20MG40.11.14 Resolving Leaks in the Loading Hydraulic Cylinder of Coal Mills

we address a common but critical issue in ZGM series medium-speed coal mills: loading hydraulic cylinder leakage. This problem not only compromises equipment cleanliness but also reduces the stability of the grinding force, directly leading to coarser pulverized coal, reduced output, and potentially unscheduled shutdowns.

When troubleshooting and addressing these issues, we must adhere to standard operating procedures and refer to the requirements for hydraulic system seal reliability outlined in DL/T 466-2017 (Selection Guidelines for Power Station Pulverizers and Pulverizing Systems) to ensure long-term system stability.

I.  Common Causes of Hydraulic Cylinder Leakage

Cylinder leakage typically stems from the following key factors:

• Seal Component Failure: This is the most prevalent cause. Prolonged exposure to high temperature and high pressure causes the O-rings, Y-rings, and other seals to age, deform, or wear, degrading their sealing performance.
• Moving Part Damage: Mechanical damage, such as scratches or nicks on the piston rod or the inner wall of the cylinder barrel, prevents the seals from forming an effective sealing surface, leading to leakage.
• Loose Connections or Poor Joint Sealing: Loose fittings on the high-pressure oil line connections to the cylinder body, or damaged/aged gaskets, frequently cause seepage when system pressure fluctuates.
• Accumulator Pressure Abnormality: Insufficient nitrogen pre-charge pressure or internal bladder rupture in the accumulator can lead to severe pressure fluctuations in the hydraulic system, accelerating the fatigue and failure of the seals.

II. Systematic Troubleshooting and Repair Procedure

1. Shutdown Inspection: First, perform a safe shutdown and depressurization of the system. Visually inspect the leak location to determine if it originates from the piston rod end, the cylinder body joint face, or the piping connectors.
2. Tightening and Cleaning: Check all pipe connection threads for tightness. Clean the joints and replace any aged gaskets or seals.
3. Cylinder Diagnosis: If the issue points to a seal problem, disassemble the cylinder. Focus on inspecting the condition of the seals and the surface finish (smoothness) of the cylinder barrel and piston rod. Minor scratches can be repaired by grinding; severe damage requires component replacement.
4. Auxiliary System Check: Use professional tools to check the nitrogen pressure in the accumulator. Ensure it is maintained at the design standard value (approximately 4 MPa) to stabilize system pressure.

III.  High-Efficiency Solution: Utilizing the 20MG40.11.14 Loading Cylinder

To permanently eliminate leakage issues, we recommend using the genuine 20MG40.11.14 Loading Hydraulic Cylinder. This model is specifically designed for ZGM123 series pulverizers, featuring a large bore, long stroke, and high-pressure bearing capacity, perfectly matching the original hydraulic system.

We utilize imported, high-temperature resistant sealing materials and precision honing technology to ensure the cylinder remains leak-free under sustained high-pressure operation, significantly boosting system reliability and extending maintenance cycles.

We provide a full range of spare parts for the ZGM series, including:

• Coupling (20MG40.11.02) (Ensures stable transmission)
• Scraper Blade (20MG40.11.07.01.96) (For efficient reject discharge)
• Roller Core (20MG60.11.09.94J) and Mill Roller End Cover (20MG40.11.09.93J) (Ensure optimal roller operation)
• Hinge Shaft Assembly (20MG40.11.11-A) and Medium-Speed Mill Hinge Shaft Clip Plate (20MG40.11.11.03)
• Medium-Speed Mill Ceramic Liner (20MG23.11.08.96JTC-JK) (High wear resistance)
• And common spares like roller breathers, fastening bolts, and filter screens.
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HKZX-2025-10-31