Patent Publication Number: US-8113443-B2

Title: Rotary sprinkler

Description:
FIELD OF THE INVENTION 
     The present invention is generally in the field of irrigation sprinklers, and more particularly it is concerned with rotary sprinklers adapted for irrigation of areas of various patterns. 
     BACKGROUND OF THE INVENTION 
     The use of sprinklers in order to provide irrigation to a desired area such as a field, a lawn etc. is well known in the art. However, there is often a need to irrigate areas having an irregular pattern. One solution could be providing an array of sprinklers to adequately cover such an area, in an overlapping manner. This however, may cause a problem resulting from excessive watering of certain areas owing to overlapping zones between sprinklers, or to other zones having poor irrigation. This solution is also significantly costly. 
     Another solution is the provision of sprinklers design to emit water at a predetermined shape. An example of such sprinklers is the so-called ‘strip irrigators’ is adapted for emitting water over a narrow strip of land. 
     Several solutions for irrigation of an area having a shape of an amorphic perimeter have been disclosed as well. 
     For example, GB2150862 to Schwartzman discloses a water distributing device comprises a nozzle; means to deliver water to the nozzle; a camming surface concentrically disposed about the axis of rotation of said nozzle; a cam setting means to vary the height of said camming surface; and a cam follower contacting at one end said cam surface and at the other end said spray nozzle to vary the spray pattern emitting from the nozzle in accordance with the relative height set of the camming surface. Valve means responsive to said cam setting vary the quantity of water dispersed in relation to the pattern set by the camming surface. When applied to an oscillating type water-sprinkler, the cam follower means is disposed on the splash plate and rotates around the camming surface. Means are provided to specifically mount the base of the water distributing device attitude in a fixed attitude so that it can be removed and replaced and still maintain the same exact location so that the previously set camming determined spray pattern will still be applicable to the repositioned or to the remounted sprinkler or water distributing apparatus. 
     Hereinafter in the specification and claims, the term sprinkler is used in its broad sense and is used to denote a sprinkler for emitting any liquid, not only for irrigation purposes but also, for example, for frost protecting of crops by mist precipitation, wetting/humidifying areas and materials, etc. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a sprinkler for programmable and controlled discharge of liquid onto areas having a different geometrically shaped perimeter, whilst maintaining a substantially constant liquid precipitation over said area. 
     This is obtained by providing a sprinkler wherein liquid precipitation is dominated by variable liquid flow rate emitted through the sprinkler, variable liquid emitting distance (measured from the sprinkler—i.e. irrigation radii) and optionally, controllable speed of the sprinkler. 
     According to the invention there is provided a sprinkler for discharging liquid onto an area with a predetermined geometrically shaped perimeter, said sprinkler comprising a housing fitted with a flow chamber accommodating a hydraulic motor for rotating a sprinkler head mounted on said housing, the housing comprising a first nozzle and a second nozzle being in flow communication with the outlet end of the flow chamber, said first nozzle fitted for discharging liquid at a constant flow rate; said sprinkler further comprising a dynamic liquid deflector associated with the second nozzle, and biased by an array of biasing elements, each adapted to dynamically bias said liquid deflector to a predetermined angle, thereby determine a deflection angle thereof. 
     According to an embodiment of the invention the hydraulic motor is dynamic and has a speed regulator for governing rotary speed of the sprinkler head depending on the flow rate emitted through the second nozzle. According to this embodiment the dynamic hydraulic motor is linked to the dynamic liquid deflector whereby deflection of the liquid deflector results in change of rotary speed of the dynamic hydraulic motor. 
     Variable speed of the dynamic hydraulic motor may be obtained, for example, by a coupler associated at one end with the liquid deflector and at an opposite end thereof with an axially displaceable turbine of the dynamic hydraulic motor, said turbine being mounted within a chamber formed with one or more tangentially extending liquid jet apertures, whereby axial displacement of the turbine results in its axial displacement with respect to said one or more apertures, which in turn entails reducing/increasing of the rotation of said turbine and the associated housing. 
     According to another embodiment of the invention the housing is fitted with a first feed line and a second feed line, both extending from the flow chamber and each having an outlet end; said first feed line extending through the hydraulic motor to thereby rotate the sprinkler head at a substantially constant speed, said first feed line fitted at an outlet end thereof with the first nozzle fitted for discharging a liquid at a substantially constant flow rate; said second feed line being fitted at an outlet end thereof with the second nozzle. 
     According to a particular design of the invention the second nozzle is fitted with a flow regulator for regulating liquid flow discharged through the second nozzle, where deflection of the dynamic liquid deflector entails simultaneous governing of the flow regulator, to thereby emit liquid through the second nozzle at a flow rate corresponding with the range (irrigation radius) set by a respective biasing element. 
     According to embodiments of the present invention the first nozzle is adapted for discharging a constant amount of liquid at substantially short/near range. By a particular design, the first nozzle is fitted for discharging a liquid at a substantially constant flow rate and a fixed range to emit liquid over a circular pattern or a sectorial pattern. 
     Furthermore, the second nozzle is fitted for discharging a variable liquid flow rate at longer and variable ranges. 
     A wide variety of hydraulic motors may be used in conjunction with the sprinkler of the present invention for rotating the sprinkler head. According to one embodiment of the invention the hydraulic motor is of the type comprising a distribution member rotatable with respect to the housing, the inlet chamber being in flow communication with an inlet port of the housing and with the sprinkler head, and an impeller mechanism articulated with the second nozzle. 
     According to a particular embodiment, the impeller mechanism is ball-driven wherein said inlet chamber is formed with tangentially directed water inlet apertures for imparting to the ball a rotational motion, whereby impact of the ball and the impeller mechanism results in the transfer to the impeller mechanism of the ball&#39;s momentum, causing rotational displacement of the impeller element and its associated second, long-range nozzle. However, according to another embodiment, the motor is an electric motor. Still further, the motor is fitted with a gear mechanism to provide a speed-power conversion from a higher speed to a slower but more forceful output. 
     According to an embodiment of the invention, the housing is formed as an essentially cylindrical tube having a static base member and a rotatable distribution member articulated thereto, said base member comprising the inlet chamber wherefrom said first and said second feed line extend, and adapted to be connected to a liquid supply line. The discharge end accommodating the first nozzle and the second nozzle; the rotatable distribution member is fitted with the dynamic liquid deflector and a sprinkler top comprising the radial biasing elements. 
     The sprinkler top is spaced from the static base member and is fitted with a plurality of radially directed biasing elements, said biasing elements being independently radially displaceable so as to form an imaginary path extending between said plurality of biasing elements, whereby a cam/roller follower associated with the dynamic liquid deflector travels over said biasing elements to thereby angularly disposition the dynamic liquid deflector. 
     The biasing elements are radially directed towards a longitudinal (vertical) axis of the sprinkler, each biasing element being radially displaced within the sprinkler top so as to adjust the distance of a proximal (inner-most) end of each biasing member from said longitudinal axis. Adjusting the radial distance of the biasing members may be by screwing along a helical path, pressure fit, etc. 
     The arrangement is such that the imaginary path extending between said plurality of biasing elements corresponds at an inverted fashion with the perimeter of the irrigated area, i.e. biasing elements associated with outermost locations of the area are radially most radially retracted (radially inwardly), and vise versa. 
     Angular disposition of the dynamic liquid deflector is a pivotal motion with respect to a longitudinal axis of the sprinkler. 
     The sprinkler top is spaced from the static base member by one or more support studs having a hydro-dynamic cross-section so as to cause minimal interference with liquid jets emitted from the first and second outlet nozzles. 
     The sprinkler top is fixedly spaced from the static base member though it may be rotatably displaced thereabout between a plurality of discrete positions. 
     The flow regulator fitted at the second outlet nozzle is fitted for partially obstruct the second feed line, thereby regulating the amount of liquid discharged threw the second nozzle. According to a design of the invention, the flow regulator is in the form of a plunger at least partially impinging with the second feed line, thereby restricting the cross-section of said second feed line and obstructing fluid flow. Furthermore, the plunger&#39;s end may be configured in a variety of cross-sectional forms, thus allowing more intricate regulation of the discharged liquid. 
     According to embodiments of the invention the plunger of the flow regulator may be interchangeable. Furthermore, the flow regulator may be fitted with a biasing spring biasing it to minimal its interference within the second feed line. 
     According to a particular design, the dynamic liquid deflector is in the form of an arm pivotally articulated to the rotatable sprinkler head such that a deflecting end thereof extends in front of the second outlet nozzle for selectively deflecting liquid emitted therefrom. A cam follower member is fitted on said dynamic liquid deflector for engagement with the array of radial biasing elements. 
     The deflecting arm may be hinged to the rotatable sprinkler head such that pivotal displacement of the arm under biasing effect of the biasing elements, in a substantially radial direction, entails corresponding pivotal displacement of the deflecting end about an arced path opposite said second outlet nozzle, thereby altering the angle of discharge of the liquid jet. The deflecting end may be formed with an essentially flat deflecting portion, or it may be formed in different shapes, e.g. concave, with radial grooves, etc. for imparting the emitted liquid jet different desired patterns, such as splitting or converging the jet, to thereby obtain better coverage of the concerned area. According to an embodiment of the invention, the deflecting portion may be interchangeable. 
     According to a specific design of the invention, a middle portion of the deflecting arm bears over a distal end of said flow regulator plunger projecting from the sprinkler head, whereby deflection of the dynamic fluid deflector governs the amount to which the plunger of the flow regulator impinges with the second feed line, to thereby regulate the amount of liquid emitted from the second nozzle in correlation with the desired angle of discharge, i.e. with the distance of the emitted jet, thereby confirming constant precipitation. 
     According to a specific embodiment the plunger of the flow regulator is formed at its distal end with a concave surface corresponding with a bottom surface of the flow deflecting arm such that pivotal displacement of the arm entails substantially pure rolling motion over said plunger. However, according to other embodiments, the distal end of the plunger and the bottom surface of the flow deflecting arm are so designed as to impart the plunger axial displacement at non-linear ratio responsive to pivoting of the deflecting arm. For example, at the low elevations of the of the deflecting arm (i.e. where the deflecting tip nears to the second outlet nozzle) the axial displacement of the plunger is non linear and will be significantly more then at high elevations of the of the deflecting arm (i.e. where the deflecting tip departs from the second outlet nozzle), thereby obtaining varying interference with liquid flow towards the second nozzle. 
     Accordingly, when the angle of deflection is greater (i.e. the deflecting arm is pivoted and interferes more with the second nozzle), the flow regulator is further depressed into the second feed line, thus blocking a larger portion of the outlet of said second feed line. This results in a lesser amount of liquid being discharged from the second, long-range nozzle. However, the opposite occurs when the deflecting arm is less pivoted, i.e. the plunger less interferes with the second feed line and a greater flow is admitted through the second nozzle, corresponding with the long range, thereby allowing more uniform precipitation of said area. 
     In operation, as will be discussed in detail later, each biasing element is adapted to determine the amount to which the biased end of said dynamic liquid deflector is pivoted. This in turn determines to which extent the deflecting end thereof obstructs the second, long-range nozzle, and consequently the angle of liquid discharge, and also the extent to which the flow regulator interferes the second feed line, and consequentially with the liquid flow rate through the second nozzle. 
     In operation, liquid from the inlet chamber flows into the inlet end of said first and said second feed lines. The liquid running through said first feed line passes through the hydraulic motor, thereby operating it at constant rotary motion of the discharge port of the sprinkler (also with respect to a given liquid pressure supply). When exiting the hydraulic motor, the water reaches the outlet port and the first, short-range nozzle and provides a constant liquid flow rate at a constant angle to the area to be irrigated. 
     Liquid flowing through the second feed line directly reaches the second, long-range nozzle, where it may be obstructed by the deflecting end of the dynamic liquid deflector. During rotation of the second nozzle, the biased end of the dynamic liquid deflector alternately comes in contact with a different biasing element, whereby the extent of obstruction of the flow through the second feed line towards the second nozzle, varies in accordance with the radial projection of each biasing element and simultaneously the distal end of the flow regulator is biased downwards at a corresponding extent consequently deflecting liquid emitted from the second nozzle. 
     Thus, in each direction the nozzles of said first and said second feed lines are directed, the angle of discharge may be different allowing coverage of virtually any geometric planar shape of an irrigated area. Furthermore, the constant amount of water being discharged from the first, short-range nozzle of said first feed line, and the regulated amount of liquid discharged from said second, long-range nozzle allows uniform precipitation of the liquid across all the irrigated area. More particularly, the first feed line and the second feed line are independent. Therefore a change in the amount of discharged water from the second feed line does not affect the discharge from the second feed line, facilitating uniform irrigation throughout the entire area. 
     Lowering the deflecting angle of liquid distributed throughout the second nozzle may result in reducing the rotational speed of the distribution head and thus speed increase is required so as to maintain a substantially constant rotational speed of the distribution head. 
     According to still an embodiment of the present invention, the sprinkler is fitted with a flow regulator to generate a substantially constant liquid flow rate directed to both the first and second nozzles. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to understand the invention and to see how it may be carried out in practice, some embodiments will now be described, by way of non-limiting examples only, with reference to the accompanying drawings, in which: 
         FIG. 1A  is a schematic side view of the sprinkler according to the present invention; 
         FIG. 1B  is a schematic cross section along line I-I in  FIG. 1A , with the irrigation head removed; 
         FIG. 2  is a longitudinally sectioned view of a top portion of the sprinkler of  FIG. 1A , with a deflecting mechanism removed; 
         FIG. 3A  illustrates the discharge end of the sprinkler along with the deflecting mechanism and a biasing element used in the regulator; 
         FIG. 3B  is an enlargement of the deflecting portion marked III in  FIG. 3 ; 
         FIGS. 4A and 4B  illustrate the deflecting mechanism in two respective positions; 
         FIG. 5  is a top isometric view of the liquid deflector and the associated biasing array; 
         FIG. 6  is a schematic drawing of a lawn perimeter and arrangement of biasing elements used in the sprinkler of  FIG. 1A ; 
         FIGS. 7A to 7D  illustrate samples of distal ends of a flow regulator; 
         FIG. 8  is a longitudinal section of a sprinkler according to another embodiment of the present invention; and 
         FIG. 9  is partially sectioned longitudinal view of a sprinkler according to a modification of the invention, with the sprinkler head removed. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Referring to  FIG. 1A  there is provided a sprinkler generally designated  10  having an essentially cylindrical body  12  having a longitudinal axis X-X with a static base member  14  fitted for coupling to a liquid supply line (not shown), and a rotatable sprinkler head (distribution member)  16  serving as a discharge end. The sprinkler  10  is adapted to be attached to a feed port (not shown) located in or in the vicinity of an area to be irrigated such that an irrigation liquid, e.g. water may be introduced through the static base member  14  and be discharged through the rotatable distribution member  16 , as will be described hereinafter. 
     Turning to  FIG. 2  the sprinkler  10  is formed with a flow chamber  13  being in flow communication with the liquid supply line (not shown) and splitting into a first feed line generally designated  20  and a second feed line  30 . The first feed line  20  has a first inlet in the form of inlet ports  21   a , and being in flow communication with the flow chamber  13 , and an outlet  22  located at the rotatable distribution member  16  of the sprinkler, terminating at a first outlet nozzle  23 . 
     The second feed line  30  has an inlet  31  located at the flow chamber  13 , and an outlet  32  located at the rotatable distribution member  16  of the sprinkler  10  terminating at a second nozzle  33 . The first nozzle  23  of the first feed line  20  is a substantially short-range discharge nozzle, and the second nozzle  33  of the second feed line  30  is a longer range discharge nozzle. Between the inlet ports  21   a  and the outlet  22 , the first feed line  20  extends through a hydraulic motor assembly generally designated  50 . The second feed line  30  on the other hand passes directly through the body  12  of the sprinkler  10  without passing through the motor assembly  50 . 
     The rotatable distribution member  16  of the sprinkler  10  is formed with a coupling portion  40  rotatably and sealingly coupled at a top end of the sprinkler body  12 . The motor assembly  50  comprises a turbine wheel  52  extending opposite the inlet ports  21   a  and mounted on a first axle  53 , a coaxial pinion gear  54  engaged with a gear  55  mounted on a second, parallel axle  56 . Fitted within a top chamber  57  and coaxially mounted on the second axle  56  there is a rotary gear  58  which is engaged for rotation with an internal gear  42  formed at a bottom of the coupling portion  40 . The gear train serves a speed reducing mechanism. 
     Liquid entering through the inlet ports  21   a  strike against the turbine wheel  52  causing it to rotate and resulting in revolving of the coaxial pinion gear  54  which in turns entails rotary motion of the gear  55  and the associated gear  58 , resulting in imparting rotary motion to the sprinkler head  16 . 
     However, it should be noted that various impeller mechanisms may be used, for example a ball-driven in which the inlet chamber is formed with tangentially directed water inlet apertures adapted for imparting to the ball a rotational motion. The impact of the ball and the impeller mechanism results in the transfer to the impeller mechanism of the ball&#39;s momentum, causing rotational displacement of the impeller element and its associated second, long-range nozzle  23 . It should also be noted that instead of a hydraulic motor there may be used an electric motor for rotating the sprinkler head  16  with respect to the base  12 . 
     In operation, water supplied from a liquid supply line (not shown) enters the flow chamber  13  of the static base member  14  and is then divided into two routes: one passing through the inlet a  21   a  of the first feed line  20  entering the motor  50 , operating it, and exiting through the first outlet port  22  and out through the short-range nozzle  23 , and the other passing through the second inlet port  31  of the second feed line  30  to be discharged through the second outlet port  32  and long-range nozzle  33 . 
     The outlet  32  of the second feed line  30  is formed with a fork like extension  34  adapted for receiving therein a flow regulator  80 , the purpose of which will be explained in detail later. 
     Turning to  FIGS. 3A and 3B , the dynamic liquid deflector  60  is illustrated in further details, being in the form of a deflecting arm  62  pivotally articulated through pivot  67  of extension  69  to an upward extension  44  ( FIG. 2 ) of the to the rotatable sprinkler head (distribution member)  16 . The deflecting arm  62  is formed with a deflecting portion  64  adapted to selectively come in contact with the water jet emitted from the second nozzle  33  in order to change its angle as represented by arrows  65 . 
     The dynamic liquid deflector  60  further comprises a cam follower  66  in the form of a roller follower rotatably mounted on an axle  67   a  and adapted to come in contact with an array of radial biasing elements  70  only one of which, referred to as an ‘in-duty biasing element’ is shown in  FIG. 3A . 
     The deflecting arm  62  is pivotally hinged such that displacement of the cam follower  66  of the deflecting arm  62  towards the main axis X-X entails corresponding pivotal displacement of the deflecting arm  62  in direction of arrow P in  FIG. 3A . The movement of the deflecting portion  64  towards the long-range nozzle  33  thereby changing the angle of the discharged water as shown by arrows  65 . As seen in  FIG. 3B  the deflecting portion  64  is formed with an essentially flat portion  64   a  having grooves  64   b  therein, adapted for splitting the discharged water into a number of streams for better coverage of the irrigated area. These grooves may however have deferent forms for diverting or converging a liquid jet emitted from the nozzle  33 . It is however noted that the deflecting portion  64  interferes with the liquid jet emitted from the nozzle  33  only under a certain elevation (pivotal displacement). 
     Reverting to  FIG. 1  and with further reference also to  FIG. 5 , the sprinkler  10  has a top head  18  of an essentially circular shape having its center coinciding with the main axis X-X of the cylindrical body  12 . The sprinkler top  18  is spaced from the top end of the static base member  12  by four studs  45 , which as can be seen in  FIG. 1B  said studs  45  have a hydrodynamic cross section suited for minimal obstruction of the water jet emitted from the nozzles  23  and  33 . 
     The sprinkler top  18  is formed on its sidewall  18   a  with a plurality of radially extending positioning holes  19  spaced around the perimeter thereof. The axis of each of those positioning holes  19  is directed at the center of the sprinkler top  18 . Each of the positioning holes  19  receives a radial biasing element  70  ( FIGS. 4 and 5 ). Each of the holes  19  and the biasing element  70  is threaded to allow axial displacement of the radial biasing elements  70  therein, in a radial direction. 
     Reverting to  FIGS. 1 to 4  a flow regulator  80  is provided in the form of a plunger  82  received within the extension  34  of the second feed line  30  and is axially displaceable therein such that its proximal end  84  is suited for partially obstructing the flow of liquid from the second feed line  30  into the long-range nozzle outlet  32 , and its distal end  86  projects from the distribution head  16 . The flow regulator  80  is fitted with a biasing spring  88  positioned between the distal end  86  end a base of a receiving cavity  89  ( FIG. 1 )) for biasing the plunger  82  upwards. By changing the axial position of the flow regulator  80 , the amount of liquid discharged through the long-range nozzle  32  may be governed. It is to be appreciated that rather then biasing spring  88  there may be other arrangements for biasing the plunger outwards from the extension  34 ) e.g. hydraulic arrangements. 
     As can best be seen in  FIGS. 3A ,  4 A and  4 B the distal end  86  of the flow regulator  80  is in the form of a hemisphere being in contact with a middle portion of the deflecting arm  62  of the dynamic fluid deflector  60 , whereby pivotal deflection of the arm  62  by a biasing element  70 , in direction of arrow P entails depression of the plunger  82  downwards into the extension  34  further interfering with flow through the outlet  32  of the second feed line  30 . 
     In assembly, after mounting the sprinkler  10  onto the main feed line (not shown) in order to irrigate a certain area, each of the radial biasing elements  70  is radially adjusted within the respective positioning hole  19  of the sprinkler top  18  according to the geometric shape of the perimeter of the area to be irrigated. 
     In operation, the liquid from the feed line enters the flow chamber  13  of the static base member  14  wherein part of the liquid enters the inlets  21   a  of the first feed line  20 , and another portion of the liquid enters the inlet  31  of the second feed line  30 . The liquid flowing through the first feed line  20  reaches the hydraulic motor  50 , where it operates the gears as discussed hereinabove, resulting in rotation of the sprinkler head  16  with respect to the cylindrical body  12  of the sprinkler  10 . When exiting the hydraulic motor  50 , the liquid flowing through the first feed line  20  reaches the short-range nozzle  23  and provides a constant amount of liquid at a constant angle to the area to be irrigated. 
     The liquid flowing through the second feed line  30  reaches the second outlet  32  where it is first obstructed by the proximal end  84  of the flow regulator, to an extent determining the amount of water to pass towards the long-range nozzle  33 , in correspondence with the extent of radial protrusion of the biasing elements  70 . 
     After reaching the long-range nozzle, the liquid jet emitted from the outlet nozzle  33  may be obstructed by the deflecting portion  64  of the dynamic liquid deflector  60 , determining the actual irrigation Range. During rotation of the sprinkler head  16 , the cam follower  66  of the dynamic liquid deflector  60  alternately comes in contact with a biasing end  74  of a different biasing element  70 , whereby the extent of obstruction of the second nozzle  33  varies according to the radial distance of each of the biasing end  74  from the main axis X-X of the cylindrical body  12 . 
     The distal end of the flow regulator  80  is positioned under the deflecting arm  62  such that deflection of the deflecting portion  64  of the dynamic liquid deflector  60  entails corresponding depression of the proximal end  84  of the plunger  82  into the extension  34 . 
     In  FIG. 4A , the deflection arm  62  is shown to be only slightly biased in direction of arrow P. The in-duty biasing element  70 ′ is partially displaced in the inward radial direction, whereby its biasing end  74  slightly biases the cam follower  66 , at an angle α°. As a result, the deflecting portion  64  of the deflecting arm  62  does not interfere with the jet emitted through the nozzle  33  so as to obtain substantially long range irrigation. Plunger  82  is depressed depending on the radial displacement of the in-duty plunger  70 ′. In the present example, the deflecting portion  64  of the arm  62  does not interfere with the emitted liquid jet, nor does the plunger  80  is project into the outlet  32 , leaving a wide flow path and thus not interfering with the liquid flow passing towards the outlet nozzle  33 , to thereby achieve a maximum range and flow rate. 
     Turning to  FIG. 4B  the deflection arm  62  is shown in a biased position. An in-duty biasing element  70 ″ is received within the positioning hole  19  and projects to a significant extent radially inwards such that its biasing end  74  comes into contact with the cam follower  66  thereby biasing it to pivot in direction of arrow P, at an angle β°. As a result, the deflecting portion  64  of the arm  62  deflects the stream of liquid emitted from the long range nozzle  33 , and the plunger  82  is depressed, leaving a narrowed flow path  73  leading to the discharge end of the long range nozzle  33 , whereby the liquid flow is reduced in correspondence with deflection of the jet in a nearer range, in accordance with the irrigation pattern dictated by the extent of radial setting of the in-duty biasing element. 
     Thus in each direction the discharge nozzles  23  and  33  are directed, the angle of discharge and liquid flow rate are different, allowing coverage of virtually any geometric planar shape of irrigation area. Furthermore, the correspondence between the deflection extent of the liquid by the dynamic liquid deflector  60  and the obstruction of the liquid flow by the flow regulator  80  provides substantially uniform precipitation of water across all of the irrigated area. More particularly, the first feed line  20  and the second feed line  30  are independent, i.e. the amount discharged from the long-range nozzle  32  does not affect the constant amount of water discharged from the short-range nozzle  22 , facilitating uniform irrigation throughout the entire area. 
     Turning to  FIG. 6 , a lawn  100  is schematically shown to have an amorphic geometric contour  110 . The sprinkler is positioned within the lawn and the sprinkler top  18  with biasing elements  70  is also schematically shown. The biasing elements  70  are so positioned with respect to the central axis X-X of the sprinkler  10  that the an imaginary line joining all the biasing ends  74  forms an amorphic sprinkler contour  120 , which is proportionally inverse to the lawn contour  110  of the lawn  100 . 
     For example, in order for water from the sprinkler to reach a distant point A on the lawn contour, the biasing end  74  of the corresponding biasing element  70 , positioned opposite point A about the central axis X-X, needs to be spaced from the central axis X-X to an extent AA, corresponding to the distance of point A from the axis X-X. For a proximal point B, the biasing end  74  of the corresponding biasing element  70  needs to be spaced closer to the central axis X-X, to an extent ΔB, such that ΔB&lt;ΔA. 
     Thus, by presetting the biasing elements  70 , the biasing end  74  thereof may be manipulated so as to allow the sprinkler to perform irrigation of virtually any possible lawn contour. 
     With further attention to  FIGS. 7A to 7D  there are illustrated samples of distal ends of plunger  82 ′ to thereby obtain different flow patterns towards the second outlet  32 . In  FIG. 7A  the plunger tip  91  is hemispheric; in  FIG. 7B  the plunger tip  93  has a half-circle section and in order to retain its orientation within the extension  34  ( FIG. 2 ) a key  94  is provided for engagement by a corresponding groove (not shown) in the extension; in  FIG. 7C  the plunger tip  95  has the shape of truncated cone and in  FIG. 7D  the plunger has a flat tip  95 . It is realized that other shapes may be imparted to the distal ends of the plunger, depending however on the desired result. 
     Further attention is now directed to  FIG. 8  of the drawings illustrating a longitudinal section through a sprinkler in accordance with an embodiment of the invention, generally designated  100 . 
     The sprinkler is formed with a housing  102  stationary fixable to a liquid supply line (not shown). A sprinkler head  104  is fixedly mounted on the housing  102  by a downwardly extending skirt  105  coaxially mounted over the stationary housing cylinder  102 . Rotatably mounted on the housing  102  there is a distribution head  106 . An irrigation head generally designated  108  (composed of the sprinkler head  104  and the distribution head  106 ) is fitted at the top of the housing  102  and is substantially similar to that disclosed in connection with the previous embodiment. 
     Housing  102  is formed with a flow chamber  112  being in direct flow communication with the supply line (not shown). Extending within the housing  102  there is a hydraulic motor generally designated at  114  comprising a turbine chamber  116  in the form of a closed chamber fitted at its bottom end with a one-way inlet valve  118  and with one or more tangentially extending inlets  120  adapted for generating a flow in a tangent direction giving rise to rotation of a turbine wheel  124  mounted on an axle  126  coaxial with a longitudinal axis Z-Z of the sprinkler. 
     The axle  126  projects through an upper wall  128  of the chamber  116  and is fitted with a gear transmission generally designated  130  comprising a first gear wheel  132  mounted on the axle  126  and a second gear wheel  134  which in turn is rotatably engaged with an internally geared portion  138  of the skirt portion  105  of the sprinkler head  104 . 
     It is noticed that axle  126  extends into a housing  142  and projects through its top end terminating with a plate segment  144  where it is normally biased upwards owing to coiled spring  146  bearing at its upper end at the bottom end of plate segment  144  and at its bottom end on a top surface of the housing  142 . This arrangement results in that the gear transmission  130  together with the turbine  124  are axially displaceable within the housing  102 , however without disengaging any of the gear transmission assembly from one another during such axial displacement. 
     Such axial displacement within the housing  102  entails corresponding displacement of the turbine  124  opposite the tangential openings  120  resulting in increasing/decreasing of the rotational speed of the turbine  124  owing to its change of location with respect to the tangential openings  120 , i.e. strengthening/weakening the impinging effect of water jets immersing through the apertures  120  about the turbine wheel  124 . 
     Any change in rotational speed of the turbine  124  is reflected in corresponding change of rotation of the distribution head  106  which in turn is articulated thereto, as discussed hereinabove. 
     Contrary to the previous embodiment, the plunger  156  of the flow regulator is received within a throughgoing recess  150  with a rod  154  extending from the plunger  156 , said rod bearing at its lower end  158  against the plate portion  144  integral with the axle  126 . The plunger  156  and the rod  154  may be, according to an embodiment of the invention, a unitary item with the upper part thereof not interfering with flow rate through the second nozzle. 
     In operation, after the array of biasing elements  70  has been set in accordance with the contour of the area to be irrigated (this is performed in the same manner as disclosed in connection with the previous embodiment, resulting in the same flow regulation of the liquid immersing through the second nozzle  33 ′ and in corresponding deflection of the deflector arm  62 ′) the rod  154  will axially displace in correspondence with axial displacement of plunger  156  of the flow regulator resulting in axial displacement of the axle  126  and the turbine  124  articulated thereto. 
     As a result, when the deflection arm  62 ′ is pivoted in a counter-clockwise direction owing to the position of an in-duty biasing element  70 ′, it will depress the rod  154  resulting in corresponding faster rotation of the distribution head  106 , at a lower flow rate, suited for shorter range irrigation. However, when the in-duty biasing element  70 ′ is axially retracted the plunger  156  projects moiré, resulting in that the rod  154  does not apply pressure on axle  126  whereby the turbine  124  is at its maximal elevation suited for an increased jet flow rate, for output of slower speed suited for irrigation at longer range. This will result in maintaining a substantially constant liquid precipitation over the irrigated area. 
     It is noted that the first nozzle  23 ′, adapted for irrigation at the shorter range is in flow communication with the flow chamber  112  and the liquid supplied to the nozzle  23 ′ remains at a substantially constant flow rate, regardless of any change in speed of the sprinkler. The second nozzle  33 ′ however emits a nozzle eject at altering flow rates, responsive to axial displacement of plunger  156  (and may further be deflected by the deflector arm  62 ′) depending on the extent of radial displacement of the biasing elements, in compliance with the contour of the irrigated area. However, the irrigation head with both nozzles rotate at a varying speed which is a resultant of the contour of the irrigated pattern, as disclosed hereinabove. 
     The sprinkler  180  illustrated in the embodiment of  FIG. 9  is similar to the previous embodiments as far as the irrigation head  182  (sprinkler head not shown) with the major difference residing in the provision of a flow regulator designated at  184  fitted within a hydraulic motor assembly generally designated  186 . The motor assembly is secured within the static housing  188  by several supports  190 , however enabling liquid flow also upwards towards the irrigation head and the respective nozzles, as discussed herein before in connection with the previous embodiments. The housing  182  is further formed with a first compartment  194  accommodating the flow regulator  184  and a accommodating the hydraulic motor. 
     The first compartment  194  is formed with one or more flow inlets  198  and several inclined outlets  202  extending into the second compartment  196  such that liquid jets emitted therefrom impinge with blades of a turbine wheel  204  received within the second compartment  196  and impart the turbine rotary motion. The turbine is mounted on an axle  207  which is fitted at an upper end thereof with a pinion gear  209  extending outside said second compartment. Pinion gear  209  is engaged with a gear train  212  for speed reduction, which gear train ends with a rotation gear  214  engaged in turn with a gear rack  218  formed at the skirt portion  222  of the sprinkler head. 
     The arrangement is such that liquid enters the housing  188  and into the flow regulator compartment  194  from which it flows into the motor compartment at a substantially constant flow rate to rotate the hydraulic motor, resulting in rotation of the irrigation head. Liquid then flows into the irrigation head chamber  230  and further towards the first nozzle  232  and the second nozzle  234 . 
     Whilst several embodiments have been shown and described, it is to be understood that it is not intended thereby to limit the disclosure of the invention, but rather it is intended to cover all modifications and arrangements falling within the spirit and the scope of the invention, mutatis mutandis.