Mechanical seals have any common sense

Seal selection, working conditions must be considered to select the appropriate form of seals and materials, installation structure.
Need to consider working conditions generally include: temperature, pressure, media. Others also need to combine the characteristics of the device itself to consider the selection.
About the temperature, such as NBR material Operating temperature range is generally -40 ~ +120 ℃. It is necessary to consider beyond 120 ℃ FKM, and even the PTFE material. Low temperatures are relatively rare, in general the -20 ~ -40 ℃ in case you want to consider the use of cold NBR, NBR material generally will result in a low temperature environment material hardens, resulting in leakage, such as railway locomotives in the northern winter was often such problems.
As pressure, the impact to be used in the form of a high security bolt seals. Generally, low-pressure and medium pressure use rubber or PU seals will not be much problem. But to be considered a shock pressure problems, such as construction machinery startup, shut down when its impact is much larger than the normal working pressure of the pressure, it will often use pressure up 70MPA impact resistance to collapse or SPGW do the main gap HBY cable seals. PTFE seal combination is also commonly a choice.
Media with a relatively simple. Just need some special attention to small problems, such as metallurgical industry, often using a water tank - glycol and phosphate ester hydraulic oil. Although sometimes working temperature is not high, but still have to be very careful selection of materials, hydraulic oil when the latter still have to use FKM.