Step 1: Understanding the Concept:
Evaporators can have liquid droplets in the vapour stream.
A device is used to prevent this.
Step 2: Key Formula or Approach:
No specific formula.
Need to know the components of an evaporator.
Step 3: Detailed Explanation:
An entrainment separator is used to prevent liquid droplets in the vapour stream.
It removes droplets before they leave the evaporator.
Vacuum systems maintain pressure.
Calendria is the heating section.
Vapour compressors are for vapour recompression.
Thus, the entrainment separator is the correct device.
Step 4: Final Answer:
An entrainment separator prevents liquid droplets in the vapour stream.
Hence, the correct option is (C).