Application characteristics of pneumatic telescopic mechanical seal

 

Advantages

1. Reliable sealing during long-period operation, the sealing state is very stable and the leakage is very small. According to rough statistics, the leakage is generally only 1/100 of soft filling sealed;

2. The service life can generally reach 1 to 2 years or longer in oil and water Media, and can usually reach more than half a year in chemical media;

3. Friction power consumption the friction power of small mechanical seal is only 10% ~ 50% of that of soft filling seal;

4. The shaft or sleeve is basically not worn;

5. The maintenance cycle can be automatically compensated after the end face is worn. In general, regular maintenance is not required;

6. Good vibration resistance is insensitive to the vibration, deflection of the rotating shaft and the deflection of the shaft to seal cage;

7. Wide application range mechanical seals can be used for sealing of low temperature, high temperature, vacuum, high pressure, different rotating speeds, as well as various corrosive media and abrasive media.

8. For the "zero leakage" needs of many factories, the packing seal cannot meet this requirement; The fundamental adaptation range is wide and the randomness is greater, but for the factory, frequent replacement or maintenance will cause great losses to the factory. It can be used in telescopic mast.

 

Disadvantages

1. Complex structure and high requirements for manufacturing and processing;

2. Installation and replacement are troublesome, and workers are required to have a certain level of installation technology;

3. It is difficult to deal with accidental accidents;

4. High one-time investment.

There are two cases of vacuum device sealing. One is that the sealing element separates a container filled with liquid medium from the external vacuum space. In this case, the main function of the seal is to prevent the liquid medium from leaking into the vacuum space. Another case is that the seal separates the vacuum inner cavity from the outer cavity, and its function is to maintain the required vacuum degree. This situation is more complicated, because even if the surrounding gas medium leaks into the vacuum chamber slightly, the vacuum degree will be reduced. If corrosive gas leaks, the vacuum equipment may be damaged. In many cases, vacuum degree and cleanliness of vacuum space have a decisive influence on the quality of various technological processes under vacuum conditions. The mechanical seal used by vacuum devices has no special structure. For the first case mentioned above, the metal bellows type single-end mechanical seal with good air tightness is usually adopted. In the second case, double side mechanical seal is used. If single end face seal is used, the problem that the sealing end face cannot be lubricated is bound to exist.

Generally, it is difficult for people to distinguish between mechanical sealing pieces and hydraulic sealing parts, and they often think that they are the same object.

I. Definitions of mechanical sealing pieces and hydraulic sealing parts:

Mechanical sealing pieces is one of the precise and complex mechanical basic components, and is the key components of various pumps, reaction synthesis kettle, turbine compressor, submersible motor and other equipment. Its sealing performance and service life depend on many factors, such as selection, accuracy of the machine, correct installation and use, etc.

Hydroseal there are pressure requirements, which require a certain smoothness of the joint surface. More than potted component use rubber to achieve the sealing effect through the local deformation of the seal.

II. Classification of mechanical sealing pieces and hydraulic sealing parts

Mechanical sealing pieces model: containerized seal series, light mechanical seal series, heavy mechanical seal series, etc.

Hydraulic sealing parts: Lip seal, V-shaped seal ring, U-shaped seal ring, Y-shaped seal ring, YX-shaped seal ring and hydraulic cylinder commonly used combination seals are mainly lace ring, grid ring and sitefeng.

3. Select seals

When purchasing seals for maintenance, most users will buy them according to the size and color of the samples, which will only increase the difficulty of purchasing and may not be able to select suitable products. The following procedures are recommended to improve the accuracy of purchasing seals:

1. Movement direction-first determine the movement direction of the position where the seal is located, such as reciprocating, rotating, spiral or fixed.

2. Key point of sealing-for example, the pull rod seal that determines the activity point is in the inner diameter or the activity point is piston seal of the outer diameter.

3. Temperature grade-check the instructions of the original machinery or evaluate the working temperature according to the actual working environment to decide the materials to be used. For more information about temperature levels, see the following precautions for production users.

4. Size-most users will choose the old samples used, but the original size of the seal will be greatly affected by factors such as temperature, pressure and wear after using for a period of time, according to the sample selection can only be used as a reference, a better way is to measure the size of the metal groove where the seal is located, and the accuracy will be higher.

5. Pressure Level-consult relevant data from the instructions of the original machine, or infer the working pressure level by observing the hardness and structure of the original seal, for more information about the pressure level, see the following precautions for production users.