July 2015

Magnetically Powered Pumps Seal the Deal

For companies pumping dangerous or expensive chemicals, leaks can endanger both personnel and the bottom line. Hermetically sealed, magnetically powered pumps are the state-of-the-play answer.

The list of potentially dangerous or simply-too-expensive-to-lose substances being pumped from one part of an industrial process to another somewhere in the world is long. Take isocyanates, for example. They’re the raw materials that make up all polyurethane products. Despite their relatively low acute toxicities, isocyanates can present harmful effects to the eyes, skin and respiratory tract (methyl isocyanate, for example, was at the centre of the 1984 Bhopal disaster).

Of course, few manufacturing or processing plants pump such substances on a truly large scale. But even the smallest of plants need to be sure they aren’t exposing their workers or surroundings to danger when working with solvents, printing ink, resin, pitch or hazardous organic liquids. And they need to guard their business economics against leaking non-hazardous, but pricey raw materials such as linseed oil, corn syrup or soyabean oil.

In such situations, the best and safest type of pump to use is a hermetically sealed, magnetically powered device based on the ROTAN® principle.


Patented no-leak principle
The basic concept of a ROTAN® pump differs from those of conventional pumps in that everything is completely and entirely sealed inside. Dirt or other contaminants have no way of entering the pump, and nothing within the pump can leak out.

The secret to achieving a fully enclosed design lies in the fact that, in contrast to conventional pumping systems, no holes or channels are required to bring electrical power into the pump. Instead, the medium being pumped circulates around a magnetic coupling carrying exactly the right number of magnets required for power to be transmitted from outside the device. Simple ‘centrifugal pump’-shaped channels in the shaft and rotor ensure continual replacement of the liquid heated by friction and re-circulation in the coupling. At the same time, this ensures efficient lubrication as well as heat transfer from the slide bearings. The pump can be easily reversed, too, causing its medium to flow in the opposite direction simply by reversing the motor’s direction. Finally, unlike centrifugal pumps, a ROTAN® pump offers gentle liquid-handling and a high priming vacuum, along with the ability to pump highly viscous liquids.


The unique, patented ROTAN® principle is generally recognized as the most advanced internal gear pump design available anywhere today. And it’s far and away the best solution for safely moving hazardous or costly substances. As an added bonus, there’s very little residue build-up, so far less cleaning is required.


Safety in product and supplier
While many pump manufacturers aspire to offering ROTAN®-style technology, DESMI A/S currently rules the market with its ROTAN® ED pump. The Denmark-based company has produced these pumps as part of its extensive product portfolio for over 20 years, building an impressive technological lead.

By now, we’ve worked with this pump design in a tremendous variety of industrial applications,” says DESMI. “And that’s every bit as important to prospective buyers as the quality and functionality of the pumps themselves. At the end of the day, it’s this depth of experience that ensures high safety levels as well as maximum returns on the investment.”

All the options
DESMI seems to have thought of all the angles for its top-of-the-line pumps. For substances that need to be cooled, an integral pump eliminates the need for external cooling. And for those that like it hot, optional external heating jackets can be added, enveloping the pump’s front cover and magnetic coupling housing.

There’s a choice of materials, too. Slide bearing materials, for example, vary from cast iron, bronze, carbon to tungsten carbide. The magnets themselves are made of neodymium-iron-boron, and optional samarium cobalt permanent magnets allow operating temperatures as high as 250o Celsius. And both internal and external canister protection is offered.


Increasing demand
Market-leading companies such as BASF, Huntsman and Bayer have long been using ROTAN® technology from DESMI, but they’re not the only ones to see its advantages. And in many cases, companies approach DESMI to replace existing double-seal solutions that can’t live up to the task.

There’s never been a better time for ROTAN®-style pumps,” says DESMI. “We’re installing them, for example, in increasing numbers to Asian markets, as well as emerging markets on the African continent. In China, for example, ROTAN® technology has quickly become accepted not just for large enterprises, but for smaller ones, too. Basically, the need for optimum safety is the same no matter where you operate.”


In China, Guangzho Strong Chemical Co., Ltd, a leading domestic producer of automotive refinish coating material, is a recent customer for DESMI’s pumps. Facing increasing demand for its product, the company expanded production capacity with a new factory in March 2014. After careful evaluation of the ROTAN® ED pump’s technical advantages, its total lifecycle, and the safety track record DESMI was able to document, Guangzho joined a fast-growing list of ROTAN® technology adopters in the region.

Guangzho were interested in a complete pump solution that could take into account liquid properties and the piping layout,” explains DESMI. “So we held numerous meetings with both the company and its engineering supplier to understand more about their needs. It’s the only way to arrive at a great solution – and the results speak for themselves.”

DESMI is continuing to upgrade its ROTAN® pump line-up, following growing market demand, and keeping businesses and people safe with this well-proven technology.