AODD pumps rise to the challenge

12 March, 2008

Air operated double diaphragm (AODD) pumps are seen by most users as rugged and durable, which work in all conditions. The AODD pump is suitable for many applications in most industries, including the following: paints and oils, solvents; paper printing ink; finishing/surface treatment, galvanized wash, acids; chemicals; cosmetics lotions, shampoo, liquid soap, deodorants; pharmaceuticals syrup, alcohol, glycerine, sweeteners; manufacturing oil, coolants, degreasing wash, emulsions, waste oil; water purification polymers; construction and general industry; aviation emptying/filling fuel; petrochemical tank cleaning; and marine waste water/bilge pumping.

The basic design has remained almost unchanged since the pump’s introduction, confirming the strength of its working principle. However, the demand to increase productivity has highlighted the drawbacks of the AODD pump. Running costs are high compared to other pumps, especially electrical drive pumps, due to energy usage. On the other hand, there are several benefits of air driven pumps, such as ease of use and ability to operate in explosive environments. As energy prices increase, energy consumption will become more and more important to the user, which means the challenge is on to create a more efficient AODD pump solution.

If you look at the running costs of an AODD pump the four largest areas are:
- down time due to failure or service
- energy costs
- installation & repair
- spare parts

Albin Pump has focused on these issues in the development of its AD pump. By addressing these issues, the aim is to provide industry with a pump that allows users to increase productivity while also reducing the running cost of their pump solutions.

The company has been able to meet the challenge by changing the basic design of the AODD pump. The result is a pump that will add value to applications in terms of cost reduction by using less energy and a reduction in downtime.

Let’s first take the area of cost reduction by using less energy. This is achieved through a reduction of friction and current losses, which means less energy is consumed, lowering costs. The reduced friction and current losses also reduce pulsation. AODD pump users can now reduce their compressed air consumption by 30 to 45 per cent and drive down their pump operating costs.

In order to reduce downtime, the Albin AD pumps are designed with a minimum of moving parts and all parts are changeable with the pump left in the piping system (see pic 1). The lifetime of the diaphragms are increased up to five times due to the diaphragm suspension.

These two design improvements are illustrated in pic 2 (the frictionless pivoting valves) and pic 3 (the flexible diaphragm suspension). These two design features, in conjunction with the central flow path and the feathered flap valves create important improvements compared to traditional AODD pumps.

The features and benefits of these construction solutions is demonstrated by a user of AD pumps. The customer is using the pump in ink handling systems for flexo printing presses. It is important to the customer that the pump has low pulsation and it requires minimum maintenance. The reduction in pulsation in this application contributes to better performance and also achieves a three to fivefold increase in diaphragm life by reducing the forces that are acting on the diaphragms – less pulsing simply means less wear.

The possibility for the pump to operate in any orientation – total inverted operating capability (see pic. 4) – also means costs can be reduced as less piping is required and mounting the pump is easier.

This is also illustrated in an application at French company Gerflor. As you can see from picture 5 the pump can be installed as an integrated part of the piping system without the need for expensive mounting solutions and pulsation dampers. This is made possible by the low pulsation and therefore low vibrations and sound levels. The loads in the system are reduced, increasing the number of potential application areas.

Enhanced pumping performance, near silent operation and ATEX compliance provides a pump system that can meet demanding operating requirements.