Constant flow valve

A constant flow valve comprising a stop-valve-type valve body having inlet and outlet passages which follow a curve of an inside partition wall, and a hollow chamber disposed between the inlet and outlet passages to communicate with the inlet passage, an axis of the hollow chamber being inclined at a certain angle with respect to an axis of the inlet passage;

• and opening arranged inside the valve body to connect the outlet passage with the hollow chamber, having an inner circumferential face tapered inwardly from an upstream side toward a downstream side;
• a lid body fitted to the valve body;
• a spindle supported by the lid body and movable back and forth along an axis thereof which substantially matches the axis of the opening;
• a cylinder integrally arranged at a lower end of the spindle on the upstream side to be movable back and forth inside the hollow chamber, a lower end face of the cylinder being capable of coming into contact with a valve seat portion of the opening;
• a valve shaft freely arranged inside the cylinder substantially on the axis of the opening;
• a valve plug on the upstream side fitted to a front end of the valve shaft to form an orifice between the valve plug and the opening;
• at least one of the valve shaft and the valve plug being formed as a solid article;
• and a plurality of springs having different spring constants and being disposed inside the cylinder to force the valve plug away from the opening in such a manner that the expanding or contracting actions of the springs start at different timings in response to changes in a fluid pressure.