For parallel operation of two or more pumps, how is the combined performance curve obtained?

The process of obtaining the combined performance curve for parallel operation of two or more pumps involves adding the capacities horizontally at the same heads. This means that for a given head, you sum the flow rates of each pump operating at that specific head.

In parallel configurations, the pumps are designed to share the workload, allowing the total capacity (flow rate) to increase while maintaining the same discharge pressure (head). This is effectively because each pump contributes its flow rate to the total system flow, leading to a higher capacity at a consistent head. Therefore, the performance curve will reflect this increase in flow capacity at the same point of head, resulting in a curve that exhibits higher capacities across the same head values.

This method is crucial for designing systems that depend on the combined output of multiple pumps, ensuring optimal performance and efficiency in the plumbing system. Overall, understanding how to construct the combined performance curve is key for predicting how two or more pumps will work together in a real-world application.