ZDDN-II Automatic Kjeldahl Protein Analyzer

The automatic Kjeldahl nitrogen analyzer is a measuring instrument designed based on the principle of the Kjeldahl method. This instrument is also a necessary inspection equipment for QS and HACCP certification in food factories and drinking water factories. Mainly used for the determination of sample nitrogen content and protein.

Working principle:

The Kjeldahl nitrogen analyzer is designed and manufactured on the basis of the international Kjeldahl nitrogen determination method. The main body of this instrument adopts the steam automatic control generator, and with the cooperation of the liquid level regulator, the steam is output stably in tens of seconds. For use in distiller. The lye under the control of the first executive agency flows through the distillation tube into the quantitative digestion tube, so that the ammonia fixed in the acid solution is volatilized under alkaline conditions. The steam under the control of the second executive organ distills the sample under alkaline conditions to completely volatilize the ammonia. The volatilized ammonia is condensed by the condenser, and is completely fixed in boric acid, and then titrated to it with a standard acid. At the end point, calculate the nitrogen content, and then multiply it by the protein conversion coefficient to get the protein content.



1. The automatic Kjeldahl nitrogen analyzer adopts microcomputer for process control, including manual mode and automatic mode, which can be set and switched according to your needs;

     In automatic mode: the whole process of boric acid addition, alkali addition, distillation and ammonia absorption is completed in one time. The volume of boric acid and alkali addition and the time of the distillation and absorption process can be set by themselves.

     In manual mode: the three processes of boric acid addition, alkali addition and distillation absorption can be individually operated manually, and the volume and time can be controlled by themselves to meet the needs of professional users

2. Large screen dot matrix LCD display, full Chinese menu, touch button, simple and convenient operation.
3. Automatic distillation control, automatic water addition, automatic water level control, and automatic water stop.
4. Various safety protections: digestion pipe safety door device, steam generator water shortage alarm, water level detection failure alarm.
5. The maximum number of stored operating programs is 250.
6. The instrument shell is made of special sprayed steel plate, and the working area is made of ABS anti-corrosion panel, which prevents chemical agent corrosion and mechanical damage to the surface, and is acid and alkali resistant.
7. Water level detection, low water level alarm, automatic power off for instrument control system failure.
8. There is no digestion furnace in the standard configuration, but the digestion furnace is optional.

Technical parameters

Determination of varieties grain, feed, food, dairy products, beverages, soil, water, drugs, sediment and chemicals, etc.
Working mode automatic (not including titration)
Water inlet method two inlet methods of tap water and distilled water, which can be used in a wide range of areas
Sample size solid 0.20g~2.00g, semi-fixed 2.00g~5.00g, liquid 10.00ml~25.00ml
Measuring range 0.1mgN~200mgN (mg nitrogen)
Recovery rate  ≥99% (relative error, including digestion process)
Distillation speed 5~15 minutes/sample (according to sample amount)
Cooling water consumption 3L/min
Repetition rate relative standard deviation <±1%
Power supply AC220V/50Hz
Power 1000W
Water supply water temperature is less than 20 degrees
Dimensions 430mm×360mm×670mm
Weight 25kg

Digestion furnaces with different holes are optional (digestion furnace is not included in the standard configuration):

The digital display digestion furnace has 4 holes, 8 holes, 12 holes, and 20 holes to choose from. It takes about 60-90 minutes to digest a batch of samples (depending on the nitrogen content). The SO2 and other harmful gases escaping from the digestive tube are discharged from the water into the sewer through the collection tube through the three-way suction.


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Operation Video

Operation Video