Plant Operator Selection System Mechanical Concepts Flashcards
7 cards from real Plant Operator Selection System Test practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Plant Operator Selection System Mechanical Concepts flashcards as text
A pump is operating at 1,800 RPM and moves 50 gallons per minute. If the speed is increased to 3,600 RPM, approximately how much fluid will the pump move per minute?
Answer: 100 gallons
Pump flow rate is directly proportional to shaft speed, so doubling RPM doubles the flow rate from 50 to 100 GPM.
Which type of valve is best suited for completely stopping or fully opening flow in a pipeline, but is NOT recommended for throttling?
Answer: Gate valve
Gate valves are designed for fully open or fully closed service and can be damaged if used to throttle flow.
A wrench with a 12-inch handle requires 30 lb of force to turn a bolt. What force would be needed if the handle were extended to 18 inches?
Answer: 20 lb
Torque must remain constant, so force × distance = 30 × 12 = 360 lb-in; 360 ÷ 18 = 20 lb.
In a hydraulic system, a small piston with an area of 2 sq in supports a large piston with an area of 20 sq in. If 10 lb is applied to the small piston, what load can the large piston support?
Answer: 100 lb
Pascal's law states pressure is equal throughout, so 10 lb ÷ 2 sq in = 5 psi × 20 sq in = 100 lb.
Which of the following best describes the purpose of a pressure relief valve in a piping system?
Answer: To prevent system pressure from exceeding a safe limit
A pressure relief valve automatically opens to vent excess pressure and protect equipment when system pressure exceeds a set point.
A belt drives two pulleys. The drive pulley has a diameter of 6 inches and spins at 900 RPM. What is the speed of the driven pulley if its diameter is 3 inches?
Answer: 1,800 RPM
Speed ratio is inversely proportional to diameter ratio: 900 × (6 ÷ 3) = 1,800 RPM.
When a fluid flows from a wider pipe section into a narrower pipe section at constant volumetric flow, what happens to the fluid velocity?
Answer: Velocity increases
By the continuity equation, the same volume must pass through a smaller area, so velocity must increase.
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