Coal seam liq. injection tube - has resilient cap over impact strip following sideways discharging jet holes

A tube for injecting liquids into a coal seam has a textile reinforced wall (1) connected to a pump with its discharge end compressed to a restriction (4) immediately preceding the sideway aligned discharge holes (7). The restriction (4) is caused by a serrated band (5) attached to a U shaped metal strap (6). This strap forms an impact surface for the liquid pumped down the tube. It is enclosed inside a resilient cap (16) of rubber or plastics material, which also extends around the serrated band (5). The diameter of the cap is the same or less than the diameter of the tube (1).