Whether you are recycling plastic goods or handling virgin materials, creating a product free from metal contaminants is much more important today than in the past. Trends to thinner walls, tinier hot-runner nozzles, and more pricey and sophisticated machinery and tooling mean that even the smallest bit of tramp metal can cause costly problems.
Processors often tend not to recognize the significance of High Depth Ground Gold Metal Detector. Even virgin material can acquire metal contaminants at various stages of manufacturing and transportation, right until the moment it enters the throat of your molding or extrusion machine. Contamination can 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 like coins, pens, and paper will occasionally fall into the merchandise stream.
For this reason, metal-detection technology is used throughout the plastics industry to safeguard processing equipment and to ensure product purity. Metal detectors keep your product under strict surveillance constantly and stop unnecessary machine downtime and costly maintenance.
When we talk about “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 any other device to reject the contaminated material.
What’s more, electronic metal detectors can be monitored remotely from a pc. This capability offers a record of how and where 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 – The two main basic kinds of metal detectors:
Single-coil systems – Each time a metallic particle falls through the high-frequency electromagnetic field, an eddy current is induced inside the particle, thereby removing energy through the coil system. Consequently the utmost amplitude of the coil’s vibration decreases. More energy will be supplied to increase the amplitude back to maximum level. This disturbance in the coil’s vibration is detected through the electronic circuit as signaling the presence of a metallic particle.
Balanced-coil system – Single-coil systems provide inexpensive solutions for simple, “down-and-dirty” applications. These systems are easier to create, however they cannot make up for products which may be slightly conductive, because of the existence of moisture, acidity, or additives like carbon black.
Balanced-coil systems offer product-effect compensation that suppresses false signals due to the item. The benefit is always to prevent rejecting perfectly good material. Analog versions require the operator to manually reset the compensation as material moisture content or any other variable changes. Newer digital versions can be preset to self-adjust for different products or a range of moisture content or some other variables inside a product.
Making sensation 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 must sacrifice good material for accurate detection and rejection. In addition to product-effect compensation, state-of-the-art Gold Mine Detector offer adjustable sensitivity and positive speed control to lower the volume of material lost.
Maximum sensitivity of any detector determines the minimum size of metal particle that it can sense. Smaller particles can slip through, so this factor is essential to deciding on 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 center of the coil, where sensitivity is lowest. Steel spheres are utilized because they have a uniform, defined size, which means that the measurements are repeatable. Also spherical particles would be the most difficult to detect because of their relatively low surface area.
All metal separators are not equally sensitive. True sensitivity depends on the size of the search coil. The smaller the search coil, the smaller the metallic particle which can be detected with maximum sensitivity. A good principle to bear in mind is the fact normal sensitivity is approximately 1% from the diameter of the coil. Based on the sensing aperture, innovative pbgavn are capable of detecting contaminants no more than .4 mm.
Sensitivity is also related to the composition and model of the content. Although electronic all-metal separators will detect ferrous particles, stainless-steel, lead, aluminum, bronze, tin, and more, they may be most understanding of ferrous particles. This is because metallic particles are detected by way of eddy currents, and the higher 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, meaning that the sensitivity of ferrous particles is higher than the second. 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 Under Vehicle Checking Mirror is called positive speed control. Because of differences in bulk density, metal particles may not travel via a pneumatic conveying line in the same speed as the resin itself. Positive speed control senses the specific conveying speed from 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.
Office: +86-769-22688609, 22688610, 22688612
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Email: [email protected]
Address: No.23, Xintian street, Baizhoubian, Dongcheng district, Dongguan city, China