Flow control valve

A flow control valve comprising:

• a housing defining a fluid passage,
• a valve seat having a ring shape and being disposed in the housing,
• a valve plug movable relatively to the valve seat between a valve open position and a valve closed position in an axial direction of the valve seat, and
• a seal member interposed between the valve seat and the valve plug,
• wherein the seal member has a ring shape and is configured to seal between the valve seat and the valve plug when the valve plug is in the valve closed position,
• wherein the seal member further comprises
• an annular base portion attached to one of the valve seat and the valve plug, and
• a seal lip having a circular truncated cone shape and protruding obliquely inward in the axial direction from a surface of the base portion,
• wherein the seal lip is configured to be separated from the other of the valve seat and the valve plug when the valve plug is in the valve open position,
• wherein the seal lip is configured to elastically contact the other of the valve seat and the valve plug when the valve plug is in the valve closed position,
• wherein the surface of the base portion has a circular recess extending continuously in a circumferential direction and having an inner surface continuous with an inner circumferential surface of the seal lip,
• wherein the inner surface of the recess comprises a concave curved surface having an arcuate cross section,
• wherein the concave curved surface is smoothly continuous with the inner circumferential surface of the seal lip,
• wherein the seal member comprises a convex curved surface having an arcuate cross-section, and
• wherein the convex curved surface smoothly connects the concave curved surface to the surface of the base portion.