Introduction to the four characteristics of GSJ

During many years of production and experiments, we discovered and preliminarily mastered the sealing characteristics of GSJ. According to the changing characteristics of the sealing curve of GSJ - the curve of leakage Q changing with oil pressure P (as shown in Figure 3), we can temporarily divide it into four areas: sub-sealing area, sealing unstable area, sealing area and sealing failure area.

1. Sub-sealing area - When the pressure is in the range of 0-0.6MPa, GSJ will be in a sub-sealing state. At this time, the leakage of hydraulic oil through the gap Q is also very small, almost 0, and it can be considered to be in a sub-dynamic equilibrium period.

2. Sealing unstable area - As the oil pressure P gradually increases, when the pressure is in the range of 0.6-1.5MPa, the sub-dynamic balance in the sub-sealing state will gradually be destroyed, the internal leakage of the hydraulic cylinder Q will increase, and the sealing performance of GSJ is in a sealing unstable area.

3. Sealing area - The pressure P of GSJ in the sealing area is approximately between 3MPa-32MPa, which can generally meet the sealing requirements of the hydraulic cylinder under working night and pressure resistance conditions, and belongs to the normal working pressure area. At this time, under the combined effect of oil pressure, extrusion pressure of the O-ring and other comprehensive factors, the sliding ring and the surface of the metal part are tightly fitted together, and only a thin layer of oil film is formed between the sliding pairs.

4. Seal failure zone - If the oil pressure P of the hydraulic system is greater than the withstand pressure of the step seal and continues to rise, the sealing of the GSJ will be destroyed and the internal leakage Q will increase. In addition, if used improperly, the sliding ring may burst and the seal may fail. The oil pressure in the seal failure zone will have a destructive effect on the hydraulic cylinder and the seal ring. Therefore, overflow valves, pressure reducing valves or pressure limiting valves are often installed in the pipelines of the hydraulic system to protect the hydraulic system.