A low-cost push-pull syringe pump for continuous flow applications

Abstract

Syringe pumps are very useful tools to ensure a constant and pulsation-free flow rate, however usability is limited to batch processes. This article shows an open-source method for manufacturing a push pull syringe pump, valid for continuous processes, easy to build, low-cost and programmable. The push-pull syringe pump (PPSP) is driven by an Arduino nano ATmega328P which controls a NEMA 17 in microstepping via the A4988 stepper driver. The Push-Pull Syringe Pump setup is configurable by means of a digital encoder and an oled screen programmed using C ++. A PCB was designed and built to facilitate the assembly of the device. The continuous flow is guaranteed by four non-return valves and a dampener, which has been sized and optimized for use on this device. Finally, tests were carried out to evaluate the flow rates and the linearity of the flow. The device is achievable with a cost of less than 100 €.

Keywords: 3D-printing; Continuous flow; Dual syringe pump; Push–pull.

Graphical abstract

Fig. 1

3D printed part of PPSP A) Plunger Mover; B) Screen Holder, C) Motor Holder and Electrical Cabinet; D) Syringe Support; E) Lateral Syringe Holder; F.1) Plunger Holder Front; F.2) Plunger Holder Back; G) Top Syringe Holder.

Fig. 2

PCB specify. TS) Top Silk; TC) Top Copper; TD) Drill position from Top; BS) Bottom Silk; BC) Bottom Copper; BD) Drill position from Bottom.

Fig. 3

PCB assembly.

Fig. 4

Motor Holder & Electrical cabinet and Screen Holder Assembly.

Fig. 5

Syringe Support assembly.

Fig. 6

Plunger mover assembly.

Fig. 7

Mechanical assembly.

Fig. 8

Support assembly.

Fig. 9

a. Schematization of the piping; b. top view of the pump with the tubing; c. focus on the connection of the dampener (in-line mounting, inlet from below) and of the 2 one-way valves.

Fig. 10

Main menu screen representation.

Fig. 11

Calibration line: a. relationship between volumetric flowrate [mL/min] and delay between two consecutive steps in microseconds (for high flow-rate); b. relationship between volumetric flowrate [mL/min] and delay between two consecutive steps in milliseconds (for low flow-rate).

Fig. 12

Operating dampener example.

Fig. 13

Experimental data fitting to correlate $\mathrm{\delta }{\mathrm{V}}_{\mathrm{l}\mathrm{i}\mathrm{q}}$ to the flowrate.

Fig. 14

Demonstration of the dampener effect on a flowrate of 300 mL/min tested in 4 different configurations: without dampener-black line, Small Dampener (V_s = 2.35 cm³)-blue dashed line, Normal Dampener (V_n = 4.7 cm³)-red dotted line, large dampener (V_l = 9.4 cm³)-green point dashed line. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)