Abstract:
A selected range arc settable spray nozzle with pre-set table precipitation rate in which the arc of coverage adjustment is coupled to an upstream flow throttling valve. As the arc of coverage is adjusted, the opening of the upstream flow throttling valve is proportionally adjusted to maintain the precipitation rate substantially constant independent of arc of coverage adjustments. Upstream flow throttling achieved by use of pre-selected number of larger slots for desired flow whose opening area is varied as the arc is being set. The precipitation rate is set by adjusting the throttling valve to provide the desired flow rate for the maximum arc of coverage setting. A pressure compensating valve may also be provided.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is based on and claims benefit of U.S. Provisional Patent Application No. 60/307,686 filed Jul. 25, 2001 entitled SELECTED RANGE ARC SETTABLE SPRAY NOZZLE WITH PRE-SET PROPORTIONAL CONNECTED UPSTREAM FLOW THROTTLING, the disclosure of which is hereby incorporated by reference and to which a claim of priority is hereby made. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Technical Field 
     This invention relates to adjustable arc of coverage spray nozzles, and more particularly, to such nozzles which have preset spray ranges, and in which an upstream throttling valve is proportionally mechanically coupled to the arc of coverage adjustment so that a substantially constant precipitation rate can be selected and provided as the arc of coverage is adjusted. The invention also relates to sprinkler systems including a plurality of such nozzles with different spray ranges. 
     2. Relevant Prior Art 
     Sprinkler nozzles are known which have an adjustable arc of coverage, e.g., as shown in Hunter U.S. Pat. No. 4,579,285, and in my U.S. Pat. No. 5,588,594. 
     My U.S. patent application Ser. No. 10/100,259 entitled SPRAYNOZZLE WITH ADJUSTABLE ARC SPRAY ELEVATION ANGLE AND FLOW, filed Mar. 15, 2002 discloses an adjustable range and arc of coverage nozzle having an adjustable arcuate spray slot in which the arc setting mechanism is linked to an upstream throttling valve to proportionally control the flow to the spray slot as the arc of spray coverage is increased or decreased. Although other arc-settable spray nozzles that have adjustable upstream throttling valves are also known, the upstream throttling valve areas of these are not preset at the factory during assembly to provide the correct flow rate for the desired range of coverage while still maintaining the same larger adjustable slot width, and if adjusted, are not designed to provide proportionally increasing area openings as the arc of coverage is increased for substantially uniform precipitation independent of the arc of coverage setting. 
     The short range adjustable arc nozzles which are now on the market have adjustable arcuate slot orifices that are quite thin e.g., less than 0.030 inch, to reduce the flow rates for the shorter ranges of coverage such as 8 feet. These very thin slots are easily clogged and require fin filters having correspondingly small openings, which themselves are easily clogged. 
     There is accordingly a need for an improved adjustable arcuate slot nozzle in which an upstream proportional flow rate adjusting valve and an arc of coverage adjustment mechanism are coupled so that a substantially constant pre-settable precipitation rate is obtained for different arcs of coverage when the desired flow rate is less than what the adjustable arcuate slot alone provides. The present invention seeks to address this need, in addition to having the nozzles preset at the factory to provide selected shorter ranges of coverage such as 8, 10, 12, and 15 feet. 
     SUMMARY OF THE INVENTION 
     According to this invention, a simple arc-settable spray nozzle may have a relatively large adjustable arc spray slot width (e.g., at least 0.030 in.) for even short range nozzle configurations. Also, by proportionally throttling the flow upstream of the adjustable arc slot, the width of the open area of the arcuate slot can be substantially constant and uniform, independent of the arc setting. The upstream valve can be formed of one or more relatively large axial-width openings which concentrate the flow area in larger size grooves of a selected shape to proportionately open or close the flow area as the upstream throttling valve member is moved axially during setting of the desired arc of coverage. Since the upstream flow is concentrated into a small number of openings or grooves while still providing significant throttling, the adjustable arcuate spray slot may now have a greater opening size while still providing the desired lower flow rate for the short range nozzles. 
     As the arc opening of the adjustable arcuate spray slot is varied by rotation of a spray nozzle deflector and flow control member, a coupled throttling valve element varies the area of the upstream openings. Due to the configuration of the upstream openings, and other parts, the throttling is proportional to the arc opening of the arcuate spray slot. 
     Also, a pressure compensating configuration is disclosed in which one member of the upstream throttling valve is made of a flexible material so that it is pressure responsive. Thus, if the inlet pressure increases, the throttling valve flow area is reduced to compensate for the pressure change. 
     It is accordingly an object of the present invention to provide an improved adjustable arc of coverage sprinkler nozzle. 
     It is another object of the present invention to provide an improved adjustable arc of coverage sprinkler nozzle in which an upstream flow rate adjusting valve provides proportional adjustment to match the rotational and axial movement of the coupled arc of coverage adjustment mechanism so that a substantially constant precipitation rate is obtained for different arcs of coverage, even when the flow rate is preadjusted to be less than would flow from the adjustable arcuate slot alone to provide for the same precipitation rate. 
     It is yet another object of the present invention to provide an improved adjustable arc of coverage sprinkler nozzle in which an upstream flow rate adjusting valve and an arc of coverage adjustment mechanism can be pre-set, for example, during assembly at the factory, to provide a substantially constant pre-selected precipitation rate for different arcs of coverage, and in which different maximum-flow settings of the upstream flow rate adjusting valve are provided for different ranges of coverage. 
     It is a further object of the present invention to provide an improved adjustable arc of coverage sprinkler nozzle with a coupled upstream flow rate adjusting valve and different configurations for different ranges of coverage in which the short range valve configurations are less subject to contamination by dirt than in conventional nozzles. 
     Another object of the invention is to provide a fixed range spray nozzle in which the exit elevation angle of the nozzle flow control deflector determines the spray range and the precipitation rate may be adjusted with an upstream flow control valve whose flow rate is proportionally controlled by a mechanical linkage with the arc of coverage setting mechanism for the adjustable arc of coverage slot. 
     So that the nozzle can be used for different spray ranges as part of a sprinkler system, the flow control mechanism includes an interchangeable deflector that determines the range, and the maximum flow rate for an upstream throttling valve is preset to match the selected range by pre-positioning a movable valve member relative to a plurality of axial outlet orifice slots which concentrate the flow out of the throttling valve, and are configured to provide the required proportional flow adjustability. This construction allows use of outlet slots that are large enough to minimize the risk of obstruction by dirt for even the smallest range nozzle. 
     In a second embodiment, the flow throttling valve body is formed by a resilient diaphragm that includes one or more axial outlet orifice slots. The diaphragm includes a folded area that deflects in response to increased inlet water pressure, and thereby reduces the area of the outlet opening. By properly selecting the thickness and rigidity of the folded area, the changes in the size of the outlet opening can compensate for pressure variations and thus help keep the flow more constant at elevated inlet pressures. 
     Other features and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cross-sectional view of a first embodiment of an adjustable arc spray nozzle according to the invention, including the upstream throttling valve and a matching filter mounted on a partial sprinkler riser tube. 
     FIG. 2 is a cross-sectional view similar to FIG. 1 showing a second embodiment of the invention, in which the upstream throttling valve includes a flexible stator member to provide pressure compensation. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, a first embodiment of an adjustable arc of coverage spray nozzle according to this invention, generally indicated at  1 , is comprised of a cylindrical housing  3 , a central body insert  23 , an adjustable arc-of-coverage flow control member  15 , an upstream flow throttling valve assembly  36 , and a rotatable and axially movable central adjusting shaft  71  with a valving head  73  at its lower end, and an adjusting slot  74  at its upper end. 
     Cylindrical housing  3  is comprised of a generally circular outer wall  5  that defines an internal cavity  7 , an outlet end closure top wall  9 , the latter including a radically spiraled opening  11  that forms an arcuate water discharge orifice or spray slot, and a downwardly depending externally threaded skirt portion  13  that couples the nozzle to a conventional riser tube  30 , by which pressurized water for the sprinkler may be supplied. 
     A filter  90  is positioned within riser tube  30 , and is retained by a shoulder portion  44  that is held between a complementary shoulder  46  on the inside of tube  30  and the bottom end  48  of skirt portion  13  of housing  3 . Filter  90  is of generally conventional construction, and includes a plurality of filter openings  92  through which water flows into an inner cavity  95  at its downstream or top end. 
     Cavity  95  functions as a valve housing or body for flow throttling valve assembly  36 , as described below. 
     Body insert  23  is positioned in central cavity  7  of housing  3 , and is supported therein by circumferentially spaced axial ribs  12 . These can be integrally molded with insert  23 ; alternatively, a separate spacer including ribs  12  may be positioned in cavity  7  around insert  23 . 
     Flow adjusting shaft  71  includes a threaded body portion  72 , a valve adjusting member  73  at its lower end, and an adjustment slot  74 , or the like, at the top. 
     The upper end of flow control adjusting shaft body portion  72  is received in an internally threaded central bore  38  in a body portion  40  of the arc-of-coverage flow control member  15 . The portion of adjusting shaft body  72  that extends below flow control member body  40  is threadedly received in an internally threaded central bore  24  in body insert  23 . 
     The fit between adjusting shaft body  72  and central bore  24  is such that shaft  71  is rotationally and axially movable within bore  24 , while the frictional fit between bore  38  and adjusting shaft body  72  is sufficiently tight that deflector body  40  and adjusting shaft  71  normally move together. Thus adjusting shaft  71  moves axially within bore  24  as deflector body  40  is manually rotated to adjust the arc of coverage. 
     The deflector body  40  includes a sloped axially spiraled surface  17  which cooperates with the radially spiraled housing slot  11  to provide a sealable variable-arc exit opening  19  that is rotationally adjustable from approximately zero to 360 degrees. The slope of deflector body  40  also determines the exit angle of the water stream through exit opening  19 , and therefore, the range of the nozzle. Further details of the construction and operation of the adjustable arcuate orifice spray nozzle is provided in commonly owned U.S. Pat. No. 5,588,594, the content of which is incorporated herein by reference as if fully set forth. 
     Throttling valve member  73  mounted on the lower end of adjusting shaft  71  cooperates with a cavity  95  at the top of filter  90  to form flow throttling valve assembly  36 . Throttling valve member  73  may be formed separately or as an integral part of adjusting shaft  71 . Likewise, the flow valve housing may also be created as a cylindrical skirt depending from the bottom of spray nozzle housing insert  23 . The interior wall  91  of cavity  95  includes a downstream outlet orifice region defined by a plurality of axial slots or shaped flow openings  80  which communicate with the lower end  98  of housing cavity  7 . The outside circumference of throttling valve member portion  82  can be a 1:1 fit with interior wall  91  of the filter cavity  95 . 
     As adjusting shaft  71  moves axially due to rotation of deflector body  40 , throttling valve member  73  moves up or down within cavity  95 . This progressively uncovers (or covers) slots  80 , and changes the flow area and thus the flow rate of valve  36 . After the water flows through outlet slots  80 , it then flows axially upward through passages formed between insert  23  supporting ribs  12 , and through cavity  7  to exit orifice  19 . 
     As will be appreciated by those skilled in the art, the precise configuration of outlet slots  80 , which may have an axially varying width, can be selected in coordination with the configurations of deflector body  40  and arcuate slot  11 , and the pitch of tread  72  to produce desired flow rate variations as valve member  73  moves with shaft  71 . According to this invention, these selections are made so that manual adjustment of the arc of coverage (by rotating deflector body  40 ) produces a proportional change in the flow area of throttling valve  36 . 
     Because of this proportional adjustment, the flow through nozzle opening  19  is substantially constant independent of arc adjustment, and the desired substantially constant precipitation rate can be maintained. 
     As will further be appreciated by those skilled in the art in light of the disclosure herein, the axial position of valve member  73  when slot deflector body  40  is adjusted relative to slot  11  for the maximum arc of coverage determines the maximum flow rate, and therefore the precipitation rate. This remains fixed because adjusting shaft  71  rotates with deflector body  40 . 
     However, as another feature of this invention, the threaded fit between adjusting shaft body  72  and threads  24  is designed to allow shaft  71  to be rotated relative to deflector body  40  for adjustment. Thus, if deflector body  40  is immobilized at the position corresponding to the maximum arc of coverage, and a tool is engaged in adjusting slot  74 , the axial position of valve member  73  can be adjusted. This can be done during assembly at the factory to provide nozzles of different precipitation rates for the same range of coverage with the same parts. 
     The proportional flow control and the ability to preset a full arc of coverage position for throttling valve  36  is an important improvement over existing designs. 
     The slope of deflector body  40  primarily determines the spray range. Thus, a complete sprinkler system having nozzles with one predetermined precipitation rate for different spray ranges can be assembled from common parts except for interchangeable deflector bodies  40 . Filter  90  (even if the upper end serves as the body of throttling valve  36 ) may be a common part with precipitation rate adjusted by pre-positioning adjusting shaft  71  and flow control head  73 . 
     The illustrated construction allows slots  80  each to be larger than the openings  92  in filter  90 . In contrast, a continuous slot surrounding the outer circumference of valve member upper portion  82  would have to be narrower that the filter opening for short range nozzles and would consequently be more likely to be obstructed by dirt. Compensation for this by using a filter with smaller openings would only make the filter more prone to obstruction. 
     Even though the spray nozzle range can be somewhat reduced by a smaller spray deflector elevation angle, if the flow rate is not also reduced, the precipitation rate would be very high for the reduced area of coverage, and the spray angle would have to be reduced to flat or inverted unless the flow is throttled upstream or the adjustable arc discharge slot is made small, (i.e. 0.010 in.) for some of the shortest ranges desired. Reducing the range in half, for example, reduces the flow rate for the same precipitation rate by a factor of four. 
     FIG. 2 illustrates a modified embodiment of the arc settable spray nozzle of this invention. The modified nozzle, generally denoted at  100  is similar to the embodiment previously described except that the upstream throttling valve is formed by valve member  173  and the valve body is formed by a resilient pressure compensating diaphragm  150  which is snap attached to the bottom end of the spray nozzle body  105  at  106 . Member  150  includes an axial slot  191  which functions as an outlet orifice. 
     Pressure compensating member  150  includes a folded area  155 . The structure deflects in response to increased inlet water pressure, thereby reducing the throttling slot opening. By properly selecting the thickness and rigidity of folded area  155 , the changes in the size of the throttling slot opening can compensate for pressure variations by their axial position and thus help keep the flow more constant at elevated inlet pressures. Ribs  160  may be provided to keep the pressure compensating member  150  from being excessively deflected which might totally shut off the flow at very high pressure. 
     Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. the scope of the present invention is therefore not intended to be limited not by the specific disclosure herein.