Electric Class A Cabinet Oven for Drying Water Slurries of Glass and Inorganic Powders

The project required a batch drying oven sized for controlled thermal processing of water slurries of glass and inorganic powders within a specialty materials manufacturing environment. The customer needed a compact cabinet platform that could support repeatable drying while accommodating variable product arrangements and maintaining safe operation.

APPLICATION REQUIREMENT

• The system had to support batch drying of water-based slurry materials associated with glass and inorganic powder processing.
• The process required a controlled heated environment suitable for removing moisture from production loads without sacrificing repeatability.
• The customer required a cabinet-style batch oven rather than a larger walk-in format.

WORK CHAMBER / LOADING REQUIREMENT

• Required work chamber: 55 in W × 30 in D × 60 in H.
• The oven had to support cart-based loading for flexible batch handling.
• The delivered cart had to support mixed shelf capacities for different product weights and loading arrangements.
• The final cart package provided 1000 lb total cart capacity with two 100 lb shelves and two 250 lb shelves.

OPERATOR / ACCESS REQUIREMENT

• The oven had to allow front loading and unloading through two swing doors.
• The floor and guide-track arrangement had to support repeatable cart positioning through the chamber.
• Product and fixture placement had to be arranged to minimize restriction of airflow through the load.

QUALITY / CONTROL REQUIREMENT

• The customer required repeatable thermal drying performance at the defined process temperature.
• The oven had to maintain the stated work-zone temperature uniformity.
• The process required operator control over fan operation, purge completion, and heat enable.

SAFETY / FACILITY REQUIREMENT

• The delivered equipment had to use Class A exhaust and purge safety architecture.
• The oven had to include airflow proving and excess-temperature protection before heat could operate.
• The project required compatibility with 230V / 3PH / 60Hz plant power.
• GA front elevation
• Cart arrangement drawing

The project required a controlled forced-convection drying process based on horizontal airflow, electric heat input, moisture removal, and interlocked exhaust sequencing.

TEMPERATURE REQUIREMENT

• Operating temperature basis: 302°F.
• Maximum temperature basis: 350°F.
• Required work-zone uniformity: ±10°F.

DRYING REQUIREMENT

• The process required removal of moisture from water slurry loads containing glass and inorganic powders.
• The thermal process depended on repeatable circulation of heated air across the load to support consistent drying from batch to batch.

AIRFLOW / HEAT-TRANSFER REQUIREMENT

• Airflow direction basis: full horizontal airflow.
• The process required forced-convection heat transfer across the chamber.
• Based on the documented recirculation airflow and the chamber cross-sectional area in the airflow direction, chamber air velocity was approximately 96 feet per minute.

HEAT-INPUT REQUIREMENT

• Heat source: electric resistance heat.
• Installed heating capacity: 24 kW total.
• The heat system was divided into two independently switched 12 kW heater banks.

VENTILATION / SAFETY REQUIREMENT

• The thermal process required a powered exhaust system operating ahead of heat enable.
• The delivered exhaust basis was 225 CFM.
• The oven used Class A purge and airflow-proving logic before the heater banks could operate.
• The maximum documented volatile-load basis was 0.21 gal per batch.

COOLDOWN REQUIREMENT

• The process required continued fan operation during cooldown.
• The operating basis required that fans remain on until oven temperature dropped below 250°F.
• GA airflow view
• Wiring diagram sequence / safety logic area

To satisfy those requirements, Precision Quincy configured the project as a 43D-350 electric Class A cabinet oven with horizontal airflow, electric heater banks, powered exhaust, cart loading, and interlocked controls.

OVERALL CONCEPT

• One electric Class A cabinet oven.
• Compact front-loading batch configuration.
• Cart-loaded work chamber sized for variable batch drying.

HEATING ARCHITECTURE

• Heat source: electric resistance heat.
• Total installed heat: 24 kW.
• Heating split into two 12 kW heater banks.
• Each heater bank built from twelve 1000 W heating elements.
• Heater power controlled through solid-state relays with backup contactors.

AIRFLOW ARCHITECTURE

• Airflow pattern: full horizontal airflow.
• Recirculation system based on a Jan-Air radial blade assembly delivering 1200 CFM at 2 in. W.c.
• Recirculation fan motor: 1.5 HP.

EXHAUST / VENTILATION ARCHITECTURE

• Exhaust system based on a PQ1 exhauster delivering 225 CFM at 1 in. W.c.
• Exhaust fan motor: 0.75 HP.
• The oven included a fresh-air damper, purge timer, and airflow switches interlocked with the heating system.

CHAMBER / SHELL ARCHITECTURE

• Internal work chamber: 55 in W × 30 in D × 60 in H.
• 2-inch-thick wall construction with 2 inches of 6 lb mineral wool insulation.
• Interior material: aluminized steel.
• Exterior finish: PQ blue.
• Control enclosure finish: ANSI 61 gray.
• The oven floor included cart guide tracks for repeatable cart positioning.

LOADING ARCHITECTURE

• Two swing doors for front access.
• Shelf cart with 1000 lb total capacity.
• Cart construction in unpainted mild steel with aluminized shelves.
• Shelf package included two 100 lb shelves and two 250 lb shelves.

CONTROLS ARCHITECTURE

• Primary temperature controller: SSI 804.
• Work-area excess-temperature controller: Gefran 650L.
• Control enclosure: 42 in × 36 in × 12 in NEMA 1 enclosure.
• Operator interface included separate controls for exhaust fan, recirculation fan, and heater banks 1 and 2.
• The control package included purge complete, fan on, and heater-bank on indication.
• The enclosure also included an enclosure cooling fan.

SAFETY ARCHITECTURE

• Applicable design basis: NFPA 79, NFPA 86, and UL 508A open industrial control panel construction.
• Safety logic included exhaust airflow proving, recirculation airflow proving, timed purge before heat enable, and excess-temperature shutdown.
• Enclosure layout drawing
• GA overall view
• Cart arrangement drawing