Peter Schüten is the Almatec product manager with Almatec Maschinenbau GmbH, Kamp-Lintfort, Germany. He may be reached at firstname.lastname@example.org or +49 2842 961-0. For more information, visit almatec.de and psgdover.com.
This equipment avoids the risk of leaks and pipe damage associated with injection mold pumps.
Image 3. Harsh chemicals can cause compatibility concerns when used with some types of pumps. One type of AODD pump can be constructed of plastic materials that are specifically compatible with the chemicals they will handle, which eliminates corrosion and leak concerns.
AODD pumps avoid these shortcomings. Specifically, plastic solid-body AODD pumps are the preferred choice in harsh chemical applications. In general, solid-body AODD pumps are stronger and have a longer life cycle with less required maintenance. Injection-molded plastic pumps, however, can have small cavities or crevices in the body where liquids can accumulate and potential leak paths can be created. During operation, injection-molded pumps can also bounce more, which can loosen pipework and increase the chances for a product leak.
Image 4. Other positive displacement pump styles, such as gear and lobe, lose volumetric consistency over time, leading to higher operating costs. AODD pumps reliably maintain their flow rates, resulting in optimized production cycles and energy usage.
Plastic AODD pumps can be constructed of materials that are specifically compatible with the chemicals they will handle, which eliminates corrosion and leak concerns. AODD pumps are dry-run capable, easy to control and sealless. Their compressible drive medium permits gentle delivery with attenuated pressure peaks. Startup is simple, and the space required is considerably less than that of piston-actuated diaphragm pumps or eccentric screw pumps.
Image 5. During their operation, injection-molded AODD pumps can bounce, which can loosen pipework and increase the chances of a chemical leak. Solid-body AODD pumps are more stable during their operation, which leads to a higher level of product containment.
One type of plastic body AODD pump offers features and benefits for handlers of dangerous chemicals.
- Solid-body construction. The pumps are computer numerical control (CNC)-machined from solid blocks of polyethylene (PE) or polytetrafluoroethylene (PTFE). The result is a pump that is not prone to the creation of leak paths and able to operate with the most dangerous chemicals in the harshest environments.
- Diaphragm and containment ring. The pumps feature a stainless-steel containment ring and ring-tightening structure that helps create consistent high-torque compression. This pulls the components tightly together and compresses the diaphragm in such a way that a leak-free seal is achieved.
- Air control system. The air control system is a lube-free valve with only two moving parts that allows the pump to achieve superior flow-rate efficiency and air consumption, which lowers the overall cost of operation.
- Material compatibility. The pump's housing can be constructed of PE, PTFE, PE conductive or PTFE conductive, which allows it to be used with a wide range of chemical formulations. Additional versatility in regard to material compatibility is realized through the availability of ethelyne propylene diene monomer (EPDM), PTFE/EPDM and nitrile rubber (NBR) diaphragms; EPDM, PTFE, NBR and stainless-steel ball valves; and PTFE cylinder valves.
- Intrinsic safety. Pumps that are constructed of PE/PTFE conductive plastics are intrinsically safe and meet the requirements of the Explosive Atmospheres (ATEX) 94/9/EG directive. This means they can be safely used in explosive atmospheres or when pumping flammable liquids.
While we may not want to know what types of dangerous chemicals, solvents, caustics or acids are used to make paints, detergents, paper and fertilizer, we know that we cannot live without them and that we do not want the dangerous materials to be released to the environment.
That is why full containment of these hazardous, flammable or explosive substances is a front-of-mind concern for the plant operators who handle them. Those concerns can be alleviated, however, through the use of pumping equipment that has been designed to achieve full containment of dangerous chemicals.