EoW November 2010

Compounds & colourings

Doubling the throughput of additive feeders An advanced model of the Maguire ® MGF gravimetric feeder is said to provide more than double the throughput of the original system, but has the same compact size. Used for feeding colourants and additives into plastics processing machines, the new MGF system is driven by a motor that is smaller than that in the earlier feeder but delivers material at rates of up to 36kg (80lb) per hour, compared with the previous top throughput of 13.6kg (30lb).

Durable, flexible semicon jacketing

Dow Endurance™ DHDA-7708 BK is appropriate for medium, high and extra-high voltage (MV, HV, EHV) applications and can be applied as a thin layer over an existing jacketing grade during manufacture or as a cable jacket extruded entirely of this semiconducting compound. The compound provides a reliable earth (ground) continuity path to allow integrity testing of the cable jacket upon installation or years later. The material can be used in any situation where graphite has traditionally been used, but is a particularly good choice where cables are installed in air, for example, in duct systems or tunnels – or where ground conditions make testing graphite-coated cables difficult. Unlike graphite, Dow Endurance DHDA-7708 BK resists being washed and abraded from the surface of the cable during installation and over years of service. When used as the sole jacketing material, Dow Endurance DHDA-7708 BK provides continuous earthing (grounding) along the entire cable. This affords additional protection from surges and transients, such as lightning. The compound can be used for both land and subsea cables. In addition to delivering the important conductive properties for monitoring and electrical functionalities, Dow Endurance DHDA-7708 BK also delivers excellent protective characteristics required for jacketing over MV, HV and EHV power cables. It provides the mechanical strength and durability of a normal insulating jacket. Compared to conventional thermo- plastic semiconductive materials, this compound is said to offer improved environmental stress-crack resistance, better thermomechanical and low- temperature properties (flexibility in colder climates), easier strippability and stronger cut-through and abrasion resistance. The compound also offers reduced moisture vapour transmission and adhesion to strippable insulation shield – all while reducing system cost at the time of installation and over the life of the cable. DowWire & Cable – Switzerland Website : www.dowwireandcable.com

High-throughput MGF gravimetric feeder

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Also new is a networking option; controllers for the MGF feeders can now be net- worked with Maguire’s Gravimetric Gateway™ or G2™ software. This program provides exhaustive material-usage reports, displays alarms from anywhere in the network, gives access to specific machines from remote locations and monitors inventory levels. “The increased throughput of the MGF feeder increases the applicability of this system without any compromise in compactness and affordability,” said Paul Edmondson, general manager of Maguire Europe. “At the same time, this advanced system enables more companies to obtain the advantages of gravimetric feeders over the volumetric devices that currently dominate the industry. Gravimetric feeders are less complicated, easier to use and more accurate.” The accuracy of the MGF feeder stems from the use of load cells to monitor the loss in weight of colourant in a hopper (mounted on the load cell) as the material is fed into the processing machine by an auger. Software in the feeder control scans data on colour consumption every half-second and automatically adjusts dispensing when a predetermined amount of accumulated error is detected. “By responding exclusively to accumulated error over a given period of time, Maguire’s proprietary software focuses on real changes in throughput, not transitory or anomalous changes caused by vibration, clumping, or surges,” Mr Edmondson said. “Thus the system provides real-time control and smooth metering consistency.”

Maguire Products Inc – USA Website : www.maguire.com

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EuroWire – November 2010