BD-46 Block Digestors Series
Increase accuracy, precision and productivity with the BD-46 from Lachat Instruments.
Developed to perform high temperature digestions to determine total Kjeldahl nitrogen and total phosphorus
in environmental samples, the BD-46 brings several important innovations to this well-accepted block digestion
technique including:
• 46 x 75 mL tube positions
• Expansion bulb built into tube design to reduce foaming
• Cold fingers to condense fumes
• Integral programmable controller for increased safety and convenience
• UL-listed for safety and design quality
• C-tick marked in Australia
• Not CE marked
• Expansion bulb built into tube design to reduce foaming
• Cold fingers to condense fumes
• Integral programmable controller for increased safety and convenience
• UL-listed for safety and design quality
• C-tick marked in Australia
• Not CE marked
Ordering Information on Hach.com 
Maximize Accuracy and Precision
Because the BD-46 has 46 tube positions rather than the usual 40, calibration standards can now be carried through the same digestion process as the samples. This maximizes accuracy and precision since the standards and sample are treated exactly the same.
Because the BD-46 has 46 tube positions rather than the usual 40, calibration standards can now be carried through the same digestion process as the samples. This maximizes accuracy and precision since the standards and sample are treated exactly the same.
Reduce Overflow of Samples with Surfactants
Many wastewater samples contain varying levels of surfactants which will cause foaming of the sample during digestion. The foam may then overflow from the tube onto the heated block. The special design of the BD-46 digestion tube incorporates a bulb toward the top which breaks up most foams and reduces overflow.
Many wastewater samples contain varying levels of surfactants which will cause foaming of the sample during digestion. The foam may then overflow from the tube onto the heated block. The special design of the BD-46 digestion tube incorporates a bulb toward the top which breaks up most foams and reduces overflow.
Increased Reliability and Viewability of Controller
The BD-46 programmable controller is attached to the block on a flexible arm which keeps it high and dry, away from spillage, and makes it easily adjustable to vary viewing angles. Other block digestors have controllers separated from the block and sit on the bench where they are liable to spillage and are difficult to view.
The BD-46 programmable controller is attached to the block on a flexible arm which keeps it high and dry, away from spillage, and makes it easily adjustable to vary viewing angles. Other block digestors have controllers separated from the block and sit on the bench where they are liable to spillage and are difficult to view.
Eliminates the Need for Expensive Acid Scrubbers
Until the BD-46, acid fumes have presented a serious problem. Either an expensive and often ineffective acid scrubber needed to be purchased or the unit needed to be placed in a hood where corrosive fumes would attack the seals and significantly shorten the life of the hood. Now, with the addition of an inexpensive glass cold finger to each digestion tube, the acid fumes are cooled, condensed and returned to the the tube where they belong. Recovery of acid fumes is nearly 100% for 2 hours of refluxing. The following table shows complete recovery of sulfuric acid across the block.
Until the BD-46, acid fumes have presented a serious problem. Either an expensive and often ineffective acid scrubber needed to be purchased or the unit needed to be placed in a hood where corrosive fumes would attack the seals and significantly shorten the life of the hood. Now, with the addition of an inexpensive glass cold finger to each digestion tube, the acid fumes are cooled, condensed and returned to the the tube where they belong. Recovery of acid fumes is nearly 100% for 2 hours of refluxing. The following table shows complete recovery of sulfuric acid across the block.
| Tube Row | % acid (v/v) | std. dev. | % rsd | % recovery |
| 1 (front) | 4.80 | 0.02 | 0.41 | 99.0 |
| 2 | 4.80 | 0.01 | 0.28 | 99.0 |
| 3 | 4.82 | 0.01 | 0.25 | 99.4 |
| 4 (rear) | 4.79 | 0.01 | 0.25 | 98.8 |
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