Resolver Test Method

This is the recommended method for the determination of the Particulate and Free‐water content of Middle Distillate Fuels (e.g. Aviation Turbine & Automotive Diesel Fuels) using an Automatic Particle Counter and ResolverTM.

Scope

 

This paper describes the use of an automatic particle counter (APC) for determining the level of dispersed contamination in middle distillate fuel, specifically dirt particles and water droplets in the range from 4 μm(C) to ~200 μm(C).

 

By using ResolverTM, total (dirt particles and water droplets) and corrected (dirt particles only) counts are produced. A differential count between total and corrected can be used to estimate the level of dispersed free‐water.

 

NOTE 1: The subscript (C) is used to denote that the calibration of the apparatus is traceable to ISO 11171:1999.

NOTE 2: An automatic particle counter uses a light obscuration principle in which the area of the shadow cast by the particle is converted into the diameter of its equivalent sphere.

Principle

 

The following scheme describes the overall analytical process:

 

An original sample of minimum volume 1 litre, is divided into two ~500 cm3 portions contained in clean or flushed sample bottles of volume sufficient to include ~10% ullage space.

 

ResolverTM is added to one of the sub‐samples (B) and both sample bottles are stoppered. The untreated sample (A) is prepared for analysis by turning end‐over‐end for 1 minute and then analysed. On completion of the analysis of sample A, sample B is then turned end‐over‐end for 1 minute and then analysed.

Apparati

 

Suitable Automatic Particle Counter instruments are used in Energy Institute Test methods IP564, IP565 and IP577 and calibrated by the manufacturer in accordance with ISO 11171:1999.

 

Test portion container of minimum volume 1 litre, with either a non‐shedding threaded cap forming a seal with the container without the use of an insert, or a cap with a suitable internal seal.

 

Sub‐sample containers of minimum volume 0.5 litre with either a non‐shedding threaded cap forming a seal with the container without the use of an insert, or a cap with a suitable internal seal.

 

Waste container, for collecting the tested sample.

Procedure

 

  1. Homogenise the original sample for a minimum of 1 minute. This could involve turning end‐over end manually if the sample container is conveniently sized or rolling if large.
  2. Pour approximately 450 cm3 into each of the sub‐sample containers marked Sample A and Sample B.
  3. Add the contents of the ResolverTM vial (10 cm3) to Sample B.
  4. Seal or stopper both Samples A and B and commence end‐over‐end tumbling of Sample A for 1 minute.
  5. Analyse Sample A using the appropriate method for the APC in use.
  6. Commence end‐over‐end tumbling of Sample B for 1 minute.
  7. Analyse Sample B using the appropriate method for the APC in use.
  8. Collate both sets of results.

 

Note: The use of graduated bottles will facilitate the pouring of liquid volumes required in Samples A and B. Alternatively non‐graduated bottles may be used but the operator will have to mark the relevant volume levels manually on the outside of the sample bottle using tape or marker pen.

Reporting results

 

  1. Report the average of the three recorded results e.g.: For Jet Turbine Fuels ‐ Cumulative channel particle counts, >4μm(C), >6μm(C), >14μm(C), >21μm(C), >25μm(C) & >30μm(C) (number of particles shall be quoted per millilitre of sample).
  2. Cleanliness coding according to ISO 4406:1999.

Expression of results

 

The test report should include:

  1. The type and complete identification of the product tested;
  2. The date and time of the test;
  3. The results of the tests on Sample A and Sample B in separate columns;
  4. Any deviation by agreement or otherwise from the procedure specified.

Results

 

Sample A will yield the total particulate and water droplet counts. Sample B will yield particulate only. If the results are the same then there is no free water in the sample.

 

If Sample A produces higher counts than sample B then that is a measure of the amount of free water in the sample.