Fluid sprinkling – spraying – and diffusing – Conduit or nozzle attached irrigation-type decelerator
Reexamination Certificate
2000-06-27
2001-10-16
Scherbel, David A. (Department: 3752)
Fluid sprinkling, spraying, and diffusing
Conduit or nozzle attached irrigation-type decelerator
C239S547000, C138S046000, C137S854000, C137S614200
Reexamination Certificate
active
06302338
ABSTRACT:
FIELD AND BACKGROUND OF THE INVENTION
The present invention relates to drip irrigation lines, and particularly to drip irrigation lines which include a plurality of emitter units secured within a water supply tube for discharging water therefrom at a low rate.
Irrigation emitters are commonly constructed with relatively large passageways to reduce the sensitivity of the emitter to clogging by particles in the irrigation water. However, such emitters may also be clogged by external particles, e.g., dirt entering the emitters via the water discharge openings. The problem is particularly acute when a drip irrigation line is emptied since this produces a vacuum within the line which tends to suck external particles into the emitter units via the water discharge openings. For this reason, special pains are frequently taken in installing a drip irrigation line to expose the water discharge openings to the air and not to the soil, but even then, there is still a large tendency of external solid particles to enter the line via the water discharge openings particularly when the line is emptied.
It is known to provide drip irrigation emitters with a one-way valve at the inlet to prevent undesirable discharge or leakage of water when the line pressure is not sufficient for drip irrigation purposes; see, for example, Mehoudar U.S. Pat. Nos. 5,279,462 and Eckstein et al 5,615,838. Such emitters utilize the membranes provided for the function of pressure-compensation also for the function of acting as a one-way valve at the inlet to prevent water discharge or leakage at unduly low line pressures. The fad that the same membrane serves both the one-way valve function, and also the pressure-compensation function, makes it difficult to design it so that it optimally serves both functions for each application.
OBJECTS AND BRIEF SUMMARY OF THE INVENTION
An object of the present invention is to provide a drip irrigation line having a one-way valve, which is independent of the flow-control passageway of the line, to produce reduced sensitivity to clogging by the entry of external particles via the water discharge openings. Another object of the present invention is to provide such drip irrigation lines with additional advantages, including the ability to save water, to operate when buried under the ground, and/or to discharge the water in the form of pulses.
According to a broad aspect of the present invention, there is provided a drip irrigation line, comprising: a water supply tube for conducting water therethrough and having a plurality of water discharge openings spaced along its length; and a plurality of emitter units secured within the water supply tube such that each emitter unit defines with the tube a flow-control passageway having an inlet port communicating with the interior of the water supply tube, and an outlet port communicating with a water discharge opening in the water supply tube, each of the emitter units including a one-way valve at one of the ports permitting water flow in the forward direction from the interior of the water supply tube towards a water discharge opening thereof, but blocks water flow in the reverse direction from the water discharge opening towards the interior of the water supply tube; characterized in that the port which includes the one-way valve comprises an opening circumscribed by a cylindrical boss projecting from the downstream side of the opening facing the water discharge outlet in the water supply tube; and in that the one-way valve includes a cap having an end wall engageable with the inner surface of the water supply tube, and a skirt of elastomeric material normally engaging the outer surface of the cylindrical boss to block water flow through the one-way valve, but deformable under water pressure to permit water flow in the forward direction.
In one described embodiment, the end wall of the cap is also made of elastomeric material and is integrally formed with the skirt; and in another described embodiment, the end wall of the cap is made of rigid material joined to the skirt of elastomeric material.
According to additional features in another described embodiment, the cylindrical boss is formed with an axial slot extending a short distance from the outer edge of the boss and completely covered by the elastomeric skirt of the cap in the normal, non-deformed condition of the skirt. More particularly, in that described preferred embodiment, the cylindrical boss is formed with a plurality of the axial slots, the slots being circumferentially spaced around the circumference of the outer edge of the boss.
In some described embodiments, the one-way valve is located at the inlet port, and in another described embodiment, it is located at the outlet port.
A drip irrigation line constructed in accordance with the foregoing features will thus prevent external dirt particles from being drawn into the emitter units when the water supply tube is emptied despite the vacuum produced in the water supply tube. Also, when the line including such units is initially filled with water, or when the pressure in the line otherwise is below the predetermined minimum, the one-way valve remains closed, thereby preventing a discharge of the water under such low pressure conditions and producing significant savings in the water. Moreover, during non-operating conditions of the emitter lines, the outlets being thus blocked prevent the entry not only of solid particles, but also of air and moisture which can promote the growth of organisms within the emitter lines. These advantages permit the emitter lines to be buried in the ground. A further advantage is that such emitter lines can also be operated to output pulses, rather than a continuous trickle flow.
Since the one-way valve provided by this construction is independent of the structure of the flow-control passageway in the drip irrigation line, both the one-way valve and the flow-control passageway can each be designed for optimum performance of one without affecting the performance of the other, for each particular application.
Further features and advantage of the invention will be apparent from the description below.
REFERENCES:
patent: 3685735 (1972-08-01), Foster
patent: 4148438 (1979-04-01), Moen
patent: 4502631 (1985-03-01), Christen
patent: 4573640 (1986-03-01), Mehoudar
patent: 4687143 (1987-08-01), Gorney et al.
patent: 5183208 (1993-02-01), Cohen
patent: 5279462 (1994-01-01), Mehoudar
patent: 5400973 (1995-03-01), Cohen
patent: 5609303 (1997-03-01), Cohen
patent: 5615838 (1997-04-01), Eckstein et al.
patent: 5628462 (1997-05-01), Miller
patent: 6027048 (2000-02-01), Mehoudar
Nguyen Dinh Q.
Scherbel David A.
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