| 摘要 |
PURPOSE:To allow powerful injection of water even in water for improved cleaning operation or others by the water jet by injecting water from the top end of an inner pipe and enclosing the water jet by a layer of air injected from an injection port defined between the inner pipe and an outer pipe. CONSTITUTION:An underwater jet device 20 has a double structure composed of an inner pipe 1 and an outer pipe 2. The inner pipe 1 is connected to a pipe 4 provided with a valve 3, and pressurized water W supplied through the pipe 4 into the inner pipe 1 is injected from the top end 1a thereof. An annular passage 7 is defined between the inner pipe 1 and the outer pipe 2, and the annular passage 7 is connected to a pipe 6 provided with a valve 5. High pressure air A supplied through the pipe 6 into the passage 7 is injected from an injection port 8 which is an outlet of the passage 7. As the result, the high pressure air A encloses the pressurized water W. Consequently, water jet can be injected efficiently even in water, allowing efficient cleaning of structures and excavation in water. |
