About Harrel, Incorporated...

Harrel, Incorporated is the only manufacturer in the industry that was not originally a machine shop. Harrel came out of the systems business. Incorporated in 1958, Harrel was formed to bring to the industrial area some of the dramatic advances in systems control techniques which came out of World War II and the immediate postwar period. It has specialized from the start in hi-tech equipment and systems. Harrel now occupies a well-equipped 34,000 sq ft facility in East Norwalk, CT. This includes a 3500 sq ft plastic Development Laboratory which Harrel uses to develop and demonstrate such exclusive systems as TUBETROL, PROFILE-TROL, SHEETROL, ULTRATHERM, AND DUOSENSE.

• Harrel introduced the first 3-mode (PID) temperature controllers to the plastics field, in 1967.
• Harrel introduced and patented DUOSENSE, the first dual-sensor temperature system for extruder barrels which maintains the accuracy of the deep well system and still has the advantage of fast response of the shallow well.
• Harrel introduced the first Plant-wide Control and Management system to the Plastics industry (1968)
• Harrel introduced the first microprocessor control system for total control of an extrusion line (1975)
• Harrel was a pioneer in the application of the melt pump to extrusion in a one-on-one basis.
• Harrel developed the GEARTRUDER -- a combination of a rugged extruder, a melt pump, and digital drives, all on one rugged base, together with a DIGIPANEL microprocessor controller to tie it all together and make it operate as an integrated system, instead of a collection of components.
• Harrel developed and patented TUBETROL, the only system available to control both the OD and the ID of tubing of any size and any material.
• Harrel developed what is still the only fully integrated extrusion line for "bump" tubing, which controls both OD and ID of both bump and stem.
• Harrel developed the first coextrusion system which not only controls both OD and ID of tubing, but also controls the thicknesses of each of the layers.
• Harrel is the only U.S. company offering a system for making tubing as large as 2" diameter with very thin walls (18 mils or less)
• Harrel pioneered with its DUOSTREAM system to produce two closely controlled strands of tubing or profile instead of just one
• Harrel developed its exclusive ALTERNATE POLYMER SYSTEM, which can produce continuous tube which varies seamlessly from 100% of polymer A to 100% of polymer B, and still preserves close, closed loop control of dimensions.
• Harrel developed the first all-digital nuclear thickness gauge. Previous gauges had used less accurate analog detectors.
• Harrel developed and patented its exclusive SHEETROL III system, which provides close control of sheet thickness.
• Harrel pioneered in close closed loop control of sheet profile in both machine and transverse directions with its ULTRATHERM system.
• Harrel developed and patented its JACKRABBIT concept of scanning for sheet thickness, to speed up cross-machine measurement.
• Harrel developed the exclusive ROLLERPULLER to eliminate the variations in speed which occur in caterpillar type pullers.
• Harrel was the first to offer a cutter without either clutch or brake -- in its NOCLUTCH cutters. Accuracy and reliability are enormously improved over conventional cutters.
• Harrel developed and patented a system of controlling polymer viscosity on-line.
• Harrel developed the VISCOTRUDER which solves the problem that viscosity data obtained from most viscosimeters is not applicable to actual extrusion.