Patent ID: 7175157

Claim:
A fluid controller comprising: a block-like main body having a fluid inflow passage, a fluid outflow passage and a concave portion open upward; and a diaphragm pressed against or moved apart from an annular valve seat arranged within the concave portion of the main body so as to open and close the fluid passages, wherein the concave portion is formed into a shape including a large-diameter portion close to the opening and a small-diameter portion connected to a lower side of the large-diameter portion via a step portion, and the fluid controller is further provided with a flow path forming disk fitted to the concave portion, the flow path forming disk includes a large-diameter cylinder portion fitted to the large-diameter portion of the concave portion in a fluid tight manner, a small-diameter cylinder portion having an outer diameter smaller than an inner diameter of the small-diameter portion of the concave portion and having a lower end received by a bottom surface of the concave portion, and a coupling portion coupling a lower end portion of the large-diameter cylinder portion and an upper end portion of the small-diameter cylinder portion and received by the step portion of the concave portion, and a peripheral edge portion of the diaphragm is fixed to an upper end portion of the large-diameter cylinder portion of the flow path forming disk, a valve seat is provided in the upper end portion of the small-diameter cylinder portion of the flow path forming disk, an inner annular space of the large-diameter cylinder portion is formed by an inner periphery of the large-diameter cylinder portion of the flow path forming disk, the diaphragm, the valve seat and a top surface of the coupling portion of the flow path forming disk, a plurality of through holes communicating an outer annular space of the small-diameter cylinder portion formed between the small-diameter cylinder portion of the flow path forming disk and a peripheral surface of the small-diameter portion of the concave portion with an inner annular space of the large-diameter cylinder portion are formed in a coupling portion of the flow path forming disk, any one of the fluid inflow passage and the fluid outflow passage is communicated with a lower end of the small-diameter cylinder portion of the flow path forming disk, and the other is formed so as to be communicated with the outer annular space of the small-diameter cylinder portion.