WO1990004464A1

WO1990004464A1 - Drip irrigation hose

Info

Publication number: WO1990004464A1
Application number: PCT/US1989/004731
Authority: WO
Inventors: Davies Allport
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-10-20
Filing date: 1989-10-20
Publication date: 1990-05-03
Anticipated expiration: 1991-04-20
Also published as: AU4517689A

Abstract

A drip irrigation hose formed of an elongated flat sheet of flexible water impervious material (10) having two longitudinally extending rib-like adhesive beads (16, 18) attached to a surface of the material (10) and positioned adjacent to one edge, the rib-like beads (16, 18) being die-formed to be precisely dimensioned and spaced from one another including precisely formed and spaced protrusions (21, 23) and pockets (25, 27). The sheet is turned over on itself forming a lapped longitudinal seam between opposing longitudinal margins (12, 14) of the sheet, and the rib-like adhesive beads (16, 18) are heat sealed, or otherwise attached to the other surface of the sheet (10) and extend between the opposing margings (12, 14) to form a flow regulating tube, with the protruded sides (21, 23) of the rib-like adhesive beads (16, 18) creating turbulence in the water flowing through the tube. The hose has filter-type inlets (22) longitudinally spaced along the flow regulating tube and outlets (24) from the tube longitudinally displaced from the respective inlets (22).

Description

DRIP IRRIGATION HOSE

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation in part of application Serial No. 07/147,814, filed on January 22, 1988.

BACKGROUND OF THE INVENTION

The invention relates to a drip irrigation hose of the general type described in U.S. Patent 4,247,051 which issued January 27, 1981 to the present inventor. The disclosure of this patent is incorporated fully herein by reference.

As described in the above patent, crop irrigation systems are well known and have been in agricultural use since early history. Current irrigation systems include field flooding, furrow flooding, and sprinkler. These prior art systems, however, tend to waste water, and they also tend to wash away nutrients, to compact the soil, and to aid in the growth of weeds. Also, these prior art systems for the most part require considerable labor in their operation, and they also tend to supply water to the irrigated crops at undesirable rates.

In order to reduce the problems inherent in the prior art systems discussed in the previous paragraph, various types of drip irrigation systems have come into widespread use. Unlike the systems described above which distribute excess water over wide areas, drip irrigation systems supply water at a slow, controlled rate to the root zone of the particular plants being irrigated. Typically, the foregoing is accomplished by providing a low volume water outlet at each plant which permits a limited dripping or flowing of water directly to the root zone of the particular plant. Since evaporation, runoff, overwatering, and watering beyond the root zone is eliminated, substantial water and nutrient savings are realized.

There are two major types of drip irrigation systems in present-day general use. One involves the use of fittings, or emitters, which are designed with restricting passages through which water must pass to an outlet. Such emitters, however, are relatively costly. Another type utilizes a continuous hose, such as disclosed in my Patent 4,247,051. This hose is formed by folding over the margins of an elongated plastic film to overlap and then connecting the overlapping margins by a pair of parallel longitudinal rib-like adhesive beads that together form a laminar flow regulating tube. Other hoses of this bead type construction that regulate the flow or a portion of the flow, via the flow path, have also not been configured to create turbulent flow.

-3- SUMMARY OF THE INVENTION

The drip irrigation hose of the present inventio has a flow regulating tube formed by the overlappin margins of an elongated sheet of plastic film and a pai of generally parallel longitudinal ribs that connect th margins as in the hose described in the above patent. A described in my patent 4,247,051, the ribs ar preferably, but not necessarily, formed as extrude adhesive beads. In the construction of the hose of th present invention, however, the interior walls of th ribs are shaped to provide a series of teeth-like weir along the flow regulating tube. These weirs introduc turbulence into the water flowing through the flo regulating tube. In the preferred embodiment, th extruded adhesive beads are molded to the desired shap and pattern by conventional rotary die wheels.

The resulting turbulent flow of water permits significantly larger flow regulating tube to be used. This is beneficial because certain types of material which tend to precipitate out and plug when the wate flowing through the regulating tube is in a lamina mode actually stay suspended in the turbulent water flo so as to pass through the flow regulating tube withou plugging or clogging it. In this way, the flo regulating tube of the present invention exhibits th characteristics of the more expensive emitters, referred to above, at a fraction of the cost.

Furthermore, with the turbulent water flow in th flow regulating tube of the drip irrigation hose of th present invention, greater uniformity is obtained whe the hose is used in undulating agricultural fields, a compared with the hose described in my Patent 4,247,051, which is laminar flow. This is because the flow rate o turbulent flow is less dependent on pressure tha laminar flow. Thus, as the pressure within the mai -4- chamber of the hose changes with elevation changes within the field, less variation in flow rate is experienced at the different elevations in the field.

In the case of laminar flow, the flow rate is directly proportional to the pressure change within the hose while with turbulent flow, the change is only half as much? thus, greater uniformity of flow results. In other words, if the change in elevation of the field effectively doubles the water pressure, the laminar flow rate doubles. In the case of the turbulent flow however, when the pressure doubles, the flow rate only increases by a factor of one and one half, rather than two.

Therefore, the flow variance is reduced by up to 50% in the hose of the present invention as compared with laminar flow hose and, accordingly, the uniformity coefficient for any particular agricultural field is improved by as much as a factor of 50%.

Another feature of the present invention is a root and soil diverter located adjacent to the outside edge of the film margin that forms the outlet and running parallel to that edge, but spaced apart from it. The diverter is attached to the outer adhesive rib like bead at each end of outlet opening, thus enclosing but not sealing the outlet. This diverter protects the outlet from intrusion by sand, soil and roots.

The outlet may also be configured so that the size and shape of the outlet and of the rib like beads are such that the end of a small water carrying extensio tube may be inserted into the inlet and down the space apart ribs to a point adjacent to the flow regulatin tube. The other end of the tube may be located near plant or in a pot to be irrigated.

Another feature of the invention is the formatio of the inlets to the flow regulating tube as a series o interruptions in the inner rib like bead that for passages to the flow regulating tube from the main supply tube. Although the passages constituting each inlet are collectively much larger in cross section than the flow regulating tube so as not to introduce much pressure drop, they individually are each smaller in cross section than the flow regulating tube, and therefore serve as a filter to block large particles from entering the flow regulating tube. Another feature of the invention is a series of discrete visible protrusions from the outer rib like bead of contrasting color to the rest of the irrigation hose. These protrusions serve as a bar code to identify the characteristics, size, thickness, flow rate, etc., of the hose.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view, partly in section, of a length of drip irrigation hose illustrative of one embodiment of the invention;

FIG. 2 is a cross-sectional view of the hose of FIG. 1 taken along the line 2-2 of FIG. 1;

FIG. 3 is a cross-sectional view of the hose of FIG.l taken along the line 3-3 of FIG. 1; FIG. 4 is a top sectional view of a short length of drip irrigation hose in the outlet area illustrating an inserted extension tube;

FIG. 5 is a top view, partly in section, of a length of drip irrigation hose illustrative of another embodiment of the invention; and

FIG. 6 is an enlarged view of part of the flow regulating tube of FIG. 5 illustrating the preferred construction of the teeth and the sidewalls of the flow regulating tube. DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

In the embodiment shown in FIG. 1, the drip irrigation hose is formed of an elongated flat sheet, i.e. film 10 of flexible water impervious material, which may, for example, be a laminate of high density polyethylene and polypropylene, and which has sufficient hickness to withstand the water pressures involved. The irrigation hose, of course, may be made from other materials, and may be laminated, extruded, or of other appropriate construction.

Spaced apart ribs 16 and 18 are die-formed adhesive beads and molded to one surface of sheet 10 adjacent to the edge of the sheet, this being achieved, for example, by using high-speed rotary dies, or other appropriate well-known forming means, all of which are intended to be embraced under the designation "die-formed". As shown, part of the inner walls of the rib like beads 16 and 18 are die formed to provide a series of weirs, the purpose of which is explained below. Preferably, the adhesive beads are first extruded onto one surface of the film 10 as a straight uninterrupted bead and are then interrupted and shaped into the described pattern by rotary die wheels.

Sheet 10 is then bent along its length, and its other surface is bonded or otherwise attached to the rib like beads to form an overlapping longitudinal seam between interior margin 12 and exterior margin 14 of sheet 10. The opposing faces of margins 12 and 14 are in juxtaposed relationship to each other. The longitudinally extending die-formed rib like beads 16 and 18 are precisely dimensioned, particularly their height, i.e. their protrusion from the surface of sheet

10, are precisely shaped, particularly their inner surfaces, and are precisely spaced. Rib like beads 16 and 18 serve to interconnect the margins 12 and 14 an to seal the overlapping longitudinal seam along which the rib like beads extend. It is advantageous for margin 14 only partially to cover rib like beads 16 as shown in FIG. 1 and to construct rib like beads 16 and 18, or at least rib like beads 16, from a material having a contrasting color, e.g. yellow, from the color, e.g. black, of sheet 10. It is only important that enough of the margin 14 covers bead 16 to insure a good physical connection therewith. As a result, a precisely dimensioned and shaped water flow regulating tube, which closely controls the flow rate and mode, i.e. turbulent, of the water emitted from the hose, is defined by rib like beads 16 and 18, and by margins 12 and 14. Staggered weirs are formed on the inner walls of the rib like beads causing turbulence in the water flowing through the flow regulating tube, this being desirable for the reasons set forth above. Specifically, the weirs are formed as pointed teeth 21 protruding from rib like bead 16 extending toward rib like bead 18 and pointed teeth 23 protruding from rib like bead 18 extending toward rib like bead 16 between the teeth from rib like bead 16. Pockets 25 and 27 are formed between teeth 21 and 23, respectively. As a result, a turbulent preferably serpentine path 17 for water flow is formed along the length of the flow regulating tube. The dimensions and shape of the rib like beads, and the spacing between the rib like beads, may be precisely controlled to establish the desired turbulent flow rate for the irrigation hose with a high degree of accuracy.

In FIG. 5, is shown another drip irrigation hose that illustrates the preferred embodiment of the turbulent serpentine path 17. Like reference numerals are used to identify elements in common with the drip irrigation hose of FIG. 1. To create and maintain maximum turbulence over a broad range of operating pressures the teeth and the pockets formed therebetween have some or all of the following characteristics illustrated in FIG. 6, which is an enlargement of the hose FIG. 5, the preferred embodiment of the turbulent serpentine path 17 of the flow regulating tube. Teeth 21 and 23 are angled, preferably at about 45 degrees, in an upstream direction, i.e. facing toward the flowing water whose direction is indicated by a arrow 26. Teeth 21 and 23 both extend from the sidewalls of the flow regulating tube precisely to a point slightly, e.g. 2 mil, past the center line 31 of the flow regulating tube. Adjacent to the point of teeth 21 and 23, is a flat surface 33, facing upstream and normal to center line 31. The shape and size of pockets 25 and 27 are designed to keep the water flow in turbulence during its passage between teeth 21 and 23 and to prevent water currents from forming boundary layers or becoming laminar. Specifically, the surface of pockets 25 and 27 between the points of teeth 21 and 23 is asymmetrical about an axis normal to the center line 31 and continuously curved without discontinuities in which water or air could easily become trapped. To promote turbulence between teeth 21 and 23, the length of pockets 25 and 27 along center line 31 is large relative to the thickness of teeth 21 and 23, e.g. two or more times as long as the tooth thickness at the root. Typical dimensions for teeth 21 and 23 and pockets 25 and 27 are as follows: pitch of teeth—134 mil; opposing teeth half pitch offset—67 mil; distance from point of teeth to inside edge of rib like beads—70 mil (2 mil over center line) ; tooth to rib like bead filet radius on downstream face of tooth—62 mil; tooth to rib like bead filet radius o upstream face of tooth—3 mil maximum; and toot thickness at root—75 mil.

The flow regulating tube includes inlets 22 (FIGS. 1 and 5) spaced along the hose and outlets 24 als spaced along the hose as shown. Inlets 22 are formed a interruptions in rib like beads 18 along the length o margin 12. The inlets 22 are each defined by th passages between a multiplicity of longitudinally space small die-formed button-like members 26 molded, o otherwise attached to the outer surface of the shee adjacent to margin 12, and heat sealed, or otherwis attached to the inner surface of the sheet adjacent t margin 14. These small die-formed members provide a entrance for water into the flow regulating tube. Th cross-sectional area of each passage between the members 26 is preferably smaller than the cross-sectional are of the flow regulating tube, so that the inlets may ac as a filter, but, the collective cross sectional area of all the passages forming each inlet is substantiall larger than the cross sectional area of the flo regulating tube so the flow rate is not affected if some of the passages become clogged.

The outlets 24 are each formed by interrupting th rib like bead 16. The length of the outlet is sufficiently large to assure that it does not restric the flow and so that the outer margin 14 may flex to ai in excluding foreign matter in the entrance and allo the water pressure to open it up to flush any deposits that might accumulate. Protecting the opening of eac outlet 24 is a diverter 28 which is molded or otherwis attached to the outer surface of the sheet margin 12. Diverter 28 could be formed by a lateral jog in rib lik bead 16 as shown in FIG. 1 or by a narrowing of th width of bead 16 so as to form the outlet between th top edge of diverter 28 and the adjacent edge of margi 14. (In the latter case, rib like bead 16 would simply be wider than shown in FIG. 1 between diverters 28, as represented by a phantom line 29.) Thus, outlets 24 each face upwardly out of the plane of FIG. 1. The diverter is located beyond the edge of margin 14 and is not attached to it. The diverter deflects away from outlets 24 root growth and soil that would otherwise have a tendency to work their way into the outlets. Thus, margin 14 in the area of the diverter is free to flex, thereby facilitating the egress of water from the drip irrigation hose.

Preferably, each regulating serpentine turbulent path 17 extends all the way from inlet 22 to outlet 24 and its length is selected for the pressure range of operation to insure turbulent flow over the entire distance between inlet 22 and outlet 24. If the regulating serpentine turbulent path 17 is too short, turbulent flow might _s not be established. If the regulating serpentine turbulent path is too long, all the turbulence of the water may become dissipated before outlet 24 and thus the sediment in the water may settle and clog the flow regulating tube near outlet 24. The turbulent serpentine path for a flow regulating tube having the dimensions set forth above and the characteristics depicted in FIG. 5 would typically be between 3 and 4 inches for a pressure range of 2 to 16 psi.

The rib like bead 16 may additionally have visible protrusions 36 colored to contrast with the rest of the hose to serve as a bar code or the like, for conveying information as to the size, thickness, flow rate, etc., of the particular hose. The exposed portions of the bar code protrusions 36 may be read mechanically, manually, or electronically, to derive the correspondin information. Additionally, the adhesive may be of contrasting color, e.g. yellow, in relation to the colo of the sheet 10, e.g. black, so as to allow the bar cod protrusions 36 to be easily read and easy to locate th diverter 28, and hence the outlet 24. This provides a easily seen continuous stripe to aid in properl orienting the outlets 24 in the desired "up" positio during installation.

As shown in FIG. 1, a cross rib like bead 32 i shaped to extend between rib like beads 16 and 18 fro one side of the flow regulating tube to the other a each inlet. This configuration separates the flo regulating tube into a series of longitudinal sections, with each section extending between one inlet 22 and on outlet 24. Weirs 20 could be formed along the entir length of rib like beads 16 and 18 between each inlet 22 and outlet 24 or could be formed along only a portio thereof depending upon the application and whether o not turbulence along the entire flow regulating channel is desired. Typically, the thickness of, sheet 10 would be o the order of 4 to 15 mil. Typical dimensions for sheet thickness of 8 mil and eight inch outlet sparin are as follows: width of rib like beads —50 mil; height of rib like beads— 5 to 20 mil; spacing betwee rib like beads disregarding teeth—130 mil. Typica lengthwise dimensions for each repetition of the hos pattern are as follows: length of inlets 22—3. inches; length of turbulent path—3.4 inches; length o direct channel between teeth and outlet—0.7 inch; length of outlet—0.1 inch; cross sectional area of eac inlet passage—.0004 in.²; and cross sectional area o flow regulating tube--.0008 in.². Typically, th diameter of the hose is 5/8 inch.

Preferably, the length of inlets 22, i.e. th number of members 26, varies depending on the outle spacing for a hose having a given flow rate and the other dimensions of the hose, including the length of the turbulent path (i.e. 3.4 inches), stay the same. Thus, the flow rate remains the same regardless of the outlet spacing and only the inlet length changes. For example, if the outlet spacing is eight inches, twelve -inches, or twenty-four inches, the length of inlet 22 may be 3.9 inches, 7.9 inches, or 19.9 inches, respectively. In general, the length of inlets 22 is preferably of the order of or greater than the length of the turbulent serpentine path, e.g. 3.4 inches, to provide a large effective inlet area.

As described, the series of passages between each group of longitudinally spaced members 26 forms an inlet port 22 for the flow regulating tube; each root and soil diverter 28, protects each outlet 24, of the flow regulating tube 34; and protrusions 36 serve as a bar code, or the like, for information purposes as explained above. The outlets, as shown, are displaced longitudinally from the respective inlets so that water must travel a substantial distance through the flow regulating tube from each inlet to a respective outlet. The length of travel and the cross sectional area of the flow regulating tube determine the flow rate of the hose.

Water flowing through the interior 30 of the hose also flows through the inlets 22 between the members 26, which form the inlet filters referred to above, into the flow regulating tube which serves as a secondary water distribution passage. The restricted cross-section of the regulating tube 34, the turbulence generated by the weirs 20, and the distance of travel therethrough control, i.e. regulate, the flow of water in the regulating tube, and thereby regulate the flow of water through the outlets 24. Thus, the outlets themselves may have a sufficiently large opening so as not to be susceptible to plugging. In addition, the flow within the regulating tube is of sufficient velocity and turbulence when operating under normal conditions to provide self- cleaning.

As mentioned above, cross rib like bead 32 serves to divide the flow regulating tube into a series of mutually isolated longitudinal sections, with each section extending between one of the inlets 22 and one of the outlets 24.

As taught in my referenced patent, rib like beads 16 and 18 must have sufficient height, e.g. to separate the interior and exterior margins 12 and 14 of the lapped seam which defines the regulating tube. Otherwise sufficient water would be prevented from flowing from the inlets 22 to the outlets 24.

As shown in FIG. 4, an alternate outlet 42 defined by elongated rib like beads 44 and 46 may be so configured to receive a flow extension tube 48 to convey the water leaving the flow regulating tube to a position other than adjacent to the outlet 42. Specifically, alternate outlet 42 is formed by curving rib like beads 44 and 46 gradually toward outlet 42, which in this case faces in a direction lying in the plane of the paper in FIG. 4. Therefore, tube 48 is installed by moving its end in the plane of the paper in FIG. 4 toward outlet 42. The curvature of rib like beads 44 and 46 guides the end of tube 48 smoothly into the flow regulating tube of the hose.

Specifically, uniformity of water flow is achieved because the flow regulating tube sections are essen¬ tially fed in parallel by the full static pressure of the interior 30 of the drip irrigation hose, and not through a long low pressure secondary regulator tube. This feature also serves to reduce the requirement to level or contour fields being watered by the hose, or for the precise placement of the hose in the field.

The filters formed by the members 26 at the inlets to the regulating tube sections protect the regulating tube sections from clogging. The filters are self- cleaning as the water is turned on and off. Specifically, the reverse water flow from the flow regulating tube sections to the interior 30 of the hose when the water is turned off causes the filters to be back flushed.

The flow regulating tube of the hose of the present invention may have configurations other than those shown in FIGS. 2 and 3, for example, such as shown in FIGS. 7, 8 and 9 of Patent 4,247,051.

The invention provides, therefore, an improved drip irrigation hose which may be manufactured simply and inexpensively, and which is reliable in operation and has little tendency to clog. By die-forming rib like beads 16 and 18, including weirs 20 and bar code protrusions 36, members 26, diverters 28 and cross rib like beads 32 of the flow regulating tube in a single operation, the flow regulating tube may be precisely sized, resulting in highly accurate flow rates. In addition, by forming the interior walls of the rib like beads into series of weirs, a desired turbulence in the water flowing through the flow regulating tube is achieved.

It will be appreciated that, while particular embodiments of the invention have been shown and described, modifications may be made. It is intended in the claims to cover all modifications which come within the true spirit and scope of the invention. For example, cross members 32 could be eliminated to permit flow of water in both directions from inlets 22 toward outlets 24; inlets 22 and/or outlets 24 could be formed in other ways if desired such as by apertures in the sheet 10; and the described characteristics of teeth 21 and 23 and pockets 25 and 27 (FIG. 6) can be selectively used to practice the invention depending upon desired degree of turbulence. Although it is preferable to form the turbulent flow path as shown in FIG. 6, some of the features of the invention can be practiced with other path configurations that induce turbulent flow.

Claims

I CLAIM:

1. A drip irrigation hose for handling water above a minimum pressure, the hose comprising: an elongated flat sheet of flexible water impervious material bent along its length to form a overlapping longitudinal seam between opposing inner and outer longitudinal margins of the sheet; first and second longitudinally extending rib like adhesive beads interconnecting the opposing margins to seal the overlapping seam and to form a flow regulating tube defined by the rib like beads and the margins; a plurality of inlets to the flow regulating tube distributed at intervals along the hose; a plurality of outlets from the flow regulating tube distributed at intervals along the hose displaced from the respective inlets to provide predetermined path lengths through the flow regulating tube from the inlets to the outlets; and a first series of tooth like weirs formed on the inside of the first rib like adhesive bead and a second series of tooth like weirs formed on the inside of the second rib like adhesive bead to form a turbulent flow regulating path over the entire distance between the inlets and the outlets, the turbulent path being sufficiently short relative to the minimum pressure to discharge water from the outlets before the turbulence is dissipated.

2. The drip irrigation hose defined in claim 1, in which the weirs are angled toward the inlets.

3. The drip irrigation hose defined in claim 1, in which the weirs are angled toward the inlets at about 45 degrees to the length of the flow regulating path.

4. The drip irrigation hose defined in claim 2, in which the first series of weirs are spaced midway between the second series of weirs.

5. The drip irrigation hose defined in claim 4, in which the weirs are pointed and continuously curved pockets are ormed between the weirs to promote maximum turbulence.

6. The drip irrigation hose defined in claim 5, in which a tangent to the surface of each weir facing toVard the inlets at the point is approximately normal to the length of the flow regulating tube.

7. The drip irrigation hose defined in claim 1, in which each inlet comprises a series of passage forming interruptions in the rib like bead closest to the inner margin, each passage having a cross sectional area appreciably smaller than the flow regulating tube to filter out particles.

8. A drip irrigation hose comprising: an elongated flat sheet of flexible water impervious material bent along its length to form a overlapping longitudinal seam between opposing inner and outer longitudinal margins of the sheet; first and second longitudinally extending rib like adhesive beads interconnecting the opposing margins to seal the overlapping seam and to form a flow regulating tube defined by the rib like beads and the margins; a plurality of inlets to the flow regulating tube distributed at intervals along the hose; a plurality of outlets from the flow regulating tube distributed at intervals along the hose displaced from the respective inlets to provide predetermined path lengths through the flow regulating tube from the inlets to the outlets; and a first series of tooth like weirs formed on the inside of the first rib like bead and a second series of tooth like weirs formed on the inside of the second rib like bead to form a turbulent flow regulating path between the inlets and the outlets, the weirs being angled toward the inlets.

9. A drip irrigation hose comprising: an elongated flat sheet of flexible water impervious material bent along its length to form a overlapping longitudinal seam between opposing inner and outer longitudinal margins of the sheet; first and second longitudinally extending rib like adhesive beads interconnecting the opposing margins to seal the overlapping seam and to form a flow regulating tube defined by the rib like beads and the margins; a plurality of inlets to the flow regulating tube distributed at intervals along the hose, the inlets being formed from passage defining interruptions in the rib like bead closest to the inner margin, the cross sectional area of the passages being less than the flow regulating tube; and a plurality of outlets from the flow regulating tube distributed at intervals along the hose displaced from the respective inlets.

10. A drip irrigation hose comprising: an elongated flat sheet of flexible water impervious material bent along its length to form a overlapping longitudinal seam between opposing inner and outer longitudinal margins of the sheet; first and second longitudinally -extending ribs interconnecting the opposing margins ±o seal the overlapping seam and to form a flaw xεgulating tube defined by the ribs and the margins; a plurality of inlets to "the flow regulating tube distributed at intervals along the hose; a plurality of outlets from the flow regulating tube distributed at intervals along the hose displaced from the respective inlets to provide predetermined path lengths through the flow regulating tube from the inlets to the outlets; and a plurality of visible protrusions from the outside of the rib closest to the edge of the outer margin identifying characteristics of the hose.

11. A method for constructing a drip irrigation hose comprising the steps of: forming at least two adhesive beads on the surface of opposing longitudinal margins of an elongated flat sheet of flexible water impervious material; bending the sheet along its length to form a flow regulating tube defined by the beads and the opposing margins and to form a supply tube defined at least in part by the remainder of the sheet; forming a plurality of inlets to the flow regulating tube from the supply tube; and forming a plurality of outlets from the flow regulating tube displaced from the respective inlets to provide a substantial path length from each inlet to a respective outlet; in which the improvement comprises forming the beads so they introduce turbulence along the path length from each inlet to a respective outlet.

12. The method of claim 11, in which the improvement further comprises forming the beads so they have staggered teeth like weirs to introduce the turbulence.