EN CN
Home / Services / Pump Encyclopedia / Pump Technique / Characteristics of mechanical seal material of corrosive-resistant fluorine chemical centrifugal pump bellows

Characteristics of mechanical seal material of corrosive-resistant fluorine chemical centrifugal pump bellows

04 Jul 2021Email

Corrosion-resistant fluorine chemical centrifugal pump mechanical seal is commonly used in the form of bellows mechanical seal, but few people know what material combination it has, what kind of material is matched under what industrial and mining conditions, and today Zoomlion Pump Industry will talk to you about resistance The material characteristics of the corrosive lined fluorine chemical centrifugal pump bellows mechanical seal.

Corrosion-resistant fluorine chemical centrifugal pump

Corrosion-resistant fluorine chemical pump mechanical seals are strictly regulated by the "China Machinery Industry Standard: Mechanical Seals for Pumps" for its mechanical seal structure, installation dimensions, material matching, physical and chemical properties, etc. Most of the acid-resistant centrifugal pumps are corrosion-resistant. Centrifugal pumps, fluoroplastic pumps, and fluorine chemical lined centrifugal pumps all use bellows mechanical seals. The mechanical seals only use metal material (304 stainless steel) for pre-compression springs and split-half compression rings. The rest of the matrix is ​​made of ultra-strong corrosion-resistant pure Production of materials such as PTFE, filled PTFE, 99% purity ceramics, SiC silicon carbide, etc. The rotating ring assembly is pre-compressed with an external spring, and a built-in PTFE bellows auxiliary compensation element is used to realize the working conditions that the medium cannot The contact of springs and other metal parts greatly improves the corrosion resistance of the bellows mechanical seal. It is not only suitable for strong corrosive media such as strong hydrochloric acid, strong sulfuric acid, and strong nitric acid, but also has better corrosion resistance to diluted hydrochloric acid, sulfuric acid, nitric acid and other corrosion processes. Slow but highly corrosive working conditions have good corrosion resistance.

 

Features of mechanical seal of corrosion-resistant fluorine chemical centrifugal pump:

The bellows mechanical seal is an external mechanical seal. Among them, F4 is a ceramic mechanical seal which is generally suitable for transportation and has strong corrosiveness and volatility. SIC mechanical seals made of SIC are wear-resistant and high-temperature resistant, and can transport abrasive and corrosive liquids containing particles and crystals. The moving ring and the static ring, and the static ring gland installed on the sealing shaft are characterized in that the static ring is embedded in the inner hole of the static ring gland, the static ring gland is provided with a liquid injection hole, and the static ring is opened with liquid injection The radial through hole communicating with the hole communicates with the gap between the static ring and the sealing shaft, and the inner end surface of the static ring is in contact with the sealing ring on the sealing shaft. The liquid in the pump cavity is blocked by the sealing liquid and cannot flow to the static ring and the moving ring. The liquid in the machine cannot overflow, so there is no environmental pollution; moisture exists between the contact surface of the moving ring and the static ring. It produces lubrication, reduces the friction between the contact surfaces, and because the end surface area of ​​the moving ring is larger than the end surface area of ​​the static ring, the contact surface of the static ring can be evenly worn, and the service life of the static ring and the moving ring is prolonged. The shaft seal device is a single-end face multi-spring bellows externally mounted mechanical seal, using non-cooling water to adjust the end face sealing technology, the friction pair material usually includes silicon carbide-filled with PTFE, carbon fiber-silicon carbide, and the mechanical seal can also be selected as a hard seal Mechanically sealed, the main liquids conveyed include fine particles, crystals, and various acid-base corrosive liquids. Silicon carbide mechanical seal ring has the characteristics of light weight, low thermal expansion coefficient, high hardness, good high temperature strength, good size at extremely high temperatures, strong corrosion resistance, high elastic modulus, and long service life. It can be used in many complicated working conditions such as radioactivity, corrosiveness, highly toxic, flammable, explosive, high temperature and so on. Suitable for use in petroleum and chemical pumps.


Features of mechanical seal material of corrosion-resistant fluorine chemical centrifugal pump:

1. The materials for sealing friction include: graphite, ceramic, hardfacing hard alloy, tungsten carbide alloy, SiC, filled with PTFE, etc.:

(1) Graphite: Advantages: Good corrosion resistance and self-lubrication, low friction coefficient, good thermal shock resistance and easy processing. The disadvantage is that the mechanical strength is low and there are pores. These two shortcomings of graphite can be improved by impregnation and carburization. Impregnated graphite can be divided into two types: resin impregnated and impregnated metal. The resin-impregnated graphite has good corrosion resistance, but it is not resistant to high temperature (temperature resistance is about 170-200℃); the impregnated metal graphite has good temperature resistance (the high temperature resistance of immersed bronze, aluminum, lead, etc. can reach 400-500℃), but it is corrosion resistant Poor sex. Graphite is the most widely used non-metallic material, used as a moving ring for medium and low speed mechanical seals and a static ring for high speed mechanical seals.

(2) Ceramics: The advantages are good corrosion resistance, high hardness, good wear resistance, but the disadvantages are brittleness and high hardness that are difficult to process. Most applications are alumina ceramics and cermets. Ceramics are mostly used in corrosive media, medium and low speed occasions.

(3) Hard alloy surfacing: Hard alloy surfacing on the sealing surface of carbon steel, chromium steel and chromium-nickel steel has the advantages of high hardness, good wear resistance, good temperature resistance (below 500°C), and corrosion resistance Or the cavitation is good, the disadvantage is that it is easy to produce pores, slag inclusions and uneven surface hardness.

(4) Tungsten carbide alloy: Metal carbides with high hardness and high melting point, such as tungsten carbide and titanium carbide, are pressed and sintered by powder metallurgy with a binder. The advantage is that the hardness and strength are very high. Excellent wear resistance, general high temperature resistance, general acid corrosion resistance (inferior to silicon carbide), excellent alkali resistance (stronger than silicon carbide), and low linear expansion coefficient. The disadvantage is that it is brittle and difficult to process.

2. Material of mechanical sealing ring: The requirements for auxiliary sealing materials are good elasticity, low friction coefficient, good wear resistance, heat resistance and low temperature resistance, resistance to medium corrosion, dissolution and aging, etc. In addition, it is also required to be compressed and long-term The residual deformation is good during use. Commonly used auxiliary seal ring materials are rubber and polytetrafluoroethylene.

(1) Polytetrafluoroethylene: The advantages are chemical stability, oil resistance, dissolution resistance, moisture resistance, low friction coefficient, suitable for various corrosive media, and the disadvantage is that it is less elastic than rubber and prone to permanent deformation.

(2) Rubber: It has good elasticity, cushioning, vibration absorption, heat resistance and corrosion resistance. The rubber sealing ring has a good sealing effect and is the most widely used. Commonly used rubbers include silicone rubber, nitrile rubber, chloroprene rubber and fluorine rubber.

(3) Fluorine rubber: It has excellent high temperature resistance and corrosion resistance. It is currently the most widely used auxiliary sealing ring material for mechanical seals.

(4) Ethylene-propylene rubber: It has excellent alkali resistance and is mainly used in alumina working conditions.

(5) Perfluoroether: The material with the best chemical resistance, high and low temperature resistance, and aging resistance found so far, but it is expensive. (It is only recommended for users to use in strong corrosive conditions above 300℃)

3. Spring material: good elasticity and corrosion resistance. Commonly used spring materials are stainless spring steel (1Cr18Ni9Ti, etc.), chromium steel (3Cr13, 4Cr13, etc.), carbon cable spring steel (60si2Mn, etc.) and phosphor bronze.

Related Pump Knowledge
More Pump Knowledge
25 Mar 2024
Large displacement pump type           Large displacement pump, as the name suggests, is a pump with a very large flow, and ...
Read more
18 Mar 2024
         Coal mine drainage pump is one of the indispensable mechanical equipment in coal mine, its role is reflected in many...
Read more
07 Mar 2024
        The working principle of the multistage centrifugal pump is: relying on the high-speed rotating impeller, the liquid obtai...
Read more
29 Feb 2024
          Centrifugal pump is a common and important type of pump, which is widely used. However, in the process of using centrifugal pumps, irrigatio...
Read more
Related Products
More
Split Case Pump
Split Case Pump
  • Capacity:60-33005m³/h
  • Head:0.95-30.2bar
  • Price:$2200-215000
Double Suction Pump
Double Suction Pump
  • Capacity:60-33005m³/h
  • Head:0.95-30.2bar
  • Price:$2200-215000
Single Stage Chemical Pump
Single Stage Chemical Pump
  • Capacity:5.5-2600m³/h
  • Head:1.6-25bar
  • Price:$4300-37000
End Suction Chemical Pump
End Suction Chemical Pump
  • Capacity:5.5~400m³/h
  • Head:0.42-12.5bar
  • Price:$560-9800
Need More Information?
Contact us for more details about our pump, solutions and services.
Contact ZB
Tel
0086 731 88192011
Leave a message
Name*
Tel
Email*
Area
Products
Split Case Pump
Metallurgy
Mining Industry
Urban Water Supply
Petrochemical
Light Industry
Electricity
Chemical Industry
Farmland Irrigation
Other
Provide your comments and questions.