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

Micromachines ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 653 ◽  
Author(s):  
Zhang ◽  
Zhang
Keyword(s):  
Flow Control ◽  
Flow Rate ◽  
Low Cost ◽  
Flow Characteristics ◽  
Check Valve ◽  
Maximum Pressure ◽  
Channel Height ◽  
Fluidic Channel ◽  
Constant Flow Rate ◽  
Passive Flow

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.

Flow Control in a Laminate Capillary-Driven Microfluidic Device

2020 ◽  
Author(s):  
Ilhoon Jang ◽  
David S. Dandy ◽  
Brian J. Geiss ◽  
Charles Henry ◽  
Hyunwoong Kang ◽  
...  
Keyword(s):  
Flow Control ◽  
Microfluidic Device ◽  
Flow Rate ◽  
Low Cost ◽  
Channel Height ◽  
Control Methods ◽  
Inlet Channel ◽  
Passive Flow Control ◽  
Passive Flow ◽  
Fluid Properties

Capillary-driven microfluidic devices are of significant interest for on-site analysis because they do not require external pumps and can be made from inexpensive materials. Among capillary-driven devices, those made from paper and polyester film are among the most common and have been used in a wide array of applications. However, since capillary forces are the only driving force, flow is difficult to control, and passive flow control methods such as changing the geometry must be used to accomplish various analytical applications. This study presents several new flow control methods that can be utilized in a laminate capillary-driven microfluidic device to increase available functionality. First, we introduce push and burst valve systems that can stop and start flow. These valves can be opened by either pressing the channel or inflowing other fluids to the valve region. Next, we propose flow control methods for Y-shaped channels that enable more functions. In one example, we demonstrate the ability to accurately control concentration and in a second example, flow rate in the main channel is controlled by adjusting the geometry of the inlet channel. Finally, the flow rate in the Y-shaped device as a function of channel height and fluid properties such as viscosity and surface tension was examined. As in previous studies on capillary-driven channels, the flow rate was affected by each parameter. The fluidic control tools presented here will enable new designs and functions for low cost point of need assays across a variety of fields.

Flow Control in a Laminate Capillary-Driven Microfluidic Device

2020 ◽  
Author(s):  
Ilhoon Jang ◽  
David S. Dandy ◽  
Brian J. Geiss ◽  
Charles Henry ◽  
Hyunwoong Kang ◽  
...  
Keyword(s):  
Flow Control ◽  
Microfluidic Device ◽  
Flow Rate ◽  
Low Cost ◽  
Channel Height ◽  
Control Methods ◽  
Inlet Channel ◽  
Passive Flow Control ◽  
Passive Flow ◽  
Fluid Properties

Capillary-driven microfluidic devices are of significant interest for on-site analysis because they do not require external pumps and can be made from inexpensive materials. Among capillary-driven devices, those made from paper and polyester film are among the most common and have been used in a wide array of applications. However, since capillary forces are the only driving force, flow is difficult to control, and passive flow control methods such as changing the geometry must be used to accomplish various analytical applications. This study presents several new flow control methods that can be utilized in a laminate capillary-driven microfluidic device to increase available functionality. First, we introduce push and burst valve systems that can stop and start flow. These valves can be opened by either pressing the channel or inflowing other fluids to the valve region. Next, we propose flow control methods for Y-shaped channels that enable more functions. In one example, we demonstrate the ability to accurately control concentration and in a second example, flow rate in the main channel is controlled by adjusting the geometry of the inlet channel. Finally, the flow rate in the Y-shaped device as a function of channel height and fluid properties such as viscosity and surface tension was examined. As in previous studies on capillary-driven channels, the flow rate was affected by each parameter. The fluidic control tools presented here will enable new designs and functions for low cost point of need assays across a variety of fields.

Investigation of suction flow characteristic in the inertance hydraulic converters for efficiency improvement

2021 ◽  
pp. 095965182110248
Author(s):  
Xiaoming Chen ◽  
Yuchuan Zhu ◽  
Travis Wiens ◽  
Doug Bitner ◽  
Minghao Tai ◽  
...  
Keyword(s):  
Flow Rate ◽  
Flow Characteristic ◽  
Performance Indicator ◽  
Flow Characteristics ◽  
Check Valve ◽  
Analytical Models ◽  
Switching Frequency ◽  
Experimental Measurements ◽  
Efficiency Improvement ◽  
Suction Flow

The inertance hydraulic converter relies on fluid inertance to modulate flow or pressure and is considered to be a competitive alternative to the conventional proportional hydraulic system due to its potential advantage in efficiency. As the quantification of fluid inertance, the suction flow characteristic is the crucial performance indicator for efficiency improvement. To explore the discrepancy between the passive inertance hydraulic converter featured by the check valve and the active inertance hydraulic converter driven by an equivalent 2/3 way fast switching valve in regard to suction flow characteristics, analytical models of the inertance hydraulic converters were established in MATLAB/Simulink. The validated models of the respective suction components were incorporated in the overall analytical models and their suction flow characteristics were theoretically and experimentally discussed. The analytical predictions and experimental measurements for the current configurations indicated that the active inertance hydraulic converter yields a larger transient suction flow rate than that of the passive inertance hydraulic converter due to the difference of the respective suction components. The suction flow characteristic can be modulated using the supply pressure and duty cycle, which was confirmed by experimental measurements. In addition, the suction flow characteristics are heavily affected by the resistance of the suction flow passage and switching frequency. There is a compromise between the resistance and switching frequency for inertance hydraulic converters to achieve large suction flow rate.

scholarly journals Analysis of the Binding of Analyte-Receptor in a Micro-Fluidic Channel for a Biosensor Based on Brownian Motion

Micromachines ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 570
Author(s):  
Sunghak Choi ◽  
Woo Il Lee ◽  
Gyu Hee Lee ◽  
Yeong-Eun Yoo
Keyword(s):  
Mathematical Model ◽  
Brownian Motion ◽  
Flow Rate ◽  
Channel Height ◽  
Micro Channel ◽  
Analyte Concentration ◽  
Fluidic Channel ◽  
Binding Characteristics ◽  
Detection Characteristics ◽  
The Mathematical Model

This study experimentally analyses the binding characteristics of analytes mixed in liquid samples flowing along a micro-channel to the receptor fixed on the wall of the micro-channel to provide design tools and data for a microfluidic-based biosensor. The binding or detection characteristics are analyzed experimentally by counting the number of analytes bound to the receptor, with sample analyte concentration, sample flow rate, and the position of the receptor along the micro-channel length as the main variables. A mathematical model is also proposed to predict the number of analytes transported and bound to the receptor based on a probability density function for Brownian motion. The coefficient in the mathematical model is obtained by using a dimensionless mathematical model and the experimental results. The coefficient remains valid for all different conditions of the sample analyte concentration, flow rate, and the position of the receptor, which implies the possibility of deriving a generalized model. Based on the mathematical model derived from mathematical and experimental analysis on the detection characteristics of the microfluidic-based biosensor depending on previously mentioned variables and the height of the micro-channel, this study suggests a design for a microfluidic-based biosensor by predicting the binding efficiency according to the channel height. The results show the binding efficiency increases as the flow rate decreases and as the receptor is placed closer to the sample-injecting inlet, but is unaffected by sample concentration.

Development of Novel Particle Excitation Flow Control Valve for Stable Flow Characteristics

2016 ◽  
Vol 10 (4) ◽  
pp. 540-548 ◽  
Author(s):  
Daisuke Hirooka ◽  
◽  
Tomomi Yamaguchi ◽  
Naomichi Furushiro ◽  
Koichi Suzumori ◽  
...  
Keyword(s):  
Flow Control ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Control Valve ◽  
Flow Control Valve ◽  
Different Types ◽  
Valve Opening ◽  
Working Principle ◽  
Stable Flow ◽  
Air Flow Control

The authors have previously developed a compact, light-weight air flow control valve, which realizes continuous flow control. The vibration produced by a piezoelectric device (PZT) was used to excite particles confined in a flow channel to control the valve opening for the developed control valve. Therefore, the voltage applied to the PZT can be changed to continuously control the flow rate. A new working principle was developed for the control valve to stabilize flow rate characteristics. Different types of particles were used to change the valve opening condition. A prototype was manufactured to demonstrate the effectiveness of the control valve.

Bubble Removal in Microfluidic Devices Using Nanofibrous Membranes

2014 ◽  
Author(s):  
Ravindra Vundavilli ◽  
Jeff Darabi
Keyword(s):  
Pore Size ◽  
Flow Rate ◽  
Liquid Flow ◽  
Liquid Flow Rate ◽  
Microfluidic Devices ◽  
Channel Height ◽  
Hydrophobic Membrane ◽  
Fluidic Channel ◽  
Nanofibrous Membranes ◽  
Bubble Removal

This paper presents an experimental study to determine bubble removal characteristics of nanofibrous membranes in microfluidic devices. It is well known that the presence of gas bubbles in fluidic channels can cause significant flow disturbances and adversely affect the overall performance and operation of microfluidic devices. In this study, a microfluidic device is designed and fabricated to generate and extract bubbles from a microfluidic channel. A T-junction is used to produce controllable bubbles at the entrance of fluidic channel. The generated bubbles are then transported to a bubble removal region and vented through a highly porous hydrophobic membrane. Four different hydrophobic PTFE membranes with different pore sizes ranging from 0.45 to 3 μm were used to permeate air bubbles. The fluidic channel width was 500 μm and channel height ranged from 100 to 300 μm. The effects of pore size, channel height, and liquid flow rate on the bubble removal rate are investigated. The results reveal that the rate of bubble removal increases with increasing the pore size and channel height but decreases with increasing the liquid flow rate.

The Fabrication and Test of a Phase-Change Micropump

2001 ◽  
Author(s):  
Hyeun Joong Yoon ◽  
Woo Young Sim ◽  
Sang Sik Yang
Keyword(s):  
Phase Change ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Check Valve ◽  
Maximum Flow ◽  
Input Voltage ◽  
Working Fluid ◽  
Duty Ratio ◽  
Boron Diffusion ◽  
Change Type

Abstract This paper presents the fabrication and test of a phase-change type micropump with two aluminum flap valves. This micropump consists of a pair of Al flap valves and a phase-change type actuator. The actuator is composed of a heater, a silicone rubber diaphragm and a working fluid chamber. The diaphragm is actuated by the vaporization and the condensation of the working fluid. The micropump is fabricated by the anisotropic etching, the boron diffusion and the metal evaporation. The dimension of the micropump is 8.5 mm × 5 mm × 1.7 mm. The forward and the backward flow characteristics of the flap valve illustrate the appropriateness as a check valve. Also, the flow rate of the micropump is measured. When the square wave input voltage of 10 V is applied to the heater, the maximum flow rate of the micropump is 6.1 μl/min at 0.5 Hz and the duty ratio of 60% for zero pressure difference.

Motion of a deformable capsule through a hyperbolic constriction

1994 ◽  
Vol 279 ◽  
pp. 135-163 ◽  
Author(s):  
Anne Leyrat-Maurin ◽  
Dominique Barthes-Biesel
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Stokes Equations ◽  
Flow Characteristics ◽  
Quantitative Information ◽  
Maximum Energy ◽  
Centre Of Mass ◽  
Intrinsic Properties ◽  
Constant Flow Rate ◽  
Reynolds Number Flow

A model for the low-Reynolds-number flow of a capsule through a constriction is developed for either constant-flow-rate or constant-pressure-drop conditions. Such a model is necessary to infer quantitative information on the intrinsic properties of capsules from filtration experiments conducted on a dilute suspension of such particles. A spherical capsule, surrounded by an infinitely thin Mooney-Rivlin membrane, is suspended on the axis of a hyperbolic constriction. This configuration is fully axisymmetric and allows the entry and exit phenomena through the pore to be modelled. An integral formulation of the Stokes equations describing the flow in the internal and external domains is developed. It provides a representation of the velocity at any location in the flow as a function of the unknown forces exerted by the boundaries on the fluids. The problem is solved by a collocation technique in the case where the internal and external viscosities are equal. Microscopic quantities (instantaneous geometry, centre of mass velocity, elastic tensions in the membrane) as well as macroscopic quantities (entry time, additional pressure drop or flow rate reduction) are predicted as a function of the capsule intrinsic properties and flow characteristics. The results obtained for a capsule whose initial diameter is larger than that of the constriction throat show that the maximum energy expenditure occurs when the particle centre of mass is still upstream of the throat (typically 1 diameter away), and is thus due to the entry process. For large enough or rigid enough capsules, the model predicts entrance or exit plugging, in agreement with experimental observations. It is then possible to correlate the variation of the pore hydraulic resistance to the flow capillary number (ratio of viscous to elastic forces) and to the size ratio between the pore and the capsule.

Unsaturated flow characteristics in dual-scale fibre fabrics at one-dimensional constant flow rate

2016 ◽  
Vol 23 (6) ◽  
pp. 617-624
Author(s):  
Yan Shilin ◽  
Yan Fei ◽  
Li Dequan ◽  
Li Yongjing
Keyword(s):  
Flow Rate ◽  
Unsaturated Flow ◽  
Flow Characteristics ◽  
Constant Flow ◽  
One Dimensional ◽  
Constant Flow Rate ◽  
Liquid Composite Moulding ◽  
Mould Filling ◽  
Set Up ◽  
Dual Scale

AbstractFibre fabrics in liquid composite moulding can be considered as dual-scale porous media. In different gap scales, an unsaturated flow is produced during the mould filling process. This particular flow behaviour deviates from the traditional Darcy’s law, which is used to calculate the filling pressure and will cause errors. To prove the mechanism of this unsaturated flow, an experimental device was set up with a one-dimensional constant flow rate. The influencing factors, such as injected media, flow velocity and fibre fabric, were investigated in this study. Based on the experimental data, several useful conclusions were drawn, providing good references for optimising the process parameters and controlling the product quality.

Aeration Apparatus Converts Bin From Funnel-Flow to Mass-Flow Characteristics

1973 ◽  
Vol 95 (1) ◽  
pp. 37-41 ◽  
Author(s):  
R. B. Emery
Keyword(s):  
Flow Control ◽  
Mass Flow ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Storage Space ◽  
Flow Problems ◽  
Fine Powders ◽  
Bulk Solid ◽  
Discharge Rates ◽  
Funnel Flow

A properly designed hopper provides cost control through increased unloading reliability, improved storage space utilization, steadier discharge rates, and improved blending of discharged materials. Hoppers have been designed to provide these advantages by providing mass-flow characteristics without application of auxiliary flow promoting devices. Many hoppers are not designed for proper flow. In some cases, limitations on head room, flow rate requirements, or bulk solid characteristics present barriers to design goals of proper flow. Application of aeration can alleviate flow problems in existing hoppers without major changes in hopper configuration and, in addition, it can be helpful in reducing required head room, promoting flow control, and handling some very fine powders. An application of such an aerating device to improve the flow characteristics of fine powders from funnel-flow to mass-flow is discussed in this paper.

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