CCT Pneumatic Principles & Air Flow Mechanics 2 — Questions and Answers
Question 1: What does CFM stand for in Casper pneumatic tube system blower specifications?
- Carrier Flow Management
- Central Fan Module
- Cubic Feet per Minute (Correct answer)
- Compressed Force Measurement
Correct answer: Cubic Feet per Minute
CFM (Cubic Feet per Minute) is the standard unit for volumetric airflow rate and is a key specification when selecting or replacing blowers in pneumatic tube systems.
Question 2: How does installation at high altitude affect Casper pneumatic tube system performance?
- Performance improves because air resistance is lower at altitude
- Altitude has no measurable effect on pneumatic system performance
- Reduced air density at altitude requires increased blower capacity to maintain performance (Correct answer)
- Higher altitude automatically increases carrier speed due to thinner air
Correct answer: Reduced air density at altitude requires increased blower capacity to maintain performance
At higher altitudes, lower air density reduces the pressure differential a given blower can generate, requiring larger or faster blowers to compensate.
Question 3: What is the function of an inlet air filter in a Casper pneumatic tube system?
- To increase the velocity of air entering the blower
- To remove dust, debris, and particles from the airstream before they reach the blower (Correct answer)
- To measure the volume of airflow entering the system
- To reverse airflow direction during bidirectional operation
Correct answer: To remove dust, debris, and particles from the airstream before they reach the blower
Inlet filters protect blowers and system components from contamination by trapping particulates in the airstream before they can cause mechanical wear or blockages.
Question 4: In pneumatic tube system airflow analysis, what does 'static pressure' represent?
- The pressure measured only when carriers are actively moving
- The resistance force that the blower must overcome to push air through the system (Correct answer)
- The speed of air measured at the center of the tube cross-section
- The weight of a stationary carrier resting in the tube
Correct answer: The resistance force that the blower must overcome to push air through the system
Static pressure is the resistance component of air pressure — it acts perpendicular to airflow and represents the system resistance the blower must overcome.
Question 5: In a bidirectional Casper pneumatic tube system, how is carrier direction reversed?
- A technician manually rotates the carrier 180 degrees at the sending station
- Reversing valves redirect blower airflow so it draws from the opposite end of the tube (Correct answer)
- Additional blowers at the destination push the carrier back toward the origin
- The tube diameter is increased at midpoint to change flow characteristics
Correct answer: Reversing valves redirect blower airflow so it draws from the opposite end of the tube
Reversing valves switch which end of the tube network the blower draws from, flipping the pressure gradient and driving carriers in the opposite direction.
Question 6: What is the most likely effect of a significant air leak in a Casper pneumatic tube system?
- Carrier speed increases because turbulence adds propulsive energy
- The pressure differential decreases, causing slower or incomplete carrier transport (Correct answer)
- Only the blower motor temperature is affected, not carrier movement
- The system self-compensates and performance is unaffected
Correct answer: The pressure differential decreases, causing slower or incomplete carrier transport
Air leaks allow pressure equalization, reducing the effective differential across carriers and resulting in insufficient driving force, slower speeds, or failed transfers.
Question 7: What is 'velocity pressure' (dynamic pressure) in the context of pneumatic tube airflow?
- The manufacturer's maximum rated operating pressure for the tube
- The additional pressure added by the carrier's own weight in the tube
- The pressure component associated with the kinetic energy of moving air (Correct answer)
- The minimum blower pressure required to start a carrier moving from rest
Correct answer: The pressure component associated with the kinetic energy of moving air
Velocity pressure (dynamic pressure) represents the kinetic energy of the moving airstream and equals total pressure minus static pressure in the system.
CCT Pneumatic Principles & Air Flow Mechanics 2
What does CFM stand for in Casper pneumatic tube system blower specifications?