Spring Plate  SAF26.6-17-2 :Critical Component Translation: Induced Draft Fan Hydraulic Mechanism

In large-scale thermal power generating units, the stable operation of the adjustable-blade axial induced draft fan (IDF) relies not only on blade adjustment precision but also on a seemingly minor yet critically important component within the transmission system: the IDF Hydraulic Mechanism Spring Plate, SAF26.6-17-2. This part functions as both a "flexible buffer and torque transmitter" between the hydraulic actuator and the coupling.

Primary Function of the SAF26.6-17-2 Spring Plate

The spring plate SAF26.6-17-2 is installed within the diaphragm coupling assembly located between the fan's main shaft and the intermediate shaft. It primarily serves three key functions:

1. Torque Transmission: It transmits the adjustment torque output by the servo motor via the hydraulic mechanism to drive the inlet guide vanes (IGVs) to move synchronously.

2. Flexible Buffering: It absorbs minute axial and angular displacements caused by thermal expansion, foundation settling, or minor misalignment errors, preventing rigid impact.

3. Vibration Damping: It damps high-frequency vibration, preventing fatigue failure.

Failure (such as deformation, cracking, or fatigue) of the spring plate will directly lead to IGV adjustment sticking, unsynchronized movement, or even trigger a catastrophic fan stall or surge condition.

Connection Between the Spring Plate and the Coupling

In the IDF structure, the coupling utilized is a flexible disc coupling with a spring plate design. The spring plate acts as the core elastic element, clamped and secured by high-strength bolts between the two end flanges of the coupling.

• Its installation precision directly influences the concentricity of the entire rotor system (specification requirement $\le 0.10 \text{mm}$).

• Uneven stiffness or localized damage to the spring plate can cause dynamic imbalance in the coupling, leading to excessive bearing vibration, oil film damage, and in severe cases, triggering an unscheduled shutdown.

Special Note on Installation: When shrink-fitting the coupling, direct flame heating of the spring plate is strictly prohibited. This would anneal and soften the material, causing it to lose its elastic properties. Therefore, replacement parts must be Original Equipment Specification (OES) parts that perfectly match the required material, thickness, and heat treatment process.

Product Recommendation

We highly recommend our company, Huakai Shengrui’s, IDF Hydraulic Mechanism Spring Plate, SAF26.6-17-2.

• Our product is precision stamped from high-strength alloy steel (35CrMoA), followed by vacuum heat treatment and surface shot peening for reinforcement.

• This process boosts the fatigue life by over 30%.

• All parts undergo 100% magnetic particle inspection (MPI) and dynamic balance testing.

In summary: Don't underestimate this "steel plate"; it is the "articular cartilage" for the smooth operation of the IDF adjustment system. Regular inspection and timely replacement of deteriorated spring plates are crucial steps in preventing adjustment failures. Choosing Huakai Shengrui means choosing reliability and peace of mind!

HKZX-2025-12-09