Switching from volume to pressure in a multistage centrifugal fire pump can result in what effect?

Switching from volume to pressure in a multistage centrifugal fire pump typically results in an immediate doubling of the previous discharge pressure. This phenomenon occurs because centrifugal pumps operate on the principle of imparting kinetic energy to the water, converting it to pressure as water moves through the pump stages.

When the pump operates in a volume mode, it is designed to maximize flow at a lower pressure. However, when the pump is switched to pressure mode, it prioritizes maintaining or increasing discharge pressure, which can cause the pump to effectively leverage its design more efficiently, especially when additional stages are engaged. For instance, engaging another stage can immediately translate to significantly higher discharge pressure, potentially doubling it if the system is calibrated properly and meets the hydraulic requirements.

This transition might not drastically affect flow in the same manner; rather, it adjusts the relationship between flow and pressure. The flow rate does not simply decrease but depends on the system's resistance and the pump's ability to overcome it; this is not as straightforward as an immediate reduction. Therefore, the concept that the pressure can double instantly under certain operational modes emphasizes the dynamic nature of centrifugal pumps in various applications, especially in firefighting scenarios where high pressure and adequate flow must be balanced.