FORM 2

THE PATENTS ACT  1970
(39 of 1970)
&
THE PATENTS RULES  2003

COMPLETE SPECIFICATION
(See section 10  rule 13)

“A method for estimating fuel volume in a tanker positioned at cellular site of a telecommunication system”

Tejas Networks Limited
2nd floor  GNR Tech Park  46/4  Garbebhavi Palya 
Kudlu Gate  Hosur main road 
Bangalore 560 068  Karnataka  India

The following specification particularly describes the invention and the manner in which it is to be performed.

TECHNICAL FIELD
The present disclosure is in relation to Telecommunication Power Systems [TPS]. More particularly  it relates to a methodology involved in estimating liquid volume in a tanker positioned at a cellular site of Telecommunication Switching System [TSS].

BACKGOUND
The reliability of telecommunication systems that users have come to expect and depend on is based  in part  on the systems"" reliance on redundant equipment and power supplies. Telecommunication switching systems  for example  route tens of thousands of calls per second. The failure of such systems  due to  for instance  the loss of incoming AC power  may result in a loss of millions of telephone calls and a corresponding loss of revenue.

Traditionally  the AC power from a commercial utility has been used as a primary source of electrical power. Telecommunications power systems have included backup power arrangements which attempt to ensure continued power in the event of black-outs and other disturbances in the commercial power grid. To accomplish this  a diesel generator (DG) is often used as a backup power source and is backed up by an array of lead acid batteries and like  for example valve-regulated lead-acid (VRLA) batteries. The DG set will be used to charge the VRLA batteries as well as power the load. When the VRLA battery is fully charged  the DG is shut-off and the load is made to run on the VRLA batteries. This set up is currently used in the off-grid solution i.e. when the set up is able to operate without any grid connectivity.

In many parts of developing world  the AC power from the commercial utility is unreliable. In these parts of the world  it is not uncommon to see AC power being available for less than 6 hours in a day. Thus  in these areas  DG power is replacing the commercial utility as the primary source of power.

Diesel Generators consume large amounts of diesel. Also  the access to these cellular sites in developing countries is very poor. Consequently  large quantities of diesel need to be stored within the cellular site to avoid repeated visits to the cell site to replenish the used fuel. Typically  the cellular sites house a Diesel tank that stores around 250 litres of diesel.

Diesel is precious resource and easily tradable commodity in the developing countries. The quantity of diesel stored is valued significantly monetarily. Due to lack of sophisticated law and order  diesel is being stolen frequently in these areas causing significant monetary loss to cellular site operators.

Secondly  cellular site operators face stiff penalty from the telecom service providers (telecom service providers house their equipments such as BTS  backhaul equipment in the cellular site. The cellular towers are expected to provide reliable power to the BTS/backhaul equipment) whenever the power to the cell site is lost. Since diesel is the primary source of power in these areas  knowing the amount of fuel left in the tank is helpful to avoid penalties.

Thirdly  the amount of diesel consumed by a diesel generator is directly related to the wear and tear on the equipment. Knowing precise rate of fuel consumption is therefore helpful to trigger periodic preventive maintenance procedures that will prolong the life of the equipment.

Increasingly cellular site operators are installing diesel monitoring solution to solve the three problems mentioned above. Typically  a depth sensor is placed at the mouth of the fuel tank (sometimes the sensor comes integrated with the fuel tank cap). The sensor is responsible for monitoring the fuel level. This is translated to the volume of fuel left in the tank using mathematical formulae.

The main issue is that there is no agreed standard on the design of a fuel tank. Every Diesel Generator manufacturer has a proprietary tank shape and tank capacity. Consequently  during the time of installation  the fuel tank needs to be measured accurately and the correlation between the fuel level and the volume needs to be derived. While  this is a simple exercise in the case of cuboidal tanks  the computation is non-trivial in the case of spherical/cylindrical and other tank shapes. Also  simple mathematical computations cannot address inherent fuel-tank manufacturing abnormalities  which may cause significant deviations from the computed values.

A site technician visiting the cell site is not qualified to carry out such computations and in many instances  the company’s manufacturing the fuel level sensors spend several months/years of effort to characterize the precise correlation between the fuel level and the volume of fuel left in the tank. Each time a diesel manufacturer decides a novel tank shape  this characterization effort needs to be repeated.

Therefore  there is a need for a single unified characterization procedure that will be independent of the tank type and would not require months of calibration effort. The characterization procedure should be simple enough and economical so as to be carried out by a cellular site technician.

OBJECTIVES
First objective of the present disclosure is to provide a method for estimating the liquid volume in a tanker positioned at cellular site of a telecommunication system.
Second objective of the present disclosure is to provide a simple  non-tedious  reproducible  economical and efficient methodology for estimating the liquid volume in a tanker.

SUMMARY OF THE DISCLOSURE

Accordingly  the present disclosure is in relation to a method for estimating liquid volume in a tanker positioned at cellular site of a telecommunication system  comprising steps of installing sensor at suitable position of the tanker; adding known volume of liquid to the tanker; and measuring depth of the tanker followed by generating approximation by interpolation to obtain the volume of the liquid.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The features of the present disclosure will become more fully apparent from the following description and appended claims  taken in conjunction with the accompanying drawings  tables and graphs. Understanding that these drawings depict only several embodiments in accordance with the disclosure and are  therefore  not to be considered limiting of its scope  the disclosure will be described with additional specificity and detail through use of the accompanying drawings.
Figure 1 is a flow chart of a conventional method towards estimating the liquid volume in a tanker.
Figure 2 is a flow chart of a method of instant disclosure towards estimating the liquid volume in a tanker according to one embodiment of the present invention.
Figure 3: example illustration of a spherical tank with a capacitive fuel sensor rod bolted to the fuel tank cap according to one embodiment of the present invention.

Figure 4: Graph depicting comparison between the actual volume and the approximation tool based volume according to one embodiment of the present invention.

DETAILED DESCRIPTION

Before explaining any one embodiment of the present disclosure by way of drawings  experimentation  results  and pertinent procedures  it is to be understood that the disclosure is not limited in its application to the details as explained in below embodiments set forth in the following description or illustrated in the drawings  experimentation and/or results. The disclosure is further capable of other embodiments which can be practiced or carried out in various ways. As such  the language used herein is intended to be given the broadest possible scope and meaning; and the embodiments are meant to be exemplary--not exhaustive. Also  it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.

The present disclosure has been made in view of the above problems  recited under background. Therefore  the purpose of the present disclosure is to provide a simple  economic  efficient and reproducible method for estimating the volume of a liquid in a tanker.

The words liquid  fuels including diesel  petrol  kerosene  alcohol or combinations of the liquid fuel are used synonymously in the entire specification. Similarly  the term ‘liquid level’ refers to the level of fuels including diesel  petrol  kerosene  alcohol or combinations thereof.

The present disclosure is in relation to A method for estimating fuel volume in a tanker positioned at cellular site of a telecommunication system  the method comprising installing a fuel level sensor for being mounted on a tank  the fuel level sensor represents the distance between the sensor and the surface of the fuel in the tank  generating a table by adding known quantities of fuel into the tank in order to estimate the differential amounts of fuel dispensed into the tank per unit of associated differential height change  feeding the generated table values  the change of fuel level value and the corresponding change in fuel volume  in the fuel level sensor and estimating the volume of the fuel in the tanker by characterizing the relationship between the fuel level value and the fuel volume entered in the fuel level sensor  wherein the fuel level sensor use spline polynomial to calculate the amount of fuel left in the tank.

In an illustrative embodiment the tanker shape includes but not limiting to triangle  circular  cylinder  square and rectangular.

In an experimental embodiment  the sensor is bolted inside the cap of the tank.

In an experimental embodiment  the step of generating a table by adding known quantities of fuel into the tank is preceded by a step of emptying the previous liquid contents  if any.

In an experimental embodiment  the depth is measured multiple times with known fuel volume.

In an experimental embodiment  the measurements are noted as indicated by the fuel level sensor.

In an experimental embodiment  the approximation is performed by several methods including but not limiting to spline interpolation methodology.

In an experimental embodiment  in a 400L tank  the fuel level sensor reading may be obtained when the total quantity of fuel in the tank is 0L  25L  50L  ...375L  400L.

In another experimental embodiment  the fuel level sensor reading may be obtained when the total quality of the fuel in the tank is 0L  50L  100L  ...350L  400L.

In an experimental embodiment  the said method of estimating liquid/fuel volume can be applied to water storage systems  water treatment plants  water distribution tanks and in non-standard brewery industries.

In the approach of instant disclosure  a standard procedure is developed that can be carried out by a simple technician. Instead of estimating the volume accurately  our method resorts to a spline approximation of the DG tank  which is good enough for the proposed application. A site technician with no knowledge of advanced mathematics will be able to carry out the procedure.

In summary  to overcome the limitations of the conventional approach  the present disclosure employs a simple  reproducible  economical and efficient methodology to arrive at the volume of the tank. It follows with a step wherein a site technician measures the depth of the liquid or fuel in the liquid or fuel tank after a known volume is put in. This particular step is repeated multiple times to get accurate results. The resulting data is handled by the site software which creates a spline approximation of the tank volume. This can be used to obtain the volume of fuel in the tank. Figure 2  provides flow chart  which provides a comparison of figure 1 (conventional approach) for quick understanding of the reader.

Hereinafter  a method for estimating liquid volume in a tanker positioned at a cellular site of a telecommunication system  in accordance with the present disclosure will be described in more detail with reference to the following examples. These examples are provided only for illustrating the present disclosure and should not be construed as limiting the scope and spirit of the present disclosure.

Additionally  the disclosure is further illustrated by the following examples  which are not to be construed in any way as imposing limitations upon the scope of the present invention. On the contrary  it is to be clearly understood that various other embodiments  modifications  and equivalents thereof  after reading the description herein in conjunction with the drawings and appended claims  may suggest themselves to those skilled in the art without departing from the spirit and scope of the presently disclosed and claimed invention.

Example 1: Illustration using a spherical tank
Figure: 3 provide an illustration using a spherical fuel tank with a capacitive fuel sensor rod bolted to the fuel tank cap. The total volume of a spherical tank with radius R is well known to be This would represent the amount of fuel in the tank when the tank is filled to the brim. However  as the diesel generator consumes fuel  the fuel level drops and the volume of fuel in the tank decreases. To precisely know the amount of fuel left in the tank  the correlation between fuel level and the fuel volume needs to be calculated. The calculation of the amount of fuel left in the tank when the fuel level is ‘h’ is non-obvious and involves advanced calculus. It can be shown that when the fuel level in the tank is ‘h’  the amount of fuel left in the tank is .
The objective of this example is to demonstrate that the exact characterization of the relationship between fuel level and the fuel volume is highly complicated. Note that the above calculation assumes a perfectly spherical surface with no manufacturing aberrations. With manufacturing irregularities  this approach is beyond calculus and would require a sophisticated computer to calculate the volume via finite element methods. Such approaches are beyond the capabilities of a site technician. Consequently  the characterization needs to be carried out in a manner that is friendly to the site technician.

Example: 2 Filling the tank with known volumes of fuel to determine the depth
The site technician is required to fill the tank with known volume of the liquid followed by noting the values as indicated in the liquid level sensor. Before this step  the site technician may need to empty the contents of the tank  if any. A step of removing previous liquid contents needs to be performed by the site technician before proceeding with the measurement of the depth. Below is an is an example table generated by the technician  by filling the tank with known quantities of fuel and noting down the values indicated by the fuel level sensor.
Table 1: Fuel volume in the tank and fuel level sensor reading
Fuel Volume in the tank
(Percentage of the total volume) Fuel Level Sensor Reading
(Percentage of the total fuel tank depth)
0% 100%
12.5% 81%
25% 65%
37.5% 50%
50% 37%
62.5% 25%
75% 14%
87.5% 6%
100% 0%

Figure 4 is a graph that plots the values of the fuel volume as a function of the fuel level as indicated by the approximation tool. It also plots the actual fuel volume as a function of the fuel level (based on the exact formula given above). In this example  these two values match perfectly indicating high level of confidence in the approximation tool.

Example: 3 Estimating the liquid volume

The relationship between the fuel-level (as indicated by the fuel level sensor) and the fuel volume can be characterized by the mathematical function. i.e.  if ‘V’ denotes the fuel volume and ‘h’ denotes fuel sensor reading then    denotes the mathematical function that takes in fuel sensor reading ‘h’ as the input and provides the Volume ‘V’ as an output.

The site technician first installs the fuel level sensor and then empties the tank. Known quantities of liquid are added to the tank and the liquid level sensor reading is noted. This experiment can be repeated for better accuracy. Those skilled in the art would realize that the number of readings required depends on the shape of the tank as well as the accuracy required. The more exotic the tank shape  more readings need to be obtained. Then  the technicians table consisting of (fuel-sensor reading  fuel volume) can be thought of as the relationship ‘F ‘for very specific values of ‘h’.

In mathematics  there is a well-known theorem called ‘Taylor-series’ theorem. According to this theorem  it is possible to approximate a wide range of functions (technically speaking  the functions need to be infinitely differentiable) as polynomials (polynomials are functions of type a+bx2+cx3....). The approximation can be made arbitrarily close to the original function by choosing a higher degree polynomial.

Such a polynomial is called spline and the approximation methodology is called spline interpolation.

For those skilled in the art  it should be clear that the method does not restrict itself to spline interpolation and in fact can be applied regardless of the type of interpolation technique used. The current embodiment uses a spline interpolation only as an example. There are well defined mathematical techniques present in the literature to construct such a spline using the data provided by the site technician. Once these subroutines are embedded into the fuel sensor  the fuel sensor can construct the spline. Now  the fuel sensor is said to be characterized. The fuel sensor can use the spline polynomial to calculate the amount of fuel left.

Example: 4 Applications of the instant disclosure in other technological areas

The methodology as disclosed in the present disclosure can be applicable to other technological areas including but not limiting to the water treatment plants  water storage tanks  water distribution tanks and in some non-standard brewery industries.

While various aspects and embodiments have been disclosed herein  other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting  with the true scope and spirit being indicated by the following claims.

We claim:

1. A method for estimating fuel volume in a tanker positioned at cellular site of a telecommunication system  the method comprising:
installing a fuel level sensor for being mounted on a tank  the fuel level sensor represents the distance between the sensor and the surface of the fuel in the tank;
generating a table by adding known quantities of fuel into the tank in order to estimate the differential amounts of fuel dispensed into the tank per unit of associated differential height change;
feeding the generated table values  the change of fuel level value and the corresponding change in fuel volume  in the fuel level sensor; and
estimating the volume of the fuel in the tanker by characterizing the relationship between the fuel level value and the fuel volume entered in the fuel level sensor  wherein the fuel level sensor use spline polynomial to calculate the amount of fuel left in the tank.

2. The method as claimed in claim 1  wherein the tanker shape includes but not limiting to triangle  circular  cylinder  square  rectangular including 2-dimensional and 3-dimensional shapes.

3. The method as claimed in claim 1  wherein the sensor is bolted inside the cap of the tank.

4. The method as claimed in clam 1  wherein the step of generating a table by adding known quantities of fuel into the tank is preceded by a step of emptying the previous liquid contents  if any.

5. The method as claimed in claim 1  wherein the depth is measured multiple times with known fuel volume.

6. The method as claimed in claim 1  wherein the measurements are noted as indicated by the fuel level sensor.

7. The method as claimed in claim 1  wherein the approximation is performed by several methods including but not limiting to spline interpolation methodology.

8. The method as claimed in claim 1  wherein the method of estimating fuel volume can be applied to water storage systems  water treatment plants  water distribution tanks and in non-standard brewery industries.

Dated this the 20th day of February  2012

ABSTRACT

A method for estimating fuel volume in a tanker positioned at cellular site of a telecommunication system

The present disclosure is successful in providing a simple  reproducible  economical and efficient methodology for estimating liquid volume in a tanker. More particularly  it helps in overcoming the limitations of the prior art involved in estimating the fuel volume in a tanker positioned at cellular site of a Telecommunication Power Systems [TPS].