Development of the crank-motor vibrating flow pump for the left ventricular assist system

A new type of crank-motor actuator was used to improve the vibrating flow pump (VFP). The linear-motor actuator has the advantage of a flexible driving frequency and driving stroke, but it makes the total system heavy due to its low driving force within the target frequency (∼10-40 Hz). The crank-motor structure has an advantage in that it enables an effective driving force within the target frequency, but it has a linear relationship between driving frequency and pumping output because of the fixed stroke of the crank. This linear relationship restricts the driving conditions. The newly designed crank-motor VFP is developed as a left ventricular assist system. It's driving condition was scheduled as 100 mm Hg/5 L min^-1/∼20-25 Hz. A study determined that a driving stroke of 5 mm and a diameter of 10 mm were needed to drive the vibrating central tube. The trial crank-motor VFP was made to these specifications. The new VFP is 100 × 50 × 72 mm (L × W × H) and weighs 320 g. This pump almost satisfied the required pumping performance for left ventricular assistance. The new type crank-motor VFP may become a good pump with careful revision of its design and may be used in experiments for the studies of oscillated blood flow and impedance of the circulatory system.