Cloud point

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Logo of the German Institute for Standardization DIN EN 23015
Area Petroleum products
title Petroleum products; Determination of the cloud point
Latest edition 5.1994

The term cloud point ( CP ; English: cloud point ) denotes a cold property of diesel fuel and heating oil . It refers to the temperature in degrees Celsius , at which a bare liquid product under test conditions defined by the formation of paraffin crystals hazy or cloudy is ( Tyndall effect ). According to DIN 51603-1, the cloud point for extra-light heating oil may be a maximum of 3 ° C. In the case of diesel fuel, the cloud point is not specified according to EN 590 . Brand manufacturers, however, have an internal specification that - depending on the season - ranges from +5 ° C to −9 ° C (for an explanation, see filterability limit (cold filter plugging point)) .

The cloud point alone is not meaningful for the usability of heating oil at low temperatures, as the cloudiness initially has no effect on its usability. Only the combination of the cloud point and the filterability limit, the temperature at which a test filter clogs, is decisive for assessing the low-temperature properties.

A similar method for kerosene is below freezing (ger .: Freezing Point described (ISO 3013)).

The cloud point is determined in accordance with EN 23015.

Definition of terms

The cloud point is often referred to as the cloud point. This collides with the so-called turbidity point according to ASTM D 4176, which characterizes the behavior of the dissolved water in the mixture. The term crystallization point collides with DIN 51798 (benzene "freezing point"), or with DIN 51782 (coolant / refrigeration technology). In addition, “crystallization point” is also - incorrectly - used synonymously for freezing point in some sources. The DIN standard speaks of "cloud point".

Individual evidence

  1. ^ Fuel Quality Testing
  2. Finke definitions  ( page no longer available , search in web archivesInfo: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.@1@ 2Template: Toter Link /  
  3. Refrigeration technology .
  4. Example: Dr. Hartmut Behr: aviation fuels and their future: AVGAS, MOGAS, Jet A-1, diesel fuel (PDF): . Retrieved July 5, 2012.