A quick guide to select the correct AODD pump for your specific application
When deciding which Double -operated air diaphragm pump (AODD) Selecting for a specific application, the first crucial question to ask is what material is being pumped? More specifically, what is the material's solid content, pH level, viscosity, density, and specific gravity, and is the material abrasive? All of these considerations have a major impact on the compatibility of the material with the bomba.
Aluminum, for example, offers only medium corrosion and abrasion resistance and is not suitable for halogenated hydrocarbons, while polypropylene has a much broader chemical compatibility. However, polypropylene has a limited temperature range, so for higher temperatures other materials need to be chosen. PVDF (Kynar) exhibits strong chemical resistance to acids and bases, good resistance to abrasion and resistance to high temperatures. PTFE displays the broadest chemical compatibility, extreme corrosion resistance, has a very low friction coefficient, not adhesive, provides high heat resistance, but offers low abrasion resistance. Another essential material for AODD pumps is Santoprene, which offers good resistance to abrasion and chemistry, and adequacy for use with some solvents, caustic solutions, diluted acids and alcohols.
The next consideration is the application. Which flow do you need, where is the power tank in relation to the pump and what is the total suction length, vertical elevation and discharge distance? All of this plays a role in determining the input and exit hose diameter.
If an Atex certification pump is required or does not have influence. If not, then a polypropylene or PVDF pump can be chosen. If ATEX certification is required, then a conductor polypropylene offers chemical resistivity at a low cost, while Hastellloy offers even greater resistance to chemicals, it is mechanically robust but expensive.
Let's now consider what type of pump Aodd select for specific applications.
Circulation and transfer of paint
A challenge with this application is that a very long hose length is often necessary, sometimes up to 250 meters, so it is important to get the right combination between fluid pressure and volume. The suspension of ink is another challenge. For example, zinc metal or epoxis paints need to remain in suspension, which discards a pressurized system. In addition, the ink is shear sensitive, so a pump needs to be selected to prevent shear. A typical grace solution for circulation and ink transfer is a Husky 716, 1050, 1590, 2150, 3300 or 1050e model. The wet section is metal, the PTFE (overmolded or 2 pieces) and Santoprene diaphragms, and the seats built of polypropylene, santoprene, PVDF or stainless steel.
Graphite transfer in pipe manufacturing
During the process of making a tube, graffiti needs to be transferred as a lubricant to the mandrel. Graphite powder is mixed with water. Challenges include high application temperature and viscous, thixotropic and abrasive material. A conventional piston pump is not for this application as it will separate graphite from water and obstruct the pump. The graco solution would be a Husky 2150 aluminum pump with a 2 -inch output tube, stainless steel spheres and a Santoprene diaphragm.
Pumping an injectable gel inside a wall
Such application is common in the construction industry, for example, to control moisture in a basement. Controlled manual distribution is required for highly viscous material. Low pumping and low pressure volume are used to inject the gel. If a material like siloxane is used, the pump should be corrosion resistant. Graco recommends its Husky 307 acetal pump, which has a corrosion acetal body along with internal PTFE parts. Acetal offers wide solvent resistance and supports extreme fatigue while providing a good level of abrasion resistance.
Chemical transfer in stack leaching
To extract minerals from the stone, the pile of crushed ore is sprinkled with an acid (eg sulfuric) that penetrates the ore and dissolves the minerals. The leaching solution then needs to be pumped into the mixing and separation process. Obviously, the main requirement is a bomb that resists strong acids and cyanide solutions. It should also provide high flow as large amounts of acids are used, while a leakless project is essential to avoid contamination of the environment. A good solution is a 2 -inch Husky Groke Pump with a stainless steel center and fluid section, and Santoporne's internal pieces. A polypropylene center and fluid section are also possible. For higher flow rates, a 3 inch pump would be preferable.
Metal coating
This application concerns the coating of small metal components with protective or decorative zinc coatings. AODD pumps are suitable for this application and are used for the transfer of chemical kitchen coating material to the immersion tanks and back to the kitchen, where the sludge is separated from the coating material and later processed by a filter press. The main requirements are chemical compatibility and a design without leakage. A graco husky 1050, 1590 or 2150 pump with a PVDF body and internal PTFE parts is suitable. When a sodium hydroxide bath is included, the pump should have a polypropylene body and internal components of Santoporne.
Ceramic
The challenge faced by bombs in the ceramic industry is the presence of highly abrasive and highly viscosity landslides and clocks that need to be transferred in large volumes. Generally, a 1 ”or 2” 1 ”or 2” aluminum pump is suitable. The wet section can be metal or plastic, with Santoporne's spheres, stainless steel seats and geolast or santoprene diaphragms. For larger castings, larger size pumps should be selected.
GRACO provides a lot of information and tools to help you decide which AODD pump to select for each specific application.
For example, the detailed guide to building materials Graco describes all materials commonly used in the manufacture of AODD pumps, along with their temperature range. It indicates whether each material is suitable for soft chemicals, aggressive chemicals, high temperatures and abrasive.
Graco also provides pump performance charts to help you determine what air consumption will be at a certain pressure and fluid flow as well as a Diaphragm pump selection tool.
