Fluitec MPC

Will your oil produce varnish ?

The Membrane Patch Colorimetry (MPC) test is a quick, cost-effective way of assessing your oil's varnish potential. Varnish formation & Lubricant oxidation results from the thermal stressing of lubricating oil, and the by-products of oxidation can lead to the formation of varnish in hydraulic control and lubricating oil systems.
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MPC is the only ASTM method for determining Varnish Potential

ASTM D7843 : Standard Test Method for Measurement of Lubricant Generated Insoluble Color Bodies in In-Service Turbine Oils using Membrane Patch Colorimetry.
Lubricating oils used in applications such as compressors, turbines and hydraulic systems are prone to reliability and performance problems due to oil deposits like sludge and varnish. MPC test is designed to separate oil degradation products and measure their color. This indicates the likeliness of deposits causing performance problems in your system.

The MPC Color instrument allows real time on-site determination of the condition of your lubricant. Data results are captured and stored in text and audio captions for quick analysis. The MPC Color packs tremendous science into a convenient and extremely accurate package.
 
Varnish on Shaft Varnished Pencil Filter Spark Discharge within Oil Reservoir








 
Test result MPC-Index; Luminanz L, red value a, yellow value b, solid contaminations (weight in %)
Result range none (Index)
Analysis of Gas and steam turbines; Circulation systems; Hydraulic systems
Brief description After arriving in the lab the sample is stored for minimum 5 hours to be sure that the auto degradation process is finished and all soft contaminants have been become insoluble. Before measurement the sample has to be homogenized e.g. through shaking. Now 50 ml of the sample and 50 ml of filtered heptane is slowly steered together. A membrane with a pore size of 0,45 µ is dried and weighted. The oil and heptane mixture is filtered under a vacuum of 710 mbar. After drying the membrane for 3 hours at 80°C it can be weighted again to calculate the increase of weight in percent.
The color of the residues on the patch is analyzed with a spectral sensor. A LED light source consisting out of three LED’s emits light within the visible spectrum. A typical human eye will respond to wavelengths from about 380nm to 750nm. The residue on the membrane reflects or absorbs the light at specific wavelengths. A sensor detects the reflected light over the whole visible light spectra. The software of the device gives the raw data of the spectrum as output and calculates the CIELAB coordinates according ASTM E308.
Statement The increase of the MPC-factor correlates to the potential of the oil to form residues or varnish. A high MPC-Index means that a high amount of coloured bodies is concentrated on the filter material. These soft particles are very polar and have a high molecular weight. They become oil insoluble by conglomerating together and form a hard and sticky deposit on oil wetted surfaces. The deposit is called varnish and can be the reason for malfunctions of valves and handicap the oil based control of the turbine.Varnish on bearing-seats of friction-type bearings change the geometry of the bearing and influence the load carrying capacity of the bearing.
Typical Indications for varnish are e.g. decreasing service life of filters, or residues at the tank wall.
  • A surface preview capability with built-in calibration tile
  • Produces results in 1.8 seconds
  • Enough memory to store data for up to 350 samples and 20 standards
  • Connects to your PC via USB connection for ease of data transfer and charging
  • Reports color values in CIE, the same scale used in ASTM D7843
  • Includes trend results software called CapSure©
  • It provides repeatable and stable measurements that are not affected by surface irregularities
  • A light weight hand held device making the MPC Color as comfortable in the laboratory or in the plant
  • Employs independent tri-directional 25 LED light source with 8 different visible illuminations

This product is compliant with the following test methods:

  • ASTM D7843