What happens if a positive displacement pump operates with closed valves?

When a positive displacement pump operates with closed valves, it can lead to excessive pressure build-up within the pump and associated piping. This type of pump works by trapping a fixed amount of fluid and then displacing that volume through the discharge outlet. If the discharge is closed off, the pump continues to operate and attempt to move fluid, but with nowhere for the fluid to go, pressure increases significantly.

This pressure build-up can exceed the pump's design limits and potentially cause damage to the pump itself, such as rupturing the pump casing or damaging seals. It also poses a risk of damaging the entire piping system, so it's crucial to monitor and manage the operation of positive displacement pumps carefully to prevent this scenario.

In contrast, if valves are left closed, the efficiency of the pump is compromised as it is not able to perform its intended function of moving fluid effectively, and cavitation is not prevented since it is not just a matter of pressure but flow dynamics at stake, which become disrupted when there is no outlet. This understanding is vital for anyone working with water treatment systems to avoid catastrophic failures and ensure safe operations.