| 摘要 |
<p>The injection head, mounted on the end of a string of rods or pipes delivering a liquid under pressure, comprises a housing (32) with its upper end (40) connected to the rods or pipes, an outer wall (34) and an inner nozzle (50). A curved duct (54) inside the housing is connected at one end to the lower end of the liquid feed pipe (48) and at the other tangentially to the nozzle. The curved portion of the duct is of continuously variable radius and has a regularly reducing cross-section towards the nozzle outlet for at least half its length.</p> |
