Fluid controller with diaphragm

A fluid controller comprising:

• a body provided with a fluid passage;
• a casing mounted above the body via a bonnet;
• a diaphragm configured to open and close the fluid passage;
• a stem configured to move the diaphragm to an open or close direction by moving upward or downward, the stem having a flange portion at a lower end portion of the stem which extends radially from an upper surface of a diaphragm holder to the bonnet;
• the diaphragm holder fixed to the lower end portion of the stem;
• a holder adapter disposed radially outside the diaphragm holder and fixed to the body, and configured to hold an outer peripheral edge portion of the diaphragm;
• a piston configured to move upward and downward integrally with the stem;
• and
• drive means configured to move the piston upward and downward,
• wherein a gap between an upper surface of an outer peripheral edge portion of the diaphragm holder and a lower surface of an inner peripheral edge portion of the holder adapter is set as a first gap, and an upward movable amount of the diaphragm holder is set by the first gap, and
• wherein a second gap for setting a downward movable amount of the stem is a space bound by a lower surface of the flange portion provided at the lower end portion of the stem and an upper surface of the holder adapter and the second gap is set to a predetermined value for fluid controller operation.