Carbon Seal Ring for Coal Mill(Long-term inventory ZGM series)


The carbon ring is made of carbon-graphite sealing material with special process and being immersed. According to analysis of the structure and performance of the carbon rings, the mechanical properties of the graphite material exceeded the domestic similar products, reaching the international advanced level with some indicators exceeded the corresponding international standards. They are comparable to similar foreign products on the material performance (including high lubrication, high temperature resistance, high strength and wear resistance) or processing precision. The longest lifetime reaches up to 10,000 hours in on-site test of some customers.

Our stock of carbon ring has:

ZGM Series: all models

MPS Series: Part Models

Some of HP models


Composition of carbon ring


  • High versatility property. Suitable for complex operating conditions and suitable for multi-unit pulverizer of the same series. For example, carbon ring for pulverizer ZGM113 series is also applicable to ZGM113-N series, ZGM113-G series, ZGM113-I series, ZGM113-II series, etc.
  • Easy installation. Carbon rings are usually marked with assembly order to ensure the sealing effect due to segmented installation is used for large sealing rings installation. The carbon sealing rings developed by our company is manufactured by advanced technology, which ensures that each segment is identical, so they can be assembled in any order, and ensures perfect sealing effect.
  • High temperature resistance. Due to the specific characteristics of carbon-graphite material and antimony immersion treatment, it can operate stably for a long time in an environment of 400 °C (or even 500°C to 600°C).
  • Better wear resistance and durability. Usually, the wear rate of carbon sealing ring is relatively high when the pulverized coal with high impurity content is encountered, which results in short lifetime. Under the condition of guaranteeing the sealing effect, the carbon sealing ring produced by our company can adapt to more diversified coal quality and have better lifetime.
  • Good stability. Products can operate steadily during the normal maintenance cycle of the power plant.


Carbon seal ring is installed in the annular groove of the sealing seat of the coal pulverizer, to isolate the hot air inside the coal pulverizer from the outside atmosphere. The inner circular surface of the ring is in contact with the drive shaft, and the outer circular surface is embedded in the groove of the transmission disk. In operation, no lubricant is required between the transmission shaft and the sealing ring, which requires that the self-lubricating property of the carbon ring must be very excellent. The internal hot air pressure of the coal mill is 10KPa and the temperature is ≤400°C. This requires that the carbon ring material must meet the temperature conditions of up to 400 °C and lower to -20 ° C, and have good mechanical strength in these conditions. Due to coal dust particles in operation environment, sometimes accompanied by water or water vapor, the reliability of the plant operation requires that the seal ring should have lifetime with more than 8,000 hours. This requires that the carbon ring material must have high strength and very good anti-wear properties, with certain mechanical strength, high processing accuracy and interchangeability.

Material Specifiacations

Relevant data indicators:

No. Index Data Note
1 Product Name Antimony impregnated carbon sealing ring
2 Material Number GX-T
3 Material Antimony impregnated graphite
4 Volume density 2.35g/cm3 Better than original factory standard
5 Shaw’s Intensity 90 Better than original factory standard
6 Compressive strength 180MPa Better than original factory standard
7 Working hours Guarantee a normal maintenance cycle

Antimony impregnated carbon sealing ring for ZGM113 series (part):

Standard figure number MG40.11.06.98 Chart number for standard product
Application site Drive plate base seal
Consumption 2 laps Original data, not modified by third party
Outer diameter/inner diameter Ф1932/Ф1900 Original data, not modified by third party
Width 16mm Original data, not modified by third party
Thickness 12mm Original data, not modified by third party
Accessories 20 sets of locating pin & spring 每圈必含


Due to the special process, each carbon sealing ring is exactly the same ensure disorderly arbitrary assembly.

Place sealing rings in any order, then install positioning pins and springs.

Packaging, storage and transportation

  • Packaging: Each sealing ring consists of multiple segments, the stacked multi-segments were outsourced PE film, tape wrapped and labeled with specification model label. The spring and positioning pins are placed together in a self-sealed bag. The sealing ring and accessories are place in carton box, which is surrounded by foam shock-proof, tape sealed and then reinforced by the packing belt.
  • Storage and transportation: Handle with care and pay attention to waterproof and oilproof.