DESC:FORM 2

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

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

Title of invention:
A METHOD FOR DETECTING, LOCATING AND RECTIFYING AIR LEAKAGE IN A MARINE VESSEL

Applicant:
Mazagon Dock Shipbuilders Limited
A company Incorporated in India under the Companies Act, 1956
Under Ministry of Defence,
(A Govt. of India Undertaking)
Having address:
Dockyard Road, Mazagon,
Mumbai - 400010, Maharashtra, India

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

CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY
[001] The present application claims priority from Indian provisional application no. 201921007493 filed on 26th February 2019.
TECHNICAL FIELD
[002] The present subject matter described herein, in general, relates to a method for detecting, locating and rectifying air leakage. More specifically, the method relates to a detecting, locating and rectifying localized air leakage in a marine vessel.
BACKGROUND
[003] Generally, an air pressure testing (APT) of localized penetrations of under- water sensor/fittings is carried out in respective compartments. However, there is no way of checking & finding out leakages in underwater sensor/fittings in stand alone mode, as leakage boundaries are inside the equipment. Further, in order to test leakages in respective compartments, more time is required and entire area has to be covered for fulfilling test conditions. This activity is time consuming, requires more manpower and can be tested for limited test pressure up to 0.12 kg/cm² only. The whole compartment is required be engaged for test conditions, hence affecting the work in progress. Thus, there is a need to devise a method to enable air pressure testing of the under-water sensor/fittings in a marine vessel locally.
SUMMARY
[004] Before the present system and method are described, it is to be understood that this application is not limited to the particular machine or an apparatus, and methodologies described, as there can be multiple possible embodiments that are not expressly illustrated in the present disclosures. It is also to be understood that the terminology used in the description is for the purpose of describing the particular versions or embodiments only, and is not intended to limit the scope of the present application. This summary is provided to introduce aspects related to a method for detecting, locating and rectifying air leakage in a marine vessel locally, and the aspects are further elaborated below in the detailed description. This summary is not intended to identify essential features of the proposed subject matter nor is it intended for use in determining or limiting the scope of the proposed subject matter.
[005] The present subject matter discloses a method for detecting, locating and rectifying localized air leakage in a marine vessel. The method comprises mounting an enclosure on the surface of the marine vessel to form an air tight assembly of said enclosure on said surface of the marine vessel to cover the underwater fitting; mounting a pressure gauge and a valve on the opening provided of the said enclosure for filling the pressurized air; connecting a pressurized air source to said valve for applying a predetermined air pressure in the said enclosure; closing the said valve to cut-off the supply of the pressurized air flow from the source to the said enclosure; observing the pressure from the said pressure gauge mounted on the said enclosure for any air leakage based on drop in air pressure after a pre-determined amount of time; on detection of drop in air pressure in enclosure detecting the leakage on the inner side of the marine vessel by soap test; if bubbles are detected on the inner side of the underwater fittings, then the said leakage is rectified after removal of the enclosure; and repeating the steps of connecting the pressurized source to said enclosure till conducting the soap test, on detection of no drop in air pressure after a pre-determined amount of time, then there is no leakage and then enclosure is removed.
BRIEF DESCRIPTION OF THE DRAWINGS
[006] The foregoing summary, as well as the following detailed description of embodiments, is better understood when read in conjunction with the appended drawing. For the purpose of illustrating the disclosure, there is shown in the present document example constructions of the disclosure, however, the disclosure is not limited to the specific methods and apparatus disclosed in the document and the drawing:
[007] The detailed description is described with reference to the accompanying figure. In the figure, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawing to refer like features and components.
Reference Number Description
Enclosure 100
O-ring 103
Pressure gauge 111
Valve 113
Air outlet to enclosure 115

[008] Figure 1 illustrates a method for detecting, locating and rectifying leakage of air in a marine vessel, in accordance with an embodiment of the present subject matter.
[009] Figure 2 illustrates an enclosure for air pressure testing, in accordance with an embodiment of the present subject matter.
[0010] Figure 3 illustrates an enclosure for curved surface.
[0011] Figure 4 illustrates an enclosure for a flat surface.
[0012] Figure 5 illustrates an enclosure fitted with an O-ring.
[0013] Figure 6 illustrates bolts welded at the bottom shell of the ship.
[0014] Figure 7 illustrates enclosure fastened to the bottom shell of the ship.
[0015] Figure 8 illustrates arrangement for localized air pressure testing.
[0016] Figure 9 illustrates pressure gauge fitted in the arrangement.
[0017] Figure 10 illustrates pressure gauge assembly.
[0018] The figure depicts various embodiments of the present disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION
[0019] Some embodiments of this disclosure, illustrating all its features, will now be discussed in detail. The words "comprising", “having”, and "including," and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. Although any systems and methods similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present disclosure, the exemplary, systems and methods are now described. The disclosed embodiments are merely exemplary of the disclosure, which may be embodied in various forms.
[0020] Various modifications to the embodiment will be readily apparent to those skilled in the art and the generic principles herein may be applied to other embodiments. However, one of ordinary skill in the art will readily recognize that the present disclosure is not intended to be limited to the embodiments illustrated, but is to be accorded the widest scope consistent with the principles and features described herein.
[0021] The invention, in general, relates to a method for detecting, locating and rectifying leakage of underwater fittings in dry dock.
[0022] Air Pressure Testing (APT) of localized penetrations of under water sensor/fittings is done by carrying out APTs of respective compartments. However, there is no way of checking & finding out leakages through this underwater sensor/fittings in stand alone mode, as leakage boundaries are inside the equipment. This involves readiness of the compartment and the entire area is required to be brought under test conditions. This activity is time consuming, requires more manpower and can be tested for limited test pressure up to 0.12 kg/cm² only. Moreover, the compartment is engaged for test conditions, affecting the work in progress. This method is not suitable for machinery compartments.
[0023] Figure 1 illustrates a method for detecting, locating and rectifying leakage of air in a ship, in accordance with an embodiment of the present subject matter. The method comprises mounting an enclosure (100) on the surface of the marine vessel to form an air tight assembly of said enclosure (100). The enclosure (100) covers the underwater fittings to form an air tight assembly. The enclosure (100) has an opening for mounting a pressure gauge (111) and a valve (113). A pressurized air source is connected to the enclosure (100). Further, a valve (113) is configured to control the flow of the pressurised air to the said enclosure (100) and a pressure gauge (111) is mounted on the said enclosure (100) to indicate the pressure inside the enclosure (100). The desired air pressure is supplied to the enclosure (100) for a pre-determined amount of time. The desired air pressure applied in said enclosure (100) may be 2.5 kg/cm2. The valve (113) supplying pressurised air is operated to cut-off the supply of the pressurized air flow from the source to the said enclosure (100). After the cut-off of the pressurised air supply to the enclosure (100), the pressure drop, if any, on the pressure gauge (111) of the enclosure (100) is observed. On detection of drop in air pressure in enclosure (100), the leakage is detected on the inner side of the marine vessel by soap test. Air leakage can be identified, when the pressure in the said enclosure (100) falls below the 2.5 kg/cm2. If bubbles are detected on the inner side of the underwater fittings, then the said leakage is rectified after removal of the enclosure (100). Eventually, the steps of connecting the pressurized source to said enclosure (100) till conducting the soap test on detection of no drop in air pressure after a pre-determined amount of time are repeated. Upon detection of no leakage, enclosure (100) is removed. The method for detecting, locating and rectifying localized air leakage in a marine vessel as claimed in claim 1, wherein said enclosure (100) is configured to be mounted on the surface of the marine vessel with an o-ring (103) placed between the enclosure (100) and the surface to make an air tight mounting. The method is enabled for detecting, locating and rectifying of the localized air leakage on the openings mounted with underwater fittings.
[0024] Figure 2 shows an enclosure for air pressure testing. Preparation of enclosure (100) is a one time activity and can be used for testing multiple equipments. Reference numeral 101 denotes an O-ring, 103 refers to brackets for mountings and 105 is a provision for fitment of pressure gauge assembly. The enclosure (100) is installed at the bottom of the ship where under water sensor is installed. A groove is created on the enclosure so that an O-ring (101) can be placed to make the enclosure (100) air tight. Further, the pressure pipe is connected to the enclosure (100) and desired pressure is applied. Bolts are welded on the bottom shell of the ship. The enclosure (100) is installed by fastening the nut to the welded bolts. The enclosure (100) can be used on a flat as well as a curved surface of the ship. Air pressure gauge (111) along with nozzle is connected to the test setup. Air pressure pipe is connected to the valve and the desired air pressure is then applied. In case leakage is observed, the enclosure is removed and the leakage point is identified and rectified. After the leakage point is rectified, the process of verifying leakage is carried out again.
[0025] Figure 3 shows an enclosure (100) for curved surface.
[0026] Figure 4 shows an enclosure (100) for a flat surface.
[0027] Figure 5 shows an enclosure (100) fitted with an O-ring (101).
[0028] Figure 6 shows bolts (107) welded at the bottom shell of the ship.
[0029] Figure 7 shows enclosure (100) fastened to the bottom shell of the ship.
[0030] Figure 8 shows arrangement for localized air pressure testing. Reference numeral 109 refers to the pipe connected to the enclosure carrying pressurized air and 111 refers to pressure gauge for indicating pressure inside the enclosure.
[0031] Figure 9 shows pressure gauge 111 fitted in the arrangement.
[0032] Figure 10 shows pressure gauge assembly. Reference numeral 113 refers to a valve, 111 refers to pressurized air source and 115 refers to air outlet to enclosure.
[0033] One embodiment of the invention can be used in installation of electrical underwater system’s sensors for e.g. EM LOG transducers echo sounder, transducer, ICCP Anodes and reference electrodes.
[0034] Another embodiment of the invention can be used for fitment of sea tubes and OBD’s.
[0035] Local air pressure testing has no restriction on air pressure. Any desired air pressure could be applied to the newly installed equipment as against the limited air pressure that can be applied in conventional air pressure testing. Further, in conventional air pressure testing, limited air pressure may affect other equipment, bulk head, deck head or deck of the compartment.
[0036] In local air pressure testing there is no need for the entire equipment to be air tight during testing as against the entire compartment to be air tight during air pressure testing by conventional method of testing air pressure.
[0037] Local air pressure testing can be performed independently and at the same time compartment could be used for other work whereas conventional air pressure testing restricts any other type of work that is carried out in the same compartment.
[0038] Local pressure can be used at any stage of installation whereas conventional air pressure testing is not feasible during different stage of installing the new equipment.
[0039] In local air pressure testing, air pressure can be applied from outside or inside of the ship whereas in conventional air pressure testing air pressure can be applied only from the inside.
[0040] Local air pressure testing is quite efficient in investigating multiple glands of the same equipment whereas in conventional air testing method multiple glands in the same equipment are difficult to diagnose.
[0041] Exemplary embodiments discussed above may provide certain advantages. Though not required to practice aspects of the disclosure, these advantages may include those provided by the following features.
[0042] Some object of the present invention is to increase reliability of the tested equipment.
[0043] Some object of the present invention results in reduced labour required for the activity.
[0044] Some object of the present invention reduces cost as it involves applying pressure only at the unit installed instead of the entire compartment.
[0045] Some object of the present invention ensures that the method can be implemented at any surface across the ship’s hull.
[0046] Some object of the present invention enables reduces requirement of labour as activity of sealing the compartment is eliminated.
[0047] The present subject matter enables multiple and multi-stage testing without impacting other activities in same compartment.
,CLAIMS:
1) A method for detecting, locating and rectifying localized air leakage in a marine vessel comprises the steps of:
mounting an enclosure (100) on the surface of the marine vessel to form an air tight assembly of said enclosure (100) on said surface of the marine vessel to cover the underwater fitting;
mounting a pressure gauge (111) and a valve (113) on the opening provided of the said enclosure (100) for filling the pressurized air;
connecting a pressurized air source to said valve (113) for applying a predetermined air pressure in the said enclosure (100);
closing the said valve (113) to cut-off the supply of the pressurized air flow from the source to the said enclosure (100);
observing the pressure from the said pressure gauge (111) mounted on the said enclosure (100) for any air leakage based on drop in air pressure after a pre-determined amount of time;
on detection of drop in air pressure in enclosure (100) detecting the leakage on the inner side of the marine vessel by soap test;
if bubbles are detected on the inner side of the underwater fittings, then the said leakage is rectified after removal of the enclosure (100); and repeating the steps of connecting the pressurized source to said enclosure (100) till conducting the soap test
on detection of no drop in air pressure after a pre-determined amount of time, then there is no leakage and then enclosure (100) is removed.
2) The method for detecting, locating and rectifying localized air leakage in a marine vessel as claimed in claim 1, wherein said enclosure (100) is configured to be mounted on the surface of the marine vessel with an o-ring (103) placed between the enclosure (100) and the surface to make an air tight mounting.
3) The method for detecting, locating and rectifying localized air leakage in a marine vessel as claimed in claim 1, wherein the desired air pressure applied in said enclosure (100) may be 2.5 kg/cm2.
4) The method for detecting, locating and rectifying localized air leakage in a marine vessel as claimed in claim 1, wherein the air leakage can be identified when the pressure in the said enclosure (100) falls below the 2.5 kg/cm2.
5) The method for detecting, locating and rectifying localized air leakage in a marine vessel wherein, detecting, locating and rectifying of the localized air leakage is carried out on the openings mounted with underwater fittings.
6) The method for detecting, locating and rectifying localized air leakage in a marine vessel wherein, said enclosure (100) has an opening for mounting a pressure gauge (111) and a valve (113).