Which part of an air compressor automatically opens when the piston moves down?

The intake valve is the component that automatically opens when the piston moves down. As the piston descends in the cylinder during its intake stroke, it creates a vacuum, causing the pressure inside the cylinder to drop. This drop in pressure allows the intake valve to open, permitting external air to enter the cylinder.

This action is crucial for the proper operation of the air compressor, as it allows the system to draw in air, which will later be compressed as the piston moves back up. The effective functioning of the intake valve is essential for maintaining the cycle of air intake and compression, thus ensuring that the compressor can build pressure and operate efficiently.

Other components, like the discharge valve, serve different functions, such as allowing air to exit the compressor after it has been compressed. The piston itself is the moving part that creates the necessary pressure changes for the intake and does not open; it is simply a mechanism within the system. The air receiver stores compressed air but does not play a role in the function of opening during the piston’s downward movement.