Drip irrigation hose and method for its manufacture

• US 5,522,551 A
• Filed: 07/19/1994
• Issued: 06/04/1996
• Est. Priority Date: 05/26/1993
• Status: Expired due to Term

• Current Assignee: T-Systems International Incorporated (Deere & Company)
• Original Assignee: T-Systems International Incorporated (Deere & Company)
• Inventors: DeFrank, Michael, Teegardin, David L., Marchetti, David
• Primary Examiner(s): Kashnikow, Andres
• Application Number:
  US08/279,813
• Time in Patent Office: 686 Days
• Field of Search: 239/107, 239/533.1, 239/533.13, 239/533.15, 239/542, 239/562, 239/566, 239/568, 239/602, 239/DIG. 12, 156/201, 156/202, 156/203, 156/252, 156/465, 156/466, 156/513
• US Class Current: 239/542
• CPC Class Codes: A01G 25/02 Watering arrangements located above the soil which make use of perforated pipe-lines or pipe-lines with dispensing fittings, e.g. for drip irrigation
• CPC Class Codes: B29C 2793/0036 Slitting
• CPC Class Codes: B29C 53/52 using external forming surfaces, e.g. sleeves
• CPC Class Codes: B29D 23/00 Producing tubular articles B29D24/00 takes precedence
• CPC Class Codes: B29L 2023/005 Hoses, i.e. flexible
• CPC Class Codes: B29L 2031/70 Agricultural usage or equipment
• CPC Class Codes: F16L 11/12 with arrangements for particular purposes, e.g. specially profiled, with protecting layer, heated, electrically conducting F16L11/11 takes precedence
• CPC Class Codes: Y02A 40/22 Improving land use; Improving water use or availability; Controlling erosion
• CPC Class Codes: Y10T 156/1013 and edge-joining of one piece blank to form tube
• CPC Class Codes: Y10T 156/1056 Perforating lamina
• CPC Class Codes: Y10T 156/1304 Means making hole or aperture in part to be laminated

Abstract

A drip irrigation hose of the continuous emitter type in which the outlets from the regulating passage each comprise a single longitudinal slit. By controlling the length of the slits and the flexibility of the film, water drips from the outlets when the hose is pressurized without clogging when the hose is depressurized. The slits are sufficiently long and the film is sufficiently flexible so the water drips from the outlets when the hose is pressurized. The slits are sufficiently short and the film is sufficiently rigid so the outlets close completely when the hose is depressurized. An outlet forming wheel has a knife blade on its periphery. A backing wheel engages the outlet forming wheel to establish a first nip therebetween. The backing wheel has on its periphery a circumferential slot into which the knife blade fits at the first nip. A rib forming wheel has around its periphery impressions that define a desired track pattern for the ribs. The outlet forming wheel and the rib forming wheel are mounted on a common shaft to operate in synchronism. A continuous strip of plastic film is directed in a path that reverses direction four times to accommodate these wheels.

Claims

1. A drip irrigation hose comprising:

an elongated flexible strip of plastic film bent along its length to form a lapped longitudinal seam between opposing longitudinal margins of the film;

first and second longitudinally extending transverse ribs in a spaced apart relationship interconnecting the opposing margins along their length to seal the overlapping longitudinal seam, thereby forming a flow regulating passage defined by the ribs and a water supply passage defined at least in part by the remainder of the strip;

a plurality of longitudinally spaced inlet ports to the flow regulating passage from the water supply passage;

a plurality of longitudinally spaced outlet ports from the flow regulating passage displaced from the respective inlet ports to provide a substantial path length from each inlet port to a respective outlet port,

each of the outlet ports comprising a single longitudinal slit in the strip, the slit being sufficiently long and the strip being sufficiently flexible so the water drips from the outlet port when the hose is pressurized, the slit being sufficiently short and the strip being sufficiently rigid so the slit closes completely when the hose is depressurized.

2. The hose of claim 1, in which the inlet ports are also slits.

3. Apparatus for making drip irrigation hose comprising:

a first inlet or outlet port forming wheel having a knife blade on its periphery;

a second backing wheel engaging the outlet forming wheel to establish a first nip therebetween, the backing wheel having on its periphery a circumferential slot into which the knife blade fits at the first nip;

a third rib forming wheel having around its periphery impressions that define a desired track pattern;

means for establishing with the third wheel a second nip in which the desired track pattern is formed;

a common shaft on which the first and third wheels are mounted to operate in synchronism;

first guiding means for wrapping a continuous strip of plastic film around the second wheel to reverse direction and pass into the first nip;

second guiding means for reversing direction of the film leaving the first nip to transport the film toward the first wheel;

third guiding means for wrapping the film around a portion of periphery of the first wheel spaced laterally from the knife blade to reverse direction;

fourth guiding means for reversing direction of the film to transport the film toward the third wheel;

means for depositing a bead of molten plastic on the film between the fourth guiding means and the third wheel;

fifth guiding means for transporting the film into the second nip to form the desired track in the molten plastic; and

means for finishing the hose after the strip of film leaves the third wheel.

4. A method for making drip irrigation hose with a first port forming wheel having a knife blade on its periphery, a second backing wheel engaging the port forming wheel to establish a first nip therebetween, the backing wheel having on its periphery a circumferential slot into which the knife blade fits at the first nip, and a third rib forming wheel having around its periphery impressions that define a desired track pattern, the method comprising the steps of:

establishing with the third wheel a nip in which the desired track pattern is formed;

mounting the first and third wheels on a common shaft to operate in synchronism;

directing a continuous strip of plastic film in the following path in the order recited;

wrapping the film around the second wheel to reverse direction and pass into the first nip, thereby forming outlet slits;

reversing direction of the film leaving the first nip to transport the film toward the first wheel;

wrapping the film around a portion of periphery of the first wheel spaced laterally from the knife blade to reverse direction;

reversing direction of the film to transport the film toward the third wheel;

transporting the film under an extruder to deposit a bead of molten plastic on the film before the third wheel; and

transporting the film into the second nip to form the desired track in the molten plastic; and

finishing the hose after the strip of film leaves the third wheel.