FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)

1. TITLE OF THE INVENTION:
"A method for checking density of compacted powder in long tubes"
2. APPLICANT:
(a) NAME:
(b) NATIONALITY:
(c) ADDRESS: Larsen & Toubro Limited
Indian Company registered under the provisions of the Companies Act-1956.
Larsen & Toubro Limited L & T House, Ballard Estate, MUMBAI-400001, Maharashtra State, INDIA
3. PREAMBLE TO THE DESCRIPTION:
PROVISIONAL
The following specification describes the invention. COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.

A method for checking density of compacted powder in long tubes
Field of invention
The present invention relates to a method to confirm density of column filled with powder at various cross section of the column for ensuring that minimum specified density is met.
Prior art
There is no method to measure density at various cross section of the tube. Presently only overall average density is derived by taking ratio of weight of powder filled & volume of the filled column.
Steps taken in present method
1. Measure inside height of the tube from bottom face to top edge. Breakup height of the tube into 14 to 16 equal parts.
2. Calculate volume & weight of the powder required to be filled for each part as identified in step 1.
3. Mix the powder with different particle sizes varying from 5 to 6 types as per weight requirement calculated in step 2. Make total of 14 to 16 blends as required. Check & record weight of each blend.
4. Load the tube on Vibro-compaction machine & start the machine with empty tube.
5. Pour first blend of mixture in hooper and set feed rate of supply of powder in tube.
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6. Stop the machine on completion of filling for first blend. Measure balance height of the column of tube & derive filled height & volume of powder filled. Calculate Density based on weight of powder for blend 1 & volume of column filled.
7. Repeat step 5 & 6 for filling balance height of column.
As there is no method to measure density after filling entire tube, density is calculated by filling up known weight of powder, stopping the vibro compacting process for checking volume of filled column & then evaluating density by weight / volume method. The vibro compacting process again starts for filling up balance column height.
Deficiencies of prior art
1. Formation of lower density band due to stoppage of vibro compaction process for density measurement.
2. Density measurement carried out only at local area.
3. Density is measured only during vibro compaction without entire process being completed. Change in density after fully completion of process is not known.
4. Density cannot be measured after closing the pipe, after transportation or at later date.
Object of present invention
Object of the present invention is to provide a method to find density across entire cross section of the column after completion of compaction process to achieve
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minimum density requirement and ensure there are no voids in the vibro-compacted powder.
Summary of the invention
The present invention describes a method for checking density of compacted powder in long tubes. The method comprising steps of preparing five sample block for preparing the container same dimensions, and material. Measuring, the volume of the container and preparing five sample blocks with different densities and calculating the density thereof. Further, conducting, Radiography Test of the blocks using radiographic tester for developing films therefrom for each block (please check/elaborate). Thereafter, establishing relation between density of the samples blocks and optical density of film. Again, performing Radiography Test of the samples block along the entire length and the tube filled with powder. Furthermore, derivating relation between actual density and optical density of RT films.
Statement of the invention
According to the present invention there is provided a method for checking density of compacted powder in long tubes, the method comprising steps of:
preparing five density blocks for sample from five containers, each of the block having height of about 300 mm, made of same material, and having same dimensions;
checking initial empty weight of the containers, thereafter weight the containers with water filled therein;
further, measuring volume of the containers by filling water therein;
preparing five sample blocks having density as 1.70 gm/cc, 1.75 gm/cc, 1.80 gm/cc, 1.85 gm/cc & 1.90 gm/cc;
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further, calculating weight of powder required for each of the densities & fixing volume as calculated for each container, accordingly filling the powder in the five containers;
vibro-compacting the powder in each of the five container and labeling them with respective there densities for preparing blocks having density of as 1.70 gm/cc, 1.75 gm/cc, 1.80 gm/cc, 1.85 gm/cc & 1.90 gm/cc;
carrying out Radiography Test of the blocks using radiographic tester, wherein each block having specific density is exposure to radioactive source, for developing films therefrom for each block (please check/elaborate);
further, reviewing the films for voids, low density bands, and check optical density of the film across known grid location;
establishing relation between density of the samples blocks and optical density of film;
perform Radiography Test of the samples block along the entire length and the tube filled with powder;
compare optical density of film for job and block & derive the density of the job;
methodology for quantification of density in closed containers using above mentioned technique; and
derivating relation between actual density and optical density of RT films.
Description of present invention
The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by the present invention as described below in the preferred embodiment.
The density of the filled powder is achieved by mixing different particle sizes and vibro compaction it in tubes. It is important to achieve overall Density of the powder packed i.e. weight by volume but this does not justify uniformity of density. It is
- 3 NOV 2009

important to maintain uniform density across tube length & ensure there are no voids. Overall density can be calculated by finding the weight of the powder and volume of the tube occupied by powder post filling.
The present invention includes steps of manufacture known density samples blocks, 5 numbers, of about 300 mm height with identical job material & dimensions. Measure volume for each of containers by filling in water, checking initial empty weight of container & final weight of container filled with water.
Further, plan to make 5 samples with varying density as 1.70 gm/cc, 1.75 gm/cc, 1.80 gm/cc, 1.85 gm/cc & 1.90 gm/cc. Calculate weight of the powder required for each of the densities & fixing volume as calculated in step 1.
Further, Vibro-compact the powder in each of the five containers & label them with respective densities.
Carry out RT (Radiography Test) of the blocks. The process involves placement of specific density film on block, exposure to radioactive source, development of film.
Review RT films for voids, low density bands. Check optical density of the film across known grid location.
Establish relation between known density of the samples blocks and optical density of film.
Perform RT of the samples block and the tube filled with powder. Perform multiple RT to cover entire length.
Compare optical density of film for job and block & derive the density of the job.
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The limitations of prior art are overcome by
1. Stoppage machine is avoided as density can be checked post vibro-compaction. Thus, there are no low density bands. Our present technique was used as tool to change the process.
2. As RT can be taken across full length of the tube, density can be evaluated at any point of the tube. Thus, density measurement at local area is overcome.
3. Density is measured only after completion of compaction process. Thus, the data is more accurate than earlier process for which density was measured during compaction process.
4. Present invention can check density at any given time during its entire service period of time.
Advantages
The process is much more reliable and can be conducted at any period of time on any closed filled container. This process can also access damage or any change in interior filled area with out cut opening the tube

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We Claim:
1. A method for checking density of compacted powder in long tubes, the method comprising steps of:
preparing five density blocks for sample from five containers, each of the block having height of about 300 mm, made of same material, and having same dimensions;
checking initial empty weight of the containers, thereafter weight the containers with water filled therein;
further, measuring volume of the containers by filling water therein;
preparing five sample blocks having density as 1.70 gm/cc, 1.75 gm/cc, 1.80 gm/cc, 1.85 gm/cc & 1.90 gm/cc;
further, calculating weight of powder required for each of the densities & fixing volume as calculated for each container, accordingly filling the powder in the five containers;
vibro-compacting the powder in each of the five container and labeling them with respective there densities for preparing blocks having density of as 1.70 gm/cc, 1.75 gm/cc, 1.80 gm/cc, 1.85 gm/cc & 1.90 gm/cc;
carrying out Radiography Test of the blocks using radiographic tester, wherein each block having specific density is exposure to radioactive source, for developing films therefrom for each block (please check/elaborate);
further, reviewing the films for voids, low density bands, and check optical density of the film across known grid location;
establishing relation between density of the samples blocks and optical density of film;
performing Radiography Test of the samples block along the entire length and the tube filled with powder;
compare optical density of film for job and block & derive the density of the job;
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methodology for quantification of density in closed containers using above mentioned technique; and
derivating relation between actual density and optical density of RT films.