U.S. pipe extruders are more willing to invest in new technology as they face tougher competition and higher resin prices, according to Siegmar Schmidt, the top U.S. executive for auxiliary equipment maker Inoex GmbH.
``Traditionally in the U.S. pipe business, companies would tend to buy new technology once everybody else was buying it,'' Schmidt said. ``In the market, as the mentality is changing, the philosophy also is changing. People are looking to invest to maintain margins.''
Inoex, which employs 130 in Bad Oeynhausen, Germany, makes dosing equipment, gravimetric blenders and other measurement and control equipment for extrusion. At the 2004 K show in Germany, Inoex gained attention for its Advantage, a sleevelike device that quickly changes the diameter of plastic pipe without stopping the line.
Schmidt, president of Inoex LLC, the U.S. operation in Lancaster, Pa., outlined some new technologies, including MaxFlexx interior pipe cooling, and a faster way to cross-link polyethylene pipe inline called Pexlink. A third lab line runs the Advantage system.
During a mid-August interview at Plastics News offices in Akron, Schmidt said the push for new technology has helped Inoex gain U.S. business even as the construction slowdown has hit pipe extrusion.
To change pipe diameter, the Advantage uses a flexible sleeve with interlocking parts that maintain a stable round shape. When the end of the sleeve is pulled, the diameter becomes smaller, as Advantage squeezes down the pipe as it comes out of the die. Advantage also can be used to change wall thickness by altering throughput or changing line speed.
Now Inoex is expanding the Advantage product range to handle pipe in diameters up to 24 inches. The previous high was 16 inches. For pipe up to 10 inches, Inoex can change the diameter up to 250 percent. For diameters larger than 10 inches, the top change is 200 percent.
Inoex also continues to push its ultrasonic Aurex system, which uses a series of fixed sensors to continuously measure wall thickness, diameter, shape and layer thickness over 100 percent of the circumference of pipe up to 64 inches in diameter.
The company is touting these new technologies:
MaxFlexx internal cooling. Traditionally, plastic pipe has been cooled from the outside by moving it through a water bath once it exits the die but the interior stays hot.
``So you have it cold outside and hot inside. That builds up a lot of stress.'' Schmidt said. To avoid as much stress as possible, the line must be slowed down, or the bath must be longer.
At an open house this summer, Inoex showed how internal cooling increases pipe output by 35 percent.
By simultaneously cooling from the inside and outside of the pipe, the heat is removed quickly. ``The cooling takes place right when it comes out of the die,'' Schmidt said.
The key is an arrangement of several vortex tubes inside the die. A vortex tube separates compressed air into hot and cold streams. The air moves backward through the tubes, away from the die head, picking up heat.
Hot air leaves through a control valve, where it can be used for drying materials. Then the stream of cool air moves forward through the die and directly inside the pipe.
Pexlink. Inoex officials talked about Pexlink at K 2007, but the first demonstration came at the firm's open house in June in Bad Oeynhausen. Cross-linked polyethylene pipe, known as PEX, is becoming popular for plumbing and radiant floor heating.
Flexlink uses the liquid peroxide method of cross-linking the PE material, but at much faster speeds than the traditional method, thanks to an inline infrared oven developed by Crosslink Oy of Tampere, Finland. Infrared energy penetrates the pipe wall, cross-linking it quickly without waiting for heat transfer through the wall.
After the pipe leaves the oven, equipment measures the degree of cross-linking, again in-line with the pipe production an industry first, according to Schmidt. The closed-loop system feeds information back to the line, to adjust the cross-linking.
Schmidt said that normally, with the peroxide method, cross-linking takes place in the extruder, which must run at slowly for the process to finish before the pipe leaves the extruder.
``With this Pexlink process, we can run much faster because we are doing the cross-linking with the oven. So we can run about 60 feet a minute. This is finished cross-linked pipe, measuring and controlling inline the cross-link degree, and having closed-loop control for the cross-link degree. So every single piece of pipe coming out of there is a good one.''
Inoex supplies the peroxide conveyor station, and dosing equipment for other raw materials.
Also, by linking the infrared technology to Inoex's automatic control equipment, the PEX pipe production line can automatically control pipe dimensions.
MaxFlexx manual pipe calibration sleeve. Inoex bills this as a new, simple version of its Advantage pipe calibration sleeves. By turning an adjustable device, the calibration sleeve permits changing the pipe diameter by up to 6 percent, without changing the sleeve to run pipe of different pressure classes.
The MaxFlexx sleeve works on larger pipe sizes, up to 48 inches in diameter.