The advantage of automatic Kjeldahl determination of the content of volatile acid in wine

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Volatile acids have a serious impact on the brewing quality of wine. Its main composition consists of two parts, some of which are produced by alcoholic fermentation. This part is normally present, and part of it is produced by bacterial infestation and belongs to heterogeneous species. It is generally between 0.4^-0.7g/L. If the volatile acid content in the wine exceeds 0.8 g/L, it will occupy the main taste of the grapes and suppress the taste characteristics of the wine. Therefore, its content is an important indicator of wine quality control. For this reason, it is of great significance to develop an accurate and rapid method for determining the volatile acid content of wine.

Automatic Kjeldahl instrument is commonly used in various types of testing laboratories. It is mainly used for nitrogen content testing in materials, foods, feeds, etc. The degree of automation of the instrument is high, and the precision and accuracy of the results are compared. it is good. In this paper, the method of fast and accurate determination of volatile acid content in wine was developed for the first time using an automatic Kjeldahl nitrogen analyzer. The method was applied to the determination of volatile acid content in real samples of wine and satisfactory results were obtained.

The measured sample needs to be sampled by distillation before it can be measured by the automatic Kjeldahl tester. The volatile acid in wine was determined under the best distillation conditions. Compared with the national standard method, it can be seen that the determination of volatile acid content in wine was performed using an automatic Kjeldahl determination instrument. The relative standard deviation was 0.1700, and the recovery was in the range of 93.000^99.3%.

For the use of automatic Kjeldahl determination of the content of volatile acids in wine has many advantages, first of all, the steam generated by the built-in steam packets, steam flow is stable, volatile acid steamed out, the determination of the results of good precision. Secondly, the automatic Kjeldahl nitrogen analyzer uses an automatic titrator with a minimum titration volume of 0.005 mL, resulting in good precision and accuracy. Finally, the automatic Kjeldahl meter uses the principle of potentiometric titration. The jump at the point of measurement and the end of the titration are controlled by the instrument. The error is small and the accuracy is high. In short, the use of automatic Kjeldahl determination of volatile acid content in wine has the advantages of simple, fast and accurate operation. The actual sample determination results show that this method can fully meet the needs of wine enterprises in production control and food safety quality control.

"Gravity Die Casting. A permanent mould casting process, where the molten metal is poured from a vessle of ladle into the mould, and cavity fills with no force other than gravity, in a similar manner to the production of sand castings, although filling cn be controlled by tilting the die."

Gravity Die Casting

Sometimes referred to as Permanent Mould, GDC is a repeatable casting process used for non-ferrous alloy parts, typically aluminium, Zinc and Copper Base alloys.

The process differs from HPDC in that Gravity- rather than high pressure- is used to fill the mould with the liquid alloy.

GDC is suited to medium to high volumes products and typically parts are of a heavier sections than HPDC, but thinner sections than sand casting.

There are three key stages in the process.

  1. The heated mould [Die or Tool] is coated with a die release agent. The release agent spray also has a secondary function in that it aids cooling of the mould face after the previous part has been removed from the die.
  2. Molten metal is poured into channels in the tool to allow the material to fill all the extremities of the mould cavity. The metal is either hand poured using steel ladles or dosed using mechanical methods. Typically, there is a mould [down sprue" that allows the alloy to enter the mould cavity from the lower part of the die, reducing the formation of turbulence and subsequent porosity and inclusions in the finished part.
  3. Once the part has cooled sufficiently, the die is opened, either manually or utilising mechanical methods.

Advantages

  • Good dimensional accuracy
  • Smoother cast surface finish than sand casting
  • Improved mechanical properties compared to sand casting
  • Thinner walls can be cast compared to sand casting
  • Reverse draft internal pockets and forms can be cast in using preformed sand core inserts
  • Steel pins and inserts can be cast in to the part
  • Faster production times compared to other processes.
  • Once the tolling is proven, the product quality is very repeatable.
  • Outsourced Tooling setup costs can be lower than sand casting.

Gravity Casting Parts

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