The goals of minimizing pump-seal wear and prolonging seal life can be aided by devising executing a flush plan. That’s the prescription according to a blog post from Crane Engineering application engineer Jorie Ballun.

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Circulating fluid to or from the seal chamber will maintain proper lubrication, pressure, temperature, and solids management. Image source: Crane EngineeringSuch a flush plan, Ballun says, features an equipment arrangement that circulates fluid to or from the seal chamber to maintain proper lubrication, pressure, temperature and solids management.

While some flush plans use the pump geometry to function, Ballun focuses on external flush plans—using tubing and fluid treatment devices to redirect fluid to or from the seal chamber. Pumping hazardous or dangerous fluids requires a more aggressive flush plan.

With a simpler plan, the suction or discharge pressure of the pump will move the fluid across the seal faces. Here, the piping will include orifices leading from a port to the seal chamber. Whether connecting to the discharge port to deliver high-pressure discharge fluid, or to the lower-pressure suction port, you’ll provide lubrication and cooling while flushing solids away from the seal.

Ballun says that in some cases, the process fluid must be treated before reentering the seal chamber. For example, heat exchangers or cyclone separators will cool the fluid or remove solids before it passes over the seal. And in more challenging cases, an external fluid source--cool plant water, for example--may be required, diluting the process product as seal water is introduced into the system.