1/21/2020 LPG Dispensers

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General Rules
Verification of auto LPG Dispensers State Enforcement Rules
Part IV of the Eighth Schedule, The Legal Metrology (General) Rules, 2011 REGISTRATION
Specific provision: Part 2 Rule 5(7) Nomination
Verification & Stamping
The type of LPG used as a motor License
vehicle fuel is a liquid mixture L P G as A u t o - f u e l
Approval of Model
containing at least 90 percent LPG exists as a gas at atmospheric Addresses of LM
propane, 2.5 percent butane and pressure and temperature. Authorities
higher hydrocarbons, and the balance LPG is supplied at a pressure of 7 -
is ethane and propylene. The mixture 10 bar (700 - 1000 Kpa)
is genetically named as propane but 1 kg of LPG normally has a volume Techni cal Gui des
commonly referred to as LPG of 1.835 litres at 30°C but the NA Weighing Instruments
(Liquified Petroleum Gas ). It is sold volume varies with change of Testing and Sealing NAWI
by volume and not by weight as in temperature. The volume is 1.724 Digital Balance
domestic LPG. litres at 15°
Road Weigh-bridge
The LPG dispensers are classified as Class 1.0 instrument with
Liquid Fuel Dispensers
MPE limit of ±1%
Petrol/Diesel Dispensers
Sealing Dispensers
Essential Components L.P.G. Dispensers
C.N.G. Dispensers
The Metering Unit Rail Weigh-bridge
Vehicle Tank

The metering unit consists of a meter and a transducer (sensor) Storage Tank

device. The meter has a system for mechanical adjustment or Net Content Checking
calibration.

A Solenoid valve is also often employed to control the flow of liquid. PC Noti fi cati ons
The Second Schedule
It also contains a calculator along with a memory device for Amendment 2017
recording quantity delivered. GSR 629(E) dated
A typical meter A typical sensor
23.06.2017

Processing Unit Amendment 2016

GSR 858(E) dated
It controls the functions and operation of the metering, display and registering units and all peripheral ancillary 07.09.2017
devices like preset, price calculator and printers. It also includes a calibration card to control the delivery of fuel Amendment 2015
from the dispenser. GSR 385(E) dated
14.05.2015

Display Unit 2nd Amendment 2014

GSR 870(E) dated
The display unit consists of 04.12.2014
1st Amendment 2014
a Totalizer Unit Price Indicator GSR 137(E) dated
a Volume Indicator Total Price Indicator 16.06.2014
1st amendment of 2013:
GSR. 359(E) dated
Verification Procedure
06.06.2013

The LM (General) Rules does not prescribe any procedure for testing and verification at user level. The GSR. 426(E) dated
following is based on practices followed internationally. 05.06.2012
GSR. 427(E) dated
Preliminary Checking 05.06.2012

Whether the instrument comply with the Certificate of Model Approval

Whether all mandatory descriptive markings are clearly indicated on the fixed plate for stamping
(Refer to Liquid Dispensers for statutory markings.)
Do the indication of volume, unit price and total price corresponds with each other and related to the selected nozzle.
Are all the indications are clearly visible under any condition of day and night.

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Are all the hoses and the nozzles are in good condition
Is there any leak any where

C h e cking D e v i c e s

Indicating Devices Zero-Setting

The checking of Indicating devices consists of visual checking of The Zero Setting Devices of Price
the entire display. Indicating and Volume Indicating
Displaying all the elements ("eights" test) Device will be such that when one is
Blanking all the elements set to zero, the other will automatically
Displaying the Zeros reverted to Zero.
The Zero-Setting Device shall not be
This test is performed by looking at the indicators before and after removing capable of changing the result except
the nozzle from its rest position. Ensure that the price and volume displays
entirely removing it and setting to zero.
are on zero before any delivery is possible.

Preset Indications
Price Computing
Some systems employ Volume and Price pre-setting devices. Such
devices stops flow of fuel passing through the nozzle when the The Price-Indicator should show the
price or volume correspondences with the preset value. result of volume multiplied by unit
price indicated. This test may be done
Set the dispenser to zero.
Enter a preset value of volume.
during a test delivery for checking
Start delivery of the volume and check the volume with a measuring accuracy.
can. The delivery from the nozzle should not stop until the preset If the dispenser issues a printed
volume is reached. receipt, the printed values of volume,
The test will also be carried out for preset Price Indicator. The price will unit price and total price must be same
be divided by the unit price to calculate the volume and the volume will as shown on the display panels.
be compared with the actual delivery and volume indicator reading.

Checking Accuracy

Methods employed for testing accuracy of an LPG measuring device may be Volumetric or Gravimetric.

Volumetric Method
The volumetric method uses a master meter or a mass flow-meter as the reference standard.

Advantages Disadvantages
Since LPG is sold by volume, it is a direct, the most Unavailability of Meter
efficient and reliable method Meter cost is high
Gas disposal is not a problem Meter calibration facilities not always
Fast, secure and safe available.

Preliminary Steps
E q u ipmen t
The tests should made between 0 to 30° C to minimize
expansion of LPG due to temperature. Certificate/s of approval.
Connect the dispenser nozzle to the Master Meter. A master meter or mass flow-meter (±0.2% mpe)
Connect the Meter nozzle to the maintenance port or return with reference standard thermometer (±0.2°C
passage of the dispenser. mpe) and 2 500 kPa reference standard
Note the Totalizer reading. pressure gauge (±25 kPa mpe) fitted to the inlet
Circulate at least 100 litres of LPG to balance any of the master meter.
temperature difference between the meter and the A hydrometer pressure vessel with a reference
dispenser. standard hydrometer (mpe of ±1 kg/m3 for
Check if the Totalizer is functioning properly.
master meters and ±0.5 kg/m3 for mass flow-
Enter a value on the Preset (if present) and observe the
meters), a reference standard thermometer
delivery. Towards the end of delivery, the rate of flow should
(±0.2°C mpe) and a 2 500 kPa reference
slow down and stop at the setting.
standard pressure gauge (±25 kPa mpe).
The dispenser and the Meter may be fitted with ATC
A reference standard thermometer (±0.2°C mpe)
(Automatic Temperature Compensation). Ensure that ATC is
suitable for inserting into the thermo-well of the
either active on both the instruments or inactive in the both.
dispenser.
At this stage, turn off the valve of the Master Meter and
switch off the dispenser.

Verification Procedure

Switch on the dispenser and also activate ATC if the Master Meter ATC is on.

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Set the display reading of both the dispenser and the Master Meter to zero.
Make a delivery of at least 1 minute after the maximum flow rate is achieved.
Record the display readings of both the dispenser and the Master Meter
Deactivate the dispenser and the Master Meter.
calculate Error by using the formula :

Repeat the process twice more

Gravimetric Method

Gravimetric test is done by using a weighing machine to determine the weight and then converting it into volume
via density. Density correction is necessary for conversion of weight into volume as required during
testing accuracy by Gravimetric Method.

Equipment needed
D i s advan t a g e s
A Certified Weighing Instrument to measure weight up to: (Sum of test
cylinder weight, weight of LPG extracted for testing) plus additional 10%
Density varies with Pressure and
thereof.
Temperature. So, maintenance of
The weighing instrument should have an e value of 0.1 (10% of 1%) or
constant temperature and pressure
better.
throughout the testing period is
One Standard Thermometer with ±0.2°C accuracy.
necessary.
One hydrometer pressure vessel with ±0.5 kg/m3 accuracy.
The result is not very accurate.
ASTM Table 53 (for density correction to 15°C
Gas disposal is a problem.
ASTM Table 54 (for volume reduction to 15°C)

Down load ASTM Table 53 | ASTM Table 54

The Method
If the dispenser allows the display of both compensated volume at 15°C (VFD15) and un-compensated volume (VFD) note
both indications and then switch off the compensation mode, if possible.
Place some oil or glycol in the thermo well of the dispenser and place the thermometer to record the temperature TFD.
Place the LPG cylinder on the weighing instrument and tare off the value or record the value for deduction.
Reset the dispenser to zero.
Make a delivery for at least 1 minute or a volume 2 X Vmin, whichever is greater.
Halfway to the delivery, record the temperature TFD
Complete the delivery and note VFD
Convert the mass (from the weighing instrument) to a volume at base condition, VREF by dividing the mass by D15

Example
The hydrometer shows a density of 0.505 kg/l, Temperature recorded is 25°C. Then using the table 53 the density of LPG at
15°C is 0.520 kg/l; obtained at the intersection of the column for observed density 0.505 and the row for temperature 25°C.

Determine the temperature conversion factor (CtFD) from Table 54 and calculate the converted dispenser volume.
VFDc = VFD X CtFD

Example

The temperature of LPG is 25°C, and the density of LPG at 15°C was calculated to be 0.520 kg/l, then from the
table 54 the volume conversion factor CtFD = 0.972; obtained at the intersection of the column for density
0.520 and the row for the observed temperature 25°C.

Check if VFD15 as shown in the Compensated Volume Indicator of the dispenser agrees with VFDc as calculated.
Calculate Error by using the formula:
Error = (converted dispenser volume VFDc - volume at base condition, VREF) / volume at base condition, VREF X
100
Repeat the process twice more

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