Variable Circulation Rate Sub for Delivering a Predetermined Straight through Flow

A housing is integrated into a tubing string having a straight through passage and a lateral wall exist. Inside the passage is a flow responsive member with an applied preload force. Flow corresponding to a predetermined differential pressure in the housing will not move the valve member so all flow will go straight through in a downhole direction. As flow increases, the preload bias is overcome to align the passage through the housing and openings in the valve member with wall openings. As flow into the housing increases, more lateral wall opening area is aligned with the passage to increase circulation flow while holding through flow downhole constant. Dropping a ball on the valve member blocks through flow and allows opening of total bypass passages. The ball can be removed by blowing it through the seat or otherwise failing or disintegrating it.