| 摘要 |
A blast gun in which blast material e.g. blasting sand is passed through an injection pipe 2 into a blast nozzle 1, blast air is led into the blast nozzle through an air supply gap 3 between the injector pipe 2 and the blast nozzle 1, and a valve mechanism 14 is adapted to control the blast air supply to the blast nozzle 1. In order to keep the air supply gap 3 unobstructed so that this gap will not be clogged by material supplied to the blast gun when the air supply ceases at least one air passage 26 is provided which, when the valve mechanism 14 is closed, allows blast air to pass to the air supply gap 3 for the purpose of keeping the gap clean. <IMAGE> |
