Experimental Study on Active Pneumatic Damping of Pulsatile Flow Delivered From Peristaltic Pump

Hemodynamic flow loops are widely used for research on causes and cures of cardiovascular diseases. They replicate physiological blood flow pulsatility in vitro. Many different pump types exist for such flow loops. The variety of the flow loop types shows the lack of one concept that satisfies all requirements, which are ease of handling and sterilization, flexible and accurate realization of various profiles, low shear rate exerted on fluid, low amount of circulating fluid. This paper experimentally proves the concept of a new type of pulse damping/pulse generating device that can be used for flow loops that are operated with a peristaltic pump. The pulse generating device fulfills the double function of damping the undesired pulsatility of the peristaltic pump and injecting a desired pulsatility that replicates the flow profile delivered by the heart. The injection of the desired pulsatility is achieved by modulation of air pressure in a damping device. The experimental results show that it is possible to achieve the dual function in one device. An electromagnetic flow sensor provides the feedback for the air pressure control and a high-response flow control valve controls the pressure in the pulse damper/generator. The response time and accuracy of the sensor proved to be critical for achieving the objective. With the limitations of the relatively cheap components used for this functional prototype, the mean error in the flow rate signal could be kept below 10% for a simulated adult pulse rate of 60bpm.