Basic Principles Test

Experiment with this basic hydraulic principles simulator

<< Module  Detail  Video  Experiment

Operate the valve with the slide bar and use the arrow buttons to explore each hydraulic principles

Basic Hydraulic Control Principles

Your browser does not support Canvas.

Suggested exercises and observations

1. Select step 1 (dropdown menu 1) Pilot pressure against a spool

• Adjust the pilot pressure on the spool by dragging the slide bar.

• Observe how the spool moves against the spring force.

2. Select step 2 (dropdown menu 2) Proportional valve spool position changes orifice size.

• Observe how the changing orifice size, changes the flow through the valve.

3. Select step 3 (dropdown menu 3) Load pressure on the gear motor.

• Change the load pressure and note how the pressure drop across the spool changes.

• Observe how the flow changes as the load pressure changes.

4. Select step 4 (dropdown menu 4) Spool clearance

• Consider what pressures will exist on either side of each spool lands.

• Use the pressure drop information to predict leakage flow rates and paths.

5. Select step 5 (dropdown menu 5) O-ring seals

• Consider how the friction from an O-ring will affect seal movement.

• Operate the spool to see the effects on hysteresis from the seal.

6. Select step 6 (dropdown menu 6) Restricted volumes

• Consider how an orifice that restricts flow from a chamber will affect seal movement.

• Operate the spool to see how the trapped volume affects its speed of movement.

Experiment 1: Directional valves are simply open or closed. Proportional valves have notches that control the orifice size.

Question 1: How is flow controlled in a directional valve circuit?

A fixed orifice will provide a fixed speed flow control. Provided the load pressure does not change.

Experiment 2: Flow is controlled by the size of a restriction and the pressure drop across it.

Question 2: Why does the flow change when the load pressure is changed?

Changing the load pressure also affects the pressure drop across the orifice. Assuming the supply pressure remains constant.

Experiment 3: Every spool valve has a small leakage due to the clearances between the bore and spool.

Question 3: What factors will affect the leakage flow rate in each spool valve?

The size of spool gap (based on manufacturing quality), the spool bore diameter, spool land length, pressure drop across the spool lands, dirt or damage around the spool.