Abstract: A temperature insensitive, low cost, pressure regulating and remotely flushable emitter for drip irrigation systems comprises a nodal body insertable into the wall of a pipe and having an end face aperture in which a deflectable resilient element responds to interior water pressure changes. The resilient element is deflectable normally to the plane of the end face, and provides at least one edge surface in facing, shearing relation to the end face aperture wall. In a first mode, one or more slit apertures decrease in area in response to increases in interior water pressure within a nominal operating range. When the pressure is raised further, however, the resilient element is deflected across the end face aperture wall, to define at least one slit aperture providing a low volume but high velocity flow which creates a flushing or cleaning action.

Abstract: A low cost valve, such as an emitter for controlling the flow from an aperture in a drip irrigation pipe, operates dynamically to maintain flow substantially constant across a wide range of pressures. A cylindrical valve seat mounted within the pipe aperture receives a valve member having a coaxial stem portion that extends through the valve seat to couple an external cap member. The interior end of the valve member comprises a diverging cone defined by integral and circumferentially separated leaf elements that engage a bearing surface of the valve seat at a root circumference when unstressed. Increasing water pressure within the pipe acts against the interior of the cone surface, distorting the leaf elements inwardly a proportional amount and shifting the valve member relative to the bearing surface through a selected limited operating range.