What is the principle behind detecting broken chains in slag scoopers?

Install a proximity switch next to the chain guide wheel of the slag skimmer; there is a sensing iron piece on the guide wheel. Under normal conditions, the chain of the slag skimmer drives the idler wheel to rotate, resulting in a change in the magnetic field between the proximity switch sensor and the induction iron piece. After amplification, it is converted into a switch signal for output; once the chain breaks or the idler wheel stops rotating, if no signal indicating the operation of the idler wheel is detected within 20 seconds, an alarm for a broken chain is issued, and at the same time the interlock mechanism for the slag skimmer is activated to stop driving the main motor.

Is it significant? If it works, we’ll add one of those as well. Over the past six months, the slag removal machines here have been failing frequently, either due to broken chains or scrapers·

Our factory uses cameras to monitor the screens in the DCS control room

I don’t think it’s necessary to have a chain break detection for the slag skimmer; if the chain breaks, the current change will be clearly evident.

Install a camera; manual monitoring is much better than relying on chain break detection. Chain break detection can only tell whether the chain has come loose, and it sometimes leads to false alarms that cause the machine to stop. A camera can not only detect chain breaks but also determine whether the scrapers are broken; if positioned appropriately, it can also show the operation of the drive wheel, as well as the amount of slag produced and its condition.

It’s useful; proximity switches are quite reliable, and they are generally used to detect broken chains in devices that rotate at low speeds. All the new slag skimming meters released in recent years have this function. An additional chain-cutting warning is also provided, which involves installing a travel switch at the top of the lifting device. I think the former is useful, while the latter isn’t very meaningful.

Advantages of HEKO high-strength wear-resistant chains: 2.1. Compared to manganese-containing alloy steel (23MnCrNi), chromium-nickel-molybdenum alloy steel used in HEKO high-strength wear-resistant chains provides better corrosion protection. 2.2. These chains allow for a greater depth of carburization. 2.3. The toughness of the chain’s core is improved, which helps to prevent breakage due to cracks. 2.4. The hardness of the core of HEKO chains is higher than that of chains conforming to DIN 764 or DIN 22252-2 standards. 2.5. Compared to chains that comply with the DIN 764 standard, Heko chains have a breaking strength that is 400 N/mm2 higher. Therefore, the break safety factor of HEKO chains is much higher than that of chains according to the DIN 764 standard. 2.6. The Heko400E chain features a better quenching control program during heat treatment. Therefore, its quality is more stable. 2.7. Heko chains have a longer service life. 4-5 times higher than DIN22252-2. 4.1.3 Product Technical Introduction: The Heko carburized and hardened chains that meet Heko’s 400E quality standards are made from high-grade chromium-nickel-molybdenum (14CrNiMo5) alloy steel. 1) Product advantages/features: Advantages of chromium-nickel-molybdenum carburized and hardened chains: a) A high content of chromium alloy ensures stable hardness and hardenability for the product. b) A high content of nickel alloy enables the chain to possess greater toughness, thereby resulting in higher fatigue resistance. c) A high content of molybdenum alloy increases the depth to which hardness penetrates, ensuring that larger-sized chains have the same uniform hardness across their cross-section. d) Lower sulfur and phosphorus contents – high levels of these elements have a negative effect on the toughness of the chain. e) Plasticity of low-carbon alloy steel; schematic diagram of the carburized layer in the chain section. In summary, chains manufactured using chromium-nickel-molybdenum alloy steel instead of manganese steel offer the following advantages: – Better corrosion resistance – Potentially higher central toughness, thereby increasing the chain’s breaking strength and safety – Higher fatigue resistance – Greater depth of carburization after quenching. HEKO Chain Company is currently the only one to use the world’s most advanced vacuum carburizing furnaces for heat treatment of chains. 2) Product manufacturing process: After purchasing the raw materials for chain production, they are inspected to ensure that they meet relevant standards; their chemical composition is also checked using a spectrometer, and only materials without any defects are used. The manufacturing process of chains involves cutting the wire to specific dimensions, heating it, then bending it, and finally performing flash welding or resistance welding. During this process, the parameters of the material, such as upset pressure and current, are directly incorporated into the control system, which automatically calculates and controls the entire welding process. The welded chain is then subjected to a tuning process. The heat treatment processes near the chains and connectors are carried out entirely under automatic control. The controller can collect and monitor the entire process inside the carburizing furnace, and automatically save all parameters. The manufactured chains are subjected to tensile testing, and the test process is recorded as curves and graphs. The surface hardness of the chain also needs to be measured, and all the results are reflected in the test report. It can be provided to customers. The attached illustrations show Germany’s Heko chain company’s methods for chain testing and material analysis; the computer can display the composition of the materials. They also feature photos of Heko’s manufacturing facilities, as well as the raw materials used for chains and the welding processes. Heko places a strong emphasis on innovation in production techniques, and it uses state-of-the-art vacuum carburizing furnaces – a technology that only this company possesses among those engaged in chain production. This vacuum carburizing furnace overcomes the capacity limitations of traditional carburizing furnaces, greatly improving production efficiency as well as the precision of chains. Heat treatment carburizing process; Equipment for testing precision tolerances in chain manufacturing (to ensure the accuracy of chain pairing); Chain holder used in breaking load tests (to measure tensile strength). For more detailed information, please contact us: HEKO Chains Germany’s representative office in Beijing. Contact person: Sun Hailin. Phone number: 15010514257

I believe that the current value of the slag skimmer should be set to trigger high-level alarms; the control room staff should pay close attention to monitoring this current value, as it can reveal many issues.

The chain break detection switch in our factory fixes the probe to the slag skimmer located outside the idler wheel at the point where the descending chain turns from an inclined position to a horizontal one. There is a protrusion on the side of the idler wheel facing the probe at an angle of 60 degrees; the probe measures the distance between itself and the idler wheel. If this distance does not change within 15 seconds, a signal is sent to stop the slag skimmer.

It is very necessary to increase surveillance; cameras are sufficient, and adding more chains would increase the possibility of parking