In many applications, metering ingredients in the pharmaceutical or food industry for example, pumps are required that not only can be precisely controlled in terms of flow rate and dosing time, but also convey the ingredients particularly gently.
To enable the proven pump units of the ecodos series from LEWA GmbH to fulfill this demanding task with even more flexibility and energy efficiency in the future, the manufacturer is expanding the portfolio to include a new form of wide-range speed control. Alongside asynchronous motors and servomotors, permanent magnet synchronous motors, or PMSMs for short, are also used now. They are characterized by high energy efficiency and a control range greater than 1:200. This significantly expands the range of applications. With PMSMs, it is no longer necessary to use several pumps for different flow rates or oversize asynchronous motors for low speeds. Since PMSMs can be designed without a fan, they remain compact and easy to clean. The latter feature predestines them for hygienic applications. High efficiency rating over the complete control range in accordance with energy efficiency class IE5+ also reduces energy costs, thus ensuring a lower total cost of ownership (TCO).
The diaphragm metering pumps in the LEWA ecodos series are particularly well suited for applications in the food or pharmaceutical industries. All materials in contact with the fluids used in the pump units meet the FDA and USP Class VI requirements, and the EU directives for the food industry. In the hygienic version, for example, the pump head is made of PP or electropolished stainless steel with a surface roughness < 0.5 µm. This facilitates cleaning of the surfaces in contact with the product.
The motor technologies used to date have had to make sacrifices: “For classic asynchronous motors whose rotor is a squirrel-cage rotor, the control range remains limited to 1:10 (1:50 is possible in individual cases). With encoder feedback, significant expansion is possible,” said Maurice Wirkner, an application manager at LEWA. “In addition, the drive is relatively inefficient outside the rated speed range – especially at low speeds. This requires the drive to be oversized, which increases operating costs.” Servomotors are optimized for highly dynamic requirements and also cover the complete control range (1-210 pump strokes), however, they are more expensive to purchase and in addition, require a servo inverter for control.
Wide-range speed control with permanent magnet synchronous motor extends the range of applications
It also features a high short-term overload capacity, which enables a drive design without oversizing for the starting torque. As a result, smaller, more cost-efficient sizes can be realized than with classic drives. “Like the asynchronous motor, the PMSM can be controlled via a standard frequency converter, so users can rely on common parts,” Wirkner explained. “With the servomotor on the contrary, it would be necessary to purchase expensive servo controllers.” The compact drive can be easily cleaned due to its fanless design and offers high IP protection. If required an additional conversion process – called nsd tupH – can be applied to the aluminum body for FDA requirements. This makes the surface extremely resistant and even easier to clean – ideal for applications with stringent hygienic requirements, such as aroma metering in the food industry or additive dosing in the pharmaceutical industry.
IE5+ PMSM enables cost reduction and decentralized solutions
The sole limitation of the currently used PMSM is that it is only available for safe areas. “Thanks to wide-range speed control with IE5+ PMSM, we can meet the increasing customer demands for a wider adjustment range and lower energy consumption, as well as overall costs,” said Wirkner to sum up the situation. “The topic of energy efficiency in particular is becoming increasingly important for our customers. A decentralized solution in which the frequency converter is installed directly on the PMSM, can now be implemented with Getriebebau NORD GmbH & Co. KG, LEWA’s motor partner for PMSM, too.”
LEWA GmbH was founded in 1952 by Herbert Ott and Rudolf Schestag as a family business and is today the world’s leading manufacturer of metering pumps and process diaphragm pumps as well as complete metering packages for process engineering. Headquartered in Leonberg, the company developed into an international group in just a few decades. Since 2022, the company has been part of the Atlas Copco Group, a globally leading Swedish manufacturer of compressors, vacuum solutions, generators, pumps, power tools and assembly systems. Together with the new owner, LEWA will further expand the industrial pumps business. As a research and manufacturing company, LEWA develops technologies and provides solutions for the vast array of applications among its customers. Its products are used mainly in the chemical industry, the cosmetics industry, pharmaceuticals and biotechnology, food and beverage industry and energy utilities as well as in the production of plastics, detergents and cleaners. Additional application areas include refineries and petrochemicals, the oil and gas industry, and gas odorization. LEWA currently employs around 1,200 people and owns 14 subsidiaries around the world alongside having 80 representatives and sales offices in more than 80 countries.