Fluid supply device

A valve for use in a fluid supply device including a fluid supply source, a differential-pressure generator, and a pressurizing device, the valve comprising:

• a valve casing;
• a displacement member that divides the valve casing into a first valve chamber and a second valve chamber, the displacement member being displaced by a pressure of a fluid being exerted on a front main surface and a back main surface of the displacement member;
• a first opening provided on a side of the valve casing on which the first valve chamber is provided, the first opening being connected to a fluid inflow side, and the first opening being arranged to be connected to an ejection side of the differential-pressure generator that generates a pressure difference between the first valve chamber and the second valve chamber;
• a second opening provided on the side of the valve casing on which the first valve chamber is provided, the second opening being connected to a fluid outflow side;
• and
• a third opening provided on a side of the valve casing on which the second valve chamber is provided, the third opening being an opening through which a fluid flows inward, the fluid being separated from the fluid flowing inward through the first opening and supplied from the fluid supply source that also supplies the fluid flowing inward through the first opening;
• the displacement member is arranged to be urged by the pressurizing device toward the first valve chamber and prevents the first opening and the second opening from being connected to each other;
• and
• the displacement member is arranged to be displaced so as to connect the first opening and the second opening to each other when a force of the fluid flowing through the first opening exerted on the main surface of the displacement member facing the first valve chamber is greater than a force of the fluid flowing through the third opening exerted on the main surface of the displacement member facing the second valve chamber.