Abstract: There is provided a hydraulic pump startup control device in a hydraulic system, which avoids an overloaded state at startup to enable low-temperature, fast startup and maintaining of the temperature with low-cost means in order to improve low-temperature startability. A bypass path 19 is placed in parallel with a hydraulic main line from a hydraulic tank, and the downstream of the bypass path is made merged with the hydraulic main line. A bypass valve 3 that opens or closes the bypass path is provided in the bypass path, and a pressure sensor is provided in the inlet of a hydraulic unit in the hydraulic main line. Further, a control device 10 to which a pressure detection value in the hydraulic main line is input from the pressure sensor to open the bypass valve based on the pressure detection value upon startup of the hydraulic unit.

Abstract: This invention includes a container 2, a rotation shaft 4 penetrating through the container 2, a seal portion 5 provided between the container 2 at a fixed-side and the rotation shaft 4 at a rotation-side, and a foreign material entry prevention unit 7 (a pump 25, a high-pressure water providing line 26, an outlet 27) for preventing fine slag, i.e., foreign material in slag hopper water 8 (muddy water), from entering into the seal portion 5. As a result, with this invention, high-pressure water flowing out of the outlet 27 can prevent fine slag from entering into the seal portion 5.

Abstract: There is provided a hydraulic pump startup control device in a hydraulic system, which avoids an overloaded state at startup to enable low-temperature, fast startup and maintaining of the temperature with low-cost means in order to improve low-temperature startability. A bypass path 19 is placed in parallel with a hydraulic main line from a hydraulic tank, and the downstream of the bypass path is made merged with the hydraulic main line. A bypass valve 3 that opens or closes the bypass path is provided in the bypass path, and a pressure sensor is provided in the inlet of a hydraulic unit in the hydraulic main line. Further, a control device 10 to which a pressure detection value in the hydraulic main line is input from the pressure sensor to open the bypass valve based on the pressure detection value upon startup of the hydraulic unit.