Continuous tube emitter

Abstract

A continuous tube emitter comprises an elongated flexible plastic tube with internal pressure-responsive flow control units to control the flow rate of irrigation water through outlet openings in the tube. The flexible plastic tube is formed from an elongated thin film web having one or more relatively thicker valve members on one side thereof defining a plurality of valve faces, wherein each valve face includes at least one shallow drip emission groove leading into a valve reservoir of wider cross section and communicating respectively with the outlet openings cut through the web. One longitudinal margin of the web is trimmed to form laterally projecting flaps at longitudinal positions generally corresponding with the valve faces. The web is then rolled upon itself about a longitudinal axis and longitudinally seamed to form the continuous tube emitter with the flaps each internally overlying the valve reservoir and a portion of the drip emission groove of a respective valve face to define one of the flow control units. In a preferred form, the flaps include structure for maintaining the flaps in close overlying relation with the valve faces. In use, water pressure within the tube forces the flaps into engagement with the aligned valve faces to restrict and control the rate of water flow through the outlet openings.