If two centrifugal pumps, driven by two independent electric motors, operating at unequal speeds are discharging an inflammable liquid through a common discharge line, the higher speed pump may cause the slower pump to do which of the following?
• Centrifugal pump characteristics when pumps are in parallel on a common discharge header • Effect of higher discharge pressure from one pump on the other pump’s impeller and rotation • What happens to a centrifugal pump when flow is forced backward through it
• Think about what the faster pump is doing to the pressure in the common discharge line compared to the slower pump. • If the discharge pressure from one pump is greater than the head developed by the other, what will the direction of flow be through the slower pump? • How would reversed or forced flow through a centrifugal pump affect the impeller motion and the motor of the slower pump?
• Compare the discharge head of each pump: which one is higher and what that implies for flow direction. • Recall whether a centrifugal pump can act like a turbine if liquid is driven through it from the discharge side. • Ask: under these conditions, would the slower pump’s impeller tend to speed up, stop, or reverse due to the higher external pressure and backflow?
No comments yet
Be the first to share your thoughts!