According to the installation position of the static ring, it can be divided into internal and external mechanical seals. The mechanical seal with the static ring installed on the inner side of the sealing gland (or the part equivalent to the sealing gland) (that is, the side facing the working chamber of the host) is called the built-in mechanical seal; conversely, when the static ring is installed on the outside of the sealing gland, it is called External mechanical seal.
Built-in mechanical seal: refers to the mechanical seal installed in the sealed cavity;
External mechanical seal: refers to the mechanical seal installed outside the sealed cavity.
Since the built-in mechanical seal has a good stress condition, the specific pressure increases with the increase of medium pressure, and the leakage direction of the built-in mechanical seal is opposite to the direction of centrifugal force. Therefore, the built-in mechanical seal is generally selected. Only when the medium is extremely corrosive and do not want to consider the use of pressure double mechanical seals, consider choosing external mechanical seals.
Features of built-in mechanical seal:
1. It can be used in environments with higher temperature and pressure.
2. The force is in good condition, and the density is extremely good;
Features of external mechanical seal:
1. Suitable for use in low pressure or negative pressure environment;
2. The moving ring is installed outside the stuffing box, which is convenient for inspection and adjustment;
3. Due to the process, most of the parts are not easily corroded without contact with the medium, and they are easy to install and maintain.