Pneumatic quick couplings can be classified according to their structures.

Two-way Shut-off Type

· When not connected: When the collar of the female part moves to the other end, the stainless steel balls of the hydraulic joint automatically roll outwards. Under the action of the combined force of the valve springs of the female and male parts, the male part disconnects, and the valves of the male and female parts close respectively, instantaneously blocking the fluid flow.
· When connected: When the male part is inserted into the female part, the collar returns to its original position under the action of the spring, and the balls roll and clamp the male part for sealing connection. At the same time, the valves of the female and male parts push each other and open, allowing the fluid to flow. The O-ring can completely prevent fluid leakage.

Two-way Open Type

· When not connected: When the collar of the female part is pushed to the other end, the balls automatically roll outwards, so the male part of the air pipe joint is removed. Since neither the male nor the female part has a valve, the fluid flows outwards.
· When connected: When the male part is inserted into the female part, the collar is pushed back to its previous position by the action of its spring, causing the balls to clamp and the fluid to flow. The O-ring among them prevents liquid leakage.
One-way Shut-off Type
· When not connected: When the collar of the female part moves to the other end, the stainless steel balls automatically roll outwards, and the male part is bounced back by the reaction force of the valve spring, and the valve can automatically close to block the fluid flow.
· When connected: When the male part is inserted into the side of the female part with the collar, the valve is opened to cause the fluid to flow. The sealing ring is pushed back to its original position by the force of the spring, and the stainless steel balls are locked to ensure the connection between the male and female parts. The sealing ring inside can completely prevent fluid leakage.