Check valve and scroll compressor

A check valve, comprising a valve plate, a washer, a valve stem, and a valve stopper, wherein

• the valve stem is fixedly arranged between the valve plate and the valve stopper,
• the valve plate is provided with a valve hole for fluid to flow through,
• an outer stopper edge, a middle stopper edge, and an inner stopper edge each having an annular shape are provided on a bottom surface of the valve stopper from an edge to a center,
• a reverse flow hole is provided between the outer stopper edge and the middle stopper edge, and a ventilation port is provided on the middle stopper edge, and the ventilation port is configured to connect a gap between the outer stopper edge and the middle stopper edge with a gap between the middle stopper edge and the inner stopper edge in a case that the washer is in contact with the outer stopper edge, the middle stopper edge, and the inner stopper edge;
• and
• the washer is configured such that:
• in a case that there is fluid flowing out of the valve hole, the washer moves to a top dead center along the valve stem and is in contact with the outer stopper edge, the middle stopper edge, and inner stopper edge of the valve stopper;
• and
• in a case that there is no more fluid flowing out of the valve hole, the fluid flows into the gap between the outer stopper edge and the middle stopper edge through the reverse flow hole, then flows into the gap between the middle stopper edge and the inner stopper edge through the ventilation port, the washer moves to a bottom dead center along the valve stem under a pressure of the fluid in the gap between the outer stopper edge and the middle stopper edge and the gap between the middle stopper edge and the inner stopper edge, to close the valve hole.