Comparators and their working principle

1. comparators
Presenting by
PRANEETH REDDY SHERI

2. Comparator
Comparators are the instruments that are used to find out unknown size with known
reference Designed in a such a way that a small movement at measuring end is converted
into large movement in reading end Which means comparators are used to measure a
small difference in sizes by comparing them

3. Types of Comparator
1. Mechanical Comparator
2. Electrical Comparator
3. Pneumatic Comparator
4. High Magnification gauge Comparator
5. Fluid displacement Comparator

4. High Magnification Gauge Comparator
There are two types of HMGC
 Brook’s Level Comparator
 Eden Rolt Comparator

5. Important note
 It should be noted that all type of comparators are comparing instruments.
 They are not Measuring Instruments it means there are only used for comprising of a
unknown size with the Known reference size

6. Our Topic
 We are bound to discuss the Following comparator
Eden Rolt Comparator

7. Principle
 It works on two main principle
 Mechanical Magnification ( By lever Mechanism )
 Optical Magnification ( Optical Shadow Mechanism)

8. Components of ER Comparator
 Anvil ( Both Movable and Non-Movable)
 Block ( Both Moving and Non-Moving )
 Steel Strips
 Pointer Strips
 Pointer Arm

10. Function of Component
Anvil
 Purpose of Fixed Anvil is to provide the grip for our work-part
 Movable anvil is used to play a part in providing Mechanical Magnification
Strips
 The strips are used to provide displacement and cause of deflection of Pointer Arm.
Block
 Causes twisting of a lever.

11. Optical Shadow Mechanism
(Component)
 Lamp
 Prism
 Spider web
 Lens
 Mirror
 Scale

12. How it Works ?????????????

13. Mechanical Mechanism

14. Optical Shadow Projection

15. Specification
 Each division of its scale represents 0.0002 mm so that by estimation it is possible to read
0.00002 mm.
 This comparator is capable of calibrating gauges up to 25 mm.
 Mechanical Magnification can be with in the range of 300-400x(with lever about 200mm)
 Optical Magnification can be 60x
 So the total Magnification can be obtained by this comparator is 20,000x

16. Manufacturing ease…………..
 The space between strips and length of lever and rest of accuracy are not required to be
much Precise.
Because
 That can be compensated by the facility of calibration.
 Example
Gauge block (known size)..

17. Method of Calibration
 Place Gauge of known size
 Marks it reading as a reference( ‘0’ )
 Remove Gauge
 Place another unknown size gauge
 Check out the reading
 If the scale gives value beyond the ‘0’ then add value to reference
 If a scale gives reading before ‘0’ then we subtract from reference.

18. • THANK YOU