Structural Pest Control Applicator Practice Exam

Which pump type does not possess an automatic pressure relief characteristic?

1. Roller pump

2. Centrifugal pump

3. Piston pump

4. Diaphragm pump

The correct answer is: Piston pump

The piston pump is known for its ability to create high pressures and deliver fluids at controlled rates, but it does not have an automatic pressure relief characteristic. This means that if the discharge line becomes blocked or if the back pressure increases beyond the pump's designed limit, the pump could potentially be damaged without a relief mechanism to reduce that pressure. In contrast, centrifugal pumps, diaphragm pumps, and roller pumps generally have features that allow them to handle pressure fluctuations automatically. For instance, centrifugal pumps often have designs that allow them to run dry without damage by enabling fluid movement to change based on pressure changes. Diaphragm pumps can flex with pressure changes and often include built-in relief mechanisms. Roller pumps can manage pressure variations due to their operational design, which allows them to handle changes without damage. Understanding the characteristics of these pump types is crucial for selecting the appropriate pump for specific applications in pest control, especially where pressure management is critical for the effective application of pesticides.