A small gap is formed between the sealing end faces of the dynamic and static rings. Due to the pressure of the medium and the force of the spring, there is a certain compression force on the sealing end face, and a layer of liquid film gap is maintained between them. When the medium passes through, the resistance is high, thus preventing its leakage. The presence of liquid film can lubricate the friction surface, thereby reducing friction loss and ensuring sealing effect. Its structure is as follows: (1) Main sealing components (friction pairs): dynamic ring (rotating ring) and static ring (fixed ring, fixed on the gland, prevented from rotating with anti rotation pins). (2) Auxiliary sealing components: sealing rings (O-ring, V-shaped), etc. (3) Compression parts: springs, push rings, etc. (4) Transmission components: transmission seat and keys or fixing screws, etc.
Mechanical seals can be divided into balanced and unbalanced types based on their structure and characteristics, internal and external types, single and multiple springs, single and double end faces, etc.
Briefly describe the functions and methods of the cooling system? In order to improve the operating conditions of pump bearings, seals, and base, a cooling system is generally used. For cold oil pumps, it is usually necessary to provide cooling for bearing housings and sealing glands. For hot oil pumps, the sealing chamber, sealing gland, and pump seat of the bearing box pump are generally cooled. The shaft seal device can be divided into two types: packing seal cooling and mechanical seal cooling. The cooling method of packing seal is to set a cooling water jacket around the packing box, and introduce cooling water to take away the heat generated by the friction between the packing and the shaft (shaft sleeve) to prevent the packing from overheating and burning. The cooling of mechanical seals, in addition to setting a cooling water jacket outside the sealing chamber, usually uses flushing cooling to ensure the normal operation of the seal. The specific method is: the medium is introduced from the pump outlet or other high-pressure system and cooled by flushing on the sealing gland, so that the medium in the sealing chamber is constantly updated, to transmit the frictional heat of the sealing pair and prevent impurities from entering the sealing end faces, The inlet pressure of the flushing fluid must be greater than the sealing chamber pressure by 0.05-0.15Mpa, and it cannot be interrupted during the pump operation. The flushing fluid used for mechanical seals is also the sealing oil of this sealing form. Therefore, the flushing fluid should choose the pump delivery medium or other pollution-free medium. The cooling water pressure of the pump is generally 0.15~0.3Mpa. When connected in series, the cooling capacity of each pump is 0.3-0.7m/h, and when connected in parallel, the cooling water for each bearing, sealing chamber, pump seat, and sealing gland is also estimated at 0.3-0.7m/h.
