Wuxi Wondery Industry Equipment Co., Ltd

I. Project Background and Equipment Application Positioning This case study involves a ladle heating station used for preheating ladle linings after repair and before receiving molten metal. The core function of the equipment is to provide smooth and controllable heating of the lining prior to casting, in order to stabilize the casting temperature regime, reduce metal loss, and ensure process repeatability. The operating environment is an industrial workshop, requiring stable operation across multiple heating cycles. The station is designed to accommodate a conical ladle with a 1-ton molten steel capacity. The ladle has an internal top diameter of 500 mm, internal bottom diameter of 410 mm, and depth of 900 mm; the external top diameter is 770 mm, and the overall height is 1,050 mm. These dimensions establish the geometric boundary conditions for heating element arrangement and station structural design – the conical inner cavity means the radial spacing of heating elements varies along the height direction, precluding the conventional arrangement used for equal-diameter cylindrical furnace chambers. II. Heating System Technical Parameter Requirements The equipment requires electric heating with a total installed power of no less than 30 kW. Heating elements are resistance type, required to withstand high-temperature long-term operation and cyclic thermal loading. The maximum heating temperature must be no less than 800°C, and the heating element temperature must exceed the lining working temperature to ensure sufficient heat transfer intensity without localized overheating. There are inherent constraints among these parameters: an 800°C lining target temperature means the heating element surface temperature must be maintained at a higher level to establish an effective radiative heat transfer differential. If the element surface load is set too high, heat transfer intensity increases but element life under cyclic thermal loading is shortened; if set too low, heating time is extended. Therefore, element material selection and surface load design constitute the core technical trade-off of this project. III. Temperature Uniformity and Control Accuracy Requirements The technical requirements specify two temperature indicators: system temperature stability control accuracy of at least ±10°C, and internal ladle temperature differential not exceeding 50°C. Uniform heating of the ladle inner surface is required along the full height, meaning the type and arrangement position of heating elements must be specifically selected in conjunction with the conical ladle geometry to minimize temperature gradients. The design challenge presented by the conical structure is that the lower section has a smaller diameter while the upper section has a larger diameter. If vertically suspended straight rod elements were used, the spacing between the lower section and the lining would be greater than at the upper section, resulting in insufficient radiative heat transfer intensity at the bottom. Therefore, elements may require segmented arrangement or non-standard geometry to compensate for this geometric difference. The control system must be capable of operating automatically according to a given heating curve, and also allow manual control of main parameters. Temperature control is achieved through real-time thermocouple monitoring, with real-time parameters displayed on the operation panel. Lining heating must be smooth and controllable, eliminating abrupt temperature changes – this requirement points to a heating rate limitation function, meaning the control system requires slope control capability rather than simple on-off temperature regulation. IV. Structural and Safety Design Requirements The heating unit must be insertable into the ladle interior and lockable in the working position. Heating elements must have protective structures to prevent mechanical damage and contact with the lining, such as heat-resistant steel protective mesh or protective sleeves. This requirement stems from actual operating conditions: during ladle lifting and positioning, positional deviation exists, and without protection, elements could be damaged by collision with the lining or ladle wall. Cable routing and connection points must be constructed from high-temperature-resistant materials suitable for high-temperature operation. The equipment structure must facilitate maintenance, allowing heating element replacement without complete disassembly – an important availability indicator, since heating elements are periodic consumables and replacement convenience directly affects equipment downtime. Safety requirements include short circuit, overload, and leakage protection devices, as well as emergency stop, over-temperature protection, and abnormal condition interlock protection functions. Hazardous areas must have structural guards to prevent accidental personnel entry. The equipment must be grounded per code, with no accessible live parts under normal operating conditions. Protection scope covers three risk categories: electric current injury, high-temperature injury, and injury from moving and rotating equipment parts. V. Environmental Adaptability and Power Supply Conditions The equipment is powered by AC 380V, 50Hz. The operating environment temperature range is +5°C to +40°C. The equipment structure must be resistant to dust, vibration, and other factors typical of metallurgical production conditions. This environmental requirement imposes constraints on the protection rating and cooling method of the electrical control cabinet – the dust and vibration environment of a metallurgical workshop is unsuitable for conventional open cooling structures. VI. Scope of Supply and Documentation Requirements The scope of supply includes the complete heating station, comprising heating elements, control cabinet, temperature measurement system, and connecting cables. Supply completeness must ensure the equipment can be directly commissioned without additional procurement of major components. Technical documentation includes operation manual, electrical schematic diagrams, general assembly drawings, and installation instructions, sufficient to ensure safe operation and maintenance of the equipment. VII. Service Life and Technical Support Requirements The warranty period is no less than 12 months from the date of commissioning. During the warranty period, faults and defects attributable to the manufacturer shall be rectified by the supplier. Under compliant operating conditions, equipment service life is no less than 5 years. The equipment must reach the set heating temperature within a reasonable process time agreed with the customer, and ensure parameter stability across multiple heating cycles for repeatable process operation. The control system must have high reliability and resistance to industrial interference. Technical support scope includes operational technical consultation, melting mode setup recommendations, and technical assistance under emergency conditions

I. Caractéristiques du projet et spécifications des équipements Cette étude de cas concerne un four à séchage rapide vertical en alliage d'aluminium avec une zone de travail efficace de 1200 × 1200 × 1100 mm (diamètre × hauteur).Il s'agit d'un four de chauffage à résistance à cycle utilisé principalement pour le traitement des solutions et l'éteinte rapide des pièces moulées et des plaques en alliage d'aluminiumL'équipement a une puissance nominale de 135 kW, une tension nominale de 380 V à trois phases de 50 Hz et une température nominale de 650 °C avec température de fonctionnement réglable. Le positionnement structurel de cet équipement diffère des fours d'extinction classiques de type boîte: les pièces sont suspendues à l'intérieur du four.et le réservoir d'extinction est situé directement sous le corps du fourAprès l'ouverture de la porte du four, la pièce peut tomber directement dans l'eau. Cette disposition verticale est la base physique pour un transfert rapide. II. Contrôle de la température et conception des zones Le système de contrôle de la température utilise une architecture à deux niveaux. Le niveau supérieur est un écran tactile de 10 pouces responsable du réglage, du contrôle, de la surveillance, de l'enregistrement,et stockage des courbes du processus de traitement thermiqueLe niveau inférieur utilise des régulateurs de température PID industriels Eurotherm 3504 avec une précision de contrôle de ±1°C et une uniformité de température du four à ±3°C pendant la phase de rétention. Les zones de chauffage sont configurées en 2 zones reliées en configuration étoile.alarme sonore et visuelle de surchauffeLe régulateur de température dispose d'une fonction d'auto-ajustement en ligne qui calcule les paramètres PID optimaux en fonction des caractéristiques thermiques réelles du four,taux de chauffage de compensation contre les dépassements. III. Configuration du revêtement du four et de l'élément chauffant La doublure du four utilise du coton à fibres réfractaires standard, les murs et le toit étant construits en structures entièrement en fibres avec une épaisseur d'isolation totale d'au moins 240 mm.Les blocs pliés en fibres subissent une précompression secondaire avant l'installation, atteignant une densité de compression d'au moins 230 kg/m3, et sont fixés à la coque du toit du four avec des barres rondes en acier inoxydable.,Les composants de fixation sont estampillés à partir de tôles d'acier inoxydable 1Cr18Ni9Ti. Les éléments de chauffage sont des bandes de résistance en alliage 0Cr25Al5, pressées avec des moules dédiés pour éviter les dommages du traitement.permettant une maintenance et un remplacement pratiques et rapides- lors de l'installation, des éclaboussures en céramique sont placées entre la paroi de fibre et la bande de résistance pour éviter tout contact direct entre la surface de fibre et la bande,augmentant ainsi la dissipation de chaleur de la bandeLes vis en céramique et les rondelles sont toutes deux fabriquées à partir d'un matériau à haute teneur en alumine et frottées à haute température pour assurer une résistance et une durée de vie suffisantes.Les bandes de résistance sont suspendues autour de la chambre du fourLes éléments de chauffage utilisent une connexion étoilée, avec une charge de surface contrôlée inférieure à 1.6 W/cm2 ¢ une valeur inférieure à la limite de conception conventionnelle pour les bandes de résistance, destinés à prolonger la durée de vie des éléments en fonction de cycles de chauffage et de refroidissement fréquents. IV. Système de circulation de l'air chaud et de guidage de l'air Un ventilateur de circulation résistant aux hautes températures de 7,5 kW est installé sur le toit du four.avec roulements refroidis par air pour accueillir l'environnement de toit à haute températureLe capot de guidage de l'air maximise la composante longitudinale de la force centrifuge générée par le ventilateur, pressant l'air chaud vers le bas.L'air passe ensuite par la pièce à usiner et est ramené dans l'entrée du ventilateur par le bas, formant une boucle de circulation fermée.Cette trajectoire de flux d'air assure l'uniformité du champ de température à l'intérieur de la chambre du four et est une conception de support pour la méthode de chargement par suspension , permettant le passage de l'air. V. Mecanisme de levage du panier et de verrouillage de la porte du four Le mécanisme de levage du panier est constitué d'un treuil électrique, d'une chaîne de levage à anneaux et de blocs de poulies.Le treuil est une unité électriquement contrôlée à double vitesse avec une vitesse de câble allant jusqu'à 18 mètres par minute, répondant à l'exigence d'une descente rapide dans l'eau; la phase de montée utilise une vitesse lente pour réduire l'impact d'inertie lorsque la pièce et le panier entrent dans le four.Le treuil est équipé d'un système de commande de l'inclinaison et d'un dispositif d'auto-verrouillage.Le système de poulie est installé sur la partie supérieure du corps du four.composé de 4 poulies et de 4 ensembles de roulements, assurant un levage et un abaissement fluides du panier. La porte du four est située au bas du corps du four et se déplace latéralement, avec des rails de guidage sur le côté pour maintenir le mouvement horizontal.Lors de la fermeture, le cylindre pousse la porte à la position fermée et continue à exercer la pression, en soulevant la porte vers le haut via un mécanisme de levier sur le côté pour la pousser fermement contre le corps du four.Le mécanisme de levage et le mécanisme de la porte du four sont verrouillés: le mécanisme de levage ne peut être alimenté et utilisé qu'après ouverture complète de la porte du four (à ce moment-là, l'alimentation de l'élément chauffant a été coupée).Cette logique de verrouillage empêche les dommages de l'équipement de dysfonctionnement lorsque la porte n'est pas ouverte. VI. Temps de transfert d'extinction et réservoir d'extinction Le temps de transfert d'extinction est défini comme le temps entre l'ouverture de la porte du four et l'immersion complète de la pièce en eau, avec une exigence de conception ne dépassant pas 10 secondes.Ce paramètre est essentiel pour le processus de traitement de la solution d'alliage d'aluminium, plus la vitesse de refroidissement est élevée dans la plage sensible à l'éteinte, et plus l'effet de renforcement du vieillissement est bon. Le réservoir d'extinction est de construction mobile, entraîné par un moteur de 2,2 kW. Deux pompes de circulation de 3 kW sont installées dans le réservoir pour agiter continuellement l'eau pendant l'extinction,maintenir une température d'eau uniforme et accélérer le transfert de chaleur de la surface de la pièceLe réservoir est soudé à partir d'une plaque d'acier d'une épaisseur de 5 mm et testé pour l'étanchéité.avec la section avant servant de zone de table de travail du cadre de matériau et la section arrière servant de réservoir d'eau, avec trois ensembles de roues (un ensemble étant des roues motrices). VII. Séquence d'action du processus La séquence d'action complète de l'équipement est la suivante: manual loading → quenching cart moves to below the furnace body → furnace door opens → material frame lifting mechanism descends → manual hooking → material frame rises → furnace door closes → heating and holding according to process time → solution treatment ends → stirring water pump starts → furnace door opens → material frame descends → material frame rapidly enters water for quenching → material frame rises → quenching cart exits → material frame descends → manual unhooking followed by return to furnace opening → furnace door closes → manual unloading → next cycle begins.

I. Project Background and Equipment Specifications This case study involves a medium frequency induction melting furnace, model WDL-KGPS-500, with a rated capacity of 0.5 tons and a maximum capacity of 0.6 tons, designed for aluminum melting applications. The equipment employs medium frequency induction heating and is equipped with a hydraulic tilting system for molten aluminum discharge. The most notable configuration feature of this equipment is its grid compatibility scheme: the power supply side is fed at 440V/3P/60Hz, while the medium frequency power supply input voltage is specified at 380V. This means the equipment is intended for 60Hz grid regions (such as South Korea, parts of Central and South America, and the Middle East), requiring a transformer or voltage adaptation unit either inside or external to the power supply cabinet to step down the 440V grid voltage to 380V before feeding the medium frequency power supply. This dual adaptation of both voltage and frequency is a parameter that must be confirmed upfront during the electrical design phase for export projects. II. KGPS Medium Frequency Power Supply System The power supply system adopts the KGPS thyristor-based medium frequency power supply, with a rated power of 400 kW, a medium frequency output voltage of 2400 volts, and an output frequency of 1000 Hz. The power factor exceeds 0.9, and the startup success rate is 100%. The rectifier section is a three-phase full-controlled bridge with a three-phase six-pulse rectifier structure and a parallel-connected inverter. The control circuit employs an eighth-generation digital circuit board architecture, featuring wide frequency range adaptability, constant power control, swept-frequency zero-pressure soft start, and dual closed-loop voltage-current feedback. The swept-frequency zero-pressure startup means the system automatically scans frequencies during startup, establishing medium frequency oscillation upon finding the load resonant point – avoiding the sensitivity to load parameter variations inherent in separate-excitation startup methods. The protection system encompasses overcurrent, overvoltage, undercurrent, undervoltage, water loss, and phase-loss conditions. When any protection parameter exceeds the set threshold, the system automatically blocks pulse output and disconnects the main circuit power. The power supply cabinet panel includes full voltage, current, and power readings along with operating status indicators. The capacitor cabinet provides medium frequency parallel compensation, reducing reactive power transmission losses on the distribution lines. The capacitor bank capacity is matched to the resonant frequency of the induction coil, ensuring operation near the resonant point under rated conditions. III. Induction Coil Design and Magnetic Yoke Shielding The induction coil is the core energy conversion component, constructed from T2/TU1 copper with a wall thickness of 4 mm. When energized, the coil generates a 1000 Hz alternating magnetic field that induces eddy currents in the metal charge within the furnace hearth, generating heat. The coil design is based on electromagnetic field principles and verified through dedicated computer software, with the deviation between actual operating power and design power controlled within 5%. Turn-to-turn insulation is processed using advanced insulation techniques, with dedicated clamping technology reducing axial vibration of the coil. The coil inner wall is sprayed with imported high-temperature-resistant insulating materials, and a furnace lining leakage alarm system is installed – when molten aluminum seeps into the coil layer, the system detects it early and signals the condition, preventing furnace breakout incidents. A refractory coating of 10 to 15 mm thickness is applied to the inner surface of the coil, serving both to facilitate furnace lining construction and to prevent thermal deformation of the lining. The magnetic yokes are of crescent profile construction, laminated from cold-rolled silicon steel sheets and clamped with stainless steel splints. The contact surface between the yoke and the coil outer surface is curved, providing face contact rather than line contact, achieving better clamping efficiency and reduced magnetic flux leakage. The silicon steel sheets are reinforced with dedicated splints rather than through-bolts, maximizing the effective magnetic area and reducing localized heating. The magnetic yokes simultaneously shield magnetic flux leakage, prevent furnace body heating, and support and secure the induction coil. IV. Hydraulic Tilting System Furnace tilting is driven by a hydraulic system with two cylinders arranged on both sides of the furnace body for lifting, with furnace return accomplished by gravity. The hydraulic station is equipped with dual motors and dual pumps – one in service and one on standby, with automatic switching capability. The fuel tank is fully enclosed and welded to prevent hydraulic oil leakage. The tilting angle range is 0 to 95 degrees, with smooth operation without shock or creeping, adjustable speed, and the ability to hold at any position. Tilt operation is controlled via manual valves, suitable for casting processes requiring precise control of molten aluminum pouring volume. V. Crucible Mold and Lining Formation A configuration detail of this equipment is that it supplies a crucible mold rather than a finished graphite crucible. The crucible mold is formed from 3 mm iron plate and is used to control the shape and volume positioning of the refractory lining during formation. The user must select the lining material and ramming/sintering method according to the specific metal being melted and the casting process – a difference at the user operation level compared to solutions that directly supply finished graphite crucibles. The positioning function of the crucible mold ensures dimensional consistency of the lining cavity, thereby maintaining the coupling distance between the furnace hearth and the induction coil stable within the design range. VI. Water Cooling System and Cooling Cables The water-cooled cables are constructed from TU1 multi-strand oxygen-free copper wire, sheathed in high-strength fire-resistant rubber tubing, with cold-formed connectors ensuring contact resistance and tensile strength. The power supply side requires a cooling water flow rate of no less than 8 m³/h, while the furnace body side requires no less than 12 m³/h. The outlet water temperature on the power supply side must not exceed 35°C, and on the furnace body side must not exceed 45°C, with inlet water pressure maintained between 0.15 and 0.35 MPa. The water cooling system employs a fully enclosed circulating cooling method using soft water as the circulating medium. The core advantage of soft water circulation lies in avoiding overheating damage to the power supply, thyristors, capacitors, IGBT modules, and induction coil caused by scale deposition; additionally, soft water contains no ionic conductive components, so cooling components will not be damaged by electrolysis. The system requires no water pool or cooling tower, occupies minimal floor space, and has low makeup water consumption. The cooling system consists of three parts: main machine, water tank, and control box. The main machine includes the housing, copper cooler, exhaust system, spray system, water separator, collecting annulus, and spray pump. The water tank includes the main pump (one in service, one standby), stainless steel water tank, electrical cabinet, temperature control system, and pressure control system. The control box enables remote operation of the water cooling system, displaying water temperature and allowing setup of delayed operation after work hours.