Product Structure

Enclosed Tunnel Shell

Material: Corrosion-resistant materials such as fiberglass reinforced plastic (FRP), polypropylene (PP), and stainless steel (316L). FRP is most commonly used due to its lightweight, high strength, and seamless integral molding characteristics.
Structure: Modular design in sections for easy transportation and installation. Equipped with observation windows, quick-opening maintenance doors, and emergency exhaust vents.
Sealing: All interfaces and door seams use corrosion-resistant rubber sealing strips to ensure airtightness. Flexible air curtains (plastic strip curtains) or enclosed airlock chambers are installed at the workpiece entry and exit points to minimize gas leakage.

Internal Process Sections

Pickling Section: Equipped with acid-resistant circulation pumps and nozzles (spray type) or used as an immersion tank. The tank is integrated with the tunnel or built-in.
Multi-stage Rinsing Section: Typically 3-5 stages of counter-current spraying, with deionized water commonly used in the last stage.
Drying Section: Built-in hot air circulation fan and high-efficiency filter to dry the workpieces.
Material Handling System: Roller conveyors, chains, or overhead conveyors running through the tunnel, made of acid-resistant alloy or coated with rubber.

Negative Pressure Ventilation and Exhaust Gas Treatment System (Key Component):

Ventilation ports are installed at both ends or critical sections of the tunnel. Fans maintain a slight negative pressure inside the tunnel (-50 to -100 Pa), ensuring that any leaks are drawn inward rather than escaping outward.
The centrally collected exhaust gas is sent to a high-efficiency acid mist purification system (such as a two-stage packed bed scrubber + demister).

Circulation and Fluid Replenishment System:

Each process tank has an independent circulation, filtration, and heating/cooling system.
Equipped with automatic acid addition, water replenishment, and water quality monitoring devices.

Intelligent Control System:

PLC/DCS Control: Integrates the control of all motors, valves, pumps, heaters, fans, and sensors.
Safety Interlocks: Automatically shuts off the pickling pump and reduces ventilation when the tunnel door is opened.
Environmental Monitoring: Acid mist concentration alarms are installed outside the tunnel and in the workshop for double protection.

Application Areas

High-end strip/wire pickling

Continuous pickling lines for stainless steel, silicon steel, and special alloy steels.

Precision parts pickling

Automotive, aerospace, and medical device parts requiring extremely high cleanliness and process consistency.

Non-ferrous metal pickling

Pickling or polishing of copper, aluminum, titanium, and their alloys. Pre-treatment lines for electroplating and anodizing.

If you have any questions or needs, please contact us, we will wholeheartedly provide you with professional technical advice and services!