testing of valves.maximum share.....!!

PERFORMANCE PERFORMANCE EVALUATION OF CONTROL EVALUATION OF CONTROL

VALVESVALVES

NIDHIN MANOHAR

TESTING OF VALVES• ROUTINE TESTS

– MATERIAL TEST

– VISUAL INSPECTION

– DIMENSIONAL CHECK

– HYDRAULIC PRESSURE TEST

– GLAND LEAKAGE TEST

– SEAT LEAKAGE TEST

• TYPE TESTS– VALVE FLOW CO-EFFICIENT (CV)

– INHERENT FLOW CHARACTERISTICS

– LIQUID PRESSURE RECOVERY FACTOR (FL)

– PIPING GEOMETRY FACTOR (FP)

MATERIAL TEST

– INSPCTION OF MATERIAL SHALL BE CONDUCTED IN ACCORDANCE WITH THE MATERIAL SPECIFICATIONS

– THE MATERIAL OF WHICH QUALITY HAS BEEN ASCERTAINED MAY BE EXEMPTED FROM THE MATERIAL TEST

Visual InspectionCasting - Shall be free from blow holes, fins, sand

burning, sand holes, scale, cracks etc.Forging - Shall be free from Laps, setting down

flaws etc.Machining - Shall be free from harmful defects.surface Shall be uniformly finishedValve Seat - Valve seat face shall be free from blow holesFlow passage - Well finished and cleaned

EVERY NOOK AND CORNER SHALL BEAPPROPRIATELY CHAMFERED OR ROUNDED

JIS B 200 3 - 1987

Inspection of Dimensions1. Ends : Flange diameter, flange thickness, flange

facings, flange drilling, spot facing, threads and welding end dimensions - as per Std.

2. Flatness : The flatness shall be in such a way that whenof face a straight edge is placed on the face, a feeler

strip of 0.15mm shall not enter anywhere between the straight edge and the contact

face3. Diameter : ‘ID’ of valve as per Standard of end openings4. End to end Dimensions Tolerance on End to End

Nominal size of valve Dimensions 250mm and less +/- 2mm

300mm and more +/- 4mm

Parallelism of Ends

Contact faces - In case of flanged and butt welding ends

Plain or Threaded bores - In case of screwed and socket

welding ends. To be inspected

Nominal Size 50mm and Smaller 20’

Larger than 50mm upto and including 250mm 15’

300mm and larger 10’

)D

AA(Tan 121

Nominal Size

50mm and Smaller 20’

Larger than 50mm upto and including 15’

250mm

30mm and larger 10’

Misalignment between the axes of the ends shall not exceed

0.5mm / 100mm of end to end dimension

Misalignment of Ends

Hydraulic Pressure Test (OR) Shell test

1. Control valve without painting shall be tested

2. Valve ends - Closed

3. Valve opening- Partial

4. Gland packing - Sufficiently tight to maintain the test

pressure

5. Test temperature - Ambient

6. Test pressure - 1.5 times of rated pressure

7. Test time

Nominal Diameter (mm) Test time (sec.)50 (or) less 1565 to 200 60250 or over 180

At intervals of 5 seconds the valve shall be tapped with a soft hammer

There shall be no leakage or wetting of surfaceReference StandardsIS 10189 - Part 1IS 6157 - 1971JIS B 2003 - 1987API 598

Gland Leakage Test

This test shall be made consecutively with shell test or

hydraulic pressure test

Seat Leakage Test

ANSI B 16.104 - Control valves seat leakage

Class I : Modification of Class II, III or IV. No test is required

Class II : 1. Double seat control valves

2. Balanced single port with piston and metalto metal seats

Class III : 1. Class II with higher degree of seat and seal tightness

Class IV : 1. Unbalanced single port single seat

2. Balanced single port with extra tight piston rings or

other sealing means and metal to metal seats

Test Procedure for Class II, III and IV

Test Medium : Water

Test Temperature: Between 10oC and 52oC

Test Pressure : 3 - 4 bar or maximum operating p

whichever is less

Valve Position : Fully closed, outlet open to Atm. Pressure

applied at valve inlet

Leakage rate shall be within the following vales

Class II - 0.5% of rated capacity

Class III - 0.1% of rated capacity

Class IV - 0.01% of rated capacity

Flowrate Data - Accurate to +/- 10% of Reading

Seat Leakage Test for Class V Valves

Class V Valves : Metal seat, unbalanced single port, single seat or

balanced single port with exceptional seat and seal tightness

Test Procedure : Same as than for Class II, III and IV valves except

the following.

Test Pressure : Maximum service p not exceeding the maximum

operating pressure (“ 7 Bar” pressure drop

minimum”

Allowable Leakage Rate - 5 x 10-4 ml / min

Seat Leakage for Class VI ValvesClass VI Valves : Resllient seating control valve either unbalanced

or balanced single port with ‘O’ rings or similar gapless seals

Test Procedure Test medium : Air or Nitrogen gas at 10-52oCTest Pressure : Maximum rated ‘p ‘ or 3.5 bar whichever is less.Allowable Leakage RateNominal Port Dia (mm) ML per minute25 0.1538 0.3051 0.4564 0.6076 0.90102 1.70152 4.00203 6.75

FLOW TEST ON VALVES

• Introduction• The Water Flow Test Facility of FCRI• Test for Cv - Characteristics• Test for FL - Characteristics• Test for Torque Characteristics• Test for Pressure Drop - Flow Characteristics• Conclusion

INTRODUCTION TO THE WATER FLOW TEST FACILITY OF FCRI

• Basic Method Adopted for Flow Measurement• The Water Flow Test Facility• Method of Flow Measurement• Flow Rate Calculation• Overall Uncertainty

WATER FLOW LABORATORY

• TESTING OF VALVES

• CALIBRATION OF FLOWMETERS

• RELATED R&D WORKS

CALIBRATION

• PRIMARY METHOD

• SECONDARY METHOD

PRIMARY METHOD

• USING BASIC PARAMETERS– Length– Mass– Time– Temperature

• (ex.) WEIGHING METHOD

• VOLUMETRIC METHOD

SECONDARY METHOD

• USING A REFERENCE FLOWMETER– ELECTROMAGNETIC FLOWMETERS– TURBINE FLOWMETERS– INSERTION FLOWMETERS

Fig. GRAVIMETRIC WEIGHING SYSTEM

B

A

E

G

M

JL

K

I

H

EF

F

A - Constant head tank - Capacity 50 m^3B - Duplex filter - 600mm N.B.C - Electromagnetic flow meter - 300mm dia.D - Electromagnetic flow meter - 150mm dia.E - 2 High pressure pumps each capable of

delivering 0.125 m^3/sec.at 100 MF - 4 Low pressure pumps each capable of

delivering 1.4 m^3/sec.at 30 MG - Water reservoir - Capacity about 320 m^3H - Control valve diverter system - Capacity 20 TonneI - Control valve diverter system - Capacity 2 TonneJ - Weigh tank - Capacity 20 Tonne

K - Weigh tank - Capacity 2 TonneL - Steelyard for weigh bridgeM - Overflow return line

Schematic of Water flow laboratory

C

D

F

F

L

Test lines (100mm to 600mm)

900mm Test line

N - Electromagnetic flow meter - 600mm dia.

N

CALCULATION OF FLOW RATE

where Q - Volumetric flow rate (m3/hr)

W1 - Initial mass of weigh tank (Kg)

W2 - Final mass of weigh tank (kg) t - Collection time (Sec) - Density of water (kg/m3) (Density of distilled water at line temperature x Relative density of water) B - Buoyancy correction factor (B = 1 + E = 1.00106,

OVERALL UNCERTAINTY = BETTER THAN +/- 0.1%

E aM P

( )1 1

rhmtxxBxWWQ /33600)12(

FISH TAILDIVERTOR

DETERMINATION OF Cv CHARACTERISTICS

• The Test Set up

• Instrumentation

• Method of Test

• Cv Calculation

• Presentation of Result

Cv Test set-up

INSTRUMENTATION

• PARAMETERS TO BE MEASURED

1. Differential Pressure

2. Flowrate

3. Upstream Pressure

4. Temperature of Fluid

5. Valve Travel

1. Differential Pressure Pressure gauge / Pressure Transducer Accuracy - Within +/-2% of Actual value

2. Flow rate Gravimetric method / Reference flowmeter Accuracy - Within +/- 2% of Actual value

3. Upstream Pressure Pressure gauge / Pressure Transducer Accuracy - Within +/- 2% of Actual value

4. Fluid Temperature

RTD / Thermometer

Accuracy - Within +/- 1 deg.C

5. Valve Travel

Dial Gauge / Scale

Accuracy - Within +/- 0.5% of Rated Travel

Cv TEST METHOD• Valve Travel 100%• Differential Pressures a) Just below the onset of cavitation or the maximum available in the test facility whichever is less b) About 50% of (a) c) About 10% of (a)• Mean Cv• % Cv• % Valve Travel

Cv CALCULATION

Where Cv = Valve flow co-efficientQ = Volumetric flow ratedp = Pressure DifferentialGf = Liquid specific gravityN1 = Numerical constant for units of measurements used = 0.865 if ‘dp’ is in ‘Bar’ and ‘Q’ is in m3/hr

2/1

1

)(dpGf

NQ

Cv

)(100)(

%RatedCv

xobtainedCvCv

TravelRatedxTravelValve

TravelValve100

%

Cv Curve