Pneumatic Principles & Air Flow Mechanics Flashcards

What is the primary cause of pressure loss in long Casper pneumatic tube runs?

Answer: Friction between the moving airstream and the interior tube wall surface

Friction between the moving air and the tube wall surface creates cumulative resistance (pressure loss) over long distances, requiring appropriately sized blowers.

According to the continuity principle, how does increasing tube diameter affect air velocity when blower output (CFM) is constant?

Answer: Velocity decreases because the same air volume fills a larger cross-sectional area

The continuity equation (A × V = constant) shows that increasing cross-sectional area while keeping airflow volume constant must reduce velocity.

In Casper pneumatic tube system airflow analysis, what does 'total pressure' equal?

Answer: Static pressure plus velocity (dynamic) pressure

Total pressure is the sum of static pressure (system resistance) and velocity pressure (kinetic energy of the moving air), representing the total energy of the airstream.

Which two parameters are most critical when selecting a replacement blower for a Casper pneumatic tube system?

Answer: Required airflow volume (CFM) and static pressure capacity (in. WC or in. Hg)

Correct blower replacement requires matching both the required volumetric airflow (CFM) and the system's static pressure demands to ensure reliable carrier transport.

What is the purpose of a check valve in a Casper pneumatic tube system?

Answer: To prevent reverse airflow and carrier backsliding when the blower shuts down

Check valves permit airflow in only one direction, preventing carriers from reversing or air from back-flowing when blowers cycle off between carrier transfers.

How does tube run length affect the blower pressure requirement in a Casper pneumatic tube installation?

Answer: Longer runs require higher blower pressure to overcome greater cumulative friction losses

Friction losses accumulate over every foot of tube run; longer systems demand higher blower pressure ratings to maintain sufficient carrier-driving force at the far end.

In a Casper pneumatic tube system, what role does the electronic control module play in managing airflow and carrier routing?

Answer: It sequences blower activation and diverter valve positions to route carriers to their correct destinations

The control module reads each carrier's destination address and coordinates blower timing with diverter valve switching to automatically route carriers through the correct tube path.