Device for the acoustic detection of gas bubbles in liquids such as blood or infusion solutions

摘要

For monitoring of liquids in the medical field, e.g. blood, for freedom from gas bubbles the invention proposes an ultrasonic pulse echo method in which an ultrasonic emitter (2) which emits short ultrasound pulses rests against the wall of a cylindrical measuring chamber. If a gas bubble is present inside the measuring chamber in the liquid the ultrasound pulse is scattered thereon and received by an ultrasonic receiver (3). The ultrasonic emitter (2) and the ultrasonic receiver (3) are arranged at an angle of 60...80 DEG relative to one another. The ultrasonic wave reflected at the rear wall of the measuring chamber (1) in region (7) and received by the ultrasonic receiver (3) is used as a reference signal and permits elimination of fluctuations in the coupling between ultrasonic emitter (2) or ultrasonic receiver (3) and measuring chamber (1) and detection of a completely empty or missing measuring chamber (1) and of defective electronic components. <IMAGE>