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- 1. PERFORMANCEPERFORMANCE EVALUATION OF CONTROLEVALUATION OF CONTROL VALVESVALVES NIDHIN MANOHAR
2. 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) 3. 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 4. Visual Inspection Casting - 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 finished Valve Seat - Valve seat face shall be free from blow holes Flow passage - Well finished and cleaned EVERY NOOK AND CORNER SHALL BE APPROPRIATELY CHAMFERED OR ROUNDED JIS B 200 3 - 1987 5. Inspection of Dimensions 1. 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 when of 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 face 3. Diameter : ID of valve as per Standard of end openings 4. End to end Dimensions Tolerance on End to End Nominal size of valve Dimensions 250mm and less +/- 2mm 300mm and more +/- 4mm 6. Parallelism of Ends 7. 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 = 8. Nominal Size 50mm and Smaller 20 Larger than 50mm upto and including 15 250mm 30mm and larger 10 9. Misalignment between the axes of the ends shall not exceed 0.5mm / 100mm of end to end dimension Misalignment of Ends 10. 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 11. 7. Test time Nominal Diameter (mm) Test time (sec.) 50 (or) less 15 65 to 200 60 250 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 surface Reference Standards IS 10189 - Part 1 IS 6157 - 1971 JIS B 2003 - 1987 API 598 12. 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 13. Test Procedure for Class II, III and IV Test Medium : Water Test Temperature : Between 10o C and 52o C 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 14. 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 15. Seat Leakage for Class VI Valves Class 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 10-52o C Test Pressure : Maximum rated p or 3.5 bar whichever is less. Allowable Leakage Rate Nominal Port Dia (mm) ML per minute 25 0.15 38 0.30 51 0.45 64 0.60 76 0.90 102 1.70 152 4.00 203 6.75 16. 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 17. 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 18. WATER FLOW LABORATORY TESTING OF VALVES CALIBRATION OF FLOWMETERS RELATED R&D WORKS 19. CALIBRATION PRIMARY METHOD SECONDARY METHOD 20. PRIMARY METHOD USING BASIC PARAMETERS Length Mass Time Temperature (ex.) WEIGHING METHOD VOLUMETRIC METHOD 21. SECONDARY METHOD USING A REFERENCE FLOWMETER ELECTROMAGNETIC FLOWMETERS TURBINE FLOWMETERS INSERTION FLOWMETERS 22. Fig. GRAVIMETRIC WEIGHING SYSTEM 23. B A E G M J L K I H E F F A - Constant head tank - Capacity 50 m^3 B - 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 M F - 4 Low pressure pumps each capable of delivering 1.4 m^3/sec.at 30 M G - Water reservoir - Capacity about 320 m^3 H - Control valve diverter system - Capacity 20 Tonne I - Control valve diverter system - Capacity 2 Tonne J - Weigh tank - Capacity 20 Tonne K - Weigh tank - Capacity 2 Tonne L - Steelyard for weigh bridge M - 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 24. 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 a M P = ( ) 1 1 rhm tx xBxWW Q /33600)12( = 25. FISH TAIL DIVERTOR 26. DETERMINATION OF Cv CHARACTERISTICS The Test Set up Instrumentation Method of Test Cv Calculation Presentation of Result 27. Cv Test set-up 28. INSTRUMENTATION PARAMETERS TO BE MEASURED 1. Differential Pressure 2. Flowrate 3. Upstream Pressure 4. Temperature of Fluid 5. Valve Travel 29. 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 30. 4. Fluid Temperature RTD / Thermometer Accuracy - Within +/- 1 deg.C 5. Valve Travel Dial Gauge / Scale Accuracy - Within +/- 0.5% of Rated Travel 31. 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 32. Cv CALCULATION Where Cv = Valve flow co-efficient Q = Volumetric flow rate dp = Pressure Differential Gf = Liquid specific gravity N1 = Numerical constant for units of measurements used = 0.865 if dp is in Bar and Q is in m3/hr 2/1 1 )( dp Gf N Q Cv = )( 100)( % RatedCv xobtainedCv Cv = TravelRated xTravelValve TravelValve 100 % = 33. Cv Curve