| 摘要 |
A subsurface emitter 10 includes a piston valve 20 both restricting water from draining from the system, and blocking the entry of roots and soil into the emitter body 11. A nozzle 12 is present at one or both ends of a vertical tube. The piston 20 is held in a normally closed position by a spring 22 in the absence of water pressure, covering ports 14 in the nozzle 12. When sufficient water pressure in provided, the spring 22 is compressed and the nozzle 12 uncovers the ports 14 providing a subsurface spray 15 of water. The spray of water is sufficient to clear mineral deposits which otherwise may accumulate and block the ports 14. |
