The composition and classification of mechanical seals Basic components and functions of mechanical seals

The composition and classification of mechanical seals. The basic components and functions of mechanical seals. The mechanical seal is a device composed of at least a pair of end faces perpendicular to the axis of rotation, under the action of fluid pressure and the elastic (or magnetic force) of the compensation mechanism. It cooperates with the auxiliary seal to keep the seal closed and Relative sliding. Prevent fluid leakage from each other. The composition of the mechanical seal (1) The main components, including the moving ring and the static ring; (2) Auxiliary seals, mainly refers to the sealing ring; (3) Elastic force compensation mechanism, mainly including springs and push rings; (4) Transmission parts, The bullet base and the key or various screws. According to whether the spring element is rotating or static, the mechanical seal can be divided into rotating type and static type; according to the leakage direction of the sealing medium, it can be divided into two types: internal flow type and external flow type; according to the unloading situation caused by the medium on the end surface, It can be divided into two types: balanced and unbalanced; according to the position of the static ring, it can be divided into internal and external; according to the temperature in the sealed cavity, it can be divided into four types: high temperature sealing, medium temperature sealing, normal temperature sealing and low temperature sealing. Type; According to the pressure in the sealed cavity, it can be divided into ultra-high pressure mechanical seal, high pressure mechanical seal, medium pressure mechanical seal and low pressure mechanical seal; according to the number of springs, it can be divided into single spring type and multiple spring type; according to non-contact type Mechanical seal structure can be divided into hydrostatic type, hydrodynamic pressure type and dry gas seal type; according to the elastic element, it can be divided into spring compression type and bellows type. Basic components and functions of mechanical seal (1) The dynamic and static rings are kept in close contact to form a sealing surface to prevent medium leakage. The moving and static rings are required to have good wear resistance. The moving ring can move axially and automatically compensate for the wear of the sealing surface to make it fit well with the static ring. The static ring has a floating property and serves as a buffer. (2) Elastic elements (springs, corrugated plates, serpentine sleeves, etc.) mainly play compensation, pre-tightening and buffering functions, and are also factors that produce a reasonable specific pressure on the seal end surface. It is required to always maintain elasticity to overcome the friction between auxiliary seals and transmission parts , Start ring compensation. The material requires corrosion resistance. (3) Auxiliary seals (O-ring, V-ring, wedge-shaped ring and other special-shaped sealing rings) mainly play the role of sealing the static ring and the moving ring, and also play the role of floating and buffering. The auxiliary sealing element of the static ring is required to ensure the sealing performance between the static ring and the gland, so that the static ring has a certain degree of floating; the auxiliary sealing element of the moving ring ensures the seal between the moving ring and the shaft or sleeve. The material is required to be resistant It is close to the medium in terms of heat and cold resistance. (4) Transmission parts Transmission parts include transmission pins, transmission rings, transmission seats, transmission sleeves, transmission keys, transmission lugs or jaw couplings, and their function is to transmit the torque of the shaft to the moving ring. The material requires corrosion resistance and wear resistance. (5) Fasteners Fasteners include: set screws, spring seats, glands, assembly sleeves, and shaft sleeves. It plays the role of positioning and securing the static and moving rings. It is required to be positioned correctly, to ensure that the sealing surface of the friction pair is in the correct position, and to maintain a well-fitting spring pressure ratio; at the same time, it is required to be easy to disassemble, easy to place, and reusable; pay attention to the installation of the sealing ring in the matching part of the auxiliary seal. Angular and compressive elasticity, pay special attention to the requirements of corrosion resistance and wear resistance at the matching part of the moving ring seal ring and the shaft sleeve, and use hard surface cladding if necessary.