An important construction element in Almatec air-operated diaphragm pumps is the solid body design. Only a solid plastic body can support the necessary weight for an oscillating pump. The individual components can be designed, so that the required wall thicknesses are arranged where they are needed. The mechanical machining of a solid plastic block is economical thanks modern CNC technology, enabling tight tolerances to be achieved. The high static mass leads to smooth operation and eliminates the need for unnecessary external metal parts that otherwise be used for reinforcement. In all Almatec pumps, only virgin PE and PTFE, produced in Germany, are used.

Polyethylene (PE)

PE is very tough and exceptionally resistant to wear, has low water absorption capacity and displays good general resistance to chemicals. Only such strong oxidants as nitric acid, oleum and halogens can damage PE.

PE (polyethylene) competes with PP (polypropylene), which is frequently used in the manufacture of pumps. Thermally and chemically speaking, there are virtually no differences between the two. However, the similarity ends where the mechanical properties are concerned. Trials based on the sand-slurry method have shown that the abrasion resistance of the PE (material sample on top) is 7 times higher than that of PP (middle) and even 1.6 times higher than that of steel (bottom). It is certainly also more wear-resistant than, for example, cast iron or aluminium. This high resistance to abrasion plays a vital role in many applications (e.g. slurry delivery in the wafer manufacturing in the photovoltaic industry, pickling baths in the electroplating industry, printing inks, lime slurry for wet desulphurization, ceramic mass and glazes in the ceramics industry). For explosion-proof areas (ATEX conformity) and for flammable liquids, PE conductive as housing material is available.

Almatec pumps with PE housing: E-SERIES, FUTUR, AH, CX

Polytetrafluorethylen (PTFE)

PTFE has a smooth surface, very low friction coefficient, is physiologically safe, can be used over a wide range of temperatures and displays virtually universal resistance to chemicals. However, pure PTFE has very little resistance to abrasion and tends to cold-flow. For explosion-proof areas (ATEX conformity) and for flammable liquids, PTFE conductive as housing material is available.

Almatec pumps with PTFE housing: E-SERIES, FUTUR

Stainless Steel

Stainless steel 1.4408/SS316 (G-X 6 CrNiMo 18 10) is a cast steel that is resistant to corrosion and acids and is frequently used for fittings and pump casings because of its good general chemical stability. In a precision lost-wax casting operation, stainless steel is used for the wetted housing parts in Almatec pumps. The lost-wax process is a complex casting process yielding a smooth and dense surface with increased resistance to corrosion. The housing parts are additionally glass-bead blasted and pickled. The polished version is subjected to three additional machining stages, namely grinding, mechanical and electrolytic polishing.

Another used stainless steel pump housing material is 1.4435/SS316L (Basel Standard II, ferrite content < 1%). It has a surface roughness of ≤ 0.4 μm.

Almatec pumps with 1.4408 housing: CHEMICOR, AH-S
Almatec pumps with 1.4435 housing: BIOCOR