Flow meter and bubble trap for blood being dialysed - has two chambers with second very wide communicating through openings one above and one below blood level

摘要

Two chambers (C, D) communicate by a gap (E) in the dividing partition (s) below fluid level, and by another gap (F) above it, which equalises the air pressure on the two surfaces. Blood entering one chamber (C) passes through the submerged gap (E) and leaves from the other (D). As the gap (E) is narrower than the entry orifice (a) there is a difference in the liquid levels in the two chambers that indicates the flow rate. The outlet chamber is considerably wider, so that its fluid level (V2) changes comparatively little. The flow rate is given by the level (V1) in the inlet chamber. Air bubbles in the blood rise to the surface in the inlet chamber (C) or in the outlet chamber (D) where the liquid flows slowly and quietly.