论文部分内容阅读
手持式旋转钻机广泛应用予煤矿和油页岩矿。其每年的钻孔深度可达6000万米。钻孔过程的劳动不仅繁重,而且伴随产生大量的微粒粉尘。目前,煤矿使用 PM—43和 py—4M 型钻头,这些钻头的技术经济指标不高,粉尘排放方式有缺陷。50微米以下粒度的粉尘排放量占全部钻孔体积的15%。其主要原因在于:PM—43型钻头口径角大(70～75°),高度小,导致在钻碎过程中对煤的冲击点的破坏,且无剪切作用。py—4M 钻头尖端的外缘锥度小,因而炮眼侧壁的煤受到破坏,
Hand-held rotary drilling rig is widely used in coal mines and oil shale mines. Its annual drilling depth of up to 60 million meters. The drilling process is not only laborious but also produces large amounts of particulate dust. At present, PM-43 and py-4M drill bits are used in coal mines. These drill bits have low technical and economic indicators and have a defective dust emission pattern. Dust emissions below 50 microns account for 15% of the total borehole volume. The main reason is that the diameter of the PM-43 drill is large (70-75 °) and its height is small, which leads to the destruction of the impact point of coal during the drilling process without any shearing action. Py-4M drill tip taper edge of the small, so the destruction of the coal side walls of the hole,