1.
CONTENTS

2.
An instrument for
measuring the velocity
of flow of a fluid (as blood)
in a tube or pipe
Blood flow is a time
varying quantity and
important
parameter to be
measured

3.
Need For Blood Flowmeter ?
Provides vital
info about the
oxygen and
nutrients to
various parts of
the body
The average
velocities of
blood flow vary
over a wide
range depending
on diameter of
blood vessel.
Inspection for
block in blood
flow.
Testing artificial
blood vessels
during organ
transplantation.

4.
Measurement Techniques
Electromagnetic
Blood Flow meter
Ultrasonic Blood Flow
Meter
Laser Doppler Blood
Flow Meter

5.
1.Electromagnetic Blood Flow Meter
Works based on the principle of
electromagnetic induction
“The voltage induced in a conductor
moving in a magnetic field is
proportional to the velocity of the
conductor”
The conductive blood is the moving
conductor
It is invasive technique
Principle Diagram

6.
Electromagnetic Blood Flow Meter

7.
Electromagnetic Blood Flow Meter
A permanent magnet or electromagnet positioned around the
blood vessel generates a magnetic field perpendicular to the
direction of the flow of the blood.
Voltage induced in the moving blood column is measured with
stationary electrodes located on opposite sides of the blood
vessel and perpendicular to the direction of the magnetic field.
This method requires that the blood vessel be exposed so
that the flow head or the measuring probe can be put across
it.

8.
2.Ultrasonic Blood Flow Meter
(principle)
Ultrasonic waves are
ideal for non-invasive
sensing
A moving blood cell
changes the frequency
of sonic waves before
and after it.
The sonic waves
compress before an
object and spread out
behind it.
This frequency shift is
the Doppler Effect

9.
Ultrasonic Blood Flow Meter
These devices include a transmitter and
receiver.
Reflective material bounces the transmitted
wave back into the receiver.
The received wave has a frequency shift. The
source frequency is lowered twice.
The first shift occurs when the transmitted
wave hits the object and the second shift
occurs when the resulting wave comes back .

10.
Ultrasonic Blood Flow Meter

11.
3.Laser Doppler Blood Flow Meter
Principle of laser Doppler Flowmetry
Red light is emitted from a light source; if the light beam is scattered-off of stationary tissue or cells, there is
no shift in the light spectrum. If, however, the light hits a moving cell in a blood vessel there is a shift in the
light spectrum of the scattered light according to the Doppler flowmetry

12.
 American National Standards Institute (ANSI) Definition
o A device which provides a usable output in response to a specified
measured input.
 A sensor acquires a physical parameter and converts it into a signal suitable
for processing (e.g. optical, electrical, mechanical)
Physical
Quantity
sensor
Electrical
Quantity

13.
Flexible Sensors
(New Technology)

14.
University of Illinois at Urbana-
Champaign has developed a
flexible electronic sensor that
can measure blood flow on top
of the skin or, can possibly be
implanted onto the tissues
themselves
Flexible sensor that can
stick onto the skin like a
temporary tatooo

15.
Flexible sensor
The devices are made from a thin array of
metallic wires that are oriented around a
central sensor and map blood flow as well as
pick up on the slight temperature increase that
each pulse of blood brings
They are coated in a thin layer of silicone, so
they are flexible and can stick to the skin like
temporary tattoos
Can determine temprature to the third
decimal place and accurately track the
change at that level, it provides a lot of deep
insight into physiological health
Could potentially be used for lie detector

16.
Blood Flow
Measurement
Devices Market, by
Applications
Gastroenterology
Diabetes Research
Dermatology
Peripheral Vascular
Diseases
Heart attack