DRIP IRRIGATION EMITTER
TECHNICAL FIELD
[001] The present disclosure relates to drip irrigation emitters that are used to
control the provision of liquid to plants.
BACKGROUND
[002] Such drip emitters are normally coupled to an irrigation pipe and are
provided with an inlet, an outlet and a flow-restricting path therebetween. Liquid
passing from the pipe via the inlet into the emitter; traverses through the flow-
restricting path to be released at the outlet of the emitter at a relatively low discharge
pressure generally equal to about zero.
[003] US Patent No. 6,250,571, the disclosure of which is incorporated herein
by reference, describes a drip irrigation emitter having a non-regulating labyrinth
that functions to reduce pressure of water entering the emitter before it reaches a
regulating labyrinth. A modification of the emitter has an opening that serves as an
outlet from the non-regulating labyrinth and an inlet to the regulating labyrinth.
This opening is covered by a membrane that functions as a one-way valve
permitting flow of water only from the non-regulating labyrinth to the regulating
labyrinth.
[004] US Patent No. 5,111,996, the disclosure of which is incorporated herein
by reference, describes an emitter having valves that are used to control the length
of a fluid flow limiting passageway. The passageway is divided into sections and as
the pressure in the pipe increases beyond predetermined values, valves that are
located along the passageway close to force fluid to flow through additional sections
of the passageway.
SUMMARY
[005] The following embodiment and aspects thereof are described and
illustrated in conjunction with systems, tools and methods which are meant to be
exemplary and illustrative, not limiting in scope.
[006] In an embodiment, a drip irrigation emitter comprises an inlet through
which liquid enters the emitter from an irrigation pipe, an outlet communicating
with the outside environment, a flow path extending between the inlet and outlet,
said flow path comprising pressure reducing flow parts, a venting zone and a
regulating zone for regulating the flow of liquid exiting the emitter via the outlet, the
emitter further comprising a duct that is adapted to provide fluid communicating
between the venting zone and the outside environment above a threshold pressure of
liquid in the pipe.
[007] Optionally, the venting zone is located between the pressure reducing
parts and the regulating zone.
[008] Optionally, a seal of the emitter may prevent fluid communication via the
duct below the threshold pressure and allow fluid communication via the duct above
the threshold pressure.
[009] Optionally, the duct comprises pressure reducing parts downstream of the
seal.
[010] In another embodiment, a drip irrigation emitter for receiving liquid
flowing in an irrigation pipe, at an' inlet pressure and emitting the liquid out of the
emitter at an outlet pressure lower than the inlet pressure, the emitter comprising a
flow path through which the liquid flows in the emitter, wherein below a threshold
pressure of liquid in the pipe the emitter is adapted to emit a regulated flow of liquid
out of the emitter, and wherein above the threshold pressure of liquid in the pipe the
emitter is adapted to at least partially emit a substantially non-regulated flow of
liquid out of the emitter.
[011] Optionally, the flow path comprises a regulating zone that is adapted to
regulate the flow of liquid out of the emitter below the threshold pressure of liquid
in the pipe, and wherein above the threshold pressure of liquid in the pipe the flow
of liquid out of the emitter is substantially not affected by the regulating zone.
[012] In addition to the exemplary aspects and embodiment described above,
further aspects and embodiments will become apparent by reference to the figures
and by study of the following detailed descriptions.
BRIEF DESCRIPTION OF THE FIGURES
[013] Exemplary embodiments are illustrated in referenced figures. It is
intended that the embodiments and figures disclosed herein are to be considered
illustrative, rather than restrictive. The disclosure, however, both as to organization
and method of operation, together with objects, features, and advantages thereof,
may best be understood by reference to the following detailed description when read
with the accompanying figures, in which:
[014] Fig. 1 shows a perspective top view of a drip emitter in accordance with
the present disclosure;
[015] Fig. 2 shows an exploded view of the drip emitter of Fig. 1;
[016] Fig. 3 shows the drip emitter of Fig. 1 with a first embodiment of a valve
thereof being shown in an exploded form;
[017] Fig. 4 shows the drip emitter of Fig. 1 with a second embodiment of the
valve being shown in an exploded form; and
[018] Figs. 5Aand 5B show cross sectional views of the drip emitter of Fig. 1.
[019] It will be appreciated that for simplicity and clarity of illustration,
elements shown in the figures have not necessarily been drawn to scale. For
example, the dimensions of some of the elements may be exaggerated relative to
other elements for clarity. Further, where considered appropriate, reference
numerals may be repeated within the figures to indicate like elements.
DETAILED DESCRIPTION
[020] Attention is first drawn to Figs. 1 and 2. A drip irrigation emitter 10 has a
body 12, a cover 14 and a flexible diaphragm 16 that is pressed therebetween. A
flow path 20 of the emitter 10 has a regulating zone 18 in an optional form of a
chamber or cavity that is formed on a lower side of the body 12. Pressure reducing
parts 22 of the flow path 20 are formed along a portion of the flow path 20 that
empties downstream into the regulating zone 18. The pressure reducing parts 22,
which in this example are in the form of baffle teeth that project into the flow path
20, exhibit a relatively high resistance to liquid flow per unit length and as a result
the pressure of liquid entering the emitter 10 at a relatively high inlet pressure drops
rapidly as liquid flows therethrough.
[021] The body 12 of the emitter 10 has in addition a recess 24 formed on an
upper side thereof that is bound by a peripheral wall 26. An outlet 28 of the emitter
10 that extends through the body 12 communicates between the regulating zone 18
and the recess 24. In an embodiment, the emitter 10 is adapted to attach at the
body's upper side to an irrigation pipe (not shown) with a portion of the pipe
overlying the recess 24. An aperture, for example, formed in that portion of the pipe
(not shown) provides fluid communication between the recess 24, and thereby the
emitter 10, and the outside environment.
[022] The cover 14 has upper and lower sides; and an inlet 30 in an optional
form of an elongated channel opens out to the upper and lower sides of the cover 14.
Filter ribs forming inlet gaps therebetween are located along the inlet 30 for filtering
liquid entering the emitter 10. It should be noted that directional terms appearing
throughout the specification and claims, e.g. "forward", "rear", "up", "down" etc.,
(and derivatives thereof) are for illustrative purposes only, and are not intended to
limit the scope of the appended claims. In addition it is noted that the directional
terms "down", "below" and "lower" (and derivatives thereof) define identical
directions.
[023] Attention is additionally drawn to Fig. 3. The emitter 10 has a valve 32
in accordance with a first embodiment of the present disclosure that includes a seal
34 in an optional form of a flexible diaphragm, a bracket 36 and a duct 38. The duct
38 has a first part 40 that extends between the upper and lower sides of the body 12
and provides fluid communication between a venting zone 42 (Fig. 2) of the flow
path 20 that is located between the regulating zone 18 and pressure reducing parts
22; and a concave hub 44 of the duct 38 that is formed in the recess 24. A raised rim
46 of the valve 32 circumscribes the duct's first part 40 where it opens into the hub
44 and a raised annular support 48 is formed in the hub 44 spaced from the rim 46.
A second part 50 of the duct 38 substantially free of pressure reducing obstructions
is formed in the recess 24 and communicates with the hub 44 and with the space
between the rim 46 and support 48.
[024] Attention is drawn to Figs. 1, 5A and 5B. The seal 34 is'located in the
hub 44 with its periphery resting upon the support 48 and a more central circular
portion thereof being seated against the rim 46. The bracket 36 has an opening 52
that is located above a portion of the seal 34 thereby pressing the seal 34 to seat
against the rim 46 to substantially seal the duct 38 against ingress and egress of
liquid. The upper side of the seal 34 is in communication with the recess 24 and
thereby with the outside environment and at least a portion of the lower side of the
seal 34 that is bound by the rim 46 is in communication with the venting zone 42.
The bracket 36 also overlies the hub 44 of the duct 38 and a portion of duct's second
part 50 thus forming a closed roofed channel at the duct's second part 50 that opens
out into the recess 24 to communicate with the outside environment.
[025] Attention is drawn only to Fig. 5A. Up to a given pressure threshold in
the pipe PT, liquid indicated by arrows 54 that entered the emitter 10 from the
irrigation pipe (not shown) via the inlet 30 flows in the flow path 20 along a lower
side the diaphragm 16 facing the cover 14 and then enters the body 12 to flow via
the pressure reducing parts 22 and venting zone 42 into the regulating zone 18. The
pressure of the liquid outside of the emitter 10 and inside the pipe is transmitted via
the inlet 30 to a portion of the diaphragm 16 that is located below the regulating
zone 18. This pressure is illustrated by short arrows 56.
[026] An increase of liquid pressure in the pipe may cause displacement of that
portion of the diaphragm 16 into the regulating zone 18. Resistance to flow of
liquid into the regulating zone 18 of the flow path 20 and from the regulating zone
18 via the outlet 28 to the emitter's recess 24 and the outside environment is a
function of this displacement. As the displacement of the diaphragm 16 into the
regulating zone 18 is increased, this resistance is increased. As a result, the portion
of the diaphragm 16 that is located below the regulating zone 18 operates to regulate
flow of liquid from the irrigation pipe through the emitter 10 and the flow rate of
liquid exiting the emitter 10 is substantially independent of inlet pressure for a given
pressure range for which the emitter 10 is designed to operate. Notably other
methods of regulating the flow of liquid in the regulating zone 18 may be used in
accordance with some embodiments the present disclosure.
[027] Attention is now drawn to Fig. 5B. As pressure of the liquid in the pipe
exceeds the predetermined threshold level PT, a pressure differential develops
between the lower side of the seal 34 that is exposed to the venting zone 42 and its
upper side that communicates with the outside environment. This stretches the seal
34 to unseat from the rim 46 and let liquid indicated by arrow 58 exit the emitter 10
via the duct 38.
[028] In a drip emitter 10 with a valve 32 in accordance with the first
embodiment (Fig. 3), the pressure of liquid in the venting zone 42 drops as the seal
34 lifts off the rim 46 to a level substantially equal to that of the outside
environment. This may be explained as a result of a rise in the flow rate of liquid
passing through the flow path 20 that results in an increase of pressure drop over the
flow path 20. In some embodiments, this may result in the pressure on both sides of
seal 34 being substantially the same which causes the seal to contract back towards
the rim 46 and re-seal the duct 38 to cease the flow of liquid exiting the duct 38.
[029] Under the assumption that liquid pressure in the pipe did not change then
the cessation in flow out of the emitter 10 via the duct 38 is only momentary since
the pressure differential that caused seal 34 to lift off the rim 46 is reestablished. In
general, this "vibration" cycle of sealing and unsealing of the duct 38 may repeat,
causing the emitter 10 to repeatedly emit pulses of liquid via the duct 38. Such
pulses may form a cleaning process in which foreign matter such as grit or the like
that may have accumulated for example in the emitter's flow path 20 is urged to exit
the emitter 10 via the duct 38.
[030] Attention is additionally drawn to Fig. 4 showing a drip emitter 10
having a valve 60 in accordance with a second embodiment of the present
disclosure. The structure of the valve's second embodiment 60 is generally similar
to that of the first embodiment 32 but with the addition of pressure reducing parts or
obstructions 62 that are located downstream of the seal 34 optionally in the second
part 50 of the duct 38.
[031] As in the first embodiment, pressure of liquid in the pipe exceeding the
predetermined threshold level PT, causes a pressure differential between the lower
side of the seal 34 exposed to the venting zone 42 and the upper side of the seal 34
communicating with the outside environment that stretches the seal 34 to unseat
from the rim 46 and let liquid exit the emitter 10 via the duct 38. The liquid lifting
the seal 34 flows via the pressure reducing obstructions 62 and then exits the duct 38
to communicate with the outside environment. Liquid pressure PU upstream of the
pressure reducing obstructions 62 is substantially equal to the liquid pressure below
the seal 34. In some embodiments, the pressure of liquid in the pipeis such that the
resulting pressure PU below the seal 34 keeps the seal 34 lifted off the rim 46 to
maintain a continuous flow of liquid exiting the emitter 10 via the duct 38.
[032] Notably, such a liquid flow that optionally bypasses the regulating zone
18 in emitters 10 that incorporate one of the valves 32, 60; exhibits a non-regulated
flow rate that substantially depends on the liquid pressure in the pipe so that a rise of
liquid pressure in the pipe will result in a rise in the flow rate of liquid exiting the
emitter 10 via the duct 38. In an emitter incorporating valve 60, the pressure of
liquid in the pipe that is sufficient to maintain the continuous flow of liquid via the
duct 38 is determined for example by dimensions of the rim 46 and elasticity and
dimensions of the diaphragm 16. Variations in, inter alia, those dimensions may
result in that pressure of liquid in the pipe being smaller, larger or equal to the
predetermined threshold level PT.
[033] In the description and claims of the present application, each of the verbs,
"comprise" "include" and "have", and conjugates thereof, are used to indicate that
the object or objects of the verb are not necessarily a complete listing of members,
components, elements or parts of the subject or subjects of the verb.
[034] Although the present embodiment has been described to a certain degree
of particularity, it should be understood that various alterations and modifications
could be made without departing from the scope of the disclosure as hereinafter
claimed.
We Claim:
1. A drip irrigation emitter comprising:
an inlet through which liquid enters the emitter from an irrigation pipe,
an outlet communicating with the outside environment,
a flow path extending between the inlet and outlet, said flow path comprising
pressure reducing flow parts, a venting zone and a regulating zone for regulating the
flow of liquid exiting the emitter via the outlet,
the emitter further comprising a duct that is adapted to provide fluid
communicating between the venting zone and the outside environment above a
threshold pressure of liquid in the pipe.
2. The drip irrigation emitter according to claim 1, wherein the venting zone is
located between the pressure reducing parts and the regulating zone.
3. The drip irrigation emitter according to claim 1, comprising a seal for
preventing fluid communication via the duct below the threshold pressure and
allowing fluid communication via the duct above the threshold pressure.
4. The drip irrigation emitter according to claim 3, wherein the duct comprises
pressure reducing parts downstream of the seal.
5. A drip irrigation emitter for receiving liquid flowing in an irrigation pipe at an
inlet pressure and emitting the liquid out of the emitter at an outlet pressure lower
than the inlet pressure,
the emitter comprising a flow path through which the liquid flows in the
emitter, wherein
below a threshold pressure of liquid in the pipe the emitter is adapted to emit a
regulated flow of liquid out of the emitter, and wherein above the threshold pressure
of liquid in the pipe the emitter is adapted to at least partially emit a substantially
non-regulated flow of liquid out of the emitter.
6. The drip irrigation emitter according to claim 5, wherein the flow path
comprises a regulating zone that is adapted to regulate the flow of liquid out of the
emitter below the threshold pressure of liquid in the pipe, and wherein above the
threshold pressure of liquid in the pipe the flow of liquid out of the emitter is
substantially not affected by the regulating zone.