Photo

 mpc mpc-2

Test equipment

Fluitec iLab Color meter

Millipore patch maker, with vacuum filtering flask

Oven (to pre-treat oil samples)

Mettler Toledo Analytical balance (to measure weight of patch)

Lightbox and camera (to photograph patch)

Sample size

100ml (recommended), 50ml (minimum)

Standard

ASTM D7843

Unit

ΔE value in the CIE LAB scale

Test methodology

First, the sample is homogenized, heated to dissolve oxidation precursors and then allowed to stand for the soft contaminants to be insoluble.

The standard recommended astm method is as follows:

The sample shall be heated to 60–65°C for 23–25 h then stored between 15–25°C, away from UV light for an incubation period of 68–76 hours.

Now 50 ml of the sample and 50 ml of filtered heptane is stirred and filtered through a membrane with a pore size of 0,45 µ, then the membrane is dried and weighed.

The color of the residues on the patch is analyzed with a spectral sensor, and reported as ΔE value. After that, the membrane patch is placed inside a photolightbox, and a photo is taken.

Notes (application)

The increase of the MPC-factor correlates to the potential of the oil to form residues or varnish. A high MPC-index indicated high amounts of colored bodies concentrated on the patch/membrane.

Varnish on journal bearings reduces the tolerance gap between the surfaces of the bearing and shaft, increase operating temperature and influence the load carrying capability of the bearing.

Typical indicators for varnish are reduced service life of filters, or residues at the tank walls.

Suitable for systems

Gas and steam turbines; circulating systems, hydraulic systems, compressors and bearing lube systems.