Mechanical seals are designed to produce an acceptably low level of leakage to function effectively. Many individual internal and external factors, as well as interactions between them, affect the rate of seal leakage.
When the City of Delaware, Ohio, expanded its wastewater treatment plant, it looked to increase more than just capacity. It also wanted to increase its efficiency and automation capabilities to benefit the plant's operators and taxpayers.
Last month, we looked at adjustable frequency AC drive system, induction motor speed control and motor application and performance. This month we will explore specific operation conditions, applications and performance.
If a centrifugal pump is started with the discharge valve open too far and with a low discharge pressure, the liquid in the suction line may accelerate at a rate that causes the suction pressure to drop below vapor pressure.
When it comes to pressure and flow, variable speed pumping applications can be divided into three basic categories. Constant pressure-variable flow (Cp-Vf) attempts to keep pressure relatively constant over a range of flows. Constant flow-variable pressure (Cf-Vp) tries to achieve the opposite by using varying pressure to keep flow constant. Variable pressure-variable flow (Vp-Vf) applications can accommodate a change in both.