If a pump and force main are designed to deliver 300 gpm, what will happen if a duplicate pump is added to the system?

If a pump and force main are designed to deliver 300 gpm, what will happen if a duplicate pump is added to the system?

• A. You will pump 600 gpm.
• B. You will pump about 450 gpm.
• C. The amount of flow will depend on the static head loss.
• D. The amount of flow will depend on the static and dynamic head loss.

Answer: (D)

When a duplicate pump is added to a system designed to deliver 300 gpm, the flow rate is not simply doubled to 600 gpm because several factors affect the total flow. One of the primary considerations is the static head, which is the pressure required to lift the wastewater from a lower elevation to a higher elevation, as well as the dynamic head, which accounts for the friction losses and other resistances that occur as the fluid travels through the pipes. Adding a second pump theoretically could increase the capacity of the system, but the actual flow will depend on the combined effects of the static and dynamic head losses. If the system’s design and configuration allow the pumps to operate effectively together, the increased flow can approach the total capacity, but the static and dynamic conditions at which the system is operating will dictate the actual output. Therefore, the flow rate is contingent on these head losses, rather than simply being a mathematical sum of the pump capacities.

When a duplicate pump is added to a system designed to deliver 300 gpm, the flow rate is not simply doubled to 600 gpm because several factors affect the total flow. One of the primary considerations is the static head, which is the pressure required to lift the wastewater from a lower elevation to a higher elevation, as well as the dynamic head, which accounts for the friction losses and other resistances that occur as the fluid travels through the pipes.

Adding a second pump theoretically could increase the capacity of the system, but the actual flow will depend on the combined effects of the static and dynamic head losses. If the system’s design and configuration allow the pumps to operate effectively together, the increased flow can approach the total capacity, but the static and dynamic conditions at which the system is operating will dictate the actual output. Therefore, the flow rate is contingent on these head losses, rather than simply being a mathematical sum of the pump capacities.