Three-Zone Continuous Curing Oven for High-Volume Trim Finishing

A major North American building-products manufacturer required a continuous curing module to be integrated inline as part of a larger, two-machine production cell (the curing system mechanically and controls-wise interfaces with upstream/downstream equipment).

MATERIAL FLOW & LAYOUT

• Product travels widthwise (boards oriented with length perpendicular to direction of travel; "wide way in").
• Single product path runs through the curing system.
• The customer required a fixed overall equipment length to match their production layout.

THROUGHPUT REQUIREMENT (PRIMARY)

• The key requirement was mass throughput (≈152,000 lb/hr target). Line speed is secondary and is simply whatever speed is required to achieve lb/hr given product mix.

PRODUCT + UPSTREAM CONTEXT

• Trim boards are wood/composite.
• Upstream, the trim is wrapped on the top and bottom surfaces.
• After trim is cut, the exposed edges must be painted; this system's job is to dry/cure the edge paint.

ENERGY FOCUS / EDGE-ONLY HEATING CHALLENGE

• The customer's process requires concentrating heat transfer on the edges without wasting energy heating surfaces that do not need it.
• The system must accommodate a wide product width range (~1.5 in to 12 in) while still directing airflow/heat where needed (edge-focused) without disturbing product.

CONVEYOR / VALVE REQUIREMENT

• The customer required a conveyor approach that supports boards reliably while minimizing the number of chain strands to maximize value.

LOW-NOX BURNER CORPORATE STANDARD

• The customer requires low-NOx burners.
• This creates a control/turndown challenge, especially at low heat-load conditions (e.g., empty/lightly loaded operation) where it is difficult to maintain low temperatures while preserving needed high temperature capability.

ACCESS / MAINTAINABILITY REQUIREMENT

• The customer required side access so operators can quickly remove broken boards inside the oven (open side access rather than full disassembly).

PRODUCT STABILITY REQUIREMENT

• Boards must remain stable and properly guided—no lateral drift, hopping, or airflow-induced movement—while still achieving the required edge paint cure.

FOOTPRINT CONSTRAINT

• The customer provided a very limited installation envelope; the full solution had to fit within 377 inches total length.

These thermal process requirements were jointly developed to meet the customer's process needs, based on a combination of Precision Quincy testing, customer experience, and Precision Quincy's prior experience with similar product lines.

TEMPERATURE REQUIREMENTS

• Normal operating temperature range: 200–300°F.
• Maximum capability: 450°F.

CONVEYOR EXPOSURE / TIME-IN-HEAT

• Conveyor speed must be adjustable to achieve different time-in-heat values based on product size.
• Speed range includes up to 60 ft/min.

EDGE-FOCUSED AIRFLOW DELIVERY

• Airflow must be delivered vertically downward at the board edges.
• Airflow direction is perpendicular to the length of the oven.
• Target nozzle discharge velocity: 5,800 FPM, with allowable variation ±870 FPM.
• Nozzle geometry: 3/8-inch-wide slots.

EXHAUST REQUIREMENTS (TEMPERATURE CONTROL + PROCESS REMOVAL)

• Minimum exhaust: 3,945 CFM total.
• Maximum exhaust capability: 15,750 CFM to support stable low-temperature operation given low-NOx turndown limitations.

HEAT INPUT REQUIREMENT

• Required heat input: 4,800,000 BTU/hr.

MOISTURE LOAD

• Maximum water load capacity: 8 gallons/hr.

TEMPERATURE UNIFORMITY

• ±10°F from setpoint at the nozzle discharge (sufficient to meet even-heating requirement).

To deliver the thermal process requirements (which deliver the customer process requirements), Precision Quincy settled on the following equipment concept and architecture.

OVERALL CONCEPT

• Three-zone, single-path conveyor oven.
• Roof-mounted recirculation fans, burners, and exhaust.
• Conditioned air is directed down from nozzles above the conveyor (edge-focused, vertical-down discharge), then returns down the sides back to the heat source/fan loop.

AIRFLOW/DUCTING ARCHITECTURE ("NAUTILUS" DUCT)

• Each zone uses a Nautilus duct arrangement: recirculation fan shaft transitions from horizontal into a curved down-turn with turning vanes, then back to horizontal distribution.
• Discharge air exits overhead nozzles straight down to the product.
• Return air travels down the sides of each duct path, then flows back up through the burner/heat section, and is re-delivered for heating.

ZONE ARCHITECTURE (ONE FAN + ONE BURNER + ONE EXHAUST PER ZONE)

• Each zone includes: (1) recirculation fan, (1) burner, (1) exhaust connection.
• Recirculation fan: 40-inch fan, 40,000 CFM @ 3 in. w.c. (per fan; 120,000 CFM total), 40 HP motor (per fan; 120 HP total).
• Heating concept: Low-NOx requirement fulfilled using (3) Maxon OvenPak LE15 burners total (one per zone), each 1.6 MMBtu/hr. Emissions control uses a servo-driven system (SmartLink MRV, Maxon/Honeywell) mapped to hold NOx < 30 ppm.

EXHAUST CONCEPT

• Each zone exhaust includes modulating dampers to adjust exhaust rate for cooldown and low-temperature stability given low-NOx turndown limitations.

SERVICEABILITY / ACCESS

• Access is provided via distributed service doors (total of 10 access doors).
• Explosion relief is incorporated in the roof and sidewalls, and also via access door relief as applicable.

SHELL / STRUCTURAL ARCHITECTURE

• Shell is built around a structural steel frame.
• Interior construction uses free-floating sheet-metal pans designed to accommodate thermal expansion/contraction while minimizing through-metal.
• Construction: 16-gauge interior pans (aluminized), insulation outside the interior pans, 16-gauge exterior cladding (mild steel), exterior finished with a two-part epoxy paint, light gray specified by the customer.

SHIPPING ARCHITECTURE

• The oven is designed to ship as three main pieces (three zones), bolted together on site.
• Support feet are integral (not removable for shipment).

CONVEYOR / MECHANICAL CONCEPT HIGHLIGHTS

• Conveyor is an engineered RS60 steel roller chain system with flat sidebar chain.
• Six strands running on replaceable AR500 wear guides.
• Common drive shaft through all six strands to a gearbox; each strand is individually tensioned.
• Take-up/tensioning uses pneumatic tensioners (no rack-and-pinion synchronized take-up).
• Drive concept: 5 HP gearbox-driven conveyor drive, VFD-controlled.

CONTROLS ARCHITECTURE

• Controls are remotely located.
• The system uses an Allen-Bradley CompactLogix PLC integrated with the paired equipment.
• VFDs are Yaskawa (customer-specified).
• Burner safety hardware uses a Karl Dungs-based safety system with Maxon/Honeywell burner control components.

OTHER NOTED ATTRIBUTES

• Roof areas not occupied by explosion relief are outfitted with guard rails for service access.
• Equipment was fully tested and accepted via FAT at Precision Quincy; the customer attended FAT.