Introduction to Graphite Rings

Graphite rings are sealing rings made from high-purity graphite material, offering excellent self-lubrication, high-temperature resistance, and chemical stability. They are an ideal sealing solution for high-temperature and high-pressure working conditions.

 

 Core Characteristics

Characteristic	Description	Advantages
Excellent High-Temperature Resistance	Can be used up to 3000°C in an inert atmosphere	Suitable for extreme high-temperature conditions
Outstanding Self-Lubrication	Low friction coefficient (0.04-0.12)	No external lubrication required, reducing maintenance
Exceptional Chemical Stability	Resistant to most acids, alkalis, and organic solvents	Suitable for corrosive media
Good Thermal Shock Resistance	Withstands rapid temperature changes	Ideal for thermal cycling conditions
Compressibility and Resilience	Certain compression and rebound capabilities	Adapts to flange unevenness

 

 

 Material Types

Type	Characteristics	Operating Temperature (°C)	Applications
Flexible Graphite	Good compressibility, excellent sealing performance	-200~450 (in air)	General sealing applications
High-Strength Graphite	High mechanical strength, good wear resistance	-200~500	High-speed and high-pressure conditions
Impregnated Graphite	Performance improved through impregnation	-200~600	Special working conditions
Nuclear-Grade Graphite	High purity, low neutron absorption cross-section	-200~1000	Nuclear industry applications

Performance Parameters Table

Performance  Indicator	Flexible Graphite	High-Strength Graphite	Impregnated Graphite	Test Standard
Density (g/cm3)	1.0~1.3	1.6~1.9	1.8~2.1	ASTM C838
Compressive Strength (MPa)	40~80	60~120	80~150	ASTM C695
Thermal Conductivity (W/m·K)	50~150	80~160	60~120	ASTM C714
Friction Coefficient	0.08~0.12	0.06~0.10	0.06~0.10	ASTM D2714
Oxidation Start Temperature (°C)	400	450	500	ASTM D7542

 

Structural Forms

1. Basic Graphite Rings:

   · Pure graphite material

   · Suitable for medium-to-low pressure static sealing

2. Reinforced Graphite Rings:

   · Enhanced with metal or ceramics

   · Improved mechanical strength

3. Composite Graphite Rings:

   · Combined with metal components

   · Suitable for high-pressure dynamic sealing

4. Cut Types:

   · Straight cut

   · Angled cut

   · Overlap cut

 

 Selection Guide

1. Working Condition Analysis:

   · Temperature and pressure range

   · Media characteristics

   · Motion type (static/dynamic)

2. Material Selection:

   · Use impregnated graphite for oxidizing environments

   · Use high-strength graphite for high-pressure conditions

   · Use nuclear-grade graphite for the nuclear industry

3. Size Determination:

   · Based on sealing cavity dimensions

   · Consider thermal expansion factors

   · Reserve appropriate compression amount

 

Installation and Usage Requirements

1. Pre-Installation Preparation:

   · Check sealing surface finish (Ra ≤ 1.6 μm)

   · Remove impurities from sealing surfaces

   · Measure cavity dimensions

2. Installation Precautions:

   · Use dedicated installation tools

   · Avoid rough handling

   · Apply tightening force evenly

3. Usage and Maintenance:

   · Regularly check compression amount

   · Monitor leakage situation

   · Avoid overheating

 

Application Fields

1. Petrochemical Industry: Reactors, compressors, valve seals

2. Power Industry: Steam turbines, gas turbine seals

3. Nuclear Industry: Nuclear reactor sealing systems

4. Aerospace: Engine sealing components

5. General Machinery: Pumps, mixer seals

 

Special Treatment Processes

1. Anti-Oxidation Treatment:

   · Phosphoric acid impregnation

   · Ceramic coating

   · Metal plating

2. Reinforcement Treatment:

   · Carbon fiber reinforcement

   · Metal wire reinforcement

   · Ceramic particle reinforcement

3. Impregnation Treatment:

   · Synthetic resin impregnation

   · Metal impregnation

   · Inorganic salt impregnation

 

Graphite rings, with their unique high-temperature resistance, self-lubrication, and chemical stability, are the preferred material for high-temperature sealing applications. Through proper selection, correct installation, and appropriate maintenance, graphite rings can provide reliable sealing performance under extreme conditions. Understanding the characteristics and application ranges of different graphite materials is key to ensuring sealing effectiveness.