Gravity fall metal detector systems (also known as "freefall metal detectors" or "gravity-fed metal detectors") are suitable for the inspection of any free-flowing powder or granular products, which includes metal detection for the flour and grain industry, metal detection for the sugar industry as well as metal detection for manufacturers that produce milk powder, dried fruits, and peanuts.

Commonly used for metal detection in food processing, gravity fall metal detectors work by having the product flow through the production line, free-falling under gravity through a small metal detector aperture to achieve high sensitivity. If metal is detected, a fully automatic, high-speed reject device diverts the contaminated product and isolates it from the main product flow.

While not exactly the same, throat or VFFS metal detectors are similar to gravity-fall systems in that they inspect free-falling product under gravity, but throat metal detectors do not have an integrated reject system. Instead, they are combined with a multi-head weigher and bagmaker; if contamination is detected, they will either send a signal to the bagmaker to make a double bag over the contaminated product, or simply stop the line so the contamination can be removed from the production line.

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Gravity fall metal detection systems are designed specifically for the inspection of free-falling powders and granular products in non-pressurized applications, incorporating different reject devices according to the application. Y-valve Gravity Fall systems are suitable for the inspection of powders and granular products. It’s quick release and captive reject mechanism simplifies cleaning procedures, which is especially ideal when product changeovers are frequent and when regular cleaning between production batches is required.

Sealtite Gravity Fall systems feature an innovative design to provide a dust-tight seal. This virtually eliminates the escape of uncontaminated products into the reject channel, reducing product waste. Sealtite technology is ideal for inspection of high-value, dusty products in explosive environments and applications where production space is limited.

Open Diverter Gravity Fall systems provide a cost-effective solution for non-dusty products, and can be upgraded to Sealtite standards retrospectively if required. This system is best for non-dusty granular products where production space is limited.

METTLER TOLEDO Safeline is a global manufacturer of industrial metal detection systems designed for a variety of production environments and product applications, such as food and beverages, pharmaceuticals and nutraceuticals, cosmetics and personal care, chemicals and more.

METTLER TOLEDO Safeline's Profile technology allows manufacturers to reduce the frequency of routine metal detector performance monitoring tests through Reduced Test (RT) Mode. RT Mode enables the metal detector to operate at a higher level of sensitivity than required, monitoring the metal detector's performance to a level of certainty where the frequency of routine performance monitoring can be significantly reduced (subject to quarantine periods).

Another important tool called the Automatic Test System (ATS) can boost productivity and worker safety on the production line by eliminating the need to test at height for most routine performance monitoring tests. ATS decreases the time required to conduct performance monitoring tests by >80% (from 3-5 minutes per line, to under 45 seconds per line). ATS is the only method that can consistently confirm worst-case sensitivity performance, delivering enhanced compliance and greater brand protection.

In some cases, depending on the testing protocol undertaken by your business, Reduced Test Mode and ATS can lead to significant uptime advantages, improved overall equipment effectiveness (OEE), and increased cost savings.

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• Reduced Test Mode for Reduced Performance Testing
• Automatic Testing System (ATS) Brochure

Yes, there are metal detection solutions designed for use in dusty or potentially explosive atmospheres. If operating in a potentially explosive environment, METTLER TOLEDO has options available for Gravity Fall and other metal detection systems where compliance with ATEX / IECEx / Hazloc regulations is required.

METTLER TOLEDO Gravity Fall metal detectors can help contribute to safer working practices when it comes to product inspection in food manufacturing and other manufacturing environments.

1. Reduced Test Mode: By reducing the frequency of metal detector testing using new Reduced Test Mode (RT) technology, there is a corresponding reduction in the number of "ladder climbs" required by an operator to conduct the test, whether to drop the sample through the aperture or access the HMI to run test routines. Emulation, another feature available on our Profile metal detectors, allows the metal detector HMI to be controlled from a variety of networked devices such as a tablet or mobile phone. This again reduces the need to work at height if the HMI is installed in an awkward location.
2. Automatic Testing System: Automatic Testing System (ATS) for metal detectors is another option available on our latest range of Gravity Fall systems. Using a device which stays inside the aperture of the metal detector, it provides a controlled and repeatable non-invasive test process. ATS virtually eliminates the need to work at height to conduct most routine performance monitoring tests, and removes the requirement for line operators to reach across installed equipment to drop the test samples through the aperture of the metal detector.
    

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• Automatic Testing System (ATS) Brochure
• 5 Reasons to Invest in the Automatic Test System