Believe Rotary Shaft Seal Sealing Principle

Mechanical seals rely on the tight contact between the end faces of the rotating and stationary rings under fluid pressure and the action of elastic elements (such as springs), forming a small contact pressure to prevent fluid leakage. The rotating ring rotates with the shaft, while the stationary ring is fixed to the pump casing or equipment end cover. Sealing is achieved through relative sliding between the end faces.

Packaging seals use elastic packing (such as packing, asbestos rope, carbon fiber braided packing, etc.) to fill the stuffing box. Axial pressure is applied through the gland, causing radial deformation of the packing, which then grips the shaft or bushing, blocking fluid leakage channels. Sealing is achieved through friction between the packing and the shaft (or bushing).

Believe rotary shaft seals have three seals. The first is a radial seal, where silicone grips the shaft end to prevent material leakage (both end faces have radial seals). The second is an air seal, where the pressure in the sealing cavity is greater than the pressure in the hopper, preventing material from entering the sealing cavity. The third seal is a double-end-face seal, where compressed air and springs push outwards to form an end-face seal with the housing surface.