal comprises a vibration signal acquisition unit, a signal processing unit, a signal storage unit and an intrinsically-safe power source, wherein the vibration signal acquisition unit is connected to the signal storage unit through the signal processing unit; the intrinsically-safe power source supplies power for all the units; the signal processing unit and the signal storage unit are integrally packaged in an intrinsically safe manner. The device solves the vibration signal acquisition from a large portable electromechanical equipment, providing a powerful data information for equipment status monitoring and failure analysis. Particularly, intrinsically safe design satisfies the test requirements when the portable equipment is under a complex and harsh environment of a coal mine well. The device is easy to mount, low in power consumption, easy to control, flexible to use and wide in range of application.