About Industrial Metal Detectors

Industrial metal detectors help remove metal particles and prevent contamination of a product line. This is especially important if the products are consumed by people or animals. Industrial detectors help ensure product safety by alerting the presence of unwanted metal (sometimes referred to as "tramp metal") in products. They also can help identify faulty equipment in other production stages. Tramp metal from broken or damaged processing equipment is one source of contamination.

Purpose

The food and beverage, textile, plastics and pharmaceutical industries use industrial metal detectors as part of their quality control processes. A key safety issue in the food and beverage industry, for example, is contamination of food by tramp metal from machinery used in the production process. Traditionally, industries use metal detectors at the output stage of production to ensure that no contaminated products are released. However, some manufacturers of industrial metal detectors advise their customers to use these devices at the input stage as well. Doing so can detect tramp metal early in the production process and help reduce product waste by preventing contamination of an entire batch. While finding unwanted metal particles, industrial metal detectors can also ensure that desired metal elements are present. Toys found in breakfast cereal boxes are one example of a desired metal element in a product.

Components

The basic components of industrial metal detectors include the sensor, signal processor, output device and the control. The sensor is what reacts to the proximity of metal particles. When it detects that metal is present in the product being screened, the sensor sends a signal to the filter. The filter, or signal processor, is an internal computer. When the sensor detects that metal is present, the filter activates a signal--usually an alarm tone--from the output device. The metal detector's control governs the operation of all other components.

Specialized Uses

The most advanced industrial metal detectors have record-keeping capacities that allow them to store records of all metal detections. Operators can access these records--which include details on the products screened, the type of contaminant and the detection time. The latter is important for operators to locate other product that may be contaminated, or identify any points in the production process at which contamination may have occurred.

Caution

A key to successful operation of industrial metal detectors is to establish and respect a metal-free zone around the device. The region surrounding the device should be kept clear of metal elements so that the detector can reliably detect "tramp metal" in products.

Types

Industrial metal detectors come in many shapes, sizes and styles. Two of the most common include the horizontal aperture and vertical aperture models. The former allows products to enter the opening (or aperture) via conveyor belt. The vertical aperture is intended for use in settings where products to be inspected are transported by pneumatic means.