Diaphragm valve and monitoring method thereof with improved leak detection

A monitoring method of a diaphragm valve, the diaphragm valve comprising:

• a valve body defining a flow path through which a fluid flows, and an opening which opens to the outside in a middle of the flow path;
• a flexible partition member covering the opening, separating the flow path from the outside, and changing a cross-sectional area of the flow path;
• a flexible support member disposed on a rear surface side opposite to a flow path side of the flexible partition member;
• and a housing fixed to the valve body via peripheral portions of the flexible partition member and the flexible support member, the monitoring method comprising:
• detecting a humidity or change thereof of an atmosphere in a space defined by an inner surface of the flexible support member and the housing by a humidity sensor that has a flat plate shape having a hole in a center and is disposed on a ceiling of said space, or by a humidity sensor that is disposed on a surface of a compressor between the flexible support member and the compressor;
• and
• determining abnormality based on the detection result.