Grouting pit-props in rock tunnels and mines - with device using compressed air cylinders to inject grouting into holes

摘要

Pneumatic device for injecting grouting contg. a hydraulic binder into a drilled hole of small dia., the novelty being that it consists of two pistons mounted on the ends of a common piston-rod in two coaxial cylinders, one being used to draw the grouting from a container and the other being used to force it into the drilled hole, i.e. one piston-cylinder unit applies suction and the other then applies the injection pressure, the two assemblies being alternately supplied with compressed air from the same source. Alternatively, the piston used to obtain suction may also be used to apply the pressure, and the speed of the pistons is pref. variable. The device is used e.g. in grouting bars in tunnels made in solid rock or lodes, e.g. for pit-props.