OMS Group claims it is helping sandwich panel manufacturers save hundreds of thousands of dollars a year with more energy- and chemical efficient technology.
According to the Milan, Italy-headquartered machinery group, producers of flexible-faced, insulated roofing panels have seen a 10-percent drop in chemical costs and significant savings in maintenance needs and energy use after upgrading existing production lines to new high-speed OMS laminators.
Mark Clark, general manager of Polyurethane Process Industries — OMS’s exclusive distributor in the US, said, “Several US and European panel manufactures replaced their old mixheads and chain-driven laminators with new OMS high-pressure mixheads, high pressure heat exchangers, and gear-driven double-belt conveyors.” The whole OMS laminator is fully enclosed to inhibit heat loss during curing, said Clark, adding that the conveyor is also chainless, which means significantly lower maintenance costs and less friction, “so OMS can use smaller drive motors that use less energy.” Clark said other manufacturers of continuous flexible- and rigid-faced sandwich panels could make similar savings with the OMS mixhead and laminator upgrades. These include:
• A lay-down area where three self-cleaning, recirculating mixheads distribute multiple streams of reacting foam onto a flexible or rigid substrate. Pneumatically controlled nozzles on the high-pressure mixheads automatically adjust to maintain a set pressure, PPI notes. The mixheads improve chemical utilisation by: better control of chemical temperature and pouring pressure; dynamic blending of variable amounts of polyol, catalyst, blowing agent and other additives; impingement mixing; and foam distribution.
• High-pressure heat exchangers near the mixheads that give more accurate control of chemical temperature where needed.
• A double-belt conveyor that precisely maintains the required dimension of the finished panel as it transports the substrate and foam core through the curing process.
Automatic adjustment of the upper belt position precisely maintains or varies panel thickness without no need to stop the line to insert spacers. Hot air circulates within the conveyor, which is enclosed within a thermally insulated tunnel to conserve heat and energy.
“This technology is standard on OMS continuous panel lines,” Clark said, adding that, “The new mixheads and high-pressure heat exchangers typically pay for themselves in a year by reducing the amount of scrap and chemicals used.” Clark said there are other advantages built into OMS panel production technology.
“Dynamic mixing with high-pressure recycle allows you to change formula for product thickness, and it provides a better polyol/pentane mix, reducing the possibility of emulsion separation,” he noted.
“You want the pentane dispersed evenly throughout the foam mixture, otherwise you could end up with blisters,” Clark said.
Latrobe, Pennsylvania-based PPI has seen rising interest in producing insulated sandwich panels, as investors and manufacturers turn their attention to green products, Clark said.
“Recently, we’ve been pretty busy upgrading existing production lines,” Clark said. “But we’re also in the best position to help someone get started in the manufacturing of insulated panels of all types.”
Save up to $200 000 says expert
Lynn Haas of J.L. Haas Consulting agrees that OMS panel production technology offers significant\cost savings over equipment from other suppliers. Haas has 30 years’ experience working with and selecting equipment for insulated panel production.
“To maximise yield, the expanding chemicals should be distributed evenly over as much of the surface as possible,” Haas commented. Compared to a standard two-head system with manual highpressure controls, the OMS three-mixhead system with pneumatic pressure control distributes a third more well-mixed reacting chemical on the substrate.
“This improvement may increase chemical yield by 5 to 6 percent in 1-inch board and 1 to 2 percent in 2-inch board,” Haas said. “With an average product thickness of 2 inches and a wet density of 1.90 pcf, the savings on 100 million board feet could be in the range of $150 000 to $200 000.” High-pressure temperature control, highpressure recycling and self-cleaning mix heads all help produce higher quality foam, less scrap and less maintenance downtime, Haas said. “Imagine cleaning the mix head once every 3 months.” High-pressure heat exchangers close to the final mix point give more uniform chemical reactivity, reducing over-pack and under-fill of the panel, Haas said. “High-pressure recycling can eliminate three to eight reject boards during start-up, just by allowing the line to start with pre-determined temperature, blowing agent and catalyst levels.” Panel makers can cut costs even more if panel thickness is automatically adjusted, as is standard on the OMS laminator. “Mechanical thickness adjustment has a major benefit over manual adjustment when it comes to reducing chemical usage, downtime for change-over and thickness errors due to incorrect spacer placement,” he said.
Systems that require an operator to stop the line to insert calibration spacers typically provide a minimum thickness adjustment of 1/32 of an inch, Haas said. This can waste a significant amount of chemical because panel thickness may vary from exactly right at the minimum specification to 0.03124 inch over the specified thickness.
The thickness of a 2-inch panel could be, on average, 0.015 inch thicker than required. “You can easily waste 0.75 percent of total chemical usage over a year. Each 100 million board feet produced, at $1.0/lb of chemicals, would use as much as $120,000 more chemicals than needed,” he said.
Motorised jackscrews on the OMS double-belt conveyor automatically adjust to maintain the panel thickness to the minimum specifications. “With automated thickness, in theory, you could start the day producing minimum thickness product and never stop the machine until that product is finished,” Haas said.
Not only can this save hundreds of thousands of dollars in chemicals, but product thickness changes during normal shutdowns can be made in two minutes or less, saving from three to six minutes for each product change, Haas said. In a 5-product shift, that is 15 -30 min more production,” Haas said. “At 30 min, change-over time represents 6 percent excess downtime in an 8-h day.” Automatic thickness adjustment also eliminates “spacer errors,” at $600 to $700 a time, Haas said.