FLOW MEASUREMENT Product Code 316 Instruction manual Contents 1 2 3 4 Description Specifications Installation requirements Installation Commissioning 19-09-2008 5 6 7 8 Troubleshooting Components used Packing slip Warranty Im316 9 Theory 10 Experiments 11 Components’ manuals Page 1 Apex Innovations Description The set up is designed to study following different type of units used for flow measurement. 1) Venturimeter 2) Orifice meter 3) Pitot tube 4) Rotameter 5) Water meter Setup consists of flow measurement units under study, supply tank, Submersible pump for closed loop water circulation, acrylic measuring tank with graduated scale and differential pressure measuring arrangement mounted on stand alone structure. Rotameter Pitot tube Measuring Tank Orifice Venturi Watermeter V2 V1 Pump Specifications Product Product code Venturimeter Orifice meter Pitot tube Rotameter Water meter Supply tank Measuring Tank Pressure difference Pump Piping Overall dimensions Flow Measurement 316 Size 18.5 mm, Bore 10 mm, Acrylic Size 18.5 mm, Bore 12 mm, Acrylic Size 18.5 mm, Acrylic 60-600 LPH Size ½”BSP, brass, Least count 1 lit SS304 Capacity 3 lit, Acrylic Tube with graduated scale Fractional horse power, type submersible ¾“ BSP, CPVC 550Wx475Dx690H mm Shipping details Gross volume 0.31m3, Gross weight 79kg, Net weight 38kg Installation requirements Electric supply Provide 230 +/- 10 VAC, 50 Hz, single phase electric supply with proper earthing. (Neutral – Earth voltage less than 5 VAC) 19-09-2008 Im316 • 5A, three pin socket with switch (1 No.) Water supply Distilled water @10 liters Page 2 Apex Innovations Installation Commissioning INSTALLATION • Unpack the box(es) received and ensure that all material is received as per packing slip (provided in instruction manual). In case of short supply or breakage contact Apex Innovations / your supplier for further actions. • Remove packing wire inserted in the rotameter. • Remove loose components inside the supply tank. Fit small loose pipe to the drain valve provided at the bottom of the measuring tank. Place the supply tank below the set up. • Electric supply: Before connecting electric supply ensure that supply voltage is 230 V AC and earth neutral voltage is less than 5 V Ac. COMMISSIONING • • • • • • • • Remove the supply tank and fill with distilled water. Place the supply tank at its location. Note that the measuring tank drain pipe is inside the supply tank. Ensure that the vent valve on the rubber bulb is fully closed. Fit rotamter outlet pipe Keep the flow regulating valve (V1) 50% open, keep drain valve (V2) 100% open and switch on the pump. Check the working of rotameter by manipulating flow regulating valve (V1) Set the flow rate to 60 lph. Press rubber bulb 2-3 times to lower down the water levels in the manometer tubes. Gently tap the manometer tubes to remove air entrapped. Loosen the vent valve on the rubber bulb slightly. The water shall rise in manometer tubes. Set the water level at mid scale of the manometer. Ensure that total air bubbles are removed by varying the flow rate from minimum to maximum range. (The average level in the manometer can be raised by slightly venting out the air from vent valve of the air bulb or it can be lowered by pumping air by rubber bulb.) NOTE: For longer shut down, remove water from the supply tank and clean it. Troubleshooting Note: For component specific problems refer components’ manual Components used Components Details Rotameter Make Eureka, Model PG 7, Range 60-600 lph, Connection ¾” BSP vertical, screwed, Packing neoprene Make Ananad, Model KNS 15, Class A, Type Multijet, non magnetic, Size 15mm (1/2” BSP) with end connection Submersible pump, Model HQB 4500, Head max. 4.5m, Output 4500 lph, Watts 100, Volts 220-240 Water meter Pump 19-09-2008 Im316 Page 3 Apex Innovations AC, 50Hz Packing slip Box No.1/1 1 2 Size W595xD670xH800 mm; Vol:0.31m3 Set up assembly Instruction manual CD (Apex) 19-09-2008 Im316 Gross weight: 79 kg Net weight: 38 kg 1 No 1 No Page 4 Warranty This product is warranted for a period of 12 months from the date of supply against manufacturing defects. You shall inform us in writing any defect in the system noticed during the warranty period. On receipt of your written notice, Apex at its option either repairs or replaces the product if proved to be defective as stated above. You shall not return any part of the system to us before receiving our confirmation to this effect. The foregoing warranty shall not apply to defects resulting from: Buyer/ User shall not have subjected the system to unauthorized alterations/ additions/ modifications. Unauthorized use of external software/ interfacing. Unauthorized maintenance by third party not authorized by Apex. Improper site utilities and/or maintenance. We do not take any responsibility for accidental injuries caused while working with the set up. Apex Innovations Pvt. Ltd. E9/1, MIDC, Kupwad, Sangli-416436 (Maharashtra) India Telefax:0233-2644098, 2644398 Email: [email protected] Web: www.apexinnovations-ind.com 19-09-2008 Im316 Page 5 Theory 1) Venturimeter The venturi is particularly adapted to installation in pipelines not having long, unobstructed runs. The flow of fluid through the venturi tube establishes the pressure differential, which can then be measured and related to the flow rate. Because of the gradual reduction in the area of flow there is no vena contracta and the flow area is a minimum at the throat so that the coefficient of contraction is unity. The meter is equally suitable for compressible and incompressible fluids. Following figure shows general construction details. Venturimeter Flow Upstream 0 0 19 -23 D/2 d d/2 0 0 7 -15 D Downstream d The flow through the venturimeter and hence through the pipe is given by Q= a1 × a 2 2 gH a12 − a 2 2 Where Q = Theoretical discharge m3/sec. a1 = Area of venturimeter at inlet m2. a2 = Area of venturimeter at throat m2. g = Acceleration due to gravity m/sec2. H = Differential pressure head in m of liquid In actual practice the actual discharge is less than the theoretical discharge. The coefficient of discharge Cd is defined as ratio of actual discharge to theoretical discharge. Coefficient of discharge (Cd) = Actual disch arg e Theoretical disch arg e Thus the equation for actual discharge Qa becomes Q a = Cd X Q a = Cd X a1 × a 2 2 gH a12 − a 2 2 K H where 19-09-2008 Im316 Page 6 K= a1 × a 2 2 g a12 − a 2 2 is known as venturimeter constant. 2) Orificemeter The orifice meter consists of a thin circular metal plate with circular sharp edge hole in it. The concentric orifice is by far the most widely used. As the fluid passes through the orifice, it contracts in area. The minimum flow area is called vena contracta. Different types of taps are used for orifice mete. The flow of fluid through the orifice meter establishes the pressure differential across the orifice plate, which can then be measured and related to the flow rate Orificemeter Orificemeter Flow d Upstream D D/2 D Downstream The Actual discharge through orifice meter is given by Qa = Cc × a 2 gH 1 − Cc 2 (d / D ) 4 Where Qa = Theoretical discharge m3/sec. Cc = Coefficient of contraction a = Area of orifice in m2. g = Acceleration due to gravity m/sec2. H = Differential pressure head in m of liquid d = Diameter of orifice in m. D = Diameter of pipe in m. The above expression can be written as Qa =Cd X a × where Cd = 2 gH Cc 1 − Cc 2 (d / D ) 4 is known as coefficient of discharge 3) Pitot tube The Pitot tube is primarily a device for measuring fluid velocity. It is combination of a total head tube and a static tube. It consists simply of a tube supported in the pipe with the impact opening arranged to point directly towards the incoming fluid. This is called the impact opening and is used to measure the stagnation pressure. The static pressure is measured through the ordinary pressure tap. The difference between impact pressure and static pressure represents velocity head. 19-09-2008 Im316 Page 7 Pressure difference (H) = Velocity head = v2/2g Hence velocity through pipe = Pitot tube 2× g × H Piezometric Static pressure tube Impact Pitot tube pressure Flow D Impact opening 4) Rotameter Rotameter is a variable area meter. In the variable area meter, the drop in pressure is constant and the flow rate is a function of the area of the constriction. A rotameter consists of a tapered tube with the smallest diameter at the bottom. The tube contains a freely moving float, which rests on a stop at the base of the tube. When the fluid is flowing the float rises until its weight is balanced by the up thrust of the fluid, its position then indicating the rate of flow. The area for flow is the annulus formed between the float and the wall of the tube. (The fig. below shows schematic details of rotameter tube and float. Use top edge of the float to note rotameter reading) Rotameter Outlet float stop: To prevent float from leaving flowmeter tube at high flow Maximum flow rate due to maxiimum annular area is obtained at top end of tube Fl u i d p a s s e s th ro u g h th i s a n n u l a r a re a Edge Metering float Tapered glass metering tube Minimum flow rate due to minimum annular area is obtained at bottom end of tube Packing Metering float Flow Inlet float stop: To prevent float from leaving flowmeter tube at no flow 5) Water meter Water meters are used for measuring cumulative water flow. The meter contains a rotating vanes housed in side a cylindrical body. The flow of water through the meter results in the positive displacement of vanes. The water enters in to slotted casing forcing the vanes to rotate about vertical axis. The cumulative flow of water is obtained by gearing rotational motion of the vanes to a counter. 19-09-2008 Im316 Page 8 (The fig. below shows internal construction of water meter. Black digits show cumulative flow in Kiloliters. Next two digits in red show reading in further decimals of kiloliters. The small round dial in red shows reading in liter. The wiper blades can be used for cleaning the cover window from inside.) Watermeter 00000 00 Wiper ,x0.01 9 01 2 3 7 8 Kiloliters 4 56 x1liter Top cover Cover window Rubber packing Gear attachement Support packing Body Water outlet slot Vanes Flow Flow in out Water entry slot Slotted casing 19-09-2008 Im316 Page 9 Experiments 1. TO CALCULATE COEFFICIENT OF DISCHARGE OF VENTURI METER Procedure • Start the set up as explained in commissioning. • Adjust rotameter flow rates in steps of 50 LPH from 60 to 600 LPH and wait for few minutes till the steady state is reached. • Note the pressure difference across the venturi meter. • Close the outlet valve at the measuring tank. • Measure the time required for collecting 1.5 lit of water in measuring tank by stopwatch. • Drain the measuring tank by opening the drain valve (immediately). Observations Sr. No. 1 2 3 4 5 Rotameter Time reqd Actual reading for 1.5 discharge (Lph) liters (sec) (Lph) t 60 100 150 200 Theoretical Coeff. of Reynolds Pressure diff. across discharge discharg Number e Venturi (m) (Lph) H Calculations Venturimeter specification: Inlet pipe diameter (D) Throat diameter (d) Constants: Acceleration due to gravity (g) Quantity of water measured (Q) Density of water (ρ) Viscosity of water (µ) = 0.0185 meter = 0.010 meter = = = = 9.81 m/sec 1.5 X 10 -3 m3. 998 kg/m3 1.00X10-3 kg/m.s Equations used: 1. Inlet area of the venturi meter (a1) = π × D 2 ….m2 4 π 2. Throat area of the venturi meter (a2) = 4 × d …m2 3. Venturimeter constant (K) = 2 a1 × a 2 2 g a12 − a 2 2 Q …m3/sec t 5. Theoretical discharge (QT) = K H …m3/sec 4. Actual discharge (Qa) = 6. Coefficient of discharge (Cd) = Qa / QT 19-09-2008 Im316 Page 10 7. Velocity in pipe (V) = Qa /a1 8. Reynolds No. = ρ.V.D/µ Graphs 1. Coefficient of discharge versus Reynolds number 2. Actual discharge versus theoretical discharge Sample calculations & results Refer worksheet “Venturimeter” in MS Excel file “316.xls” for calculation and graph plotting. 19-09-2008 Im316 Page 11 2. TO CALCULATE COEFFICIENT OF DISCHARGE OF ORIFICE METER Procedure • Start the set up as explained in commissioning. • Adjust rotameter flow rates in steps of 50 LPH from 60 to 600 LPH and wait for few minutes till the steady state is reached. • Note the pressure difference across the orifice meter. • Close the outlet valve at the measuring tank. • Measure the time required for collecting 1.5 lit of water in measuring tank by stopwatch. • Drain the measuring tank by opening the drain valve (immediately). Observations Sr. No. 1 2 3 4 Theoretical Coeff. of Reynolds Rotameter Time reqd Actual Pressure reading for 1.5 discharge diff across discharge discharg Number e (Lph) liter (sec)t (Lph) orifice (m) (Lph) H 60 100 150 200 Calculations Orificemeter specification: Inlet pipe diameter (D) = 0.0185 meter Orifice diameter (d) = 0.0122 meter Constants: Acceleration due to gravity (g) = 9.81 m/sec Quantity of water measured (Q) = 1.5 X 10 -3 m3. Density of water (ρ) = 998 kg/m3 Viscosity of water (µ) = 1.00X10-3 kg/m.s Equations used π 1. Inlet area of the orificemeter (A) = 4 × D …m2 π 2 2. Orifice area of the meter (a) = 4 × d …m2 2 Q …m3/sec t 4. Theoretical discharge (QT) = a × 2 g × H …m3/sec 3. Actual discharge (Qa)= 5. Coefficient of discharge (Cd) = Qa / QT 6. Velocity in pipe (V) = Qa /A 7. Reynolds No. = ρ.V.D/µ Graphs 1. Coefficient of discharge versus Reynolds number 19-09-2008 Im316 Page 12 2. Actual discharge versus theoretical discharge Sample calculations & results Refer worksheet “Orificemeter” in MS Excel file “316.xls” for calculation and graph plotting. 19-09-2008 Im316 Page 13 3. TO CALCULATE COEFFICIENT OF DISCHARGE OF PITOT TUBE Procedure • Start the set up as explained in commissioning. • Adjust rotameter flow rates in steps of 50 LPH from 60 to 600 LPH and wait for few minutes till the steady state is reached. • Note the pressure difference between impact pressure and static pressure. • Close the outlet valve at the measuring tank. • Measure the time required for collecting 1.5 lit of water in measuring tank by stopwatch. • Drain the measuring tank by opening the drain valve (immediately). Observations Sr. No. 1 2 3 4 Rotameter Time reqd Actual Pressure reading for 1.5 discharge difference (Lph) liters (sec) (Lph) (m) H t 60 100 150 200 Theoretical Coeff. of Reynolds discharge discharg Number (Lph) e Calculations Pitot tube specification: Inlet pipe diameter (D) = Constants: Acceleration due to gravity (g) Quantity of water measured (Q) Density of water (ρ) Viscosity of water (µ) 0.0185 meter = = = = 9.81 m/sec 1.5 X 10 -3 m3. 998 kg/m3 1.00X10-3 kg/m.s Equations used π 1. Inlet area of the pitot tube meter: (A) = 4 × D 2 …m2 Q …m3/sec t 3. Theoretical fluid Velocity (V)= 2 × g × H … m/sec 2. Actual discharge (Qa) = 4. Theoretical discharge (QT)= A × V …m3/sec 5. Coefficient of discharge (Cd) = Qa / QT 6. Velocity in pipe (V) = Qa /A 7. Reynolds No. = ρ.V.D/µ Graphs 1. Coefficient of discharge versus Reynolds number 2. Actual discharge versus theoretical discharge Sample calculations & results 19-09-2008 Im316 Page 14 Refer worksheet “Pitot tube” in MS Excel file “316.xls” for calculation and graph plotting. 19-09-2008 Im316 Page 15 4. TO CALIBRATE AND FIND ACCURACY OF ROTAMETER Procedure • Start the set up as explained in commissioning. • Adjust rotameter flow rates in steps of 50 LPH from 60 to 600 LPH and wait for few minutes till the steady state is reached. • Close the outlet valve at the measuring tank. • Measure the time required for collecting 1.5 lit of water in measuring tank by stopwatch. • Drain the measuring tank by opening the drainn valve (immediately). Observations Sr. No. 1 2 3 4 Rotameter reading (Lph) 60 100 150 200 Time reqd 1.5 liters water (sec) for of Actual discharge (Lph) Error (Lph) Accuracy % Calculations 1. Actual discharge = 1.5 × 3600 Time reqd for 1.5 liter water 2. Error = Rotameter reading - Actual discharge 3. Accuracy = Error × 100 Full flow of Rotameter Graphs 1 Plot the graph of Actual discharge versus rotameter reading. 2 Plot the graph of Accuracy versus Rotameter reading. 19-09-2008 Im316 Page 16 5. TO FIND ACCURACY OF WATER METER Procedure • Ensure clean water in supply tank and switch on the pump. • Ensure that the outlet valve at the measuring tank is open. • Adjust rotameter flow rate to say 300 LPH and wait for few minutes till the steady state is reached. • Note the reading of water meter and start the stop watch. • Note the water meter reading after some time interval say 15 minutes. Observations Time interval for which the reading is taken: t minutes Sr. Rotamet *Initial water No. er flow meter rate LPH reading (F) (Liters) A *Final water meter reading (Liters) B Water quantity by water meter (Liters) (B-A) Water Error Accuracy quantity (Liters) (%) by rotameter (Liters) F*t/60 1 2 3 4 *(Please note multiplication factors on the water meter) Calculations 1. Water quantity by water meter = Final water meter reading - Initial water meter reading 2. Error = Water quantity by water meter – Water quantity by rotameter Accuracy = 19-09-2008 Error × 100 Indicated water quantity Im316 Page 17 Components’ manuals Rotameter (PG series) Rotameter works on the principle of variable area. Float is free to move up & down in a tapered measuring glass tube. Upward flow causes the float to take up a position in which the buoyancy forces and the weight are balanced. The vertical position of the float as indicated by scale is a measurement of the instantaneous flow rate. Technical specifications Model Make Flow Rate Max. Packing/Gaskets Measuring tube Float Cover Accuracy Range ability Scale length Max. Temp. Connection PG-1 to 21 Eureka Industrial Equipments Pvt. Ltd. 4000 to 40000 Lph Neoprene Borosilicate glass 316SS Glass +/-2% full flow 10:1 175-200mm. 2000C Flanged and Threaded, Vertical Principle of operation The rotameter valves must be opened slowly and carefully to adjust the desired flow rate. A sudden jumping of the float, which may cause damage to the measuring tube, must be avoided. Fig.1 Edge The upper edge of the float as shown in fig. 1 indicates the rate of flow. For alignment a line marked R.P. is provided on the scale which should coincide with the red line provided on measuring tube at the bottom. Maintenance When the measuring tube and float become dirty it is necessary to remove the tube and clean it with a soft brush, trichloroethylene or compressed air. Dismantling of the measuring tube • Shut off the flow. • Remove the front and rear covers. • Unscrew the gland adjusting screws, and push the gland upwards incase of bottom gland and downwards incase of top gland. Then remove the glass by turning it to and fro. Care should be taken, not to drop down the glands. Float or float retainers. The indicating edge of the float should not be damaged. 19-09-2008 Im316 Page 18 Fitting of the measuring tube Normally the old gland packing is replaced by new ones while fitting back the measuring tube. • Put the glands first in their position and then put the packing on the tube. • Insert the tube in its place. • Push the glands downwards and upwards respectively and fix them with the gland adjusting screws. • Tighten the gland adjusting screws evenly till the gap between the gland and the bottom plate is approximately 1mm. In case, after putting the loflometer into operation, still there is leakage, then tighten the gland adjusting screw till the leakage stops. • Fix the scale, considering the remark given in the test report. • Fix the front and rear covers. Troubleshooting Problem Leakage on glands Showing high/low flow rate than expected Showing correct reading initially but starts showing high reading after few days Showing correct reading initially but starts showing high reading after some months. Fluctuation of float Check Replace gland packing Consult manufacturers Replace float Incase of gases, check also leakage Clean the rotameter by suitable solvent or soft brush Maintain operating pressure as mentioned in test report. Use loflometer to accommodate correct flow rate. Maintain operating pressure below pressure rating of the tube. Check piping layout. Frequent breakage of glass tube Manufacturer’s address If you need any additional details, spares or service support for this unit you may directly communicate to the manufacturer / Dealer / Indian Supplier. Eureka Industrial Equipments Pvt. Ltd. 17/20, Royal Chambers, Paud Road, Pune – 411 038. Email: [email protected] 19-09-2008 Im316 Page 19
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