Hybrid low flow and spray irrigation apparatus and method

An apparatus providing low volume irrigation from a previously installed sprinkler irrigation system including one or more sprinkler heads connected to a water supply conduit. The apparatus includes a manifold (50) having a water distribution passage (34) therein. The water distribution passage (34) includes an inlet end (35) and an outlet end (36) with the outlet end adapted to receive a conveyance channel (38) for distributing water to an emission point (42, 43). A flow control device (39) is associated with the water distribution passage (34) to control the flow rate of water through the passage to a rate exceeding a local hydraulic loading rate of the soil in the area around the emission point (42, 43). The manifold (50) is connected to receive water which is supplied to the sprinkler head through the water supply conduit. The manifold (50) may be connected to the sprinkler head body (22) or to the conduit (28) below the sprinkler head body and may replace the sprinkler type irrigation completely or supply irrigation supplemental to the sprinkler type irrigation.

BACKGROUND OF THE INVENTION 
This invention relates to irrigation, and more particularly to an apparatus 
and method for a hybrid low volume and sprinkler irrigation system. The 
invention provides a site selectable arrangement for providing a new, low 
volume method of irrigation along with a conventional irrigation method, 
both from a convention sprinkler head installation. 
Abroad and in the United States, a large percentage of potable, fresh water 
consumption is utilized for irrigating landscape and ornamental plantings. 
The state of the art irrigation systems utilized for delivering this water 
to landscape plantings are inefficient and contribute greatly to the 
exhaustion of water reserves in many areas. Sprinkler head systems are 
most commonly used for landscape purposes. The goal of a sprinkler head 
system is to evenly distribute the water through the air to a given area 
at a rate equivalent or less than the hydraulic loading rate or water 
infiltration rate of the surrounding soil. At this rate, the evenly 
distributed airborne water droplets fall to the ground and are absorbed 
into the soil. 
However, the tiny spray droplets necessary to achieve uniform water 
distribution are vulnerable to wind and are more often than not blown out 
of the area intended to be irrigated, contributing to the over spray 
problems. Run-off occurs because the sprinkler heads tend to deliver water 
to an area too quickly for the water to be effectively absorbed into the 
ground. In addition, water droplets from the sprinkler head systems tend 
to impinge on surrounding structures such as houses, fences, and vehicles 
for example, causing discoloration, staining, and other damage. Despite 
these limitations, sprinkler irrigation systems easily make up the 
majority of landscape irrigation systems installed today. 
Low volume surface drip irrigation devices and lines, typically emitting 
water in the range of 0.5 to 2 gallons per hour, use an extensive network 
of conduits. Emitters are attached to the conduits and are spaced apart on 
the surface of the area to be irrigated. The water drips from these 
emitters at slow rates and is mainly influenced by capillary action and 
gravity once the water enters the soil area directly around the emission 
point. Delivery of water in this manner does eliminate over spray and 
run-off, but is only practical for landscape plantings in areas not 
subject to traffic or heavy maintenance. Even in landscapes, surface drip 
irrigation is not practical for dense plantings with shallow root zones 
such as ornamental ground covers or turfs. If surface drip irrigation were 
used in traffic areas, such as lawns, the lines would have to be laid down 
12 to 18 inches apart from each other and taken up in between irrigations 
to allow the lawn to be used and maintained. This impracticality, combined 
with the detracting visual appearance of the lines placed every 12 to 18 
inches along the surface of the lawn, make surface drip irrigation totally 
unacceptable. 
Subsurface drip irrigation systems consist of low volume drip emitter 
lines, with drip emission rates ranging from 0.5 to 2 gallons per hour. 
The lines and emitters are placed beneath the soil surface in order to 
provide watering in the root zone. The lines commonly consist of extruded 
polyethylene tubes with calibrated emission drip devices either inserted 
onto or into the tube. The water is emitted at regular intervals along the 
line buried below the soil surface and is distributed by the effects of 
capillary action in the soil and gravity. The lines are typically buried 6 
to 8 inches below the soil surface and are spaced 12 to 18 inches apart in 
order to attempt to provide uniform watering to the top soil layers in 
between and above the drip lines. 
However, due to the effects of gravity combined with the capillarity of the 
soil below the drip lines, more than 50% of the water percolates below the 
drip line level and is not available to the lawn and shallow rooted 
plantings. In addition to inefficiencies, these buried lines and emission 
devices are plagued with problems of plugging due to the ingrowth of plant 
roots. State of the art solutions to this root ingrowth problem have 
consisted of using toxic chemicals impregnated within the lines or 
emission devices or injected into the irrigation water to kill the roots 
around the emission devices. Even if roots are kept out through chemical 
treatments, soil may work into the emission devices due to the low 
velocity and mass flow rate of the water exiting the emission devices and 
this soil may also plug the devices. The subsurface emitters may also be 
plugged by insects, insect eggs, and various other natural blocking 
agents. 
SUMMARY OF THE INVENTION 
It is a general object of the invention to overcome the above-described 
limitations and other problems associated with prior irrigation devices 
and methods. More particularly, it is an object of the invention to 
provide a device and method for low volume irrigation in combination with, 
or in lieu of, a standard sprinkler irrigation system. 
In order to accomplish these objects, one form of the invention includes a 
device which replaces the internal working mechanism of a typical 
sprinkler head device. The replacement device includes a manifold cap 
having one or more water distribution passages formed therein. Each water 
distribution passage is adapted to connect to a conveyance channel which 
is buried in the area to be irrigated and leads to an emission point at a 
remote location from the sprinkler head device. A flow controlling device 
is associated with each water distribution passage to control the flow 
through each water distribution passage and conveyance channel. The flow 
from the manifold can be controlled using any of the many commonly 
available state of the art devices such as, for example, throttling valves 
or restrictive orifice diaphragms which change available flow area as the 
upstream pressure changes. The manifold cap may also include a screen for 
filtering debris from the irrigation water prior to entering the water 
distribution passages. 
This preferred form of the invention is installed in a previously installed 
sprinkler irrigation system by unscrewing the internal mechanism of the 
conventional sprinkler head and attaching in its place the manifold cap 
device. Following installation in the sprinkler head, the flow from each 
individual water distribution passage or port is directed to an area 
removed from the sprinkler head location via the respective conveyance 
channel which is preferably buried below the aeration depth in the area to 
be irrigated and brought up to the surface at an emission point where 
water is to be applied to the area to be irrigated. The flow through the 
water distribution passage is controlled to a high enough flow rate to 
cause localized spread of water by exceeding the infiltration rate or 
hydraulic loading rate of the soil. Roots and thatch in the area assist 
the spread of the water around the emission points. The spread of water 
is, therefore, less effective by gravity and evenly distributed within the 
root zones. The higher flow rate through the conveyance channels also 
flushes the channels continuously during each irrigation cycle and 
minimizes plugging. 
The conveyance channels and surface emission points are preferably spread 
out in a polar array around the sprinkler head so as to effect full 
coverage of the area with efficient irrigation in the root zone. In this 
manner, the invention can easily be retro-fitted into the many previously 
installed sprinkler head irrigation systems without having to redesign the 
systems. 
In an alternate form of the invention, the manifold cap includes a pop-up 
sprinkler device and a mechanism to switch between the pop-up sprinkler 
head device or the water distribution passages, or to use both 
simultaneously. The mechanism to switch between the water distribution 
passages or sprinkler device preferably includes a plurality of valves on 
associated with each water distribution passage and a separate valve 
associated with the sprinkler head. 
In another alternate form, the invention includes a device body which is 
connected below the spray head as a replacement to the riser conduit or in 
addition to the riser conduit which provides fluid communication between 
the underlying water supplying tubing network and the sprinkler head. 
Where the device body comprises a replacement for the riser conduit, the 
device body preferably includes a series of axially aligned threaded 
connectors. Thus, the device body may be cut to a desired length leaving 
one of the threaded connectors to connect to the underlying buried tubing. 
This alternate form of the invention also preferably includes a valve for 
each water distribution passage which allows some or all of the water 
distribution passages to be closed off. 
Alternatively to a separate manifold or device body, the water distribution 
passages and flow control devices may be incorporated into a sprinkler 
head itself. The water distribution and flow control arrangement may be 
molded into the sprinkler head body or added by a suitable process to a 
previously molded sprinkler head body. In this form of the invention, the 
standard sprinkler head is simply removed and replaced with the sprinkler 
head having the water distribution passages and flow control. 
According to the method of the invention, water is supplied through a water 
supply conduit associated with a previously installed sprinkler irrigation 
system. The water is supplied through a sprinkler head connector 
associated with the water supply conduit to a manifold connected to the 
sprinkler head connector. The method also includes directing water from 
the manifold to a remote area to be irrigated through a buried conveyance 
channel having an emission end positioned generally at the surface of the 
area to be irrigated. The method includes controlling the flow through the 
conveyance channel to a rate exceeding the hydraulic loading rate of the 
area adjacent to the conveyance channel emission end. Water emitted at 
this rate produces localized run-off around the emission end and an 
extended wetting pattern around the emission end. 
The apparatus and method according to the invention provide continuous, 
efficient water distribution for turf or dense plantings. The method and 
apparatus provide a positive, mechanical means for preventing roots from 
growing into the emission devices via the subsurface conveyance channel 
and its mechanical connection to the emission device. Furthermore, the 
apparatus provides a field switchable arrangement between sprinkler and 
non-sprinkler irrigation, particularly low energy precision flood 
irrigation. The non-sprinkler form of irrigation is not be effected by 
wind, over spray, and run-off.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 illustrates a form of the invention which completely replaces a 
sprinkler type irrigation system with a non-sprinkler irrigation system, 
particularly a low flow or low energy precision flooding type irrigation 
system. The apparatus according to the invention includes a manifold 20 
which is secured to a sprinkler head body 22 with the connector 24 at the 
top of the sprinkler head body. The manifold 20 forms a cap which replaces 
the pop-up or other sprinkler mechanism which was previously secured to 
the sprinkler head top connector 24. The sprinkler head body 22 includes a 
lower threaded portion 26 which connects to a riser nipple or conduit 28. 
The riser conduit 28 connects to a "tee" 30 fitted in a water supply line 
or conduit 32. The water supply line 32, riser 28, and sprinkler head body 
22 are all buried below the soil surface S with the manifold cap 20 
preferably immediately below the soil surface or at the soil surface. 
The manifold 20 includes a plurality of water distribution passages 34 each 
having an inlet end 35 and an outlet end 36. The inlet end 35 of each 
water distribution passage 34 is exposed to the cavity 37 formed within 
the sprinkler body 22 in position to receive water supplied to the 
sprinkler body. The outlet end 36 includes a suitable connection such as a 
barb connector for connecting to a conveyance channel or tube 38. Also, a 
flow control device or means 39 is associated with each water distribution 
passage 34. The flow control device 39 serves to limit the flow through 
the passage 34 to a desired flow rate described below. In the preferred 
form of the invention shown in FIG. 1, each water distribution passage 34 
further includes a cut-off valve 40 which may be used to completely or 
partially block the flow of water through the particular water 
distribution passage. A screen 41 may be included with the manifold 20 to 
filter debris from water reaching the water distribution passages 34. 
The manifold device 20 is manufactured from any material suitable for 
irrigation components such as polycarbonate plastic, for example. The 
conveyance channels 38 may be made from polyethylene or other suitable 
flexible plastic material. The flow controlling devices may be formed from 
a rubber or silicone. The preferred flow controlling device includes a 
passage (not shown) through a flexible material. The passage reduces in 
area in response to a higher pressure on the upstream side of the device. 
The variable flow area controls the flow rate to the desired rate for a 
range of water supply pressures. 
Referring to FIGS. 1 and 2, the manifold 20 may include eight water 
distribution passages 34 to accommodate eight conveyance channels 38, for 
example. Although eight conveyance channels are shown for purposes of 
illustration, more or fewer may be used and arranged in any pattern to 
produce the desired watering pattern. In the form of the invention shown 
in FIG. 1 in which the manifold 20 completely replaces a sprinkler 
mechanism, the conveyance channels 38 are preferably arranged radially. 
Four conveyance channels 38 may extend to distant emission points 42a, 
42b, 42c, and 42d while another four conveyance channels 38 extend to 
closer emission points 43a, 43b, 43c, and 43d. Each conveyance channel 38 
is buried below the soil surface with the distal end rising to the surface 
so that irrigation water may flow from the conveyance channel to the 
surface and spread out over the surface. 
The flow rate through each conveyance channel 38 and water distribution 
passage 34 associated therewith is controlled to exceed the local 
hydraulic loading or infiltration rate in the area around the respective 
emission point. The hydraulic loading rate is effected by the nature of 
the soil, the density of plantings and roots in the root zone, and the 
nature of any thatch layer present on the surface of the soil. By 
exceeding the local hydraulic loading rate, the water exiting the 
conveyance channels 38 at the respective emission point 42a, 42b, 42c, or 
42d or 43a, 43b, 43c, or 43d spreads out around the emission point to 
produce an extended wetting pattern such as wetting patterns 46 and 47 
shown in FIG. 2. The size of the pattern depends upon the amount by which 
the flow rate exceeds the local hydraulic loading rate. For example, the 
wetting pattern 47 near the manifold may be produced with a 10 gallon per 
hour flow rate, while the patterns 46 may be produced with a 20 gallon per 
hour flow rate. Flow rates may range from 2 gallons per hour to 4 gallons 
per minute, while the most common flow rates range from 10 gallons per 
hour to 30 gallons per hour. 
FIG. 3 shows an alternative form of the invention which retains a 
conventional sprinkler capability in addition to providing a manifold 50 
for irrigation through conveyance channels. The manifold 50 forms a cap 
which is attached to a previously installed sprinkler head body 52 similar 
to the embodiment shown in FIG. 1. The manifold 50 includes one or more 
water distribution passages 52, each with a flow control device 53 and a 
valve 54. The manifold 50 shown in FIG. 3 also includes a sprinkler 
mechanism opening 55 with a sprinkler stem 56 extending therethrough. The 
sprinkler stem 56 includes a spray head 57 at its top and preferably 
includes a mechanism (not shown) incorporated in the spray head to adjust 
the spray pattern or block the spray off completely. A spring 58 
associated with the sprinkler stem 56 helps retract the stem back into the 
sprinkler head body 51 when it is not receiving irrigation water through 
the water supply conduit 59. 
FIGS. 4 and 5 show an alternate form of the invention in which the manifold 
70 comprises a ring which is secured around the body 71 of a standard 
sprinkler head. In this form of the invention, the manifold ring 70 slides 
over the sprinkler head body 71 with close tolerance leaving an annulus 
72. The annulus 72 is positioned adjacent to an opening 73 which is 
drilled other otherwise formed through the sprinkler head body 71. In this 
position, with the annulus 72 aligned with the opening 73 through the 
sprinkler head body, the manifold ring 70 is glued, chemically welded, or 
otherwise fixed in place and sealed to the sprinkler head body. 
The manifold ring 70 includes a plurality of water distribution passages 74 
similar to the embodiment shown in FIGS. 1 and 3. A flow control device 75 
and a valve 76 is associated with each water distribution passage 74. The 
outlet end of each water distribution passage includes a barb connector 77 
or other suitable connector for accepting a conveyance channel (not shown 
in FIGS. 4 and 5). In this form of the invention, the barbed outlet end 77 
of each water distribution passage 74 is directed downwardly and shielded 
by the manifold 70 to help prevent debris from entering the water 
distribution passages during the installation process. 
The form of the invention shown in FIGS. 4 and 5 replaces the previously 
installed sprinkler head (not shown) in the sprinkler head irrigation 
system. The previously installed sprinkler head is simply removed and 
replaced with the new sprinkler head body 71 having the manifold ring 70 
secured thereto. Alternatively, the previously installed sprinkler head 
may be removed and modified by the addition of the manifold ring 70 and 
then replaced into the irrigation system. 
FIGS. 6 and 7 show another alternate form of the invention which is adapted 
to be secured in a previously installed sprinkler system below a standard 
sprinkler head. The device includes a device body 80 with a lower 
connection 81 for securing the device to the water supply conduit or a 
riser connected to the water supply conduit (not shown in FIGS. 6 and 7). 
An upper connection 82 is adapted to receive a standard sprinkler head 
device (not shown). In this form of the invention, the device includes a 
single water distribution passage 83 which includes a flow control device 
84 similar to the previously illustrated embodiments. The form of the 
invention as shown in FIGS. 6 and 7 does not include a cut-off valve, but 
such a valve may be included in this alternate form of the device if 
desired. 
The device illustrated in FIGS. 6 and 7 is particularly adapted to irrigate 
deficiency areas in a sprinkler irrigation pattern. Once a deficiency area 
is identified in a sprinkler irrigation pattern, one of the sprinkler 
heads in the system may be removed temporarily and a device such as that 
shown in FIGS. 6 and 7 installed. A conveyance channel may then be 
extended with its distal end running to the center of the deficiency area. 
FIG. 8 illustrates another alternate form of the invention with particular 
application in providing supplemental irrigation to a deficiency area in a 
sprinkler system wetting pattern. In this form of the invention, the water 
distribution passage 87 is formed in a nipple 88 which is integrally 
molded or otherwise formed in the body 89 of the sprinkler head 86. A cap 
90 fits over the nipple 88 and includes the outlet end 91 of the water 
distribution passage to which a conveyance channel 92 may be connected. 
Although not show in FIG. 8, a flow control is associated with the water 
distribution passage 87 and is preferably incorporated into the cap 90. 
The cap may also include a valve similarly to the embodiment shown in FIG. 
1. Where supplemental irrigation is not required through the particular 
sprinkler head 86, the nipple 88 may include simply a sealing cap to 
prevent water from exiting through the nipple. 
The combined sprinkler/manifold device 86 is installed in a sprinkler 
system preferably adjacent to a deficiency area 93 which does not receive 
sufficient irrigation through the sprinkler associated with standard 
sprinkler heads 86. Once the deficiency area 93 is identified, the 
conveyance channel 92 may be installed with an emission point 94 generally 
in the center of the deficiency area. In operation, the sprinkler heads 86 
continue to provide irrigation in the standard sprinkler pattern and the 
deficiency area 93 is irrigated through the conveyance channel 92. 
FIG. 9 illustrates another form of the invention and FIG. 10 illustrates an 
installation for this alternate form. Referring to FIG. 9, the irrigation 
device 97 includes an upper threaded connection 98 to which a sprinkler 
head may be secured. The device 97 also includes a water distribution 
passage having a barbed outlet end 98. Although not shown in the drawing, 
the water distribution passage has associated with it a flow control and 
may also include a valve similar to those illustrated in FIG. 1. The lower 
portion of the device 97 includes a riser portion 99. The riser portion 99 
includes a plurality of axially aligned threaded connections 100. The 
riser portion 99 may thus be cut to a desired length leaving one of the 
axially aligned threaded connections 100 in position to connect to a riser 
connection 101 associated with a water supply conduit 102 (FIG. 10). 
Referring to FIG. 10, the device 97 replaces a standard riser which 
connects a standard sprinkler head 103 to the water supply conduit 102. A 
conveyance channel 104 which may be connected to the outlet end 98 of the 
water distribution passage may extend to an emission point 105 in a 
deficiency area within the sprinkler head pattern or to an area completely 
outside of the sprinkler head pattern. 
The above described preferred embodiments are intended to illustrate the 
principles of the invention, but not limit the scope of the invention. 
Various other embodiments and modifications to these embodiments may be 
made by those skilled in the art without departing from the scope of the 
invention as described. For example, although the Figures illustrate 
pop-up type sprinkler heads, a sprinkler head within the scope of the 
invention may include a pop-up spray type sprinkler, an impact sprinkler, 
a gear driven rotor sprinkler, or any other type of sprinkler device. 
Also, each embodiment of the invention may include a plurality of water 
distribution passages or a single water distribution passage.