BCIT: Millwright Level 3 (Pumps - Detailed 2)

(Flashcards and MC Questions)

How does a pneumatically activated double diaphragm pump achieve double-acting operation?

Alternating Air Pressure via Spool Valve and Dual Diaphragms

What is the major advantage of a pneumatically activated pump when the discharge line becomes blocked?

Pressure Is Limited to Air Inlet Pressure with no Mechanical Damage

What should be inspected on reciprocating pump plungers and rods during maintenance checks?

Scoring, Discoloration, Runout, and Corrosive or Erosive Wear

Why must control spool valves use filtered, regulated, and lubricated gas?

To Prevent Seizure and Ensure Reliable Operation

What is the main design difference between a two-screw pump and a three-screw pump?

Drive Arrangement and Use of Idler Screws

Why is a relief valve required on the discharge side of most positive displacement pumps?

To Prevent Overpressure and Equipment Failure

Why is a foot valve generally unnecessary for positive displacement pumps?

Self-Priming

What is the critical safety warning when charging a gas-charged pulsation dampener in oil systems?

Never Use Oxygen because it can cause Explosion with Oil

What is the formula for velocity head in fluid systems?

Hv = v² / (2g)

where:
- v is velocity (ft/s)
- g is 32.2 ft/s²

What is vapour binding in pumps and what causes it?

Vapor Formation on Suction Side that Blocks Flow

What is Net Positive Suction Head (NPSH) in a pump system?

Minimum Pressure Required to Prevent Cavitation

What is slip factor in positive displacement pumps?

Difference Between Theoretical and Actual Discharge