The closed-circuit cooling tower for medium-frequency furnaces is a high-efficiency, non-standard circulating cooling unit widely used in the cooling processes of these furnaces. It transfers heat generated within the furnace body to the cooling water via a circulating water system, thereby lowering the furnace temperature and ensuring its normal operation.
I. Description of the Closed-Circuit Cooling Tower for Medium-Frequency Furnaces:
Cooling water is critical for medium-frequency heating equipment. Insufficient water pressure, excessive water temperature, water supply interruption, impurities in the water, or pipeline blockages can all damage the power supply components and induction coils of the medium-frequency furnace. The requirements for the cooling water are as follows:
1、Cooling Water Quality Requirements
pH: 7–8.5 Suspended solids: <10 mg/L Alkalinity: <60 mg/L Conductivity: <0.5 μS/cm
Chloride ions: Average <60 mg/L; Maximum <220 mg/L
Sulfate ions: <100 mg/L Total iron: <2 mg/L
Soluble SiO₂: <6 mg/L Dissolved solids: <300 mg/L Total hardness: <10 degrees
2、Cooling Water System Design Requirements
Inlet water temperature: 5–30°C Water pressure: 0.2–0.3 MPa
Outlet water temperature: ≤55°C Water flow rate: 350 t/h
II. Operating Principle of the Closed-Circuit Cooling Tower:
1、Air-Cooling Section: The working fluid (soft water or other liquid) circulates within the cooling tower's heat exchanger coils. Heat from the fluid is absorbed by the coil walls and then expelled from the unit by the top-mounted fan.
2、Water-Cooling Section: When the fluid temperature exceeds the set limit, the spray system activates automatically. Spray pumps distribute water over the warm coil walls, forming a water film that absorbs significant heat through evaporation (latent heat of evaporation). A portion of the spray water turns into vapor and is carried away by the airflow, while unevaporated droplets fall into the collection basin for reuse in the next cycle. The fluid inside the coils circulates in a closed loop, resulting in theoretically zero consumption. Spray water consumption is minimal, amounting to only 0.1–0.2% of the flow rate.
Ⅲ. Advantages of the Closed-Circuit Cooling Tower for Medium-Frequency Furnaces:
1. The circulating cooling medium operates in a closed loop, preventing the entry of impurities and ensuring the purity of the medium. Soft water is used for the circulation loop, preventing scale formation and pipeline blockages. The unit has a compact footprint, allowing for flexible placement and relocation as needed, and features low energy consumption alongside simple, reliable operation.
2. Compared to traditional open-circuit cooling towers, this closed-circuit system utilizes a fully enclosed internal loop for the cooling water (purified water). This significantly reduces water waste and contamination, virtually eliminates the risks of corrosion and scaling for the Huaxin electric furnace, and is particularly suitable for enterprises and regions with strict requirements regarding industrial water quality and consumption.
3. The unit features an integrated self-contained water supply system. Installation and relocation are highly convenient as the system does not rely on external water reservoirs; the process involves only simple disconnection/reconnection of cooling pipelines and electrical wiring.
4. Automated electrical controls allow the system to adjust airflow and spray volume based on ambient temperature fluctuations, maximizing cooling efficiency and energy savings. Additionally, the control unit can be installed at various locations within the factory for remote operation and can be configured to synchronize automatically with the startup of the Huaxin electric furnace.
5. Manual and automatic settings for critical operating parameters—such as cooling water levels and inlet/outlet temperatures—combined with audible and visual alarms, eliminate the need for constant manual monitoring, ensuring a stable cooling process and precise cooling performance.
