Inspektion metallurgischer Brückenkräne: Wichtige Punkte zur Gewährleistung von Sicherheit und Betriebsstabilität

The article is mainly divided into four sections. It first clarifies the inspection methods for metallurgical overhead cranes, then summarizes common issues associated with these cranes, followed by specific inspection focuses and key precautions. The ultimate goal is to ensure the safe and stable operation of overhead cranes to meet the demands of metallurgical production.

Common Inspection Methods for Metallurgical Overhead Cranes

The commonly used inspection methods for metallurgical overhead cranes include the leveling instrument method, total station method, and tensioned steel wire method. Below is a detailed analysis and explanation of these methods:

Leveling Instrument Method

The leveling instrument method is one of the most frequently used techniques in the inspection of metallurgical overhead cranes. It is relatively simple to operate and primarily includes two approaches: high-altitude measurement and the suspended wire method.

• High-Altitude Measurement: This method involves properly positioning a leveling instrument in the metallurgical production area and placing a measuring staff on top of the rail pressure plate, creating a slight offset. The leveling instrument is then used to measure and accurately record various data.
• Suspended Wire Method: In this approach, a steel wire and measuring staff are suspended below the wire, while the leveling instrument is set up on a level ground surface. By comparing and analyzing the measurement data, potential issues within the crane system can be identified.

Total Station Inspection

The total station method effectively performs measurements of verticality and elevation differences. Compared to traditional methods, it utilizes electronic readings and allows for automatic recording and display of inspection data, ensuring higher accuracy. During crane inspection, once the total station is fixed in place, it can complete the full parameter inspection of the overhead crane, improving both efficiency and safety.

Tensioned Steel Wire Method

The tensioned steel wire method is primarily used to measure camber. A special steel wire rope is fixed at one end to the end beam of the metallurgical overhead crane. A weight is placed on the upper cover plate to tension the wire, while the other end is pulled tight using a 150N spring scale. By selecting appropriate measurement points, the vertical distance from the wire to the top surface of the main beam at mid-span is measured. The camber is then accurately calculated to determine whether there are structural or alignment issues with the crane based on the results.

Common Issues in Metallurgical Overhead Cranes

During operation, metallurgical overhead cranes inevitably encounter certain issues that can seriously affect their safety and operational efficiency, ultimately leading to reduced production performance. The most common problems include the following:

Rail Gnawing

Rail gnawing is one of the common issues in metallurgical overhead cranes. Typically, the widths of the crane’s and trolley wheels are relatively greater than the track gauge, creating a noticeable clearance between the wheel flanges and the rails. If the crane’s manufacturing quality is substandard or the installation process is not properly executed, the wheels may fail to maintain proper alignment with the rail center during operation. Instead, they may contact the side of the rail, resulting in severe wear. Over time, this causes flange deformation and leads to rail gnawing, which compromises the crane’s operational stability and increases maintenance needs.

Electrical Faults

Electrical faults are a key concern in the inspection of metallurgical overhead cranes. The main causes of such faults include:

• Poor Main Circuit Contact: The main circuit is an essential component of a metallurgical overhead crane, functioning similarly to a main air switch. It plays a crucial role in monitoring the system’s electrical status and identifying potential issues. However, during electrical inspections, if the busbar is not installed or has poor contact, any fault that occurs may not trigger a timely power cut-off, potentially leading to serious consequences.
• Cable Sheath Wear: Due to the complex environment of metallurgical production, overhead cranes are often affected by external factors during operation, which can reduce equipment quality and service life. In particular, cable sheaths are prone to wear and aging, which negatively affects the crane’s operational stability and safety. If the cable derails from its intended path, it may even be crushed, resulting in cable damage and increased safety risks.
• Improper Operating Practices: If operators fail to follow standard procedures during crane operation, and routine maintenance or inspection is neglected, or if personnel lack proper safety awareness, multiple safety hazards can arise. This not only threatens the crane’s safe operation but also affects production reliability.

Improper Installation

The operating condition of a metallurgical overhead crane is closely related to its build quality, especially the installation process. Improper installation can significantly undermine the crane’s stability. In severe cases, it may lead to accidents, causing financial losses or even injury. Common installation problems include:

• Foundation Not Matching Actual Conditions: If the crane’s foundation does not meet the requirements of the production site, it becomes difficult to support metallurgical operations. A lack of safety awareness or poor mastery of installation procedures among workers may result in deviations from standard practices, which compromises crane performance.
• Inadequate Clearance from Live Power Lines: According to operational safety standards, metallurgical overhead cranes must not come into contact with live power lines during use. Failure to maintain adequate safety distances between moving parts and power lines increases the risk of electrical hazards and equipment failure.
• Missing or Improperly Installed Safety Devices: If a load limiter is not installed during crane setup, the crane cannot operate within safe load limits, posing a major safety risk. Additionally, if other protective devices are installed incorrectly, emergency power shut-off may not function properly during a fault, disrupting operations and potentially endangering personnel.

Key Inspection Points for Metallurgical Overhead Cranes

Mechanical Inspection

• The main girder needs to be leveled. The height difference between the end bearing plates must not exceed 2 mm. If the crane adopts a double-girder structure, the shimming frame should be placed below the girders. However, for a single-girder structure, the center of the shimming support should be positioned 700 mm from the outer side of the plate. During the inspection, it is essential to ensure the accuracy of the level instrument placement, and the measuring staff should be accurately placed on the cover plate, making sure it is offset from the main web plate and separated from the rail pressing plate.
• Use the level instrument for measurement and calculate the average value based on the inspection data. Place measuring staffs at suitable positions on the cover plates of the three intermediate diaphragms, ensuring they are offset from the main web plate and kept clear of the rail pressing plates. At the same time, determine the camber location based on actual conditions and use the measurement data to identify problems and deal with them in time.

Electrical System Inspection

• It is necessary to inspect the zero-position protection in the electrical system of the metallurgical overhead crane to ensure that during operation, if the control handle on the operator console is not at the zero position, the system will not suddenly lose power. Also, if the operator is not at the console and fails to return the handle to the zero position, powering on may cause an accident. Therefore, zero-position protection plays a protective role. Proper inspection in this area can help avoid safety incidents.
• During the use of the metallurgical overhead crane, the controller can strictly control the electrical system. However, if the system cannot reset automatically, a protective device should be installed according to actual conditions to prevent accidents. If automatic reset is supported, the protective device may not be required. In addition, the power-on test method can be used to check whether the crane’s electrical system has any faults.
• Inspection of the grounding resistance is also an important task. The protective and repeated grounding must be reasonable and properly executed to ensure reliable current conduction.

Installation Process Inspection

Ensuring the quality of the installation process is key to improving the stability and safety of the metallurgical overhead crane’s operation. During the inspection of installation procedures, attention should be paid to the following points:

• According to the characteristics of the metallurgical overhead crane, a stable and reliable installation method must be adopted. The crane should be placed smoothly on the ground for installation to ensure stability and safety. In addition, a load limiter can be installed inside the crane’s structure to enhance safety. Once the crane exceeds the rated load, the device will automatically cut off power to reduce the risk of accidents.
• The installation should be carried out based on the actual conditions and requirements of the metallurgical production area to ensure the rationality of the installation process. Attention should also be paid to issues such as uneven or sloped ground in the production environment, and installation techniques should be improved accordingly. During installation, focus on the equipment’s load-bearing requirements and ensure that wiring and grounding are properly executed. Perform thorough inspection to confirm that the crane’s load-bearing capacity meets relevant requirements, thus effectively preventing safety accidents.
• To solve the issue of rail gnawing in metallurgical overhead cranes, installation deviations must be strictly controlled within an acceptable range. During the installation process, it is necessary to ensure that the wheels are level and aligned with the rails, with centered and vertical positioning. Also, ensure that the motor speed and power match to guarantee the normal operation of the metallurgical overhead crane.

Inspection Considerations for Metallurgical Overhead Cranes

• Prioritize Safety: According to relevant standards and regulations, safety should be treated as the top priority. Emphasis must be placed on safety inspections to comprehensively enhance the safety performance of metallurgical overhead cranes.
• Thoroughly Inspect Critical Components: Inspection work must be carried out meticulously, with particular attention paid to key and critical parts. The timing and frequency of inspections should be well managed. For instance, mechanisms such as the traveling and luffing systems require more detailed inspections, which should be performed repeatedly based on actual conditions to promptly eliminate safety hazards and ensure the equipment operates safely.
• Improve the Professional Competence of Inspectors: To ensure the effectiveness of the inspections, the professional skills of inspection personnel should be improved. This can be achieved through comprehensive evaluations involving appearance, performance, and safety aspects, continuously strengthening the inspectors’ technical level. In addition, any issues found during inspections should be addressed promptly, with thorough records kept describing the causes and locations of problems, providing a basis for future maintenance work.

Abschluss

Overhead cranes are widely used in metallurgical production and play a significant role in improving operational efficiency. However, due to the complex structure of metallurgical overhead cranes, inspection work must be taken seriously. By conducting routine inspections to identify common issues in a timely manner and implementing targeted solutions, the safe and stable operation of the equipment can be ensured. This helps eliminate or reduce potential safety risks and supports the smooth progress of metallurgical production.

Referenz: Key Inspection Points for Metallurgical Bridge Cranes

Cindy

WhatsApp: +86-19137386654

Email: cindywang@hndfcrane.com

Ich bin Cindy, habe 10 Jahre Berufserfahrung in der Kranbranche und eine Fülle an Fachwissen angesammelt. Ich habe für über 500 Kunden die zufriedenstellendsten Kräne ausgewählt. Wenn Sie irgendwelche Bedürfnisse oder Fragen zu Kränen haben, können Sie sich gerne an mich wenden. Ich werde mein Fachwissen und meine praktische Erfahrung nutzen, um Ihnen bei der Lösung des Problems zu helfen!