XLE SERIES

PRECISION ELECTRIC
BOX FURNACES
2350F (1287C)

APPLICATIONS

The XLE Series are highly uniform and controllable electric box furnaces widely adaptable to many applications. In the heat treating field these include hardening, neutral hardening, solution heat treating, stress relieving, annealing, aging, precipitation hardening, and tempering. In the ceramic field applications include ceramic bisque firing, thin film processing, glazing, and decorating. Brazing, calcining, drying, melting of glass and metals, glass annealing and bending, enameling, and sintering are just some of the other applications XLE furnaces are used for. Although "standard" configurations are made, each furnace is normally fitted with standard and special options to suit specific needs. These include vertical doors, fans, cooling venturis, vents, special hearths, racks, baskets and loading devices, quenching systems, various controlled atmospheres, retorts, viewing ports, special element alloys, special thermocouples, various kinds of alarms, program controls, and recorders.

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A PHOTO SHEET SHOWING
VARIOUS XLE FURNACES
AND OPTIONS

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A SPECIAL XLE FURNACE
WITH EXTERNAL AIR QUENCH
AND PROTECTIVE ATMOSPHERE
FOR NEUTRAL HARDENING
OF AIR HARDENING TOOL STEEL

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FEATURES

FAST HEAT UP & COOL DOWN
An empty furnace will heat up to 2000F (1093C) in approximately 1-1/2 hours. The high K.W. (superpower) option will trim this to 1 hour. Cool down to 500F (260C) is approximately 5 hours. Optional 300 or 600 CFM venturi will speed cooling.

EXCELLENT UNIFORMITY
The furnace is uniform to within +/-20F (+/-10C) above 1400F (760C) within the Uniform Working Dimension (see specification chart). Optional fan systems are available for tighter uniformity of up to +/-5F.Tighter uniformity is also achieved by reducing the working dimensions and with multi-zoning.

TEMPERATURES TO 2350F
With optional nickel-chrome elements the maximum temperature is 2100F(1134C.) Some options such as fans and other alloy components may also limit the temperature.

PRESHAPED BRICK SECTIONS SAVE ON HEAT LOSS AND MAINTENANCE COSTS
The refractory is cemented in sections on a very flat table. These sections are then precision cut and routed. All sections fit together with engineered heat locks which improve the insulating integrity of the furnace even after many years of service. Brick sections can easily be installed by in-house maintenance personnel saving on expensive specialized bricklayer labor.

EFFICIENT MULTILAYERED INSULATION
The furnace is insulated with 4-1/2” of low K factor refractory firebrick backed up by 2” of very low K factor mineral wool board on all surfaces except the bottom which has 2” of hard calcium silicate back up for solid hearth support. This yields an excellent combination of strength, insulating quality, and fast heat up and cool down times. The roof of all models which are 24” wide or above is made from 2600F ceramic fiber modules to prevent roof failure.

LOW WATT DENSITY ELEMENTS FOR LONG LIFE
The standard elements are coiled from high grade iron-aluminum-chrome alloy (Kanthal A-1 or the equivalent). Nickel-chrome (80-20), Chromel AA, and other alloys are available for special atmospheres and applications. A watt density normally below 10 watts per square inch maximizes element life. (Watt density is the ratio of watts to square inches of radiating surface area.)

EVEN ELEMENT PLACEMENT
Each element is separately and evenly spaced on the bottom, sides, door and back. This is the finest method of distributing radiant heat energy at high temperatures.

CERAMIC ELEMENT HOLDERS
The elements are supported in proprietary high temperature ceramic element holders. These provide perfect support for the coiled element and excellent radiating characteristics. The smooth surface of the holder prevents premature failure of the element as it expands and contracts. These holders, coupled with a unique all ceramic element terminal, make element replacement easy. Being recessed into the wall of the furnace these elements are not as susceptible to mechanical damage as some other types of element support systems.

HEAVY DUTY CASE WITH INTEGRATED STAND
The furnace case is constructed of 10 gauge steel with external bracing angles welded to the entire case and base assembly. Leveling bolts, anchoring holes and lifting rings are included. The main seams are continuously welded for an attractive appearance. The entire case is primed inside and out with a high temperature (800F) silicone based paint. The final coat is a heat resistant light gray-green enamel. Custom colors are available. Sealed cases for controlled atmosphere use are optional.

DOUBLE PIVOTED PLUG DOOR
The standard door is a double pivoted horizontal plug door. The double pivoting allows the door to open like a parallelogram which keeps the hot face from the operator. There are two heavy duty clamps for tight sealing. Because of the completely horizontal motion of the door as it is sealing there is no wear on the seal face. The door has a 3/4” refractory plug which protrudes into the furnace chamber and provides a highly effective heat lock. There is a 3-1/2” refractory to refractory seal around the perimeter of the door. Counterbalanced vertical doors with hand crank, pneumatic or electric actuator are options. Vertical doors lift away from the furnace seal before lifting up. They also include a heat locking plug.
CERAMIC ELEMENT TERMINALS
Unique L&L designed all ceramic element terminal blocks allow the element ends to be clamped without twisting the whole end around a terminal bolt, making it easy to remove an element. The connection wires can be easily removed without disturbing the element termination (which allows you to easily isolate an element for a resistance check.) The terminal block features superb electrical isolation characteristics.

A WIDE VARIETY OF HEARTHS
The standard hearth is one or more 3/4” thick ceramic plates elevated on ceramic blocks 1-1/2” above the bottom elements. This air space improves uniformity. Silicon carbide plates, alloy plates, roller hearths, baskets, racks, loaders, castable piers, air cooling tables and many other loading options are available.

SIDE MOUNTED CONTROL PANEL WITH HINGED DOOR HOLDS ALL COMPONENTS
All temperature controls, relays, contactors, power controls, switches, transformers and fuses are located in a side mounted NEMA 1 control panel with a gasketed hinged door. J.I.C. wire coding is used throughout. An oil tight NEMA 13 lighted on/off push -button switch turns the furnace on. Controls are mounted at eye level for easy visibility. A NEMA 12 panel with fused disconnect switch is optional. A cooling fan is included with SCR power controls.

DIGITAL HONEYWELL UDC 2000 PID TEMPERATURE CONTROL
A Honeywell UDC 2000 microprocessor based digital single set point control is standard. Two full vacuum fluorescent displays include English language programming information for easy set up. This is one of the easiest digital controls to operate. Accuracy is .25% of scale. All PID tuning constants (proportioning band, reset, rate) plus maximum temperature, scale range, thermocouple type and many other parameters are programmable. Ramp/Soak programming is optional. Many other controls are optionally available.

DIGITAL HIGH LIMIT CONTROL
A Honeywell UDC 2000 digital high limit control, complete with back up contactors and separate thermocouple, shuts off furnace if temperature or power control fail. The digital control allows a maximum temperature to be programmed into the control.

MERCURY CONTACTORS FEATURE FAST CYCLE TIME FOR ACCURATE CONTROL
Other benefits are long contactor life and quiet operation. SCR power controls are optional.

TWO ZONE CONTROL FOR CLOSE GRADIENTS
The elements are divided into top and bottom zones. The control output is routed through two input switches to allow adjustment of the total time on to each zone. There are thermocouples mounted top and bottom with a selector switch to read the differential. Special designs with up to six zones or more can be used to promote even greater temperature uniformity.

TYPE K THERMOCOUPLES WITH SHIELDED EXTENSION WIRE
Type K open thermocouples are standard. All thermocouple lead wire is shielded from electrical noise and grounded to a common ground. Lead wires are carefully run to avoid interference from power wiring. Inconel sheathed Type K are a commonly supplied option. Type R and Type S platinum thermocouples are also optional.

MANY SAFETY FEATURES
Thermocouple break protection is included. Limit switches shut off power to furnace if the door is opened or the power panel back is removed. Control voltage is transformed to 120 volts. The control and branch power circuits are fully fused.

BUILT IN RELIABILITY
The furnace is warranted for one year except for the elements and thermocouples (six months.) The control system is burnt in and calibrated at actual operating temperatures in a test furnace and a recording of this test is provided. As a result of having made a large number of these furnaces, the engineering thought and detail devoted to this series is extensive. L&L has paid great attention to small details, interchangeable parts, serviceability, reliability, adjustments, documentation and instructions . The design has continuously evolved over 40 years.

EXTENSIVE INSTRUCTIONS AND DOCUMENTATION
Along with the informative J.I.C. wiring diagram, which includes a sequence of operations and a ladder diagram (for easy troubleshooting), there is an extensively detailed instruction book with a general dimension and assembly drawing, start up, installation, operation, maintenance and troubleshooting information.

WORLDWIDE SERVICE
Although these furnaces are designed for easy in-house start up and maintenance, worldwide factory service and start up assistance is available.

OPTIONS

  • CONTROL, RECORDER AND ELECTRICAL OPTIONS
  • VERTICAL DOORS: Counterbalanced with hand crank, electric gear drive or pneumatic operator.
  • SCR POWER CONTROLS: Single and multi-zone with biasing.
  • NEMA 12 CONTROL PANEL: With fused disconnect switch.
  • SPECIAL HEARTHS: Silicon Carbide and alloy, baskets, racks, roller hearths, special loading devices.
  • VIEWING PORTS
  • VENTS AND VENTURIS: Manual or pneumatic dampers, 300 and 600 CFM venturis for fast cooling.
  • FANS: Various fans for temperatures up to 2200oF for high uniformity and atmosphere distribution.
  • ATMOSPHERE CONTROL: Case is sealed for inert or combustible atmospheres. One option is nitrogen spiked with propane for high decarburization resistance. Alloy retorts for low dew point operation. Atmosphere control systems with safety systems to meet NFPA 86C.

SPECIFICATIONS

MODEL NUMBER ACTUAL INSIDE DIMEN UNIFORM WORK DIMEN HEARTH DIMEN EXTERNAL DIMEN OPT VERT DOOR STAND HIGH STAND LOAD WGHT APPRX SHIP WGHT
  W H D W H D W D W H D HGHT K.W. K.W. (LBS) (LBS)
XLE 524 16 18 25 13 13 20 13 22 54 59 48 99 13.5 18.0 175 1600
XLE 814 19 15 25 16 10 20 16 22 57 56 48 93 14.0 18.0 200 1700
XLE 816 19 15 37 16 10 32 16 32 57 56 60 93 19.0 25.0 300 1900
XLE 824 19 21 25 16 16 20 16 22 57 62 48 105 17.0 22.0 200 1800
XLE 836 19 21 37 16 16 32 16 32 57 62 60 105 22.5 29.0 300 2100
XLE 848 19 21 49 16 16 44 16 33 63 62 60 105 27.0 35.0 450 2200
XLE 244 25 27 25 22 22 20 22 22 63 68 48 117 27.0 35.0 300 2100
XLE 246 25 27 37 22 22 32 22 33 63 68 60 117 31.5 42.0 450 2400
XLE 248 25 27 49 22 22 44 22 44 63 68 72 117 38.0 49.5 600 2800
XLE 272 25 27 73 22 22 68 22 66 63 68 96 117 51.0 68.0 900 3500
XLE 448 25 51 25 22 46 20 22 22 63 93 48 N/A 38.0 49.4 300 2900
XLE 3248 31 27 49 28 22 44 28 44 69 68 72 117 48.0 64.0 700 3100
XLE 3260 31 27 61 28 22 56 28 56 69 68 84 117 55.0 71.5 850 3500
XLE 3272 31 27 73 28 22 68 28 66 69 68 96 117 59.0 78.5 1000 3900
XLE 3348 31 33 49 28 28 44 28 44 69 74 72 129 48.5 65.0 700 3400
XLE 3360 31 33 61 28 28 56 28 56 69 74 84 129 60.0 78.0 850 3800
XLE 3372 31 33 73 28 28 68 28 66 69 74 96 129 66.5 88.5 1000 4200
XLE 3436 37 27 37 34 22 32 32 32 75 68 60 117 40.0 52.0 600 2900
XLE 3448 37 27 49 34 22 44 32 44 75 68 72 117 48.0 64.0 900 3400
XLE 3472 37 27 73 34 22 68 32 66 75 68 96 117 66.0 88.0 1200 4200
XLE 3636 37 39 37 34 34 32 32 32 75 80 60 141 51.0 61.3 600 3300
XLE 3648 37 39 49 34 34 44 32 44 75 80 72 141 56.0 66.5 900 3900
XLE 3672 37 39 73 34 34 68 32 66 75 80 96 141 82.0 109.0 1200 4800
XLE 4060 42 39 61 39 34 56 36 56 79 80 84 141 70.0 91.0 1000 4600
XLE 4080 42 39 81 39 34 76 36 76 79 80 104 141 96.0 125.0 1500 5400
Dimensions are in inches. External dimensions include typical control panel mounted on right side. Specify voltage. 480 volts is standard; 208, 240, 380 and 575 volts are optional. 3 phase is standard; single phase is available. 60 or 50 Hertz. Heat Loss is total K.W. lost per hour at 1800F/968C. Heat Storage is the total K.W. it takes to heat furnace up to 1800F/968C. Multiply K.W. by 3412 to get BTUs. Heavier loading weights are optional. Tighter uniformity can be achieved by using a smaller portion of the work space. Specifications are subject to change without notice.

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RED CORONA 
PHONE: 02-2027-1377
FAX: 02-2027-1379
#504 Starvalley, Ka san, Keum Cheon, Seoul, S.Korea
General Information: redcorona@redcorona.co.kr