T08 Sprayability Test Rig

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The sprayability rig in the Tribology Lab

Documentation

Test Procedure

Download the Grease Sprayability Test Procedure

The sprayability test rig consists of the following elements:

  • A single-plunger grease pump, type Delimon FZ-B;
  • A standard Delimon type FZ-B progressive lubricant distributor serving 6 120° flat spray nozzles;
  • A logic circuit controlling the timing sequence of the spray system; and
  • An air pressure regulator.

The nozzles are spaced equidistant at 160 mm intervals so as to ensure no overlap between spray patterns of individual nozzles. The nozzles spray against a sheet of clear Mylar which is placed perpendicular to the spray direction and at a distance of 150 mm from the nozzles. Four complete spray bursts of 7 seconds duration each are collected on the Mylar sheet, after which the sheet is removed and photographed. (In most cases only one spray burst is necessary).

Each spraying cycle delivers 0,2 cubic centimeters of lubricant per nozzle. The delivery air pressure is maintained at 200, 300 and 500 kPa. The test is performed at ambient temperature.

A modified spray test is also performed at below ambient temperatures. The test is conducted in the following manner:

A grease gun is filled with the grease to be tested and placed in a refrigerator to reach the required temperature: -5 or 0°C. The grease gun is attached to the distribution block of the Delimon apparatus described above. The same number of bursts is sprayed onto a Mylar sheet through one spray nozzle

Visual analysis of the spray pattern leads to a grading on a scale of 1 to 5:

  1. Excellent
  2. Very good
  3. Acceptable
  4. Below average
  5. Poor

The properties evaluated are: Spray pattern, Area coverage of lubricant, Distribution of particles, Form of particles, Size of sprayed particles.