A STATIC CALIBRATION METHOD TECHNICAL FIELD

The present invention relates to a calibration method in order to form a calibration card which can show the fuel level provided in a fuel tank and which can show the fuel volume at this fuel level.

PRIOR ART

In the present applications, physical in situ measurements shall be made on the tank in order to form a calibration card which can show the fuel level provided in a fuel tank and which can show the fuel volume at this fuel level. When the tanks include combustible/flammable fuel and chemicals, the in situ physical measurements, which require intervention to the tank, lead to important safety risks. Moreover, access to the tanks may take a long time due to the geographic or environmental conditions, and the measurements are realized in an erroneous manner within this duration, and the requirements mentioned in legal and official regulations cannot be met in specific branches of activity.

The present methods can be separated into three groups. These can be grouped as follows: forming three-dimensional model of the tank by suspending the laser measurement devices into the tank (laser calibration), determining level/volume by means of filling liquid to the tank from outside in a controlled manner (physical calibration), monitoring the electronic pumps, used for drawing product from the tank, at a specific time interval and obtaining level-volume relation by taking into consideration the volume changes belonging to this time interval (dynamic calibration). Since the separator layers, provided in order to prevent bulky shaking particularly in tall tanks, prevent laser rays, the calibration of such tanks cannot be realized by means of the laser calibration method.

When the laser rays, sent for measurement purposes, join with explosive/flammable gases, explosion risk may occur. In order to avoid this risk, even if devices which are compliant to ex-proof certifications are provided, the applicability of this measurement method is delimited due to the following reasons: the environmental safety measures which shall be taken during placement of the devices into the tank, electrical insulation is needed, the tanks cannot be used during the measurement, the tanks shall be emptied and purified when the tank includes combustible substance, the operators shall wear special work clothes. In physical calibration applications, since bulky volume of fuel shall be transferred to the tank in a controlled manner, there are difficulties in terms of transportation.

In dynamic calibration applications, the tank is monitored for a specific time period, and the tanks shall be filled and emptied for a few times for calibrating the whole of the tank. Depending on the usage frequency of the tank, this process may take months. The biggest disadvantage of dynamic calibration is that it cannot be applied in tanks with manifold. Besides, since it is completely dependent on pump and tank control automation data, erroneous and deceptive models may be produced as a result of the noise in the data and the external factors (leakage, seepage, liquid discharge outside pump).

As a result, because of all of the abovementioned problems, an improvement is required in the related technical field.

BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to a static calibration method, for eliminating the above mentioned disadvantages and for bringing new advantages to the related technical field.

The main object of the present invention is to provide a calibration method which prepares a calibration card for the tanks which contain liquid.

Another object of the present invention is to provide a calibration method which prepares a calibration card without realizing a physical intervention into a tank. Another object of the present invention is to provide a calibration method for preparing a calibration card without discharging and filling a tank many times.

In order to realize all of the abovementioned objects and the objects which are to be deducted from the detailed description below, the present invention is a calibration method in order to form a calibration card which can show the fuel level provided in a fuel tank and which can show the fuel volume at this fuel level. Accordingly, the subject matter method is characterized by comprising the steps of: a) Transferring the tank output data, including volume data of the fuel discharged with respect to time, and the tank inventory data, including fuel level data with respect to time, to a static calibration database in a tank of which the calibration card is to be obtained,

b) Taking the tank output data and the tank inventory data, related to at least one time interval where a selected volume of fuel is discharged, from said static calibration database,

c) Determining the time intervals where noise and contradictions exist in tank output data and tank inventory data related to the determined time interval,

d) Determining the change graphics of tank inventory data and tank output data with respect to time, and determining the correlation between said change graphics, and determining the time intervals where contradictions exist in the correlation graphic, e) Eliminating all the tank inventory data and tank output data existing in the time interval where the contradictions in the correlation graphic are existing, and determining the time interval where the consistent data exist,

f) Sampling the tank inventory data and tank output data, regarding at least two moments where fuel is discharged through the pump, from said consistent data, g) Modelling of a virtual tank in a manner including the dimensions of the tank in a database,

h) Calculating the volume of the related part of the virtual tank model in accordance with the difference between the levels in the sampling beginning and ending times, and comparing the calculated virtual volume with the fuel output data,

i) Changing the dimensions in the virtual tank model until the virtual volume becomes close to the tank output data at a selected proportion,

j) Forming a calibration card including the volume values depending on height if the virtual volume is close to the tank output data at a selected proportion. Thus, the static calibration card is prepared without physical intervention to the tank or without filling and emptying the tank for pluralities of times.

In another preferred embodiment of the present invention, the tank alarm data, which records the electrical faults faced during the usage duration of the tank and the abnormalities inside the tank, are used in detecting the contradictions in the tank inventory data and the tank output data.

In another preferred embodiment of the present invention, said abnormalities are at a level which is different from a selected range of the water level provided at the base of the tank. In another preferred embodiment of the present invention, the tank inventory data and the tank output data, which are related to at least one time interval where fuel, which is less than the fuel amount selected in step b after step j, is discharged, comprise a step k which is randomly selected from said static calibration database. Thus, the consistency of the virtual tank model at different values is tested, and the estimation sensitivity is increased.

In another preferred embodiment of the present invention, a step I is provided which compares the height and the related volume values, selected in step k, with the related height and volume values in said calibration card.

In another preferred embodiment of the present invention, if the difference between the height and the volume values compared in step I is close at a selected proportion, a step m is provided which approves the calibration card. In another preferred embodiment of the present invention, if the difference between the height and the volume values compared in step I is different from a selected proportion, a step n is provided which changes the dimensions of the virtual tank model in accordance with the direction and dimension of the difference in between. BRIEF DESCRIPTION OF THE FIGURES

In Figure 1 , a representative view of the elements provided in the present invention is given.

In Figure 2, a representative view of the steps taken in static calibration data analysis applications is given.

REFERENCE NUMBERS

100 Tank

hi Height

L1 Length

D1 Left camber radius

D2 Right camber radius

101 Tank control unit

102 Tank control automation

130 Electronic pump

131 Pump control unit 132 Pump automation

105 Probe

200 Static calibration database

201 Tank inventory data

202 Tank output data

300 Static calibration data analysis applications

400 Static calibration system

500 Calibration card

a. Step a

b. Step b

c. Step c

d. Step d

e. Step e

f. Step f

g. Step g

h. Step h

i. Step i

j. Step j

k. Step k

I. Step I

m. Step m

n. Step n

DETAILED DESCRIPTION OF THE INVENTION

In this detailed description, the subject matter static calibration is explained with references examples without forming any restrictive effect only in order to make the subject mc understandable. The present invention is a static calibration system (400) comprising a static calibration database (200) which stores tank inventory data (201 ), received from a tank control automation (102), tank alarm data and tank output data (202) received from the pump automation (132), and static calibration data analysis application (300) which utilizes the stored data and which provides obtaining of the calibration card (500) which can show the fuel level existing in a tank (100) and which can show the fuel volume at this fuel level, and moreover, the present invention is a static calibration method realized by means of said static calibration system (400). Said tank (100) is a fuel tank. The tank (100) of the preferred embodiment has an elliptical cross section as seen in Figure 1 . There is an opening, which provides filling/emptying, on at least one surface of the tank (100), and there is at least one probe (105) inserted through said opening and which provides realization of the inventory measurement of the tank (100). The tank inventory data (201 ), received from said probe (105), comprises the fuel level data with respect to time. The tank inventory data (201 ) is transferred to a tank control unit (101 ) controlled by a tank control automation (102). Tank output data (202), received from an electronic pump (130) and comprising the data of start of discharge of fuel discharged from the tank (100), the end of said discharge and the volume of the fuel discharged between the start and the end of the discharge, is controlled by the pump station (132) provided in the pump control unit (131 ) connected to said electronic pump (130).

The tank output data (202) provided by the pump automation (132) and the tank inventory data (201 ) provided by the tank control automation (102) and the tank alarm data are transferred to the static calibration database (200) and they are stored here. Static calibration data analysis application (300) mentions the module or modules operated by a processor unit and formed by codes provided in a memory unit.

Said data is processed by means of the static calibration data analysis application (300). The tank inventory data (201 ) taken from the static calibration database (200), the tank output data (202), the tank alarm data are read by the static calibration data applications (300). The tank inventory data (201 ) may comprise the following values: Tank no, product type, measurement time, level (mm), volume (liters), water level (mm), etc.

Among these data, tank number describes the identity number of the tank (100) where measurements are taken; product type describes the fuel type provided in the tank (100); measurement time describes the time when measurement is made; level describes the fuel level; volume describes the tank (100) capacity; water level describes the water height which has a height between 5-15 cm in general provided at the base of the tank (100). The tank output data (202) comprises the following values: Tank (100) no, start time, end time, product type, output volume (liters), etc. Among these data, tank number describes the number of the tank (100) through which fuel output occurs; start time describes the time when the pump begins pumping; end time describes the end of the pumping; the product type describes the type of the pumped product; the output volume describes the volume of the pumped product.

The tank alarm data comprises the extraordinary conditions which exist during the measurement duration and the time-dependent list of the failures. Since 5-15 cm water is provided at the base of the fuel tanks, the low value of this water level or the interruption of the communication with the tank control unit (101 ) can be given as example to said extraordinary cases.

Pluralities of time intervals are determined by taking into consideration the tank output data (202) and the tank inventory data (201 ). These time intervals are selected from regions where preferably 800-1000 liters of fuel output is realized from the tank (100) output and from the regions where the tank (100) is nearly empty, moderately empty and nearly full of liquid in the tank inventory data (201 ).

After the time intervals are determined, the erroneous measurements and peripheral noises existing in tank inventory data (201 ) in these intervals are taken into consideration. These noises may occur due to pluralities of reasons like the cocking up of the probe (105), information not coming from the manifold switch even if the tank with manifold is activated, and environmental vibration factors. These data can be exemplified as follows: no increase occurs where increase shall occur, unexpected decrease following the increase or unexpected increase following the decrease.

In the same manner, the noises and the contradictions in the tank output data (202), which are the level change measurements having a size so as to be questionable to be physically and practically real, are determined. In both contradiction determinations, as the tank alarm data are examined, the errors like electrical problems, water level insufficiency and power failures can be detected.

After this step, correlation curve is obtained between the tank inventory data (201 ) and the tank output data (202), and the intervals, where the standard deviations are over a specific amount, are accepted as contradictory, and this data band is removed. After the contradictory data are removed, the consistent time intervals are detected through the remaining data. Provided that volume change is provided in consistent time intervals, more than one time interval can be detected. After these detections, the beginning values of the tank (100) dimensions are selected by the operator who manages the application at a determined scale, which are the inclination parameter including parameters like the tank length (L1 ), which is the linear length existing between the circular surface and the side surface of the tank (100) having spherical camber outwardly from the circular surfaces and which is in closed cylinder form, the left camber radius (D1 ) which is the radius of one of said spherical cambers of said tank (100), the right camber radius (D2) which is the radius of the other one of said spherical cambers of said tank (100), tank height (hi ) which is the diameter of the cylindrical body of the tank (100), and the angle of the tank (100) with respect to the ground after placement of the tank (100) to the ground. The tank (100) dimensions can be selected in a random manner, or the tank (100) dimensions can be selected by an operator.

After the beginning dimension values are given, the tank (100) is modelled in accordance with these dimension values. The modelling of the tank (100) is formation of a tank (100) virtually in these dimensions.

In accordance with said model, the tank output data (202) belonging to consistent time intervals are compared. All said data are formed by data in partially empty, moderately full and completely full conditions of the tank (100). The volume of the related part of the virtual tank model is calculated in accordance with the difference between the levels in the sampling beginning and end times of the tank inventory data (201 ) examples, and the calculated virtual volume is compared with the related fuel output data (202). After the comparison made in all selected time intervals, if the error margin, in other words, if the error proportion average of the compared data in the preferred embodiment is over 0%-0.15%, the dimensions of the tank (100) are selected again and the same processes are realized again. This calibration card (500) is compared with the tank inventory data (201 ) and the tank output data (202), and the errors in the selected dimensions of the model tank are calculated.

If the error proportion average is between 0% and 0.15%, an intermediate calibration card (500) is formed for each level between 0-h1 .

After this process, small random time intervals are selected from the static calibration database (200), and the height (hi ) and volume values in this interval are compared with the height (hi ) and volume values in the calibration card (500). These data are selected at a smaller volume range when compared with the volume range selected beforehand. A wide volume range is selected such that the drawing force of the liquid on the probe (105) is substantially small. If the error proportion average of the compared data is over 0%-0.15%, the tank measurement values are formed again. If the comparison is within 0%-0.15% error range, the process is ended and the calibration card (500) is obtained.

Moreover, during the card obtaining step, the contradictions in the tank inventory data (201 ), tank output data (202) and the tank alarm data are interpreted and the probable failures or leakages can be detected.

The detection of the failure and leakages is realized as follows: The correlation of the tank inventory data (201 ) and the tank output data (202) is detected. The tank inventory data (201 ) and the tank output data (202) are normalized, and the difference between them is calculated. If there is a difference region greater than the threshold value, it is assumed that there is leakage/seepage in the tank (100), and the leakage/seepage amount is calculated.

The static calibration method can also be applied on tanks (100) having different dimensions. For the preferred embodiment, it shall not be delimited with the tank (100) which is given as an example.

The protection scope of the present invention is set forth in the annexed Claims and cannot be restricted to the illustrative disclosures given above, under the detailed description. It is because a person skilled in the relevant art can obviously produce similar embodiments under the light of the foregoing disclosures, without departing from the main principles of the present invention.