Tunnel Style

Conveyor Metal Detector

Q: What is a Tunnel Metal Detector?

A Tunnel Metal Detector inspects products as they pass through a tunnel-shaped coil on a conveyor or chute. It detects ferrous, nonferrous, and stainless steel contaminants in food, plastics, recycling, and industrial materials.

Q: What industries use Tunnel Metal Detectors?

Tunnel Metal Detectors are used in food processing and packaging, plastics manufacturing, recycling facilities, and general industrial production.

Q: What types of materials can Tunnel Metal Detectors inspect?

They inspect packaged and unpackaged food products, frozen meals, baked goods, powders, grains, spices, dairy, meat, snacks, shredded plastics, pellets, granules, resins, and bulk fibers.

Q: How do Tunnel Metal Detectors work?

Products pass through the tunnel coil on a conveyor or chute. If metal is present, the detector sends a signal to the control unit, which can activate an alarm, stop the conveyor, or trigger a rejection device.

Q: What is the difference between one-piece and two-piece tunnel detectors?

One-piece tunnel detectors are designed for hygienic food processing. Two-piece split-coil detectors are used in plastics, recycling, and industrial applications and can be installed around existing conveyors without cutting the belt.

Q: Are Tunnel Metal Detectors suitable for harsh environments?

Yes. Food models can use washdown-ready hygienic stainless steel housings, while industrial models offer corrosion-resistant and dust-resistant construction for demanding environments.

Tunnel metal detectors provide high-sensitivity detection of ferrous, nonferrous, and stainless steel contaminants in conveyed products. One-piece tunnel designs support food applications, while two-piece tunnel designs suit industrial applications. Both options integrate with existing production lines to support product safety, equipment protection, and quality requirements.

Detects:	Ferrous, nonferrous, and stainless steel
Applications	Food processing, packaging, plastics, recycling, and bulk goods

One-Piece Tunnel Style Metal Detectors

Applications
Food processing, packaging, and ingredient handling

Materials Handled
Packaged and unpackaged products, frozen foods, baked goods, bulk powders, grains, spices, dairy, meats, and snacks

Benefits

High-sensitivity detection of ferrous, non-ferrous, and stainless steel contaminants
Hygienic one-piece design for easy cleaning and washdown compatibility
Integrated system with digital signal processing for high-speed accuracy
Supports HACCP, FSMA, FDA, USDA, and GFSI compliance
Seamless integration with pushers, diverters, or air blast reject systems
Low-maintenance operation with durable construction for 24/7 environments

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Two-Piece Tunnel Style Metal Detectors

Applications
Plastics processing, recycling, and general manufacturing

Materials Handled
Shredded plastic, granules, pellets, bulk fiber, and conveyed product on non-metallic belts

Benefits

High-sensitivity detection of ferrous, non-ferrous, and stainless-steel contaminants
Split-coil design enables installation around existing conveyors without cutting the belt
Ideal for retrofitting inspection capabilities.
Compatible with reject systems and integrates easily into automation environments
Corrosion-resistant construction options for washdown or industrial settings
Supports regulatory compliance and quality assurance programs across industries

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Two-piece tunnel metal detector for plastics and recycling conveyors

Tunnel metal detectors inspect packaged and unpackaged products as they move along conveyors or chutes. They detect ferrous, nonferrous, and stainless steel contaminants to help protect equipment, support product quality, and improve consumer safety.

Bunting offers one-piece tunnel designs for hygienic food processing and two-piece split-coil designs for plastics, recycling, and other industrial applications. Both configurations can integrate with new or existing production lines and support reliable operation in demanding environments.

High-Sensitivity Detection
Identifies ferrous, non-ferrous, and stainless steel contaminants in both food and industrial products.

Hygienic or Industrial Designs
One-piece construction for food safety and washdown cleaning; split-coil versions for conveyors in plastics and recycling.

Supports Compliance & Quality Standards
Helps meet HACCP, FSMA, FDA, USDA, GFSI, and industry-specific quality assurance requirements.

Seamless Integration
Works with reject systems such as pushers, diverters, or air-blast units, and connects to plant automation controls.

Retrofit-Friendly Options
Two-piece models install around existing conveyors without cutting belts, making them ideal for upgrades.

Low-Maintenance Operation
Durable construction and advanced electronics minimize service needs, even in harsh environments.

Tunnel Metal Detectors are used in food safety, plastics, recycling, and industrial quality assurance:

Food Processing & Packaging: baked goods, frozen meals, dairy, meats, snacks, powders, grains, spices, and packaged ingredients.
Plastics & Recycling: shredded plastics, pellets, granules, resins, bulk fibers, and recycled materials moving on non-metallic conveyors.
General Manufacturing: bulk conveyed products and raw materials that require contaminant-free inspection.

These systems protect downstream equipment, reduce costly downtime, and help companies meet regulatory compliance and quality assurance standards across multiple industries.

Tunnel Metal Detectors consist of a coil (one-piece or split design) positioned around the conveyor or chute and a separate control unit housed in an enclosure.
As material passes through the tunnel, the coil scans for metal contaminants. If metal is detected, the coil sends a signal to the control unit. The system processes the signal and triggers programmed actions such as stopping the conveyor, sounding an alarm, marking the product, or activating a rejection device.
Designed for continuous inspection, they provide fast and accurate detection in high-throughput food, plastics, recycling, and manufacturing operations.

FAQs

What is a Tunnel Metal Detector?

A Tunnel Metal Detector is a system that inspects products as they pass through a tunnel-shaped coil on a conveyor or chute. It detects ferrous, non-ferrous, and stainless steel contaminants in food, plastics, recycling, and industrial materials to protect equipment and ensure compliance.

What industries use Tunnel Metal Detectors?

Tunnel Metal Detectors are used in food processing and packaging, plastics manufacturing, recycling facilities, and general industrial production. They are essential for meeting food safety regulations, improving product quality, and protecting downstream equipment from tramp metal.

What types of materials can Tunnel Metal Detectors inspect?

They inspect packaged and unpackaged food products, frozen meals, baked goods, powders, grains, spices, dairy, meat, snacks, shredded plastics, pellets, granules, resins, and bulk fibers. Both food-grade and industrial tunnel detectors are available to match the application.

How do Tunnel Metal Detectors work?

Products pass through the tunnel coil while being transported on a conveyor or chute. If a metal contaminant is present, the detector coil generates a signal that is processed by the control unit. The system then activates alarms, stops the conveyor, or triggers a rejection device to remove the contaminated product.

What is the difference between one-piece and two-piece tunnel detectors?

One-piece tunnel detectors are designed for food safety. They feature a hygienic frame for easy cleaning and are compatible with washdown environments.
Two-piece tunnel detectors are split-coil designs used in plastics, recycling, and industrial applications. They can be installed around existing conveyors without cutting the belt, making them ideal for retrofits.

Do Tunnel Metal Detectors meet food safety regulations?

Yes. Food-grade tunnel detectors are designed to help processors comply with HACCP, FSMA, FDA, USDA, and GFSI requirements. They integrate easily with reject systems to ensure contaminated products are removed from the line before reaching consumers.

Can Tunnel Metal Detectors be integrated into existing conveyor systems?

Yes. Tunnel detectors can be installed on new lines or retrofitted into existing conveyors. Two-piece split-coil designs are specifically built for easy integration without requiring belt removal.

Are Tunnel Metal Detectors suitable for harsh environments?

Yes. Food models are built with washdown-ready, hygienic stainless steel housings, while industrial models feature corrosion-resistant and dust-resistant construction, ensuring reliable operation in 24/7 environments such as recycling plants and plastics facilities.