Cast-In Liquid Cooled Heaters are the most common cast -in heater design used on plastics extrusion barrels. The liquid cooling tubes run symmetrically to the heater element, which provides a uniform cooling pattern across the body of the casting. This cooling function dissipates heat rapidly from the cast-in barrel allowing a tight control of the melt temperature during operation. The typical liquid cooled design features a single 1/2 ” diameter cooling tube of stainless steel or nickel alloy. The tubes can be supplied with no termination and plumbed at the location of the equipment, or other termination options such as cast-in threaded fittings can be supplied to minimize installation time. This cast-in design is also available with a dual cooling function. Although slightly larger in thickness, this design allows for a second cooling tube assembly, which can be employed, if the initial cooling line fails due to scale build up or cracking due to corrosion. All Durex cast-in barrel heaters are available with mounting options of stainless steel locking straps or bolt-on clamping construction. Various electrical termination options are available depending on the application or environmental requirements.
Liquid cooled cast-in heaters are designed to combine the function of heating and cooling the barrel during the extrusion process. These cast barrel heaters are available with a wide range of standard and custom options for maximizing machine operations using various material types.
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| Cast Materials | MaximumOperating Temperature |
| Aluminum 443 | 800°F (427°C) |
| Aluminum 319/356 | 700°F (371°C) |
| Bronze / Copper Alloys | 1400°F (769°C) |
| Iron | 900°F (482°C) |
If required, other cast materials are available.
Cast Processes – Durocast™ perm-mold system uses steel permanent molds. No bake sand system for special castings and short production runs.
Machine Finish – CNC machining is performed for tight tolerances and complex configurations. Milled finishes are provided per specification. Belt sanding, lapping and polishing available to meet application specifications.
Standard Machine Finish Range: 64 to 125 rms.
Fine Finish Per Specifications: 8 to 32 rms.
Standard Flatness: Belt sanded, .015, Milled .005, Lapped, .001
Holes, Cutouts, Thermowells – Mounting or clearance holes, cutouts and thermowells, for inserting temperature measurement probes, cast-in or machined per your specifications.
Inserts – Threaded studs, precision component parts, bushings and special design parts cast acccurately in place.
Electrical – Resistance tolerance NEMA standard +10% -%5
Voltages:
| Element diameter | .200 | .260 | .315 | .430 | .475 |
| Maximum volts | 240 | 240 | 277 | 600 | 600 |
Three phase available on large heaters. Maximum watt densities depends on size and application. Consult a Durex Engineer.
UL Component Recognition – DA Series cast in heaters are recognized per file E110394.
Inspection/Testing
