Air-operated double-diaphragm pumps in GA are usually used for transfer applications and can handle a wide variety of feeds. Although they are tough, reliable and easy to maintain, they can be noisy, prone to icing, and are limited to low-pressure applications.
What are the main features and benefits of air-operated double-diaphragm pumps in GA?
AODD pumps are essentially leak-free. There are only stationary seals between the wetted parts and the outside environment, so leakage can only occur if one or both diaphragms fail. As part of a general maintenance program, diaphragms should be replaced regularly, according to the manufacturer’s recommendations. Diaphragms suffer less wear in an AODD pump than those in a mechanically driven diaphragm pump because of the benefit of pressure balancing by the compressed air supply.
AODD pumps are capable of handling abrasive, highly viscous fluids, sludge or slurries. In addition, the gentle pumping action makes them ideal for shear-sensitive fluids. The four internal check valves generally use either a ball (or cone)/seat or flap design. Ball valves provide a better seal and are less prone to wear than flap designs. Since flap-type valves are hinged, long-term use eventually causes fatigue at the flexing point. Ball valves wear more evenly since the ball is free to rotate during operation and settle in a different position on the seat. Flap-type check valves have the advantage that they can more easily pass large solids within the pumped fluid.
With no internal seals or moving components requiring lubrication and cooling, an AODD pump can be run dry indefinitely without damage. Air-operated double-diaphragm pumps in GA are self-priming and some are capable of a suction lift of up to 8m.
AODD pumps are suitable for use in hazardous areas because of the use of compressed air as the power source rather than electricity. For the same reason, an AODD pump can be safely submerged – as long as the air vent is above the liquid level.
What are the limitations of air-operated double-diaphragm pumps in GA?
1. The efficiency and stability of an AODD pump are dependent on its compressed air supply, which tends to limit the use of AODD pumps to low-pressure applications.
2. The air distribution system provides the power and control for an AODD pump. The hardware is relatively cheap, simple and easy to maintain. However, in some plant environments, it may be necessary to filter expelled air to capture contaminants such as oil.
3. Icing can be a problem with poorly designed air distribution systems. The constant venting of air causes cooling and, in extreme cases, this can result in the build-up of ice around the air vent or within the distribution system.
4. The cyclic action of a diaphragm creates pulses in the discharge with the fluid accelerating during the compression phase and slowing during the suction phase. Pulsing can cause damaging vibrations in the discharge system and a flexible connection at the pump outlet reduces the likelihood of loosened connections and leakage.
5. AODD pumps can also be noisy, not only because of vibrations resulting from the pulsing action but also because of the constant venting of the air valves.
Air-operated double-diaphragm pumps in GA pumps are robust, reliable, easy to maintain, and relatively low cost. They tend to be general workhorse devices and are typically used for transfer applications in a wide variety of industries. We specialize in a variety of advisory and installation services, all designed to help you get the most out of your liquid handling equipment. And we’re certified to maintain and repair all the equipment we supply to our clients, so call us today!