Check valve symbol simulation

Non-return valve virtual test rig

Exercises and observations

Check Valve Symbol Experiment

1. Select Directional>1_Check Valve Testing, from the drop-down list.

♦ Click on one of the blue circles to activate one solenoid.

♦ Click on both blue circles (the middle) to switch the spool valve.

♦ Click on the cylinder rod to reveal the load that is acting directly onto the cylinder bore

♦ Observe how, even though the load is trying to retract the cylinder, it is held in position by the check valve.

♦ Change the load direction on the cylinder rod to observe how it starts extending.

♦ Allow the cylinder to fall by opening the solenoid operated bypass valve. You will need to increase the load acting onto the cylinder.

2. Select Directional>2_Check Valve Rectifier, from the drop-down list.

♦ Operate the directional valve and observe when the check valves open and close to direct the flow through the variable orifice.

Consider1: Spring are often used in check valves to make sure the poppet closes when flow stops.

Question 1: What difference does the spring rating have on the upstream and downstream pressure?

A higher spring pressure generates a higher pressure before it opens and therefore greater energy loss. Most check valves can have a range of spring pressures, or even no spring at all. The spring rating should be written along side of the symbol.

Consider2: In the reverse flow, closed direction, the poppet will be closed and the pressure will increase to the maximum possible.

Question 2: What is the maximum possible pressure acting on a closed check valve?

Firstly the valve might see the supply pressure multiplied by the cylinder intensification ratio. But also shock loads onto the cylinder can create massive pressure peaks.

Check valve symbol simulation

Experiment with non-return check valves

Non-return valve virtual test rig

Exercises and observations