Pit Furnace

These furnaces are used for a variety of heat treating applications including those requiring inert atmospheres where overhead handling equipment is used.

Full opening door exposes entire work space for easy loading. Precision microprocessor based temperature controls and energy-saving insulation maximize the cost efficiency and performance of these rugged units. Ideal for severe service applications – load capacities to 1200 lbs.

Outside Dimensions

• All Models: Control panel overhang 9″ right side

Gas Models:

• Outside depth increases by 10″
• Combustion blower overhang 36″ rear

Operating Characteristics

• Accuracy as percent of controller span
• Uniformity at 100°F below maximum temperature
• Rise Time in minutes to 100°F below maximum temperature
• Tests run with empty oven and minimum exhaust
• Performance will vary with load and application

Certifications

• UL Listed Control Panel
• Meets the Requirements of the Following Standards:
• NFPA 86 (Standard for Ovens and Furnaces)
• NFPA 70 (National Electric Code)
• FM (Factory Mutual)
• OSHA

Caution

• When processing combustible material fire protection should be considered
• Not for use with flammable solvents or vapors. Other models available for these applications

Safety Equipment

• Adjustable manual reset excess temperature interlock to turn off heat on malfunction of main temperature controller

Electric Heat Includes

• Separate heating element control contactors to turn off heat on malfunction of main control contactors
• Door interlock turns off power to heating elements when door is opened to protect operator from line voltage at heating elements

Gas Heat Includes

• Multiple modulating burners fired under hearth from opposing sides to circulate heated air
• Automatic pre-ignition purge period to clear accumulated gas or fumes from furnace
• Push button electric ignition
• Microprocessor based electronic flame safeguard protection for each burner to continuously monitor flame and close gas valves if flame is not present
• Combustion air blower
• Combustion Blower air flow safety switch to close gas valves on loss of combustion air flow
• High and Low gas pressure switches to confirm safe operating pressure range
• Two pilot valves for each pilot to guarantee gas flow to pilot can be stopped
• Two main safety shut off valves for each burner with valve seat position indicator to assure gas flow to each main burner can be stopped
• Proof of closure switch on one main valve at each burner to prevent igniting pilot unless main valve is closed
• Leak test station at each pilot and main burner valve to allow testing for leakage through valve
• Door interlock drives main burners to low fire as door is opened to protect operator from flames

Controls

• Digital temperature controller
• LED pilot lights
• On-off heat switch
• 5 kA short circuit current rating (SCCR)

Construction

• Choice of

* Air or Inert Atmosphere construction

* Electric or Gas heat (Air construction only)

* 208 volt, 230 volt or 460 volt, 3-phase, 60 HZ – other input power available

• All welded construction
• High temperature Kanthal A-1 coiled wire heating elements supported in vacuum cast refractory ceramic fiber located on all side walls
• 1000 BTU per cubic foot natural gas at 2 psig pressure – propane available. Inlet 1” NPT up to 800,000 BTU/hr, 1-¼ “ NPT to 1,000,000 BTU/hr, 1-½” NPT above 1,000,000 BTU/hr
• Insulated with 9”of light weight, energy saving refractory ceramic fiber
• Load supporting floor insulated with 2” of 18-½ lbs per cubic foot density 1900⁰F block and 4” of insulating refractory
• 3/16” steel plate reinforced furnace shell with Trilite Green enamel finish
• ½” thick steel top plate
• Fire brick throat to protect furnace during loading
• Brushed stainless steel control panel face
• Powered door supported by structural steel arms, hinged at rear with heavy duty shaft and pillow block bearings
• Electric door: Electromechanical operator and lever arm rotate door shaft
• Air door: Air cylinder connected to heavy duty sprockets and roller chain rotate door shaft
• Soft insulation on door hot face seals against throat brick and steel front plate
• Fully assembled and factory tested