ZGM123 Pulverizer Roller Sealing Air Duct: Function and Troubleshooting Guide

We delve into a small but crucial component in the ZGM123 series coal pulverizer: the Roller Sealing Air Duct. Some might ask, "It's just a pipe—how is it related to the roller’s operation?" In reality, this duct acts as the roller's "protective shield" and "mini air conditioner." Without it, or if it malfunctions, the roller could "strike" (fail) within 1-2 months. We will thoroughly explain the core value of the ZGM123 roller sealing air duct in four steps: its function, its working mechanism, failure symptoms, and selection/maintenance tips.

I. Understanding the Necessity: Why ZGM123 Rollers Depend on the Sealing Air Duct

Before discussing the duct, we must first understand the harsh operating environment of the ZGM123 roller. The roller is the component that crushes raw coal against the grinding ring. Its working area is saturated with fine coal powder (80-120 mesh), which is hard and sharp, along with high-temperature dust generated by the grinding process.

Coal Dust Intrusion: If coal dust invades, it acts like sandpaper, damaging the oil seal lips and contaminating the lubricating oil. The bearing could seize due to lack of lubrication within 3-5 days.

• Overheating: If the oil temperature exceeds ,the lubricant thins out and loses its effectiveness, leading to bearing overheating and wear within one week.

This is where the ZGM123 Roller Sealing Air Duct comes into play. Its core mission is to create a "safety zone" for the roller's "heart"—one that blocks coal dust and aids in cooling. This vital function makes it a critical spare part for the pulverizer.

II. Working Mechanism: How the ZGM123 Sealing Air Duct Protects the Roller (Positive Pressure Sealing Principle)

The operation of the ZGM123 roller sealing air duct follows a "three-step" process, centrally relying on Positive Pressure Sealing Technology

Step 1: "Delivering Clean Air" - Precise Transportation of Filtered Air

First, the pulverizer's sealing fan blows clean air,  into the upper "annular air duct." It then passes through the three dedicated ZGM123 roller sealing air ducts, delivered precisely to the roller frame of each grinding roller.

A key design feature here is the use of a Spherical Plain Bearing (GCr15 bearing steel is a suitable match) at the connection point between the duct and the annular duct.

Step 2: "Building the Barrier" - Positive Pressure Air Wall Blocks Coal Dust

The clean air enters the roller frame and flows to the outer side of the oil seal and the "air sealing ring," creating a continuous annular sealing belt (the "air wall"). the positive pressure differential actively "pushes back" the coal dust, completely blocking its path of intrusion. This is the most critical protective function of the roller sealing air duct and is key to preventing oil seal wear.

Step 3: "Cooling Down and Stabilizing Pressure" - Extending Roller Life

In addition to blocking coal dust, the sealing air duct provides two auxiliary functions:

1. Auxiliary Heat Dissipation
2. Pressure Stabilization
3. III. Troubleshooting Guide: Symptoms of ZGM123 Sealing Air Duct Failure

Failure of the roller sealing air duct is a common cause of ZGM123 pulverizer downtime. The following three scenarios require immediate attention:

1. Duct Damage/Flange Looseness:  Coal dust directly invades, manifesting as "oil seal leakage and abnormal bearing noise." The roller could seize within 2-3 days.
2. Spherical Plain Bearing Wear: Air leaks at the connection point, and bearing seizing can snap the duct. Symptoms include "duct vibration and significant fluctuation in sealing air pressure." Immediate replacement of the bearing spare part is required.
3. Contaminated Air Source (Filter Screen Failure): Dust is actively delivered into the roller, essentially "introducing impurities." This is indicated by "blackened lubricating oil and accelerated bearing wear." The filter screen and air duct must be inspected simultaneously.

IV. Huakaishengrui ZGM Series Sealing Air Duct Case Studies (Including Selection Parameters)

Huakaishengrui specializes in spare parts for power plant pulverizers and can provide sealing air duct solutions for the entire ZGM series, including ZGM123, ZGM113G, and ZGM95G. Here are typical case examples:

V. Summary: ZGM123 Roller Sealing Air Duct – The Roller’s "Life-Saving Spare Part"

The ZGM123 pulverizer roller sealing air duct may seem minor, but it is the roller's "exclusive protection channel."

HKZX-2025-10-23