Ground jet system of suspension and air feed fits suspension outlets in end of nozzle support at angle to drillrod so suspension feeds via ball valve to outlets as nozzle support rotates.

摘要

A nozzle support (20) at the end of the drillrod (5) contains the air feed (12) and suspension pipe (10) outlets (22,24) at an angle to the drillrod. The suspension pipe and air feed steadily curve round to the mouth outlets (22,24) and a ball valve (30) between suspension pipe (10) and in-mouth pipe part comprises a ball (3) opening opening up towards the outlets against its loadspring (32) when the suspension is fed down the pipe (10). The nozzle support presents a pear-shaped housing or a double cone to take part of the suspension pipe (10) and air feed (12). The mouth outlets (22,24) can be fitted with exchangeable nozzles, differing in section but equal in pitch.