- Liquid Pulsation: Pulsation during liquid transfer occurs when there is a notable difference between the pump’s inlet pressure and head pressure. For example, it is not uncommon for both metal and plastic AODD pumps that have air-inlet pressure of 100 psi and head pressure of 90 psi to experience pressure swings of between 30 and 45 psi during every pump stroke. These conditions can result in sluggish flow rates and decreased operational efficiency.
- Water or Pipe Hammer: This phenomenon occurs when the pressure leaves the inlet pipe and moves downstream, and should this pressure hit a shutoff valve, it will rebound back within the piping at eight times the pressure than when it left. If this condition is left unchecked, the consequences can be severe, up to and including the forcing of valve balls through the valve seat, which will halt the pump’s operation.
- Piping Noise: A pulsating or turbulent fluid stream will create noise, or “chatter,” as the liquid moves around the valve balls, which, again will harm flow rates and efficiency.
The solution to these challenging pump conditions is the Wilden® Equalizer® Series Integral Surge Dampener (ISD). Available in plastic and metal models, the Equalizer ISD has been designed to integrate directly into the top of the pump’s manifold, removing the pressure variations and fluctuations that can result as the pumped liquid moves through the inlet toward the discharge.
The Equalizer ISD accomplishes this by creating a supplementary pumping action. By using a diaphragm as a separation membrane within the Equalizer, the Equalizer is able to trap a given volume of liquid on one side and pressurized air on the other. When the fluid pressure falls in the system, the Equalizer supplies additional pressure to the discharge line between pump strokes by displacing fluid via diaphragm movement. This movement provides the supplementary pumping action needed to virtually eliminate pressure variation and pulsation. In addition, operating off an air line that connects directly into an air regulator from the pump’s air line allows the Equalizer to run off the same pressure as the pump.
The resulting benefits are minimized pipe strain, reduced water/pipe hammer, lower levels of pipe noise or chatter, enhanced protection of inline equipment and lowered maintenance costs. The Equalizer ISD is available in three sizes – 13 mm (1/2″), 25 mm (1″) and 51 (2″) – and is available in a wide variety of materials – cast iron, 316 stainless steel, aluminum, polypropylene, PVDF, carbon-filled acetal, PFA and polyethylene, which enables it to be used in a wide range of temperature and chemical-compatibility conditions.
