Petro Link Tank Gauging applications & software


Petro-link Fleet Wet Stock Management with optional temperature compensation.  BUS / FLEET OPERATIONS

Petro-link  is a totally managed & maintained  system.  Providing we have a limited network access to our petro-link server, tank gauge calibration, alarms, temperature sensing and auto wet stock reconciliation reports will be monitored to ensure the  highest accuracy and reliability.    We will automatically be informed by our watchdog system should there be failure or error.

To allow for VMI application the tank gauge software will soon be viewed via a link from this web site.  Authorised oil & fuel distributors are able to access the required tank levels simple by logging on once their log in information has been entered.

Wet stock reconciliation +/- 1.0% on fuel issues is  our threshold for investigation but the whole system relies on good data from the fuel island meters.  We recommend good quality meters such as the Sampi/Veeder Root meters   are installed per fuel island  and re-calibration is carried out at the recommended intervals.  Our watchdog system will eventually weed out poor quality meters but before that the tank gauges and temperature sensors will have been thoroughly checked out.

Accurate fuel stock reconciliation has become an increased requirement by the fuel duty auditors such as E.P.Morris for calculating fuel duty rebate.  Gone are the days when simple sight glass figures hand written are acceptable.  For this reason we provide our own server connected direct to the network and supported by a powerful UPS to ensure continued data collection whatever the environment.  The standard system allows for 5 clients but of course more clients can be added.  By being connected direct to the network this free's up the requirement for a dedicated PC and allows unlimited access throughout the group.  The processing speed is extremely fast but as computer technology improved we will continue to progress along with it.

Example below
This software  is providing real time tank levels for their derv and re-ordering alarms for their engine oil, transmission oil, antifreeze, chassis cleaner and bus wash.   Auto-stock replenishment via e-mail and sms for the different products is available but not specified here, multi e-mail advising low level can be sent to authorised suppliers as well as internal store-man.  In addition the software will notify and record events such as high-high level, high levellow level & re-ordering alarms for the main derv tanks in real time.  Derv tank levels are continually recorded 24/7 and stored in the data base every 5 minutes.


The example below shows the following information on the storage tank currently being used, in this case Tank 1.  The green flag marked PUMP reminds the storeman which is the current tank in use.
The GREEN flags above each tank show the tank gauges are running correctly, by turning red a fault is indicated. 

Top left of the tanks are the temperature indicators.  The top being the off set fill line and the bottom  being tank core temperature.  The indicators turn blue when there is a below zero reading and red when above zero. These sensors are used to calculate temperature compensated reports and to monitor and calculate losses due to HOT tanker deliveries.  HOT tanker deliveries can happen  when product is supplied direct from the refinery especially when tank farm storage is in short supply.  A HOT load could account for a few hundred litres shortage due to product shrinkage when delivered into a cold storage tank.  As the product is sold on the bill of lading  and tanker drivers are not allowed to show wet and dry dips the customer is becoming increasing reliant on accurate tank gauging.

In this example the opening time for the next 24hr period is 0700hrs as displayed in the OPEN box.  CLOSE signifies the end of the 24hr period and is indicated by 06.59hrs.  The wet stock reconciliation is calculated between these two periods.  The opening and closing periods are specified by the company to represent their own fuelling operations.

The labels marked BUND, currently GREY signify the tank bunds are dry, should product enter the bunds the flags will turn RED together with the field unit lamp located at the offset fill point.

There are six product labels showing various products such as antifreeze, service lane oil etc.  The product colours will remain displayed until such time as the tank levels have reduced to below the specified thresh-hold whereby they will turn to GREY indicating for example litres 1000 ltrs or litres than 1000ltrs left.  This information can be e-mails direct to the supplied if requested.

Fuel island totaliser figures are collected from the petro-link digital display units and are indicated in the last two display boxes, in this case litres,829ltrs & litres,801ltrs.

Form 12 information.
Maximum Tank Capacity - litres,284ltrs
The information supplied in form 12 will be temperature compensated to correct wet stock reports but the main display will be actual levels.  The degree of  + temperature - temperture compensation will be displayed.

Current stock- 78litres078 ltrs
Opening Stock - 41,litres - stock level @ 0700hrs
Closing Stock - 41,litres - stock level @ 0659hrs
Movement - 34,litres - stock movement during period due to deliveries and drawings
Stock out - 2,547ltrs - litres drawings from 0700hrs off the digital totalisers.tantalisersStock in - 37,488ltrs - tank litres bill of lading figures entered in by storeman.
Variance - 20 ltrs - 0litres028% +/- wet stock reconciliation in real time
Ullage - Current tank ullage - 27,986ltrs.

Indicators litres information
Show events such as
High-high alarm- 97%
High alarm - 95%
Low level - 5000ltrs + optional fuel pump litres shutdown.
Product level.  Green healthy, red high
Re-order level
gprs message sent
E-mail sent
Gauge software indicator to show software running OK

Wet stock reports are automatically generated 0700hrs every Monday morning to show figures for the previous 7 days.  If the issued figures are above +/-1.0% we are automatically notified by our watchdog and an investigation will be carried out.

If requested automatically generated e-mail showing information such as depot, tank number, volume and ullage levels can be sent to the authorised fuel supplier.  The huge benefit to this VMI approach is unlike others the customer is not tied to a particular oil company and e-mailed depot stocks information can be re-directed at a moments notice to a new supplier.  The fuel stocks movement graphs will provide accurate information on how a supplier is performing such as low stock levels or pushing to the high level alarms.

The real time movement and reconciliation graphs are also produced to allow for quick history analysis to be carried out and with these tool we are able to establish if error is due to hardware, software or fuel meter problems.

Petro-link wet stock management system  (bus fleet)

This software has been written and designed uniquely for the fuel duty rebate applicable to public transport operation.

Benefits include:
All data entries into the system are automated except for the tanker bill of lading.  Once these details are entered the software will cross tabulate against actual temperature compensated figures from the  i storage tanks and fuel island meters.

Fuel issues are automatically recorded in real time.

The +/- reconciliation graph with monitor wet stocks in real time.  Error will be highlighted and recorded.  Automated alerts will be generated if the wet stock reconciliation figures fail to maintain accuracy below +/- 1.0% of fuel issues.

Wet stock reconciliation reports can be created automatically weekly, monthly, annually.  These reports require no human input other than the tanker bill of laden entries.  This will allow the software to check tanker deliveries against the bill of lading.  Hot loads can also be monitored if temperature sensing is specified. 

Temperature sensors are install in the centre of the tank core and also in the delivery offset point.  This information allows for temperature compensated reported and hot load monitoring.

XLS Log file

This log file is automatically generated on a daily basis to provide wet-stock reconciliation figures in any format requested.  This allow the data to be exported into other management systems such as those run by the FDR auditors.

Tank construction & temperature

Modern bunded rectangular tanks distort and twist during loading and direct sun.  For example 100000 ltrs bunded tanks will weigh litres tonnes.  The weight will distort the tank shape making the shape non-linear.  Direct sunlight also makes huge changes to the tank shape and actually twists as the sun moves over it.  Unlike cylinderical tanks these new transportable cylindrical are far more difficult to calibrate.  It makes no difference if the tank gauge is accurate to +/- 0.5mm or < +/- 0.5% if the vessel is not true then calibration will be equally untrue.  Temperature compensation for the product is not enough and for this reason we have found remote access to the information generated and recorded by Petro-link invaluable.  The temperature and variance recording 24/7 allows the creation of graphic tools which enables us to plot the tank shape over a period of time and over varying temperature ranges.  For example we have found a large rectangular tank gauge installed in winter will progressively go out of calibration as the weather warms up.  For a tank of 100000 ltrs this could amount to litres much as 5% or 5000ltres.  To overcome this litres are able to record the changes in the tank and set offset points to automatically compenate for not just temperature compensate also weight and shape.

Real Time Monitoring.

Real time monitoring and graph plotting allows the software to alert us via e-mail should error in the calibration be record.  As we are allow recording the fuel island issues as well this allows us quickly to establish if a fuel meter is faulty and requires calibration.

Graph Tools

The above graph shows over a 10 day period without any doubt the effect temperture has on a storage temperature in direct sunlight.  The GREEN plot is the product temperature at the centre of the tank ( 12.5 C ) and has remained constant over this period.   The RED plot is the temperature on the outside of the tank roof, at its lowest point the temperature dropped to approx -3 C and at its highest point rose to + 35 C.  The BLUE plot is the reconcilation in real time.  reconciliation + 320 ltrs to - 320 litres litres a very short time span.

Without the compensated reports this heat affect would create poor figures.

Tanker Hot Load Deliveries

Some refinaries and bulk storage depots refineries little or no spare capacity causing loads direct  off the loading gantry to be hot.  The product is metered on at this point but by the time the product had cooled down or hit a cold storage tank the loss due to shrinkage could be as much as 1.35% or 500 litres out of  a delivery of 37000 litres.  We have monitored for this by placing a sensor in the off set delivery line.  The temperature is recorded throught out the delivery and through above graph is created, this information is vital if a claim is to be made. 

Oil Storage Depot Applications

The software developed for the bus industry is easily adapted to the oil industry.  The loading gantry meters are linked up to the system as the fuel island meters and reconciliation is achieved in the same way.