Pneumatic and Hydraulic Symbols Quiz

Document Purpose

• Intended to aid understanding and memorization of pneumatic, electro-pneumatic, and hydraulic symbols.
• Lists components used in the module.
• Some symbols require memorization; others must be understood for application.

Pure Pneumatic Symbols

Air Service Unit

• Consists of a filter, manual drain, pressure relief/reducing valve, and a pressure gauge.
• Prevents unwanted particles from entering the system.

Air Service Unit (Simplified)

• Same as the full air service unit, but smaller and takes up less space.

Two Pressure/AND Valve

• Requires two input signals simultaneously to produce an output signal on port two.

Shuttle/OR Valve

• Produces an output signal on port two if either the left or right port one is active.
• Output on port two occurs if both left and right ports are active.

One Way Restrictor Valve

• Compressed air applied to port one bypasses restriction, flowing directly from port one to port two.
• If compressed air is applied to port two, flow is directed through the restriction, slowing cylinder movement.

Compressed Air Supply

• This symbol represents a compressor.
• Users can adjust pressure and flow in simulated environments.

Single Acting Cylinder

• This type of actuator generates linear movement.
• It requires compressed air for extension and returns to its retracted position when air is removed.

Double Acting Cylinder (with Limit Switches)

• Has ports for extending and retracting.
• Includes limit switches (a0 and a1) that activate events upon full extension or retraction.

Quick Exhaust Valve

• Allows for faster cylinder retraction/extension.
• Typically has a restricted exhaust pathway, but port one is typically blocked during exhaust.

Variable Pressure Reducing/Relief Valve

• Automatically opens to release air when pressure exceeds the pre-set limit.
• This prevents pressure from overcoming a system's threshold.

Time Delay Valve (Normally Closed)

• Has a time delay before opening to allow compressed air to flow from port one to port two.
• Triggered by an air signal on port 12.
• Flow timing depends on flow restrictor settings.

Three Two Valve

• Three connections and two positions.
• Active port (right block) will block port one and connect exhaust (port three) to port two.
• Alternatively, active left block connects port one to port two, blocking exhaust.
• Similar principle applicable to five-two valve configurations.

Ways to Actuate/Operate Valves

• Mechanical, pneumatic, and electrical methods.

Roller Lever Actuation

• The actuation occurs when a cylinder retracts or extends.
• Often used for three-two valves or five-two valves.

Idle Return Roller Actuation

• Valve operation on either retract or extend stroke, not both, unlike roller lever valves.
• Actuation is not used in full extension or retraction; instead, it's for partial movements.

Pneumatic Actuation

• Valve is operated by a pneumatic signal on port 12.

Spring Actuation (Spring Return)

• Valve returns to its original position (rest position) via a spring when no active actuation is present on the left side.

Pushbutton Actuation

• Operated by a pushbutton.
• A spring brings it back to its original position (spring return).

Selector Switch (Detent Switch)

• Valve activated by a selector switch that continuously remains active until switched OFF.

Foot Pedal Actuated

• Operated by a foot pedal.
• This demonstrates mechanical actuation.

Electropneumatic Symbols

• Components with electrical and pneumatic connections; often shown separately in diagrams.
• Examples: Solenoid Actuated valves

Solenoid Actuated

• Electrically actuated valve that uses 24V DC.
• The electrical part is separate from the pneumatic part in diagrams.
• Valve becomes active with 24V applied.

Pressure Sensor

• Consists of a pneumatic part and an electrical part for sensing pressure.
• Operates a switch when the pressure reaches the pre-set amount.
• The electrical part, shown separately, is operated when pressure is reached.

Electric Symbols

• Relays, time delay relays, time-off delay relays, along with switches, pushbuttons, and limit switches.

Normal Relay

• Has a relay coil and associated contacts (shown visually to the right.)

Delay-on Timer

• Activating the relay coil results in a delayed switching of associated contacts

Delay-off Timer

• Switching the relay coil results in a delayed switching of associated contacts.
• Activating the coil sets off the time delay and stays on until the delay expires.

Pushbutton (Normally Open)

• A button that creates a connection when pressed.
• Contact breaks when the button releases.

Pushbutton (Normally Closed)

• A button that creates a break in a connection when pressed.
• Contact restores when the button releases.

Selector Switch (Detent Switch)

• Manually set switch, that stays on until turned off

Electrical Limit Switch

• Deployed when a cylinder fully extends or retracts.

Hydraulic Symbols

Pump Unit

• Consists of a motor, pump (to generate pressure), pressure relief valve, and pressure gauge.
• Fluid returns to the tank (indicated by the letter 'T').

Four Three Hand-Lever Valve Centre Shutoff

• Center position blocks any fluid flow
• Position is adjusted using a lever

Four Three Hand-Lever Valve With Bypass Position

• Has a middle position that connects flow from the pressure side to the tank.

Four Three Hand-Lever Valve With Floating Position

• Has a middle position that allows fluid flow between two different parts.

Test your knowledge of pneumatic, electro-pneumatic, and hydraulic symbols with this engaging quiz. Understand key components and their applications, as well as memorization of essential symbols. Perfect for engineering students and professionals alike.