If you are recycling plastic goods or processing virgin materials, making a product free from metal contaminants is a lot more important today than ever. Trends to thinner walls, tinier hot-runner nozzles, and more expensive and sophisticated machinery and tooling mean that even the smallest piece of tramp metal can cause expensive problems.
Processors often do not recognize the importance of Metal Separator. Even virgin material can acquire metal contaminants at various stages of manufacturing and transportation, right up until the second it enters the throat of your own molding or extrusion machine. Contamination can vary from tiny particles worn off by equipment abrasion to entire nuts or bolts loosened by vibrations in processing machines. There’s also the human factor: Inevitably, items like coins, pens, and paper will occasionally belong to the product stream.
For that reason, metal-detection technology can be used throughout the plastics industry to guard processing equipment and also to ensure product purity. Metal detectors keep your product under strict surveillance at all times and stop unnecessary machine downtime and costly maintenance.
When we speak of “metal detectors,” some processors may think first of magnets. They are used effectively prior to the metal detector for capturing ferrous metals. Less familiar to numerous processors are electronic detectors for all sorts of metals. These are generally active devices that actuate a valve or any other device to reject the contaminated material.
What’s more, electronic metal detectors could be monitored remotely from a pc. This capability provides a record of where and how frequently contamination takes place in your plant. Such valuable data will help you compare the purity of different vendors’ resins or diagnose excessive machine wear.
How metal detection works – There are 2 basic varieties of metal detectors:
Single-coil systems – Whenever a metallic particle falls from the high-frequency electromagnetic field, an eddy current is induced inside the particle, thereby removing energy through the coil system. Because of this the highest amplitude in the coil’s vibration decreases. More energy will then be supplied to increase the amplitude back to maximum level. This disturbance in the coil’s vibration is detected from the electronic circuit as signaling the existence of a metallic particle.
Balanced-coil system – Single-coil systems provide cost-effective solutions for easy, “down-and-dirty” applications. These systems are simpler to setup, however they cannot make up for products which may be slightly conductive, because of the presence of moisture, acidity, or additives like carbon black.
Balanced-coil systems offer product-effect compensation that suppresses false signals brought on by the item. The advantage is always to prevent rejecting perfectly good material. Analog versions need the operator to manually reset the compensation as material moisture content or some other variable changes. Newer digital versions may be preset to self-adjust for many different products or an array of moisture content or other variables in a product.
Making feeling of sensitivity – Electronic metal detectors are high-tech, sensitive devices that really must be handled with some care. Excessive vibration from motors, chains, along with other nearby equipment could cause a detector to emit a false signal and reject good material.
You shouldn’t have to sacrifice good material for accurate detection and rejection. As well as product-effect compensation, state-of-the-art Food Checking Weigher offer adjustable sensitivity and positive speed control to minimize the volume of material lost.
Maximum sensitivity of the detector determines the minimum dimensions of metal particle that it can sense. Smaller particles can slip through, so this factor is vital to choosing the proper detector to have an application. Maximum sensitivity is measured by loading a sample of resin with steel spheres and taking the measurement in the middle of the coil, in which the sensitivity is lowest. Steel spheres are utilized because these people have a uniform, defined size, which means that the measurements are repeatable. Also spherical particles are definitely the most challenging to detect due to their relatively low area.
All metal separators usually are not equally sensitive. True sensitivity depends on the dimensions of the search coil. The smaller the search coil, the lesser the metallic particle that can be detected with maximum sensitivity. A great principle to be aware of is the fact that normal sensitivity is approximately 1% in the diameter from the coil. Based on the sensing aperture, innovative pbgavn are designed for detecting contaminants no more than .4 mm.
Sensitivity can also be linked to the composition and model of the content. Although electronic all-metal separators will detect ferrous particles, stainless-steel, lead, aluminum, bronze, tin, and much more, they may be most sensitive to ferrous particles. This is because metallic particles are detected by means of eddy currents, and the greater the eddy current the larger the sensitivity. Eddy currents on the surface of ferrous particles are higher than those generated on the surfaces of aluminum, bronze, or copper particles, which means that the sensitivity of ferrous particles is greater than the second. What’s more, eddy currents from metallic particles are merely effective on the surface, so the greater the surface, the larger the sensitivity. Because of this flat metallic particles, or particles with irregular shapes, are much better to detect than spheres.
Another feature offered by Food X-Ray Inspection Machine is known as positive speed control. Due to variations in bulk density, metal particles may not travel by way of a pneumatic conveying line on the same speed because the resin itself. Positive speed control senses the actual conveying speed in the metal contaminants and automatically adjusts the open time of the rejection valve in order to remove the metal with a minimum of resin loss.
Junhong Electronic&Technology (Dongguan) Co., Ltd is a professional manufacturer since 2005, specialized in R&D of security detection technology. We have various of products range: Walk through metal detectors, hand held metal detectors, X-ray luggage scanners, X-Ray Body Scanner, Underground Metal Detector, Industrial Metal Detector, Checkweigher, Infrared Body Temperature Detection System; Explosives Detector, Under Vehicle Surveillance Systems; etc.
Office: +86-769-22688609, 22688610, 22688612
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Address: No.23, Xintian street, Baizhoubian, Dongcheng district, Dongguan city, China