Because the movement of butterfly valve plate is wiping, most butterfly valves can be used for media with suspended solid particles, and can also be used for powdery and granular media according to the strength of seals.

Detailed explanation of electrolytic polishing technology for inner surface of corrugated pneumatic butterfly valve pipe
Electrolytic polishing solution is phosphoric acid, sulfuric acid, chromic anhydride, gelatin, potassium dichromate, etc. The inner and outer surfaces of the pneumatic butterfly valve are on the anode, and the polishing liquid moves in the anode and connects with low voltage and high current to stop electrolytic polishing. At this time, two contradictory processes, namely, the formation and dissolution of the passivation layer (containing thick mucous membrane) on the metal surface, are stopped on the inner and outer surfaces of the tube at the same time. Because the conditions for film formation and passivation in the convex and concave parts of the microscopic appearance are different, and because of anodic dissolution.
Due to the different conditions for film formation and passivation at the micro convex and concave parts of the surface, and due to anodic dissolution, the concentration of metal salts in the anode area increases from time to time, forming a thick membrane with high resistance on the surface. The thickness of the film at the concave and convex points leads to large current density on the anode surface and fast discharge dissolution, which can achieve the goal of flattening the protruding microscopic parts in a short time, and can achieve high brightness Ra ≤ 0.2-0.4 μ m。 Under this effect, the chromium content on the inner surface of the tube increases, and the corrosion resistance of the passivation layer on the outer surface of the metal increases.
How to control the quality of polishing is related to the electrolyte formula, concentration, temperature, power on time, current density, electrode condition, tube surface treatment level, etc. If the technology is not well controlled, the brightness of the tube surface will be damaged. If the electrolysis level is too high, more and larger concave and convex surfaces will appear, so that the tubes will be scrapped. If the quality is really good, it needs certain technology, and the cost is high.