High Temperature Electric Batch Ovens for Zinc Oxide Powder Processing

The equipment was developed for a zinc oxide powder processing application associated with pharmaceutical and cosmetic material production. The oven platform had to provide a repeatable, high-temperature batch capability that could be duplicated across multiple installed units while supporting export deployment and customer operating practices.

APPLICATION REQUIREMENT

• The equipment had to process zinc oxide powder in a controlled batch format.
• The oven platform supports material processing associated with pharmaceutical and cosmetic production.
• The customer required a repeatable platform suitable for ongoing multi-unit deployment rather than a one-off experimental system.
• This order continued an established repeat program, with this batch representing the most recent supply group delivered.

WORK CHAMBER / LOAD REQUIREMENT

• Required internal work chamber: 60 in W × 60 in D × 96 in H.
• The oven had to support a cart-loaded batch process. Maximum product load basis: approximately 3,615 lb per batch.
• The loading concept was based around a steel product cart configured for multiple tray levels.
• The cart basis accommodates tray positions sized around a 48 in × 48 in × 2.5 in tray envelope.

MATERIAL HANDLING / OPERATOR REQUIREMENT

• The oven had to load and unload from one end through bi-parting swing doors.
• After the cycle is complete, the operator opens the doors and removes the cart from the oven.
• The process required an insulated floor and guided loading path suited to repeated cart movement.

PROCESS REQUIREMENT

• The system had to support repeatable high-temperature batch heat treatment of powder-based product loads.
• The customer required a robust, production-oriented oven platform rather than a light-duty lab unit.
• The process basis required clean, durable internal materials suited to repeated powder-processing service.

SAFETY / COMPLIANCE REQUIREMENT

• The oven was required to be designed on an NFPA 86 Class B basis.
• The documented process basis was no VOCs allowable.
• The equipment required appropriate excess-temperature protection, airflow proving, and controlled heater shutdown logic for safe operation.

UTILITY / SITE REQUIREMENT

• Required electrical service: 415V / 3PH / 50Hz.
• Full-load current basis: approximately 261.1 A FLA.
• The export installation required controls and wiring architecture adapted for the destination site requirements.

SERVICE / SUPPORT REQUIREMENT

• Because the equipment was being installed at a remote location, the project incorporated a controls architecture that supported remote diagnostics and off-site troubleshooting visibility.
• The system needed to support practical remote review of operating conditions without requiring immediate on-site factory presence for every issue.

PROGRAM / DELIVERY REQUIREMENT

• This project formed part of a repeat-unit supply relationship, with six total ovens ultimately delivered.
• The ovens were factory assembled, pre-wired, tested, and prepared for export shipment.

These thermal process requirements were established from the need to process zinc oxide powder in a repeatable, high-temperature electric batch oven platform.

TEMPERATURE CAPABILITY

• Operating range: 662°F to 932°F (350°C to 500°C).
• Maximum operating temperature: 932°F (500°C).
• Required work-area temperature uniformity: ±10.8°F (±6°C).

PROCESS BASIS

• The thermal process basis is high-temperature batch heat treatment of zinc oxide powder.
• The ovens support production-oriented material processing associated with pharmaceutical and cosmetic applications.
• The thermal platform had to be repeatable across multiple installed ovens serving the same customer program.

HEAT INPUT REQUIREMENT

• Heat source: electric resistance heating. Heater basis: 3 kW elements.
• Installed heat basis: nominal 180 kW total.
• Documented wiring basis: six heater banks at 29.4 kW per bank, for 176.4 kW total operating basis.

AIRFLOW DELIVERY REQUIREMENTS

• Required airflow style: full horizontal airflow.
• Recirculation airflow basis: 8,000 CFM. Recirculation static pressure basis: 2.5 in. w.c.
• Air movement had to support even heat transfer across a tray-loaded cart arrangement.

EXHAUST / VENTILATION BASIS

• Exhaust airflow basis: 255 CFM.
• Exhaust fan basis: PQ65 exhauster delivering 255 CFM at 1 in. w.c.
• Documented process basis: no VOCs allowable. Oven classification basis: NFPA 86 Class B.

THERMAL INSTRUMENTATION / CONTROL BASIS

• Primary temperature controller: WATLOW F4T ramp/soak controller. Thermocouple type: Type J.
• Work-area excess-temperature protection: independent high-limit controller.
• Work-area-to-atmosphere pressure monitoring included for process and operating visibility.
• Heater-bank current monitoring included across all heater circuits.

SAFETY / OPERATING BASIS

• The oven was designed so heat is removed if required safe-operating conditions are not met.
• The thermal system includes airflow proving for both recirculation and exhaust functions.
• The operating sequence includes controlled shutdown logic to protect the oven during cool-down.

To deliver the customer and thermal process requirements, the following equipment concept and architecture was developed for this zinc oxide powder processing application.

OVERALL CONCEPT

• Three identical high-temperature electric batch ovens supplied as a repeat-order group.
• Designed for zinc oxide powder processing associated with pharmaceutical and cosmetic material production.
• Developed as part of a broader multi-unit platform already proven with the customer.
• The design uses a back-mounted heat chamber and one-end cart loading.

HEATING ARCHITECTURE

• Heat source: electric resistance elements. Installed heater basis: 3 kW elements providing nominal 180 kW total.
• Heater control arranged in six independently wired heater banks.
• Backup contactors and solid-state relay control are used across the heater-bank architecture.

AIRFLOW / RECIRCULATION ARCHITECTURE

• Airflow pattern: full horizontal airflow.
• Recirculation fan: New York Blower 208 PLR plug fan — 8,000 CFM at 2.5 in. w.c.; 7.5 HP motor; VFD-controlled speed.
• Exhaust fan: PQ65 exhauster — 255 CFM at 1 in. w.c.; 1 HP motor.
• Supply ductwork: four-sided, straight duct construction with adjustable discharge louvers for balancing and uniformity tuning.
• Return ductwork fabricated to complement the supply pattern and provide additional control of work-area airflow behavior.

CHAMBER / CONSTRUCTION ARCHITECTURE

• Internal work chamber: 60 in W × 60 in D × 96 in H. Interior volume: 200 ft³ (5.66 m³).
• Wall system thickness: 8 inches. Insulation: 2 in of 8 lb Superwool (hot-face) backed by 6 in of 6 lb mineral wool.
• Interior wall material: 18 gauge 304 stainless steel. Exterior wall material: 3/16 in mild steel. Exterior finish: PQ Blue.
• The oven includes a 3-inch insulated floor designed to be bolted to the concrete foundation.

DOOR / ACCESS ARCHITECTURE

• Door style: 8-inch-thick bi-parting swing doors on one end.
• Door construction: triple-wall reinforced doors with structural reinforcement for hinges and hardware.
• Interior door surface: 304 stainless steel. Exterior door surface: mild steel.

LOAD-HANDLING ARCHITECTURE

• Product handling concept: steel product cart with 17 shelf positions at 5-inch vertical centers.
• Tray envelope basis: 48 in × 48 in × 2.5 in.
• The cart design incorporates a two-piece reinforced concept with support-angle orientation intended to improve airflow around the load.

CONTROLS ARCHITECTURE

• Operator temperature control: WATLOW F4T ramp/soak controller.
• Work-area overtemperature protection: Chromalox 6050 excess-temperature controller.
• PLC platform: Allen-Bradley Micro820. Recirculation fan drive: Allen-Bradley PowerFlex 525 VFD.
• Remote diagnostics: TOSIBOX Lock 150, supported by an unmanaged 5-port Ethernet switch connecting PLC, VFD, controller, and remote access device.
• Additional instrumentation: Type J thermocouples; exhaust and recirculation airflow switches; work-area pressure transmitter; current transducers on all six heater banks; 3-tier stack light and audible alarm.
• Control enclosures: Enclosure 1 — NEMA 1, 40 in × 30 in × 12 in (front of oven). Enclosure 2 — NEMA 1, 47 in × 56 in × 12 in (rear of oven).

SHIPPING / INSTALLATION ARCHITECTURE

• The ovens were pre-assembled, pre-wired, and pre-tested prior to shipment.
• Each unit underwent fit-and-finish review and multi-point uniformity testing before release.
• The platform was developed for export deployment as part of an established repeat-order program.