The hydraulic system of large multifunctional VIM furnaces is complex. It involves a wide layout of pipelines, many valve groups, and numerous actuators. To ensure the efficient operation of each actuator, the system is divided into several independent hydraulic units. Each unit is responsible for a specific operation. For example, in a 6-ton VIM furnace, the system is divided into three hydraulic units. Each unit has its own hydraulic station and valve group. This design meets the requirements of different processes.
Hydraulic Unit 1 Design
Hydraulic Unit 1 is the largest in the entire hydraulic system. It must handle the demands of multiple actuators. This ensures the smooth operation of the melting and casting processes. The specific configuration is as follows:
- Oil tank volume: 800L. This volume ensures stable system operation and provides sufficient oil for hydraulic functions.
- Pump and motor configuration: A dual-pump, dual-motor system is used. One pump serves as a backup. This guarantees continuous operation, even if the main pump fails.
- Working pressure: The system is designed to operate at pressures between 8 MPa and 12 MPa. This range offers flexibility for various operating conditions.
- Maximum pressure: The system is designed to withstand up to 24 MPa. This ensures safe operation under high-load conditions.
Unit 1 primarily provides hydraulic power for all actuators, including cylinders and motors. The system ensures smooth oil pressure output and reliable energy transfer.
Hydraulic Unit 2 Design
Hydraulic Unit 2 is dedicated to supporting the tilting and casting processes. It ensures the safety and efficiency of these operations. The configuration is as follows:
- Oil tank volume: 300L. This volume is enough to support high-frequency operations for short periods.
- Pump and motor configuration: A dual-pump, dual-motor system is used, with one pump as a backup. This improves reliability and safety.
- Working pressure: The system operates at a pressure of 8 MPa to 12 MPa. It can handle a maximum pressure of 24 MPa, which meets the high-load demands during casting.
Unit 2 serves two main functions:
- Melting process: During melting, the hydraulic system uses a backward-tilting horizontal cylinder to tilt the furnace body. This prevents metal bridging, ensuring uniform melting.
- Casting process: During casting, the hydraulic system tilts the furnace forward to pour the molten steel. The tilting cylinder is equipped with a safety valve. This valve prevents accidents caused by hose ruptures or hydraulic failures. The valve must be installed at the oil inlet of the cylinder to relieve pressure if necessary.
Cylinder structure design: The tilting cylinder uses a unidirectional, no-rod chamber. It also has a self-weight-return structure. During casting, the hydraulic proportional valve controls the oil flow into the cylinder. This precisely adjusts the tilting speed and direction. After casting, the cylinder returns to its original position using the self-weight of the crucible. Additionally, the return oil line is oil-free. It must connect to the T1 port of the oil tank and be positioned above the liquid level. This prevents oil-gas mixing and ensures proper venting.
Hydraulic Unit 3 Design
Hydraulic Unit 3 is simpler. It is primarily responsible for the ejection of the furnace lining and preliminary baking outside the furnace. The configuration is as follows:
- Oil tank volume: 300L. This volume provides enough hydraulic oil for low-frequency operations.
- Pump and motor configuration: A single-pump, single-motor system. This is a simple and cost-effective design.
- Working frequency and function: Unit 3 is used infrequently. The system operates independently. The primary functions are furnace lining ejection, forming, and preliminary baking.
Since Unit 3 operates less frequently, the design uses a simple, efficient hydraulic configuration to provide the necessary power for lining ejection and preliminary baking.
Conclusion Design of the Hydraulic System for Vacuum Induction Melting Furnace (VIM)
The hydraulic system design for the VIM furnace is complex and detailed. Different hydraulic units manage the needs of melting, casting, and external furnace operations. Proper design and configuration ensure the efficient operation of each part. They also ensure the safety of the equipment. Hydraulic Unit 1 handles the main tasks, Unit 2 ensures the safety of tilting and casting, and Unit 3 performs auxiliary functions such as ejection and baking. The system uses a dual-pump, dual-motor configuration and includes safety valves and other protective devices. This design improves reliability and reduces maintenance needs. The multi-unit, independently controlled approach enhances the system’s ability to handle varying operating conditions. It also improves safety, reliability, and operational flexibility.
