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Temco Tech Tips

Sampling Tips

 1. SAMPLING HARDWARE

Typical sample tap should be 1" to 1 ½ " in diameter. Special sample taps are sold. However, any sample tap and valve should meet five conditions:
  • 1. The Sample Valve should be located as close to the transmitter as possible.
  • 2. The Sample Valve must extend into the process line beyond the pipe wall. The ideal is 1/3 of the pipe diameter.
  • 3. The sample tap inlet should be cut off parallel with the stock flow.
  • 4. The tap should be in a turbulent, well-agitated section of the process line near the transmitter.
  • 5. The sample line must be able to throttled without plugging. The sample flow must be slow enough to be collected in the sample container without splashing.
  • 6. The sample valve must shut off tight.

Sampling system
Ultimate sampler
2. SAMPLING PROCEDURE { System Should be in Automatic Control }
  • 1) Verify that the transmitter is holding the set point and that there are no upsets occurring at the time the sample is taken.
  • 2) Record the transmitter's consistency output and the time the sample is taken.
  • 3) Use a clean and dry 10-Liter bucket.
  • 4) Open the sample valve and establish a reasonable flow rate for several seconds. Old stock must be allowed to clear the line. Pipe length will determine this purge time.
  • 5) Direct the full stream into the 10-Liter bucket until the bucket is filled between the 6 and 7 liter lines.

3. SAMPLE PROCESSING
Sampling Processing Choice # 1
  • 1) Use three clean and dry containers and three dry filter pads.
  • 2) Record the tare weight of each container and each filter pad.
  • 3) Stir the sample in the 10-liter bucket for 1 minute, and take the first sample. The sample should be 200ml to 300ml.
  • 4) Stir the sample in the 10-liter bucket for 1 minute, and take the second sample. The sample should be 200ml to 300ml.
  • 5) Stir the sample in the 10-liter bucket for 1 minute, and take the third sample. The sample should be 200ml to 300ml.
  • 6) Record the weight of each wet sample, and then process the sample onto the filter pads.
  • 7) Heat the sample pads until the weight no longer changes.
  • 8) Subtract the tare weight from the sample pad to obtain dry sample.
i.e. Dry Sample pad - pad's tare weight = Dry Sample
  • 9) Subtract the tare weight from the container sample to obtain wet sample.
i.e. Container sample - container's tare weight = Wet Sample
  • 10) Divide the dry sample by the wet sample and multiply by 100 to obtain the sample consistency.
i.e. Dry Sample / Wet Sample x 100 = Sample Consistency Calculate your results to two decimal places.
  • 11) Repeat steps 8 - 10 for each sample
  • 12) Calculate the average of the three samples. This is your Consistency Reading.
  • 13) Subtract your lowest sample from your highest sample. This is your Range.
· The sample procedure should be performed in the mill's lab.
· Be sure to get all the numbers used for the consistency determination.
This should include: Weight of the initial sample Tare weight of the container Tare weight of the filter pad Dried sample weight
Sampling Processing Choice # 2 - (A compromise between accuracy and time )
  • 1) Use one clean and dry 100ml exact container and three dry filter pads.
  • 2) Record the tare weight of each filter pad and use the same 100ml container for each sample. Assume the 100ml volume weights 100grams.
  • 3) Stir the sample in the 10-liter bucket for 1 minute, and take the first sample. Insert the 100ml container into the bucket. Use the container to stir the bucket for an additional 10 seconds. Then pull the 100ml straight out of the bucket then remove additional stock from the top and sides of the 100ml container.
  • 4) Process the sample onto the filter pads.
  • 5) Heat the sample pads until the weight no longer changes.
  • 6) Subtract the tare weight from the sample pad to obtain dry sample. This number is your consistency reading for this pad.
  • 7) Repeat steps 3 - 6 for the additional three samples.
  • 8) For Consistency Reading, Calculate the average of the four samples.
  • 9) For Range, Subtract your lowest sample from your highest sample.
    · The sample procedure should be performed in the mill's lab.
    · Be sure to get all the numbers used for the consistency determination.
This should include: Weight of the initial sample Tare weight of the filter pad Dried sample weight

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