Flow control valve virtual test rig
Flow control valve exercises and observations
♦ Select Flow>1_Variable Orifice Flow Control, from the drop-down list.
Experiment: Open circuit Flow/1_Variable Orifice Flow Control Valve. Move the test gauge over the orifice. Click on the variable orifice symbol. Change the restriction diameter from 10 to 6mm.
Question: What happens when the orifice size is changed from 10 to 6mm?
Experiment: Click on the variable orifice symbol and change the restriction diameter to 3mm.
Question: What happens when the orifice size is changed from 6 to 4mm?
Experiment: Drag the printer icon over the flow control valve. Reduce the orifice size in 1mm steps from 10 to 2mm pressing the large printer icon each time. Copy the results and plot the graph in a spreadsheet.
Question: Is the flow rate dependent on the pump flow?
Experiment: Reload circuit Flow/1_Variable Orifice Flow Control Valve. Click on the motor symbol. Change the load torque and observe the effect on the motor speed e.g. flow rate. Repeat with 6 and 4mm orifice.
Question: Is the flow rate sensitive to the load on the system?
Experiment: Click on the FCV symbol and select the meter-in option from the drop down box. Repeat the above test to identify any differences.
Question: What difference does a meter-in flow control valve make?
Experiment: Click on the FCV symbol and select the meter-out option from the drop-down box. Repeat the above test but also change the nominal size of the valve to the same size as the restrictor.
Question: What difference does a meter-out flow control valve make?
Pressure compensated flow control exercises
♦ Select Flow> 2_Pressure Compensated Flow Control, from the drop-down list.
Experiment: Open circuit Flow/2_Pressure Compensated Flow Control. Move the test gauge over the FCV. Click on the variable orifice symbol. Compare the settings to the variable orifice.
Question: What is the difference between setting a pressure compensated valve compared to a variable orifice?
Experiment: Open circuit Flow/2_Pressure Compensated Flow Control. Move the test gauge over the FCV. Click on the variable orifice symbol. Change the flow rate from 100 to 60L/min.
Question: What happens when the flow rate is changed from 100 to 60L/min?
Experiment: Compare input power required for the PC and orifice FCVs under the same operating conditions
Question: Is the pressure compensated FCV more energy efficient than the variable orifice FCV
Experiment: Drag the printer icon over the flow control valve. Reduce the flow rate from 100 to 10L/min, pressing the large printer icon at each step. Copy the results and plot the graph in a spreadsheet.
Question: Is the flow rate dependent on the pump flow?
Experiment: Click on the motor symbol. Change the load torque and observe the effect on the motor speed e.g. flow rate. Repeat with different FCV flow settings.
Question: Is the flow rate sensitive to the load on the system?
Meter-in flow control exercises and observations
♦ Select Flow> 3_Meter-In Flow Control, from the drop-down list.
Experiment: Open circuit Flow/3_Meter-In Flow Control. Click on the cylinder rod. Look at the loads on the cylinder and complete manual calculations to check what the pressures should be.
Question: What type of load does this circuit have?
Experiment: extend the cylinder and move the test gauge around the circuit to understand where pressure drop is that controls the flow.
Question: Where is the flow rate controlled while extending the cylinder?
Experiment: retract the cylinder and measure the pressures around the circuit. Knowing that hydraulics is a braking technology and we use pressure drops to control movement. Consider how this is achieved while retracting with meter-in controls.
Question: How is the flow rate controlled while retracting the cylinder?
Experiment: Click on the FCV valves to see the restrictor size. Observe the flow rates through the flow control valves.
Question: Will the same extend and retract speeds require the same size orifice.
Flow control valve exercises and observations
♦ Select Flow> 4_Meter-Out Flow Control, from the drop-down list.
Experiment: Open circuit Flow/4_Meter-Out Flow Control. Operate the directional valve and compare circuit pressures with those seen using the meter-in circuit.
Question: Compare meter-out with meter-in control?
Experiment: Extend the cylinder and move the test gauge around the circuit to understand the location of the pressure drop that controls the flow.
Question: Where is the flow rate controlled while extending the cylinder?
Experiment: Retract the cylinder and measure the pressures around the circuit. Knowing that hydraulics is a braking technology and we use pressure drops to control movement. Consider how this is achieved while retracting with meter-out controls.
Question: How is the flow rate controlled while retracting the cylinder?
Experiment: Move the test gauge to the cylinder body. Operate the raise solenoid then double click on the cylinder to freeze its movement (but not performance). Restrict the extend side FCV size until the pump flow rate starts to fall. Observe what happens to the pressures as the flow is restricted.
Question: Approximately what size restrictor is required start slowing the extend speed?
Experiment: Modify the physical parameter of the component in the circuit until you isolate what causes the pressure increase.
Question: What parameter causes the annulus pressure to exceed the maximum pump supply presssure?
Experiment: Modify the loads acting on the cylinder and observe how the pressures change. Reduce the loads to zero to note the worse case pressure intensification. Compare this figure with the figure you calculate using the cylinder areas.
Question: What other parameters affect the level of annulus intensification pressure and what is the worse case?
Diagnose the cylinder retraction instability
♦ Select Pressure> Diagnose 1 FCV POCheck
Experiment: Open Flow/Diagnose 1 FCV POCheck. extend and retract the cylinder. Change different parameters until you remove the judder and understand what causes it.
Question: Diagnose the cylinder retract instability?
Experimental Valve Testing
♦ Select Pressure> Test 1 Motor FCV
Experiment: Open Flow/Test 1 Motor FCV. Experiment with different loads, flows, pressure and valve configurations. Use the printer icon and button to take measurements and print out results via a spreadsheet.
Question: Experiment with a speed contol motor circuit?
Experiment: Click on the FCV valves to see the restrictor size. Observe the flow rates through the flow control valves.
Question: Record the bore and annulus pressures while extending and retracting the cylinder with different loads?