I. Overview The new generation K, DK (now named FKZ, FKCDZ according to the current safety standard certificate) series of mine energy-saving fans are designed by improving technology, perfecting structure, enhancing performance, and expanding the machine size based on the original mine energy-saving fans. This series of fans operates with higher efficiency, lower noise, a broader performance range, and more significant energy-saving effects. Additionally, the main wind筒 is equipped with a flow stabilizing ring device, with a characteristic curve free of humps, ensuring stable operation under any negative pressure condition. To expand the performance range of this series of fans and meet the needs of various large, medium, and small non-metallic mines, it is possible to select main fans, auxiliary fans, and multi-stage station fans operating in the high-efficiency range for all types of ventilation networks with low, medium, and high resistances and large, medium, and small air volumes. This series of fans uses two hub ratios of 0.40 and 0.45, and two structural types, single-machine and counter-rotating, which are divided into four types: K40, K45, DK40, and DK45. The K40 uses 4, 6, and 8-pole motors for three speeds, while the K45 uses 4 and 6-pole motors for two speeds, and the DK40 and DK45 both use 6 and 8-pole motors for two speeds. This combination of various machine sizes with two hub ratios, two structural types, and three speeds results in a total of 93 specifications for this series of fans. II. Application This series of fans is specifically designed to meet the needs of various non-metallic mines, including metallurgy, non-ferrous metals, gold, chemicals, building materials, and nuclear industries. They can be used as main fans and auxiliary fans, and can be installed on the surface or underground. They are suitable for multi-fan operation and are ideal station fans for multi-fan series and parallel multi-stage station ventilation systems. They are also applicable for ventilation and air exchange in large workshops, tunnels, civil defense projects, and other similar venues. III. Features The main features of the K series fans are as follows: 1. Utilizing twisted airfoil blades for high aerodynamic efficiency and significant energy-saving effects. 2. Diverse performance and a complete range of specifications, well-matching with various resistance and air volume types of ventilation networks, ensuring long-term high-efficiency operation. 3. Equipped with a flow stabilizing ring device, with a characteristic curve free of humps, eliminating surge risk, and ensuring safe and stable operation under any resistance condition, suitable for multi-fan operation. 4. Adopting a motor and impeller direct-drive structure for good overall stability, easy installation, and convenient maintenance with low local resistance. 5. Compact structure with good moisture resistance. The fan body is made of steel plate and shaped steel welding structure, with hollow blades made of steel plate material, high strength, and strong resistance to underground blasting shock waves. They can be installed on the surface and are also suitable for underground installation, especially suitable as station fans for multi-stage station ventilation systems. 6. Reversible reverse airflow with a reverse airflow rate greater than 60%, without the need to construct a reverse airflow channel. 7. Adjustable blade installation angles, allowing for real-time adjustment of the fan status according to changes in mine production. 8. Minimal civil engineering work, saving a significant amount of investment. 9. Low noise. IV. Diffuser When the K, DK series (now named FKZ, FKCDZ) mine energy-saving fans are used as main fans and station fans, a special diffuser should be used. For surface main fans, the diffuser can convert dynamic pressure to static pressure, reducing the loss of dynamic pressure at the outlet to achieve energy-saving purposes. For fans installed underground, the diffuser can reduce both the local resistance coefficient and the dynamic pressure value at the diffuser outlet, thereby significantly reducing the local resistance of the fan unit and saving ventilation energy consumption.