Nozzle Flow Detection System

Abstract

With the use of a low cost microphone mounted at each nozzle, a sound signature of the nozzles may be captured and stored to be used as a continuous indicator of any changes in the flow rate of the nozzles. By measuring changes in sound at each nozzle, it is possible to determine the change in flow before a change in pressure manifests into a problem in the system. The change in sound will oftentimes be significant for plugged nozzles, or nozzles that have excessive wear and flow at too high of a rate. The invention has the advantage of being relatively low cost with ceramic microphones for example. and with little or no moving parts required. A closed loop control system may be included to compensate for nozzle degradation.

What is claimed is: 
     
         1 . A nozzle flow detection system comprising:
 a spray nozzle assembly providing an outlet for discharging a fluid;   a microphone positioned proximal to the outlet of the spray nozzle, the microphone being configured to communicate acoustic data corresponding to a discharge of fluid at the outlet;   a data structure holding a calibration measurement corresponding to a discharge of fluid at the outlet, the calibration measurement being derived from acoustic data provided by the microphone; and   a controller in communication with the microphone and the data structure, the controller being configured to receive a flow measurement corresponding to a discharge of fluid at the outlet, the flow measurement being derived from acoustic data provided by the microphone, and to compare the flow measurement to the calibration measurement to determine an error.   
     
     
         2 . The nozzle flow detection system of  claim 1 , wherein the controller is further configured to generate an alert when the error is greater than a predetermined tolerance. 
     
     
         3 . The nozzle flow detection system of  claim 2 , wherein the alert is visually displayed to an operator of a machine via a Human Machine Interface (HMI). 
     
     
         4 . The nozzle flow detection system of  claim 1 , wherein the fluid is a mixed fluid, and wherein the spray nozzle assembly further comprises first and second inlets for receiving first and second fluids, respectively, and a mixing chamber for mixing the first and second fluids to provide the mixed fluid. 
     
     
         5 . The nozzle flow detection system of  claim 4 , wherein the spray nozzle assembly further comprises an electronically controlled valve for controlling flow of the mixed fluid between the mixing chamber and the outlet. 
     
     
         6 . The nozzle flow detection system of  claim 5 , wherein the controller is in communication with the electronically controlled valve, and the controller is further configured to adjust the flow of the mixed fluid between the mixing chamber and the outlet according to the error. 
     
     
         7 . The nozzle flow detection system of  claim 6 , wherein the controller adjusts the flow of the mixed fluid when the error is greater than a predetermined tolerance. 
     
     
         8 . The nozzle flow detection system of  claim 6 , wherein the controller implements Proportional-Integral-Derivative controller (PID) control. 
     
     
         9 . The nozzle flow detection system of  claim 1 , wherein the spray nozzle assembly is one of a plurality of spray nozzle assemblies, and the data structure holds a plurality of calibration measurements corresponding to a discharge of fluid for each of the spray nozzle assemblies. 
     
     
         10 . The nozzle flow detection system of  claim 9 , wherein the controller is further configured to receive flow measurements corresponding to a discharge of fluid for each of the spray nozzle assemblies, and to compare the flow measurement to the calibration measurements to determine a plurality of errors. 
     
     
         11 . A self-propelled sprayer comprising:
 a chassis;   an operator cab supported by the chassis;   a Human Machine Interface (HMI) provided in the operator cab;   a fluid tank supported by the chassis;   a wing boom supported by the chassis, the wing boom having a plurality of spray nozzle assemblies coupled to the fluid tank via distribution lines, each spray nozzle assembly providing an outlet for discharging a fluid;   a plurality of microphones, each microphone being positioned proximal to an outlet of a spray nozzle assembly, each microphone being configured to communicate acoustic data corresponding to a discharge of fluid at the outlet;   a data structure holding calibration measurements corresponding to discharges of fluid at outlets of the plurality of spray nozzle assemblies, the calibration measurements being derived from acoustic data provided by the microphones; and   a controller in communication with the plurality of microphones and the data structure, the controller being configured to receive flow measurements corresponding to discharges of fluid at the outlets, the flow measurements being derived from acoustic data provided by the microphones, and to compare the flow measurements to the calibration measurements to determine errors.   
     
     
         12 . The self-propelled sprayer of  claim 11 , wherein the controller is further configured to generate an alert when an error is greater than a predetermined tolerance. 
     
     
         13 . The self-propelled sprayer of  claim 12 , wherein the alert is visually displayed to an operator of a machine via the HMI. 
     
     
         14 . The self-propelled sprayer of  claim 11 , wherein the fluid tank is a primary fluid tank holding a first fluid, and the distribution lines are primary distribution lines, and further comprising a secondary fluid tank supported by the chassis, the secondary fluid tank holding a second fluid,
 wherein the plurality of spray nozzle assemblies are coupled to the secondary fluid tank via secondary distribution lines, wherein the fluid is a mixed fluid, and wherein the spray nozzle assemblies further comprise a mixing chamber for mixing the first and second fluids to provide the mixed fluid.   
     
     
         15 . The self-propelled sprayer of  claim 14 , wherein the spray nozzle assemblies further comprise electronically controlled valves for controlling flow of the mixed fluid between the mixing chamber and the outlet. 
     
     
         16 . The self-propelled sprayer of  claim 15 , wherein the controller is in communication with the electronically controlled valves, and the controller is further configured to adjust the flow of the mixed fluid between the mixing chamber and the outlet according to the error. 
     
     
         17 . The self-propelled sprayer of  claim 16 , wherein the controller adjusts the flow of the mixed fluid when the error is greater than a predetermined tolerance. 
     
     
         18 . The self-propelled sprayer of  claim 16 , wherein the controller implements Proportional-Integral-Derivative controller (PID) control. 
     
     
         19 . A method for nozzle flow detection comprising:
 discharging a fluid at an outlet of a spray nozzle assembly;   using a microphone positioned proximal to the outlet to communicate acoustic data corresponding to the discharge of the fluid at the outlet;   holding a calibration measurement in a data structure, the calibration measurement corresponding to a discharge of fluid at the outlet, the calibration measurement being derived from acoustic data provided by the microphone; and   receiving a flow measurement corresponding to a discharge of fluid at the outlet, the flow measurement being derived from acoustic data provided by the microphone; and   comparing the flow measurement to the calibration measurement to determine an error.   
     
     
         20 . The method of  claim 19 , further comprising generating an alert when the error is greater than a predetermined tolerance.