Pneumatics Systems - MOY

Which type of device could give a pressure reading of -0.2 bars? (Negative pressure)

• Flowmeter

• Start-up valve

• Pressure gauge

• Vacuum gauge

Answer explanation

A vacuum gauge is designed to measure negative pressure, such as -0.2 bars, indicating a vacuum. Other pressure gauges measure positive pressure, making vacuum gauges the correct choice.

Pneumatic actuators are used to convert:

• linear motion into rotational motion.

• the energy stored in a pressurized fluid into electricity.

• rotational motion into linear motion.

• the energy stored in a pressurized fluid into motion.

Answer explanation

Pneumatic actuators convert the energy stored in pressurized air into motion, enabling various mechanical movements. Because air is a fluid, this makes the correct choice 'the energy stored in a pressurized fluid into motion.'

A safety relief valve is used to

• prevent air from flowing in a reverse direction.

• avoid excessive pressure build-up

• control the pressure regulator.

• drain dirty water from an air receiver.

Answer explanation

A safety relief valve is designed to avoid excessive pressure build-up in a system, ensuring safe operation by releasing pressure when it exceeds a predetermined limit.

Compressors usually pump air into

• pneumatic motors.

• pneumatic cylinders

• receivers

• atmosphere.

Answer explanation

Compressors are designed to pump air into receivers, which store the compressed air for later use. This is essential for maintaining pressure in pneumatic systems. Actuators like cylinders and motors use the air to create movement.

Which of these symbols represents a vacuum generator?

• A
• B
• C
• D

Which of the symbols represents a flowmeter?

• A
• B
• C
• D

Which of these pneumatic devices converts the energy of a pressurized fluid into motion? 

• Motors

• Actuators

• Cylinders

• All of the above

• None of the above

Answer explanation

Actuators, which include both cylinders and motors, convert the energy of a pressurized fluid into motion, making 'All of the above' the correct answer.

What could be the purpose of an accumulator in a pneumatic system?

• Mitigate the effects of long tubing

• Replace a portion of the tubing.

• Create a vacuum

• Reduce the number of manifolds required.

Answer explanation

An accumulator helps mitigate the effects of long tubing by storing compressed air, which can smooth out pressure fluctuations and improve system responsiveness.

Which of these part lists could be used to build a basic cheese press?

• Air bearing, pushbutton, tubing, air supply

• Pneumatic motor, pushbutton, accumulator, tubing, safety valve

• Pushbutton, cylinder, tubing, air supply

• Tubing, air supply, pushbutton, vacuum generator, suction gripper

Answer explanation

As you can see, the main element of the cheese press is a cylinder that applies the pressure on the cheese. Because 'Pushbutton, cylinder, tubing, air supply' is the only answer that includes a cylinder, it makes sense it is the correct answer. To work correctly, the press also needs a tubbung, air supply, and some way to turn it on and off, like a pushbutton.

With the following circuit, an operator reads a flow rate A on the flowmeter. Select the relation that best describes the flow rate B indicated on the flowmeter if the operator extends the tubing length to 0.6 m (keeping the diameter the same).

• A < B

• A = B

• B = 0

• A> B

Answer explanation

As the tubing length increases to 0.6 m, the flow resistance also increases, leading to a decrease in flow rate B compared to flow rate A. Therefore, B > A, which is the same as A > B is the correct relation.