Title of Invention

A GAS LEAK TESTING DEVICE FOR A GAS CYLINDER & METHOD

Abstract A gas leak testing device for a gas cylinder, typically an LPG cylinder the said device comprising: i)a see through body in which is provided, means for detecting and testing gas leak from the pin of a gas cylinder and means for detecting and testing gas leak from the O-ring of a gas cylinder, alternatively; and ii)separate nozzles for locating and removably fitting the said device within the nozzle of a gas cylinder to perform alternatively pin leak test and O-ring leak test.
Full Text COMPLETE AFTER PROVISIONAL
FORM - 2 LEFT ON
6 J AN 2006'
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE


Specification
(See section 10 and rule 13)
A GAS LEAK TESTING DEVICE FOR A GAS CYLINDER
HINDUSTAN PETROLEUM CORPORATION LTD.,
an Indian Company
of Hindustan Bhavan, 3rd floor, 8, S.V.Marg, Mumbai 400 001,
Maharashtra, India




THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.

Field of Invention:
This invention relates to testing equipment.
In particular, this invention relates to a gas leak testing equipment.
Still particularly, this invention relates to a testing equipment for domestic gas cylinders, typically LPG cylinders.
Background of the invention: Introduction:
The use of LPG for domestic cooking purposes is very common. LPG is bottled in a cylinder at the LPG plant and delivered to households for use. The gas is filled into the cylinder using sophisticated equipment through the cylinder pin. Sealing components ensure that gas does not leak from the cylinder. The filled cylinders are then transported to dealers for distribution, which are delivered to the households.
The LPG cylinder is in the shape of a bottle. A metal nozzle is provided at the operative top end of the cylinder. The gas cylinder is attached to a gas stove by means of a regulator and a rubber tube attached to the regulator. The nozzle of the regulator is fitted on the nozzle of the cylinder. When the knob of the regulator is turned to the on position it presses the pin of the cylinder and the pressurized liquefied gas is released. A rubber tube connected to the regulator carries the gas vapours to the stove. The flow of gas vapours, out of the burners of the stove is regulated by knobs provided on the stove.
The pin of the cylinder is a cylindrical metal component, which is used to release the liquefied gas in the form of vapours when the regulator is fitted to the nozzle of the cylinder. The pin of the cylinder is spring loaded. An O-ring is used as a gasket for sealing purposes. The O-ring is designed to be seated in a groove or housing that keeps the ring in place. When the nozzle of the regulator is fitted to the nozzle of the cylinder the O-ring gets compressed and creates a strong seal along the surfaces of contact of the two nozzles thus preventing the leak of LPG gas vapours form the cylinder. O-rings can withstand a very large amount of pressure and are therefore used in LPG cylinders to prevent leakage of the
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LPG vapours. The O-rings are typically made of polybutylene, silicone, neoprene, nitrile rubber and the like.
The quantity of gas present in the cylinder depletes as it is used. The empty cylinders are then returned to the distributor and sent to the LPG plant for refilling. After refilling, these cylinders are sent to the distribution centers, which in turn deliver the cylinders to households.
During the course of a number of distribution cycles, different people handle the cylinders. The cylinders are sturdy in construction, but some components are prone to fail with time. Eventually due to rough use by unskilled labourers at the LPG plant, distribution centers and people at the user end, these components tend to give way.
At the LPG plant sophisticated equipment is used to check the cylinder for the presence of leak. Such equipment check the body, the pin, the O-ring and the other components of a cylinder. However the use of such sophisticated expensive equipment at distribution centers and at homes is not practically possible. Hence it is difficult to pin point a precise location of such leakage on a cylinder. The possibility of leakage through the pin of the cylinder and through the O-ring is common.
Due to mishandling the pin gets damaged and leaks gas even when the regulator is not connected. The leak through the pin is usually a low volume leak. The mishandling may also lead to cracking of the O-ring due to which the gas leaks through the O-ring. A leak occurring through the O-ring is a high volume high pressure leak.
At the user end it is not practically possible to use sophisticated equipment to check the leak occurring through the pin as well as the O-ring of the cylinder. Hence there is a need for a simple, portable, easy to use, lightweight, hand held device, which can be used by any unskilled labourer at distribution centers or by housewives and people at home. The device should provide a quick, inexpensive, efficient method requiring minimum mental effort and knowledge, for checking the presence of a leak in a gas cylinder, typically a domestic LPG cylinder.
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Description of Prior Art:
U.S. Patent No. 4068522 discloses a gas leak detector incorporated in a rotary valve intended to be mounted in a gas system adjacent the source of gas, the detector valve having a first position permitting flow from the source into the system, and a second position in which any gas entering the system due to a large or small leak in the system is made visible as it passes through a bubble chamber. The disclosed detector uses multiple step operation, which is very complicated, time consuming and can be used only for rotary valves.
U.S. Patent No. 4453399 discloses a leak detecting method which utilizes a pressure vessel for holding gas under pressure and a transparent chamber partly filled with liquid.
U.S. Patent No. 4895018 discloses a gas leakage detector includes a housing, an inlet coupling, internal fluid flow path and an outlet coupling enabling the housing to be installed and coupled permanently in-line with a gas supply line. Such a device will have to be continuously attached to the supply line thus increasing the inventory of a plant where such device can be used.
U.S. Patent No. 6003363 discloses an improved bubble leak tester, and associated method for performing a leak test and operating the leak tester, to test for leaks in a test part. The disclosed device cannot perform pin leak test and O-ring leak test using a single device.
U.S. Patent No. 6912890 discloses a device for leak-testing a pipeline system, of the type having a test tee fitting in a standpipe, includes a generally circular base plate for engaging an opening of the test tee, a wrench collar for tightening the base plate in the test tee, and a threaded bushing for filling the standpipe with water. The disclosed apparatus uses many parts hence it is not practically possible to use them at home.
None of the aforementioned means can be extended to perform pin leak test and O-ring leak test of a LPG cylinder.
This invention seeks to overcome the limitations of the prior art.
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Object of this invention is to provide a simple, portable, easy to use, lightweight, hand held gas leak testing device.
Another object of this invention is to provide a single gas leak testing device, which can be used to perform pin leak test as well as O-ring leak test.
Yet another object of this invention is to provide a gas leak testing device, which can be used by unskilled labourers at distribution centers and by housewives.
Yet another object of this invention is to provide a gas leak testing device with the least number of fittings and no moving parts.
Yet another object of this invention is to provide a gas leak testing device without any electrical or electronic circuitry.
Yet another object of this invention is to provide a quick, inexpensive, efficient method requiring minimum mental effort and knowledge, for checking the presence of a leak in a gas cylinder, typically a domestic LPG cylinder.
Summary of the invention:
In accordance with one practical embodiment of such a device, this invention envisages a hand held leak tester for a gas cylinder, typically a LPG cylinder that performs both tests viz (i) Pin Leak Test and (ii) O-Ring Leak Test and is devoid of any electrical or electronic circuitry.
A gas leak testing device for a gas cylinder, typically an LPG cylinder the said device
comprising:
(i) a see through body in which is provided, means for detecting and testing
gas leak from the pin of a gas cylinder and means for detecting and testing gas leak from the O-ring of a gas cylinder, alternatively; and
(ii) separate nozzles for locating and removably fitting the said device
within the nozzle of a gas cylinder to perform alternatively pin leak test and O-ring leak test.
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Typically, the body of the said device is defined by a see through hollow cylindrical tube open at both ends, a top end cap and a bottom end cap fitted to the operative top and operative bottom end of the said cylindrical tube, the top and bottom end cap having predetermined apertured recesses and an opening for fitting the pin leak testing means.
Typically, the O-ring leak detecting means comprises:
(a) a first nozzle adapted to be fitted in a first recess in the lower end cap to communicate with the hollow within the body of the device ; and
(b) a whistle provided in an apertured recess in the upper end cap adapted to communicate with the hollow within the body of the device.
Typically, the means of performing the pin leak test being isolated from the means of performing the O-ring leak test the said pin leak testing and indicating means comprises:
(a) a second nozzle adapted to be fitted in a second recess in the lower end cap and
extending there from;
(b) an indicating tube housed in a see through hollow cylindrical housing tube
provided within the said body and fitted in a third recess in the lower end cap such
that the second nozzle and the indicating tube are in communication with each other
via passages in the lower end cap, the said housing extending to the top cap and
fitted in a hole; and
© a removable closure means provided for the housing for filling and securing liquid, typically water, in the housing and the indicating tube.
Typically, pin leak testing means is provided with a non linear passage defined through the second nozzle, the end caps, the indicating tube, the housing for the indicating tube and the closure for the passage of the leaked gas from the cylinder, under reduced pressure.
Typically, a method for performing Pin leak test on a gas cylinder, typically an LPG cylinder using the said device having means for detecting leak through the pin of a gas cylinder said means including an indicating tube, said method consisting the steps of:
(i) filling water inside the hollow cylindrical housing tube through the water inlet upto a level marked by a coloured band present on the indicating tube; (ii) locating and fitting the second nozzle on the nozzle of the cylinder; and
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(iii) observing the presence or absence of a leak through the pin of the cylinder in the form of bubbles coming out of the aperture in the indicating tube.
Typically, the see through hollow cylindrical tube is open at both ends.
Typically, the see through hollow cylindrical tube is at least partially transparent.
Typically, the see through hollow cylindrical tube is made from a material selected from a group of materials such as polycarbonates, polyacrylates, synthetic polymeric material, acrylic and the like.
Typically, a top end cap is fitted to the operative top end of the see through cylindrical tube.
Typically, the top end cap has hole and an apertured recess.
Typically, the hole of the top end cap serves as the water inlet.
Typically, the recess in the top end cap accommodates the whistle.
Typically, the recess communicates with the hollow within the device via a passage that extends from the aperture in the recess.
Typically, the top end cap is made from a material selected from a group of materials such as polycarbonates, polyacrylates, synthetic polymeric material, acrylic and the like.
Typically, a bottom end cap is fitted to the operative bottom end of the see through cylindrical tube.
Typically, the bottom end cap has three apertured recesses.
Typically, the first apertured recess accommodates the O-ring leak testing nozzle.
Typically, the second apertured recess accommodates pin leak testing nozzle.
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Typically, the third apertured recess accommodates the indicating tube.
Typically, a the first and the second recess communicate via a passage extending from the aperture in the first recess to the aperture in the second recess.
Typically, the third recess communicates with the hollow within the device via a passage that extends from the aperture in the third recess.
Typically, the bottom end cap is made from a material selected from a group of materials such as polycarbonates, polyacrylates, synthetic polymeric material, acrylic and the like.
Typically, a first nozzle is an O-ring leak testing nozzle adapted to be fitted into the first recess of the lower end cap to communicate with the hollow within the body of the device.
Typically, the O-ring leak testing nozzle has two apertures one on the either side of the nozzle and a passage extending from the aperture which communicates with a centrally located passage in the nozzle.
Typically, the centrally located passage of the nozzle and the passage extending from the first recess are in aligned engagement with each other.
Typically, the gas entering the hollow within the body of the device is at the same pressure as the gas entering the O-ring leak testing nozzle when the nozzle is placed on the nozzle of the cylinder.
Typically, a whistle is provided in the apertured recess in the upper end cap adapted to communicate with the hollow within the body of the device.
Typically, a second nozzle is a pin leak testing nozzle adapted to be fitted into the second apertured recess of the lower end cap.
Typically, the pin leak testing nozzle has a centrally located passage within the nozzle.
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Typically, the indicating tube in a cylindrical tube open at one end and is adapted to be fitted into the third recess of the lower end cap.
Typically, the indicating tube has two apertures one on either side of the tube through which gas bubbles out when a leak is detected.
Typically, the indicating tube is housed in a see through hollow cylindrical tube.
Typically, the indicating tube is placed concentrically within the see through hollow cylindrical tube.
Typically, the see through hollow cylindrical housing tube is fitted in the hole provided in the upper end cap.
Typically, a water column is formed with the housing tube.
Typically, a removable closure means with an extending cylindrical tube is provided to seal the water inlet.
Typically, an aperture is provided on the top surface of the removable closure means.
Typically, an aperture is provided on the extending cylindrical tube.
Typically, a passage extends from the aperture on the top surface to the aperture on the extending tube.
A method for performing O-ring leak test on a gas cylinder, typically a LPG cylinder the
said method comprising the following steps:
(i) placing the O-ring leak testing nozzle on the nozzle of the cylinder;
(ii) applying a slight downward pressure on the pin of the cylinder; and
(iii) listening to the audible indicator, which indicates a leak through the o- ring of the cylinder
Typically, the gas leak testing device has no moving parts.
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Typically, the gas leak testing device has no electrical or electronic circuitry.
The two leak tests that are performed using this device are:
1. Pin Leak Test
2. 0- Ring Leak test
Principle of working of the tests:
1. Pin Leak Test
The principle of working of the pin leak test is that gas being lighter than water it forms bubbles in water and these bubbles move upward and escape. In the pin leak test water is used as the medium and bubbles of LPG vapours as indicator of the leak.
The sensitivity of the device can be regulated by varying the height of the water column. As the height of the water column is increased, the negative pressure exerted on the gas vapours increases, thus reducing the sensitivity of the device.
The water level to be maintained in the leak tester is decided based on the sensitivity requirement of the leak tester. The sensitivity at the LPG plant is maintained at 0.5 gms/hr, the level of water in the gas leak testing device is kept such that the device measures with the same sensitivity at distribution centers and at homes. The sensitivity of the pin tester is 0.5 gms /hr, the maximum test time is 15seconds.
2. O- Ring Leak Test
The principle of working of the O-ring leak test is that when a gas at high pressure is passed through a specially designed constricted opening it tends to produce a whistling sound.
Brief description of the drawings:
The invention will be described in detail with reference to a preferred embodiment. Reference to this embodiment does not limit the scope of the invention, which is limited only by the scope of the claims.
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In the drawings:
Figure 1 illustrates the overview of the gas leak testing device;
Figure 2 illustrates the top view of the gas leak testing device;
Figure 3 illustrates the bottom view of the gas leak testing device;
Figure 4 illustrates the sectional view of the pin leak testing nozzle;
Figure 5 illustrates the sectional view of the O-ring leak testing nozzle;
Figure 6 illustrates the sectional view of the cylindrical tube of the pin leak testing
equipment;
Figure 7 illustrates the sectional view of the closure with an elongated cylindrical tube that
seals the water inlet of the leak testing device;
Figure 8 illustrates the sectional view of the bottom end cap in an operative configuration;
Figure 9 illustrates the sectional view of the top end cap in an operative configuration;
Figure 10 illustrates the sectional view of the inner cylindrical tube;
Figure 11 illustrates the sectional view of the outer cylindrical tube;
Figure 12 illustrates the operational configuration of the gas leak testing device when used
to perform the pin leak test;
Figure 13 illustrates the path traversed by the gas vapours while performing the pin leak
test;
Figure 14 illustrates the operational configuration of the gas leak testing device when used
to perform the O-ring leak test; and
Figure 15 illustrates the path traversed by the gas vapours while performing the O-ring leak
test.
In the drawings the following reference numerals represent the components mentioned alongside:
Component No. Component Name
10 gas leak testing device
12 outer hollow cylindrical tube
14 top end cap
16 bottom end cap
18 closure
20 extending cylindrical tube
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22 pin leak testing nozzle
24 o-ring leak testing nozzle
25 aperture of the O-ring leak testing nozzle
26 inner hollow cylindrical tube
28 cylindrical tube
30 aperture of the cylindrical tube
32 whistle
34 outlet of the whistle
36 washer used as fitment means
38 tapering head end of the pin leak testing nozzle
40 flat back end of the pin leak testing nozzle
42 recesses of the pin leak testing nozzle
44 narrow passage of the pin leak testing nozzle
46 tapering head end of the O-ring leak testing nozzle
48 flat back end of the O-ring leak testing nozzle
50 recess of the O-ring leak testing nozzle
52 narrow passage of the O-ring leak testing nozzle
54 recesses of the cap
55 narrow passage provided in the extending cylindrical tube of the
56 recess provided to accommodate the pin leak testing nozzle
58 recess provided to accommodate the O-ring leak testing nozzle
60 narrow passage for gas vapours
61 recess for accommodating a part of the pin leak testing equipment
62 narrow passage for gas vapours

64 hollow recess which serves as the water inlet
65 recess for accommodating the whistle
66 narrow passage for gas vapours to escape from the outer hollow cylindrical tube
68 pin of the cylinder
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Detailed description of the invention:
The apparatus and method for testing the presence of a leak will now be explained with reference to the figures 1 to 15 of the accompanying drawings.
Figure 1 illustrates the overview of the gas leak testing device (10). The gas leak testing device is defined by a body which is made of a hollow cylindrical tube hereinafter called as outer hollow cylindrical tube (12). The outer hollow cylindrical tube (12) is at least partially transparent, preferably double walled and may be made of synthetic polymeric material. The tube (12) is made from a material which is at least one selected from a group of materials such as polycarbonates, polyacrylates, synthetic polymeric material and the like. Preferably the tube (12) is made of acrylic.
The tube (12) is open at both ends. The operative top end of the tube (12) is fitted with an end cap (14) and the operative bottom end of the tube (12) is fitted with an end cap (16). The cap (14) and the cap (16) are sealed to the operative top and bottom ends of the outer hollow cylindrical tube (12). An airtight compartment is therefore formed within the tube (12). The cap (14) and the cap (16) may be sealed with the help of an adhesive or by heat sealing or the like operations. The adhesives are chosen such that they do not react with LPG and are able to withstand the pressure.
The cap (14) is provided with a hole (64) and an apertured recess (66) as particularly seen in figure 9 of the accompanying drawings. The cap (16) is provided with three apertured recesses (56), (58) and (61) as particularly seen in figure 8 of the accompanying drawings. The hole (64) on the cap (14) serves as a water inlet, recess (65) accommodates the whistle (32). A closure (18) with an extending cylindrical tube (20) is provided which seals the water inlet provided on the cap (14). A passage for the gas accumulated in the inner hollow cylindrical (26) is in the form of an aperture (21) provided on the cylindrical tube (20). The closure (18) is provided with an aperture (19) on the operative top surface, which allows the gas vapours entering the cylindrical tube (20) to escape. A pin leak testing nozzle (22) is fitted into the recess (56) as seen particularly in figure 13 of the accompanying drawings. An 0- ring leak testing nozzle (24) is fitted into the recess (58) of the cap (16) as seen particularly in figure 15 of the accompanying drawings.
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An inner hollow cylindrical tube (26) is fitted between the recess (61) of the cap (16) and the hole (64) as seen particularly in figure 13 of the accompanying drawings. A cylindrical tube (28) closed at one end is concentrically placed inside the inner hollow cylindrical tube (26). The cylindrical tube (28) has an aperture (30), which is provided for the gas to bubble out while performing the pin leak test. The inner hollow cylindrical tube (26) is filled with water to form the water column. Water is filled upto a certain predetermined level, which is indicated by a coloured band on the cylindrical tube (28).
A whistle (32) is provided with an outlet (34), which produces a whistling sound in case of 0- ring leak test failure. The whistle (32) is fitted in the recess (65) as seen particularly in figure 15 of the accompanying drawings.
Figure 2 illustrates the operative top view of the gas leak testing device. A circular closure (18) with an extending cylindrical tube (20) as particularly seen in figure 7 of the accompanying drawings is provided to seal the water inlet. An aperture (19) is provided on the operative top surface of the closure (18), which allows the gas vapours entering the cylindrical tube (20) to escape. A whistle (32) is provided, which produces a whistling sound in case of O-ring leak test failure. Figure 3 illustrates the operative bottom view of the gas leak testing device. Two nozzles are fitted into the cap (16) of the gas leak testing device. One is the pin leak testing nozzle (22) and the other is the O-ring leak testing nozzle (24). The nozzles (22) and (24) are fitted into the cap (16) by means of fitting means and washers (36).
Figure 4 illustrates the sectional view of the pin leak testing nozzle (22). The nozzle (22) has a tapering head end (38) and a flat back end (40). A recess (42) is provided along the body of the nozzles, which accommodates the O-ring and ensures better fitment of the nozzle (22) into the recess (56) of the cap (16) (not shown in figure). The nozzle (22) has a small centrally located passage (44), which is uniform throughout the nozzle (22). The passage (44) provides a passage for the gas, which leaks from around pin. According to one preferred embodiment of this invention the dimensions of the different parts of the pin leak testing nozzle are mentioned below.
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MARKINGS
DIMENSIONS
A-outer diameter of the back end of the nozzle (22) 12mm dia
B-distance between the recess (42) 9mm dia
C-diameter of the notch (39) 7.2mm dia
D-width of the notch (39) 2mm
E-width of the recess (42) 2mm
F-distance between the flange (43) and the back end (40) of the of the nozzle 10mm
G-width of the flange (43) 2.5mm
H-width of the recess (45) 5.5mm
I-width of the flange (37) 3mm
J-length of the tapering head end (38) of the nozzle (22) 8.7mm
L-overall length of the nozzle (22) 31.7mm
N-diameter of the passage (44) 1.5mm dia
O-outer diameter of the operative front end of the nozzle (22) 9mm dia
P-diameter of 10.2mm dia
Q-diameter of the flange (37) 12mm dia
R-diameter of the recess (45) 10.6mm dia
S-diameter of the flange (43) 18mm dia
Figure 5 illustrates the sectional view of the O-ring leak testing nozzle (24). The nozzle (24) has a tapering head end (46) and a flat back end (48). A recess (50) is provided along the body of the nozzle, which accommodates an O-ring and ensures better fitment of the nozzle (24) into the recess (58) of the cap (16) (not shown in figure). The nozzle (24) has a small aperture (25) located on the side of the nozzle (24) and a centrally located passage (52) that is uniform throughout the nozzle. The passage (52) provides a passage for the gas, which leaks from the O-ring. According to one preferred embodiment of this invention the dimensions of the different parts of the O-ring leak testing nozzle (22) are mentioned below.
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MARKINGS
DIMENSIONS
Al- outer diameter of the back end of the nozzle (24) 12mm dia
Bl- distance between the recess (52) 9mm dia
CI- diameter of the notch (49) 7.2mm dia
Dl- width of the notch (49) 2mm
El- width of the recess (52) 2mm
Fl- distance between the flange (51) and the back end (48) of the of the nozzle 10mm
Gl-width of the flange (51) 2.5mm
HI- width of the recess (53) 5.5mm
11- width of the flange (47) 3 mm
Kl- length of the tapering head end (46) of the nozzle (24) 10.8mm
M- overall length of the nozzle (24) 33.8mm
Nl- diameter of the passage (52) 1.5mm dia
01- outer diameter of the operative front end of the nozzle (24) 9mm dia
PI-diameter of 10.2mm dia
Ql- diameter of the flange (47) 12mm dia
R1 - diameter of the recess (53) 10.6mm dia
SI- diameter of the flange (51) 18mm dia
Figure 6 illustrates the sectional view of the cylindrical tube (28) of the pin leak testing equipment. The cylindrical tube (28) is concentrically placed inside the inner hollow cylindrical tube (not shown in this figure). The cylindrical tube (28) has an aperture (30) through which the gas bubbles out, which indicates a leak in the pin of the cylinder.
Figure 7 illustrates the sectional view of the closure (18) with an elongated cylindrical tube (20) that seals the water inlet of the leak testing device. Water is filled upto a predetermined level inside the inner hollow tube (26) through the inlet. The closure (18) then seals the inlet. A recess (54) is provided on the sides of the extending tube (20), which accommodates an O-ring and ensure better fitment of the closure (18) into the hole (64). An aperture (21) is provided on the extending tube (20), which serves as the escape route for the gas vapours entering the inner hollow cylindrical tube. A centrally located passage (55) is provided in the elongated cylindrical tube (20) for the passage of the gas, which enters the hollow cylindrical tube (20) while performing the pin leak test. An aperture (19) is provided on the operative top surface of the closure (18), which allows the gas in the passage (55) to escape. According to one preferred embodiment of this invention the
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dimensions of the different parts of the O-ring leak testing nozzle (24) are mentioned below.

MARKING DIMENSIONS
A5-diameter of the closure (18) 12mm dia
B5-diameter of the aperture (19) 9mm dia
C5-width of the aperture (19) 3mm
D5-width of the recess (54) 2mm
E5-width of the recess (53) 1mm
F5-distance of the recess (54) from the front end of the extending tube 6mm
G5-diameter of the passage (55) 6mm dia
H5-diameter of the extending cylindrical tube (24) 9mm dia
15-distance between the passage (55) and the end of extending cylindrical tube (20) 3 mm
J5-distance between the flange (41) and the end of the extending cylindrical tube (20) 50mm
K5-distance between the one end of the closure and the flange 10mm
L5- width of the closure (18) 6mm
M5-overall length of the closure (18) and the extending cylindrical tube (20) 66mm
Figure 8 illustrates the sectional view of the bottom end cap in an operative configuration. The nozzle holder accommodates both the pin leak testing nozzle and the O-ring leak testing nozzle. Three apertured recesses (56) and (58) are provided on the cap (16). In the operative configuration the recess (56) accommodates the pin leak testing nozzle. The apertured recess (56) is external to the device while the apertured recess (61) is internal to the device. The recess (61) accommodates the inner hollow cylindrical tube (26). The apertures of both the recesses (56) and (61) are linked together by a passage (60). The passage (60) is placed such that the passage of the pin leak test nozzle and the passage (60) are not aligned, hence the gas vapours are deflected before entering the passage (60) and reduction in the pressure of vapours takes place. In the operative configuration the recess (58) accommodates the O-ring leak testing nozzle. The aperture in the recess (58) is centrally located and a narrow passage (62) extends from the aperture. The passage (62) is aligned with the passage of the pin leak testing nozzle, hence the high pressure gas vapours which leak from the O-ring enter the outer hollow cylindrical tube
Figure 9 illustrates the sectional view of the top end cap in an operative configuration. A hole (64) is provided through which the water can be poured into the inner hollow
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cylindrical tube. In the operative configuration the apertured recess (65) accommodates the whistle. A narrow passage (66) extends from the recess (65), which carries the high pressure gas from the outer hollow cylindrical tube of the gas leak testing device to the whistle.
Figure 10 illustrates the sectional view of the inner hollow cylindrical tube and Figure 11 illustrates the sectional view of the outer hollow cylindrical tube. The outer hollow cylindrical tube (12) and the inner hollow cylindrical tube (26) are both double walled, which are at least partially transparent. The tube (12) and the tube (26) are open at both ends. The outer hollow cylindrical tube (12) forms the body of the leak testing device. The inner hollow cylindrical tube (26) forms a part of the pin leak testing equipment. The outer hollow cylindrical tube (12) has a larger diameter as compared to the inner hollow cylindrical tube (26).
Figure 12 illustrates the operational configuration of the gas leak testing device when used to perform the pin leak test. The inner hollow cylindrical tube (26) is filled with water upto a level indicated by a coloured band on the cylindrical tube (28). The pin leak testing nozzle (22) is then placed on the nozzle of the cylinder. The test time is around 15 seconds. If bubbles come out of the aperture (30) in the cylindrical tube (28) it indicates the presence of a leak.
Figure 13 illustrates the path traversed by the gas vapours while performing the pin leak test. The gas vapours that leak enter the pin leak testing nozzle (22) through the passage (44) and move upwards. The vapours come out of the passage (44) into the recess (56) where the pin leak testing nozzle (22) is fitted. In the recess (56) the gas vapours are deflected through 90 degrees approximately this helps in reducing the pressure of the gas vapours entering the passage (44). The deflected gas vapours enter the passage (60), move upward and enter the recess (61) in which the inner hollow cylindrical tube is fitted. The gas vapours are again deflected through 90 degrees approximately thus further reduction of the pressure occurs. The gas vapours then enter the passage (70) and bubble out through the aperture (30). The gas bubbles rises through the column of water and the vapours get accumulated in the inner hollow cylindrical tube. The gas vapours do not have an escape route hence it enters the aperture (21) in the cylindrical tube (20). The vapours the move up
18;

the passage (55) and escape through the aperture (19) provided on the operative top surface of the closure (18).
Figure 14 illustrates the operational configuration of the gas leak testing device when used to perform the O-ring leak test. The O-ring leak testing nozzle (24) is placed on the nozzle of the cylinder and the pin is pressed down. After a few seconds if a whistling sound is heard then it indicates a leak in the O-ring of cylinder.
Figure 15 illustrates the path traversed by the gas vapours while performing the O-ring leak test. The gas vapours that leak from the O-ring enter the O-ring leak testing nozzle (24) through the aperture (25) and move upwards in the passage (52). The vapours come out of the passage (52) into the recess (58) where the O-ring leak testing nozzle (24) is fitted. The opening of the passage (52) and the opening of the passage (62) are aligned in such a way that no drop in pressure takes place. The gas under high pressure enters the passage (62), move upward and enter the outer hollow cylindrical tube (12) of the device. The gas vapours get accumulated in the outer hollow cylindrical tube (12) of the device. The gas vapours do not have an escape route hence it enters the passage (66). The high pressure gas coming out of the passage (66) is then passed to a whistle. As the high pressure gas vapours passes through a constricted opening it produces a whistling sound. The whistling sound indicates a leak in the O-ring.
The method of assembly of the gas leak testing device comprises the following steps:
1. the cylindrical tube (28) is fitted into the recess (61) of the cap (16).
2. the inner hollow cylindrical tube (26) is the fitted concentrically around the cylindrical tube (28).
3. the outer hollow cylindrical tube (12) is the fitted to the cap (16).
4. cap (14) is fitted to the other end of the outer hollow cylindrical tube (12).
5. the cap (16) and the cap (14) are sealed properly to ensure that an air tight compartment is formed.
6. the pin leak testing nozzle (22) and the O-ring leak testing nozzle (24) are then fitted into the recess (56) and (58) respectively of the cap (16).
7. the closure (18) with an extending cylindrical tube (20) is fitted into the recess (64) of the cap (14) to seal the water inlet.
8. the whistle (32) is fitted into the recess (65) of the cap (14).
19

We Claim:
1. A gas leak testing device for a gas cylinder, typically an LPG cylinder the said device
comprising:
(i) a see through body in which is provided, means for detecting and testing gas leak from the pin of a gas cylinder and means for detecting and testing gas leak from the O-ring of a gas cylinder, alternatively; and
(ii) separate nozzles for locating and removably fitting the said device within the nozzle of a gas cylinder to perform alternatively pin leak test and O-ring leak test.
2. A gas leak testing device for a gas cylinder, typically an LPG cylinder as claimed in claim 1, wherein the body of the said device is defined by a see through hollow cylindrical tube open at both ends, a top end cap and a bottom end cap fitted to the operative top and operative bottom end of the said cylindrical tube, the top and bottom end cap having predetermined apertured recesses and an opening for fitting the pin leak testing means.
3. A gas leak testing device for a gas cylinder, typically an LPG cylinder as claimed in claim 2, wherein the see through hollow cylindrical tube is made from a material selected from a group of materials consisting of glass, polycarbonates, polyacrylates, polyesters, polyethylenes or acrylic.
4. A gas leak testing device for a gas cylinder, typically an LPG cylinder as claimed in claim 1, wherein the O-ring leak detecting means comprises:

(a) a first nozzle adapted to be fitted in a first recess in the lower end cap to communicate with the hollow within the body of the device; and
(b) a whistle provided in an apertured recess in the upper end cap adapted to communicate with the hollow within the body of the device.
5. A gas leak testing device for a gas cylinder, typically an LPG cylinder as claimed in
claim 2, wherein the means of performing the pin leak test being isolated from the means of
performing the O-ring leak test the said pin leak testing and indicating means comprises:
(a) a second nozzle adapted to be fitted in a second recess in the lower end cap and extending there from;
20

(b) an indicating tube housed in a see through hollow cylindrical housing tube provided within the said body and fitted in a third recess in the lower end cap such that the second nozzle and the indicating tube are in communication with each other via passages in the lower end cap, the said housing extending to the top cap and fitted in a hole; and
© a removable closure means provided for the housing for filling and securing liquid, typically water, in the housing and the indicating tube.
6. A gas leak testing device for a gas cylinder, typically an LPG cylinder as claimed in claim 5, wherein the pin leak testing means is provided with a non linear passage defined through the second nozzle, the end caps, the indicating tube, the housing for the indicating tube and the closure for the passage of the leaked gas from the cylinder, under reduced pressure.
7. A method for performing Pin leak test on a gas cylinder, typically an LPG cylinder using the said device as claimed in claim 1 having means for detecting leak through the pin of a gas cylinder said means including an indicating tube, said method consisting the steps of:
(i) filling water inside the hollow cylindrical housing tube through the water inlet
upto a level marked by a coloured band present on the indicating tube;
(ii) locating and fitting the second nozzle on the nozzle of the cylinder; and
(iii) observing the presence or absence of a leak through the pin of the cylinder in
the form of bubbles coming out of the aperture in the indicating tube.
8. A gas leak testing device for a gas cylinder, typically a LPG cylinder as claimed in claim 1, as described herein with reference to the accompanying drawings.
9. A method for performing Pin leak test on a gas cylinder, typically a LPG cylinder as claimed in claim 7, as described herein with reference to the accompanying drawings.




21

ABSTRACT
Title: A gas leak testing device for a gas cylinder.
A gas leak testing device for a gas cylinder, typically an LPG cylinder the said device
comprising:
(i) a see through body in which is provided, means for detecting and testing gas leak from the pin of a gas cylinder and means for detecting and testing gas leak from the O-ring of a gas cylinder, alternatively; and
(ii) separate nozzles for locating and removably fitting the said device within the nozzle of a gas cylinder to perform alternatively pin leak test and O-ring leak test.
6 JAN 2006

FORM - 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
PROVISIONAL
Specification
(See section 10 and rule 13)
LEAK TESTER FOR AN LPG CYLINDER
HINDUSTAN PETROLEUM CORPORATION LTD.,
an Indian Company
of Hindustan Bhavan, 3rd Floor, 8, S.V.Marg, Mumbai 400 001,
Maharashtra, India
THE FOLLOWING SPECIFICATION DESCRIBES THE INVENTION.

This invention relates to an apparatus of performing leak test for an LPG cylinder.
In particular, this invention envisages a hand held leak tester for an LPG cylinder performing Pin leak test and O-Ring leak test.
Gas leakage from a cylinder is a one of the major problems encountered in day-to-day life. A precise localized point of such a leakage on the cylinder cannot be pin pointed, but the possibility of leakage through the pin of the cylinder and through the O-ring is the most common. Hence it is necessary to keep a check on such leakage.
The use of sensors for detecting such leakage is a common practice. However sensors using electrical and other electronics circuitry are not preferred for testing leakage of a cylinder, as the slightest spark from such circuitry will prove fatal. Hence a device with no electrical or electronic circuitry is the need of the hour.
In accordance with one practical embodiment of such a device, this invention envisages a hand held leak tester for an LPG cylinder that performs both tests viz (i) Pin Leak Test and (ii) O-Ring Leak Test and is devoid of any electrical or electronic circuitry.
The accompanying drawing, figure 1 is the front view of the leak tester and can be briefly explained as follows
2

The body of the device is made of hard plastic with no electrical or electronic circuitry present. The apparatus is cylindrical in geometry and comprises of two hollow cylindrical tubes placed one inside the other. The outer hollow tube (51) is a single walled tube which forms the body of the of the leak tester as shown in figure 1 of the accompanying drawing. The upper and lower portions of the outer tube (51) are fitted with opaque hard plastic stoppers to form an airtight compartment so as to prevent any kind of leakage. Another hollow tube of smaller diameter is placed inside the outer hollow tube (51), which is the inner tube (52). A concentric capillary tube (56) is placed inside the inner tube (52), which is used for performing the Pin leak test. The lower end of the capillary tube has a small hole (57) through which the gas bubbles out in case of leakage.
Two plastic nozzles are present on the bottom surface of the leak tester. One nozzle is the pin leak testing nozzle (53) and the other is the O- ring leak testing nozzle (54). A water inlet (50) is provided to fill the tubes with water while performing the Pin leak test and the O- ring leak test. A semi cylindrical metal projection (55) is provided with an outlet (58), which acts as the audible indicator in the form of a whistling sound in case of O- ring leak test failure.
The two leak test that are performed using this device are:
1. Pin Leak Test
2. O- Ring Leak test
3

A brief explanation of tests can be given as follows:
1. Pin Leak Test
The pin leak test is designed on the principle of concentric tubes, which uses water as the medium and LPG vapours as bubbles as indicator of the leak. The water level to be maintained in the leak tester is decided based on the sensitivity requirement of the leak tester. The design water level is arrived to maintain the sensitivity inline with the equipments used at plants i.e. 0.5 gms/hr. the sensitivity of the pin tester is 0.5 gms /hi, the maximum test time is 15seconds.
The LPG vapour (leaked) will flow through the inner capillary tube and forces the water inside the inner sleeve, hence the water column in the outer tube moves down to give way to the vapour to escape as bubbles.
2. O- Ring Leak Tester
The O- ring leak tester inlet nozzle is designed to press the valve pin slightly. The LPG vapours escaping through the valve pin is trapped within the inlet nozzle and the O-ring. In case the O- ring is not effective the LPG vapour will pass through the O-ring and then passes into the capillary hole and comes out at the top of the leak tester along with a whistling sound and hence the O- ring leak is indicated.
While considerable emphasis has been placed herein on the structures and structural interrelationships between the component parts of the preferred
4

embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principals of the invention. These and other changes in the preferred embodiment as well as other embodiments of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.
Dated this 26th day of August, 2005.

5

Documents:

1027-mum-2005-abstract (complete).doc

1027-mum-2005-abstract (complete).pdf

1027-MUM-2005-ABSTRACT(6-1-2006).pdf

1027-MUM-2005-ABSTRACT(GRANTED)-(30-6-2011).pdf

1027-mum-2005-cancelled pages(12-6-2009).pdf

1027-MUM-2005-CANCELLED PAGES(14-12-2010).pdf

1027-mum-2005-claims (complete).doc

1027-mum-2005-claims (complete).pdf

1027-MUM-2005-CLAIMS(6-1-2006).pdf

1027-mum-2005-claims(amended)-(12-6-2009).pdf

1027-MUM-2005-CLAIMS(AMENDED)-(14-12-2010).pdf

1027-MUM-2005-CLAIMS(GRANTED)-(30-6-2011).pdf

1027-MUM-2005-CLAIMS(MARKED COPY)-(14-12-2010).pdf

1027-MUM-2005-CORRESPONDENCE(14-12-2010).pdf

1027-mum-2005-correspondence(18-5-2007).pdf

1027-mum-2005-correspondence(ipo)-(31-12-2008).pdf

1027-MUM-2005-CORRESPONDENCE(IPO)-(4-7-2011).pdf

1027-mum-2005-correspondence-received.pdf

1027-mum-2005-description (complete).pdf

1027-mum-2005-description (provisional).pdf

1027-MUM-2005-DESCRIPTION(COMPLETE)-(6-1-2006).pdf

1027-MUM-2005-DESCRIPTION(GRANTED)-(30-6-2011).pdf

1027-MUM-2005-DRAWING(29-8-2005).pdf

1027-MUM-2005-DRAWING(6-1-2006).pdf

1027-MUM-2005-DRAWING(GRANTED)-(30-6-2011).pdf

1027-mum-2005-drawings.pdf

1027-mum-2005-form 18(18-5-2007).pdf

1027-MUM-2005-FORM 2(COMPLETE)-(6-1-2006).pdf

1027-MUM-2005-FORM 2(GRANTED)-(30-6-2011).pdf

1027-MUM-2005-FORM 2(TITLE PAGE)-(COMPLETE)-(6-1-2006).pdf

1027-MUM-2005-FORM 2(TITLE PAGE)-(GRANTED)-(30-6-2011).pdf

1027-MUM-2005-FORM 2(TITLE PAGE)-(PROVISIONAL)-(29-8-2005).pdf

1027-mum-2005-form-1.pdf

1027-mum-2005-form-2 (complete).pdf

1027-mum-2005-form-2 (provisional).doc

1027-mum-2005-form-2 (provisional).pdf

1027-mum-2005-form-26.pdf

1027-mum-2005-form-3.pdf

1027-mum-2005-form-5.pdf

1027-MUM-2005-POWER OF ATTORNEY(14-12-2010).pdf

1027-mum-2005-reply to examination report(12-6-2009).pdf

1027-mum-2005-specification(amanded)-(12-6-2009).pdf

1027-mum-2005-specification(amended)-(12-6-2009).pdf

abstract1.jpg


Patent Number 248274
Indian Patent Application Number 1027/MUM/2005
PG Journal Number 27/2011
Publication Date 08-Jul-2011
Grant Date 30-Jun-2011
Date of Filing 29-Aug-2005
Name of Patentee HINDUSTAN PETROLEUM CORPORATION LTD
Applicant Address HINDUSTAN BHAVAN, 3rd FLOOR, 8, S.V. MARG, MUMBAI-400 001
Inventors:
# Inventor's Name Inventor's Address
1 RAJENDRAN ANUBUCHEZIAN HPCL, LPG BOTTLING PLANT, 171-172 SIDCO INDISTRIAL ESTATE, KAPPALUR MADURAI 625 008
PCT International Classification Number G01M3/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA