Electric Class A Truck Oven for Blade Curing in Aeroderivative Turbine Component Processing

The project was developed to support batch curing of blades in an aeroderivative turbine component environment. The customer needed a thermal-processing platform sized for blade-related work that required controlled curing temperatures, repeatable cycle management, and safe handling of a solvent-bearing Class A process.

APPLICATION REQUIREMENT

• The project required a batch curing oven for blades.
• The oven had to support thermal processing in a facility environment centered on aeroderivative turbine equipment and component work.
• The process required a machine format suitable for repeatable batch loading and unloading, rather than a continuous conveyorized system.

WORK CHAMBER / LOADING REQUIREMENT

• Required work chamber: 48 in W x 48 in D x 60 in H.
• The chamber had to accommodate blade-processing loads while preserving airflow across the work zone.
• Product and fixture positioning had to support clear airflow passage through the oven during operation.

QUALITY / CONTROL REQUIREMENT

• The customer needed repeatable curing performance within the stated work-zone uniformity.
• The process required programmable ramp/soak temperature control for defined thermal cycles.
• The system had to provide stable airflow, controlled heat delivery, and dependable batch-to-batch process repeatability.

SAFETY / ENVIRONMENTAL REQUIREMENT

• The oven had to be configured as an NFPA 86 Class A unit.
• The documented volatile-load basis required powered exhaust and purge logic.
• The process required heat to remain interlocked to proven safe operating conditions.

UTILITY REQUIREMENT

• Required electrical service: 460V / 3PH / 60Hz.
• Design elevation basis: below 1,000 ft.

The project required a controlled curing process built around elevated-temperature forced convection, programmable cycle control, and Class A ventilation.

TEMPERATURE REQUIREMENT

• Operating temperature basis: 600°F to 650°F.
• Maximum temperature capability: 800°F.
• Required work-zone uniformity: ±10°F.

AIRFLOW / HEAT-TRANSFER REQUIREMENT

• Airflow direction basis: full horizontal airflow.
• The process required forced-convection crossflow through the work chamber to deliver repeatable heat transfer across blade loads.
• Using the documented recirculation airflow and the chamber cross-sectional area in the airflow direction, the first-pass average chamber air velocity is approximately 105 FPM.

HEAT-INPUT REQUIREMENT

• Heat source: electric resistance heat.
• Installed heat basis: 54 kW total.
• Heating arrangement basis: two 27 kW heater banks.
• The process required staged heater-bank control to maintain the curing temperature window.

VENTILATION REQUIREMENT

• The process required Class A exhaust and purge sequencing.
• Maximum volatile load basis: 0.32 gal/batch o-xylene.
• Ventilation had to be proven before electric heat could be enabled.

CONTROL / SEQUENCING REQUIREMENT

• Primary control basis: ramp/soak temperature control.
• Minimum purge time basis: 3 minutes.
• Documented operating sequence:
• Start exhaust fan
• Start recirculation fan
• Complete purge
• Turn on heater bank(s)
• Run at temperature or programmed profile

COOLDOWN REQUIREMENT

• The process required continued fan operation during cooldown.
• The system operating basis requires fans to remain on until oven temperature drops below 250°F.

To satisfy those requirements, Precision Quincy configured the project as a 74-800 electric Class A truck oven with horizontal airflow, two-stage electric heat, powered exhaust, integrated floor guides, and interlocked controls.

OVERALL CONCEPT

• One electric Class A truck oven
• Batch-processing format for blade-curing cycles
• Front-loading double-door chamber with guided floor loading arrangement

HEATING ARCHITECTURE

• Heat source: electric resistance heat
• Total installed heat: 54 kW
• Heating split into two 27 kW heater banks
• Heater banks built from eighteen 3 kW elements total
• Heater power controlled through solid-state relays with backup contactors

AIRFLOW ARCHITECTURE

• Airflow pattern: full horizontal airflow
• Recirculation system based on a 13.5 in x 5 in fan assembly delivering 2,100 CFM at 2 in. W.c.
• Airflow package sized to support consistent crossflow through the blade-processing work zone

EXHAUST / VENTILATION ARCHITECTURE

• Class A exhaust based on a PQ1 exhauster delivering 550 CFM at 1 in. W.c.
• Fresh-air damper integrated into the oven body
• Airflow switches and purge timing interlocked with the heating system

CHAMBER / SHELL ARCHITECTURE

• Internal work chamber: 48 in W x 48 in D x 60 in H
• 6-inch insulated wall construction
• Wall insulation: 6 inches of 6 lb mineral wool
• Heat-chamber walls: 5 inches of 6 lb mineral wool plus 1 inch of 8 lb Superwool
• Interior material: unpainted aluminized steel
• Exterior finish: Traffic Grey (RAL 7042)
• Control enclosure finish: ANSI 61 gray
• Floor design includes integrated guide tracks for truck-style loading

DOOR / LOADING ARCHITECTURE

• Two swing doors
• Insulated floor with guided loading path
• Chamber geometry and loading format support stable batch positioning while maintaining airflow access around the load

CONTROLS ARCHITECTURE

• Watlow F4T ramp/soak controller for primary temperature control
• Gefran 650L excess-temperature controller
• Type J thermocouples
• NEMA 1 UL508A open industrial control panel
• Dedicated operator controls for exhaust fan, recirculation fan, and each heat bank
• Panel indication for purge complete, fan on, and heat bank on
• Panel layout includes enclosure cooling and USB access

SAFETY ARCHITECTURE

• Applicable standards basis: NFPA 79, NFPA 86, UL508A
• Safety logic includes:
• Exhaust airflow proving
• Recirculation airflow proving
• Timed purge before heat enable
• Excess-temperature shutdown
• Automatic heat shutdown when required safe operating conditions are not met