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Bulletin No. 46 |
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Chemical |
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CONSTANT CENTER DIFFERENTIAL GRAVITY APPARATUS |
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The information that follows is based on the use of our water based liquids, Sodium Polytungstate (S/P), Lithium Metatungstate (LMT) and LST. The Constant Center Differential Gravity Tube Apparatus is used for very rapid routine repetitive mineral density determinations. Oil Well Loggers do this in their Shale density determinations on the constant look out for shale porosity and open determinations. The method and apparatus is applicable to many other routine density determinations. A Differential Gravity tube is set up in our apparatus according to the method described in our Bulletin No. 40. With this apparatus, the user may keep his working gravity area in the same place relative to constant scale markings outside the tube. In this manner any porous shale or other off density mineral under routine examination is immediately spotted. Using our water based products can be simple and easy. The method is similar to the chemical based apparatus as described in Bulletin No. 45. In using any one of our water based heavy liquids: example: Sodium Polytungstate (S/P), Lithium Metatungstate (LMT), LST. Sodium Polytungstate is our most popular water based product. General Concept: |
Assemble the apparatus according to the picture. Set leveling bulb, shown at the right, opposite the 25 ml. mark on the burette and add thru the bulb until it is up to the 25 ml. mark. Then add distilled water thru the top of the burette
until the burette is full. Now lower the leveling bulb so
that the liquid, liquid interface is opposite the 50 ml.
mark and add more distilled water to the zero mark or above
into the burette. Generate your differential gravity zone
within the burette according to Bulletin No. 40. After a
proper gradient is established, put in your 11 bead density
set. Put in several Shales (or minerals) of known porosity
or density and check their density from the tube. As you get
to working with your Shales (or minerals) you will get to
know the best minimum and maximum densities for your own
work and mark lines on the glazed paper attached to the
burette according to your own needs. Green and Red limiting
marks at either end of the areas are good reminders in
routine work. Each day or any other convenient time, the glass standard at 2.48 can be lined up at the 50 ml. mark and the locations of the High and Low Shale samples may be noted if they have changed appreciably from your previous settings. When the tube gets very many Shale (or mineral) samples in it, they may be flushed out through the top of the burette by tilting it over a beaker or can and raising the lower leveler to flush the samples out. Replace the burette and leveling bulb on the stand, add distilled water into the top of the burette as before and generate a new differential gravity tube. Recover your standards and marker Shales (or minerals) and put them back into the new tube. Each tube generation lasts about a month in routine work.
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