Mass flow controller

A mass flow controller comprising:

• a flow meter;
• a mechanical pressure-regulating valve disposed adjacent to and on an upstream side of said flow meter;
• and
• a flow control valve disposed on a downstream side of said flow meter, wherein:
• said mechanical pressure-regulating valve is embedded in a base of said mass flow controller.

A mass flow controller comprising:

• a flow meter;
• a flow control valve disposed on a downstream side of said flow meter;
• a mechanical pressure-regulating valve disposed adjacent to and on an upstream side of said flow meter, said mechanical pressure-regulating valve is embedded in a base of said mass flow controller, said mechanical pressure-regulating valve comprises:
• a pressure-regulating chamber which constitutes a part of a channel of a fluid in said mass flow controller;
• and
• a diaphragm which separates an internal region of said pressure-regulating chamber from an external region of said channel;
• said mechanical pressure-regulating valve is configured to be opened by at least one part of said diaphragm being displaced to a side of said pressure-regulating chamber when pressure of said fluid in said pressure-regulating chamber is lower than a predetermined set pressure;
• and
• a compulsive valve-opening mechanism configured to compulsorily open said mechanical pressure-regulating valve, said compulsive valve-opening mechanism comprises a member configured to displace at least said one part of said diaphragm to said side of said pressure-regulating chamber by an external operation.