20MG60.11.12.06.02 ZGM Medium-speed Pulverizer Upper Seal Sleeve

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In the sealing and protection system of the ZGM Medium-speed Pulverizer, the Upper Seal Sleeve (Part No. 20MG60.11.12.06.02) is a critical component located in the upper grinding zone. Its performance directly determines the protection effectiveness of the transmission system and the overall operational stability of the equipment.

By forming a labyrinth seal structure with rotating components such as the mill bowl hub, this spare part effectively blocks coal dust and hot air from infiltrating the transmission system. It simultaneously functions as wear protection and component positioning, making it a core focus during pulverizer maintenance and overhauls.

I. Product Description

The Upper Seal Sleeve 20MG60.11.12.06.02 is a specialized seal designed for the ZGM series. It is installed at the top of the grinding area to form a primary sealing pair with the bowl hub.

During operation, the grinding zone is subjected to high-temperature hot air and high-velocity coal dust streams. If the seal fails, infiltration can lead to accelerated wear of transmission components—such as the Coupling Pin (20MG40.11.02.J) and Rigid Coupling Elastic Ring (MG40.11.02.97)—and may even contaminate the lubrication system. Therefore, the sealing integrity and wear resistance of this sleeve are paramount.

Material & Compatibility:

Material: Manufactured from Q235A Carbon Structural Steel (strictly following GB/T 700-2006).
Performance: Yield strength 235MPa, offering excellent weldability and cost-efficiency.
System Integration: It works in synergy with the Oil Seal Support Ring (20MG30.11.09.83) and Roller Oil Seal (20MG20.11.09.92J). It also provides auxiliary positioning for the Scraper (20MG33.11.07) and Scraper (20MG40.11.07.01.96).

II. Technical Features and Advantages

Parameter Category	Specification / Indicator	Remarks
Product Model	Upper Seal Sleeve 20MG60.11.12.06.02	Specific to ZGM Series
Material Standard	Q235A (GB/T 700-2006)	Carbon steel with excellent weldability
Mechanical Property	Yield Strength 235MPa	Meets load requirements of grinding zone
Seal Structure	Labyrinth Seal	Multiple clearances with the bowl hub
Core Functions	Sealing, Wear Resistance, Positioning	Blocks dust/heat; serves as mounting base
Compatible Parts	Oil Seal Support Ring, Roller Oil Seal	Forms a multi-layer sealing system
Maintenance Cycle	Synchronized with mid-overhaul (3k-4k hrs)	Check for wear, deformation, and clearance

1. Material and Durability

The use of Q235A steel ensures the sleeve can withstand the pressure and mechanical loads of the grinding zone. To counter the erosion caused by high-speed coal dust, the surface undergoes hardening treatment. Its superior weldability allows for on-site repair and build-up welding during maintenance, significantly reducing replacement costs.

2. Structural Design

The labyrinth design utilizes airflow damping principles to block dust, which is far more effective than standard flat seals. Furthermore, it acts as the installation benchmark for the Shaft Sleeve (20MG42.11.09), ensuring coaxiality and preventing vibration.

3. System Synergy

The interface is precision-engineered to be compatible with the Roller Carriage (20MG40.66) and Proportional Relief Valve (20MG00.21.14). It ensures that the loading adjustment and transmission systems operate without interference.

III. Application Scenarios

1. Routine Maintenance

Per the ZGM Medium-speed Roller Pulverizer Maintenance Manual, a patrol inspection of the upper sealing components should occur every 1,000 operating hours.

Inspection Focus: Check for coal dust accumulation, surface scratches, and deformation.
Clearance Limits: If the gap between the sleeve and the hub exceeds 0.5mm, adjustment or repair is required.

2. Disassembly & Overhaul

During major maintenance or when vibration/oil contamination is detected, the grinding zone is disassembled.

The Upper Seal Sleeve must be checked for cracks or excessive wear.
When replacing the Shaft Sleeve (20MG42.11.09), the Upper Seal Sleeve serves as the reference point for alignment to ensure stable operation post-assembly.

3. Emergency Fault Handling

In the event of a Proportional Relief Valve (20MG00.21.14) failure (causing abnormal loading pressure) or scraper wear, the Upper Seal Sleeve may experience accelerated erosion. If coal dust enters the transmission, it will damage the coupling pins. Immediate shutdown and replacement of the seal sleeve are necessary to prevent further damage to the lubrication and drive systems.