Fluid sprinkling – spraying – and diffusing – Conduit or nozzle attached irrigation-type decelerator
Reexamination Certificate
2000-02-10
2001-03-27
Morris, Lesley D. (Department: 3752)
Fluid sprinkling, spraying, and diffusing
Conduit or nozzle attached irrigation-type decelerator
C239S533100, C239S533130, C239S547000, C239S571000, C138S042000
Reexamination Certificate
active
06206305
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an improved irrigation emitter unit for use in a drip irrigation system. The invention is specifically applicable to such systems wherein the emitter units are integrally bonded at spaced-apart intervals to the inner surface of a conduit adjacent to outlet apertures in the conduit, so that an irrigation flow through the conduit results in a drip rate irrigation output from the individual emitter units via the outlets.
BACKGROUND OF THE INVENTION
Such drip irrigation systems and, in particular, emitter units for use therewith, have been known for some time. They involve the provision in the emitter of an elongated, flow-restricting flowpath through which water passes from the conduit so as to emerge from the conduit outlet as a substantially pressureless drip.
The construction and provision of this flow-restricting flowpath has in general fallen into two main categories, namely:
a) where the flowpath is entirely defined within an emitter housing; and
b) where the flowpath is defined between the emitter housing and the surface of the conduit to which the housing, is bonded.
The present invention is specifically related to the first of these categories, i.e. where the flowpath is defined within the housing. Furthermore, the invention preferably relates to such an emitter unit which is provided with flow control means, e.g., differential pressure control means, designed to ensure that the output rate from the emitter is substantially independent of variations in the pressure of the irrigation supply flow to the emitter unit.
Such a drip irrigation system and, in particular, irrigation emitter units for use therewith, have been disclosed in our earlier U.S. Pat. No. 4,210,287 (hereinafter “the '287 patent”). The '287 patent discloses an emitter unit provided with a resiliently flexible membrane which is releasably retained within a body member so as to serve a double function, namely, on the one hand, whilst being exposed to the irrigation flow pressure in the conduit to serve in exercising differential pressure control, and, on the other hand, to define, with respect to a flow restricting groove formed in the body member, a flow-restricting flowpath.
There have also been previous proposals for enclosing the emitter unit in a housing. These proposals have not included adequate solutions, if at all, in connection with problems which arise regarding the possible assembly of the constituent elements of the housing.
Particular problems clearly arise where, as in the case of emitter units the subject of the present invention, relatively long, elongated emitter units are required and means have to be provided for the retention together of the constituent pieces of the container prior to its bonding to the conduit, especially when the container is formed of relatively pliable plastic material (e.g. polyethylene) so as to facilitate its ready bonding to the conduit.
It is therefore an object of the present invention to provide a new and improved irrigation emitter unit for use in drip irrigation systems, wherein the above-referred-to requirement is substantially achieved.
BRIEF SUMMARY OF THE INVENTION
According to the present invention, there is provided an emitter unit adapted to be integrally bonded to an internal surface of a conduit, comprising an elongated housing, a housing inlet adapted to communicate with an interior of said conduit; a housing outlet adapted to communicate with a conduit outlet; an elongated, flow-restricting flowpath formed in said housing; a flowpath inlet communicating with said housing inlet; a flowpath outlet communicating with said housing outlets; a resiliently flexible membrane mounted in said housing; said housing being of closed box-like shape and being constituted by an elongated receiving member and a correspondingly elongated cover member; and projection and recess interengaging means formed along the lengths of elongated rim portions of said members and directed substantially transversely to longitudinal axes of said members such that projection means of one member are adapted to form a close pressure fit within corresponding recess means of the other member.
The pressure fitting together of interengaging means located along the lengths of the rims of the constituent members of the housing ensures effective retention together of these members after their assembly together and effectively prevents their coming apart prior to the bonding of the housing to the conduit. This is of particular importance seeing that, on the one hand, the emitter units have to be stored after assembly and consequently subjected to mechanical handling during the bonding procedure and, on the other hand, the enclosed membrane has to be retained in the housing under a certain degree of resilient pressure.
By virtue of the possibility to provide relatively elongated emitter units of secure, box-like construction in accordance with the present invention, it is possible to achieve certain further additional advantages, among which may be mentioned
(i) the provision of a plurality of superimposed interconnecting flow restricting flowpaths respectively separated by the membrane or additional membranes;
(ii) the incorporation in the emitter unit of an effective non-return valve structure; and
(iii) the provision of extended filtering arrangements.
Preferably, the emitter unit is provided with differential pressure control means, in which case there is formed in the housing a recess having dimensions substantially extended as compared with the width of the flowpath, with a recess outlet formed in a base of the recess, a rim of the recess having an area substantially greater than the area of the recess outlet, a first surface of the membrane adapted to be exposed to fluid inflow pressure; a second and opposite surface of said membrane being juxtaposed to said rim and adapted to be pressed against said rim under said inflow pressure; and so as to define with said recess an outlet control chamber; the arrangement being such that when said fluid inflow pressure exceeds the fluid pressure in said outlet control chamber by a predetermined amount, the membrane flexes towards said recess outlet so as to define with the recess outlet a restricted outflow path.
Thus, there are preferably formed during the relatively simple molding of the constituent members of the housing, appropriate flow-restricting elongated grooves together with the outlet control chamber recess, these grooves and recess, together with the interposed membrane, defining the flow-restricting flowpaths and the outlet control chamber.
By virtue of the provision of the box-like housing, it is possible to provide, in the housing, in accordance with one aspect of the present invention, one or more elongated inflow channels located preferably adjacent one or both elongated edges of one of the constituent members of the housing. These channels communicate with the housing inlet and are exposed to the interior of the conduit.
These channels, which are also formed during the molding of one or other of the constituent members of the housing, are partially covered, thus facilitating the provision of a relatively restricted filtering type inlet into the channels and at the same time allowing for the provision of relatively widely dimensioned channels.
The channels are provided with an array of filter baffles located along the length thereof. In this way, irrigation flow passes into the emitter unit, alone one or more extended, open inflow channels provided with filtering means, and in this wave the inflow channel itself can be of relatively wide dimensions, thereby again restricting the dangers of blockage.
REFERENCES:
patent: 4105162 (1978-08-01), Drori
patent: 4210287 (1980-07-01), Mehouder
patent: 4392616 (1983-07-01), Olson
patent: 4728042 (1988-03-01), Gorney et al.
patent: 5203503 (1993-04-01), Cohen
patent: 5294058 (1994-03-01), Einav
patent: 5324371 (1994-06-01), Mehoudar
patent: 5400973 (1995-03-01), Cohen
patent: 5586727 (1996-12-01), Shekalim
patent: 5609303 (1997-
Ganey Steven J.
Helfgott & Karas P.C.
Hydroplan Engineering Ltd.
Morris Lesley D.
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