Mechanical Seal Manufacturers: Introducing Two Common Choices for Mechanical Seals Mechanical Seals

1. Selection of P, V, T operating parameters

Here p refers to the working pressure of the medium at the sealing chamber. According to the value of p, enterprises can conduct preliminary analysis to determine whether they need to choose a balanced structural design and develop different levels of balance. For the environment medium with high viscosity and good lubricity, p≤0.8MPa, or medium with low viscosity and poor lubricity, p≤At 0.5MPa, we usually choose an unbalanced structure. When the p value exceeds the above research range, students should consider choosing a balanced structure. When p> 15MPa, it is difficult to meet the sealing technical requirements for the general single-end balanced structure. At this time, the series multi-end seal can be selected.

theυRefers to the average circular motion speed of a diameter of the sealing surface, according toυThe size of the value can determine whether the elastic working elements of the enterprise rotate with the axis, that is, different spring rotating or spring static structures are used.υ< 20 ~ 30m/s can use the spring rotating type, under the condition of higher speed development, because the unbalanced data quality of the rotating parts is easy to cause strong vibration of the students, the best way to use this spring static structure. if p andυWhen the values ​​are high, we can consider that we choose a hydrodynamic structure.

Mechanical seal manufacturers

t refers to the temperature of the medium in the sealing cavity. According to the size of t, the material of an auxiliary sealing ring, the influence of the sealing working surface on cooling methods and methods, and its important auxiliary management system can be determined. The temperature t is in the range of 0 ~ 80 ℃, and the auxiliary sealing ring usually uses nitrile rubber O-ring; -50 ℃≤t<150°C, according to the corrosiveness of different media, you can choose fluorine rubber, silicone rubber or polytetrafluoroethylene molding packing seal ring: temperature<-50 or t≥At 150°C, rubber and PTFE will produce a kind of low-temperature embrittlement or high-temperature environment aging. At this time, enterprises can use some metal bellows structures. When the turbidity of the medium is significantly higher than 80°C, the application in the sealing field is usually considered as high temperature. At this time, the teacher must take timely measures to establish corresponding cooling technology.

2. Select according to the characteristics of the medium

For less corrosive media, the internal mechanical seal is usually selected, and the stress state of the end face and the leakage direction of the medium are more reasonable than the external mechanical seal. For highly corrosive media, due to the difficulty in selecting spring materials, external or PTFE mechanical seals can be used, but generally only suitable for p≤0.2 ー 0.3 mpa range.

It is easy to crystallize, easy to solidify the medium and high viscosity, and the rotation should be a large spring structure. Because small springs tend to clog solids, high-viscosity liquids can be prevented for compensation of small axial movements of the spring.

Inflammable, explosive, and toxic medium, in order to ensure that the working medium does not leak out, it should be possible to use double-ended surfaces with sealing fluid (isolating fluid) for the structure.

According to the above-mentioned research work, the selected structural problems of parameters and medium properties can not only be used as a preliminary solution for a student, but it can be finally determined that the characteristics of the host machine and some special educational requirements for sealing must also be considered. For example, the sealing life of a rocket engine is only a few minutes, but it is required to be absolutely leak-free in a short period of time. The main engine on a ship is sometimes to obtain a more effective space, and it often needs to put forward very strict requirements for the size and installation position of the seal. Another example is the drainage pump on a submarine. During the process of sinking and floating of the submarine, the pressure changes continuously. Very big wait. In these cases, the technical standard architecture cannot be selected conventionally, but a special environment design must be made for specific working conditions, and some necessary auxiliary management measures must also be taken.