Abstract

A generally cylindrical or partially cylindrical body is intimately received in an irrigation pipe and has an outer surface in physical contact with an inner surface of the pipe. A flow-limiting labyrinth is formed by the outer surface of the body in combination with the pipe inner surface. A valve chamber is formed in the body and has four pairs of inlets and outlets forming an inlet retention valve and three labyrinth bypass valves. The first inlet is in fluid communication with the pipe interior and the first outlet is in fluid communication with the labyrinth inlet end. The inlet retention valve includes a first valve seat that surrounds the first inlet. Each bypass valve is connected between a respective section of the labyrinth and an external pipe outlet. The retention valve prevents flow through the emitter when pipe internal water pressure is below a minimum pressure, and the bypass valves close progressively to increase the effective and actual length of the labyrinth for increasing water pressure above the minimum pressure.

Other References

• Netafim Irrigation Equipment & Drip Systems promotional leaflet, "Compensating Non Leakage (C.N.L.) Dripper", 12-92CNL1-1
• IRRI Gazette (European Irrigation Magazine), No. 16, 1993 edition, p. 9. ISSN 1153-0561 published in Israe