Pусский
In selection of mechanical seals, high pressure media such as synthetic chlorine water washing tower solution, ethylene unit demethanizer reflux liquid, ethylene oxide analysis tower still liquid and carbon dioxide absorption liquid hydrocracking raw materials, hydrorefining raw materials, etc. have their own specific standards.
This is determined by characteristics of these media. Characteristics of high pressure media are:
These characteristics determine requirements and selection criteria for mechanical seals as follows:
1.High pressure will cause end face specific pressure and POV value to increase, resulting in destruction of liquid film and increased wear.
2.When pressure is high,strength of the materials should be paid attention to to prevent the mechanical seal from being deformed and crushed, which is a seal failure.
These characteristics determine the requirements and selection criteria for mechanical seals as follows: 1. Ensuring the minimum allowable end face specific pressure,a larger balance coefficient β but not greater than 0.5 should be selected.
2.When medium pressure P > 15MPa, it is advisable to use tandem mechanical seal to gradually reduce sealing pressure of each stage.
3.Rotary face and stationary seat materials should be carbide-impregnated metal graphite or hard-to-hard materials, such as cemented carbide, ceramics, sprayed ceramics, etc.
4.Hydrostatic or hydrodynamic mechanical seals whose POV values can reach 270MPa.m/s should be adopted.
5.Cooling and lubrication should be strengthened.
6. It is recommended to use an O-ring with a minimum Shore hardness of 80 degrees, and use an isolation supporting ring to prevent it from being squeezed out.
This is determined by characteristics of these media. Characteristics of high pressure media are:
These characteristics determine requirements and selection criteria for mechanical seals as follows:
1.High pressure will cause end face specific pressure and POV value to increase, resulting in destruction of liquid film and increased wear.
2.When pressure is high,strength of the materials should be paid attention to to prevent the mechanical seal from being deformed and crushed, which is a seal failure.
These characteristics determine the requirements and selection criteria for mechanical seals as follows: 1. Ensuring the minimum allowable end face specific pressure,a larger balance coefficient β but not greater than 0.5 should be selected.
2.When medium pressure P > 15MPa, it is advisable to use tandem mechanical seal to gradually reduce sealing pressure of each stage.
3.Rotary face and stationary seat materials should be carbide-impregnated metal graphite or hard-to-hard materials, such as cemented carbide, ceramics, sprayed ceramics, etc.
4.Hydrostatic or hydrodynamic mechanical seals whose POV values can reach 270MPa.m/s should be adopted.
5.Cooling and lubrication should be strengthened.
6. It is recommended to use an O-ring with a minimum Shore hardness of 80 degrees, and use an isolation supporting ring to prevent it from being squeezed out.
