LimsPulse
Petroleum testing

Cloud and Pour Point Apparatus

Cools a fuel or oil in a standard glass test jar through a series of cold baths and examines it at set intervals. The cloud point is where wax crystals first appear; the pour point is the lowest temperature at which the sample still flows.

  • Petroleum refining
  • Lubricant blending
  • Fuel distribution in cold climates
  • Crude oil production and pipelines
  • Independent testing laboratories
Illustration of Cloud and Pour Point Apparatus
Follow your site SOP
This is a typical operating sequence for learning. Your instrument model and approved SOP take precedence.
STAGE 1

Before you start

  1. 1Check that each bath is at its set temperature using the bath thermometers.
  2. 2Check thermometer calibration status and that the mercury or spirit column is unbroken.
  3. 3Dry the sample if it contains water (water freezes and looks like wax).
  4. 4Clean and dry test jars, corks and jackets.
  • Alcohol coolant baths are flammable; keep heat sources away.
STAGE 2

Preparing the sample

  1. 1Cloud point: bring the sample to at least 14 °C above the expected cloud point and filter through dry lint-free paper if needed.
  2. 2Pour point: heat the sample in the jar to the temperature the method specifies (typically 45 °C or more) without stirring vigorously.
  3. 3Fill the jar to the mark and insert the cork and thermometer so the bulb is at the specified position (resting on the bottom for cloud point; just below the surface for pour point).
STAGE 3

Cooling and inspecting

  1. 1Place the jar in its jacket in the first bath; move it to the next colder bath when the sample reaches the method changeover temperature.
  2. 2Cloud: at each 1 °C, remove the jar, look at the bottom for haze and return it within about 3 s.
  3. 3Pour: from 9 °C above the expected pour point, at each 3 °C multiple, tilt the jar just enough to see whether the surface moves; return it within 3 s.
  4. 4Record the cloud point when haze first appears, or the pour point as the no-flow temperature + 3 °C.
  • Handle jars quickly and gently; disturbing the sample breaks the wax structure and gives low pour points.
STAGE 4

After testing

  1. 1Let the jar warm to room temperature before cleaning; do not put a cold jar into hot water.
  2. 2Clean jars with a suitable solvent and dry.
  3. 3Record results with the method, thermometers and bath temperatures used.
  • Cold metal jackets and bath lids can cause cold burns; wear insulated gloves.
In LimsPulse · Calibration Management

Keep every Cloud & pour point tester in control: usage logs, calibration and maintenance schedules, and automatic blocking of overdue instruments.

See how