| 摘要 |
The invention relates to a tool for size-reducing coke, comprising a housing which, in the operating state, is fastened to a drill rod and in which at least one cutting tip for cutting and one drilling tip for drilling coke by means of a water jet are arranged, and a switchable valve device, arranged in a through-flow channel, for optionally supplying the water to flow channels in a flow body for the paths towards the cutting and drilling tips, and a switching device for switching the valve device, said switching device being manually or water pressure-controlled at a switching pressure of the water. The switching device comprises a distributor element which is rotatably mounted upstream of the flow body and which comprises a valve body for closing at least one opening of the flow channels, the flow path of the water towards the drill tip or the flow path towards the cutting tip being released or blocked depending on the angular position of the distributor device relative to the flow body. In order to facilitate the rotational movement of the distributor device, the valve body comprises means for balancing the pressure in the flow channel downstream of the valve body to a switching pressure like in the through-flow channel. |
