Structural features and types of mechanical seals

Structural features and types of mechanical seals In order to get used to the needs of different operating conditions, mechanical seals have a variety of different types: 1. According to the logarithm of the seal end face, it is divided into single end face, double end face and other mechanical seals. Single end face-only a pair of sealing end faces in the sealing equipment. It has a simple structure and is a commonly used type of mechanical seal. Double end faces-There are two pairs of sealing end faces in the sealing device. It has a complex structure and is suitable for strong corrosion, flammable cartridge mechanical seals, explosives, toxic and harmful media, and vacuum occasions. 2. According to the pressure of the sealing fluid acting on the end face of the seal, Grundfos mechanical seals are unloaded or not unloaded, and can be divided into balanced and unbalanced mechanical seals. Balanced type-the sealing fluid acts on the sealing end face to press the inlet mechanical sealing force to partially unload or fully unload. Unbalanced type-the pressure of the sealing fluid acting on the sealing end face is not unloaded. The balanced type is suitable for mechanical seals under medium and high pressure conditions; the unbalanced type is suitable for mechanical seals under low pressure conditions. 3. According to whether the tension spring is placed in the sealing fluid, it is divided into the internal tension spring and the external tension spring mechanical seal. Built-in tension spring-the tension spring is placed in the sealing fluid. External tension spring-the tension spring is placed outside of the sealing fluid. The internal sealing end face of the tension spring has a good stress state, small leakage, and good cooling and lubrication. Therefore, in addition to corrosive media, the built-in structure should be used as much as possible. 4. According to the number of springs in the compensation structure, it is divided into single spring type and multiple spring type mechanical seals. Single spring type-only one spring in the compensation organization. It is used where the load is lighter and the shaft diameter is small. Multiple springs-there are multiple springs in the compensation organization. Used for larger shaft diameters. The tension spring force is distributed more evenly on the sealing end surface, but the diameter of the tension spring wire is small, and corrosion has a greater impact on the tension spring. 5. According to whether the compensation organization rotates with the shaft, it is divided into rotary and stop mechanical seals. Rotary type-the compensation ring rotates with the shaft. Stopped type-the compensation ring does not rotate with the shaft. Normal mechanical seals often use the rotary type, due to the simple structure of the compensation organization and shaft, the radial dimension is small. However, under high-speed conditions, the centrifugal force generated by the compensation ring and other rolling parts has a greater impact, and the dynamic balance request is high, so the stop type is more appropriate. From the perspective of structural features, there are many types of mechanical seals, but in terms of composition, it mainly has the following four basic unit components: 1. The buffer compensation unit is composed of a tension spring as the primary component. It is a buffer compensation organization that maintains the mechanical seal. Important conditions for normal operations. 2. The sealing unit is the sealing end surface composed of the moving ring and the static ring, which is the core of the mechanical seal. 3. The auxiliary sealing unit is composed of moving ring sealing ring and static ring sealing ring. It is an auxiliary sealing organization that solves the parts that may leak outside the sealing end face, and is an indispensable component of mechanical seals. Mechanical seal is a very promising form of sealing in fluid sealing technology. It has now reached the level of operating pressure of 40MPa, uniform sliding speed of the end face of 150m/s, and pv value of 200MPa•m/s. It can meet the requirements of most production process conditions. 4. The transmission unit consists of a shaft sleeve, a key or a fixed pin. It is a reliable guarantee to complete the rotation of the moving ring with the shaft, and it is also a prerequisite for the completion of the dynamic seal. Keywords: Grundfos mechanical seal, imported mechanical seal, cartridge mechanical seal