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6/1/2000 | 4 MINUTE READ

RIM & Urethanes

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Improved designs of high- and low-pressure metering systems will be displayed at NPE 2000. Look also for new CO2 blending systems and an upgraded pentane mixing system.

High-pressure systems

A self-cleaning, recirculating mixhead for PUR spray into open molds will be introduced at the show by Gusmer-Admiral Inc., Akron, Ohio. The MiniRim spray head is said to be the first recirculating mixhead designed specifically for open-mold spraying in applications such as car door interiors, building panels, and furniture. Previously, PUR processors had to settle for a mixhead that was simply an altered version of a standard pouring head. The drawback is that such heads must be flushed between shots with pressurized water, adding to cycle times and creating polyurethane resin waste. The nozzle mechanism of the MiniRim spray head is designed to expel any urethane residue from the chamber and cavity automatically without a purge cycle.

In addition, this spray head is said to disperse the foam in a wide, uniform path, reducing the number of times the head must pass over the mold to complete the deposition. It offers molders a way of covering large areas quickly and efficiently with precise control of overspray. The fan spray pattern can be adjusted by the choice of nozzle tip and by changing the distance of the mixhead from the face of the mold.

Another new mixhead is reportedly capable of handling small throughputs not previously possible with high-pressure impingement heads. The MHL 3/5 head from Linden/EMB, Cuyahoga Falls, Ohio, provides a shot range from 5 to 38 g/sec. The 180° L-type head is said to offer exceptional performance in production of microcellular and flexible foams.

Also exhibited by Linden will be the Micro-Innovator high-pressure metering unit for small parts. It is available in two models with output ranges from 10 to 100 g/sec and metering accuracy of ±1% at standard mixing pressure of 3000 psi. The unit’s controls are equipped with Linden’s Hotline modem service support system. Besides allowing for remote data analysis and assistance with processing problems, this system enables the company to upload or download a PLC program if necessary.

Krauss-Maffei Corp., Florence, Ky., will highlight its new RIM-Star Plus high-pressure metering system with an all-on-one frame design that incorporates day tanks, metering systems, and electrical controls. Placing the heat exchangers inside the day tanks is said to result in superior temperature control. The new control system has high-speed data-highway interconnections. It also features the new PUC 07 data-acquisition system, which can control up to 16 machine components simultaneously, while recording process parameters, monitoring tolerances, and logging faults/events. The system is compatible with various PLC brands.

A long-time specialist in repair of high-pressure mixheads, MHR Inc. (Mix Head Repair & Brokerage), Holland, Mich., has come out with its own line of straight and L-shaped mixheads that reportedly can withstand abrasive additives at pressures to 3000 psi. MHR will also introduce an abrasion-resistant ball valve for high-pressure systems processing glass reinforcements. In addition, MHR is now distributing high-pressure chemical pumps designed specifically for PUR by RHL Hydraulics of the U.K. MHR also offers RHL’s pump-seal kits so that users can maintain and reseal the pumps themselves.

Foam with CO2, pentane

Linden/EMB is launching Gas Infusion, its newest system for introducing CO2 into polyol or isocyanate. Working with tank blanket pressures as low as 40 psi, this stand-alone metering unit reportedly can be installed quickly and easily on existing PUR systems. It continuously monitors and adjusts the CO2 level, which is said to be more accurate than periodic sampling.

With its new RIM-Star Plus high-pressure machine, Krauss-Maffei will show the new GBE 2000 gas-nucleation unit. It can handle CO2, air, or nitrogen.

Hi-Tech Engineering, Inc., Grand Rapids, Mich., will display its new Carbo-Mix premixer, which dissolves CO2 in isocyanate. During mixing, a PLC provides continuous control of CO2 output and also of the pressure and temperature of the mixture.

The company will also exhibit its newly upgraded Pentafoam HP pentane mixing/metering unit, which dynamically blends pentane with polyol. The new unit is a product of High-Tech’s joint venture with the OMS Group of Italy. The redesign mainly involves improved safety features.

Low-pressure machines

Low-pressure processing without solvent flushing will be demonstrated by Decker Industries, Inc., Palm City, Fla. Decker will show its new ParaDyne compact, in-line static mixer that uses disposable mixing elements. Its design reportedly minimizes dripping during the indexing sequence on a production line. This patent-pending technology uses a simple method to pull the mixed material back into the mixer between shots without complicated and ineffective mechanical snuff-back valves in each material line. This pull-back action quickly decompresses the mixer chamber and holds material inside the mixer until the head can be indexed to the next part.

Cannon USA, Cranberry Township, Pa., will show the latest addition to its b-Series low-pressure metering machines. This model has a submerged metering pump in each of the component tanks. This both eliminates potential leakage into the air and drastically reduces maintenance, Cannon claims.

The Eco Cleaner, a new flushing unit for low-pressure systems, will also be shown by Cannon. It can process environmentally friendly flushing agents and recycle them for reuse.

Adhesives Systems Technology Corp. (AST) Corp., Minneapolis, is introducing the DMS Series dynamic mixer for flexible and rigid urethane and silicone foams. It can dispense a preprogrammed amount in a specified pattern. It dispenses from 2 to 120 cc in a viscosity range of 1 cp to 2 million cp. The DMS uses piston and gear metering pumps and can process abrasive materials. It comes with a material transfer pump, material agitation and nucleation, temperature controls, and ratio check. Options include automatic purge, x-y-z motion, turntable, automatic material refill, and closed-loop ratio control.

Gusmer will show what is said to be the first recirculating high-pressure mixhead designed for spraying into open molds.

Decker’s ParaDyne mixer accomplishes low-pressure processing without need for solvent flushing.

Linden/EMB’s MHL 3/5 high-pressure mixhead handles very small throughputs.