Overview of Meter Proving
and Calibration
for
The influence of vapor on calibration
Gasoline Inventory Challenges
Fuel Terminal to Automobile Tank
.
Automobile Improvements
(Background Information)
• The automobile industry has
implemented the Onboard
Refueling Vapor Recovery
System (ORVR). They call it
“Capless Fueling” or “Easy Fuel”.
• ORVR was required by the
Federal Government to be
installed in all newly
manufactured vehicles in 2004.
• The new system enables the
vapors that were once vented into
the air or captured by the Stage II
Vapor recovery system to be
retained inside the automobile and
used to fuel the engine.
• The significance of this is that
there is not anymore vapor lost
at the fill neck of an automobile
when refueling.
Components in a positive displacement meter
(Background Information)
Cylinder Wall
Piston Cup
Piston Roller
Camshaft
Cam
Meter Wear
Primary Causes of Unaccounted Fuel Slippage
(Dispensing More Than What is Registered):
1.
2.
3.
4.
•
•
Wear to the piston cups and the cylinder walls.
Wear between the valve seat, valve, and counter-valve (when present).
Wear to the cam and the piston roller assemblies.
Wear to the camshaft bearings, valve keyhole & key (when present).
How Meters Wear
Over time, the various surfaces which rub against one another will wear and
result in minute changes in the dimensions of the various components. Also, if
there is grit present in the fuel, the rate of wear will be greatly accelerated. In
many older meters, there is a center cavity in which debris can be trapped,
accumulate, and can accelerate wear to piston cups and cylinder walls, camshaft
bearings, piston roller assemblies, and the cam.
Source PMP Corporation
Manufacturer’s recommended calibration schedule
• Source Gilbarco
Open Neck Prover Method of Operation
• Fill Prover with 5
gallons of gasoline.
• View product level on
the meniscus.
• Determine variance
How does vaporization impact meter
calibration?
• When using an open neck prover a
small amount of fuel is vaporized
when dispensing fuel in the prover.
• The fuel that is vaporized is not in
the prover. Therefore it appears on
the miniscus of the prover that
vaporized fuel was not dispensed
because it is not in the prover.
• The reality is that it was dispensed
however it vaporized
Vapor Elimination Prover (VEP)
Specialized Prover used by Crompco’s AccuMeasure Crews
Running Multiple Tests is Important
•
•
•
•
•
The first 5 gallons cannot be used for accurate meter proving. (see above)
Crompco does run a second Fast Flow Test on each meter to ensure repeatability.
A Slow Flow Test is run on every meter prior to sealing the meter.
As a result a minimum of 20 gallons is run per meter.
Approximately 6 meters per store required calibration to be completed twice or
more in order to achieve repeatability within the .5 in³ protocol.
Benefits of the VEP
• VEP eliminates the effects of vaporization in meter proving.
• The system is very repeatable which will enable the technician
to calibrate meters to “0”.
• VEP is designed & built to National Institute of Standards &
Technology Handbook 105-3 Specifications.
– This means it is accredited by NIST & approved by all
W&M Agencies.
– The results are traceable to NIST’s National Standards.
• The provers are exclusively developed by Seraphin for
Crompco.
Math Behind Metering
• We have studied the effects of vaporization on
calibration and determined that vaporization
accounts for approximately .2% of product loss
during meter testing/calibration.
• How much is .2%?
– .2% of 5 gallons (which is 1155 in³) is .010 gallons
(2.31 in³) per five gallons.
– .2% of 1,000,000 gallons is 2,000 gallons
• Our goal with AccuMeasure is to save as much
of the vapor/gasoline loss as possible.
Corresponding Gasoline Inventory
to AccuMeasure Results
•
•
•
•
The loss trend on both
products change after
AccuMeasure was
completed.
The stage II vapor
recovery causes an
increase in fuel
especially on the
Regular product.
The calibration
improved the Regular
by approximately 309
gallons per month.
The site pumps
approximately
1,041236 gallons per
year
Meter Variance & Product Loss
METER VARIANCE -- PRODUCT "GIVE AWAY" or "HOLD BACK" -- CUBIC INCHES
Site Volume
G a llo ns
pe r Y e a r
50,000
100,000
200,000
300,000
400,000
500,000
600,000
700,000
800,000
900,000
1,000,000
1,100,000
1,200,000
1,300,000
1,400,000
1,500,000
1,600,000
1,700,000
1,800,000
1,900,000
2,000,000
2,250,000
2,500,000
2,750,000
3,000,000
3,500,000
4,000,000
4,500,000
5,000,000
G a llo ns
pe r M o nt h
4,167
8,333
16,667
25,000
33,333
41,667
50,000
58,333
66,667
75,000
83,333
91,667
100,000
108,333
116,667
125,000
133,333
141,667
150,000
158,333
166,667
187,500
208,333
229,167
250,000
291,667
333,333
375,000
416,667
G a llo ns pe r
D ay
137
274
548
822
1,096
1,370
1,644
1,918
2,192
2,466
2,740
3,014
3,288
3,562
3,836
4,110
4,384
4,658
4,932
5,205
5,479
6,164
6,849
7,534
8,219
9,589
10,959
12,329
13,699
0.5
22
43
87
130
173
216
260
303
346
390
433
476
519
563
606
649
693
736
779
823
866
974
1,082
1,190
1,299
1,515
1,732
1,948
2,165
1
43
87
173
260
346
433
519
606
693
779
866
952
1,039
1,126
1,212
1,299
1,385
1,472
1,558
1,645
1,732
1,948
2,165
2,381
2,597
3,030
3,463
3,896
4,329
1.5
65
130
260
390
519
649
779
909
1,039
1,169
1,299
1,429
1,558
1,688
1,818
1,948
2,078
2,208
2,338
2,468
2,597
2,922
3,247
3,571
3,896
4,545
5,195
5,844
6,494
2
2.5
87
173
346
519
693
866
1,039
1,212
1,385
1,558
1,732
1,905
2,078
2,251
2,424
2,597
2,771
2,944
3,117
3,290
3,463
3,896
4,329
4,762
5,195
6,061
6,926
7,792
8,658
108
216
433
649
866
1,082
1,299
1,515
1,732
1,948
2,165
2,381
2,597
2,814
3,030
3,247
3,463
3,680
3,896
4,113
4,329
4,870
5,411
5,952
6,494
7,576
8,658
9,740
10,823
3
130
260
519
779
1,039
1,299
1,558
1,818
2,078
2,338
2,597
2,857
3,117
3,377
3,636
3,896
4,156
4,416
4,675
4,935
5,195
5,844
6,494
7,143
7,792
9,091
10,390
11,688
12,987
3.5
152
303
606
909
1,212
1,515
1,818
2,121
2,424
2,727
3,030
3,333
3,636
3,939
4,242
4,545
4,848
5,152
5,455
5,758
6,061
6,818
7,576
8,333
9,091
10,606
12,121
13,636
15,152
4
173
346
693
1,039
1,385
1,732
2,078
2,424
2,771
3,117
3,463
3,810
4,156
4,502
4,848
5,195
5,541
5,887
6,234
6,580
6,926
7,792
8,658
9,524
10,390
12,121
13,853
15,584
17,316
4.5
195
390
779
1,169
1,558
1,948
2,338
2,727
3,117
3,506
3,896
4,286
4,675
5,065
5,455
5,844
6,234
6,623
7,013
7,403
7,792
8,766
9,740
10,714
11,688
13,636
15,584
17,532
19,481
5
216
433
866
1,299
1,732
2,165
2,597
3,030
3,463
3,896
4,329
4,762
5,195
5,628
6,061
6,494
6,926
7,359
7,792
8,225
8,658
9,740
10,823
11,905
12,987
15,152
17,316
19,481
21,645
5.5
238
476
952
1,429
1,905
2,381
2,857
3,333
3,810
4,286
4,762
5,238
5,714
6,190
6,667
7,143
7,619
8,095
8,571
9,048
9,524
10,714
11,905
13,095
14,286
16,667
19,048
21,429
23,810
6
260
519
1,039
1,558
2,078
2,597
3,117
3,636
4,156
4,675
5,195
5,714
6,234
6,753
7,273
7,792
8,312
8,831
9,351
9,870
10,390
11,688
12,987
14,286
15,584
18,182
20,779
23,377
25,974