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 metal detectors for detecting ferrous and non-ferrous metals, including the difficult to detect grades of stainless steel, designed to suit your specific inspection and budget needs.

Our conveyor systems have an automatic reject device fit to the transport system in order to swiftly and effectively 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 or packaging type being inspected. You can choose from a range of industrial metal detector conveyor belt types, system integration widths & lengths, and 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 products contaminated with metal can be efficiently detected, rejected, and removed from the production process.

Conveyorized tunnel metal detection systems are also known as in-line metal detectors, rectangular aperture detectors (RAD) and rectangular tunnel metal detectors.

The first step is to choose the right metal detection 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 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 the metal detector conveyor belt and the reject mechanism can 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 metal detectors, customers can also choose from several compact solutions for small spaces. Our 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 be built to your exact requirements.

• Choosing the Best Metal Detection System - Infographic

In addition to the different reject mechanisms available, other equipment and accessories 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 industrial metal detector conveyor belt systems 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
  
  

Our conveyorized metal detector systems are suitable for almost any environment, from industrial metal detectors for packaging for inspecting dry and packaged products, to metal detectors to inspect 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.

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.

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 metal 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 ease compliance with required metal detection standards for the food industry now and into the future by adapting the system to suit changing production line requirements.

Inline metal detectors are used by manufacturers to 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.

• Metal detectors for the food industry
• Metal detectors for the pharma industry
• Metal detectors for the cosmetics industry
• Metal detectors for the chemical industry

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

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. 

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.

The easiest way to integrate a tunnel metal detector into your food production line is to select an integrated metal detection system consisting of an industrial tunnel metal detector and a metal detector conveyor belt 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.

The majority of tunnel metal detectors use balanced coil systems. Three coils are wound onto a non-metallic frame, with each coil parallel to the other two. Learn in more detail how tunnel metal detectors operate with our informational PDF Industrial Metal Detection Guide.

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

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 in dry products 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.

• Industrial metal detector for the sugar industry
• Industrial metal detector for the flour and grain industry
• Industrial metal detectors for the seafood industry
• Industrial metal detectors for the dairy industry
• Industrial metal detectors for the agriculture industry

METTLER TOLEDO Safeline offers a wide variety of industrial tunnel metal detectors for food processing 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 metal detector can greatly reduce false rejection rate. Go for metal detectors with dual-simultaneous frequency such as M34R metal detector if budget is the top concern.

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

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.

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.

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.

Learn more about product effect and how to reduce false rejects in our Product Effect eGuide.