U.S. patent application number 15/365952 was filed with the patent office on 2017-03-23 for delivery tube for irrigation and fertilization system and method for manufacturing same.
This patent application is currently assigned to Responsive Drip Irrigation, LLC. The applicant listed for this patent is Responsive Drip Irrigation, LLC. Invention is credited to David A. Conklin, Janice K. Gould.
Application Number | 20170080640 15/365952 |
Document ID | / |
Family ID | 53269800 |
Filed Date | 2017-03-23 |
United States Patent
Application |
20170080640 |
Kind Code |
A1 |
Gould; Janice K. ; et
al. |
March 23, 2017 |
DELIVERY TUBE FOR IRRIGATION AND FERTILIZATION SYSTEM AND METHOD
FOR MANUFACTURING SAME
Abstract
The invention is directed generally to improvements in
irrigation and fertilization assessment and delivery. More
specifically, embodiments of the invention provide an improved
fluid delivery tube, method to manufacture such tube, and systems
that include such tube. The delivery tube is beneficial at least
because it minimizes the life cycle cost of a responsive delivery
tube.
Inventors: |
Gould; Janice K.;
(Bradenton, FL) ; Conklin; David A.; (Bradenton,
FL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Responsive Drip Irrigation, LLC |
Bradenton |
FL |
US |
|
|
Assignee: |
Responsive Drip Irrigation,
LLC
Bradenton
FL
|
Family ID: |
53269800 |
Appl. No.: |
15/365952 |
Filed: |
December 1, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14625572 |
Feb 18, 2015 |
9527267 |
|
|
15365952 |
|
|
|
|
13968447 |
Aug 16, 2013 |
9309996 |
|
|
14625572 |
|
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|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29C 66/71 20130101;
B32B 37/0076 20130101; B32B 2325/00 20130101; B29L 2031/7004
20130101; B32B 2386/00 20130101; B29C 66/432 20130101; B29C 65/18
20130101; B29C 66/71 20130101; B32B 1/08 20130101; B29C 66/73172
20130101; B29C 66/71 20130101; B32B 2307/728 20130101; B29C 66/712
20130101; B32B 38/0004 20130101; B29C 66/7294 20130101; B32B
2597/00 20130101; A01G 25/02 20130101; B29C 2793/009 20130101; B29C
65/08 20130101; B29C 66/71 20130101; B29C 66/83411 20130101; B29C
66/133 20130101; B29C 66/1122 20130101; B29C 66/71 20130101; B29C
66/21 20130101; B29C 66/232 20130101; B29C 65/02 20130101; B29K
2023/06 20130101; B29K 2023/0625 20130101; B29K 2023/0633 20130101;
B29K 2023/12 20130101 |
International
Class: |
B29C 65/00 20060101
B29C065/00; B29C 65/18 20060101 B29C065/18; B32B 1/08 20060101
B32B001/08; A01G 25/02 20060101 A01G025/02; B32B 37/00 20060101
B32B037/00; B29C 65/08 20060101 B29C065/08 |
Claims
1. A method for manufacturing a delivery tube, the method
comprising: preparing a hydrophilic polymer solution; coating a
portion of a substrate with the hydrophilic polymer solution to
produce a responsive substrate; drying the responsive substrate;
and welding the responsive substrate to a backer to form the
delivery tube, the coating being a surface treatment, the welding
not operating on the portion of the substrate coated with the
hydrophilic polymer.
2. The method of claim 1, wherein the substrate includes nonwoven
polyethylene and the backer includes polyethylene.
3. The method of claim 2, wherein the backer includes nonwoven
polyethylene.
4. The method of claim 2, wherein the backer includes metallocene
polyethylene.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a Continuation-in-Part (CIP) of U.S. application
Ser. No. 13/968,447, which was filed on Aug. 16, 2013.
BACKGROUND
[0002] 1. Field of the Invention
[0003] The invention relates generally to irrigation and
fertilization systems and methods, and more particularly, but
without limitation, to an improved delivery tube that can
more-efficiently satisfy plant hydration and nutrition needs.
[0004] 2. Description of the Related Art
[0005] Agronomic practices include various irrigation and
fertilization assessment and delivery methods. Typically, growers
measure environmental conditions (i.e. rainfall, soil moisture, pH,
temperature, etc.) and/or observe plant development to determine an
amount of water and fertilizer to apply during a plant's growing
season. Well-known methods also exist for providing the irrigation
and fertilization; for instance, sprinkler systems and drip lines
are commonly utilized.
[0006] Conventional assessment methods and delivery systems have
many shortcomings, however. For example, assessment methods that
rely on data measurements and observations to estimate plant needs
are reactive. Accordingly, such methods necessarily introduce a
time delay between the assessment and the delivery of the water and
fertilizer. Sufficiently long delays can stress the target plants
and/or decrease the value of the assessment (since the measured
conditions may quickly change). In addition, such assessments often
lack geographical precision, which may be disadvantageous, for
instance, where moisture conditions vary substantially within a
crop field due to changes in elevation or other factors.
[0007] Even if the needs assessment is correct, timely, and
sufficiently precise, conventional irrigation and fertilization
delivery systems often fail to provide the desired level of water
and/or nutrients to each plant. There are many reasons for this.
For example, in an irrigation system, static water pressure can
vary based on distance from the water source, field topography,
and/or leaks or other component failure. Distributed controls that
would overcome such system limitations, and also enable delivery of
water and nutrients according to the demand of each plant, are
generally cost prohibitive. As a result, many delivery systems
apply too little or too much water and nutrients. This decreases
crop yield. The application of too much water is a waste of a
precious natural resource; the application of too much fertilizer
can harm the environment.
[0008] Given the importance of food supply, water management, and
the need to protect the environment, improvements in irrigation and
fertilization assessment and delivery methods are urgently
needed.
SUMMARY OF THE INVENTION
[0009] Embodiments of the invention seek to overcome one or more of
the aforementioned limitations with an improved delivery tube,
method to manufacture such tube, and/or systems that include such
tube.
[0010] An embodiment of the invention provides a delivery tube that
includes: a substrate, no portion of the substrate being treated
with a hydrophilic polymer; and a backer coupled to the substrate
at a first weld and a second weld, no portion of the backer being
treated with the hydrophilic polymer, the delivery tube being
configured such that the substrate and the backer are each disposed
along a functional length of the delivery tube.
[0011] An embodiment of the invention provides a delivery tube that
includes a substrate, at least a portion of the substrate being
treated with a hydrophilic polymer; and a backer coupled to the
substrate, no portion of the backer being treated with the
hydrophilic polymer, the delivery tube being configured such that
the substrate and the backer are each disposed along a functional
length of the delivery tube, the substrate and the backer each
including Dupont Tyvek.
[0012] An embodiment of the invention provides a delivery tube that
includes a substrate, a first portion of the substrate being
treated with a hydrophilic polymer, a second portion and a third
portion of the substrate not being treated with the hydrophilic
polymer; and a backer welded to the second portion and the third
portion of the substrate, the delivery tube being configured such
that the substrate and the backer are each disposed along a
functional length of the delivery tube.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The invention will be more fully understood from the
detailed description below and the accompanying drawings,
wherein:
[0014] FIG. 1 is a schematic diagram of an irrigation and
fertilization system, according to an embodiment of the
invention;
[0015] FIG. 2 is a schematic diagram of an irrigation and
fertilization system, according to an embodiment of the
invention;
[0016] FIG. 3 is an assembly view of a delivery tube, illustrated
in cross-section, according to an embodiment of the invention;
[0017] FIG. 4 is a plan view of a delivery tube, according to an
embodiment of the invention;
[0018] FIG. 5 is an end view of a partially-opened delivery tube,
according to an embodiment of the invention;
[0019] FIG. 6 is an end view of a partially-opened delivery tube,
according to an embodiment of the invention;
[0020] FIG. 7 is an end view of a partially-opened delivery tube,
according to an embodiment of the invention;
[0021] FIG. 8 is an end view of a delivery tube, according to an
embodiment of the invention;
[0022] FIG. 9 is a flow diagram of a method for manufacturing a
delivery tube, according to an embodiment of the invention;
[0023] FIG. 10 is a schematic diagram of a coating apparatus,
according to an embodiment of the invention;
[0024] FIG. 11 is a schematic diagram of a coating apparatus,
according to an embodiment of the invention;
[0025] FIG. 12 is a schematic diagram of a coating apparatus,
according to an embodiment of the invention;
[0026] FIG. 13 is a plan view of a delivery web subsequent to a
welding step, according to an embodiment of the invention; and
[0027] FIG. 14 is a plan view of a three delivery tubes, according
to an embodiment of the invention.
DETAILED DESCRIPTION
[0028] Embodiments of the invention will be described more fully
with reference to FIGS. 1 to 14, in which embodiments of the
invention are shown. This invention may, however, be embodied in
many different forms and should not be construed as limited to the
embodiments set forth herein. The sub-headings below are for
organizational convenience only, and features of the invention may
be described anywhere in this specification. In the drawings,
physical features are not necessarily rendered to scale. Where
identical reference numbers are repeated, they refer to the same or
substantially similar features.
Exemplary Systems
[0029] Embodiments of the invention can be used on farms of varying
scale. FIG. 1 is a schematic diagram of an irrigation and
fertilization system, according to an embodiment of the invention.
The embodiment illustrated in FIG. 1 might be applicable, for
instance, to a family farm or other small plot. As shown therein, a
small plot supply system 105 is configured to harvest rain water.
The small plot supply system 105 feeds a header pipe 110 that is
coupled to multiple delivery tubes 115 via fittings 125. Crops 120
are disposed adjacent to each of the delivery tubes 115.
[0030] The small plot supply system 105 includes roof gutters 130
positioned to cooperate with a roof 135. Downspouts 140 are coupled
to the gutters 130 at an input end and disposed over a storage tank
145 at an output end. The storage tank 145 could be or include, for
instance, and elevated plastic 55-gallon drum. The storage tank 145
is configured with a lid 150 having a screen filter 155. The
storage tank 145 further includes an overflow outlet 160. An
isolation valve 165 is disposed inline between the storage tank 145
and a supply system output 170.
[0031] Preferably, each delivery tube 115 includes a responsive
portion along its length that is hydrophilic and configured to
deliver water or an aqueous solution in response to surfactant root
exudate from a root system of the crops 120. In other words, each
section of each delivery tube 115 is configured to efficiently
deliver water or other solution according to individual crop demand
rather than at a regulated rate provided, for example, by sprinkler
and drip-based irrigation systems.
[0032] As used herein, the term "delivery tube" refers generally to
a device for fluid conveyance along a length of the delivery tube
and through at least a portion of its walls, and is not intended to
restrict the physical form of such device to one having a circular
cross-section. For instance, in embodiments of the invention the
delivery tubes 115 are "tape-like" with a relatively flat
cross-section when unfilled with a fluid. Alternative
configurations for the delivery tubes 115 are described in more
detail below with reference to FIGS. 3-8.
[0033] During periods of rain, the gutters 130 and downspouts 140
direct rain water to the storage tank 145. The screen filter 155
filters solid particles from the rain water as it enters the
storage tank 145. If water in the storage tank 145 exceeds a
predetermined maximum water level 157, excess water is discharged
from the storage tank 145 via the overflow outlet 160.
[0034] The size of storage tank 145 and the change in elevation
between the maximum water level 157 and the supply system output
170 determine a maximum pressure provided by the small plot supply
system 105. In embodiments of the invention, the desired pressure
at the supply system output 170 is relatively low, for instance
within the range of 0.5-2.1 lb/in.sup.2 (PSI), for compatibility
with the delivery tubes 115. The desired pressure at the supply
system output 170 will vary accordingly to the particular
configuration of the delivery tubes 115, however.
[0035] The isolation valve 165 could be closed, for instance,
during periods of rain (when the crops 120 are unlikely to need
hydration) or during maintenance of the downstream irrigation
system. When the isolation valve 165 is open, the header pipe 110
supplies rain water to pressurize the delivery tubes 115. Once
pressurized, the delivery tubes 115 supply the filtered rain water
to the crops 120 in response to the root exudates.
[0036] Variations to the system illustrated in FIG. 1 and described
above are possible. For example, in alternative embodiments, the
small plot supply system 105 may further include a well water feed
and/or municipal water feed to supplement the rain-harvesting
features in filling the storage tank 145. Such additional feed(s)
could be activated, for example, by a float valve in the storage
tank 145. There could be more than one storage tank 145 coupled to
the supply system output 170. In addition, one of more filters
could be placed in-line between the storage tank(s) 145 and the
supply system output 170 in addition to, or instead of, the screen
filter 155. In alternative embodiments, the small plot supply
system 105 includes a fertilizer injection subsystem. End caps and
flush valves are not shown in FIG. 1 but are preferably coupled to
the header 110. Likewise, each of the delivery tubes 115 may be
crimped or capped at a terminal end; alternatively, multiple
delivery tubes may be joined by a footer and such footer may
include end caps and/or a flush valve.
[0037] FIG. 2 is a schematic diagram of an irrigation and
fertilization system, according to an embodiment of the invention.
The embodiment illustrated in FIG. 2 might be applicable, for
instance, to a large commercial farming operation. As shown
therein, a commercial grower supply system 205 feeds a header pipe
110 that is coupled to multiple delivery tubes 115 via fittings
125. Crops 120 are disposed adjacent to each of the delivery tubes
115.
[0038] The commercial grower supply system 205 includes a well pump
210 coupled to a source line 213. A fertilizer reservoir 215 is
also coupled to the source line 213 via a pump 220 and metering
valve 225. Each of multiple chemical injection tanks 230 are
connected to the source line 213 via a corresponding metering valve
235. Filters 240, pressure regulator 245, and pressure meter 250
are disposed in series between the source line 213 and a system
supply output 255. The commercial grower supply system 205 feeds a
header pipe 110 that is coupled to multiple delivery tubes 115 via
fittings 125. Crops 120 are disposed adjacent to each of the
delivery tubes 115.
[0039] The pressure regulator 245 is configured to output a
relatively low-pressure regulated fluid flow, for instance for a
setting within the range of 0.5-2.1 PSI, for compatibility with the
delivery tubes 115. An exemplary regulator 245 is the Model 102
diaphragm regulator manufactured by Ziggity Systems, Inc. The
desired pressure setting for such an adjustable pressure regulator
will vary accordingly to the particular configuration of the
delivery tubes 115. In alternative embodiments, other pressure
settings and/or other regulators 245 could be used.
[0040] In operation, the commercial grower supply system 205
supplies filtered water or a filtered aqueous solution including
fertilizer and/or chemicals at a predetermined (and relatively low)
pressure via a header pipe 110 to delivery tubes 115. The
pressurized delivery tubes 115 supply the water or aqueous solution
including soluble fertilizers in response to root exudates from the
crops 120.
[0041] Variations to the system illustrated in FIG. 2 and described
above are possible. For example, in alternative embodiments, the
commercial grower supply system 205 could include a municipal water
feed to supplement the water supply from the well pump 210. The
commercial grower supply system 205 may not include the chemical
injection tanks 230 and associated metering valves 235. Moreover,
the type and quantity of filters 240 could vary, according to
design choice. An isolation valve could be included, for instance
between the pressure meter 250 and the supply system output 255.
End caps and flush valves are not shown in FIG. 1 but are
preferably coupled to the header 110. Likewise, each of the
delivery tubes 115 may be crimped or capped at a terminal end;
alternatively, multiple delivery tubes may be joined by a footer,
and such footer may include end caps and/or a flush valve.
Delivery Tubes
[0042] Alternative configurations of the delivery tubes 115 are
described below with reference to FIGS. 3-8. FIG. 3 is an assembly
view of a delivery tube, illustrated in cross-section, according to
an embodiment of the invention. As shown therein, an embodiment of
the delivery tube 115 is generally an assembly of a responsive side
305 to a backing side 310. The responsive side 305, or at least a
portion thereof, is preferably responsive to root exudate from a
root system of the crops 120. In alternative embodiments, the
responsive side 305 releases water, liquefied nutrients, and/or
other fluids based primarily on fluid supply pressure or a
combination of supply pressure and other factors. The backing side
310 is a supporting structure. In the embodiment illustrated in
FIG. 3, the resulting delivery tube 115 is essentially a
"tape-like" or "lay flat" structure when not in use. The tape-like
format is advantageous because the delivery tube 115 can be
compactly spooled (reeled) for storage and distribution. The
responsive side 305 includes a substrate that is treated with a
hydrophilic polymer solution to make it responsive to root
exudates. The substrate preferably includes a nonwoven fabric of
petroleum-based plastic polymers, for instance polyethylene (PE) or
polypropylene (PP).
[0043] Acceptable nonwoven PE fabrics for the responsive side 305
include, for instance, DuPont Tyvek (1025BL, 1025D, 1053B, 1053D,
1056D, 1058D, 1059B, 1073B, 1073D, 1079, 1079B, 1079D, or 1085D).
Suitable nonwoven PP fabrics for the responsive side 305 include,
for example, Fibertex Spuntex 55, Hanes Imperial RB2, Mitsui
Chemicals, Suzhou Mediceng (LB543 or WH001F), and related products.
Other PE and PP fabrics may also be suitable substrates, according
to application demands.
[0044] The responsive side 305 may be treated or untreated,
according to application needs. Suitable hydrophilic polymers for
treating the responsive side 305 include various Polyhydroxystyrene
(PHS) co-polymers, for example, Polyhydroxystyrene-Novolak
(PHS-Novolak), Polyhydroxystyrene-Benzotriazole (PHS-BZT), and
Polyhydroxystyrene Hydroxyethyl Methacrylate (PHS-HEMA). Other
hydrophilic polymers may also be used.
[0045] The backing side 310 may be or include, for example,
Metallocene Polyethylene (PE) from Brentwood Plastics, Inc.,
Low-Density Polyethylene (LDPE), Linear Low Density Polyethylene
(LLDPE), Copolymer polypropylene (PP) by Bloomer Plastics Inc.
(BPI) (e.g., the "random" and "impact" products), Homopolymer
polypropylene (PP) by BPI, Polyester (PET or polyethylene
terephthalate), and Urethane Film by Medco Coated Products (a
division of Medco Labs). Any of the nonwoven PE or PP fabrics
listed above as being suitable for the responsive side 305 could
also be used for the backing side 310. Other materials could also
be used for the backing side 310. The general requirements for the
material used for the backing side 310 are that it is water-proof,
weldable (bondable), reasonably durable for the target application,
and low cost. The backing side 310 material may have a thickness,
for example, in the range of 2 to 15 mils.
[0046] Various combinations of responsive side 305 and backing side
310 materials as possible for the manufacture of delivery tubes.
Preferably, a treated responsive side 305 is paired with a backing
side 310. For example, Dupont Tyvek or another nonwoven PE fabric
that has been treated with a hydrophilic polymer (the treated
responsive side 305) could be paired with untreated Dupont Tvvek or
another nonwoven PE fabric (the backing side 310). Alternatively,
untreated Dupont Tyvek (the responsive side 305) could be paired
with another untreated nonwoven PE fabric (the backing side) to
form a delivery tube. The pairing of similar fabrics (e.g., two PE
fabrics or two PP fabrics) may be preferable because it generally
produces stronger bonds than the pairing of dissimilar fabrics.
[0047] In embodiments with a treated responsive side 305, the
responsive side 305 requires hydrophilic treatment processing
before it is assembled to an untreated backing side 310. Such an
assembly may be less expensive than a delivery tube formed entirely
of treated material, however. The backing side 310 can also improve
the durability of the delivery tube 115 compared to a delivery tube
that is formed entirely of responsive material that has been
treated with hydrophilic polymers.
[0048] Various configurations of the delivery tube 115 are
described below with reference to FIGS. 4-8.
[0049] FIG. 4 is a plan view of a delivery tube, according to an
embodiment of the invention. Weld areas 405 bond edges of the
responsive side 305 to corresponding edges of the backing side 310.
The weld areas 405 provide a fluidic seal to contain water or an
aqueous solution in an interior cavity of the delivery tube 115.
The delivery tube 115 is intended for relatively low pressure
systems. Preferably, the seal formed by weld areas 405 should
withstand a burst pressure of at least 4.0 PSI. In the illustrated
embodiment, each weld area 405 includes three rows of intermittent
welds, the three rows being staggered with respect to each other.
Other weld patterns (intermittent or continuous) are possible.
[0050] FIG. 5 is an end view of a partially-opened delivery tube,
according to an embodiment of the invention. In the illustrated
embodiment, the responsive side 305 may be saturated with a
hydrophilic polymer solution over the full width shown in
cross-section.
[0051] FIG. 6 is an end view of a partially-opened delivery tube,
according to an embodiment of the invention. In the illustrated
embodiment, the hydrophilic polymer is disposed on a coated portion
615 of an outer surface of the substrate 605. Uncoated portions 610
of the substrate 605 extend into the weld areas 405. In one
respect, the configuration shown in FIG. 6 may be advantageous
because uncoated portions 610 of the substrate 605 may result in
stronger weld areas 405. Selective pattern coating on a surface of
the substrate 605 also reduces manufacturing cost relative to
saturation coating at least because less hydrophilic polymer may be
required.
[0052] FIG. 7 is an end view of a partially-opened delivery tube,
according to an embodiment of the invention. In the illustrated
embodiment, the hydrophilic polymer is disposed on a coated portion
715 of an inner surface of the substrate 705. Uncoated portions 710
of the substrate extend into the weld areas 405. The configuration
shown in FIG. 7 may also be advantageous because uncoated portions
710 of the substrate 705 may result in stronger weld areas 405.
Selective pattern coating on a surface of the substrate 705 also
reduces manufacturing cost relative to saturation coating at least
because less hydrophilic polymer may be required.
[0053] FIG. 8 is an end view of a delivery tube, according to an
embodiment of the invention. As shown therein, a delivery tube with
a circular cross-section includes a substrate 805 connected to a
backing 810 at overlap welds 815. In the illustrated embodiment,
the substrate 805 forms less than 50% of the delivery tube. The
substrate 805 includes a coated portion 825 and uncoated portions
820. The coated portion 825 represents hydrophilic polymer disposed
on an outer surface of the substrate 805. The uncoated portions 820
extend into the overlap weld areas 815. The ratio between the
substrate 805 and the backing 810 could be varied according to
design choice. Decreasing the size of the coated portion 825 and/or
the dry polymer weight applied to the coated portion 825 decreases
the amount of water or fertilizer solution that is released at a
given pressure.
Manufacturing Method
[0054] A manufacturing process for the delivery tube 115 is
described with reference to FIGS. 9-14.
[0055] FIG. 9 is a flow diagram of a method for manufacturing a
delivery tube, according to an embodiment of the invention. As
shown therein, the process begins in step 905 and then prepares a
hydrophilic polymer solution in step 910. Step 910 may include, for
instance mixing a dry hydrophilic polymer powder with a solvent
such as Isopropanol 99% (IPA). The concentration of hydrophilic
polymer in the solution may be based, for instance, on the target
substrate material, the desired concentration of dry hydrophilic
polymer on the substrate, and the coating method used. Suitable
concentrations of hydrophilic polymer in the solution may be in the
range of 2.0-89.0 weight/volume percent, and are preferably in
excess of 20 wt/vol % to facilitate high-speed coating methods
which reduce evaporation and minimize production costs.
[0056] In step 915, the process coats a substrate (or portion
thereof) with the hydrophilic polymer solution to produce a
responsive web. As used herein, a "coating" step could be a surface
treatment, saturation, or other application of the hydrophilic
polymer solution to the nonwoven substrate material. The process
dries the responsive web in step 920. The desired concentration of
dry hydrophilic polymer on the substrate will vary according to the
substrate material and other factors. As an example, polymer
weights in the range of 1.5-5.2 g/m.sup.2 have produced acceptable
results with Tyvek PE substrates.
[0057] Next, the process welds the responsive web to a backing film
to form a delivery web in step 925. Welding step 925 could be or
include, for example, rotary heat sealing, contact welding,
ultrasonic welding, or other plastic welding method. The delivery
web is then rolled (spooled) in step 930.
[0058] Preferably, steps 915-930 produce a multi-paneled delivery
web. In this instance, the process slits the delivery web to form
multiple delivery tubes in step 935 and then rewinds each of the
multiple delivery tubes in step 940 before terminating in step 945.
FIGS. 13 and 14 illustrate and exemplary multi-paneled delivery
web. Slitting step 935 may utilize, for example, one or more
razors, one or more pairs of opposing circular knives, or a slit
weld. Rewind step 940 may include rewinding each of the
manufactured delivery tubes onto a reel at a desired speed and
capacity.
[0059] Variations to the manufacturing method described above with
reference to FIG. 9 are possible. For instance, in embodiments
where the responsive side 305 of the delivery tube is untreated,
steps 910, 915, and 920 are not required. Rolling step 930 may not
be required for a continuous manufacturing flow. Slitting step 935
and rewind step 940 may be, and preferably are, combined into a
single process step. In addition, where steps 915-925 produce a
single-tube-width web rather than a multi-paneled web, steps 935
and 940 are not required at all. Exemplary coating methods for step
915 are presented below with reference to FIGS. 10-12, although
other coating methods could be used in the alternative.
[0060] FIG. 10 is a schematic diagram of a coating apparatus,
according to an embodiment of the invention. As illustrated, the
coating apparatus is configured so that a substrate web 1005 can
move in a direction 1010 in cooperation with pulleys 1025 and a
Mayer rod (a/k/a a rod doctor) 1030. A coating pan 1015 contains a
hydrophilic polymer solution 1020. In operation, the substrate web
1005 is dip coated with the hydrophilic solution 1020. The Mayer
rod 1030 operates to remove excess hydrophilic solution 1020 after
the substrate web 1005 has exited the coating pan 1015.
[0061] Variations to the dip-coating apparatus illustrated in FIG.
10 are possible. For instance the number and placement of the
rollers 1025 can vary according to design choice. In addition, the
use of a Mayer rod 1030 is optional.
[0062] FIG. 11 is a schematic diagram of a coating apparatus,
according to an embodiment of the invention. As shown therein, the
coating apparatus is configured so that a substrate web 1105 can
advance in a direction 1110 in cooperation with pulleys 1125, steel
roller 1130 and rubber roller 1135. A coating pan 1115 contains a
hydrophilic polymer solution 1120 and is at least partially covered
by a lid 1140. In operation, the substrate web 1110 passes through
openings 1145 and 1150 in the lid 1140 and is dip coated with the
hydrophilic solution 1120. The lid 1140 advantageously limits
evaporation of solvent in the hydrophilic solution 1120. The rubber
roller cooperates with the steel roller 1130 to remove excess
hydrophilic solution 1120 after the substrate web 1105 has exited
the coating pan 1115.
[0063] Variations to the configuration of the dip-coating apparatus
illustrated in FIG. 11 are possible. For instance the number and
placement of the rollers 1125 can vary according to design choice.
In addition, the use of a rubber roller 1135 is optional.
[0064] FIG. 12 is a schematic diagram of a coating apparatus,
according to an embodiment of the invention. The coating apparatus
is configured so that a substrate web 1205 can progress in a
direction 1210 between opposing rollers 1225 and 1230. The roller
1225 is a gravure roller having an engraved (or etched) surface.
The gravure roller 1225 is partially submerged in hydrophilic
polymer solution 1220 that is contained by the coating pan 1215.
Roller 1230 is a pressure roller configured to place a downward
force on the substrate web 1205. A scraper (doctor) blade is
disposed adjacent to the gravure roller 1225. In operation, the
gravure roller 1225 picks up hydrophilic polymer solution 1220 in
its engraved (or etched) surface. The scraper blade 12235 removes
excess hydrophilic polymer solution 1220 from a surface of the
gravure roller 1225. Remaining hydrophilic polymer solution 1220 is
deposited from the engraved (or etched) cavities of the gravure
roller 1225 to at least a portion of a surface of the substrate web
1205.
[0065] FIG. 13 is a plan view of a delivery web subsequent to a
welding step, according to an embodiment of the invention. FIG. 13
illustrates a delivery web 1305, for instance, after the welding
step 925 described above with reference to FIG. 9. In the
embodiment shown in FIG. 13 the delivery web 1305 includes six
linear weld areas 1310, each of the weld areas 1310 including three
staggered rows of intermittent welds. The weld patterns in each of
the weld areas 1310 could vary from what is shown.
[0066] FIG. 14 is a plan view of a three delivery tubes, according
to an embodiment of the invention. FIG. 14 illustrates the delivery
web 1305, for instance, after the slitting step 935 described above
with reference to FIG. 9. As shown, slit lines 1405 and 1410
separate the delivery web 1305 into three delivery tubes 1415,
1420, and 1425.
[0067] Although FIGS. 13 and 14 illustrate a 3-panel approach, a
manufacturing process that is configured for a greater or lesser
numbers of panels is also possible.
EXAMPLES
[0068] Preferably, delivery tubes are fabricated with a PE
substrate and PE backing, or with a PP substrate and a PP backing.
Example delivery tubes have been fabricated consistent with the
configuration illustrated in FIGS. 3-5. A first group of samples
used Tyvek 10598 PE substrates with a basis weight of 64.4 gsm and
a thickness range of 2.9 to 10.1 mils. A second group of samples
used Tyvek 1073 PE substrates with a basis weight of 74.6 gsm and a
thickness range of 3.5 to 11.1 mils. Samples from both groups were
coated using a gravure coating process to apply a dry hydrophilic
polymer coating at a weight of 5.0 to 5.3 gsm. The coated PE
substrates were bonded to a 5.0 mil thick Metallocene PE backer via
ultrasonic weld or rotary heat seal. The resulting delivery tubes
had an internal diameter of 5/8 to 7/8 inches. In agricultural
testing, the tubes were observed to be structurally robust and
locally responsive to plant hydration and nutrition needs.
SUMMARY
[0069] This specification has thus described an improved irrigation
and fertilization delivery tube, a method for manufacturing the
delivery tube, and exemplary systems utilizing the delivery tube.
As described above, embodiments of the invention utilize low-cost
materials and high-throughput manufacturing processes to produce a
responsive delivery tube. The result is a delivery tube that can be
sold at an affordable end-user price. The disclosed delivery tube
is also highly durable in use. Embodiments of the invention enable
a highly-efficient plant-responsive irrigation and fertilization
delivery system that is comparable in total life cycle cost to
less-efficient non-responsive drip irrigation systems. Other
embodiments provide delivery tubes that are responsive to regulated
supply pressure and/or other factors. The improved systems,
delivery tubes, and manufacturing processes disclosed in this
application can ultimately benefit both small-plot and commercial
farms.
[0070] It will be apparent to those skilled in the art that
modifications and variations can be made to the tube, its
manufacturing method, and/or its use in a system without deviating
from the spirit or scope of the invention disclosed herein.
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