Check valve

The utility model relates to a check valve, include by the last installation department that down sets gradually, forced section and switch portion, the forced section includes rake and section of thick bamboo portion, the rake is including set up the two first inclined planes that just slope set up in opposite directions, and the interval between the two first inclined planes is along being reduced by last direction down, section of thick bamboo portion includes two sides that set up in opposite directions, and two sides are followed the circumferencial direction by the relative both sides side on one of them first inclined plane and are extended and connection formation toward the relative both sides side on another first inclined plane respectively, switch portion is including the two switch pieces that set up in opposite directions, two switch pieces respectively by the bottom tip on two first inclined planes down extends formation along the check valve axial, the butt joint of laminating each other of tw