Natural Gas Heated Walk-In Oven for Industrial Repair and Heat Treat Processing

The equipment was developed for a heavy industrial repair operation requiring the batch heat treatment of repaired metal components before return to service.

APPLICATION REQUIREMENT

• The equipment had to process repaired metal parts used in heavy industrial service, including gear drives, pumps, bearing assemblies, crushers, conveyors, hydraulic systems, shafts, and similar large industrial components.
• The oven supports stress relieving, tempering, preheating, and other repair-related thermal processing occurring after repair or refurbishment and before return to service.
• The equipment had to support repeatable batch processing for large repaired industrial components with varying shapes and mass rather than small packaged product.

WORK CHAMBER / LOAD REQUIREMENT

• Required internal work chamber: 60 in W × 72 in D × 72 in H.
• The oven had to accommodate substantial industrial repair components with varying geometry and mass.

PROCESS REQUIREMENT

• The system had to support batch heat treating and related repair-process thermal cycles.
• The equipment had to provide controlled thermal performance suitable for repaired industrial components requiring repeatable post-repair heat processing.

SAFETY REQUIREMENT

• The oven was required to be designed as an NFPA 86 Class A unit.
• The oven required appropriate exhaust, combustion, and control architecture for safe natural-gas-fired operation.

UTILITY / SITE REQUIREMENT

• Required electrical service: 575V / 3PH / 60Hz. Full load amperage: 7.8 A FLA.
• Required fuel: natural gas. Gas inlet pressure: 2 PSI. Gas flow basis: 660 CFH.
• Design elevation basis: 2,200 ft.

INSTALLATION / SHIPMENT REQUIREMENT

• The oven was built fully assembled and shipped in one piece.

These thermal process requirements were established from the need to heat treat repaired industrial metal components in a controlled, high-temperature batch environment.

TEMPERATURE CAPABILITY

• Operating range: 350°F to 650°F. Maximum operating temperature: 650°F.
• Required workroom temperature uniformity: ±10°F.

PROCESS BASIS 

• The thermal process basis is batch heat treating of repaired industrial metal components, including stress relieving, tempering, preheating, and related repair-related thermal cycles.
• The process occurs after repair or refurbishment and before return to service, requiring repeatable heat processing for large, heavy components with varying geometry and mass.

HEAT INPUT REQUIREMENT

• Heat source: natural gas. Burner: Maxon OvenPak 408.
• Natural gas inlet pressure: 2 PSI. Gas flow basis: 660 CFH. Design elevation basis: 2,200 ft.

AIRFLOW DELIVERY REQUIREMENTS

• Required airflow style: combination horizontal-vertical airflow.
• Recirculation airflow basis: 4,140 CFM at 4 in. w.c.

EXHAUST / VENTILATION BASIS

• Exhaust airflow basis: 430 CFM. Exhaust fan: PQ1 exhauster delivering 430 CFM at 1 in. w.c.; 0.75 HP motor.
• Maximum volatile load basis: 0.1 gallons per batch. Oven classification: NFPA 86 Class A.

THERMAL INSTRUMENTATION / CONTROL BASIS 

• Primary temperature controller: WATLOW F4T ramp/soak controller. Thermocouple type: Type J.

To deliver the customer and thermal process requirements for this industrial repair heat treating application, the following equipment concept and architecture was developed.

OVERALL CONCEPT

• One natural-gas-heated walk-in batch oven designed for general heat treating of repaired industrial metal components, including stress relieving, tempering, preheating, and related repair-related thermal processing.
• The design uses a back-mounted heat chamber. The oven was fully assembled and shipped in one piece.

HEATING ARCHITECTURE

• Heat source: natural gas. Burner: Maxon OvenPak 408.
• Gas inlet pressure: 2 PSI. Gas flow basis: 660 CFH. Design elevation basis: 2,200 ft.

AIRFLOW / RECIRCULATION ARCHITECTURE

• Airflow pattern: combination horizontal-vertical airflow.
• Recirculation fan: New York Blower 15 PLR plug fan—4,140 CFM at 4 in. w.c.; 3 HP motor.
• Exhaust fan: PQ1 exhauster—430 CFM at 1 in. w.c.; 0.75 HP motor.

CHAMBER / CONSTRUCTION ARCHITECTURE

• Internal work chamber: 60 in W × 72 in D × 72 in H.
• Construction style: insulated panel construction with structural steel reinforcement.
• Wall system thickness: 5 in. Insulation: 5-inch, 6 lb density mineral wool.
• Interior material: aluminized steel. Exterior finish: painted RAL 7042.
• Insulated floor with cart guide tracks.

DOOR / ACCESS ARCHITECTURE

• Door style: bi-parting swing doors.
• The insulated floor and door arrangement support loading and unloading of heavy repair components.

CONTROLS ARCHITECTURE

• Primary temperature controller: WATLOW F4T ramp/soak controller. Thermocouple type: Type J.
• Control enclosure: oven-mounted NEMA 1 cabinet, painted ANSI 61 gray. No PLC used.
• The controller-based architecture matched the repeatable batch heat treating duty of the repair environment.

SAFETY / COMPLIANCE ARCHITECTURE

• Oven classification: NFPA 86 Class A. Maximum volatile load basis: 0.1 gallons per batch.
• Exhaust and combustion architecture sized to support the stated volatile load basis.

SHIPPING / INSTALLATION ARCHITECTURE

• The oven was fully assembled and shipped in one piece.