Viscosity determination device

1. ENGLER’S
VISCOMETER
MUNKHBAYAR MUNKHSAIKHAN
244.19E

2. What is Viscosity
Newton's Law of Viscosity states
that the shear stress (τ) on a fluid
element layer is directly
proportional to the rate of shear
strain (velocity gradient). The
constant of proportionality is
called the co-efficient viscosity.

3. Dynamic viscosity
 Constant of proportionality and is
known as the coefficient of
dynamic viscosity
Kinematic viscosity
 It is defined as the ratio between
the dynamic viscosity and density
of fluid.
[Pa*sec] [ /sec]
1 Pa s = 10 P
1000 mPa s = 10 P
1 mPa s = 0.01 P
1 mPa s = 1 cP
Dynamic viscosity is the quantitative
expression of fluid's resistance to flow,
while Kinematic viscosity is the ratio of the
fluid's viscous force to the inertial force.

4. What is Viscometer?
 A viscometer (also
called viscosimeter)
is an instrument
used to measure
the viscosity of
a fluid. Viscometers
only measure under
one flow condition.

5. Let's go back to main
topic
 Engler viscometer is used for
measuring the viscosity of
lubricating oils. It measured the
viscosity of liquids by the number
of drops. This idea was the basis
for the Engler viscometer. The
device consists of an oil cup with a
spherical bottom.

6. Engler degree
 In Great Britain, a scale used as a
conventional measure of kinematic
viscosity. Symbol, E or °E. Engler scale
is based on comparing a flow of the
substance being tested to the flow of
another substance, namely water.
 Viscosity in Engler degrees is the ratio
of the time of flow of 200 cubic
centimeters of the oil whose viscosity
is being measured, to the time of flow
of 200 cubic centimeters of water at
the same temperature (usually 20°C
but sometimes 50°C or 100°C) in a
standardized Engler viscosity meter.
 The Engler degree is named for Carl
Oswald Viktor Engler (1842-1925).

7.  The device consists of an oil
cup with a spherical bottom.
In its center there is an oil
tube with a plug at the top.
On the inner surface of the oil
cup there are three marks.
The liquid is poured up to the
200 cm3 mark.
 Viscous fluids can be
influenced by ambient
temperature. To compensate,
the cup is surrounded with a
thermostat with a
thermometer.

8. There are lot of different kinds of viscometers, this
module will focus on the three most common types.
Viscometer
Capillary
(Engler
viscometer)
Rotational Falling ball

9. Capillary Viscometers
Capillary viscometers measure viscosity by monitoring fluid flow through very
narrow glass tubes.
In a capillary viscometer, a liquid is drained or forced through a fine-bore tube ,
and the viscosity is determined from the measured flow rate, applied pressure,
and tube dimensions. A variety of capillary viscometers is shown below.
For a given pressure drop, the time it takes for a fluid volume to flow a certain
distance through a tube is a function of the fluid's resistance to flow. A more
viscous fluid will take a longer time to travel that distance.

10. Equipment
Design
 To determine viscosity, the
time for a given volume of
fluid to travel a distance
through the capillary tube
(either due to gravity or a
driving force) is measured.
 Capillary viscometers are
calibrated with standard
fluids of known viscosities.
The viscosity of a fluid can
be computed by
multiplying the time
required for flow by a
calibration constant.

11. Usage Examples
 Capillary viscometers are used to
measure the viscosity of a wide
range of diverse fluids. Common
examples include petroleum
products, lubricants, adhesives,
and sealants.
 Different models of capillary
viscometers are used to measure
specific types of fluids, such as
opaque viscometers for darker
fluids, or high-viscosity
viscometers for fluids with
particularly high viscosities.

12. Advantages
• Measure precise viscosities for many diverse fluids
• Small and portable
• Can use wide variety of capillary tubes on the same viscometer
Disadvantages
• No single tube is suitable for all viscosities
• Basic models can only be used for translucent fluids
• Difficult to clean capillary tubes

13. Thank you for your
attention!