Materials Handling
Seal-less gear pumps
In many chemical applications, the use of magnetic driven pumps can reduce lifecycle costs and minimise the risk of leakage. Dan Roldgaard reports.
W Fig. 1. Rotan
model MD33EFDK- 1U33 jacketed pump including carbon graphite bushings and high temperature magnets.
hen transporting toxic and environmentally hazardous liquids, the use of magnetically coupled pumps can be a very good alternative to traditional mechanical seal construction, as only minimal maintenance
is necessary. Since the mid-1990s, the Desmi Rotan type ED pump
(Environmental Duty) has become increasingly popular within a wide range of sectors. Major application areas include chemical raw and refined material transfer, liquid tar, pitch for making electrodes to the aluminium industry, liquid sulphur among many others. Rotan pumps are available in many different materials with or without heating jackets. Rotan magnetically driven pumps have two design features
which gives maximum performance during liquid transfer: The patented cooling system, which is an internal pumping system, eliminates the need for external cooling, and the dynamic axial balancing system which minimises axial loads, energy use, and ultimately increases lifespan. ED pumps are used in many
industries to pump a great variety of chemical raw material and finished products. Just two examples, which have often caused problems with sealed or packed pumps:
n Isocyanate (Toluene di-isocyanate and MD), prevents serious implications for health, safety and environment. At the same time life cycle costs are significantly reduced compared with traditionally sealed pumps.
Rotan’s magnetically coupled pump is the ultimate solution to one of the most hazardous problems of all pumps, namely the leakage problem. The Rotan ED pump offers a leakage free option and environmentally friendly transfer of liquids with viscosities up to 10000cSt. Isocyanate is one of the components in almost all foam products. There are various types of isocyanate, but common to all of them is that they react to the humidity of the air, thus forming very hard crystals which wear out the pumps and mechanical shaft seals. There are different methods to avoid this problem of humid air getting into storage tanks:
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