2026-06-06

What is the working principle of the sealing element?

This is the most ingenious part of many seals - the higher the medium pressure, the tighter the seal becomes. It doesn't rely on elastic deformation; instead, it uses "curved channels" to dissipate the pressure. By making several grooves on the shaft and adding several raised platforms on the cover, for gases or liquids to leak out, they must follow an S-shaped path. With each turn of the shaft, a portion of the pressure is lost. By the time it reaches the outlet, the pressure is already close to zero. Steam turbines and compressors often use this type. The advantage is that there is no friction, no wear, and an extremely long service life.

2026-06-06

How to Select Ball Valves and Globe Valves According to Actual Requirements

When the pipe diameter is large and the main function is to enhance the conveying efficiency, a ball valve should be chosen; when the pipe diameter is small and the focus is on process adjustment, a stop valve should be selected. Corrosive medium: It is recommended to pair with ball valves of the corresponding material. The flow path has no dead corners and is not prone to accumulation of dirt or corrosion. Budget considerations: For the same specifications, the price of conventional ball valves is lower. For large-scale civilian pipeline applications, priority should be given to them. For industrial high-temperature and high-pressure process pipelines, stop valves should be chosen as the priority; there is no need to worry about the price difference.

2026-06-06

What are the non-destructive testing methods for forgings?

Principle: The forging is magnetized. Surface defects will cause magnetic leakage. After spraying magnetic powder, the magnetic powder gathers to reveal the defect patterns. Applicable to: Forgings of ferromagnetic materials such as carbon steel and chromium-molybdenum steel, only inspect surface and shallow micro-cracks, folds, streaks, and grinding cracks. Valve scene: Surface screening of high-temperature and high-pressure carbon steel, chromium-molybdenum steel valve bodies, and flange forgings. Limitations: Austenitic stainless steel (304/316) is non-magnetic and cannot be tested using MT; it can only be used for shallow layer testing, and deep layer defects are not applicable. 3. Penetrant Testing (PT) (Surface Opening Defects on Stainless Steel / Non-magnetic Components) Principle: After cleaning the workpiece, apply the penetrant liquid. The liquid penetrates the surface opening defects. Then, wash away the excess penetrant liquid. The developer absorbs the colored traces to reveal the cracks. Applicable to: Non-magnetic forged parts made of stainless steel, copper alloy, aluminum alloy, etc. Detect all surface defects: surface cracks, folds, pinholes, sand holes. For the stainless steel valve body forgings of ball valves, the surface flaw detection method is the preferred choice. Limitations: It can only detect defects from the opening to the surface, while internal and buried defects cannot be detected; the surface roughness of the workpiece requires high standards.