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Blacoh announces new dampener design for AODD pumps

Blacoh Fluid Control, part of the Blacoh Industries family of companies, has launched the AODDampener specifically designed for air operated double diaphragm (AODD) pump applications.

Blacoh's newly designed AODDampener is constructed of 316L stainless steel with a PTFE diaphragm, employs an automatic air control that utilises the existing compressed air source in an AODD pump system for charging.

This single configuration makes the dampener compatible with over 80% of the existing AODD pump applications in the US, Blacoh says.

Like other positive displacement pumps, AODD pumps can create damaging pulsations and vibrations due to the interrupted flow coming from the alternate filling and discharging of the two pump chambers.

Pulsation dampeners are commonly used to eliminate these pulsations by absorbing the energy from the pulse created on each stroke of the pump.

The dampeners are pressurised vessels with a flexible membrane inside that separates the gas charge from the system fluid and work according to the ideal gas law with Isentropic compression.

When the dampener is installed at the pump's discharge, as the pump discharges fluid it attempts to accelerate all the fluid in the line, increasing the line pressure.

As the line pressure increases, the dampener's internal membrane flexes and compresses the gas charge behind it allowing fluid to enter the dampener.

When the pump shifts and the flow from its discharge stops momentarily, the line pressure drops and the gas charge in the dampener then pushes fluid out of the dampener into the line, resulting in a relatively steady, smooth flow downstream of the dampener

If the average line pressure changes, the charge in the dampener needs to be adjusted to keep the dampener performing correctly.

The new AODDampener's unique automatic air control works with AODD systems where fluid pressures vary substantially on a regular basis.

"With the automatic air control, you don't have to adjust the dampener's charge at pump startup or when there is a change in system pressure. Just turn on the pump and the dampener adjusts itself," said Blacoh engineer David McComb.

The dampener's automatic air control system also makes it require no air unless the average line pressure in the system changes.

As the fluid line pressure increases, the air charge in the dampener is increased to match it, and when the line pressure drops, the dampener bleeds off charge, keeping the dampener optimally charged for maximum dampening effect.