Check valve

1. A check valve comprising:

a valve seat member provided with a fluid circulation port;

a round plate-shaped valve member provided on a downstream side of the valve seat member and configured to open/close the circulation port;

a spring provided on a downstream side of the valve member and configured to bias the valve member toward the circulation port;

a spring receiving member provided for the spring on a downstream side thereof; and

a plurality of round guide rods

provided at a periphery of the valve member and formed to extend in an upstream-to-downstream flow direction,

each having a downstream end portion attached to the spring receiving member, and

each being in contact with an outer circumferential surface of the valve member to thereby guide the valve member in the upstream-to-downstream flow direction,

wherein an upstream end portion of each guide rod is inserted into a periphery of the circulation port of the valve seat member and attached to a screw hole of an insertion member,

the spring receiving member is fixed with nuts with a lower end portion of each guide rod being inserted into the spring receiving member,

the spring receiving member has a recess which is formed at a center of the spring receiving member and into which a downstream end portion of the spring is inserted,

a bottom wall of the recess is provided with a plurality of openings forming a fluid circulation path,

a threadedly-engagement member is directly threadedly engaged with an outer periphery of a discharge pipe, and

the insertion member is inserted into the discharge pipe and fixed to the threadedly-engagement member with bolts.