Indian Patents. 269181:EXTERNAL SEALING TOOL FOR HYDRAULIC PIPE TESTING

Title of Invention	EXTERNAL SEALING TOOL FOR HYDRAULIC PIPE TESTING
Abstract	The present invention relates to an external sealing tool devised for closing and sealing the ends of pipes subjected to internal pressure comprising of,a housing adapted to fit within the bore,means on the housing for connection to pipe having a passage there through for conveying test medium(water)wherein the housing includes a seal fitted externally to the pipes and a holding plate.

Full Text	2 EXTERNAL SEALING TOOL FOR HYDRAULIC PIPE TESTING FIELD OF INVENTION The present invention relates to a external sealing tool devised as a fastener for closing and sealing pipes wherein ends of pipes subjected to internal pressure, particularly the present invention is used for testing steel pipes, subjected to internal pressure tests in suitable apparatus in which a pipe is filled with water / liquid with a defined temperature and subsequently an increased pressure corresponding to required stresses in the pipe wall is established. BACKGROUND OF THE INVENTION The objective of the present invention lies in the fact that following difficulties were faced while operating the press with internal sealing arrangement which was prevailing since inception of the test apparatus: 1. Internal sealing tools comprised of too many small parts, which made them clumsy and maintenance prone. 2. For same pipe size, there used to be many sets of sealing tools, this was due to the fact that the sealing used to take place on inside diameter, which was depending on the wall thickness of the pipe. 3. Inside of the pipe is generally not so clean compared to the external surface, this was causing damage to the rubber seals, consequence of this was seen in reduced life these seals. 4. Huge inventory of seals and other parts were required because of reasons described above. Above-mentioned difficulties prompted to develop external sealing tools for the testing press. In the ERW pipe plant of Rourkela Steel Plant, pipes of different sizes and grades are produced. Pipes are designated by their outside diameter (OD) and wall thickness. In Rourkela following sizes of pipes are produced: 3 The pipes are produced in lengths of 9 to 12 m. Each pipe thus produced has to undergo a test called hydraulic test in a special testing press made for this purpose. To achieve this, each pipe is brought to the press where they are clamped horizontally between two testing heads called "sealing tools" and high-pressure water is injected into the pipe. Different pressure levels are maintained while testing. This depends upon grade of pipe. After holding the pipe at the desired pressure for a pre-determined time and observing the behavior of pipe under pressure, pressure is released and pipes are certified. Earlier in the original design, pipes are clamped between testing heads, which used to seal the pipes internally and were called "internal sealing tools". Schematic arrangement is shown below in figure-1. SUMMARY OF THE INVENTION Prior to the development of external sealing tools for the testing press in ERW pipe plant, pipe testing used to be a nightmare for production and maintenance engineers for the reasons explained above(refer "background of the invention"). After the invention and successful implementation of external sealing tools, all the difficulties faced earlier have been eliminated. The different objects of the present invention along with advantages are summarized below: It is therefore an object of the present invention is to provide an external sealing tool for testing steel pipes hydraufically in a special tailor made "testing press" having facilities 4 for loading and lowering of pipes to the press and applyingrequired pressure inside the pipe simply, efficiently and inexpensively. It is another object of the present invention is to design external sealing tool which is very simple and comprising of fewer parts. This has made the operation & maintenance friendly. It is another object of the present invention is to design external sealing tool such that only one set is required for each pipe size. It is another object of the present invention is to design external sealing tool wherein the material used is rubber. Because of cleaner outer surface of the pipes, life of rubber seals is increased many folds. Another object of the present invention is to minimize the inventory list which has to be maintained earlier, on account of the above-mentioned reasons. These together with other objects of the invention, along with the various features of novelty, which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated preferred embodiments of the invention. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Fig 1 Relates to the prior art as described in the present specification. Fig 2 shows a schematic arrangement of the external sealing tpol. Fig 3 shows a schematic diagram of external sealing tool (fill side) Fig 4 shows a schematic diagram Details of external sealing tool (vent side) Fig 5 shows enlarged details of seal and associated parts. 5 DETAILED DESCRIPTION Prior to the development of external sealing tools for the testing press in ERW pipe plant, pipe testing used to be a nightmare for production and the maintenance engineers for the aforesaid reasons explained earlier above. After the invention and successful implementation of external sealing tools, all the difficulties faced earlier have been eliminated. BASIC CONSTRUCTIONAL FEATURES: The schematic arrangement of the external sealing tool is shown in figure-2. As explained earlier, external sealing arrangement comprises of two tools namely fill side and vent side. After the pipe is clamped between the tools, fill side is used to fill the pipe with testing medium i.e. water. Function of the vent side is to vent out entrapped air in the pipe. Basic features of both tools are same except for the housings, which are different. Constructional details of fill side and vent side are explained below and shown in Figure-3 & 4 respectively. Fill side: Water is filled in the pipe from this side. See Figure-3. 1 is the housing of fill side tool. This has been reverse engineered to fit into existing press. 2 is the rubber seal which is basically a lip seal specially developed for this purpose. This is held in position by retaining ring 3 and hollow nut 4. This hollow nut also guides the pipe into the sealing tool. Pipe under test is marked 5, which butts against holding plate 6. This holding plate has radial slots, which connect the inside of pipe to the annular space between sea! and retainer ring. When pressure is applied, the seal is inflated and its lips press against outside surface of pipe and inside surface of the housing simultaneously, thus ensuring water tightness. Vent side: The construction details of vent side are shown in Figure-4. The housing is slightly different, as it has to accommodate existing vent valve. Sealing mechanism is exactly same as that of fill side. Figure-5 is enlarged view of the seal and associated 6 parts, which actually ensure water-tightness during hydraulic testing of pipes. Part numbers in Figure-4 & 5 are in consistence with the text described earlier. Following are some of the highlights of the present invention which impress upon the different advantages of the invention on adoption at ERW pipe plant of Rourkela Steel Plant. Use of external sealing tool in the testing press of ERW pipe plant has brought the following advantages: 1. Use of very few components has rendered this device operation and maintenance friendly. 2. Seal life has gone up to almost twenty folds compared to the early system of internal sealing. 3. As the external sealing tools are not dependent on the wall thickness of pipes-being tested, productivity of the press has increased by elimination of changeover time, which was required earlier. 4. Inventory has been brought down to minimum. 5. Considerable cost reduction on account of testing of pipes has been achieved which in turn has increased profitability. 6. These tools have been designed, manufactured and tested for all pipe sizes. The above-described embodiments of the invention are intended to be examples of the present invention. Numerous modifications changes and improvements within the scope of the invention will occur to the reader. Those of skill in the art may effect alterations and modifications thereto, without departing from the scope of the invention, which is defined solely by the claims appended hereto. 7 We Claim: 1. An external sealing tool devised for closing and sealing the ends of pipes subjected to internal pressure comprising of, a housing adapted to fit within the bore, means on the housing for connection to pipe having a passage there through for conveying test medium (water) wherein the housing includes a seal fitted externally to the pipes and a holding plate. 2. The external sealing tool as claimed in claim 1, wherein the housing includes a retaining ring and hollow nut. 3. The external sealing tool as claimed in claim 2, wherein the hollow nut also guides the pipe into the sealing tool. 4. The external sealing tool as claimed in claim 1, wherein the seal is a lip seal specially developed for this purpose made up of rubber. 5. The external sealing tool as claimed in claim 1, wherein the holding plate has radial slots, which connect the inside of pipe to the annular space between seal and retainer ring. 6. The external sealing tool as claimed in claim 4, wherein the seal is effected by application of hydraulic pressure. 7. An apparatus for testing the sealing of a joint between hollow members, comprising external sealing tool as claimed in any of the preceding claims. To, The Controller of Patents, The Patent Office, Kolkata. The present invention relates to an external sealing tool devised for closing and sealing the ends of pipes subjected to internal pressure comprising of,a housing adapted to fit within the bore,means on the housing for connection to pipe having a passage there through for conveying test medium(water)wherein the housing includes a seal fitted externally to the pipes and a holding plate.

Full Text

2
EXTERNAL SEALING TOOL FOR HYDRAULIC PIPE TESTING
FIELD OF INVENTION
The present invention relates to a external sealing tool devised as a fastener for closing and sealing pipes wherein ends of pipes subjected to internal pressure, particularly the present invention is used for testing steel pipes, subjected to internal pressure tests in suitable apparatus in which a pipe is filled with water / liquid with a defined temperature and subsequently an increased pressure corresponding to required stresses in the pipe wall is established.
BACKGROUND OF THE INVENTION
The objective of the present invention lies in the fact that following difficulties were faced while operating the press with internal sealing arrangement which was prevailing since inception of the test apparatus:
1. Internal sealing tools comprised of too many small parts, which made
them clumsy and maintenance prone.
2. For same pipe size, there used to be many sets of sealing tools, this was
due to the fact that the sealing used to take place on inside diameter,
which was depending on the wall thickness of the pipe.
3. Inside of the pipe is generally not so clean compared to the external
surface, this was causing damage to the rubber seals, consequence of
this was seen in reduced life these seals.
4. Huge inventory of seals and other parts were required because of
reasons described above.
Above-mentioned difficulties prompted to develop external sealing tools for the testing press.
In the ERW pipe plant of Rourkela Steel Plant, pipes of different sizes and grades are produced. Pipes are designated by their outside diameter (OD) and wall thickness. In Rourkela following sizes of pipes are produced:

3

The pipes are produced in lengths of 9 to 12 m. Each pipe thus produced has to undergo a test called hydraulic test in a special testing press made for this purpose. To achieve this, each pipe is brought to the press where they are clamped horizontally between two testing heads called "sealing tools" and high-pressure water is injected into the pipe. Different pressure levels are maintained while testing. This depends upon grade of pipe. After holding the pipe at the desired pressure for a pre-determined time and observing the behavior of pipe under pressure, pressure is released and pipes are certified.
Earlier in the original design, pipes are clamped between testing heads, which used to seal the pipes internally and were called "internal sealing tools". Schematic arrangement is shown below in figure-1.
SUMMARY OF THE INVENTION
Prior to the development of external sealing tools for the testing press in ERW pipe plant, pipe testing used to be a nightmare for production and maintenance engineers for the reasons explained above(refer "background of the invention"). After the invention and successful implementation of external sealing tools, all the difficulties faced earlier have been eliminated. The different objects of the present invention along with advantages are summarized below:
It is therefore an object of the present invention is to provide an external sealing tool for testing steel pipes hydraufically in a special tailor made "testing press" having facilities

4
for loading and lowering of pipes to the press and applyingrequired pressure inside the pipe simply, efficiently and inexpensively.
It is another object of the present invention is to design external sealing tool which is very simple and comprising of fewer parts. This has made the operation & maintenance friendly.
It is another object of the present invention is to design external sealing tool such that only one set is required for each pipe size.
It is another object of the present invention is to design external sealing tool wherein the material used is rubber. Because of cleaner outer surface of the pipes, life of rubber seals is increased many folds.
Another object of the present invention is to minimize the inventory list which has to be maintained earlier, on account of the above-mentioned reasons.
These together with other objects of the invention, along with the various features of novelty, which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig 1 Relates to the prior art as described in the present specification.
Fig 2 shows a schematic arrangement of the external sealing tpol.
Fig 3 shows a schematic diagram of external sealing tool (fill side)
Fig 4 shows a schematic diagram Details of external sealing tool (vent side)
Fig 5 shows enlarged details of seal and associated parts.

5
DETAILED DESCRIPTION
Prior to the development of external sealing tools for the testing press in ERW pipe plant, pipe testing used to be a nightmare for production and the maintenance engineers for the aforesaid reasons explained earlier above. After the invention and successful implementation of external sealing tools, all the difficulties faced earlier have been eliminated.
BASIC CONSTRUCTIONAL FEATURES:
The schematic arrangement of the external sealing tool is shown in figure-2.
As explained earlier, external sealing arrangement comprises of two tools namely fill side and vent side. After the pipe is clamped between the tools, fill side is used to fill the pipe with testing medium i.e. water. Function of the vent side is to vent out entrapped air in the pipe. Basic features of both tools are same except for the housings, which are different. Constructional details of fill side and vent side are explained below and shown in Figure-3 & 4 respectively.
Fill side: Water is filled in the pipe from this side. See Figure-3. 1 is the housing of fill side tool. This has been reverse engineered to fit into existing press. 2 is the rubber seal which is basically a lip seal specially developed for this purpose. This is held in position by retaining ring 3 and hollow nut 4. This hollow nut also guides the pipe into the sealing tool.
Pipe under test is marked 5, which butts against holding plate 6. This holding plate has radial slots, which connect the inside of pipe to the annular space between sea! and retainer ring. When pressure is applied, the seal is inflated and its lips press against outside surface of pipe and inside surface of the housing simultaneously, thus ensuring water tightness.
Vent side: The construction details of vent side are shown in Figure-4. The housing is slightly different, as it has to accommodate existing vent valve. Sealing mechanism is exactly same as that of fill side. Figure-5 is enlarged view of the seal and associated

6
parts, which actually ensure water-tightness during hydraulic testing of pipes. Part numbers in Figure-4 & 5 are in consistence with the text described earlier.
Following are some of the highlights of the present invention which impress upon the different advantages of the invention on adoption at ERW pipe plant of Rourkela Steel Plant.
Use of external sealing tool in the testing press of ERW pipe plant has brought the following advantages:
1. Use of very few components has rendered this device operation and maintenance
friendly.
2. Seal life has gone up to almost twenty folds compared to the early system of internal
sealing.
3. As the external sealing tools are not dependent on the wall thickness of pipes-being
tested, productivity of the press has increased by elimination of changeover time, which
was required earlier.
4. Inventory has been brought down to minimum.
5. Considerable cost reduction on account of testing of pipes has been achieved which
in turn has increased profitability.
6. These tools have been designed, manufactured and tested for all pipe sizes.
The above-described embodiments of the invention are intended to be examples of the present invention. Numerous modifications changes and improvements within the scope of the invention will occur to the reader. Those of skill in the art may effect alterations and modifications thereto, without departing from the scope of the invention, which is defined solely by the claims appended hereto.

7
We Claim:
1. An external sealing tool devised for closing and sealing the ends of pipes subjected
to internal pressure comprising of, a housing adapted to fit within the bore, means on the
housing for connection to pipe having a passage there through for conveying test
medium (water) wherein the housing includes a seal fitted externally to the pipes and a
holding plate.
2. The external sealing tool as claimed in claim 1, wherein the housing includes a
retaining ring and hollow nut.
3. The external sealing tool as claimed in claim 2, wherein the hollow nut also
guides the pipe into the sealing tool.
4. The external sealing tool as claimed in claim 1, wherein the seal is a lip seal
specially developed for this purpose made up of rubber.
5. The external sealing tool as claimed in claim 1, wherein the holding plate has
radial slots, which connect the inside of pipe to the annular space between seal and
retainer ring.
6. The external sealing tool as claimed in claim 4, wherein the seal is effected by
application of hydraulic pressure.
7. An apparatus for testing the sealing of a joint between hollow members,
comprising external sealing tool as claimed in any of the preceding claims.

To,
The Controller of Patents, The Patent Office, Kolkata.
The present invention relates to an external sealing tool devised for closing and sealing the ends of pipes subjected to internal pressure comprising of,a housing adapted to fit within the bore,means on the housing for connection to pipe having a passage there through for conveying test medium(water)wherein the housing includes a seal fitted externally to the pipes and a holding plate.

Documents:

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Patent Number

269181

Indian Patent Application Number

1093/KOL/2006

PG Journal Number

41/2015

Publication Date

09-Oct-2015

Grant Date

07-Oct-2015

Date of Filing

18-Oct-2006

Name of Patentee

Steel Authority of India Limited

Applicant Address

Rourkela Steel Plant,Rourkela-769011

Inventors:

#	Inventor's Name	Inventor's Address
1	APARUP BHATTACHARYA	Rourkela Steel Plant,Rourkela-769011

PCT International Classification Number

E04B 1/68

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA