Microfluidic Passive Flow Regulatory Device with an Integrated Check Valve for Enhanced Flow Control

Abstract

A passive microvalve has appealing advantages in cost-effective and miniaturized microfluidic applications. In this work, we present a passive flow regulatory device for enhanced flow control in a microfluidic environment. The device was integrated with two functional elements, including a flow regulating valve and a flow check valve. Importantly, the flow regulating valve could maintain a stable flow rate over a threshold liquid pressure, and the flow check valve enabled effective liquid on/off control, thus accurate forward flow without any backward leakage was achieved. The flow performance of the flow regulating valve was analyzed through 3D FSI (Fluid-Structure Interaction) simulation, and several key parameters (i.e., fluidic channel height and width, control channel length, and Young’s modulus) were found to influence valve flow rate directly. To examine the flow characteristics of the device, we fabricated a prototype using 3D printing and UV laser cutting technologies, and the flow rates of the prototype under varied test pressures were measured in forward and reverse modes, respectively. Experimental results showed that nearly a constant flow rate of 0.42 ± 0.02 mL s−1 was achieved in the forward mode at an inlet pressure range of 70 kPa to 130 kPa, and liquid flow was totally stopped in the reverse mode at a maximum pressure of 200 kPa. The proposed microfluidic flow regulatory device could be employed for accurate flow control in low-cost and portable Lab-on-a-Chip (LoC) applications.

A New Non-Invasive Air-Based Actuator for Characterizing and Testing MEMS Devices

“…The results showed that a force of 15.7 nN could be generated on a circular surface of R = 5 µm when air velocity is 60 m/s, and the Z is 25 µm. This phenomenon also was reported by Jungchul Lee et al [55,56], in which they asserted that the effective flow field depends on the separation field, which is the distance between the nozzle exit and the effective area. However, in the same distance of nozzle exit, the liquid jet is focused, and the nitrogen will flow on the surface in a cone-shaped area.…”

“…AbFM can be applied to new emerging microfluidic and micro-pump systems that need fluidic force to check their working conditions and check the inside material functions. Microfluidic passive flow regulatory devices [55], integrated peristaltic pumps, [56], and compact hollow structures for microfluidic pumping [57] are three important examples of a potential target of AbFM use for testing and characterizing. AbFM method is a promising method for future testing and characterization of MEMS devices; however, there are some important concerns that need to be addressed in future contributions.…”

Microfluidic Passive Valve with Ultra-Low Threshold Pressure for High-Throughput Liquid Delivery

“…In comparison to the active valve, a passive valve doesn't require any external power, and it regulates the flow rate of liquid through autonomous adjustment of flow resistance. In addition, as it is capable of realizing self-adaptive resistance variations which completely compensate the fluidic pressure variations, a constant flow rate can, as a result, be achieved by the valve with a pre-determined threshold pressure [27][28][29]. Cousseau et al developed a silicon membrane valve for drug delivery [30].…”

Analysis of Stiffness Effect on Valve Behavior of a Reciprocating Pump Operated by Piezoelectric Elements

“…The reciprocating pump that uses such a piezoelectric element is composed of a piston, a chamber, check valves, and other components. Here, the check valve plays an important role in giving the flow direction in the pump, and studies have been conducted on various types of check valves such as balls, membranes, cantilevers, wheels, and moving elements [ 5 , 14 , 15 , 16 , 17 , 18 , 19 ]. Van Lintel investigated the passive valve that controls the pressure and the flow rate of the pump in 1988 to increase the performance of the pump [ 20 ], and cantilever valves are widely used in small pumps due to their simple structure and easy fabrication.…”