Group 3: Micropumps and Microvalves

GROUP 3
MICROPUMPS AND
MICROVALVES
GROUP MEMBERS
 MBANGA SAHR C17131010B

 ZVAWANDA NYASHA C17131953S
 DHLIWAYO JENNIPHER N C17131310I
 SEREMANI MARTIN C17130913W
 ZHOU MUFARO C17131611N
OUTLINE
 Introduction
 Micro pumps
 Micro valves
 Conclusion
INTRODUCTION
 Microvalves and micropumps form the foundation

of many different microfluid systems.
 Microvalves control routing,timing and separation
of fluids within a microfluidic device.
 Micropumps on the other hand are responsipble
for generating temperal and volumetric fluid
movement on-chip and are used to reduce the
amount of external hardware necessary to operate
a microfluidic device.
MICROPUMPS
• Like microvalves, micropumps are essential components to
controlling and modulating fluid flow in microfluidic networks.
• Micropumps can be generally classified into two categories—
active and passive.
• While flow rate is a measure of individual pump performance,
it is not a useful metric when comparing pumps of different
designs.
PUMP BASIC OPERATION
GENERAL TYPES OF
MICROPUMPS
 BUBBLE PUMPS
 DIFUSSER PUMPS
 MEMBRANE PUMPS (most common)
 ROTARY PUMPS
 ELECTROHYDRODYNAMIC PUMPS
 ELECTROOSMOTIC/ ELECTROPHORETIC
PUMPS
 ULTRASONIC PUMPS
 OPTICAL PUMPS
BUBBLE/DIFUSSER PUMP
 The formation and collapse of a bubble in the
liquid is used to drive the flow of the liquid
 Allows for a valve-less diffuser design
 Greatly enhances mixing of the constituent
phases
 Flow rate in the range of 4-5 μL/sec for 250-
400Hz
http://www.me.berkeley.edu/~lwlin/papers/2002Tsai.pdf
ROTARY PUMPS
 Very rare and not commonly researched
 Extremely complicated fabrication
 High susceptibility to failure
 Very precise control of the fluid flow and
dprocessirection
 Good for transporting high impurity liquids
http://cmmt.gatech.edu/Mark/Publications/Allen_95_Fluid_Micropumps_Rot_Mag_Actu.pdf
MEMBRANE PUMPS
 Membrane pumps often consists of two check
valves and a chamber with a moveable membrane.
 By some mechanism,the membrane can be
actuated to change the volume of the chamber.
 Because the check valve can be opened only in
one direction for each circle some fluid will be
moved from inlet to outlet.
 Examples of membrane pumps are
thermopneumatic membrane pump,electrostatic
membrane pump,piezoelectric membrane pump.
MEMBRANE PUMPS
 PIEZOELECTRIC
 ELECTROMAGNETIC
 ELECTROSTATIC
 THERMAL NEUMATIC
 THERMAL GEL
 SHAPE MEMORY ALLOY
PRINCIPLE OF OPERATION
 Electrostatic actuation of a diaphram
 A silicon diaphram forms an electrode of a
capacitor.
 Motion of a diaphram changes the pressure in the
chamber.
MEMBRANE PUMPS
 Method of displacing the membrane
 Magnetically
 Electrostatically
 With a piezoelectric
 Thermally (SMA and thermopneumatically)
 Sensitive to blockage by particulates in the fluid
 Flow rate in the range of 100-10000 μL/sec
http://ej.iop.org/links/60/IYwveEquvuX,ovtuKcQOMw/jm8218.pdf http://www.ajou.ac.kr/~mems/proj-1-1.htm
Thermal pneumatic
 The pressure of air in a cavity, raised by resistive heating,

deflects a thin silicon membrane.
MICROVALVES
• Microvalves allow the user to control fluid flow in a
microchannel by varying a given macroscopic parameter.
VALVE CLASSIFICATION
 Non-moving valve
 Passive valves
 Actuated/ Active valves
NON_MOVING VALVES
 Diffuser Valve
 Provides
directional
resistance
http://www.cr.org/publications/MSM2001/html/T67.02.html
PASSIVE VALVES
 Cantilever
 Disc
 Membrane
Shoji, Journal of micromechanics and microengineering 1994

PASSIVE VALVES (con’t)
 Piston
 Gas controlled
Quake, Science 2000

ACTIVE VALVES
 Valve types based on actuation
 Electromagnetic
 Piezoelectric
 Pneumatic
 Electrokinetic
• The valves can be actuated mechanically , pneumatically
electrokinetically, by phase changes, or by introduction of external force.
• Electrokinetic valves operate in continuous flow systems, serving as a
fluid “router” that uses electroosmotic flow to switch fluids from one
channel to another.
• Pneumatic valves typically rely on a flexible membrane to control the flow
pattern in the flow channel.

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GROUP 3

 MBANGA SAHR C17131010B

 Microvalves and micropumps form the foundation

 The pressure of air in a cavity, raised by resistive heating,

Shoji, Journal of micromechanics and microengineering 1994

Quake, Science 2000

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