another ppt for a class presentation . I admit it is a bit incomplete but this is all I got as a topic for explanation . I hope you guys gain from it !
2. Common Sources of Errors are:
Ambient temperature Effect
Head or Elevation Efffect
Barometric Effect
Immersion Effect
Radiation Effect
3. The effect taking place due to the
exposure of the bourdan tube and the
capillary tube to the surroundings .
Being exposed to the surroundings causes
them to be subjected to variable temp.
widely different to that of the bulb .
4. Using Large Bulb :
From the equation we can clearly see that
the use of a larger bulb will reduce the
error
Case Compensation :
A bimetallic strip or secondary bourdan
tube is used to counter the deflection in
the main bourdan tube in the opposite
direction .
5. Full Compensation :
The only new difference id that even a capillary
tube has been attached to counter the effects
.
Using Self Compensating Capillary :
In this case the cross section of the capillary is
made into a annulus which has a special alloy
wire in its whole length to counter the
capillary expansion.
6.
7.
8.
9.
10. This is the error caused due the elevation
of the bulb from the level of the bourdan
tube . Due to the difference in height a
pressure head is created which causes
error in the temperature reading .
11.
12. The tip travel of bourdon tube is due to
pressure difference between atmosphere
and filled system pressure . So if there is
any variation in atmosphere pressure from
designed pressure , the bourdon tip travels
and causes an error reading .
The equation shown by me is used to
calculate the error .
13. This error is caused to the improper
immersion or insulation of head of bulb .
14. This error occurs due to temperature
difference between the bulb and solid
bodies around it .
Dip Effect : In case of a metallic bulb of
mercury filled system, the metallic bulb
expands before expansion of mercury ,
hence volume of bulb is increased and
pressure reduces . So in short respose of
thermometer is slowed down .
