A seal, often known as a mechanical seal, can be described as a kind of device which helps join systems or mechanisms together. In doing so, a seal is often intended to prevent leakage, contain pressure, or keep out various kinds of contamination. It is important to note that there are various different kinds of seals, however they can be divided into roughly to categories: sealants and gaskets. Sealant work by adhesion while gaskets work by compression. It is also important to note that seals vary in strength and effectiveness. Furthermore, within these two basic categories there are many other kinds of seals, such as peek seals, spring energized seals, rubber o rings, etc.
Sometimes, seals are required to work in extreme conditions, like extreme temperature fluctuations or extreme pressure. If you need a seal to perform under high pressure you will want to look into high pressure seals while if you need a seal to preform under high temperatures you will want to look into high temperature seals, such as high temperature oil seals. Oil is a highly corrosive material, therefore if your seal will be containing oil it is advantageous to look into high temperature oil seals. Find more.