Patent Publication Number: US-9885350-B2

Title: Water pump control system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. patent application Ser. No. 62/275,950, titled WATER PUMP CONTROL SYSTEM, filed Jan. 7, 2016, and U.S. patent application Ser. No. 62/118,619, titled WATER PUMP CONTROL SYSTEM, filed Feb. 20, 2015, the disclosures of which are hereby incorporated by reference in their entireties. 
    
    
     BACKGROUND 
     Vacuum excavation, which is also referred to as hydro excavation, is a process of excavating a soil with a jet of pressurized water and an air vacuum system. Pressurized water is injected to break up and cut soil while the air vacuum system operates to remove debris to a debris collection tank. 
     In certain applications, the pressure of discharging water should be limited to a certain level to ensure operators&#39; safety and prevent destruction of underlying infrastructure. Accordingly, vacuum excavation processes typically need to meet guidelines for maximum operating water pressures in different situations. Such guidelines are provided by several organizations, such as Gas Technology Institute (GTI), Occupational Safety and Health Administration (OSHA), and Technical Standards and Safety Authority (TSSA) in Ontario, Canada. Operators of vacuum excavation equipment are required to operate the equipment at a proper water pressure for a given circumstance. Operators are typically responsible for selecting a nozzle connected to a water pump and manipulating a water pump controller to properly set the water pump to a safe water pressure. 
     SUMMARY 
     In general terms, this disclosure is directed to a water pump control system. In one possible configuration and by non-limiting example, the water pump control system includes a control circuit for controlling a hydraulic actuation circuit configured to control a water pump circuit such that a water pressure produced by the water pump circuit does not exceed a desired water pressure. Various aspects are described in this disclosure, which include, but are not limited to, the following aspects. 
     In general, the control circuit operates to receive a desired water pressure from an operator of the system and monitor a water pressure generated by the water pump. The control circuit may operate to compare the desired water pressure and the monitored water pressure to generate the control signal to control the hydraulic actuation circuit, which then adjusts the operation of the water pump circuit. In certain examples, the hydraulic actuation circuit includes a proportional hydraulic valve, and the control circuit controls a water pump speed by monitoring a water pressure and adjusting a control signal (e.g., electric current) flowing into the proportional valve to meet the desired water pressure set by an operator. The control circuit may include a pressure transducer mounted to the water pump circuit to monitor the water pressure in real-time. 
     The water pump control system in accordance with the present disclosure can eliminate a bypass of water through a water pump unloader to reduce excessive heat in the water system. This results in lower maintenance costs and lower fuel costs. Further, the water pump control system may provide a user-friendly control of a water pressure generated by a water pump for excavating soil, while ensuring safety and preventing damage to underlying infrastructure. The water pump control system in accordance with the present disclosure operates to prevent a water pump circuit from generating a water pressure above a desired water pressure. In certain examples, the water pump control system enables an operator to set the desired water pressure for a given application. As such, the water pump control system in accordance with the present disclosure enables a vacuum excavation system to meet industry safety standards. Further, the water pump control system can increase the life of excavation equipment by preventing an excessive amount of flow that would otherwise be diverted over pressure relief valves commonly used in the vacuum excavation equipment. 
     One aspect is a method of controlling a water pump. The method may include: receiving a user input of a desired water pressure for the water pump; controlling a hydraulic actuation circuit to actuate the water pump at the desired water pressure; monitoring a water pressure generated by the water pump; comparing the water pressure with the desired water pressure; and if the water pressure is different from the desired water pressure, controlling the hydraulic actuation circuit to operate the water pump to adjust the water pressure to meet the desired water pressure. 
     Another aspect is a system for controlling a water pump to inject pressurized water. The system may include a hydraulic actuation circuit configured to actuate the water pump, and a control circuit configured to monitor a water pressure generated by the water pump and control the hydraulic actuation circuit. The control unit is configured to control the hydraulic actuation circuit to operate the water pump to adjust the water pressure not to exceed a desired water pressure. 
     Yet another aspect is a vacuum excavation vehicle. The vehicle may include a water pump circuit configured to produce a jet of pressurized water and inject the pressurized water to soil for excavation, a hydraulic actuation circuit configured to actuate the water pump circuit, and a control circuit configured to receive a desired water pressure and monitor a current water pressure produced by the water pump circuit. The control circuit is configured to control the hydraulic actuation circuit based upon a comparison between the desired water pressure and the current water pressure to adjust the hydraulic actuation circuit to operate the water pump circuit to meet the desired water pressure. 
     The above features and advantages and other features and advantages of the present teachings are readily apparent from the following detailed description of the best modes for carrying out the present teachings when taken in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Non-limiting and non-exhaustive embodiments are described with reference to the following figures, which are not necessarily drawn to scale, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified. 
         FIG. 1  is a side view of an example vacuum excavation vehicle. 
         FIG. 2  is another side view of the vacuum excavation vehicle of  FIG. 1 . 
         FIG. 3  is a top view of the vacuum excavation vehicle of  FIG. 1 . 
         FIG. 4  is a schematic block diagram of a water pump control system of  FIG. 1 . 
         FIG. 5  is a schematic diagram of an example water pump control system of  FIG. 4 , illustrating example elements of a water pump circuit, a hydraulic actuation circuit, and a control circuit. 
         FIG. 6  is a flowchart illustrating an example method of operating a control device of  FIG. 5 . 
         FIG. 7  is an example hydraulic circuit diagram of the water pump control system of  FIG. 5 . 
         FIG. 8  illustrates an exemplary architecture of a computing device that can be used to implement aspects of the present disclosure, including the control device of  FIG. 5 . 
         FIG. 9  a schematic diagram of another example water pump control system of  FIG. 4 . 
         FIG. 10  is a schematic view of an example water pump of  FIG. 9 . 
         FIG. 11  is an example hydraulic circuit diagram of the water pump control system of  FIG. 9 . 
     
    
    
     DETAILED DESCRIPTION 
     Various embodiments will be described in detail with reference to the drawings, wherein like reference numerals represent like parts and assemblies throughout the several views. 
     Referring to  FIGS. 1-3 , an example vacuum excavation vehicle  100  is described, employing a water pump control system in accordance with the present disclosure.  FIG. 1  is a side view of an example vacuum excavation vehicle  100 ,  FIG. 2  is another side view of the vacuum excavation vehicle  100  of  FIG. 1 , and  FIG. 3  is a top view of the vacuum excavation vehicle  100  of  FIG. 1 . 
     In some embodiments, the vehicle  100  can include a water tank  102 , a water pump control system  104 , a control panel  106 , a fan drive system  108 , a boom and vacuum hose  110 , a cyclone separator  112 , a debris collection tank  114 , and a water heating system  116 . 
     The vehicle  100  includes a water pump system for injecting a jet of pressurized water to soil to break it up and remove debris by air suction. As described below, the vehicle  100  is equipped with a water pump circuit  202  ( FIG. 4 ) to generate pressurized water that is then injected for digging soil. The pressurized water provides a working force to break up and cut the soil. One example of the vehicle  100  is Vactor HXX Hydroexcavator available from Vactor Manufacturing, Inc. (Streator, Ill.). 
     A water tank  102  operates to contain water that flows into a water pump  224  ( FIG. 5 ) that is used to generate pressurized water. The water tank  102  can be made of, for example, polyethylene (HDPE) or stainless steel. In some embodiments, polyethylene is preferable to stainless steel in making the water tank  102  because a polyethylene water tank can retain heat longer than a stainless steel tank, reducing a likelihood of freezing in harsh winter conditions. 
     A water pump control system  104  operates to control a water pump circuit  202  ( FIG. 4 ) to produce a desired water pressure set by an operator. An example water pump control system  104  is illustrated and described in more detail with reference to  FIGS. 4-7 . 
     A control panel  106  is configured to enable an operator to interact with several operative elements in the vehicle  100 , such as the water pump control system  104 . In the illustrated example, the control panel  106  is contained in a control box that is located curbside of the vehicle  100  for easy access and efficient operation. The control box can be made of aluminum for enhanced protection against environmental elements. The control panel  106  can provide various controls, such as a tachometer and hour meter for various components (e.g., a water pump and a fan), temperature indicators for various systems, a water pump circuit on/off switch, boom and body dump functions, an emergency stop button, and various other controls. The control panel  106  can communicate with a remote controller that is operated by an operator with either wireless or wired connection. In some embodiments, the control panel  106  includes a display screen to display various pieces of information, such as a water pressure of the water pump (e.g., a pressure of pressurized water injected through the hose  110 ). The control panel  106  includes a user interface  270  as illustrated and described with reference to  FIG. 5 . 
     A fan drive system  108  operates to actuate a fan to create a vacuum through the boom and vacuum hose  110  to draw debris into the debris collection tank  114 . 
     A boom and vacuum hose  110  is mounted on the top of the vehicle  100  and rotatable around the vehicle  100 . The boom and vacuum hose  110  is also extendable in length to cover a large working area. The boom and vacuum hose  110  has a digging lance  226  at a forward end thereof. An example digging lance  226  is illustrated and described with reference to  FIG. 5 . 
     A cyclone separator  112  operates with the fan drive system  108  to filter air, thereby increasing air-routing performance. 
     A debris collection tank  114  is configured to collect debris through the boom and vacuum hose  110  after the soil is cut and broken down by the pressurized water injected from the boom and vacuum hose  110 . In some embodiments, the debris collection tank  114  is made of high strength, low allow Ex-Ten 50 steel with corrosion resistance copper additive for longer component life. 
     A water heating system  116  operates to preheat water in the water tank  102  in cold weather conditions. 
     Referring to  FIGS. 4-7 , an example of the water pump control system  104  is described in more detail. 
       FIG. 4  is a schematic block diagram of the water pump control system  104  of  FIG. 1 . The water pump control system  104  can include a water pump circuit  202 , a hydraulic actuation circuit  204 , and a control circuit  206 . 
     The water pump circuit  202  operates to produce a jet of pressurized water  210  and inject the pressurized water  210  to soil for excavation. An example water pump circuit  202  is described and illustrated with reference to  FIG. 5 . 
     The hydraulic actuation circuit  204  operates to actuate the water pump circuit  202 . In some embodiments, the hydraulic actuation circuit  204  operates to receive a control signal  212  from the control circuit  206  and provide a pump driving force  214  to the water pump circuit  202  based upon the control signal  212 . An example hydraulic actuation circuit  204  is described and illustrated in more detail with reference to  FIG. 5 . 
     The control circuit  206  operates to control the hydraulic actuation circuit  204 , which subsequently controls the water pump circuit  202 , such that a water pressure produced by the water pump circuit  202  does not exceed a desired water pressure. 
     In some embodiments, the control circuit  206  operates to receive desired water pressure data  216  from an operator of the system. The desired water pressure data  216  includes information about a desired water pressure produced by the water pump circuit  202 . The desired water pressure can be a maximum water pressure for excavation processes that is permitted under a given application. In other embodiments, the data  216  can include a list of desired water pressures for different applications and can be stored in the control circuit  206  so that an operator does not need to independently set up a desired water pressure every time that the system is operated. 
     The control circuit  206  operates to monitor a status of the water pump circuit  202  and receive water pump condition data  218 . The water pump condition data  218  includes information about various conditions of the water pump circuit  202 . In some embodiments, the water pump condition data  218  contains information about a water pressure generated by the water pump circuit  202 . 
     The control circuit  206  operates to compare the desired water pressure data  216  and the water pump condition data  218  to generate the control signal  212 . When determining a difference between the desired water pressure and the current water pressure, the control circuit  206  generates the control signal  212  to control the hydraulic actuation circuit  204 , which, based on the control signal  212 , controls the operation of the water pump circuit  202  to adjust the current water pressure to the desired water pressure. An example operation of the control circuit  206  is described and illustrated in more detail with reference to  FIG. 6 . 
       FIG. 5  is a schematic diagram of an example water pump control system  104  of  FIG. 4 , illustrating example elements of the water pump circuit  202 , the hydraulic actuation circuit  204 , and the control circuit  206 . 
     In some embodiments, the water pump circuit  202  includes a water supply  222 , a water pump  224 , a digging lance  226 , and an injection nozzle  228 . 
     The water supply  222  includes the water tank  102  of the vehicle  100 . The water supply  222  contains water (W) and provides it to the water pump  224 . 
     The water pump  224  operates to move water (W) from the water supply  222  to the digging lance  226 . The water pump  224  can be of various types, such as plunger type water pumps. The water pump  224  is actuated by the pump driving force  214  generated by the hydraulic actuation circuit  204 . In this example, the water pump  224  is operated by mechanical action (e.g., torque) generated by a hydraulic motor  236  included in the hydraulic actuation circuit  204 . In some embodiments, the water pump  224  is configured to generate a water flow rate from 0 to 35 GPM. An input speed of the water pump  224  and a nozzle size can determine a water flow and pressure of the water pump  224 . As described herein, the control circuit  206  operates to control the water pump speed by monitoring the water pressure and adjusting the control signal  212  (e.g., electric current) flowing into the proportional valve  234  to meet the desired water pressure set by an operator. 
     The digging lance  226  is attached at the forward end of the boom and vacuum hose  110  and configured to be placed on soil to be broken up and cut. 
     The injection nozzle  228  is attached to an end of the digging lance  226  and configured to build up a pressure of water therein until a jet of pressurized water  210  is produced and discharged therethrough. 
     With continued reference to  FIG. 5 , the hydraulic actuation circuit  204  includes a hydraulic pump  232 , a proportional hydraulic valve  234 , and a hydraulic motor  236 . 
     The hydraulic pump  232  is a mechanical source of power in the hydraulic actuation circuit  204  and converts mechanical power into hydraulic energy. In some embodiments, the hydraulic pump  232  is a power take-off (PTO) driven hydraulic pump. For example, the hydraulic pump  232  can have an input shaft that may be driven by, for example, a primary power plant or engine  252  ( FIG. 1 ) of the vehicle  100  and/or an auxiliary power plant or engine. The hydraulic pump  232  includes an inlet port  238  and an outlet port  241 . The inlet port  238  is connected to a first reservoir  240 , and the outlet port  241  is connected to the proportional hydraulic valve  234 . When the hydraulic pump  232  is in operation (i.e., as the input shaft of the hydraulic pump  232  is rotated), hydraulic fluid (F) is drawn from the first reservoir  240  through the inlet port  238  and discharged to the proportional hydraulic valve  234  through the outlet port  241 . The hydraulic pump  232  can be of various types, such as variable displacement pumps and positive displacement pumps. 
     The proportional hydraulic valve  234  operates to provide hydraulic fluid (F) to the hydraulic motor  236 . The proportional hydraulic valve  234  is configured to change an output (e.g., a volume or rate of flow) of hydraulic fluid (F) proportionally to an input of the control signal  212 . As a result, the hydraulic motor  236 , and thus the water pump  224 , are operated based ultimately upon the control signal  212 . In some embodiments, the proportional hydraulic valve  234  is configured as a proportional hydraulic flow control valve. In some embodiments, the control signal  212  is an electric current, and the proportional hydraulic valve  234  is configured to change an output flow rate of hydraulic fluid (F) proportionally to the electric current (i.e., the control signal  212 ) flowing thereto. The proportional hydraulic valve  234  is also referred to herein as an electro-proportional compensator. 
     The hydraulic motor  236  is mechanically coupled to the water pump  224  and actuates the water pump  224 . The hydraulic motor  236  is a mechanical actuator that converts pressure and flow of hydraulic fluid (F) into torque and angular displacement (i.e., rotation). The hydraulic motor  236  has an output shaft  242  that is directly coupled to an input shaft  244  of the water pump  224 . The hydraulic motor  236  has an inlet port  246  for receiving hydraulic fluid (F) from the hydraulic pump  232  through the proportional hydraulic valve  234 , and an outlet port  248  for discharging the hydraulic fluid (F) to a second reservoir  250 . As the hydraulic fluid (F) passes from the inlet port  246  to the outlet port  248 , the hydraulic motor  236  generates the pump driving force  214  and delivers the force  214  to the water pump  224  through the output shaft  242  of the hydraulic motor  236  and the input shaft  244  of the water pump  224 . The hydraulic pump  232  can be of various types, such as variable displacement motors and positive displacement motors. 
     Although the first reservoir  240  and the second reservoir  250  are separately provided in the illustrate example, the first and second reservoirs  240  and  250  can share a common reservoir, thereby defining a closed loop hydraulic circuit. 
     With continued reference to  FIG. 5 , the control circuit  206  can include a user interface  270 , a control device  272 , and a pressure transducer  274 . The control circuit  206  can be retrofitted to any water pump control system  104  employing the water pump circuit  202  and the hydraulic actuation circuit  204 . 
     The user interface  270  provides an interface for an operator to interact with the control device  272 . In some embodiments, the user interface  270  is included in the control panel  106  of the vehicle  100 . The user interface  270  is configured to receive a user input  280  from the operator to manage the control device  272 . The user interface  270  can be configured in various manners, such as switches, buttons, adjustable knobs, and keypads. In other embodiments, the user interface  270  can be configured at least partially as a touch-sensitive screen. The user interface  270  can also include a screen for displaying various pieces of information about the water pump control system  104  to an operator. For example, such information can include a status of the water pump  224  (e.g., a flow rate or pressure at the water pump  224 ), a water level of the water supply  222 , information about the user input  280 , and other information relating to the operation of the water pump control system  104 . 
     The user interface  270  is configured to allow an operator to set a maximum working water pressure (e.g., a desired water pressure) to meet required pressure limitations per industrial practices or facility requirements. Such a maximum water pressure (e.g., a desired water pressure) provides an upper limit of a water pressure and is used to control a water pressure output of the water pump  224 . In some embodiments, the control device  272  can have one or more default setting of water pressure limitations based upon industrial practices for various circumstances. Such default settings can be custom-configurable to tailor specific requirements. 
     In some embodiments, the user interface  270  can provide a flow control switch configured to enable an operator to select any pressure up to the maximum working water pressure (e.g., the desired water pressure) either set by the operator or by default. In some embodiments, the control circuit  206  is configured such that a click (either single or double click) on the flow control switch of the user interface  270  leads the water pump  224  to the maximum working water pressure (e.g., the desired water pressure). In other embodiments, the control circuit  206  is configured such that a click (either single or double click) on the flow control switch of the user interface  270  leads the water pump  224  to a water pressure selected by the operator that is lower than the maximum working water pressure (e.g., the desired water pressure). 
     In some embodiments, the user input  280  includes a water pump control command and a desired water pressure. The water pump control command can include a power on/off command for switching on or off the water pump control system  104  (including the water pump  224 ). For example, the user interface  270  provides a two-way switch or a button (either mechanical or on a touch-sensitive display screen) that enables an operator to turn on or off the system  104 . The desired water pressure is a water pressure generated by the water pump  224  that is selected by an operator, and is included in the desired water pressure data  216 . Once the operator sets the desired water pressure, the control device  282  operates the water pump  224  to produce the desired water pressure, and controls the water pump  224  not to produce a water pressure that exceeds the desired water pressure. Further, the control device  282  operates not to allow an operator to choose a desired water pressure that exceeds a maximum water pressure that is permitted for excavation processes under a given circumstance. 
     The control device  272  operates to monitor the user input  280  and provide the control signal  212 . In some embodiments, the control device  272  includes at least one Vansco Multiplexing Module (VMM). For example, the control device  272  can include three VMM&#39;s. 
     As described above, the user input  280  includes a power on/off command, which can be called a MultiFlow control input in practice. When an operator manipulates the user interface  270  (e.g., a switch of the user interface  270 ) to input a command to turn on the water pump control system  104  (e.g., switching on the water pump  224 ), the control device  272  operates to process the input and generate the control signal  212  to increase or decrease a water flow at the water pump  224 , thereby adjusting a water pressure of the pressurized water  210 . In some embodiments, the control signal  212  generated by the control device  272  includes one high side and one low side proportional current signals that are provided to the proportional valve  234  configured to adjust a flow of hydraulic fluid (F) into the hydraulic motor  236 , which provides a driving force to the water pump  224 . 
     Further, when an operator sets a desired water pressure through the user interface  270 , the control device  272  operates to process the input and send the control signal  212  to the proportional valve  234 , which then controls a flow of hydraulic fluid (F) into the hydraulic motor  236 . The hydraulic motor  236  actuates the water pump  224  to produce the desired water pressure set by the operator. 
     The control device  272  further operates to monitor a status of the water pump circuit  202  and receive the water pump condition data  218  in real-time. In some embodiments, the water pump condition data  218  contains information about a water pressure of the water pump  224 . As described below, the water pressure of the water pump  224  can be monitored by the pressure transducer  274 . 
     As such, the control device  272  is configured to receive the user input  280  including the desired water pressure data  216  and monitor the water pump condition data  218  in real-time. The control device  272  uses the user input  280  and the water pump condition data  218  to control a current water pressure of the water pump  224  at the desired water pressure set by an operator, or at a pressure not greater than the desired water pressure. In some embodiments, the control device  272  can consider information about the digging lance  226  and/or the nozzle  228  (e.g., types and sizes) to calculate the current water pressure of the pressurized water  210  injected therefrom. Such information about the digging lance  226  and/or the nozzle  228  can be provided by an operator through the user interface  270  and included in the user input  280 . An example method of operating the control device  272  is illustrated and described in more detail with reference to  FIG. 6 . 
     The pressure transducer  274  is arranged and configured to detect a water pressure of the water pump  224  in real-time. In some embodiments, the pressure transducer  274  is arranged at a gage port (e.g., an outlet port) of the water pump  224 , as illustrated in  FIG. 7 . In other embodiments, the pressure transducer  274  is configured to directly detect a pressure of the pressurized water  210  at the nozzle  228  of the digging lance  226 . 
     In some embodiments, the pressure transducer  274  is configured to be freeze-proof and provides a control range of 0 to 5,000 psi. When the pressure transducer  274  fails, the water pump control system  104  can still operate. However, in this case, the operator should set the maximum water pressure. 
       FIG. 6  is a flowchart illustrating an example method  300  of operating the control device  272 . 
     At operation  302 , the control device  272  receives a desired water pressure set by an operator through the user interface  270 . The desired water pressure is a water pressure of the water pump  224  that the operator wants to obtain from the water pump  224 . 
     At operation  304 , the control device  272  determines whether the desired water pressure set by the operator is greater than a maximum allowable water pressure under a subject application. The maximum allowable water pressure can be determined for operator&#39;s safety and for preventing destruction of underlying infrastructure for a particular application or circumstance and provided by various organizations, such as Gas Technology Institute (GTI), Occupational Safety and Health Administration (OSHA), and Technical Standards and Safety Authority (TSSA) in Ontario, Canada. If the desired water pressure set by the operator is greater than such a maximum allowable water pressure (“YES” at operation  304 ), the method ends such that the water pump circuit  202  is in inoperative condition. Otherwise (“NO” at operation  304 ), the method continues to operation  306 . 
     At operation  306 , the control device  272  determines whether the water pump control system  104  (e.g., the water pump circuit  202 , the hydraulic actuation circuit  204 , and/or the control circuit  206 ) is powered on or remains in operation. In some embodiments, the control device  272  monitors that the operator inputs a switch-on command through the user interface  270 . If it is determined that the system is instructed to be powered on (“YES” at operation  306 ), the method continues on at operation  308 . Otherwise (“NO” at operation  306 ), the method ends such that the operation of the water pump circuit  202  stops. 
     At operation  308 , the control device  272  monitors a current water pressure of the water pump  224  in real-time through the pressure transducer  274 . 
     At operation  310 , the control device  272  operates to compare the current water pressure and the desired water pressure. In some embodiments, the current water pressure, the desired water pressure, and/or the comparison thereof can be displayed on the user interface  270  for the operator&#39;s reference. As described herein, the comparison between the current water pressure and the desired water pressure is used to generate the control signal  212  to adjust electric current that is provided to the proportional valve  234 , which accordingly adjusts a flow of hydraulic fluid (F) into the hydraulic motor  236 . 
     At operation  312 , the control device  272  determines whether the current water pressure is the same as the desired water pressure. If it is determined that the current water pressure matches the desired water pressure (“YES” at operation  312 ), the method moves on to operation  314 . Otherwise (“NO” at operation  312 ), the method continues to operation  316 . 
     At operation  314 , the control device  272  operates to maintain the current operation of the proportional valve  234 . As a result, the operation of the water pump  224  remains consistent and does not change a pressure of the pressurized water  210 . The method then returns to the operation  306 . 
     At operation  316 , the control device  272  determines whether the current water pressure is greater than the desired water pressure. If it is determined that the current water pressure is greater than the desired water pressure (“YES” at operation  316 ), the method moves on to operation  318 . Otherwise (“NO” at operation  316 ), the method continues on at operation  320 . 
     At operation  318 , the control device  272  generates and sends the control signal  212  to control the proportional valve  234 , which subsequently controls the hydraulic motor  236 . In this case, the control device  272  can increase electric current flowing into the proportional valve  234  to increase a flow of hydraulic fluid (F) into the hydraulic motor  236 , thereby speeding up the water pump  224  to increase a water pressure of the water pump  224  to meet the desired water pressure. Then, the method returns to the operation  306 . 
     At operation  320 , the control device  272  generates and sends the control signal  212  to control the proportional valve  234 , which subsequently controls the hydraulic motor  236 . In this case, the control device  272  can decrease electric current flowing into the proportional valve  234  to decrease a flow of hydraulic fluid (F) into the hydraulic motor  236 , thereby slowing down the water pump  224  to lower a water pressure of the water pump  224  to meet the desired water pressure. Once the operation  320  is done, the method returns to the operation  306 . 
     As such, the control device  272  operates to control electric current provided to the proportional valve  234  such that, when an operator sets a desired water pressure (not exceeding a maximum allowable pressure) through the user interface  270 , the water pump  224  is operated to automatically produce the pressurized water  210  at the desired water pressure. The operator can select any level of water pressure up to the maximum allowable pressure. Further, the operator does not need to continue to press a button on the control panel  106  until a water pressure of the water pump  224  reaches the desired water pressure set by the operator. Once the maximum allowable water pressure is reached, the control device  272  does not increase electric current flowing to the proportional valve  234  to prevent the operator to increase a water pressure greater than the maximum allowable water pressure. Accordingly, the control device  272  prevents excessive flow conditions at the water pump  224 . Therefore, the control circuit  206  utilizing the control device  272  and the pressure transducer  274  can eliminate an unloader and a water pressure relief that are typically used with the water pump  224  to relieve excess water pressure. 
     As described above, the control device  272  does not require an operator to maintain a switch or button to be depressed until the desired water pressure is reached. Once an operator simply selects a desired water pressure through the user interface  270  and input a command to turn on the system (e.g., by single or double tapping on a switch or button displayed on a touch-sensitive display screen of the user interface  270 ), the control device  272  operates to automatically increase electric current into the proportional valve  234  until the desired water pressure is achieved. 
     The control device  272  can maintain the desired water pressure of the water pump  224  regardless of whether the nozzle  228  of the digging lance  226  has different types or sizes. As described above, the control device  272  is configured to detect a current water pressure of the water pump  224  in real-time through the pressure transducer  274 , compares the current water pressure with the desired water pressure, and adjust electric current flowing into the proportional valve  234  based upon the comparison to increase or decrease the water pressure of the water pump  224  to meet the desired water pressure. This process does not depend on the types or sizes of the nozzle  228 . Therefore, the control device  272  does not require an operator of the system to consider the types or sizes of the nozzle  228  when operating the system. Further, the control device  272  can also compensate for both an increase in water pressure when an operator releases a trigger of the digging lance  226  and a decrease in water pressure when an operator depresses the trigger of the digging lance  226 , thereby maintaining the desired water pressure. 
     In some embodiments, the vehicle  100  includes multiple operator stations that allow one or more operators to perform excavation processes simultaneously with water from the common water pump  224 . The control device  272  can continuously monitor and maintain a water pressure from the water pump  224  regardless of whether all or some of the multiple operator stations are in use. By way of example, the vehicle  100  can have two operation stations, and two operators can manipulate the two operations in different manners. For example, the control device  272  can maintain a same desired water pressure even if the operators use different sizes of nozzles. Even if one of the operators releases a trigger of a digging lance  226 , which generates excess water flow, the control device  272  can maintain such a desired water pressure and eliminate the need of an unloader valve to bypass the excess water flow. Where only one operator station has been in use and the other operator station has just been turned on, water flow can be insufficient for both operators. The control device  272  can monitor such insufficiency of water flow and automatically control the water pump  224  to a desired water pump as described above. Without the control device  272 , one or both of the operators would have to manually adjust a water flow at the water pump  224  to compensate for the other operator. As such, the control device  272  can automatically compensate for pressure fluctuations of the water pump  224  resulting from actuating or releasing triggers of digging lances  226 . 
       FIG. 7  is an example hydraulic circuit diagram of the water pump control system  104  of  FIG. 5 . The hydraulic circuit diagram as illustrated in  FIG. 7  shows one example of the water pump control system  104 . Other embodiments of the water pump control system  104  are also possible with different mechanical, electrical, and/or hydraulic components and different combinations thereof. 
       FIG. 8  illustrates an exemplary architecture of a computing device that can be used to implement aspects of the present disclosure, including the control device  272 . The computing device illustrated in  FIG. 8  can be used to execute the operating system, application programs, and software modules (including the software engines) described herein. By way of example, the computing device will be described below as the control device  272 . To avoid undue repetition, this description of the computing device will not be separately repeated herein for each of other computing devices that can be used in the water pump control system  104  and/or the vehicle  100 , but such devices can also be configured as illustrated and described with reference to  FIG. 8 . 
     The control device  272  includes, in some embodiments, at least one processing device  402 , such as a central processing unit (CPU). A variety of processing devices are available from a variety of manufacturers, for example, Intel or Advanced Micro Devices. In this example, the control device  272  also includes a system memory  404 , and a system bus  406  that couples various system components including the system memory  404  to the processing device  402 . The system bus  406  is one of any number of types of bus structures including a memory bus, or memory controller; a peripheral bus; and a local bus using any of a variety of bus architectures. 
     Examples of computing devices suitable for the control device  272  include a desktop computer, a laptop computer, a tablet computer, a mobile computing device (such as a smart phone, an iPod® or iPad® mobile digital device, or other mobile devices), or other devices configured to process digital instructions. 
     The system memory  404  includes read only memory  408  and random access memory  410 . A basic input/output system  412  containing the basic routines that act to transfer information within control device  272 , such as during start up, is typically stored in the read only memory  408 . 
     The control device  272  also includes a secondary storage device  414  in some embodiments, such as a hard disk drive, for storing digital data. The secondary storage device  414  is connected to the system bus  406  by a secondary storage interface  416 . The secondary storage devices  414  and their associated computer readable media provide nonvolatile storage of computer readable instructions (including application programs and program modules), data structures, and other data for the control device  272 . 
     Although the exemplary environment described herein employs a hard disk drive as a secondary storage device, other types of computer readable storage media are used in other embodiments. Examples of these other types of computer readable storage media include magnetic cassettes, flash memory cards, digital video disks, Bernoulli cartridges, compact disc read only memories, digital versatile disk read only memories, random access memories, or read only memories. Some embodiments include non-transitory media. Additionally, such computer readable storage media can include local storage or cloud-based storage. 
     A number of program modules can be stored in secondary storage device  414  or memory  404 , including an operating system  418 , one or more application programs  420 , other program modules  422  (such as the software engines described herein), and program data  424 . The control device  272  can utilize any suitable operating system, such as Microsoft Windows™, Google Chrome™, Apple OS, and any other operating system suitable for a computing device. 
     In some embodiments, a user provides inputs to the control device  272  through one or more input devices  426 . Examples of input devices  426  include a keyboard  428 , mouse  430 , microphone  432 , and touch sensor  434  (such as a touchpad or touch sensitive display). Other embodiments include other input devices  426 . The input devices are often connected to the processing device  402  through an input/output interface  436  that is coupled to the system bus  406 . These input devices  426  can be connected by any number of input/output interfaces, such as a parallel port, serial port, game port, or a universal serial bus. Wireless communication between input devices and the interface  436  is possible as well, and includes infrared, BLUETOOTH® wireless technology, 802.11a/b/g/n, cellular, or other radio frequency communication systems in some possible embodiments. 
     In this example embodiment, a display device  438 , such as a monitor, liquid crystal display device, projector, or touch sensitive display device, is also connected to the system bus  406  via an interface, such as a video adapter  440 . In addition to the display device  438 , the control device  272  can include various other peripheral devices (not shown), such as speakers or a printer. 
     When used in a local area networking environment or a wide area networking environment (such as the Internet), the control device  272  is typically connected to a data communications network through a network interface  442 , such as an Ethernet interface. Other possible embodiments use other communication devices. For example, some embodiments of the control device  272  include a modem for communicating across the network. 
     The control device  272  typically includes at least some form of computer readable media. Computer readable media includes any available media that can be accessed by the control device  272 . By way of example, computer readable media include computer readable storage media and computer readable communication media. 
     Computer readable storage media includes volatile and nonvolatile, removable and non-removable media implemented in any device configured to store information such as computer readable instructions, data structures, program modules or other data. Computer readable storage media includes, but is not limited to, random access memory, read only memory, electrically erasable programmable read only memory, flash memory or other memory technology, compact disc read only memory, digital versatile disks or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and that can be accessed by the control device  272 . Computer readable storage media does not include computer readable communication media. 
     Computer readable communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media. The term “modulated data signal” refers to a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, computer readable communication media includes wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, radio frequency, infrared, and other wireless media. Combinations of any of the above are also included within the scope of computer readable media. 
     The computing device illustrated in  FIG. 8  is also an example of programmable electronics, which may include one or more such computing devices, and when multiple computing devices are included, such computing devices can be coupled together with a suitable data communication network so as to collectively perform the various functions, methods, or operations disclosed herein. 
       FIG. 9  is a schematic diagram of another example water pump control system  104  of  FIG. 4 , illustrating example elements of the water pump circuit  202 , the hydraulic actuation circuit  204 , and the control circuit  206 . 
     As many of the concepts and features described with reference to  FIG. 9  are similar to the example shown in  FIG. 5 , the description with respect to  FIG. 5  is hereby incorporated by reference for this example. Where like or similar features or elements are shown, the same reference numbers will be used where possible. The following description will be limited primarily to the differences from the example of  FIG. 5 . 
     In the example of  FIG. 9 , the water pump control system  104  includes a single piston water pump  524 , which can replace the water pump  224 , the hydraulic pump  236 , and associated components, such as the shafts  242  and  244 . As described below, the single piston water pump  524  is configured as a double-acting position reciprocating pump, while the water pump  224  in  FIG. 5  is illustrated as a crankshaft driven, plunger-style reciprocating pump. 
     Similarly to the water pump  224 , the water pump  524  operates to move water (W) from the water supply  222  to the digging lance  226 . In this example, the water pump  524  includes a dual action, single piston water pump that is operated by the hydraulic actuation circuit  204 . One example of the water pump  524  is a Vactor JetRodder water pump, which is available by Vactor Manufaturing (Streator, Ill.). Other water pumps can also be used in other embodiments. An example structure of the water pump  524  is illustrated below with respect to  FIG. 10 . 
     As described herein, the control circuit  206  operates to control the water pump speed by monitoring a status of the water pump  524 , such as the water pressure and/or the piston position of the water pump  524 , and generating the control signal  212  (e.g., electric current) transmitted to the proportional valve  234  to meet the desired water pressure set by an operator through the user interface  270 . In some examples, the control signal  212  includes electric current that is adjusted and flows into the proportional valve  234 . In some embodiments, the control circuit  206  includes the pressure transducer  274  for monitoring the water pressure of the water pump  524 . In addition, the control circuit  206  further includes a position sensor  574 . In some embodiments, the position sensor  574  includes a linear position sensor. 
     As such, the water pump condition data  218  can include information about the water pressure of the water pump  524  monitored by the pressure transducer  274  and about the position of the piston of the water pump  524  monitored by the piston position sensor  574 . 
     Although the piston position sensor  574  is illustrated in  FIG. 9  to be included in the control circuit  206 , some embodiments of the piston position sensor  574  are attached to the water pump  224 . In other embodiments, the piston position sensor  574  is disposed in other locations. 
       FIG. 10  is a schematic view of an example of the single piston water pump  524  of  FIG. 9 . In this example, the water pump  524  includes a hydraulic cylinder  530  on one side of a sealed center block  532  and a water cylinder  534  on the other side. A single shaft  536  extends between the hydraulic cylinder  530  and the water cylinder  534  through the center block  532  and is provided with two piston heads  540  and  542  at the opposite ends of the shaft  536 . The shaft  536  is configured to reciprocate with a first piston head  540  disposed within the hydraulic cylinder  530  and a second piston head  542  disposed within the water cylinder  534 . The first piston head  540  defines a first hydraulic chamber  560  and a second hydraulic chamber  562  within the hydraulic cylinder  530 . Similarly, the second piston head  542  defines a first water chamber  564  and a second water chamber  566  within the water cylinder  534 . 
     The pump  524  operates to constantly load and expel hydraulic oil F to/from the hydraulic cylinder  530 , and accordingly load and expel water W to/from the water cylinder  534 . For example, when the hydraulic fluid F is supplied to the first hydraulic chamber  560  and discharged from the second hydraulic chamber  562  of the hydraulic cylinder  530 , the piston shaft  536  moves in a first direction D 1 , thereby discharging water from the second water chamber  566  and drawing water into the first water chamber  564  of the water cylinder  534 . When the hydraulic fluid F is supplied to the second hydraulic chamber  562  and discharged from the first hydraulic chamber  560 , the piston shaft  536  moves in a second direction D 2  opposite to the first direction D 1 , thereby discharging water from the first water chamber  564  and drawing water into the second water chamber  566 . 
     In one example, the single piston water pump  524  can accommodate the following water flows and pressures depending on a hose size. 
     
       
         
           
               
               
               
            
               
                   
               
               
                   
                 Flow and Pressure 
                 Hose Size 
               
            
           
           
               
               
               
            
               
                   
                 (GMP @ PSI) 
                 (Inches) 
               
               
                   
                   
               
            
           
           
               
               
               
            
               
                 40 
                 2500 
                 ¾ or 1 
               
               
                 50 
                 3000 
                 ¾ or 1 
               
               
                 60 
                 2000 
                 1 
               
               
                 60 
                 2500 
                 1 
               
               
                 70 
                 3000 
                 1 
               
               
                 80 
                 2000 
                 1 
               
               
                 80 
                 2500 
                 1 
               
               
                 100 
                 2000 
                 1¼ 
               
               
                 120 
                 2000 
                 1¼ 
               
               
                   
               
            
           
         
       
     
     The single piston water pump  524  includes a reduced number of moving elements by eliminating, such as the input and output shafts  242  and  244  as illustrated in  FIG. 5 . Further, the single piston water pump  524  allows a slow stroke, thereby reducing friction and providing longer field life with less maintenance. 
       FIG. 11  is an example hydraulic circuit diagram of the water pump control system  104  of  FIG. 9 . As illustrated, the water pump control system  104  can further include a pump control manifold  550  that is provided to regulate fluid flow to the single piston water pump  524 . 
     In some embodiments, the water pump control system  104  includes an accumulator. In other embodiments, the water pump control system  104  does not include an accumulator. In some embodiments, the water pump control system  104  includes one or more unloader valves. In other embodiments, the water pump control system  104  does not include an unloader valve. 
     With continued reference to  FIGS. 9-11 , the water pump control system  104  employs a hydraulic directional control valve (e.g., the proportional valve  234 ) to reverse the direction of the water pump when the water pump reaches the end of its stroke. The position sensor  574 , which can be configured as a linear position sensor, operates to provide feedback to the control device  272  regarding the position of the piston  536  within the water pump  524 . Based on the feedback on the piston position, the control device  272  electrically actuates the directional control valve to change the direction of movement of the piston  536  within the water pump  524 . The use of the position sensor  574  allows the water pump to achieve an increased stroke length while preventing the piston from hitting the end of the water pump. Hitting the end of the pump would otherwise cause pressure spikes, which are detrimental to the water system. Further, the use of the linear sensor can enable the system to obtain and present the status of water flow in real-time. This allows an operator to monitor water usage as well as the selected nozzle for excessive wear. 
     As described above, in accordance with an exemplary embodiment of the present disclosure, the water pump control system  104  includes the control device  282 , which, in some examples, includes three Vansco Multiplexing Modules (VMM), to monitor the system inputs and provide system outputs based on the inputs. The system inputs can include a momentary switch that, when actuated (for example, up or down), sends an input to either increase or decrease the water pump flow. This input is processed by the control device and can generate an output, which, for example, includes high-side and low-side proportional current drivers. The current drivers can be connected to the proportional hydraulic valve  234  (e.g., an electro-proportional compensator), which regulates the stroke of the hydraulic pump, to produce the requested oil flow to the water pump  524 . As such, an operator can use this system to set a pressure in the water pump. The system may include a pressure relief valve to relieve excess water flow in case of a failure to the electro-proportional compensator. 
     As described herein, the water pump control system  104  enables a user to select a desired water pressure. The system includes the user interface  270 , such as a selector switch, to set a target water pressure. The system further includes the pressure transducer  274  that can be placed in a gage port of the water pump to provide real-time pressure feedback to the control device  272 . The control device  272  uses the feedback to compare the actual system pressure to the target pressure. In some embodiments, the actual and target pressure readings can be displayed on the user interface  272  (e.g., a control panel display). The result of comparison can be used to control the current drivers that are connected to the electro-proportional compensator, which then provides hydraulic oil flow to the water pump  524 . This control feature can limit the current to the electro-proportional compensator so that the operator can use the switch to select any pressure up to the selected pressure. Once the selected pressure has been achieved, it will not allow the operator to increase the current to the electro-proportional compensator, thereby preventing the hydraulic pump from producing more flow than what is required to achieve the requested flow. As described above, the system also employs the linear position sensor  574  that monitors the piston position to allow a maximum stroke within the pump  524 . 
     The various examples and teachings described above are provided by way of illustration only and should not be construed to limit the scope of the present disclosure. Those skilled in the art will readily recognize various modifications and changes that may be made without following the example examples and applications illustrated and described herein, and without departing from the true spirit and scope of the present disclosure.