Refrigeration Plant Operator B Practice Test

Which method is NOT used to reduce liquid carryover with flooded shell and tube evaporators?

1. Mist eliminators

2. Surge drums

3. Centrifugal pumps

4. Extra cooling coils

The correct answer is: Centrifugal pumps

In the context of flooded shell and tube evaporators, liquid carryover refers to the unintended transportation of liquid refrigerant from the evaporator to the compressor, which can negatively impact the system's performance. To address this concern, several methods are commonly employed. Centrifugal pumps are primarily used to circulate refrigerants and are not designed to prevent liquid carryover. Their primary function involves moving fluids within the refrigeration cycle but does not directly address the issue of ensuring only vapor reaches the compressor. In contrast, methods that effectively reduce liquid carryover include mist eliminators, which capture small liquid droplets from the vapor stream; surge drums, which allow for the separation of liquid from vapor by providing a holding area where liquid can settle before recombination; and extra cooling coils, which can potentially enhance heat exchange and promote more complete vaporization of the refrigerant. By focusing on the role of each method, it becomes clear why centrifugal pumps do not contribute to the reduction of liquid carryover in this context.