DESC:FORM 2

THE PATENTS ACT, 1970

(39 of 1970)

&

THE PATENT RULES, 2003

COMPLETE SPECIFICATION

[See Section 10 and Rule 13]

TITLE:

“A METHOD OF DETECTING LEAK IN A TANK OF A VOLATILE LIQUID”

APPLICANT:

PADMINI VNA MECHATRONICS LTD
A company incorporated under the Indian Companies Act, 1956
having address at
Plot No. 100-101, Sector 35, Phase VII, Udyog Vihar, Gurgaon-122001, Haryana, India

PREAMBLE TO THE DESCRIPTION:
The following specification particularly describes the invention and the manner in which it is to be performed:

FIELD OF THE INVENTION
The present invention generally relates to the field of leak detection. More particularly, the present invention relates to a method of detecting leak in a tank of a volatile liquid, which enables leakage measurement to be made with a nearly empty tank as well and which is less expensive and requires less extensive calibration.

BACKGROUND OF THE INVENTION
Leak detection of tank is implemented to alert the operator about a suspected release from any part of a storage tank system, which enables to prevent from soil contamination and loss of product. Many volatile liquids, such as hydrocarbons are stored in tanks. The vapors of such fluids are dangerous for global warming and emissions, and consequently it is necessary to be able to test that the tanks and accessories such as valve, solenoid valve, pipe, filling caps, vent caps and alike are not causing any leakages.
One of the common methods used is to use a pump to develop overpressure or under pressure inside the tank, and then to check the rate of change of pressure. In the case of a leak, the pressure changes more rapidly than in the case of no leakage. Many different methods are also used, wherein the energy taken by the pump is compared to a reference energy required by the pump when pumping through a known and calibrated orifice. However, all these methods are expensive and require extensive calibration.
US6886389B1, discloses about systems and methods for detecting and locating leaks in internal pressure vessels. A method generally includes forming a pressurizing cavity external to and adjacent an internal pressure vessel. A pressurized fluid is injected into the pressurizing cavity to cause pressurized fluid to flow from the pressurizing cavity through a leak into the internal pressure vessel. The internal pressure vessel is monitored to detect leakage of pressurized fluid into the internal pressure vessel. The main drawback of this invention is the use of pressurizing cavity as it has been known that uncontrolled internal or mold cavity pressure can cause serious damage to both plastic parts and metal molds of the system.
US8381577B2, discloses about a leak-testing method for a test container comprises measuring background noise within a chamber at atmospheric pressure with a trace sensor of volatile organic compounds that exhibit a measurement sensitivity less than or on the order of 1 ppb. Pollution is removed from an internal atmosphere of the chamber when the measurement of the background noise is greater than a predetermined threshold. The internal atmosphere of the chamber is mixed to homogenize a composition of the internal atmosphere receiving a container that defines a bounded internal space within which a volatile organic compound is present. A concentration of volatile organic compounds is measured within the atmospheric pressure chamber with the trace sensor of the volatile organic compounds. The measurement of the background noise is compared to the measurement of the concentration of the volatile organic compounds to detect the leak in the test container. The main disadvantage of this invention is that it uses a trace sensor to detect the volatile organic compounds as the trace sensors provide poor stability and greater environmental impact. Therefore, it fails to provide accuracy in places where accurate measurement is required.
Therefore, due to aforementioned drawbacks, there is a need to provide a method of detecting leak in a tank of a volatile liquid, which enables leakage measurement to be made with a nearly empty tank as well and which is less expensive and requires less extensive calibration.

OBJECT OF THE INVENTION
The main object of the present invention is to provide a stable method of detecting leak in a tank of a volatile liquid which provides accurate measurement.
Another object of the present invention is to provide a cost-effective method for detecting leak in a tank of a volatile liquid.
Yet another object of the present invention is to provide a method of detecting leak in a tank of a volatile liquid which requires less extensive calibration.
Yet another object of the present invention is to provide a method of detecting leak in a tank of a volatile liquid which enables leakage measurement to be made even with a nearly empty tank.
Still another object of the present invention is to provide a method of detecting leak in a tank of a volatile liquid by installing a vertical tower inside the tank.

SUMMARY OF THE INVENTION
The present invention relates to a method of detecting leak in a tank of a volatile liquid, which enables leakage measurement to be made with a nearly empty tank as well and which is less expensive and requires less extensive calibration.
In an embodiment, the present invention provides a method of detecting leak in a tank of a volatile liquid comprising steps of installing a vertical tower having a sealed volume A inside said tank, wherein the volume B of said tank is much larger than volume A of said vertical tower, volume A of said vertical tower allows fluid to enter from the lower part of the tower wherein the top of said vertical tower is close to the top of said tank, thereby enabling leakage measurement to be made when said tank is completely empty by completely immersing said vertical tower at the bottom close to bottom of said tank, installing at least two pressure sensors PS1 and PS2, wherein said pressure sensor PS1 shows the vapour pressure in larger volume B of said tank, sealing volume A of said vertical tower, which allows said pressure sensor PS2 to show a leak proof value of vapour pressure wherein the difference of the two pressure readings read through said pressure sensors PS1 and PS2 gives the indication of the leakage when there is any leakage in the larger volume B of said tank and since fluid inside the tank is at the same temperature for volume A and B so there should be minor difference between the two pressure values. A solenoid valve is installed at said vertical tower, which is normally closed at the top of volume A of said vertical tower, switching on said solenoid valve to connect Volume A of said vertical tower to volume B of said tank before making a comparative measurement, thereby allowing the pressures in volume A and B to equalize, comparing the pressure values of said pressure sensors PS1 and PS2 after a fixed duration of time, allowing to avoid a wrong reading, for instance the pressure of volume A of said vertical tower result in incorrect value due to liquid compression after refueling, or driving over bumps or by using a differential pressure sensor to show the difference of pressure between volume A of said vertical tower and volume B of said tank or by installing a switching valve exposed to a single pressure sensor initially to the volume A of said vertical tower, followed by volume B, or vice versa and said switching valve is a single three way valve and or as per convenience it is a two way valves.
The present invention provides a method of detecting leak in a tank of a volatile liquid, which enables leakage measurement to be made with a nearly empty tank as well and which is less expensive and requires less extensive calibration.
The above objects and advantages of the present invention will become apparent from the hereinafter set forth brief description of the drawings, detailed description of the invention, and claims appended herewith.
BRIEF DESCRIPTION OF THE DRAWINGS
An understanding of the method of detecting leak in a tank of a volatile liquid of the present invention may be obtained by reference to the following drawings:
Figure 1 shows a vertical tower attached to the tank bottom according to an embodiment of the present invention.
Figure 2 shows a vertical tower attached to the tank top along with filing cap according to an embodiment of the present invention.
Figure 3 shows a bulge in the tank top with the vertical tower in the tank according to an embodiment of the present invention.
Figure 4 shows pressure sensors PS1 and PS2 fitted in the tank according to an embodiment of the present invention.
Figure 5 shows an addition of a solenoid valve in the tank according to an embodiment of the present invention.
Figure 6 shows a differential pressure sensor version instead of two pressure sensors in the tank according to an embodiment of the present invention.
Figure 7 shows a version where a switching valve is used to expose a single pressure sensor first to the volume A in the tank according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION
The present invention will now be described hereinafter with reference to the accompanying drawings in which a preferred embodiment of the invention is shown. This invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiment set forth herein. Rather, the embodiment is provided so that this disclosure will be thorough, and will fully convey the scope of the invention to those skilled in the art.
Many aspects of the invention can be better understood with references made to the drawings below. The components in the drawings are not necessarily drawn to scale. Instead, emphasis is placed upon clearly illustrating the components of the present invention. Moreover, like reference numerals designate corresponding parts through the several views in the drawings. Before explaining at least one embodiment of the invention, it is to be understood that the embodiments of the invention are not limited in their application to the details of construction and to the arrangement of the components set forth in the following description or illustrated in the drawings. The embodiments of the invention are capable of being practiced and carried out in various ways. In addition, the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
The present invention provides a method of detecting leak in a tank of a volatile liquid, which enables leakage measurement to be made with a nearly empty tank as well and which is less expensive and requires less extensive calibration.
In an embodiment, the present invention provides a method of detecting leak in a tank of a volatile liquid comprising steps of installing a vertical tower having a sealed volume A inside said tank, wherein the volume B of said tank is much larger than volume A of said vertical tower, volume A of said vertical tower allows fluid to enter from the lower part of the tower wherein the top of said vertical tower is close to the top of said tank, thereby enabling leakage measurement to be made when said tank is completely empty by completely immersing said vertical tower at the bottom close to bottom of said tank, installing at least two pressure sensors PS1 and PS2, wherein said pressure sensor PS1 shows the vapour pressure in larger volume B of said tank, sealing volume A of said vertical tower, which allows said pressure sensor PS2 to show a leak proof value of vapour pressure wherein the difference of the two pressure readings read through said pressure sensors PS1 and PS2 gives the indication of the leakage when there is any leakage in the larger volume B of said tank and since fluid inside the tank is at the same temperature for volume A and B so there should be minor difference between the two pressure values. A solenoid valve is installed at said vertical tower, which is normally closed at the top of volume A of said vertical tower, switching on said solenoid valve to connect Volume A of said vertical tower to volume B of said tank before making a comparative measurement, thereby allowing the pressures in volume A and B to equalize, comparing the pressure values of said pressure sensors PS1 and PS2 after a fixed duration of time, allowing to avoid a wrong reading, for instance the pressure of volume A of said vertical tower result in incorrect value due to liquid compression after refueling, or driving over bumps or by using a differential pressure sensor to show the difference of pressure between volume A of said vertical tower and volume B of said tank or by installing a switching valve exposed to a single pressure sensor initially to the volume A of said vertical tower, followed by volume B, or vice versa and said switching valve is a single three way valve and or as per convenience it is a two way valves. Said volatile liquid includes but is not limited to gasoline, chloroform and alike.
Referring to Figure 1, a tower attached to the tank (1) bottom is depicted. A vertical tower (3’) having a volume A (3) is installed inside said tank (1), wherein the volume B (4) of said tank (1) is much larger than volume A (3) of said vertical tower (3’).
Referring to Figure 2, a tower attached to the tank (1) top along with filing cap (5) is depicted. Volume A (3) of said vertical tower (3’) allows fluid to enter from the lower part of the tower (3’) wherein the top of said vertical tower (3’) is close to the top of said tank (1).
Referring to Figure 3, a bulge in the tank (1) top to show the position of the tower (3’) is depicted. Leakage measurement is enabled to be made when said tank (1) is completely empty by completely immersing said vertical tower (3’) at the bottom close to bottom of said tank (1).
Referring to Figure 4, pressure sensors PS1 (6) and PS2 (7) are depicted. At least two pressure sensors PS1 (6) and PS2 (7) are installed, wherein said pressure sensor PS1 (6) shows the vapour pressure in larger volume B (4) of said tank (1), sealing volume A (3) of said vertical tower (3’), which allows said pressure sensor P2 (7) to show a leak proof value of vapour pressure wherein the difference of the two pressure readings read through said pressure sensors PS1 (6) and PS2 (7) gives the indication of the leakage when there is any leakage in the larger volume B (4) of said tank (1) and keeping the fluid in the tank at the same temperature for volume A (3) and B with a very minor difference between the two pressure values.
Referring to Figure 5, an addition of a solenoid valve (8) is depicted. A solenoid valve (8) is installed at said vertical tower (3’), which is normally closed at the top of volume A (3) of said vertical tower (3’), switching on said solenoid valve to connect Volume A (3) of said vertical tower (3’) to volume B (4) of said tank (1) before making a comparative measurement, thereby allowing the pressures in volume A (3) and volume B (4) to equalize, comparing the pressure values of said pressure sensors PS1 (6) and PS2 (7) after a fixed duration of time, allowing to avoid a wrong reading, for instance the pressure of volume A (3) of said vertical tower (3’) result in incorrect value due to liquid compression after re-fueling, or driving over bumps.
Referring to Figure 6, a differential pressure sensor (9) version instead of two pressure sensors is depicted. A differential pressure sensor (9) is used to show the difference of pressure between volume A (3) of said vertical tower (3’) and volume B (4) of said tank (1).
Referring to Figure 7, a version where a switching valve (10) used to expose a single pressure sensor first to the volume A (3) is depicted. A switching valve (10) is installed, which is exposed to a single pressure sensor initially to the volume A (3) of said vertical tower (3’), followed by volume B (4), or vice versa and said switching valve (10) is a single three-way valve and or as per convenience it is a two-way valve.
Therefore, the present invention provides a method of detecting leak in a tank of a volatile liquid, which enables leakage measurement to be made with a nearly empty tank as well and which is less expensive and requires less extensive calibration. A solenoid valve makes a comparative measurement, by allowing the pressures in tower and tank to equalize, comparison of the pressure values of said pressure sensors is done after a fixed duration of time to avoid a wrong reading and a differential pressure sensor is also used to show the difference of pressure between volumes of vertical tower and tank.
Many modifications and other embodiments of the invention set forth herein will readily occur to one skilled in the art to which the invention pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
The foregoing description of embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. The embodiments were chosen and described in order to explain the principals of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated.
,CLAIMS:CLAIMS

We claim:
1. A method of detecting leak in a tank of a volatile liquid comprising steps of:
(a) installing a vertical tower (3’) having a sealed volume A (3) inside said tank (1) of a volatile liquid (2), wherein said tank (1) have a volume B (4) which is larger than said volume A (3) of said vertical tower (3’) allowing fluid to enter from a lower part of said vertical tower (3’);
(b) instating at least two pressure sensors PS1 (6) and PS2 (7), wherein said pressure sensor PS1 (6) shows vapor pressure in said volume B (4) of said tank (1), and said pressure sensor PS2 (7) shows a leak proof value of vapor pressure of said sealing volume A (3) of said vertical tower (3’);
(c) positioning a solenoid valve (8) at said vertical tower (3’) which when switched on connect said volume A (3) of said vertical tower to said volume B (4) of said tank (1) before making a comparative measurement; and
(d) comparing said vapor pressures measured by said pressure sensors PS1 (6) and PS2 (7) to identify any leakage in said tank while allowing pressure in said volume A (3) and said volume B (4) to equalize, and compare pressure values of said pressure sensors PS1 (6) and PS2 (7) after a fixed duration of time to avoid incorrect value.
2. The method of detecting leak in a tank of a volatile liquid as claimed in claim 1, wherein said pressure sensors PS1 (6) and PS2 (7) is replaceable by a differential pressure sensor (9) to indicate difference of pressure between volume A (3) of said vertical tower (3’) and volume B (4) of said tank (1).
3. The method of detecting leak in a tank of a volatile liquid as claimed in claim 1, wherein said pressure sensors PS1 (6) and PS2 (7) are installed with a switching valve (10) separately at a time.
4. The method of detecting leak in a tank of a volatile liquid as claimed in claim 1, wherein said switching valve (10) is a single three-way valve or a two-way valve.
5. The method of detecting leak in a tank of a volatile liquid as claimed in claim 1, wherein said volatile liquid (2) includes but not limited to gasoline, chloroform.
6. The method of detecting leak in a tank of a volatile liquid as claimed in claim 1, wherein said vertical tower (3’) is immersed close to bottom said tank (1) that assist in identification of said leakage.