How to Minimize Friction Losses with AODD Pumps

Contributed by: Curtis Dietzsch at Wilden Pump


The goal of any pumping system is to be as efficient as possible. This allows end users to reduce energy costs, maintenance downtime, and increase productivity. An efficient pumping system is designed to transfer fluid (which can range water to concrete) by means of the most direct and unobstructed path possible. Unfortunately, there are barriers to this perfect model.

The Efficiency Challenge
Recognizing factors that cause energy loss

When pumping fluid, some degree of friction loss and inefficiency is inevitable. Friction loss essentially refers to resistance caused by fluid flowing through pumps, pipes, and fitting. That resistance results in decreased pumping pressure and decreased fluid velocity. Energy loss due to friction is dependent on a variety of factors, including the following:

  • Friction between fluid and piping walls – rough interior surface leads to higher losses

  • Friction between the adjacent fluids – higher viscosity fluids have higher losses

  • Turbulence created when redirecting fluid via a sharp turn in the pipe or a restriction – such as a valve, fitting, or reducer

  • Flow rate – high flow rates translate to high losses

  • Pipe length – longer pipes and small diameter pipes have higher losses

By identifying factors that cause friction loss in a pumping system, engineers and pump operators can reduce system flaws to create the most efficient system possible.

Solutions for Friction Loss
Factors to consider in pipe system efficiency

There are essentially four ways to increase efficiency in a piping system. Each solution addresses one of the factors that impacts friction loss.

  1. Reduce interior surface roughness of the piping system

  2. Increase pipe diameter of the piping system

  3. Minimize length of piping system

  4. Minimize the number of elbows, tees, valves, fittings, and other obstructions in the piping system; replace 90 degree turns with gentle bends.

The most efficient systems – ones that make the best use of a pump’s “pressure energy” – are those that have been designed with the least amount of impediments to maintaining the optimum flow. That means a piping configuration with the shortest possible piping runs, few or gentle pipe bends, minimal obstructions and larger pipe diameters. The most efficient systems will also utilize pumps that work seamlessly with the piping to maximize operational capability of the system by reducing friction loss and pump downtime.

Pump Type Matters
AODD pumps ideal for a variety of fluids

The pump type being used for a specific application also has an effect on pumping efficiency. Positive displacement pumps that use air-operated double-diaphragm (AODD) pump technology are proven to be the most effective and versatile pump type for a wide range of fluids, regardless of viscosity.

Diaphragm pumps are designed to move fluid through a piping system by developing a certain amount of head pressure. If a piping system is restrictive in some way, that pressure or energy is diverted towards overcoming the restrictions rather than towards its primary purpose, which is to move fluid. This results in wasted energy as a pump requires more energy to move fluid the same distance.

In some cases, pipe systems restrictions can cause the pump to ‘dead-head’, meaning the restrictions are so severe that the pump no longer has enough pressure/energy to move the fluid. Unlike other positive displacement pumps, AODD pumps can handle potential dead-heading without damage.

AODD pump technology has advanced to address concerns of friction loss and pump inefficiency. Several modern models now feature larger flow/wetted path that reduces internal friction and maximizes output and efficiency, a bolted configuration that ensures total product containment, and a variety of elastomers that meet abrasion, temperature and chemical-compatibility requirements

Read the original article on the PSG Dover website.

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