Two methods of silicon carbide ring sintering, namely pressureless sintering and reaction sintering, were adopted. Silicon carbide products with different sintering methods have different physical and chemical properties, and the comprehensive performance of pressureless sintered silicon carbide is better than that of reaction sintered silicon carbide.

According to different manufacturing methods, there are several types: atmospheric pressure sintered silicon carbide, reaction sintered silicon carbide, hot pressed sintered silicon carbide, chemical vapor reaction silicon carbide, and chemical vapor deposition silicon carbide. As mechanical sealing materials, the first three are the most commonly used.

Mechanical seal (end face seal) is a device used to solve the sealing between the rotating shaft and the body. It is a device that prevents fluid leakage by maintaining contact and sliding relative to each other under the action of at least one pair of fluid pressure and compensation mechanism elastic force (or magnetic force) perpendicular to the axis of rotation, and the cooperation of auxiliary sealing. It is commonly used in rotary fluid machinery such as pumps, compressors, reaction stirrers, and also used for sealing gearboxes, ship stern shafts, etc. Therefore, mechanical seals are a universal shaft sealing device.

There are various types of mechanical seal structures, and the most commonly used mechanical seal structure is the end face seal. The static ring and dynamic ring of the end face seal form a pair of friction pairs, and the function of the friction pair is to prevent medium leakage. It requires both static and dynamic rings to have good wear resistance. The dynamic ring can move flexibly in the axial direction and automatically compensate for the wear of the sealing surface, ensuring a good fit with the static ring; The static ring has floatability and serves as a buffer. Therefore, the sealing surface requires good processing quality to ensure that the sealing pair has good adhesion performance. The basic components that make up mechanical seals include static rings, dynamic rings, pressure covers, push rings, springs, positioning rings, shaft sleeves, dynamic ring seals, static ring seals, shaft sleeve seals, etc.

Elastic components (springs, bellows) mainly serve the functions of pre tightening, compensation, and buffering. It is required to maintain sufficient elasticity at all times to overcome the friction of auxiliary seals and transmission components, as well as the inertia of the dynamic ring, to ensure good fit of the end face sealing pair and the tracking performance of the dynamic ring. The material should be corrosion-resistant and fatigue resistant.

Auxiliary seals (O-rings, V-rings, U-rings, wedge rings, and irregular rings, etc.) mainly serve as seals for static and dynamic rings, as well as for floating and buffering purposes. The sealing element of the static ring is required to ensure the sealing between the static ring and the cover, with a certain degree of floating of the static ring. The sealing element of the dynamic ring should ensure the sealing between the dynamic ring and the shaft or sleeve, as well as the floating of the dynamic ring. The material requires heat resistance, etc.

1. Basic structure

1) End face sealing friction pair

2) Buffer reward and compression mechanism

3) Auxiliary sealing (secondary sealing flexible element)

4) Transmission mechanism

2. Basic sealing point

1) Main sealing point on the end face

2) Static ring and end cap auxiliary sealing point

3) Auxiliary sealing point between dynamic ring and shaft (shaft sleeve)

4) End cap and pump body connection sealing point