Linkage-type constant-pressure valve

A linkage-type constant-pressure valve comprising:

• a valve body formed with a first valve chamber being in communication with an inlet flow passage, a second valve chamber being in communication with an outlet flow passage, and a communication passage communicating the first valve chamber and the second valve chamber with each other;
• a valve seat formed in the communication passage;
• a valve mechanism including a first diaphragm attached to the valve body so as to face the first valve chamber and supporting a valve element portion movable in a direction of a movement axis relative to the valve seat, and a second diaphragm attached to the valve body so as to face the second valve chamber;
• a first force-applying mechanism attached to the valve body and applying a force to the first diaphragm in a direction to bring the valve element portion closer to the valve seat;
• and a second force-applying mechanism attached to the valve body and applying a predetermined force in a direction to bring the second diaphragm closer to the communication passage, said valve element portion moved relative to the valve seat in accordance with the pressure of a fluid in the second valve chamber,
• wherein the first force-applying mechanism comprises a first mechanism housing having a first mechanism accommodating chamber formed therein, a first movable body accommodated in the first mechanism accommodating chamber and movable in the direction of the movement axis, a biasing member provided in the first mechanism accommodating chamber and biasing the first movable body in a direction to approach the communication passage, and a stem extending from the first movable body through the first mechanism housing and connected to the valve element portion of the first diaphragm,
• wherein the second force-applying mechanism comprises a second mechanism housing having a second mechanism accommodating chamber formed therein, a second movable body accommodated in the second mechanism accommodating chamber and movable in the direction of the movement axis, an applied force adjustment mechanism applying an adjustable predetermined force to the second movable body in a direction to approach the communication passage, and a force transmission portion extending from the second movable body through the second mechanism housing and transmitting a force between the second movable body and the second diaphragm, and
• wherein a rod-shaped link member is provided so as to be arranged between the first movable body and the second movable body and extend through the valve body outside the first valve chamber and the second valve chamber in the direction of the movement axis, so that the first movable body and the second movable body are moved in conjunction with each other via the link member.