Pump Design for a Portable Renal Replacement System

Abstract

This work proposes a small, light, valve-less pump design for a portable renal replacement system. By analyzing the working principle of the pump and exploring the design space using an analytical pump model, we developed a novel design for a cam-driven finger pump. Several cams sequentially compress fingers, which compress flexible tubes, thus eliminating valves. Either changing the speed of the motor or size of the tube can control the flow rate. In vitro experiments conducted with whole blood using the pump measured Creatinine levels over time, and the results verify the design for the portable renal replacement system. The proposed pump design is smaller than 153 cm3 and consumes less than 1W while providing a flow rate of more than 100ml/min for both blood and dialysate flows. The smallest pump of a portable renal replacement system in the literature uses check valves, which considerably increase the overall manufacturing cost and possibility of blood clotting. Compared to that pump, the proposed pump design achieved reduction in size by 52% and savings in energy consumption by 89% with the removal of valves. This simple and reliable design substantially reduces the size requirements of a portable renal replacement system.

New Dialysis Technology and Biocompatible Materials

“…The advantage of this design is that alternating pressure waves across the capillary dialyzer reduces protein deposition on the membrane surface, so improving transfer of larger solutes and middle molecules [7]. Alternative designs to develop smaller more ergonomically efficient blood pumps for dialysis include ripple pump technology, in which a series of fingers are aligned on both sides of the blood tubing, and controlled by a cam mounted on a shaft and oriented at different angles so that they sequentially activate the fingers to propel blood forward [8].…”

Data-driven product family design for additive manufacturing

“…To address the demand for portable home haemodialysis devices, initial investigations demonstrated that substantial improvements in pump size and eciency were possible [191,192]. An alternative to the roller pump, called a nger pump, has been developed by…”

“…Kang [192]. The nger pump maintains the benets of traditional positive displacement roller pumps (i.e., no uid contamination) with the added benets of higher eciency and smaller size compared to pumps with a similar ow rate, as well as a reduction in clotting when pumping biological uids.…”

“…The product family is motivated specically by the need for new haemodialysis systems, but it has a broader market base when more application domains are considered. [192]).…”

“…The achieved pump ow rate, eciency are represented by f r and η respectively. The mathematical model of the nger pumper in this work is developed according to Kang et al [192]. The following equations describe the relationship between the variables.…”