Abstract:
Provided is agricultural equipment for delivering fluid to a field. The agricultural equipment includes a system having a plurality of flow indicator sensors for providing an output indicative of whether or not fluid is flowing through the sensors above or below a prescribed rate and an indicator panel for providing at least one of a visual or an audio indication to an operator indicative of whether or not fluid is flowing through the flow indicator sensors above or below the prescribed rate. The indicator panel may be provided in a location to allow an operator to determine when an interruption occurs, for example by viewing a visual indication on the indicator panel, without the operator having to look away from a direction of motion. In this way, the operator can safely and efficiently determine if there is an interruption and then take the necessary steps to clear the interruption.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/860,349 filed Jul. 31, 2013, which is hereby incorporated herein by reference. 
     
    
     FIELD OF INVENTION 
       [0002]    The present invention relates generally to agricultural equipment, and more particularly to agricultural equipment for delivering fluid, such as anhydrous ammonia to a field. 
       BACKGROUND 
       [0003]    Anhydrous ammonia may be applied to soil by farmers as a fertilizer. Farmers often use a nurse tank containing pressurized liquid anhydrous ammonia as a source. The nurse tank may be provided on a cart that is transported by a farm vehicle, such as a tractor, across a field while the anhydrous ammonia is distributed to the soil via a tool bar connected to the nurse tank. One or more hoses may be used to connect the nurse tank and the tool bar. The one or more hoses may be coupled to the nurse tank, and more particularly to a withdrawal valve of the nurse tank and/or the tool bar in any suitable manner, such as by couplers configured to be threaded together, such as acme couplers. 
       SUMMARY OF INVENTION 
       [0004]    The present invention provides agricultural equipment for delivering fluid to a field. The agricultural equipment includes a system having a plurality of flow indicator sensors for providing an output indicative of whether or not fluid is flowing through the sensors above or below a prescribed rate and an indicator panel for providing at least one of a visual or an audio indication to an operator indicative of whether or not fluid is flowing through the flow indicator sensors above or below the prescribed rate. The indicator panel may be provided in a location to allow an operator to determine when an interruption occurs, for example by viewing a visual indication on the indicator panel, without the operator having to look away from a direction of motion. In this way, the operator can safely and efficiently determine if there is an interruption and then take the necessary steps to clear the interruption. 
         [0005]    According to one aspect of the invention, a system for delivering fluid to a field using an agricultural implement is provided. The system includes a plurality of laterally spaced applicators, a manifold connectable to a source of fluid to be delivered to the field, a plurality of lines, each line connecting the manifold to a respective one of the plurality of applicators, a plurality of flow indicator sensors, each flow indicator sensor being connectable between the manifold and a respective one of the plurality of lines and configured to provide an output indicative of whether or not fluid is flowing through the sensor at a prescribed rate, and an indicator panel for receiving the output from the plurality of flow indicator sensors and for providing at least one of a visual or an audio indication to an operator based on the outputs. 
         [0006]    The indicator panel provides a visual indication for each of the plurality of flow indicator sensors based on the outputs of the respective flow indicator sensors. 
         [0007]    The indicator panel includes an indicator for each of the plurality of flow indicator sensors. 
         [0008]    The indicators are light-emitting diodes. 
         [0009]    The system further includes wires connecting the plurality of flow indicator sensors to the indicator panel. 
         [0010]    The system further includes a junction box, wherein the wires include a wire connecting each of the flow indicator sensors to the junction box and a wire connecting the junction box to the indicator panel. 
         [0011]    The system further includes a cable having one end coupled to the indicator panel and another end configured to be coupled to a battery to provide power to the indicator panel. 
         [0012]    Each flow indicator sensor has a cable coupled thereto that has a connector configured to mate with a corresponding connector coupled to a respective one of the wires. 
         [0013]    The indicator panel further includes a power switch, indicia identifying each of the plurality of applicators, and one or more connectors configured to couple to the wires. 
         [0014]    Each flow indicator sensor includes a body having a first end configured to be coupled to the manifold, a second end configured to be coupled to one of the plurality of lines, and an axially extending cavity, a reed switch coupled to the body, and a poppet including a poppet body and a magnet disposed in the poppet body, the poppet being biased in a first position and being configured to be moved from the first position to a second position by fluid flowing through the axially extending cavity to activate/deactivate the switch. 
         [0015]    The body has an inner wall defining the axially extending cavity, and wherein the wall includes a plurality of flutes that allow flow through the cavity around the poppet. 
         [0016]    The flutes have a progressively larger flow area extending from a first end of the cavity to a second end of the cavity. 
         [0017]    The indicator panel is configured to be located inside a cab of a vehicle. 
         [0018]    The indicator panel is located in a cab of the vehicle. 
         [0019]    According to another aspect of the invention, an agricultural apparatus is provided that includes a plurality of flow indicator sensors connectable between a manifold of an agricultural implement and a delivery line for delivering fluid from the manifold to a respective applicator, each flow indicator sensor providing an output indicative of whether or not fluid is flowing through the sensor above or below a prescribed rate, an indicator panel for receiving the outputs from the plurality of flow indicator sensors, the indicator panel including an indicator for each of the plurality of indicators for providing at least one of a visual or an audio indication to an operator indicative of whether or not fluid is flowing through the respective flow indicator sensor above or below the prescribed rate, and a plurality of wires connecting the plurality of flow indicator sensors to the indicator panel. 
         [0020]    Each indicator provides a visual indication for the respective flow indicator sensor. 
         [0021]    The indicators are light-emitting diodes. 
         [0022]    The apparatus further includes a junction box, wherein the plurality of wires includes a wire connecting each of the flow indicator sensors to the junction box and a wire connecting the junction box to the indicator panel. 
         [0023]    The wire connecting the junction box to the indicator panel is a mother cable, and wherein the mother cable surrounds a plurality of connection wires, each of the connection wires being coupled to one of the plurality of flow indicator sensors and one of the indicators. 
         [0024]    The apparatus further includes a cable having one end coupled to the indicator panel and another end configured to be coupled to a battery to provide power to the indicator panel. 
         [0025]    Each flow indicator sensor has a cable coupled thereto that has a connector configured to mate with a corresponding connector coupled to a respective one of the wires. 
         [0026]    The indicator panel further includes, a power switch, indicia identifying each of the plurality of applicators, and one or more connectors configured to couple to the wires. 
         [0027]    Each flow indicator sensor includes a body having a first end configured to be coupled to the manifold, a second end configured to be coupled to one of the plurality of lines, and an axially extending cavity, a reed switch coupled to the body, and a poppet including a poppet body and a magnet disposed in the poppet body, the poppet being biased in a first position and being configured to be moved from the first position to a second position by fluid flowing through the axially extending cavity to activate/deactivate the switch. 
         [0028]    The body has an inner wall defining the axially extending cavity, and wherein the wall includes a plurality of flutes that allow flow through the cavity around the poppet. 
         [0029]    The flutes have a progressively larger flow area extending from a first end of the cavity to a second end of the cavity. 
         [0030]    According to still another aspect of the invention, a system for delivering fluid to a field using an agricultural implement is provided. The system includes a plurality of flow indicator sensors, each flow indicator sensor being connectable between a manifold and an applicator and configured to provide an output indicative of whether or not fluid is flowing through the sensor at a prescribed rate, an indicator panel for receiving the outputs from of the plurality of flow indicator sensors and for providing at least one of a visual or an audio indication to an operator based on the outputs, a junction box, a plurality of connection cables, each connection cable connecting one of the plurality of flow indicator sensors to the junction box, and a mother cable connecting the junction box to the indicator panel. 
         [0031]    According to a further aspect of the invention, a method for detecting an interruption in fluid flow from a fluid source to one or more applicators of a plurality of applicators and for notifying an operator of the interruption is provided. The method includes directing fluid from the fluid source through a plurality axially extending cavities of a plurality of flow indication sensors corresponding to respective applicators, detecting if the fluid is flowing through the plurality of flow indication sensors at a prescribed rate, and providing at least one of a visual or an audio indication via indicators corresponding to respective applicators if the fluid is flowing through one or more of the flow indication sensors below the prescribed rate, wherein if the fluid is flowing through one of the axially extending cavities at the prescribed rate, a magnet in the axially extending cavity is moved from a first position to a second position to activate a reed switch, thereby deactivating the corresponding indicator, and wherein if the fluid is flowing through one of the axially extending cavities below the prescribed rate, the magnet in the axially extending cavity is moved to the first position thereby deactivating the reed switch and activating the corresponding indicator. 
         [0032]    The foregoing and other features of the invention are hereinafter described in greater detail with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0033]      FIG. 1  is a schematic view of an agricultural distribution system; 
           [0034]      FIG. 2  is a schematic view of an exemplary agricultural distribution system according to the invention; 
           [0035]      FIG. 3  is a front view of an exemplary indicator panel according to the invention; 
           [0036]      FIG. 4  is a side cross-section view of an exemplary flow indication sensor according to the invention showing a poppet in a first position. 
           [0037]      FIG. 5  is a perspective cross-sectional view of the exemplary flow indication sensor showing the poppet in the first position. 
           [0038]      FIG. 6  is a side cross-sectional view of the exemplary flow indication sensor showing the poppet in a second position. 
           [0039]      FIG. 7  is a perspective cross-sectional view of the exemplary flow indication sensor showing the poppet in the second position. 
           [0040]      FIG. 8  is a side cross-section view of another exemplary flow indication sensor according to the invention showing a shuttle in a first position. 
           [0041]      FIG. 9  is a perspective cross-sectional view of the exemplary flow indication sensor showing the shuttle in the first position. 
           [0042]      FIG. 10  is a side cross-sectional view of the exemplary flow indication sensor showing the shuttle in a second position. 
           [0043]      FIG. 11  is a perspective cross-sectional view of the exemplary flow indication sensor showing the shuttle in the second position. 
       
    
    
     DETAILED DESCRIPTION 
       [0044]    The principles of the present application have particular application to agricultural systems for delivering a fluid, such as liquid anhydrous ammonia, to a field and for detecting an interruption in the flow of the fluid through applicators in a tool bar, and thus will be described below chiefly in this context. It will of course be appreciated, and also understood, that the principles of the invention may be useful in other fluid applications where it is desirable to monitor the flow of fluid through a conduit. 
         [0045]    Referring now in detail to the drawings and initially to  FIG. 1 , a vehicle  10 , such as a tractor, is shown connected to a tool bar  12 , which is coupled to a nurse tank  14  carried on a frame  16 . The vehicle  10  includes a cab  18  having a control station  20  and a control panel  22 . Lines  24  may connect the control panel  22  to a flow meter  26  to display a flow rate on the control panel and lines  28  may connect the control panel  22  to a flow regulator  30 . 
         [0046]    The nurse tank  14  may be any suitable tank that contains a fluid, such as pressurized liquid anhydrous ammonia. The tank  14  includes a withdrawal valve  32  through which the liquid exits the tank  14 . The withdrawal valve  18  is coupled to the flow meter  26  by a suitable connector  34 , and the flow meter  26  is coupled to a valve  36 . The valve  36  is coupled to a line  38 , such as a hose by a suitable connector, and the hose  38  is coupled to the tool bar  12 . 
         [0047]    The tool bar  12  includes a frame  40  coupled to the frame  16  and the vehicle  10 , and a plurality of applicators  42 , herein referred to as knives for tilling soil. The anhydrous ammonia is delivered from the nurse tank  14  through the hose  38  to a manifold  44  of the tool bar  12 . An inline filter  46  ( FIG. 2 ) may be provided between hose  38  and the manifold  44 . The fluid is then delivered from the manifold  44  to lines  48 , such as flexible hoses, extending from the manifold  44  to each knife  42  to distribute the anhydrous ammonia into the soil to serve as fertilizer. 
         [0048]    Turning now to  FIG. 2 , an exemplary system for delivering fluid to the field is illustrated generally at reference numeral  50 . The system  50  includes the plurality of laterally spaced knives  42 , the manifold  44  connectable to a source of fluid, such as the nurse tank  14 , the plurality of lines  48  connecting the manifold  44  to the knives  42 , a plurality of flow indicator sensors  52 , and an indicator panel  54 . 
         [0049]    The plurality of flow indicator sensors  52 , which will be discussed in detail below, provide an output to the indicator panel  54  indicative of whether or not fluid is flowing through the sensor at a prescribed rate. In this way, an operator may be notified of which knife  42  has a restriction, thereby preventing striping, which is characterized by rows of crops appearing malnourished and producing less crop yield due to the flow of anhydrous ammonia being restricted. 
         [0050]    Each of the plurality of flow indicator sensors  52  is connectable between the manifold  44  and a respective one of the plurality of lines  48 . Each flow indicator sensor  52  may be connected to the respective line  48  in any suitable manner, for example, each sensor  52  may be coupled to a line  56 , which is coupled to a suitable electrical connector  58 . The connector  58  is configured to mate with a corresponding connector (not shown) that is coupled to a wire  90 . In this way, the length of the lines  48  may be adjusted depending on a distance the respective knives  42  are from the manifold  44 . 
         [0051]    Referring now to  FIGS. 2 and 3 , the indicator panel  54  is provided for receiving the outputs from the plurality of flow indicator sensors  52 , for example as signals, and for providing at least one of a visual or an audio indication to an operator based on the signals. The indicator panel  54  includes a power switch  70  for turning the indicator panel  54  on/off, a plurality of indicators  72  each corresponding to one of the flow indicator sensors  52 , indicia  74  identifying respective flow indicator sensor  52  connected to respective indicators  72 , mounting holes  76 , mother cable connectors  80 , and a power connector  82 . The mounting holes  76  are provided on flanges  78  for mounting the indicator panel  54  in the cab of the vehicle  10 , for example in front of an operator using suitable fasteners. The power connector  82  are provided for connecting the indicator panel  54  to a power source, such as a battery  84  of the vehicle  10  via a cable  86 . 
         [0052]    The plurality of indicators  72  may be lights, such as light-emitting diodes, corresponding respectively to one of the flow indicator sensors  52 . When the fluid flowing through the flow indicator sensors  52  is below the prescribed rate, for example, through the sensor  52  coupled to the indicator  72  identified by the number  8  in  FIG. 3 , the indicator  72  may provide a visual indication to the operator. The visual indication notifies the operator that there is a clog in the knife  42  connected to the indicator  72  identified by the number  8 , thereby allowing the operator to stop the vehicle  10  and clear the clog. 
         [0053]    The plurality of indicators  72  are respectively coupled to the plurality flow indicator sensors  52  by respective wires  90 . The wires  90  may directly couple the flow indicator sensors  52  to the indicators  72  or be coupled to a junction box  92 , for example. As shown in  FIG. 2 , the wires  90  may have one end coupled to respective flow indicator sensors  52  and another end coupled to the junction box  92 . The wires  90  are connected in the junction box in any suitable manner to a mother cable  94 , which is coupled to the mother cable connectors  80 . 
         [0054]    The mother cable  94  may be directly coupled to the mother cable connectors  80  or be coupled to a cable  96  in any suitable manner, which is coupled to the connectors  80  in any suitable manner. The cable  96  may be coupled to the mother cable connectors  80  and extend, for example, to an exterior of the cab  18  of the vehicle  10  to allow the mother cable  94  to be conveniently connected/disconnected from the cable  96 . The mother cable  94  and the cable  96  may enclose a respective plurality of wires that correspond to the wires  90  to couple the flow indicator sensors  52  to the respective indicators  72 . 
         [0055]    Turning now to  FIGS. 4-7 , one of the plurality of flow indicator sensors  52  is illustrated in detail. The flow indicator sensor  52  includes a body  110 , a switch  112 , a poppet  114 , and a resilient member  116 . The body  110  may be made of any suitable material, such as aluminum and has a first end  118  configured to be coupled to the manifold  44 , a second end  120  configured to be coupled to one of the plurality of lines  48 , an axially extending cavity  122  defined by an inner wall  124  of the body  110 , and a plurality of flutes  126  in the inner wall  124  extending at least partially along a length of the cavity  122 . The first and second ends  118  and  120  may be coupled to the manifold  44  and line  48 , respectively, in any suitable manner, for example the first end  118  may have a male threaded portion that mates with a female threaded portion on the manifold  44  and the second end  120  may have a female threaded portion that mates with a male threaded portion on the line  48 . The flutes  126  have a flow area that increases from a first end of the flute near the first end  118  of the body  110  to a second end of the flute near the second end  120 . 
         [0056]    The switch  112  is disposed in a recess  128  in the body  110  and coupled to the body  110  in any suitable manner, such as by a sleeve  130  which may be secured to the body  110  in any suitable manner, such as by shrink fitting. The switch  112  may be any suitable switch, such as a magnetic reed switch coupled to one of the plurality of lines  90  to provide the output to the respective indicator  72 . 
         [0057]    The switch  112  may be activated/deactivated by movement of the poppet  114  from a first position to a second position. The poppet  114  is disposed in the axially extending cavity  122  and biased in the first position by the resilient member  116 , which may be any suitable member such as a spring that is retained in the cavity by a retainer  132 , such as a retainer ring. A washer  134  may also be included that serves as a seat for the resilient member  116 . The retainer  132  may abut a backside of the washer  134  to retain the resilient member  116  and washer  134 . The poppet  114  includes a body  140  which may be made of any suitable material, such as polytetrafluoroethylene, a magnet  142  disposed in a bore  144  in the body  140 , and a retainer  146 , such as a retainer screw secured in the bore  144  to retain the magnet  142 . The retainer  146  is secured to the bore  144  in any suitable manner, such as by threads  148  that mate with threads  150  in the bore  144 . 
         [0058]    When the poppet  114  is in the first position shown in  FIGS. 4 and 5 , an end of the poppet  114  closest the first end  118  of the body  110  abuts a shoulder  152  in the axially extending cavity  122 . The shoulder  152  prevents the poppet  114  from advancing further towards the first end  118 . When the poppet  114  is seated against the shoulder  152 , the fluid is flowing through the axially extending cavity  122  below the prescribed rate, such as no flow or low flow, and thereby the switch  112  is deactivated and the indicator  72  corresponding to the flow indicator sensor  52  indicates to the operator that fluid is flowing through cavity  122  below the prescribed rate, for example by activating the light-emitting diode. This may occur before the operator has begun use of the tool bar  12 , when there is a clog in the knife  42  corresponding to the flow indicator sensor  52 , a broken supply line, etc. 
         [0059]    When fluid from the manifold  44  flows through the axially extending cavity  122  above the prescribed rate, the fluid moves the poppet  114  to the second position against the force of the resilient member  116 , as shown in  FIGS. 6 and 7 . As the poppet  114  is moved to the second position, the magnet  142  activates the switch  112  and the indicator  72  corresponding to the flow indicator sensor  52  indicates to the operator that fluid is flowing through the cavity  122 , for example by deactivating the light-emitting diode. The fluid flowing through the cavity  122  flows around the poppet  114  through the flutes  126 . 
         [0060]    By providing the flutes  126  with progressively larger flow areas from one end to another, the flow indicator sensor  52  can be more sensitive at lower flow rates and reduce the pressure drop across the poppet  114  at higher flow rates due to the fact that the flutes  126  flow area gets larger around the poppet  114  as the poppet  114  moves against the resilient member  116 . The flute  126  configuration also allows for stronger resilient members  116  to be used, which increases the resilient members  116  resistance to malfunction due to debris in the axially extending cavity  122  at lower flow rates. 
         [0061]    Referring now to the operation of the system in detail, when the withdrawal valve  32  is closed, for example when the tool bar  12  is elevated, the fluid in the nurse tank  14  does not flow through the plurality of flow indicator valves  52 , and therefore the reed switch  112  is not activated and the plurality of indicators  72  indicate to operator the flow is below the prescribed rate, for example by lighting all of the light-emitting diodes. 
         [0062]    When the tool bar  12  is lowered so that the unrestricted knives  42  enter the soil, the withdrawal valve  32  is fully opened and the fluid flows through the flow indicator sensors  52  above the prescribed rate. The fluid moves the poppets  114  to their second positions, thereby activating the reed switches  112  and providing an indication to the operator that the flow is above the prescribed rate, for example by turning off the light-emitting diodes. 
         [0063]    As the vehicle  10  moves down a field, the fluid is delivered to the soil through via the knives  42 , and the operator may view the indicator panel  54  to determine if flow to any of the knives  42  becomes interrupted. If the flow of fluid through one or more of the flow indicator sensors  52  becomes interrupted, the corresponding indicators  72  will light up to notify the operator that there is an interruption. In an embodiment, the operator can then toggle optional switches, which may be the indicators  72  or associated with the respective indicators  72  to a no flow position, which will turn the indicators  72  off. 
         [0064]    Once the operator stops the vehicle  10  and shuts off the flow of fluid to the tool bar  12 , such as by closing the withdrawal valve  32 , the operator can remove the interruptions, such as by unclogging the clogged knifes  42 . With the flow shut off, the indicators  72  will light up except for the indicators  72  that were toggled to the no flow position. In this way, the operator can be reminded of which flow indicator sensor  52  showed and interruption. When the operator resumes delivering fluid to the soil, the operator can toggle the switches associated with the previously clogged indicators  72  from the no flow position to allow for the respective flow indicator sensors  52  to be monitored. 
         [0065]    Turning now to  FIGS. 8-11 , an exemplary embodiment of the flow indicator sensor is shown at  252 . The flow indicator sensor  252  is substantially the same as the above-referenced flow indicator sensor  52 , and consequently the same reference numerals but indexed by  200  are used to denote structures corresponding to similar structures in the flow indicator sensor. In addition, the foregoing description of the flow indicator sensor  52  is equally applicable to the flow indicator sensor  252  except as noted below. Moreover, it will be appreciated upon reading and understanding the specification that aspects of the flow control valves may be substituted for one another or used in conjunction with one another where applicable. 
         [0066]    Referring to  FIG. 8 , one of the plurality of flow indicator sensors  252  is illustrated. The flow indicator sensor  252  includes a first body  310 , a switch  312 , a shuttle  314 , a resilient member  316 , and a second body  360 . The first body  310  has a first end  318  configured to be coupled to the manifold  44 , a second end  320  configured to be coupled to one of the plurality of lines  48 , an axially extending cavity  322 , a first plurality of radially outwardly extending channels  362 , a venturi  364 , a second plurality of radially outwardly extending channels  366  downstream of the channels  362  and the venturi  364 , and a diverging nozzle  368 . 
         [0067]    The second body  360  includes an axially extending cavity  370  and a bore  372  in which the switch  312  is disposed. The second body  360  surrounds the first body  310  such that a chamber  374  is formed in the cavity  370  between the first and second bodies  310  and  360 , wherein the chamber  374  is fluidly connected to the channels  362  and  366 . The first and second bodies  310  and  360  are sealed to one another by suitable seals, such as o-rings  380  and  382 . The first body  310  is prevented from moving axially relative to the second body  360  in a first direction by a retainer  384  and in a second direction opposite the first direction by a shoulder  386  of the first body  310  that abuts a ledge  388  in the second body  360 . 
         [0068]    The shuttle  314  surrounds the first body  310  and is disposed in the chamber  374  with the resilient member  316 . The shuttle  314  is biased in the first position by the resilient member  316  and movable to a second position to activate/deactivate the switch  312 . Split rings  390  and  392  are provided in respective grooves in the body  340  of the shuttle  314  to close gaps between the first body  310  and the second body  360 , thereby enhancing the efficiency of the pressure differential across the shuttle  314 . The shuttle  314  is rotatable with the second body  360 , such as when the second body  360  rotates relative to the first body  310 , to provide a positive location of the magnet  342 , for example by an axial offset between the shuttle  314  and the first body  310 . 
         [0069]    When the shuttle  314  is in the first position shown in  FIGS. 8 and 9 , an end of the shuttle  314  closest the first end  318  of the body  310  abuts a shoulder  352  in the axially extending cavity  370 . When the shuttle  314  is seated against the shoulder  352 , the fluid is flowing through the axially extending cavity  322  below the prescribed rate, such as no flow or low flow, and the switch  312  is deactivated. The indicator  72  corresponding to the flow indicator sensor  352  thereby indicates to the operator that fluid is flowing through cavity  322  below the prescribed rate, for example by activating the light-emitting diode. 
         [0070]    When fluid from the manifold  44  flows through the axially extending cavity  322 , the fluid flows through the venturi  364 , where the fluid pressure is reduced and the velocity of the fluid is accelerated, and then through the divergent nozzle  368  where some of the energy lost is recovered and a pressure differential is created across the shuttle  314 . The pressure differential is communicated from the axially extending cavity  322  to the chamber  374  via the channels  362  and  366 . The resilient member  316  acts to resist the pressure differential across the shuttle  314  and to move the shuttle  314  to the first position when there is no flow in the axially extending cavity  322 . 
         [0071]    When fluid from the manifold  44  flows through the axially extending cavity  322  above the prescribed rate, the pressure differential causes the shuttle  314  to move to the second position against the force of the resilient member  316 , as shown in  FIGS. 10 and 11 . As the shuttle  314  is moved to the second position, the magnet  342  activates the switch  312  and the indicator  72  corresponding to the flow indicator sensor  252  indicates to the operator that fluid is flowing through the cavity  322  above the prescribed rate. The flow across the shuttle  314  is small in relation to flow through the axially extending cavity  322 , thereby reducing the chance that debris entrained in the fluid will enter the chamber  374  and cause sensor failure due to the shuttle  314  sticking in either the first or second position. 
         [0072]    Although the invention has been shown and described with respect to a certain embodiment or embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described elements (components, assemblies, devices, compositions, etc.), the terms (including a reference to a “means”) used to describe such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary embodiment or embodiments of the invention. In addition, while a particular feature of the invention may have been described above with respect to only one or more of several illustrated embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application.