CPE Mechanical Systems & Equipment 4

Question 1

In a shell-and-tube heat exchanger, baffles are installed to:

Accepted Answer

Direct shell-side flow across tubes and increase turbulence

Answer

Baffles force the shell-side fluid to flow perpendicular to the tubes, increasing turbulence and heat transfer coefficient while also supporting the tube bundle.

Question 2

A plant engineer observes that a reciprocating compressor is running hot. Which cause should be investigated FIRST?

Accepted Answer

Fouled or leaking valves reducing volumetric efficiency

Answer

Leaking or fouled compressor valves cause gas recirculation and recompression, which generates excessive heat and reduces capacity.

Question 3

The purpose of a pressure-compensated variable displacement pump in a hydraulic system is to:

Accepted Answer

Maintain constant pressure by varying flow output

Answer

A pressure-compensated pump automatically reduces displacement to maintain a set pressure, delivering only the flow needed to sustain that pressure.

Question 4

Which lubrication regime is characterized by full separation of mating surfaces by a fluid film?

Accepted Answer

Hydrodynamic (full-film) lubrication

Answer

Hydrodynamic lubrication occurs when a pressurized oil film completely separates the surfaces, preventing metal-to-metal contact.

Question 5

A plant uses a chain drive instead of a belt drive for a conveyor. What is the main advantage?

Accepted Answer

No slippage and positive mechanical drive

Answer

Chain drives engage sprocket teeth positively with no slippage, maintaining an exact speed ratio and enabling higher torque transmission.

(CPE) Certified Plant Engineer Practice Test

(CPE) Certified Plant Engineer Practice Test

CPE Mechanical Systems & Equipment 4