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Lee's Disc Apparatus

Model: HO-ED-M-03

Thermal conductivity is the property of a material that indicates its ability to conduct heat. Conduction takes place if there exists a temperature gradient in a solid (or stationary Fluid) medium. Energy is transferred from more energetic to less energetic molecules when neighboringmolecules collide. Conductive heat flow occurs in the direction of the decreasing temperature because higher temperature is associated with higher molecular energy. Holmarc's Lee's Disc Apparatus (Model: HO-ED-M-03) is designed for the measurement of thermal conductivity in bad conductors.

Lee's Disc Apparatus comprises of a brass disc resting on another slab of the same dimension with special heating coil. Both metallic discs have radial holes for the sensitive thermistors. Material under test is placed in between two discs. The heater is turned on and the apparatus is left idle until the temperature gets stabilized. At this point the heat energy passing through the heat sample will be exactly equal to the heat flowing out of the lower block.

Maximum temperature the disc can achieve during the experiment is around 60 degree Celsius to make it safe for handling with even bare hands. Similarly, operating voltage for heating coil sandwiched between the discs is fixed as 50V for safety. The temperature sensors used are highly sensitive and accurate with least count as low as 0.2 degree Celsius. Front panel is equipped with digital display and keyboard for user friendly operation.

This Apparatus provides the facility for performing experiments using different kinds of sample materials. The front panel includes LCD display and keyboard for readouts and settings.

There are three operation modes for this Equipment - Manual mode, Auto mode and PC mode. In manual mode, the user can calculate thermal conductivity using the acquired data manually. In auto mode, the user can retrieve result directly from the system once the temperature stabilized. In PC mode, one can monitor progress of the experiment through a computer and can calculate thermal conductivity with the help of Holmarc’s software. This diversity of usage makes the equipment user friendly.



Caution : Do NOT touch the discs with bare hands during the time of heating. High temperature can make severe burns in the body. Try to use gloves for handling the discs.



Feasible Experiments

    To determine thermal conductivity of bad conductors (Glass, Nylon, Plywood, etc.) in the form of a disc using Lee's method.

Thermal conductivity,

k  =  (Mc dT / dt )  /  (πr2 (T2 - T3) )  ×  (r + 2h) d / 2( r + h) W  /  mK-1

Where,

M = Mass of the metallic disc

c = Specific heat capacity of the metallic disc

h = Height of the metallic disc

r = Radius of the metallic disc

dT / dt = Rate of cooling of the metallic disc at T2

d = Thickness of the sample

T2 - T3 = Steady temperatures recorded at T2 and T3 respectively



Features

    New and integrated design

    Measure thermal conductivity of different materials

    LCD display readout for accurate measurement

    Manual and auto measurements using a single system

    Easy to use equipment
Learn out

    Thermal conductivity

    Heat transfer

    Specific heat capacity
Scope of Supply


    Lees Disc Control Unit

Model No: ED-M-03-LDCU
Input
:
230V 5Amp AC
Quantity
:
1 no.
Lees Disc Control Unit

    Heating Unit with Disc

Model No: ED-M-03-HUD
Operating Voltage (Manual Model)
:
50 V
Quantity
:
1 no.

Heating Unit with Disc

    Brass Disc

Model No: ED-M-03-BD
Material
:
Cartridge Brass
Diameter
:
76.2 mm
Height
:
(Block, B1) & 8 mm (Block B4)
Quantity
:
1 Number each


Brass Disc

    AC Power Cord

Model No: ED-M-03-APC
Type
:
3 core 3 Pin
Quantity
:
1 no.
AC Power Code

    Test Samples

Model No: ED-M-03-TS
Material
:
Borofloat glass, Teflon, Nylon
Quantity
:
1no. each

Test Samples

    Accessories

RS 232 PC cable and connector
Heat Sink Compound
User Manual
software CD



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