If you are recycling plastic goods or processing virgin materials, making a product free from metal contaminants is much more important today than ever before. Trends to thinner walls, tinier hot-runner nozzles, and more expensive and sophisticated machinery and tooling suggest that even the smallest bit of tramp metal can cause costly problems.
Processors often do not recognize the value of Gold Metal Detector Long Range. Even virgin material can acquire metal contaminants at various stages of manufacturing and transportation, right until the second it enters the throat of your own molding or extrusion machine. Contamination may range from tiny particles worn off by equipment abrasion to entire nuts or bolts loosened by vibrations in processing machines. There’s even the human factor: Inevitably, items including coins, pens, and paper will occasionally belong to the item stream.
For that reason, metal-detection technology can be used through the entire plastics industry to safeguard processing equipment and to ensure product purity. Metal detectors keep your product under strict surveillance constantly preventing unnecessary machine downtime and costly maintenance.
When we speak of “metal detectors,” some processors might think first of magnets. These are used effectively before the metal detector for capturing ferrous metals. Less familiar to many processors are electronic detectors for all sorts of metals. These are generally active devices that actuate a valve or other device to reject the contaminated material.
What’s more, electronic metal detectors could be monitored remotely from a personal computer. This capability offers a record of where and how frequently contamination occurs in your plant. Such valuable data can help you compare the purity of different vendors’ resins or diagnose excessive machine wear.
How metal detection works – There are two basic types of metal detectors:
Single-coil systems – When a metallic particle falls through the high-frequency electromagnetic field, an eddy current is induced in the particle, thereby removing energy through the coil system. Because of this the maximum amplitude of the coil’s vibration decreases. More energy is then supplied to increase the amplitude returning to maximum level. This disturbance of the coil’s vibration is detected by the electronic circuit as signaling the existence of a metallic particle.
Balanced-coil system – Single-coil systems provide inexpensive solutions for simple, “down-and-dirty” applications. These systems are simpler to create, however they cannot make amends for products that could be slightly conductive, due to the existence of moisture, acidity, or additives like carbon black.
Balanced-coil systems offer product-effect compensation that suppresses false signals due to the merchandise. The main benefit would be to prevent rejecting perfectly good material. Analog versions require the operator to manually reset the compensation as material moisture content or other variable changes. Newer digital versions could be preset to self-adjust for various products or a variety of moisture content or some other variables inside a product.
Making feeling of sensitivity – Electronic metal detectors are high-tech, sensitive devices that must definitely be handled with some care. Excessive vibration from motors, chains, as well as other nearby equipment may cause a detector to emit a false signal and reject good material.
You shouldn’t must sacrifice good material for accurate detection and rejection. As well as product-effect compensation, state-of-the-art X Ray Machine offer adjustable sensitivity and positive speed control to lower the volume of material lost.
Maximum sensitivity of any detector determines the minimum dimensions of metal particle that it could sense. Smaller particles can slip through, so this factor is vital to selecting the proper detector for the application. Maximum sensitivity is measured by loading a sample of resin with steel spheres and taking the measurement in the midst of the coil, in which the sensitivity is lowest. Steel spheres are employed because these people have a uniform, defined size, meaning the measurements are repeatable. Also spherical particles would be the most difficult to detect due to their relatively low surface.
All metal separators are certainly not equally sensitive. True sensitivity depends on the scale of the search coil. The smaller the search coil, smaller the metallic particle which can be detected with maximum sensitivity. A great principle to be aware of is that normal sensitivity is all about 1% in the diameter in the coil. Based upon the sensing aperture, innovative pbgavn are designed for detecting contaminants no more than .4 mm.
Sensitivity is also related to the composition and model of the fabric. Although electronic all-metal separators will detect ferrous particles, stainless-steel, lead, aluminum, bronze, tin, and more, these are most understanding of ferrous particles. That is because metallic particles are detected by means of eddy currents, and the greater the eddy current the higher the sensitivity. Eddy currents on the surface of ferrous particles are greater than those generated on the surfaces of aluminum, bronze, or copper particles, which means that the sensitivity of ferrous particles is higher than the latter. What’s more, eddy currents from metallic particles are merely effective on the surface, so the larger the surface, the larger the sensitivity. This means that flat metallic particles, or particles with irregular shapes, are quicker to detect than spheres.
Another feature provided by Airport Walkthrough Metal Detector is known as positive speed control. Due to differences in bulk density, metal particles might not travel through a pneumatic conveying line at the same speed because the resin itself. Positive speed control senses the specific conveying speed in the metal contaminants and automatically adjusts the open time of the rejection valve in order to remove the metal having 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.
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