Conveyor & Tunnel Metal Detector Systems
Metal Detection Conveyor Systems

Conveyor & Tunnel Metal Detection Systems

Future-Proof Compliance for Inline Packaged and Unpackaged Products

Conveyorized metal detection systems wiithin our range of rectangular tunnel in-line metal detectors are designed to fit your budget and performance needs. These fully automated systems can detect and reject ferrous and non-ferrous metals, as well as hard-to-detect grades of stainless steel. Meet compliance requirements with a single-supplier solution to your food and non-food processing challenges.

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FAQs

How does a conveyorized metal detection system work?

A conveyor is integrated with a tunnel metal detector to allow the product to pass through the aperture of the metal detector and be inspected for metal contaminants.

METTLER TOLEDO Safeline provides a range of industrial tunnel metal detectors to suit your inspection and budget needs. They are capable of detecting all types of metal, including ferrous, non-ferrous, and even difficult to detect grades of stainless steel.

With our wide range of conveyor systems including our latest modular Global Conveyor (GC) Series, an automatic reject device is fitted to the transport system in order to remove any contaminated product from the production line. There are many different reject mechanisms available including:

  • Air blasts
  • Push arms
  • Lift / drop flaps


The type of the reject mechanism installed will depend on the product being inspected. You can also choose from a range of conveyor metal detector belt types, system integration widths & lengths, along with failsafe monitoring features to provide a flexible solution to meet production needs.

The metal detector, transport system, reject device and a suite of integrated sensors work in harmony so metal-contaminated products can be efficiently detected, rejected, and removed from the production process.

Other names you might find which refer to the very same machine are the in-line metal detector, rectangular aperture detector (RAD) and the rectangular tunnel metal detector.

How do I choose the right metal detector conveyor system?

The first step is to choose the right inspection technology for your application. METTLER TOLEDO Safeline offers an extensive range of options, from tuned frequency technology for dry products, to Dual-Simultaneous and Multi-Simultaneous frequency for products that are wet, hot, chilled, cooling or packed in metalized film. Proprietary innovations including Boost mode, eDrive™ and advanced algorithms to increase sensitivity performance and minimize false rejects. Additionally, Enhanced Noise Immunity (ENI) and Enhanced Vibration Immunity (EVI), along with Dynamic Stability Control innovations deliver exceptional reliability in the most challenging production environments.

The design of both a metal detector conveyor and the reject mechanism can also have a major impact on the effectiveness of your overall metal detection program.

A wide range of standard and customized metal detector conveyor systems are available. Each system is tailored to suit specific production needs, from inspecting unpackaged or bulk products to packaged products in a variety of sizes. With METTLER TOLEDO Safeline, customers can also choose from several compact solutions for small spaces. Our new GC Series is a modular conveyor system suitable for a wide range of conveyorized light to heavy product applications. We design and manufacture our systems in-house, so custom systems can also be built to your exact requirements.

What equipment comes with an industrial conveyorized metal detection system?

In addition to the different reject mechanisms available, other important equipment may include:

  • Lockable containers to collect and hold rejected product
  • Full-length covers between the detector and the reject mechanism
  • Failsafe alarms to alert metal detector faults

There are several additional optional failsafe systems to raise the level of due diligence for manufacturers. Our metal detection systems for conveyorized applications can be tailored to suit specific inspection requirements, including but not exclusively:

  • A choice of aperture sizes
  • Reject mechanisms
  • Failsafe system components
  • Conveyor belt materials
  • Connectivity options

Get a quick quote to learn about more options!

Which environments are conveyorized metal detection systems suitable for?

Our conveyor metal detection systems are suitable for almost any environment, whether you are inspecting dry and packaged products or wet, chilled, and frozen products in extreme environments. We can also supply special solutions for inspecting bulk products in hazardous locations, with metal detector heads certified to comply with ATEX / IECEx and HazLoc regulations.

When the working environment gets tough, your inspection systems need to be tougher. METTLER TOLEDO Safeline's conveyorized metal detection systems can be configured with heavy-duty stainless steel detectors rated at IP69K, and integrated with rugged, heavy-duty conveyor frames sealed up to IP69K standard.

Why buy an integrated metal detection solution from a single supplier?

Careful consideration needs to be taken into account when designing a conveyorized metal detection system, particularly around the static build-up on the conveyor frame, which can interfere with the metal detector and create false rejects. A solid system design eliminates static build-up, allowing the detector to run at optimum sensitivity without false rejects.

Purchasing an integrated metal detection solution from METTLER TOLEDO can help you maximize your equipment performance by having a seamlessly integrated metal detection solution across your production line, without compromising on reliability.

With flexible modular solutions such as our GC Series conveyor metal detection systems, food processors and manufacturers can meet compliance needs now and into the future by adapting the metal detection system to suit changing production line requirements.

What is an inline metal detector?

Industrial inline metal detectors are made to safely detect and reject metal contamination on production lines, helping manufacturers to achieve compliance, minimize the risk of product recalls, and reduce production downtime. They can be designed to detect all types of metal, including ferrous, non-ferrous, and difficult-to-detect grades of stainless steel.

METTLER TOLEDO inline metal detection systems are available for a wide range of food, non-food, and pharmaceutical applications. Our proven tunnel metal detector technology delivers excellent sensitivity and stability with optimized electronic and mechanical integration to support compliance.

What is a tunnel metal detector?

A tunnel metal detector inspects raw or processed foods or non-food products for metal contamination. Food processing companies use tunnel metal detectors to comply with food safety standards and retailer codes of practice. When integrated with a conveyor system, all types of metal contaminants can be detected and rejected, preventing metal contaminated products from reaching the end consumer.

What is the best tunnel metal detector?

When it comes to choosing the best metal detection system, it is essential you find one that meets your application and performance needs. First, determine if you want to simply detect and reject metal and meet required sensitivity limits, or if you need to overcome product effect to detect more metal in wet, hot, chilled, cooling, or metallized film applications.

Choosing the right metal detection solution requires careful consideration - you need a metal detector that can meet your current business objectives, and can adapt to meet future requirements.

Click to discover the best metal detection solutions designed to support various production, quality, and operational needs, and get answers to some of the most common questions faced by food producers.

Where can I use a tunnel metal detector?

A tunnel metal detector is a versatile industrial metal detection solution that can be used in a wide variety of product inspection applications. Tunnel metal detectors can be integrated with conveyor systems to inspect raw, processed, or packaged food or non-food products for all types of metal contaminants. A HACCP analysis will establish the most relevant critical control points, indicating the best installation location for the metal detector.

How can we integrate a tunnel metal detector within a food production line?

The easiest way to do this is to buy an integrated metal detection system consisting of a tunnel metal detector and a conveyor system from a single supplier. METTLER TOLEDO Safeline manufactures a wide range of tunnel metal detectors and conveyor systems designed for food and non-food processing applications. Our metal detection systems for conveyorized applications can be tailored to suit specific inspection requirements, including a choice of aperture sizes, reject mechanisms, failsafe system components, conveyor belt materials, connectivity options, and more.

How does a tunnel metal detector work?

The majority of tunnel metal detectors are balanced coil systems. Three coils are wound onto a non-metallic frame and each coil is parallel with the other two. We explain exactly how tunnel metal detectors operate in our Metal Detection Guide. You can read more about this on page 8 of the guide.

How sensitive is a tunnel metal detector?

The sensitivity of a tunnel metal detector can vary depending on the application, the metal detector manufacturer, and the metal detector itself. Sensitivity performance is determined by the diameter of a sphere made from a specific type of metal. The sphere must be reliably detectable when placed in the center of the aperture of a tunnel metal detector. A tunnel metal detector loses sensitivity the larger the aperture size.

Dry products such as confectionery and cereals are relatively easy to inspect. Detectors operating at high and ultra-high tuned frequencies (typically in the region of 800kHz and above) deliver high levels of overall sensitivity and are especially good at detecting stainless-steel type contaminants.

When inspecting wet or conductive products such as fresh meat, poultry, cheese, fish, and metalized film-packed products, the situation is different. The wet product itself creates a 'product effect signal' in the detector – and this signal needs to be canceled out before inspection can begin. Innovative multi-simultaneous frequency technology can be used to overcome product effects, detecting significantly smaller metal contaminants.

How do I choose the right tunnel metal detector?

METTLER TOLEDO Safeline offers wide variety of industrial tunnel metal detectors for use in food and non-food processing applications. These can be used at various stages of the production process, including inspecting raw materials, in-process to protect downstream equipment, or after final packaging to provide peace of mind that there is minimal risk of subsequent contamination.

The proper selection of metal detector heads will depend on the characteristics of the product being inspected. For challenging applications that are subject to product effect where food is hot, wet, chilled, frozen, or packed in metalized film, industrial metal detectors using multi-simultaneous frequency such as the Profile Advantage can greatly reduce false rejection rate. Go for metal detectors with dual-simultaneous frequency such as M34R GC if budget is the top concern.

For dry product inspection, choose metal detectors with high tuned frequency such as the Profile, PowerPhase Pro or M33R GC.

We also offer several other tunnel metal detection solutions for bulk and compact product inspection, as well as combi systems, which are integrated with a dynamic checkweigher to provide multiple product inspection capabilities within a single unit, offering a compact, sustainable footprint.

How to correctly test your industrial metal detector?

There are many and varied industrial metal detector tests (e.g. single pack, three pack consecutive test, five pack memory test, big ball test, etc.) that should be performed and recorded by food producers when supplying to big retailers. Please refer to our How to Correctly Test Your Industrial Metal Detector guide or the How to Meet Retailer Testing Requirements on-demand webinar for more details.

What is product effect?

Foods that have a high moisture and/or salt content (sometimes called "wet" products) can present what is known as "product effect". This can cause unwanted false readings in metal detectors and can lead to costly product waste due to false rejects. Products impacted include fresh meat, poultry, seafood, jams, preserves, dairy, bakery, and ready meals. An effective metal detection system with Dual- or Multi-Simultaneous Frequency (DSF / MSF) technology can remove the influence of product effect.