Rotary hearth electrical oven heat treats shafts

Edited by the Manufacturingtalk editorial team May 12, 2006

An electrically-heated rotary hearth oven for heat treating machined metal shafts features a digital indicating temperature controller and a manual reset excess temperature controller.

Oven model No 982 is a 1000 deg F, electrically-heated rotary hearth oven from The Grieve Corporation, currently used for heat treating machined metal shafts at a customer's facility.

Workspace dimensions measure 24in W x 11in D x 30in H with a 26in diameter hearth constructed from overlapping steel plates with 24 pipes holding pin inserts to support the workpieces.

24kW installed in Incoloy sheathed tubular heating elements provide power, while a 1000ft3/min, 1HP recirculating blower provides radiant horizontal airflow to the workload.

An additional cooling blower is mounted beneath the loading table to cool the parts in the front middle three positions of the hearth.

The hearth is driven by a 1/4HP motor through a gear reducer with torque limiting device, variable from 0.1 to 0.5 revolutions/h.

A loading table is provided in front of the oven to hold extra pin inserts.

This oven features an aluminized steel exterior and interior, an exhaust hood around the openings in the face of the unit with a 130ft3/min exhaust fan, plus an integral oven leg stand.

The 8in thick wall insulation comprises 2in of 1900 deg F block and 6in of 10 lb/ft3 density rockwool.

Controls on the No 982 include a digital indicating temperature controller, manual reset excess temperature controller with separate contactors, recirculating blower airflow safety switch, fused disconnect switch and a 10in circular chart recorder.