The difference between internal and external mechanical seals

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 parts equivalent to the sealing gland) (that is, the side facing the working chamber of the main engine) is called a 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 sealing chamber;

External mechanical seal: refers to the mechanical seal installed outside the sealing chamber;

Since the built-in mechanical seal has a good stress condition, the specific pressure increases with the increase of the medium pressure, and the leakage direction of the built-in mechanical seal is opposite to the direction of the centrifugal force, so the built-in mechanical seal is generally used. Only when the medium is extremely corrosive and you don’t want to consider using a pressurized double mechanical seal, you should consider choosing an externally mounted mechanical seal.

Built-in mechanical seal features:

1. It can be used in environments with high temperature and pressure;

2. Good stress condition and excellent sealing performance;

External mechanical seal features:

1. Suitable for 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 technical relationship, most parts are not easy to be corroded without contact with the medium, and are easy to install and maintain;