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Vilitek PMP-8 digester (mineralization chamber) for Kjeldahl protein analysis

Vilitek PMP-8 digester is designed for samples mineralization during protein or nitrogen content analysis by the Kjeldahl method in Vilitek AKV-20, AKV-21, AKV-30, AKV-31, AKV-32 Kjeldahl automatic apparatuses. Besides, digester can be used as a thermal reactor (heating unit) for chemical oxygen demand (COD) water analysis.

Vilitek PMP-8 digesterThere are several different standards for various products that determine the procedure of Kjeldahl protein analysis; according to these standards, different names can be used for devices with identical functions. Digesters are used in the process of mineralization of samples dissolved in sulfuric acid by heating them in a catalyst. In particular, there are the following definitions of digesters: “electric heaters or gas burners that make it possible to maintain temperatures from +450 °C to +500 °C”, “aluminum block with sockets for test tubes or Kjeldahl flasks”. In any case, the function of this device is relatively simple — it heats Kjeldahl flasks with the product samples, sulfuric acid, catalyst and elements that prevent spraying during boiling, for example, with glass balls. Obviously, at the present stage of laboratory equipment development, the use of standard stoves or, especially, gas burners to heat Kjeldahl flasks is absolutely unacceptable, since the laboratory assistant conducting this procedure is forced to inhale dangerous fumes of sulfuric acid. PMP-8 digesters allow group processing of samples with reliable fixation of flasks and removal of fumes, and in addition they minimize the time of mineralization due to rapid heating and the ability to work at the upper limit of the temperature range specified by the standards.

Vilitek PMP digester (mineralization chamber) for Kjeldahl protein analysis

Features and advantages of PMP-8 digesters:

  • high-quality heating unit is made of aluminium alloy and equipped with a chromel heating element, which provides excellent uniformity and accuracy of heating, resistance to acids and alkalis, as well as a long service life;
  • continuously adjustable temperature of heating unit increases the ease and flexibility of apparatus operation;
  • high rate of temperature increase saves the time required to prepare samples for Kjeldahl analysis;
  • high thermal efficiency;
  • robust powder-coated steel casing which upper working surface is made of stainless steel without painting;
  • reliable double thermal insulation of casing provides apparatus high safety;
  • built-in protection against power surges and overheating;
  • device is very simple to operate, switching on/off with one button;
  • scope of supply includes Kjeldahl flasks according to the number of sockets in digester (8 pcs.).
  • scope of supply includes an exhaust.

PMP-8 digesters are equipped with an aluminium heating unit with sockets for Kjeldahl flasks for sample fast accurate and uniform heating. Temperature is maintained by temperature controller with an intelligent PID algorithm to avoid flasks overheating. Any temperature (from room temperature to maximum) can be set.

The PMP-8 digestors are supplied with a collector to remove fumes, it is connected to a water-jet pump or scrubber based at chemically-resistant SKB-4 vacuum pump (to be purchased separately). Since sample mineralization is carried out in a boiling sulfuric acid medium, despite the use of a collector for exhaust gases and a scrubber, in any case, the digester should only be installed inside exhaust hood.

SKB-4 gas waste system
SKB-4 gas waste system

The scrubber to remove gases is a high-quality laboratory Chemker 300 membrane vacuum pump with alkali containers through which exhaust gases are pumped off. The pump works completely without lubricants or other liquids in the working chamber, and does not require maintenance. The flow part is completely made of polytetrafluoroethylene, which provides unrivalled chemical resistance and durability.

A set of 300 ml Kjeldahl flasks that correspond to international standards are supplied with PMP-8 digesters, as well as collectors to remove fumes; number of flasks are in accordance with the number of digester sockets. Collectors and flasks are made of special chemically and heat-resistant glass. In addition, the base package includes a holder with handles for Kjeldahl flasks, which is used to carry the flasks and fix them on the digester, as well as a rack for the flasks on which they can be placed before or after processing in the digester, for example, for cooling.



Number of Kjeldahl flask sockets, pcs

Accuracy of temperature control, °C

Max. heating rate, °С

Max. temperature, °С

Power, W

Overall dimensions, mm

Weight, kg










  • Gas disposal and aftertreatment system based at Vilitek membrane chemically-resistant SKB-4 vacuum pump
  • Additional Kjeldahl flask
  • Additional flask rack for PMP-8