Pit Furnaces

Bulletin PH-770

11000℃
HEAVY DUTY
ELECTRIC AND GAS HEAT TREATING

SAKAV standard 11000C pit 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 workspace for easy loading. Precision microprocessor based temperature controls and energy-saving insulation maximize the cost efficiency and performance of these rugged units. Nine standard models from 3 to 45 cubic feet built for long, hard, continuous use

STANDARD FEATURES

Controls

- Digital, microprocessor based, thermocouple actuated, indicating temperature controller.
- Modulating burner on gas furnaces.
- Motor control push buttons and on-off heat switch.
- Easy-to-see pilot light.

Safety Equipment - Electric Furnace

- Adjustable, thermocouple actuated, manual reset excess temperature controller excess temperature controller.
- Separate heating element control contactors.
- Door interlock switch turns off power to heating elements when door is opened; restores power when door is closed.

Safety Equipment - Gas Furnace

Adjustable, thermocouple actuated, manual reset excess temperature controller.
Electronic flame safeguard protection.
Combustion air blower with air flow safety switch.
Purge timer.
High and low gas pressure switches.
Latch-type manual reset main gas valve.
Testing device to test tight closure of main gas valve.
Solenoid blocking valve up to 400,000 BTU/HR heat input; motorized backup valve and vent valve over 400,000 BTU/HR

Construction

3/16" steel plate reinforced furnace shell
1/2" thick steel front plate
Brushed stainless steel control panel face
Powered vertical lift door
Door hot side faces away from operator at all times.
Heavy duty ceramic hearth plates supported by firebrick piers.
1 year limited warranty

Every furnace fully assembled and individually factory tested.

Specifications

Specifications will be changed without prior notice

STANDARD EQUIPMENT

All Models

- 230 volts, 3-phase,50Hz
- Other electrical characteristics available Wall insulation, 7" thick, consisting of:
- 5" of 12500C, 8 lbs./cf. ceramic fiber blanket.
- 2" of 9250C, 4 lbs./cf. ceramic fiber blanket. Roof insulation 8" thick consisting of :
- 4" of 12500C insulating castable.
- 2" of 10500C, 18 ½ lbs/cf block insulation

Furnace shell is made of 3/16" thick steel plate reinforced with structural steel plate reinforced with structural steel. Powered door supported at rear by heavy duty shaft and pillow block bearings, Open door exposes entire workspace for easy loading. Floating door construction provides excellent heat seal by pressing soft insulation against 1/2" thick steel top plate. Exterior painted with Trilite Green enamel.
Each features completely wired, side access control panel assembled on the furnace enclosing terminals for incoming power, temperature controllers push buttons and pilot lights.

ELECTRIC MODELS

Safety devices as listed on the front of this bulletin. Heating element contractors electrically interlocked with door opens and restore power when closed. High temperature alloy wire heating elements supported in vacuum cast ceramic fiber. Heating elements located at four sidewalls.

Gas Models

- 1,000 BTU natural gas at 2 psig at 2 psig pressure;
1" NPT inlet up to 800,000 BTU/HR
1 ¼" NPT 850,000 to 1,000,000 BTU/HR
- Other gas characteristics available

Safety devices as listed on the front of this bulletin. Automatic preignition purge period and push button electric ignition contributes to ease of operation. Modulating gas burners fire from opposing sides to circulate heated air through the workspace. Gas burners protected with electronic flame safety relay. Door interlock switch drives main burners to low fire when door is opened and restores control when door is closed.

ELECTRIC DOOR

Door pivots upward above furnace, clearing top opening for easy loading. In the closed position, full door weight seats door firmly against furnace top plate. Structural steel pivot arms supported on furnace top plate by rugged pillow blocks are connected to a heavy-duty electromechanical actuator. The door is controlled by a switch at the furnace control panel.

AIR DOOR

Door pivots upward above furnace, clearing top opening for easy loading. In the closed position, full door weight seats door firmly against furnace top plate. Structural steel pivot arms supported on furnace top plate by rugged pillow blocks are connected to a large diameter air cylinder. The door is controlled by a manual air valve with supply filter, lubricator and regulator.

ADDITIONAL EQUIPMENT AVAILABLE

• Programmable Temperature Controller, microprocessor based, digital indicating, thermocouple actuated, in lieu of standard controller.........................................................PTC3
• Recording Thermometer, thermocouple actuated, 24-hour, 10" diameter circular chart used in conjunction with standard controller.............RT
• Programmable Recording Temperature Controller, microprocessor based, thermocouple actuated, digital display, 24-hour, 10" diameter circular chart, in lieu of standard controller ....................PRTC3
• Digital Timing System, incorporated into standard temperature controller, 99 hour 59 minute range, starts timing at temperature set point and shuts down furnace at end of set time .........................DTS3
• Shut Down Timer, with continuous "hold" feature 1,5, 10 or 30 hour range.............SDT
• Batch Timer, for uniformly timing batch operations. Continuous alarm with door interlock; alarms at end of preset time period until door is opened or timer reset. 1,5,10 or 30 hour range........................ BT
• Inert Atmosphere Construction, available on electric furnaces only, includes continuously welded furnace shell, inert atmosphere gas inlet and outlet, sealed terminal boxes, high temperature door gasket....IAC
• Inert Atmosphere Inlet Piping, complete with indicating flow control and gas valve. Specify atmosphere...IA

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