chadalawada ramanamma engineering college · 2018-09-18 · 9 study and calibration of a rotometer...

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METROLOGY AND MEASUREMENTS LABORATORY MANUAL

Subject CodeSubject CodeSubject CodeSubject Code : : : : 15A015A015A015A03711371137113711

RegulationsRegulationsRegulationsRegulations : : : : JNTUAJNTUAJNTUAJNTUA –––– R1R1R1R15555

ClassClassClassClass : : : : VVVVIIIIIIII Semester (Semester (Semester (Semester (MMMME)E)E)E)

CHADALAWADA RAMANAMMA ENGINEERING COLLEGE (AUTONOMOUS)

Chadalawada Nagar, Renigunta Road, Tirupati – 517 506

Department of Mechanical Engineering

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CHADALAWADA RAMANAMMA ENGINEERING COLLEGE (AUTONOMOUS)

Chadalawada Nagar, Renigunta Road, Tirupati – 517 506

Department of Mechanical Engineering

INDEX

S. No Name of the Experiment Page No

1 Measurement of bores by internal micrometers and dial bore indicators. 3-8

2 Use of gear teeth vernier calipers and checking the chordal addendum and choral height of spur gear.

9-15

3 Alignment test on the lathe and milling machine 16-28

4 Study of Tool maker’s microscope and its application. 29-31

5 Angle and taper measurement by Bevel protractor Sine bar. 32-36

6 Use of straight edge and spirit level in finding the flatness of surface plate.

37-39

7 Calibration of transducer or thermocouple for temperature measurement. 40-42

8 Study and calibration of photo and magnetic speed pickups for the measurement of speed.

43-45

9 Study and calibration of a rotometer for flow measurement. 46-48

10 Study and calibration of McLeod gauge for low pressure. 49-50

11 Study and Calibration of Vibration analyzer. 51-52

12 Study and calibration of capacitive transducer for angular measurement. 53-54

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EXPERIMENT – 1

MEASUREMENT OF BORES BY INTERNAL MICROMETERS AND DIAL BORE INDICATORS

AIM:

To determine inside diameter and bore diameter is a given work piece specimen. APPARATUS:

Inside micro meter, work piece with different diameters, Bore gauge set

MICRO METER:-

It is one of the most common and most popular form of measuring instrument for

precious measurement with 0.001mm accuracy are also available.

PRINCIPLE:-

Micro meter works on the principle of screw and nut. When screw is turned through

nut one revolutions it advances by one pitch distance i.e., one revolution of screw

corresponds to a linear moment of a distance equal to the pitch of the thread

L.C= Pitch of the spindle/ No of divisions on the spindleL.C= Pitch of the spindle/ No of divisions on the spindleL.C= Pitch of the spindle/ No of divisions on the spindleL.C= Pitch of the spindle/ No of divisions on the spindle

PROCEDURE:-

1. Select the micro meter with a desired range depending upon the size of the work

piece to be measured.

2. The next step is to check it for zero error. In case of 0.25mm micrometer, the zero

error is checked by contracting the faces of fixed anvil and the spindle.

3. The barrel has graduation, in travels of 1mm above the reference line

4. For measuring the dimension, hold work b/w faces of the anvil the spindle by

rotating then touches the work piece

5. Take the thimble reading with coincides with the reference line on the sleeve.

Total reading = MSR + (PSR X LC) mmTotal reading = MSR + (PSR X LC) mmTotal reading = MSR + (PSR X LC) mmTotal reading = MSR + (PSR X LC) mm

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. CD Left jaw (2) Right jaw (3) Contact point (4) Clamping knob (5) Sleeve

(6) Thimble (7) Ratchet stop

Sleeve 22.5mm

Thimble 37mm

Reading 22.87mm

PRECAUTIONS:-

1. First clean the micro meter by wiping off dirt, fit, dust grit off it.

2. Clean them with a piece of cloth or paper

3. Set zero readings on instrument before measuring.

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Inner diameter of the spicemen-1

S No Main Scale

Reading

(mm)

VSR

(mm)

VSR X LC TR= MSR + (VSR

X LC) mm

1

2

3

4

5

Inner diameter of the spicemen-2

S No Main Scale

Reading(mm)

VSR(mm) VSR X LC TR= MSR + (VSR

X LC) mm

1

2

3

4

5

THEORY:-

Bore gauge, is generally used to determine the bore diameter of components. Bore

gauge consists of following parts.

1. Dial gauge

2. Vertical column

3. Arrangement of anvil and washer

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4. Movable spindle

B) DIAL BORE INDICATIORTHEORY AND DESCRIPTION:

Dial bore indicator consists of measuring head and guide is attached with

extension rod &collars for specific dimension chosen from the table in the

instrument box, holder is assembled to the measuring head and dial indicator is fixed

inside the holder during tightening. The condition is initially 1 kg-f is applied to the

dial indicator for getting exact reading.

PRINCIPLE: Dial bore indicator is works on comparator principle.

PROCEDURE:

1) Once approximate bore is finding out by using inside micro meter.

2) Chose the same little more size extension rod & collar if necessary select and fit.

3) Keep the dial bore indicator into the specimen bore.

4) Repeat same procedure to get the bore diameter at different positions of specimen

Least count = 0.01mmLeast count = 0.01mmLeast count = 0.01mmLeast count = 0.01mm

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SAMPLE CALCULATIONS:-

Least count (LC) =0.01mm

Total Reading= MSR+ (TSRX0.01)

CALCULATION TOTAL READING:-

Bore diameter = MSR+ (TSRX0.01)

Inner Diameter of the specimen-1:

S No Dial bore gauge range (mm)

(MSR)

Deflection

(TSR)

TR= dial bore gauge reading+

Deflection X L.C (mm)

1

2

3

4

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Inner Diameter of the specimen-2:

S No Zero

error

Basic size

of gauge

resulted

Dial indicator

reading Original diameters

1

2

3

4

5

RESULT:-

The experiment is used to find the inner diameter/bore diameter of the hollow

specimen of given specimen

The inner diameter of the given specimen is ---------------- mm

The bore diameter of the given specimen is ……………….mm

USE OF GEAR TEETH, VERNIER CALIPERS AND CHECKING

THE CHORDAL ADDENDUM AND CHORDAL HEIGHT OF

AIM: To measure the tooth thickness of a given spur g

INSTRUMENTS REQUIRED

THEORY:

The tooth thickness is defined

opposite faces of the same tooth. Most of the time a gear vernier is used to determine

the tooth thickness. As the tooth thickness varies from top to bottom, any instrument

for measuring on a single tooth. Gear tooth micro meter is used to measure the

thickness of gear tooth at pitch line. It is similar to simple micro meter but gear tooth

micro meter having flanks at the end of anvil and spindle. The flanks of the micro

meter. Gives the thickness

PRINCIPLE:-

Gear tooth micro meter works on the principle of screw and when screw is turned

throughput for one revolution it advances by one pitch distance i.e., one revolution of

screw corresponds to a linear moment of a

Least Count (LC) = Pitch of the spindle screw/ No of divisions of the spindle (mm)

EXPERIMENT – 2



SPUR GEAR

tooth thickness of a given spur gear

INSTRUMENTS REQUIRED: Gear vernier, Vernier caliper, spur gear

defined as the length of the arc of the pitch circle

faces of the same tooth. Most of the time a gear vernier is used to determine


gle tooth. Gear tooth micro meter is used to measure the



of gear tooth at pitch line.



screw corresponds to a linear moment of a distance equal to the pitch of thread.


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circle between

faces of the same tooth. Most of the time a gear vernier is used to determine


gle tooth. Gear tooth micro meter is used to measure the





distance equal to the pitch of thread.


Terminology for Spur Gears:

Pitch surface: The surface of the imaginary rolling cylinder (cone, etc.) that the

toothed gear may be considered to replace.

• Pitch circle: A right section of the pitch

• Addendum circle:

• Root (or dedendum) circle

teeth, in a right section of the

• Addendum: The radial distance between the pitch circle and the addendum

• Clearance: The difference

addendum of the mating

• Face of a tooth: That part of the tooth surface lying

• Flank of a tooth: The part of the tooth surface lying inside the pitch

• Circular thickness

tooth measured on the pitch circle. It is the length of an arc and not the

of a straight line.

• Tooth space: The distance between adjacent teeth measured on the pitch

• Backlash: The difference between the circle thickness of one gear and the

tooth space of the mating

• Circular pitch p: The width of a tooth and

• Diametral pitch P

diameter. A toothed

pitch, therefore, equals the pitch circumference divided by the number of

teeth. The diametral pitch

the pitch diameter. That

and

Terminology for Spur Gears:

: The surface of the imaginary rolling cylinder (cone, etc.) that the

considered to replace.

: A right section of the pitch surface.

A circle bounding the ends of the teeth, in a right

Root (or dedendum) circle: The circle bounding the spaces between the

section of the gear.

: The radial distance between the pitch circle and the addendum

difference between the dedendum of one gear

the mating gear.

: That part of the tooth surface lying outside the pitch

: The part of the tooth surface lying inside the pitch

Circular thickness (also called the tooth thickness): The thickness of the

tooth measured on the pitch circle. It is the length of an arc and not the

: The distance between adjacent teeth measured on the pitch

: The difference between the circle thickness of one gear and the

tooth space of the mating gear.

p: The width of a tooth and a space, measured on the pitch

Diametral pitch P: The number of teeth of a gear per inch of its pitch

diameter. A toothed gear must have an integral number of teeth. The

equals the pitch circumference divided by the number of

diametral pitch is, by definition, the number of teeth divided by

. That is,

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: The surface of the imaginary rolling cylinder (cone, etc.) that the

right section of the gear.

: The circle bounding the spaces between the

: The radial distance between the pitch circle and the addendum circle.

gear and the

outside the pitch surface.

: The part of the tooth surface lying inside the pitch surface.

): The thickness of the

tooth measured on the pitch circle. It is the length of an arc and not the length

: The distance between adjacent teeth measured on the pitch circle.

: The difference between the circle thickness of one gear and the

a space, measured on the pitch circle.

: The number of teeth of a gear per inch of its pitch

The circular

equals the pitch circumference divided by the number of

is, by definition, the number of teeth divided by

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Hence

p = circular pitch

P = diametral pitch

N = number of teeth

D = pitch diameter

That is, the product of the diametral pitch and the circular pitch .

• Module m: Pitch diameter divided by number of teeth. The pitch diameter is

usually specified in inches or millimeters; in the former case the module is

the inverse of diametral pitch.

• Fillet: The small radius that connects the profile of a tooth to the root circle.

• Pinion: The smallest of any pair of mating gears. The largest of the pair is

called simply the gear.

• Velocity ratio: The ratio of the number of revolutions of the driving (or

input) gear to the number of revolutions of the driven (or output) gear, in a

unit of time.

• Pitch point: The point of tangency of the pitch circles of a pair of mating gears.

• Common tangent: The line tangent to the pitch circle at the pitch point.

• Line of action: A line normal to a pair of mating tooth profiles at their point of contact.

• Path of contact: The path traced by the contact point of a pair of tooth profiles.

• Pressure angle: The angle between the common normal at the point of tooth

contact and the common tangent to the pitch circles. It is also the angle

between the line of action and the common tangent.

• Base circle: An imaginary circle used in involute gearing to generate the involutes that

form the tooth profiles

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PROCEDURE:

1. The least count is to be determined.

2. The work piece is placed between the jaws of vernier calipers correctly.

3. The reading of the main scale which is just behind the first scale division is noted as main scale reading.

4. The division on vernier scale which coincide with the line on main scale is noted down as vernier coincidence.

5. Similarly for four teeth, two teeth, width and all the parameters can be calculated by using the given formula.

6. The vertical gear tooth vernier is made of point the calculate the depth value.

7. Now the gear tooth, i.e. kept in between in the two jaws of the gear tooth vernier.

8. Observe the main scale reading and vernier scale coincidence of the horizontal scale. 9. Repeat the observation of different position of the same tooth and calculate the average.

CALCULATIONS: Least count of vernier calipers = 1- /VSR Diametrical Pitch = (T+2)/Outside diameter (D) Bore Pitch (Pb) = (b-a)/y Where a= Distance between two teeth

b = Distance between four teeth y=2

Base circle circumference = TXPb

Base circle diameter (Db) = TXPb /π

Base pitch circle diameter (DP) = T/Db

Pressure angle (ϴ) = cos-1(DP/D)

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Width of tooth of pitch circle (w) = T/ DP ((sin(90/T))

Chordal addendum (h) = T/2 DP(1-cos(90/T))+1/ DP

Width of teeth using gear tooth vernier (wg) =

Least count of main scale of gear tooth vernier = Error of gear tooth vernier = ((W vernier – W gear vernier )/W vernier)

Least count: Horizontal scale=0.02mm

Vertical scale =0.02mm

S.No Outside diameter (mm)

Distance over 4 teeth (b)

Distance over 4 teeth (b)

By using gear tooth vernier calipers

By using vernier calipers

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S.No Trial Chordal Thickness

In inches In mm



MODEL CALCULATION:

Module = outer dia/ (Z+2)

Depth = (Zm/2) (1+2/Z-COS (90/Z))

Width = Zm x sin (90/Z)

Deviation =theoretical value-actual value

RESULT:

Thus the thickness of the gear tooth of the given spur gear is calculated using gear tooth vernier.

Depth of the gear tooth = …………mm

Width of the gear tooth = …………mm

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EXPERIMENT – 3(a)

MACHINE TOOL “ALIGNMENT TEST ON THE LATHE”

Aim:-

1. Test for level of installation:

(a) In a longitudinal b) In transverse direction

Measuring instruments: Spirit level, gauge block to suit the guide ways of the lathe bed.

Theory:-

The following are the alignment tests on lathe.

Levelling of machine:-

It is essential that a machine tool should be installed truly horizontal and vertical plane

and this accuracy must be maintained. The level of machine base in longitudinal and

transverse direction is tested by spirit level or precision level. The spirit level is

placed at to measure the level.

True running of main spindle:-

The true mandrel is placed in the main spindle and test is conducted on the surface of

material if dial gauge shows any deviation in the reading then it is said that the main

spindle is running in the proper way.

Parallelism of main spindle to saddle movement:-

If the axis of the spindle is not parallel to the saddle movement then it is not possible

to get required dimension of work piece while doing the operation on lathe. The

spindle is moved and the deviation in the reading of dial gauge are noted.

Parallelism of Tailstock guide ways to saddle movement:-

To check the parallelism of guide ways with the saddle movement in the both

vertical and horizontal directions. The dial indicator is held on the spindle and block

is moved simultaneously any deviation in reading of dial gauge is noted if no

deviation in the reading then tail stock guide ways is parallel to saddle movement

otherwise it is not parallel to saddle movement.

Parallelism of tail stock guide ways to carriage movement:-

To check the parallelism of guide ways with the carriage in both vertical and

horizontal objections. A block is placed on the guide ways of tail stock. The dial

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indicator is held on the carriage and block is moved simultaneously any deviation in

reading of dial gauge is noted

Parallelism of main spindle to carriage movement:-

To check the parallelism of main spindle to carriage in both vertical and horizontal.

The deviation is observed the spindle is not parallel to the carriage.

True Running of head stock centre:-

The test mandrel is placed in the head stock and test is conducted on the surface of

carriage. The dial gauge shows any deviations in the reading then the head stock is not

running in proper.

Procedure: - The gauge block with the spirit level is placed on the bed ways on the

front position, back position and in the cross wise direction. The position of the

bubble in the spirit level is checked and the readings are taken.

1. Permissible error: Front guide ways. 0.02 mm/meter convex only. Rear guide

ways, 0.01 to0.02 convexity. Bed level in cross-wise direction ±0.02/meters.

Straightness of slide ways(for machines more than 3 mm turning length only,

measurement taken by measuring tight wire and microscope or long straight edge).

Tailstock guide ways parallel with movement of carriage 0.02 mm/m. No twist is

permitted.

The error in level may be corrected by setting wedges at suitable points under the

support feel or pads of the machine.

2. Straightness of saddle in horizontal plane:-

Measuring instruments: Cylindrical test mandrel (600mm long), dial indicator.

Procedure: - The mandrel is held between centres. The dial indicator is mounted on

the saddle. The spindle of the dial indicator is allowed to touch the mandrel. The

saddle is then moved longitudinally along the length of the mandrel. Readings are

taken at different places.

Permissible error: 0.02 mm over length of mandrel.

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3. Alignment of both the centres in the vertical plane:

Measuring instruments: Cylindrical mandrel 600 mm long, dial gauge.

Procedure: The test mandrel is held between centres. The dial indicator is mounted

on the saddle in vertical plane as shown in figure. Then the saddle along with the dial

gauge is travelled longitudinally along the bed ways, over the entire length of the

mandrel and the readings are taken at different places.

Permissible error: 0.02 mm over 600 mm length of mandrel (Tail stock centre is to

lie higher only).

4. True running of taper socket in main spindle

Instruments required: Test mandrel with taper shank and 300 mm long cylindrical

measuring part, dial gauge.

Procedure: The test mandrel is held with its taper shank in a head stock spindle

socket. The dial gauge is mounted on the saddle. The dial gauge spindle is made to

touch with the mandrel. The saddle is then travelled longitudinally along the bed

ways and readings are taken at the points A and B as shown in figure.

Permissible error: Position A 0.01 mm, position B 0.02 mm.

5. Parallelism of main spindle to movement:

(a) In a vertical plane (b) In a horizontal plane

Measuring instruments: Test mandrel with taper shank and 300 mm long

cylindrical measuring part, dial gauge.

Procedure: The dial gauge is mounted on the saddle. The dial gauge spindle is made

to touch the mandrel and the saddle is moved to and fro. It is checked in vertical as

well as in horizontal plane.

Permissible error: (a) 0.02/300 mm mandrel rising towards free end only.

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(b) 0.02/300 mm mandrel inclined at free end towards tool pressure only.

6. Movement of upper slide parallel with main spindle in vertical plane:

Measuring instruments: Test mandrel with taper shank and 300 mm long

cylindrical measuring part, dial gauge.

Procedure: The test mandrel is fitted into the spindle and a dial gauge clamped to

the upper slide. The slide is transverse along with the dial gauge plunger on the top

of the stationary mandrel.

Permissible error: 0.02 mm over the total movement of the slide.

7. True running of locating cylinder of main spindle:

Measuring instrument: Dial gauge.

Procedure: The dial gauge is mounted on the bed, touching at a point on main

spindle. The main spindle is rotated by hand and readings of dial gauge are taken.

Permissible error: 0.01 mm.

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8. True running of head stock center:

Measuring instruments: Dial gauge.

Procedure: The live center is held in the tail stock spindle and it is rotated. Its

trueness is checked by means of a dial gauge.

Permissible error: 0.01 mm.

9.Parallelism of tailstock sleeve to saddle movement:

Measuring instruments: Dial indicator

Procedure: Tailstock sleeve is fed towards. The dial gauge is mounted on the saddle. Its

spindle is touched to the sleeve at one end and the saddle is moved to and fro, it is checked in

H.P. and V.P. also.

Permissible error: (a) 0.0 1/100 mm (Tailstock sleeve inclined towards tool pressure only).

(b) 0.0 1/100 mm (Tailstock sleeve rising towards free end only).

PRECAUTIONS:

i) The mandrel must be so proportioned that its overhang does not produce

appreciable sag, else the sag must be calculated and accounted for.

ii) The indicator set up must be rigid, otherwise variations in readings as recorded by

point may be solely due to deflection of the indicator.

REVIEW QUESTIONS

a) What is the necessity of conducting various alignment tests on lathe?

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b) What are the various alignment tests to be conducted on the lathe?

c) What is straightness?

d) What is flatness?

e) What is square ness?

f) What is parallelism?

g) What do you mean by axial slip of main spindle?

h) It is necessary to conduct alignment tests on other machine tools? If so why? Not, why not?

EXPERIMENT – 3(b)

MACHINE TOOL “ALIGNMENT TEST ON MILLING MACHINE”

Aim:-

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To perform the alignment test on milling.

Apparatus:-

Spirit level, gauge blocks, dial gauge

Theory:-

Following are the tests on milling machine

Test for levelling of milling machine:-

It is essential that a machine tool should be installed truly horizontal and vertical plane

and this accuracy must be maintained. If milling base is not installed truly horizontal

then bed will undergo a deflection and produce a simple bend.

True Running of spindle:-

A mandrel placed in the spindle and test is conducted on the surface of mandrel. A

dial gauge is fixed on the machine table and feeler of the dial gauge is made to touch

the lower surface of it clearance is noted then it is said that the table is not flat

otherwise it is flat.

True Running of spindle:-

For this test the mandrel is placed in the spindle and dial indicator is fixed on the

table. The feeler of dial gauge is made to touch the surface of manderal.

Parallelism of spindle Axis with its vertical moment:-

For this test the manderal is placed in the spindle and dial indicator is fixed on the

table. The feeler of dial gauge is made to touch the surface of mandrel also moved up

and down, the mandrel also moved up and down observe any direction in the reading

of dial gauge is noted then that is said that it is not running in proper way mandrel.

Axis slip of main spindle is developed due to the error in bearing support for this test

feeler of the dial gauge is placed on the face of main spindle and the dial gauge.

Parallelism (or) Table Surface with longitudinal surface:-

A machine is placed in the spindle and test is conducted on the surface of mandrel. If

any degration is noted then it is noted then it is said that spindle is not parallel to the

table.

Parallelism of Table Surface with main spindle:-

A mandrel is placed in the spindle and test is conducted on the surface of mandrel. A

dial gauge is fixed on the table and feeler is touched to the spindle. If any deviation

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takes place the spindle is not machine to the table.

Parallelism of Table Surface with Arbor:-

Arbor is placed in the spindle and test is conducted on the surface of order. If any

degration is noted than it is said that arbor is not parallel to the table.

Procedure:

(1) Flatness of work table

(a) In longitudinal direction.

(b) In transverse direction.

Measuring instruments: -

Spirit level.

Procedure: - A spirit level is placed directly on the table at points about 25 to 30 cm

apart, at A, B, C for longitudinal tests and D, E and F for the transverse test. The

readings are noted.

Permissible error:

Direction A-B-C, ±

0.04 mm Direction

D-E-F, ± 0.04 mm

(2) Parallelism of the work table surface to the main spindle

Measuring instruments: Dial indicator, test mandrel 300 mm long, spirit level.

Procedure: The table is adjusted in the horizontal plane by spirit level and is then

set in its mean position longitudinally. The mandrel is fixed in the spindle taper. The

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dial gauge is set on the machine table, and the feeder adjusted to touch the lower

surface of the mandrel. The dial gauge readings at (A) and (B) are observed, the stand

of the dial gauge being moved while the machine table remains stationary’.

Permissible error: 0.02/3 00 mm.

(3) Parallelism of the work table surface to the main spindle

Measuring instruments: Dial indicator, test mandrel 300 mm long, spirit level.

Procedure: The table is adjusted in the horizontal plane by spirit level and is then

set in its mean position longitudinally. The mandrel is fixed in the spindle taper. The

dial gauge is set on the machine table, and the feeder adjusted to touch the lower

surface of the mandrel. The dial gauge readings at (A) and (B) are observed, the stand

of the dial gauge being moved while the machine table remains stationary’.

Permissible error: 0.02/3 00 mm

(4)Parallelism of the clamping surface of the work table in its longitudinal

motion: Instruments: Dial gauge, straight edge.

Procedure: A dial gauge is fixed to the spindle. The dial gauge spindle is adjusted to

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touch the table surface. The table is then moved in longitudinal direction and

readings are noted. If the table surface is uneven it is necessary to place a straight

edge on its surface and the dial gauge feeder is made to rest on the top surface of the

straight edge.

Permissible error: 0.02 up to 500 mm length of transverse, 0.03 up to 1000 mm

and 0.04 above1000 mm length of transverse.

(5)Parallelism of the cross (transverse) movement of the worktable to the main spindle:

( a) In vertical plane

(b) In horizontal plane

Instruments: Dial gauge, test mandrel with taper shank.

Procedure: The work table is set in its mean position. The mandrel is held in the

spindle. A dial gauge fixed to the table is adjusted so that its spindle touches the

surface of the mandrel. The table is moved cross-wise and the error is measured in

the vertical plane and also in the horizontal plane.

Permissible error: 0.02 for the overall transverse movement of the work table.

(6)True running of internal taper of the spindle:

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Instruments: 300 mm long test mandrel, dial gauge.

Procedure: The test mandrel with its taper shank is held in the main spindle. Dial

gauge is kept scanning the periphery of the mandrel. Spindle is rotated and dial gauge

readings are noted at different points say A and B as shown.

Permissible error: Position A: 0.01 mm, Position B: 0.02 mm.

(7)Square nests of the centre T-slot of worktable with main

spindle Instruments: Dial gauge, special bracket.

Procedure: To check the perpendicularity of the locating slot and the axis of the main

spindle. The table should be arranged in the middle position of its longitudinal

movement, and a bracket with a tenon at least 150 mm long inserted in the locating

slot as shown in figure. A dial gauge should be fixed in the taper, the feeder being

adjusted to touch the vertical face of the bracket.

Observe the reading on the dial gauge when the bracket is near one end of the table,

the swing over the dial gauge and move the bracket so that the corresponding

readings can be taken near the other end of the table.

Permissible error: 0.025 mm in 300 mm.

(8) Parallelism of the T-slot with the longitudinal movement of the

table: Instruments: Dial gauge, special bracket.

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Procedure: The general parallelism of the T-slot with the longitudinal movement of

the table is checked by using 150 mm long braked having a tenon which enters the

slot, the dial gauge is fixed to the spindle taper and adjusted so that its feeder touches

the upper surface of the bracket. The table is then moved longitudinally while the

bracket is held stationary by the hand of the operator and dial gauge deviations from

parallelism are note down.

Permissible error: 0.0 125 mm in 300 mm.

(9)Parallelism between the main spindle and guiding surface of the overhanging arm

Instruments: Dial gauge, mandrel.

Procedure: The overhanging arm is clamped in its extreme extended position.

The dial gauge is fixed to the arbor support. The feeder of the dial gauge is

adjusted to touch the top or ride of the test mandrel. The arbor can then be

moved along the overhanging arm and the deviations from parallelism observed

on the dial gauge.

PRECAUTIONS:

i) All moving parts of the machine must be locked while reading the dial gauge,

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ii) If the table surface is uneven, straight edges must be used.

REVIEW QUESTIONS:

i) Distinguish between geometric tests and practical tests.

ii) How will you measure the flatness of the table surface?

iii) What are the various alignment tests conducted on vertical milling machine?

iv) What are the various measuring instruments used in alignment test of a

milling machine

v) What are the dimensions of a test piece used in practical test?

EXPERIMENT – 4

TOOL MAKER’S MICROSCOPE AND ITS APPLICATION

Aim:-

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Study of Tool Maker’s Microscope.

Objectives:

• After performing this experiment, you should be able to • Appreciate the importance of precision measurement, • Know how precise measurements can be taken with this instrument, • Explain the field of application/working of this instrument, and • Understand the principle of working of tool room microscope.

Introduction:

Engineering microscopes designed to satisfy various measuring needs of toolmakers

are known as toolmaker’s microscopes. A plain toolmaker’s microscope is primarily

intended for a particular application. On the other hand, universal toolmaker’s

microscope is adaptable to an uncommonly wide range of measuring tasks. A

toolmaker’s microscope is designed for measurements of parts of complex forms,

e.g. profile of external threads, tools, templates and gauges. It can also be used for

measuring centre‐to‐centre distance of holes in any planes, as well as the co‐ordinate

of the outline of a complex template gauges.

Apparatus:-

BRIEF DESCRIPTION OF INSTRUMENT: FIG: TOOL MAKERS MICROSCOPE

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It consists of optical head, which can be adjusted vertically along the ways of the

vertical column and can be clamped in any position. The working table is secured on

a heavy hollow base. The table has a compound slide to give longitudinal and lateral

movements actuated by accurate micrometer screws having thimble scales and

vernier. At the back of the base is a light source, which provides a horizontal beam of

light reflected upwards by 90otowards the table. This beam of light passes through a

transparent glass plate on which flat parts to be checked are placed. A shadow image

of the outline of the contour passes the objective of the optical head and is projected

by a combination of three prisms to a ground glass screen. Observations are made

through the eyepiece of the optical head. Figure gives the views of a tool room

microscope. Cross lines are engraved on the glass screen, which can be rotated

through 360o, and these lines make the measurements. The angle of rotation of

screen can be read on the optical head. The eyepiece field of view contains an

illuminated circular scale with a division value of one minute. Adjusting optical head

tube performs focusing.

Theory:-

The tool maker microscope is designed for measurement of components of difficult forms. Ex: - profile of external threads, tools, gauge. It can be used for measuring center to

center distance of holes in any plane it consists of optical head which can be adjusted vertically along

inspection the table can be moved in longitudinal direction and lateral direction by micro meter screws,

which are having barrel and thimble at back of base light is arranged which provides on the optical

head. The image of component passes through optical head and observations. The reading of

longitudinal micro meter is noted. The difference gives the pitch of the thread.

PROCEDURE:

1. Switch on the main.

2. Switch on the micros scope lights.

3. Select the capacity of the lens for precision operation.

4. Place the object on the class table to get the clear image rotate the wheel provided at

the light side.

5. After getting the clear image, locate the crosswire at the initial point on the image.

Now note down the micro meter reading.

6. Move the cross wire from initial point to the finial point on the image, which is to

be measured. Note down the micro meter reading, this operation is done by using

micrometer.

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7. Now the different but when the initial and the finial reading i.e. distance travelled

gives the size of the object.

Precautions:-

1) Obtain clean picture of cross line and the cross thread seen through the eyepiece.

2) For angular measurements lines must remain parallel to flank edge to the tooth.

S.No Main scale reading (MSR)

Pitch scale reading (PSR)

Total reading (TR)

RESULT:

Thus the all dimensions of the given particular screw were measured by using

toolmaker’s microscope.

EXPERIMENT – 5

ANGLE AND TAPER MEASUREMENTS BY BEVEL PROTRACTOR, SINE BARS

Aim: - To measure the taper angle of the given specimen using bevel protractor and sine bar

method.

APPARATUS REQUIRED:

1. Sine bar 2. Micrometer 3. Slip gauge set 4. Surface plate 5. Dial gauge withstand

6. Vernier caliper 7.Combination Sets 8. Bevel Protector

Theory:

BEVEL PROTECTOR

A universal bevel protractor is used to measure angles between two planes. This

consists of stem, which is rigidly attached to main scale and a blade, which is attached to the

Vernier scale and can be rotated to read angles. To improve the accessibility, the blade can

also slide.

The least count is calculated by knowing the value of the smallest division on the main

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scale and number of division on the Vernier scale. It should be noted that the divisions on the

main scale is in degrees and that the fractional divisions of degrees are minutes (i.e. with 60

minutes/degree, denoted). To measure angle between two planes, rest the stem on one of the

planes (reference plane). Rotate the blade such that blade is flush with second plane.

Readings are taken after ensuring that the stem and blade are in flush with the two

planes. Lock the protractor at this point and note sown the readings.

OBSERVATIONS:

S.No MSR VSR VSRXLC TR=MSR+(VSR+LC)

PRECAUTIONS:

1. The sine bar should not be used for angle greater than 600 because any

possible error in construction is accentuated at this limit.

2. A compound angle should not be formed by miss-aligning of work piece with the

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sine bar. This can be avoided by attaching the sine bar and work against an angle

plate.

3. As far as possible longer sine bar should be used since using longer sine bars

reduces many errors.

RESULT:

The angle of the given specimen measured with the Bevel Protractor is…………………..

SINE BAR

The sine principle uses the ratio of the length of two sides of a right triangle in deriving

a given angle. It may be noted that devices operating on sine principal are capable of self-

generation. The measurement is usually limited to 45 degree from loss of accuracy point of

view. The accuracy with which the sine principle can be put to use is dependent in practice,

on some from linear measurement. The sine bar itself is not complete measuring instrument.

Another datum such as surface plate is needed, as well as other auxiliary instrument, notably

slip gauge, and indicating device to make measurements.

A sine bar is a tool used to measure angles in metalworking.

A sine bar is a tool used to measure angles in metalworking.

FIG: SINE BAR

It consists of a hardened, precision ground body with two precision ground cylinders fixed

at each end. The distance between the centers of the cylinders is precisely controlled, and the

top of the bar is parallel to a line through the centers of the two rollers. The dimension

between the two rollers is chosen to be a whole number (for ease of later calculations) and

forms the hypotenuse of a triangle when in use. The image shows a 10 inch and a 100 mm

sine bar.

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When a sine bar is placed on a level surface the top edge will be parallel to that surface. If

one roller is raised by a known distance then the top edge of the bar will be tilted by the same

amount forming an angle that may be calculated by the application of the sine rule.

• The hypotenuse is a constant dimension — (100 mm or 10 inches in the

examples shown).

• The height is obtained from the dimension between the bottom of one

roller and the table's surface.

The angle is calculated by using the sine rule.

FORMULA:

Sin Ø = h / LSin Ø = h / LSin Ø = h / LSin Ø = h / L

Where,

H - Height of the slip gauge

L - Distance between the

centres Ø - Inclined angle

of the specimen

PROCEDURE:

• The given component is placed on the surface plate.

• One roller of sine bar is placed on surface plate and bottom surface of sine bar is seated on

the taper surface of the component.

• The combination of slip gauges is inserted between the second rollers of sine bar and the

surface plate.

• The angle of the component is then calculated by the formula given above.

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S.No Length of the sine

bar (L) mm

Height

(h)mm

Taper angle ()

CALCULATION:

Sin Ø = h / L

Precaution in Sine Bars:-

(a) A Compound angle should not be formed by miss dignity of w/p with the sine

bar. This can be avoided by attaching the sine brand work against an angle plate.

(b) Accuracy of sine bar should be ensured.

(c) As far as possible longer sine bar should be used since4 many errors are reduced

by using longer sine bar.

Precautions:-

1. Angle of instrument must coincide with the angular scale

2. Gripped the instrument to the measuring face exactly

Result:-

Thus the taper angle of the given specimen is measured using sine bar. The external taper

angle is……………………………………..

VIVA – QUESTIONS

1. What is the use of angle plates?

2. Name some angle measuring devices?

3. What is the least count of mechanical Bevel Protractor?

4. What is the least count of optical Bevel Protractor?

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5. What is a sine bar?

6. What are the limitations of Sine bar?

7. What is the difference between the sine bar and sine center?

8. What is the use of V-block?

9. What is the purpose of adjusting nuts in a micro meter?

10. What is the least count of dial indicator?

11. How do you specify sine bar?

EXPERIMENT – 6

USE OF SPIRIT LEVEL IN FINDING THE FLATNESS OF SURFACE

PLATE

Aim:-

To check the flatness of given surface plate

Apparatus:-

Spirit level, surface plate

Theory:-

Generally spirit level is used for levelling the machinery and other instruments. But spirit

levels are also used to measure the angles. It is also called precision level. It consists of glass

tube and of the tube. If the tube is fitted through a small angle if R- radius of tube L distance

of bubble moved when spirit level is fitted to same angle

The simplest form of flatness testing is possible by comparing the surface with an

accurate surface. Spirit level is used in special cases and called Clinometers, precision micro-

optic clinometers utilizes bubble unit with a prismatic coincidence reader which presents both

ends of the bubble an adjacent images in a spirit field. Leveling helps in the coincidence of

the 2 images, making it very easy to sec when the bubble is exactly centered without

reference to any graduations. The special features to precision micro-optic clinometers arc

direct reading over range 0-360°, optically reading system, main coarse setting, slow motion

screw to fine setting. The least count of precision spirit level is 0.01 mm.

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The spirit of level consists of a sealed glass tube mounted on a base. The inside surface

of the tube is ground to a convex barrel shape having large radius. The precision of the level

depends on the accuracy of this radius of the tube. A scale is engraved on the top of the glass

tube. The tube is nearly filled with either ether or alcohol, except a small air or vapour in the

form of a bubble.

The bubble always tries to remain at the highest point of the tube. If the base of the

spirit level is horizontal, the centre point is the highest point of the tube. So, that when the

level is placed on a horizontal surface, the bubble rests at the centre of the scale. If the base of

the level is fitted through a small angle, the bubble will more relative to the tube a distance

along its radius corresponding to the angle.

Fig: surface plate Fig: Spirit level

The figure shows two positions of the base of the level (OA1 and OA2) and

corresponding positions of the bubble (Bl, B2). When the base OA1 is horizontal, the bubble

occupies positionB1. Let ‘ϴ‘be the small angle through which the base is fitted. The bubble

now occupies the position B2.Let L be the distance travelled by bubble along the tube and ‘h’

the difference in heights between the ends of the base. Then L= R and h =. L

Therefore = =

Therefore =

Where R = radius of curvature of

the tube L = length of base

Finally =

Procedure:

1 Place the spirit level on the surface plate for which we have to find out

the flatness 2 Find the base length of the spirit level

3 Note the radius of curvature of the spirit

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level tube 4 Find the tilt in the bubble

5 Finally find out the difference in heights between the ends of the base.

Flatness of the specimen:

S.NO Distance travelled by the bubble

Difference in height between

ends

Angle ‘ϴ’

1

2

3

4

5

Precautions:

1 .Clean the surface plate and ensure there is no dust particles

2. Take the bubble reading without any parallax error.

Result:-The experiment has been conducted on spirit level to check the flatness of

given surface plate. The given surface plate is flat/not flat---------------------

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EXPERIMENT – 7

TEMPERATURE MEASUREMENT BY THERMOCOUPLE AND

THERMISTER

Aim: To study temperature transducers, Thermocouple, Thermistor by using digital

temperature indicator.

Apparatus required: Temperature transducers, Digital temperature indicator, Thermometer,

Electric sterilizer.

Procedure:

1. Select the Thermocouple/RTD/Thermister by selector switch. 2. Connect the Thermocouple/RTD/Thermister to sensor socket provided at front panel. 3. Set the min pot to read the ambient temperature in display. 4. Insert Thermocouple/RTD/Thermister in the hot bath. 5. 3 digit LED display shows the temperature obtaining at the hot bath directly in degrees

Celsius. 6. If necessary adjust the max pot for the maximum level of temperature calibration. 7. Recorder red and green terminals for the anal output. 8. Fuse holder provider to protect the circuit from the over load (500 mA).

Thermocouple:

It is the simplest and commonly used methods of measuring process temperature. The

operation of Thermocouple is based on seebeck effect. See back discovered that when heat is

supplied to the junction of two dissimilar metals, an emf is generated which can be measured at

the other junction. The two dissimilar metals form an electric circuit and current flows as a

result of the generated emf.

Construction of Thermocouple

A pair of two dissimilar metals that are in physical contact with each other

Thermocouple. These metals may be twisted, screwed, pinned, clamped or welded together.

The most commonly used method for fabricating is to weld metals together. Thermocouple

do not use bare conductors except in applications where atmosphere conditi

use. These conditions obtained when temperature to be measured are low and atmosphere is

non corrosive. Industrial Thermocouples employ protective sheathing surrounding the

junction and a portion of the extension leads. The lead and junct

from the sheath using various potting

insulations is used depends upon the process being monitored.

Type of the sensor

Material use

Thermistor:

Thermister is a contraction of term “thermal resistors”. Thermister are generally

composed of semi conductor materials. Although positive temp co efficient of units

which exhibits an increase in the value of resistance can be as large as several percent

per degree Celsius. This allows the Thermister circuits to detect very small changes.

This temperature which could not be observed with an RTD or a thermocouple, in

some cases the resistance of Thermister at room temperature may decrease as much as

5% for each that is raise in temperature. This high sensitivity to temperature change

makes Thermisters extremely useful for precision temperature measurements control

and compensation.

Thermister are widely used in applications which involved measurements in the

range of -160 C to 15

Construction of Thermocouple:

A pair of two dissimilar metals that are in physical contact with each other



do not use bare conductors except in applications where atmosphere conditi



junction and a portion of the extension leads. The lead and junction are internally insulated

from the sheath using various potting compound, ceramics beads or oxides .The type of

insulations is used depends upon the process being monitored.

Type of the sensor : “J” type

: chromium Alumel




r degree Celsius. This allows the Thermister circuits to detect very small changes.



ch that is raise in temperature. This high sensitivity to temperature change


and compensation.


C to 150 C .The resistances of Thermister ranges from 0.5

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A pair of two dissimilar metals that are in physical contact with each other form a



do not use bare conductors except in applications where atmosphere conditions permits their



ion are internally insulated

compound, ceramics beads or oxides .The type of




r degree Celsius. This allows the Thermister circuits to detect very small changes.



ch that is raise in temperature. This high sensitivity to temperature change



C .The resistances of Thermister ranges from 0.5 Ω to 0.75 Ω.

Thermister is highly resistive device. The price to be paid off for the high sensitivity

is in terms of linearity. The Thermister exhibits highly non linear characteristic

resistance verse temperature.

Fig : Temperature measuring circuit using thermisterCONTROLS

MIN: 10K single turn potentiometer to set the min level of temperature (i.e., ambient temperature) MAX: 10K single turn potentiometer to adjust the max RTD/ Thermocouple: screw type connecting socket to connect the RTD/ Thermocouple/Thermister sensor.

Tabulation:

S.No. Thermocouple Reading in

J K

1 2 3 4 5 6

Graphs : Thermometer Reading Vs Thermister Reading Model graph:


is in terms of linearity. The Thermister exhibits highly non linear characteristic

resistance verse temperature.

Fig : Temperature measuring circuit using thermister

MIN: 10K single turn potentiometer to set the min level of temperature (i.e., ambient

MAX: 10K single turn potentiometer to adjust the max level of temperature.

RTD/ Thermocouple: screw type connecting socket to connect the RTD/ Thermocouple/Thermister sensor.

Thermocouple Reading in oC RTD Thermister Thermometer

Reading Reading Reading

T In oC In oC In oC

Thermometer Reading Vs Thermister Reading

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is in terms of linearity. The Thermister exhibits highly non linear characteristics of

MIN: 10K single turn potentiometer to set the min level of temperature (i.e., ambient

level of temperature.

Thermometer

Reading

Result: Thus the Temperature of transducer, Thermo couples, Thermistor were calibrated using digital thermometer.

STUDY AND CALIBRATION OF PHOTO AND MAGNETIC SPEED PICKUPS

FOR THE MEASUREMENT OF SPEED

Aim: To measure the speed of the motor by using optical/photo/magnetic proximity

sensors

Apparatus required: Digital speed indicator,

Magnetic sensor Procedure:

1. Connect the main chord to 230V 50Hz AC supply. 2. Connect the sensor socket provided at the back panel optical/proximity sensor. 3. Switch on the instrument and the motor. Then vary the speed o

different steps. 4. Note the readings given in the tabular column.

Digital speed indicator is microprocessor circuit design, accuracy, digital read out. If it is ideal

inspecting and measuring the speed of moving gear spans centrifuges,

equipments. It is non contact sensing devices photo optical and magnetic/ proximity type

sensors. It will take signals from this sensor and these signals will be input to the indicator and

that signal will convert into actual RPM of

RPM directly.

Magnetic pickup ( Proximity) sensor

It is not contacting sensing device, it sensor to the signal from the rotating body and is very

accurate and very reliable and this sensing device is

pick up.

Thus the Temperature of transducer, Thermo couples, Thermistor were calibrated using

EXPERIMENT – 8


FOR THE MEASUREMENT OF SPEED

: To measure the speed of the motor by using optical/photo/magnetic proximity

: Digital speed indicator, Optical or photo sensor, Proximity or

Magnetic sensor

Connect the main chord to 230V 50Hz AC supply.

Connect the sensor socket provided at the back panel optical/proximity sensor.

Switch on the instrument and the motor. Then vary the speed of the motor in

Note the readings given in the tabular column.


inspecting and measuring the speed of moving gear spans centrifuges, pumps, motors and other



that signal will convert into actual RPM of the motor and indicator will indicate the reading in

Magnetic pickup ( Proximity) sensor


accurate and very reliable and this sensing device is non contact type and is equal to magnetic

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Thus the Temperature of transducer, Thermo couples, Thermistor were calibrated using


: To measure the speed of the motor by using optical/photo/magnetic proximity

Optical or photo sensor, Proximity or

Connect the sensor socket provided at the back panel optical/proximity sensor.

f the motor in


pumps, motors and other



the motor and indicator will indicate the reading in


non contact type and is equal to magnetic

Optical/ photo pickup

It is not contacting sensing device, the lever which is fixed to a rotating shaft from a motor. As

the lever rotates with the speed of the shaft, The light passes by the sensor

by lever is received by sensor in turn producing an output pulse representing a logic “1”. These

pulses are sent to a register of counter and finally to an output display to show the speed or

revolutions of the shaft.

CONTROLS: (1) FRONT PANEL

POWER ON : 2 SPDT switch supplies the AC mains into the indicator.

OPTICAL/PROXIMITY: This switch we can select the sensing device of optical/

(2) BACK PANEL

OPTICAL SENSOR : 3 pin sockets are provided to connect t

PROXIMITY : 3 pin sockets are provided to connect the sensor to indicator.

POWER CABLE: 2 pin 2 core cable interconnects the 230 V


the lever rotates with the speed of the shaft, The light passes by the sensor and reflected back



(1) FRONT PANEL

: 2 SPDT switch supplies the AC mains into the indicator.


proximity.

: 3 pin sockets are provided to connect the sensor to indicator.


2 pin 2 core cable interconnects the 230 V -50Hz AC main into the

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and reflected back



: 2 SPDT switch supplies the AC mains into the indicator.


he sensor to indicator.


50Hz AC main into the

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AC main into the instrument.

FUSE : 500 mA fuse is used to protect the instrument from the short circuit.

Tabulation

S.No. Optical/photo sensing Proximity/magnetic sensing device Reading device Reading

1

2 3

4

5 6

Model graph

Result: Thus the speed is calibrated by using photo/optical and magnetic pick up sensor

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EXPERIMENT – 9

STUDY AND CALIBRATION OF A ROTOMETER FOR FLOW

MEASUREMENT

AIM : To calibrate the rotometer by using Rotometer experimental setup

Apparatus Required: Rotometer setup, Stop watch , 2lts capacity collecting jar,

control valve, water circulating system etc., Procedure: 1. Fill the water in storage container

2. Connect the submersible water pump and motor unit to the AC supply 3. Set the regulator for initial flow. 4. Switch on the power supply. 5. Adjust the volume flow rate of water to a certain value by by regulating

valve and collect water in 2lts jug 6. Note down the time consumption for collection of 2lts water by using stop

watch 7. Calculate theoretical discharge for the above measured flow by

60

Using Q = 2 min where t = time consumption for 2 lts

8. Repeat above 5 or 6 times by increasing the flow at each time and note

down the time consumption. 9. Compare the theoretical flow rate with actual flow rate.

10. Plot the graph between theoretical discharge with actual discharge.

Theory :

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The rotometer consists essentially a tapered metering glass tube, inside a float which is located in the Rotameters. The tube is provided with suitable inlet and outlet connecting the float or bob having a specific gravity higher than that of fluid to be metered. In these devices, the falling and rising action of a float in a tapered tube provides a measure of flow rate . Rotameters are known as gravity-type flow meters because they are based on the opposition between the downward force of gravity and the upward force of the flowing fluid. When the flow is constant, the float stays in one position that can be related to the volumetric flow rate. That position is indicated on a graduated scale. Note that to keep the full force of gravity in effect, this dynamic balancing act requires a vertical measuring tube.

The tapered tube's gradually increasing diameter provides a related increase in the annular

area around the float, and is designed in accordance with the basic equation for volumetric

flow rate:

where:

Q = volumetric flow rate, e.g., Lts per minute k = a constant

g = force of gravity h = pressure drop (head) across the float

(OR)

Cd = Coefficient of discharge

Vf = Volume of float

f = Density of float =

2 =

Cd = Coefficient of discharge

Vf = Volume of float

f = Density of float =

2 =

Tabulation:

Sl. No.

1 2 3 4 5

Model graph:

Sl. No. Actual flow Theoretical flow

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Theoritical flow reading

Result: Thus the rotometer is calibrated with theoretical value

EXPERIMENT – 10

STUDY AND CALIBRATION OF MCELOD GAUGE

Aim: Low pressure measurement by McLeod gauge.

Apparatus required: McLeod gauge, vacuum chamber, vacuum pump.

Procedure:

1. Connect the tubes (pipes) from vacuum pump to vacuum chamber and vacuum pump

to McLeod gauge.

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2. Open the outlet wall before starting the vacuum pump. 3. Close the outlet wall after starting the vacuum pump. 4. Keep the McLeod gauge in horizontal position before starting the vacuum pump. 5. Switch ON the vacuum pump. 6. See the reading in McLeod pump by varying perpendicular axis and note down the

readings.

INTRODUCTION

Low pressure gauge:

Pressure less than 1mm of mercury are considered to be low pressure and are expressed in

either of two units, namely the torr and micron.1 torr is a pressure equivalent to 1mm Hg at

standard conditions., one micron is 10-3

torr through common usage the term vacuum refers to

any pressure below atmosphere (760mm Hg).this pressure region is divided into 5 segments.

Low vacuum 760 torr to 25 torr

Medium vacuum 25 torr to 10-3

torr

High vacuum 10-3

torr to 10-6

torr

Very high vacuum 10-6

torr to 10-9

torr

Ultra high vacuum 10-9

torr and beyond

The pressure measuring devices for low pressure (vacuum) measurement can be classified

into 2 groups

Direct measurement:

Where in displacement deflection costs by the pressure is measured and correlated to the applied pressure. This principle is incorporated in nanometers, spiral bourdon tube; flat and corrugated diaphragms and capsules, manometers and gauges are suitable to about 0.1 torr bourdon gauges to 10 torr and diaphragm gauges to 10-3 torr. Below these ranges, that use of indirect vacuum gauges is resorted. Indirect Measurement (Inferential) gauges wherein the low pressure is detected to measurement of a pressure

controlled property such as volume, thermal conductivity etc., the inferential gauge include

McLeod vacuum meters attention would be concentrated here on low pressure measurement

by the inferential gauges only.

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McLeod gauge The unit comprises a system of glass tubing in which a known volume of gas at

unknown pressure is trapped and then isothermally compressed by raising mercury. This

amplifies the unknown pressure and allows it is measurements by conventional man metric

means.

Tabulation:

S.No. McLeod Gauge Reading

Result: Thus Low pressure measurement is calibrated by using McLeod gauge

EXPERIMENT –11

STUDY AND CALIBRATION OF VIBRATION ANALYSER

AIM: Measurement of vibration parameters.

Apparatus Required: Vibration analyzer, vibration pickup

Procedure: Connect vibration pickup cable to the vibration analyzer sensor socket.

Controls for Vibration meter:

Power on : SPDT switch supplied AC mains into indicator.

Recorder : Screw type connecting terminals to measure the analog readout and recording

purpose.

Sensor : Three pin socket is provided to connect the sensor cable

Function switch : (a) Keep the function switch in to Acc and can be read acceleration 0 to

200 mts/Sec (b)

(c ) Keep the function switch in to displacement and can be read

Power Cable : 3 pin 3 core cable interconnect the 230 Volts/ 50 Hz AC mains into the

instruments. Fuse : 500 MA fuse to protect the instrument from the short circuit.

Output : Analog meter shows according to the function switch kept position reading

displacement or Velocity or Acceleration.

Vibration measuring The instrument which is used tovibrating body are called vibration measuring instruments. Vibration measuring devices having a mass, spring, dashpot etc., are known as seismic instruments. The quantities to be measured are displayed on a screen in the form of electric signal which can be readily amplified and recorded. The output of the electric signal of the instrument will be proportional to the quantity which is to be measured

The above figure shows the potentiometeric typto the wiper arm of resistance potentiometer. The mass is connected to the source of vibration whose characteristics are to be determined. Relative motion of mass with respect to the

Power on : SPDT switch supplied AC mains into indicator.


Sensor : Three pin socket is provided to connect the sensor cable

(a) Keep the function switch in to Acc and can be read acceleration 0 to

200 mts/Sec2

Keep the function switch in to Vel and can be read velocity 0 to

200 mm/sec


displacement 0 to 2000 microns.


instruments.

500 MA fuse to protect the instrument from the short circuit.


displacement or Velocity or Acceleration.

Vibration measuring Instrument: The instrument which is used to measure the displacement velocity or acceleration of a

vibrating body are called vibration measuring instruments. Vibration measuring devices having a mass, spring, dashpot etc., are known as seismic instruments. The quantities to be measured

d on a screen in the form of electric signal which can be readily amplified and recorded. The output of the electric signal of the instrument will be proportional to the quantity which is to be measured

The above figure shows the potentiometeric type accelerometer. The seismic mass is attached to the wiper arm of resistance potentiometer. The mass is connected to the source of vibration whose characteristics are to be determined. Relative motion of mass with respect to the

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(a) Keep the function switch in to Acc and can be read acceleration 0 to

and can be read velocity 0 to




displacement velocity or acceleration of a vibrating body are called vibration measuring instruments. Vibration measuring devices having a mass, spring, dashpot etc., are known as seismic instruments. The quantities to be measured

d on a screen in the form of electric signal which can be readily amplified and recorded. The output of the electric signal of the instrument will be proportional to the quantity

e accelerometer. The seismic mass is attached to the wiper arm of resistance potentiometer. The mass is connected to the source of vibration whose characteristics are to be determined. Relative motion of mass with respect to the

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transducer frame is sensed either as a change in resistance or as a change in voltage output if the potentiometer is used as potential divider. The damping is provided by dash pot. Proper damping is necessary because it increases the range of frequencies over which the transducer may be used.

Vibration measuring principle:

The vibrating probe is stimulated by a piezo and oscillates at its mechanical resonance frequency. If the probe comes into contact with material, the oscillation is dampened and this is electronically registered, and sent out as a signal. Once the probe is no longer comes in contact with material, the probe can oscillate again and a new output signal is generated.

Tabulation:

Acceleration S.No. Displacement Velocity mt/sec

2

microns mm/sec

1 2

3 4

5 6

EXPERIMENT –12

STUDY AND CALIBRATION OF ANGULAR DISPLACEMENT Aim: To study of capacitance transducer for measuring displacement.

Apparatus required: Digital displacement indicator, capacitance pickup.

Procedure:

1. Keep the movable capacitance transducers at 00 points and make 0 by help of

minimum pot. 2. Take the readings to move from 0

0 to 300

0 angle.

3. Make a graph Protractor reading Vs Indicated reading. CONTROLS

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Capacitance sensor: Yellow color sockets provided to connect the capacitance pickup. Zero : 10k single turn potentiometer provided to initiate the Max calibration. CAL: 10 K single turn potentiometer provided to adjusts the Max calibration. Power on: 2 position toggle switch to select the instrument ON or OFF. Power chord: 3 pin provided at back side connect the instruments to the 230V by 50Hz AC supply. Fuse: 500 mA fuse is provided at the back side to protect instruments from the short circuit. D.P.M.: Red color segment LED display read out for digital read out directly in cms.

Tabulation:

S.No. Indicated Reading Protractor Reading

1 2 3

Model graph:

Result: Thus the displacement is calibrated by using capacitance transducer.

Questions: 1. What is meant by displacement?2. What are the uses of capacitive transducer?3. What is meant by capacitance?4. What is meant by transducer?

Protector Reading

Thus the displacement is calibrated by using capacitance transducer.

What is meant by displacement? What are the uses of capacitive transducer? What is meant by capacitance? What is meant by transducer?

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chadalawada ramanamma engineering college · 2018-09-18 · 9 study and calibration of a rotometer...

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