The technology of wastewater treatment plants guarantees supplies of fresh, clean water. While usually thought of as a “dirty business,” such systems are essential to our health and the environment. Did you know that wastewater treatment plants utilize components manufactured on DESMA machines?

Because of the high solids content in wastewater sludge, progressive cavity pumps (PC pumps) are frequently used to transfer the material from one location to another. A vital component of any progressive cavity pump is the pump stator.

PC pump stators consist of an outer tube (casing), usually made of metal, and a rubber lining in a unique design. The unique design of the rubber lining is formed by a part of the mold known as a core which is removed after the injection process. DESMA elastomer injection machines and molds are commonly used to manufacture these specialized articles. In the DESMA machine, the uncured rubber compound is plasticized, then injected between the casing and the core while in a hold mold. After injection, the material is cured in the mold until it is ready for removal, after which time the core can be removed from the molded articles.

In some specialized applications, very large stators are required (over 10’ long). Special DESMA machines explicitly designed for the application, like the 969.318 Z2, are used in these cases. This machine has two (2) DESMA injection units that operate in series. Depending on the size of the stator that requires filling, the two injection units alternate until the required volume is reached. Thanks to the multi-inject function, injection volumes of several hundred liters can be achieved by injecting the rubber compound directly into the stator pipe. Since these articles are so large, they must be cured in an autoclave instead of a mold after injection. Then, after vulcanization, the core is removed, resulting in the final article.

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