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Linde unveils improved pressure booster

By: Roger Renstrom

April 16, 2012

ORLANDO, FLA. (April 16, 1:10 p.m. ET) — Linde LLC introduced a Presus N10 high-pressure liquid-nitrogen pressure booster at NPE2012 to help gas-assist injection molders improve efficiency and quality.

Parent firm Linde AG, an international industrial gases and engineering company, conducted beta tests with potential customers in Germany, the Czech Republic and Poland after one site conducted trials with a prototype beginning in 2010.

In the initial test, injection molder Engel Formenbau und Spritzguss GmbH of Sinsheim, Germany, worked with the Presus N10 prototype in an effort to reduce scrap and downtimes and shorten cycle times.

“We are seeing interest in the pressure-boosting device,” said Andreas Praller, plastics industry applications manager for Linde in Unterschleissheim, Germany.

The liquid pump can boost nitrogen to 4,500 pounds per square inch and deliver flow rates up to 4,600 cubic feet per hour. The highest flow rate is about five times higher than state-of-the-art gas compressors.

Separately, Linde in North America targets manufacturers of extruded polystyrene foam for a precise-dosing 7,250-pounds-per-square-inch metering system.

Linde’s patented DSD 500 system reduces the use of hydrofluorocarbon and hydrochlorofluorocarbon blowing agents with the controlled addition of precise amounts of carbon dioxide through a proportional control valve. The system keeps carbon dioxide gas consumption low.

Many foam manufacturers in Europe use the DSD 500 system and related pressure boosters.

Linde makes it easy for foam manufacturers to capitalize on the advantages of using carbon dioxide while avoiding hydrocarbon foaming agents, said James Stanley, recently named program manager for industrial applications with Linde LLC in Murray Hill, N.J.

The company offers a way for spot cooling of injection molds with liquid carbon dioxide as a supplement to conventional cooling.

The system can cool hot spots in a mold and improve production of very thin parts, molds with small cores or areas with material accumulations. Use of carbon dioxide can reduce cooling and cycle times, perhaps as much as 50 percent.

Linde provides the spot cooling feature to automotive makers in Europe and is starting to introduce the concept to those in the U.S. automotive and medical markets.

Linde’s development of the spot cooling technology began about six years ago, but “we needed to convince customers that it gives them more flexibility,” Praller said.

For the plastics industry, Linde’s cryogenic gas technology can provide rapid cooling using an inert gas such as carbon dioxide or nitrogen for molding, extruding and foaming applications.

Globally, Munich-based Linde employs about 50,500 and had 2011 sales of 13.9 billion euros ($18.1 billion).

Presus N10 high-pressure liquid-nitrogen pressure booster aids gas-assist injection molders