Method of making constant flow irrigation tape

A method of making a constant-flow drip irrigation hose of the type having an elongate primary water flow path extending therethrough, and a secondary flow path extending from said primary flow path to open outwardly of said hose, said method comprising the steps of:

• providing an elongate flexible resilient strip having opposite longitudinal marginal edges from which to form an elongate hose body with a boundary wall for said irrigation hose;
• wrapping said strip on itself with a first longitudinal marginal edge portion and an opposite second longitudinal marginal edge portion of said strip overlapping each other;
• sealingly securing said elongate wrapped strip to itself at circumferentially spaced locations adjacent to said longitudinal marginal edges to form said strip into an elongate hose body having a boundary wall;
• using said hose body to define an elongate primary water flow path which is bounded by said boundary wall and which extends through said irrigation hose;
• employing the overlapping of said marginal edge portions of said strip to define a secondary water flow path disposed radially between said overlapped first and second marginal edge portions and circumferentially between said first and second marginal edges;
• providing an inlet port communicating water from said primary flow path to said secondary flow path, and providing an outlet port spaced along the length of said hose from said inlet port for communicating water from said secondary flow path outwardly of said hose;
• forming one of said marginal edge portions to define a longitudinally-extending tortuous constantly-open flow channel opening toward the other of said marginal edge portions and defining a first part of said secondary flow path extending between said inlet port and said outlet port;
• providing one of said first marginal edge portion and said second marginal edge portion with a longitudinally-extending groove of dimension wider than said tortuous channel and narrower than the circumferential extent of said secondary flow path;
• spacing said marginal edge portions radially apart to provide a variable-area part of said secondary flow path extending longitudinally between said inlet port and said outlet port;
• using said longitudinally extending groove to define a third variable-area part of said secondary flow path;
• exposing an inner one of said marginal edge portions to water pressure within said primary flow path;
• flexing said inner one of said marginal edge portions to respectively increase and decrease the area of said variable-area second part of said secondary flow path in response to respective decreasing or increasing water pressures within said hoses;
• and
• using said inner marginal edge portion to further deflect toward the outer one of said marginal edge portions in response to water pressure within said hose to constrict said variable-area third part of said secondary flow path after said variable-area second part of said secondary flow path has been substantially closed.