JB/T 10560-2017Rolling bearings - Cleanliness of rust preventive oils and cleaning agents and assessment methods (English PDF)

3.1 Terms and definitions

For the purposes of this document, the following terms and definitions apply.

3.1.1 blank experiment

test carried out with a view to inspecting the additional contamination possibly caused by the test conditions (e.g., preparation process of reagents, containers and filter membrane)

3.1.2 solvent

liquid which can mix with liquid sample easily and has physical and chemical properties compatible with the liquid sample

Note: solvent may be used for diluting the liquid sample and may also be used for cleaning and flushing containers and vessels. The chemical properties of solvent cannot solve the filter membrane and the particles on filter membrane.

3.1.3 effective filtration area (EFA)

area of the circle formed on the filter membrane when the liquid flows through filter membrane during filtration

3.1.4 fibre

particle with length larger than 100µm and length-to-width ratio larger than or equal to 10:1

3.1.5 image analyser

instrument capable of automatically analysing the particle size and calculating the number of particles on filter membrane

Note: according to the color difference between particles and background, the image analyser converts the distribution image of particles on microscope into screen image via camera and also automatically calculates the size and number of particles and shows them on the view screen.

3.1.6 particle size

the maximum size X of contaminant particles (see Figure 1)

Figure 1 Examples for Maximum Size of Particles

3.1.7 unit area

certain area specified on the filter membrane in order to carry out statistical counting (see Figure 2)

Figure 2 Example for Unit Area

3.1.8 grid square

grid square (nominal size: 3.1mm) printed on filter membrane for the purpose of statistical counting of particles (see Figure 3)

Note: the grid-square filter membrane is not applicable to automatic image analysis.

Keys:

1 - - 10 grid squares; 2 - - 20 grid squares; 3 - - 50 grid square; 4 - - effective filtration diameter (EFD) of filter membrane.

Figure 3 Examples for Grid-square Filter Membrane and

Selection of Its 10, 20 and 50 Counting Grid Squares

3.2 Symbols

For the purposes of this document, the following symbols apply.

A: the effective filtration area (EFA) of filter membrane, mm2 f: the number of counting units

L: the length of unit (or grid square) in effective filtration area, mm

M: the mass of contaminants in liquid sample, mg n: the number of particles no less than the selected size in one unit (or grid square)

V: the volume of liquid sample after filtration, mL

W: the width of unit (or grid square) in effective filtration area, µm

4.1 Measurement principle with weighing method

Carry out vacuum filtration to the liquid sample of known volume, collect the contaminant particles onto two overlapped filter membranes, and the difference between mass increments of two filter membranes after filtration is equivalent to the content of contaminants in liquid sample.

4.2 Measurement principle with particle counting method by microscope

Carry out vacuum filtration to the liquid sample of known volume, collect the contaminant particles onto filter membrane, and carry out particle counting with microscope, and it is also possible to count the number of particles within different size ranges as needed.

It is possible to automatically analyse the particle size and calculate number of particles on filter membrane by means of image analyser (digital microscope) together with automatic cleanliness analysis system.

5.1

The measuring environment should reach the Grade 5 air cleanliness listed in Table 1 of GB/T 25915.1-2010, or a better grade.

5.2

As some solvents used in the fabrication process of test pieces are volatile liquid, favorable indoor ventilation shall be maintained in order to avoid human body inhaling the harmful solvent gas.