Abstract:
A flow-regulating drip emitter, comprising a base that includes an inlet connector configured for connection to an upstream line with a water source; and a cover attached to the base, the cover including an outlet connector configured for connection to a downstream line. At least one of the cover or the base defines at least a first labyrinth passageway having a first resistance to water flow and a second labyrinth passageway having a second resistance to water flow different from the first resistance to water flow; and further wherein the base and the cover are structured so that movement of the cover in relation to the base connects the inlet connector to the outlet connector via only the first labyrinth passageway, and wherein further movement of the cover in relation to the base connects the inlet connector to the outlet connector via only the second labyrinth passageway.

Description:
BACKGROUND 
     Drip irrigation systems have come into widespread use in the agricultural area. Drip irrigation systems supply water at a slow, controlled rate to the root zone of the particular plants being irrigated. Typically, drip irrigation is accomplished by providing a low volume water outlet at each plant that permits a limited dripping of water directly to the root zone of the particular plant. Because evaporation, runoff, overwatering, and watering beyond the root zone are eliminated, substantial water and nutrient savings are realized. In addition, drip irrigation reduces contaminants to the water table by enabling the farmer to supply only enough water and fertilizer to reach the plants, reducing excess water that would run off and contaminate the water table below. 
     Drip irrigation may be supplied by hoses having drip emitters built into the hose at manufacture. These are configured to cause a reduction in water pressure between the water in the hose, and water at an outlet of the emitter. Other systems have been developed in which a user may insert separately manufactured drip emitters into the hose at spaces that are more suited to the local environment and needs for irrigation. However, as the water travels along the hose away from the water source, the pressure of the water decreases. Thus, the water pressure at the beginning of the hose (near the water source) is greater than that at the far end of the hose. Because the drip rate of an emitter is a function of the water pressure, the drip rate at the beginning of the hose may tend to be greater than at the end of the hose. Other field conditions, such as elevation, also affect the pressure, and thus the drip rate, along the length of the hose. However, it is often desirable to have a relatively uniform drip rate along the length of the hose. Moreover, other varying field conditions, such as soil type and drainage, create a need to have different drip rates throughout the field to compensate for the different field conditions. 
     Thus there is a need in the field of drip irrigation for a versatile system that a user may adapt to the changing needs of the environment, and to the location of the emitter along the length of a hose, to create a desired drip flow profile. The present invention addresses these and other needs. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to an adjustable drip emitter comprising a base that includes an outlet connector configured for connection to a downstream line; and a cover attached to the base, the cover including an inlet connector configured for connection to an upstream line with a water source. At least one of the cover or the base defines a first labyrinth passageway having a first resistance to water flow and a second labyrinth passageway having a second resistance to water flow different from the first resistance to water flow. The base and the cover are structured so that movement of the cover in relation to the base connects the inlet connector to the outlet connector via only the first labyrinth passageway, and wherein further movement of the cover in relation to the base connects the inlet connector to the outlet connector via only the second labyrinth passageway. In some embodiments, the first labyrinth passageway defines a first width and the second labyrinth passageway defines a second width, and wherein the first width is narrower than the second width. In some embodiments, the cover is structured in relation to the base so that, when the cover is attached to the base, the cover is capable of rotational movement in relation to the base. In some embodiments each of the first labyrinth passageway and the second labyrinth passageway follow a tortuous path that has a generally circular shape. In some embodiments the emitter further includes a third labyrinth passageway. In yet further embodiments, yet further movement of the cover in relation to the base connects the inlet connector to the outlet connector via only the third labyrinth passageway. 
     In further embodiments, the invention is a flow-regulating drip emitter, comprising a base that includes an outlet connector configured for connection to a downstream line, and a cover attached to the base, the cover including an inlet connector configured for connection to an upstream line with a water source. Also provided is a first means for reducing water pressure between the inlet connector and the outlet connector, and a second means for reducing water pressure between the inlet connector and the outlet connector, wherein the first means for reducing water pressure is configured to reduce water pressure to a greater degree than the second means for reducing water pressure. Further provided is a means for switching water flow through the drip emitter whereby, under a first switch setting the first means for reducing pressure receives no water flow and the second means for reducing pressure receives water flow, and under a second switch setting the second means for reducing pressure receives no water flow and the first means for reducing pressure receives water flow. In some embodiments, the means for switching includes a hollow hub protruding along a central axis of the cover, the hub having a slot and being configured so that rotation of the cover in relation to the base causes water flow to switch between the first means for reducing water pressure and the second means for reducing water pressure. 
     In yet further embodiments, the invention is a method for reducing water pressure between an inlet connection and an outlet connection of a drip-emitter, the method comprising, providing a housing that comprises a first labyrinth passageway having a first resistance to water flow and a second labyrinth passageway having a second resistance to water flow, the first resistance being greater than the second resistance. The inlet connection is inserted into a water line whereby water flows through the housing. Water flow is permitted through the first labyrinth passageway. This step is followed by switching off water flow through the first labyrinth passageway and this is followed again by switching on water flow through the second labyrinth passageway. In some embodiments, switching off water flow through the first labyrinth passageway includes rotating the first labyrinth passageway in relation to the inlet connection, and further, switching on water flow through the second labyrinth passageway includes rotating the second labyrinth passageway in relation to the inlet connection. 
     These and other features and advantages of the present invention will be better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a drip emitter having features of the present invention; 
         FIG. 2  is a side elevational view of the drip emitter shown in  FIG. 1 ; 
         FIG. 3  is a perspective view, obliquely from above, of a lower base portion of the drip emitter shown in  FIG. 1 ; 
         FIG. 4  is a perspective view, obliquely from below, of an upper cover portion of the drip emitter shown in  FIG. 1 ; 
         FIG. 5  is the view of the portion seen in  FIG. 4 , showing an additional plug element of the invention; 
         FIG. 6  is a sectional view taken vertically through the center of the emitter seen in  FIG. 1 , and substantially along the line C-C in  FIG. 2 , and viewed in the direction of the arrows associated with line C-C; and 
         FIG. 7  is a perspective view of the drip emitter of  FIG. 1 , seen from a bottom side if the drip emitter. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention is directed to a drip irrigation emitter which, when a plurality of such emitters are inserted sequentially into hosing will provide drip irrigation at periodic intervals over a length of hose. Each individual drip emitter of the present invention has the capacity to allow a user to set a flow rate for a given pressure, the flow rate chosen between a plurality of possible flow rates. 
     In one embodiment, the invention is directed to an adjustable emitter comprising separable and attachable elements. When these emitters are connected to an elongate hose, a user may adjust the drip settings to provide a desired flow outcome in any given landscape. 
     As seen in  FIG. 1 , a drip emitter  10  having features of the invention is shown. In some embodiments, the drip emitter comprises a cover  12  having a circular profile and a base  14  having a circular profile. The cover is configured to be connected to the base. To this end, in some embodiments, the cover is provided with three bent fingers  18  situated at evenly spaced intervals along a circumference on the circular profile of the cover. Three slots  20  are provided on the base, the slots being discontinuities in a circular flange  24  that surrounds the base. The slots are also spaced along a circumference of the circular profile of the base, in mating locations so that, when the cover is brought into contact with the base, the fingers  18  may pass through the slots  20 . Then, the cover may be rotated in relation to the base, and the fingers pass underneath a lower surface of the flange  24 . The result is that the cover  12  is attached to the base  14 , while maintaining the ability to rotate in relation to the base. 
     As seen in  FIGS. 1 and 2 , when the cover  12  is attached to the base  14 , the emitter  10  comprises a compact unit, which forms a housing. This unit includes an internal passage for water to flow through the emitter, a passage that is sealed from leakage but which presents an inflow port and an outflow port. As will be seen in more detail below, the internal passage of the emitter shown in this embodiment actually includes three potential passages that are individually selectable by a user of the emitter. The number of passageways may be two, or more than two, such as three or four. 
     Specifically, the base  14  comprises a hollow outlet connector  26  extending downwardly along a central axis B-B of the base. The outlet connector defines an outlet bore  28  ( FIG. 6 ) which defines a port  30  opening into a center point of an upper surface  32  of the base as seen in  FIG. 3 . The spike may include a barbed tip  34  for connection to a downstream line (not shown), according to known methodology. The downstream line extends to the point of drip emission. 
       FIG. 3  is an oblique downward view onto an upper surface  32  of the base  14 . As seen in  FIG. 3  three labyrinth passageways  36   a ,  36   b ,  36   c  are cut or molded into the upper surface  32 . Each one is designed so that water may flow from one end of the labyrinth to the other end, and thereby to undergo turbulent flow which will cause resistance to flow, and a consequent reduction in water pressure over the course of the labyrinth. However, as will be described more fully below, the emitter is configured so that only one labyrinth can receive water flow at any time, as elected by the user. As may be seen in  FIG. 3 , in some embodiments, the labyrinths may each follow the same general tortuous path of approximately equal length, but the first labyrinth  36   a  is narrower than the second  36   b  which in turn is narrower than the third  36   c . The tortuous paths are configured to reduce the flow rate of the water through the emitter, and thereby effectively to reduce the water pressure at an output port of the emitter in relation to the water pressure at an inlet port. It will be appreciated by those skilled in the art that the narrower the labyrinth through which the water is forced to flow, the greater the resistance to water flow, and the greater the pressure reduction will be across the emitter. The general use of a labyrinth passageway to reduce pressure in flowing water is known, and described in the prior art. 
       FIG. 4  shows an oblique upward view onto a lower surface  38  of the cover  12 . The lower surface  38  defines a downwardly protruding hub  40  that is shaped to fit into the port  30  of the upper surface  32  of the base  14  when the cover  12  and base  14  are connected. The hub  40  is shaped to include a slot  42  that faces radially outwardly. This configuration has the result that, when the cover  12  is connected with the base  14  as seen in  FIG. 1 , the cover  12  may be rotated in relation to the base  14  so that the slot  42  faces, in a registration position, a selected one of ending points  44   a ,  44   b ,  44   c  of one of the labyrinths. This may be envisaged with reference to  FIG. 3  together with  FIG. 4 . 
       FIG. 4  also shows that a generally circular cylindrical reservoir  44  may be cut or molded into the upper surface  38  of the cover  12 . The reservoir defines an inlet port  46  in the center of the reservoir roof  52 .  FIG. 6  shows that, on an upper surface of the cover  12 , a hollow inlet connector  48  may extend upwardly and includes an inlet bore  49  extending along an axis A-A that is offset from the central axis B-B of the emitter. The inlet connector  48  may include a spiked barb  47  to facilitate connection to a hose (not shown) carrying the water supply for the emitter. The inlet port  46  ( FIG. 4 ) is configured to receive water entering the emitter  10  from the inlet bore  49  of the inlet connector  48 . 
       FIG. 5  shows the same view of the cover  12  as  FIG. 4 , but additionally shows how a circular rubber or polymer plug  16 , or diaphragm, is positioned within the reservoir  44 . Ribs  50  molded radially into the roof  52  of the reservoir  44  prevent the plug  16  from advancing all the way into the reservoir, so that a gap  51  (as seen in  FIG. 6 ) must exist between the roof  52  of the reservoir and the plug  16 . 
     Furthermore,  FIGS. 4 and 5  show that the reservoir  44  is not exactly circular all the way round its perimeter. Along an arc length of about 10 degrees of the circumference, the radius of the reservoir increases (compared to the balance of the circumference radius) to provide a slot in the wall of the reservoir which may operate as an upper gate  54  whose function is described below. 
       FIG. 3  shows that the labyrinths  36   a ,  36   b ,  36   c  each extend along a generally circular (and tortuous) path, but that at the starting points of each labyrinth, the path increases its circular radius along an arc length of about 30 degrees. These starting points form lower gates  56   a ,  56   b ,  56   c  whose function will be explained further below. The lower gates are configured so that, when the cover  12  and base  14  are connected to each other, they will sequentially register with the upper gate  54  if the cover is rotated in relation to the base. Furthermore, the cover and base are configured so that, when the upper gate  54  is in registration with each one of the lower gates, then also, the slot  42  will be aligned with each respective one of the ending points  44   a ,  44   b , or  44   c  of one of the labyrinths. When thus registered, water may pass from the upper gate  54  into one of the lower gates, and thence along the labyrinth. But, as one skilled in the art will appreciate, the plug  16  which is under pressure from the water in the gap  51 , will prevent water flow from the gap  51  in the reservoir into any other point along a labyrinth other than a lower gate. Thus, when the emitter  10  is used, the user will rotate the cover  12  in relation to the base  14  until a series of tactile clicks, caused by detents (not shown) passing across each other, warn the user that registration has been achieved between the slot  42  on the hub  40  and a chosen end point  44   a ,  44   b ,  44   c  of one of the labyrinths  36   a ,  36   b ,  36   c . (and also, that registration has been achieved between the upper gate and the respective lower gate.) When the correctly selected labyrinth is in registration with the slot  42 , the user may forcefully insert the barbed tip  47  of the inlet connector  48  into a hose. Water from the hose will then be able to flow through the bore  49  of the inlet connector  48 , through the port  46 , and into the gap  51  of the reservoir. One skilled in the art will appreciate that the water pressure in the gap will force the plug to seat comfortably on the outline of the respective labyrinth, thus sealing the roof of the labyrinth. The water then will flow through the upper gate  54  into a respective lower gate  56   a ,  56   b , or  56   c , and thence into the selected labyrinth where it will be slowed down by turbulence (and thus will lose pressure), until the water reaches the selected end point  44   a ,  44   b , or  44   c  of the respective labyrinth. 
     It will also be appreciated by one of skill in the art that the effect of water pressure in the gap  51  may apply pressure to the plug  16  so that there is a slight throttling effect on water in the labyrinth. Therefore, under high water pressure from the hose (not shown) a choking effect may reduce water flow slightly, and under low water pressure, a releasing effect may increase water flow slightly. This throttling effect is an advantage in the emitter  10  in that it tends to even out water flow through the emitter even if water pressure in the hose (not shown) varies. 
     As noted above, when there is registration between the slot  42  and a selected labyrinth, there will also be registration between the lower gate of the selected labyrinth and the upper gate  54 . Thus, the water will flow from the selected labyrinth into the slot  42 , through the bore  30 , and thence down the outlet bore  28  of the outlet connector  26  into a pipe (not shown) that will transport the water, now under a pressure that is reduced in relation to the pressure in the hose, to a drip emission site. 
     Finally, in some embodiments, the emitter may include pressure pads  60  molded onto the cover  12  and spaced at 120 degrees around the lower surface  38  of the cover  12 . These pads are configured to provide balancing forces to the cover  12  as it is rotated about the base  14 . It will be appreciated by those of skill in the art that the reservoir  44  with its plug  16  in the cover will be rotated across the labyrinths sequentially, so that at any one time, the plug  16  will be in contact with only one reservoir. This contact point may cause the cover to be subject to unbalanced force, and so the pads  60  are provided to provide a force-equivalent to the plug, an equivalent force that will always be in contact with the non-selected labyrinths. This feature provides balanced three point forces on the cover, to enhance the overall water tightness of the emitter, and also to provide a more satisfactory tactile communication, for the user, with the emitter. 
     Thus, it will be appreciated that the drip emitter as described presents a user with a simple, compact, and inexpensive system and method for assembling a length of hose having a plurality of drip emitters along its length. Furthermore, each drip emitter may be custom set by the user to have an irrigation rate as desired by the user. For example, if the user wishes to maintain a constant rate of flow from the emitters along the length of the hose, he may set the emitter closest to the water source to be in registration with the labyrinth having the narrowest width. Then, the next emitter may be set to have the labyrinth with an intermediate width. Finally, the emitter furthest from the water source may be set to have the labyrinth with the widest width. This graduated variation in emitters along the length of the hose allows the entire hose to more closely approximate a system that has a constant discharge rate from the emitters positioned along the length of the hose. Furthermore, the emitter  10  has the advantage of being configured to provide a slight throttling effect, under which variations in pressure from the hose translate into attenuated variations in water flow through the emitter. 
     A further advantage of the present invention, is that after the hose and emitters have been in use under a first selection of settings, the user may subsequently return to the emitters and re-set them to another labyrinth setting. Such a need may arise where the hose with emitters attached is to be transported to a different site, where the user concludes that his original settings do not provide the emission profile that he desires, or where environmental changes force a different set of emitter settings. 
     Thus, the embodiments described provide an advantageous system and method for drip emitters. The present invention may, of course, be carried out in other specific ways than those herein set forth without departing from the essential characteristics of the invention. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, while the scope of the invention is set forth in the claims that follow.