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QD SERIESDual Chamber Hardening/Tempering FurnacesAPPLICATIONSThe QD Series Dual Chamber Heat TreatingFurnaces feature a 2350°F (1285°C) high heatchamber for hardening and a 1250°F (675°C)recirculating oven for tempering. Theover/under configuration saves floor space.The hardening furnace is mounted on topwith the tempering oven below. Agitated andheated quench tanks are optional. Thefurnaces achieve high precision by featuringhighly accurate controls, mercury contactorsfor fast cycle times, two zone control (topand bottom) on the hardening furnace, andvery even spacing of elements. The temperingoven features a powerful fan and recirculationmuffle for high uniformity. The furnaceconstruction is similar to the XLE Series.FEATURESHIGH TEMPERATURE UNIFORMITYThe hardening furnace is uniform to within+/-20°F (+/-11°C) above 1500°F (815°C).The tempering oven is uniform to within+/-10°F (+/-5.5°C) above 300°F (150°C).TWO ZONES AND EVEN ELEMENTSThe elements of each furnace are divided intotop and bottom zones. The elements of thehardening furnace are evenly spaced on thedoor, back, sides and bottom. The elementsare supported in proprietary ceramicelement holders. These provide perfect supportfor the coiled element as well asexcellent radiating characteristics. Thesmooth surface prevents premature failure ofthe element as it expands and contracts.Iron-aluminum-chrome alloy elements arestandard.EFFICIENT MULTILAYERED INSULATIONBoth chambers are insulated with 4-1/2” oflow K factor refractory firebrick as theprimary insulation.This is backed up by 2” ofvery low K factor mineral wool board on allsurfaces except the bottom which has 2” ofhard calcium silicate back up for solidhearth support. This yields an excellentcombination of strength, insulating qualityand fast heat up and cool down time. Allrefractory is coated with a special facingthat prolongs firebrick life and helpsprevent spalling and dusting. The refractorysections are available completely shapedfor easy replacement without cementing.HEAVY DUTY CASEBoth chambers are mounted in anintegrated 10 gauge steel case withstiffeners, leveling bolts and lifting rings.DOUBLE PIVOTED DOORSBoth doors are double pivotedhorizontal doors with insetrefractory plugs for a superbheat lock around the door seal.The double pivoting allows thedoor to be opened so that thehot face stays away from theoperator. Vertical door forhardening furnace (as shown inphotograph) is optional.FAN AND RECIRCULATIONMUFFLE IN TEMPERING OVENThe tempering oven features a back mountedalloy fan. It is belt driven with a 3/4 hp motor. Aheat dissipator protects the bearings. Theremovable recirculation muffle is constructed of304 stainless steel. This has a solid bottom for useas the hearth. The muffle protects the work fromdirect radiation of the elements and creates arecirculation pattern for the air. The hardeningfurnace comes with a ceramic hearth.DIGITAL HONEYWELL PID CONTROLSStandard controls are Honeywell UDC2300digital PID controls. All fuses, transformers,switches, contactors and controls are housedin a NEMA 1 panel. Quiet, long life mercurypower contactors are standard. Limit switchesshut off furnace power when doors areopened or the backs are removed. LightedNEMA 13 on/off switch is included.OPTIONS● NEMA 12 PANEL OPTION: Includes a fuseddisconnect switch.● HIGH LIMIT CONTROLS● HIGH KW: Available on hardening furnace.● SCR POWER CONTROL● INERT ATMOSPHERE CONTROL● RAMP/SOAK PROGRAM CONTROLS● TEMPERATURE RECORDERS● VERTICAL DOORS● SILICON CARBIDE HEARTHSThis QD 236 features apneumatic vertical door,atmosphere sealed caseon top, NEMA 12control panel and stripchart recorder.QD SPECIFICATIONSHARD CHAMBER HARD CHAMBER TEMP CHAMBERACTUAL UNIFORM INSIDE RECIRC OUTSIDE HARDEN TEMPER MAX APROXMODEL INSIDE DIMENSIONS INSIDE DIMENSIONS MUFFLE DIMENSIONS DIMENSIONS CHAMBER CHAMBER LOAD SHIPNUMBER IW IH ID W H D IW IH ID OW OH OD KW KW WEIGHT WEIGHTQD 524 16 18 25 12 11 20 11 11 20 54 75 56 13.5 10.0 110 2000QD 814 19 15 25 15 9 20 14 8 20 57 72 57 14.0 10.0 125 2300QD 824 19 21 25 15 15 20 14 14 20 57 84 57 17.0 12.0 150 2700QD 836 19 21 37 15 15 32 14 14 32 57 84 69 22.5 17.5 200 3300QD 236 25 21 37 21 15 32 20 14 32 63 84 73 27.0 21.0 300 3500Dimensions are in inches. Weight is in pounds. Standard voltages supplied are 480, 240, 208, 380 and 575. Three phase or single phase is available. Inside temperingchamber dimensions are also working dimensions for that chamber.Page 10www.hotfurnace.com