The LectroCount LCR Electronic Register Controls Calibration... · filling a tank of a known volume at various flowrates. Multiple “proving” runs are taken at each flow rate to

Calibration

Calibration

Flow Meter Calibration or “Proving”

We are going to discuss two methods of meter calibration:

Volumetric (or tank) Proving

&

Master Meter Proving

LINEARITY AND REPEATABILITY

The 5:1 turndown ratio has the most

narrow linearity range, +/- .125%

The 10:1 turndown ratio has a

linearity range of +/-.22%

The 40:1 turndown ratio has a

linearity range of +/-.50%

Repeatability is .05%

There are 2 adjustments for the mechanical register:

•Coarse •Fine

The Coarse adjustment is the register gear plate. The Fine Adjustment is the standard adjuster.

The gear plate is calculated ahead of time and is installed prior to calibration. Each meter size and unit of measure for each meter size requires different ratio gear plates.

Calibrating the Meter equipped with a Mechanical Register

The LC Adjuster

The Liquid Controls Adjuster is a +/- 2.5% infinitely variable speed transmission. It allows the user to change the meter out put to the required meter reading for a known volume.

CALIBRATION, PRACTICAL ASPECTS Volumetric proving is defined as

filling a tank of a known volume

at various flowrates. Multiple

“proving” runs are taken at each

flow rate to establish linearity

and repeatability.

Volumetric provers are

considered primary standards

and when used with proper

temperature and pressure

measurement achieve “standard

volume measurements”.

VOLUMETRIC PROVING

Proving techniques are well defined by organizations such as

the American Petroleum Institute (API).

Here are some important proving issues:

The meter must be thermally

stable before the prover runs are

made. Run the meter to assure it is

at the same temperature as the

product.

VOLUMETRIC PROVING Keep the meter to

be proven as close

to the prover as is

possible. This

minimizes

temperature

differences between

the meter under test

and the prover.

VOLUMETRIC PROVING

Volumetric proving requires temperature

measurement at the prover and in the

process line adjacent to the meter under

test.

It also requires system pressure readings

taken during the proving run.

These measurements allow the calculation

of a base temperature volume.

VOLUMETRIC PROVER REPORT LCIL order number: N/A

Type of Test Master Master Master Master Master Master Master Master Master

Prover Size (Ltr) 5000 5000 5000 5000 5000 5000 5000 5000 5000

Flow Rate (Ltr/Min) 1200 1200 1200 850 850 850 500 500 500

Meter Temp (15%) 29.7 29.8 30.2 30.9 31.2 31.5 32.1 32.6 33.1

Meter Temp (50%) 29.6 29.9 30.2 30.9 31.3 31.5 32.1 32.6 33.2

Meter Temp (85%) 29.6 30 30.2 30.9 31.3 31.5 32.1 32.6 33.3

Avg. Prover Temp (C) 29.5 29.8 30.07 30.8 31.13 31.47 31.97 32.47 33.1

Prover Reading (Ltr) 5003.9 5003.8 5002.2 5003 5000.9 5000.6 5000.7 5000 5001.5

Meter Reading (Raw Pulses) 96898 96903 96868 96913 96865 96868 96860 96841 96870

Meter Pressure (Kg/cm2) 2.364 2.364 2.364 3.145 3.145 3.145 3.35 3.35 3.35

Prover Tank Volume Data

Correcton Factor Cts 1.0005 1.0005 1.0005 1.0005 1.0005 1.0005 1.0005 1.0006 1.0006

Correction Factor Ctl 0.9976 0.9974 0.9971 0.9966 0.9961 0.9958 0.9953 0.9950 0.9942

Combined Correction Factor 0.9981 0.9979 0.9976 0.9971 0.9966 0.9963 0.9958 0.9956 0.9948

Corrected Prover Volume (liter) 4994.221 4993.170 4990.117 4988.535 4983.994 4982.251 4979.932 4977.817 4975.412

Meter Data

Ctl use 1.000 if Temp Compensated 0.9976 0.9974 0.9971 0.9963 0.9961 0.9958 0.9953 0.9947 0.9942

Cpl 1.0002 1.0002 1.0002 1.0003 1.0003 1.0003 1.0003 1.0003 1.0003

Combined Correction Factor 0.9978 0.9976 0.9973 0.9969 0.9964 0.9961 0.9956 0.9953 0.9945

Corrected Meter Volume (Pulses) 96686.808 96672.444 96608.526 96612.154 96515.942 96489.905 96435.504 96387.617 96339.099

Corrected Pulses/Litre 19.3597369 19.36093493 19.3599707 19.3668406 19.36518043 19.3667303 19.3648236 19.36343002 19.3630391

Average Pulses per Flowrate 19.3602 19.3663 19.3638

Average Percent Error 0.0312% 0.0000% 0.0128%

Repeatability 0.0031% 0.0043% 0.0046%

Flow Rate (GPM/LPM) 317 1200 225 850 132 500

Calibration Points 0.03% 0.00% 0.01%

K Factor (ideal) 19.3

Meter factor @ Flowrate 0.996890 0.996579 0.996707

flow rate (LPM) 1200.00 850.00 500.00 150.00 150 150

%error 0.031% 0.000% 0.013% -0.069% -0.069% -0.069%This is a prover report for a 3” meter under test against a volumetric prover. Note that temperatures are taken in the piping adjacent to the meter at 15%, 50% and 85% of the prover fill. Additionally the temperatures are taken at three points within the 5000 liter prover and averaged. Without temperature and pressure correcting, tank proving is not going to be accurate. Refer to API Chapter 4 for best practices in proving.

A Master Meter in Series with a Meter to be Calibrated

MASTER METER PROVING

The master meter is simply a meter that has been proven

against a primary standard. Select meters that have the best

repeatability.

MASTER METER PROVING

The characteristic of the master is defined

by the primary standard.

The master can then be used to prove the

meter under test. Because both the master

and the meter under test are at the same

temperature and pressure these effects do

not need to be considered in master

proving.

MASTER METER PROVING

The master meter and

the meter under test

need to be as close

together as is

reasonable. Long

distances (50 or 60

meters) is not advisable

because of possible

temperature changes

between the two units.

Master Meter Proving P.D.Meter Model : MSAA-30-P-01 Pulser Model : VS-300 Master Meter Model : MS-30-P-01

P.D.Meter Sr. No. : 419 Pulser Sr.No.: 4798 Master Meter Sr.No. : 152/97

Meter Element No. : 342765 Date : 24th Dec. '97 Calibrated at LCIPL

Base K-Factor = 19.30 Pulses/Liter

Master Mtr. Indicated Average

Sr. Flow Rate K-Factor Master Rdg. Master Rdg. Test Rdg. Test Rdg. Meter Meter Repeatability

No. LPM Pulses/Liter Pulses Liter Pulses Liter Factor Factor

1 1200 19.3907 34840 1796.74 34798 1803.01 0.99652

2 1200 19.3907 34898 1799.73 34855 1805.96 0.99655 0.99653 0.00

3 1200 19.3907 35043 1807.21 35001 1813.52 0.99652

4 850 19.3950 25183 1298.43 25158 1303.52 0.99609

5 850 19.3950 25257 1302.24 25234 1307.46 0.99601 0.99601 0.01

6 850 19.3950 25220 1300.34 25199 1305.65 0.99593

7 500 19.4010 19434 1001.70 19418 1006.11 0.99561

8 500 19.4010 19495 1004.85 19482 1009.43 0.99546 0.99553 0.01

9 500 19.4010 19353 997.53 19339 1002.02 0.99551

10 150 19.4063 19392 999.26 19384 1004.35 0.99493

11 150 19.4063 19350 997.10 19344 1002.28 0.99483 0.99488 0.01

12 150 19.4063 19464 1002.97 19457 1008.13 0.99488

Linearity = +/- 0.09

Calibrated by : Approved by :

Customer :

End User : Calibration Report for Meter with Electronic Pulser

Consultant : Liquid Controls India Pvt. Ltd.

EIL Job No.:

This is an actual Meter tested against a Master. The turn down is essential 10:1 and we are using pulse counts only for the purpose of calibration. The linearity shown is a +/- value so the total deviation for this meter is .18% through the test range. The linearity is taken from the highest and lowest values from the meter factor column. It is not taken from the average of the meter factors at each flow rate. The repeatability is what we normally expect from a meter.

Master Meter Proving

This is the same meter as the previous slide but installed in the field after one year of operation. It appears that the meter has gotten quite a bit better! Be careful! The product is different than in the factory and the range of flow rates is very narrow. Be very, very careful when reviewing the proving data. The product used in this test was diesel where as the product in the factory is similar to kerosene.

SOME THINGS TO WATCH WHEN MASTER

METER OR VOLUMETRIC PROVING

System product temperatures should

remain within 5 degrees F during the

proving runs.

System temperatures should be below 100

degrees F for products similar to Diesel

and Kerosene. Above this temperature,

product flashing may occur affecting the

calibration.

SOME THINGS TO WATCH WHEN MASTER

METER OR VOLUMETRIC PROVING

Complete the proving of a meter in one

session. Do not run half of the runs in the

afternoon and the rest of the runs the

following morning.

Make sure the meters under test are

properly filled, air bled and temperature

stabilized before proving.