JPS5937444A - Method for measuring minute particle in hydraulic fluid - Google Patents

Abstract

PURPOSE:To measure exactly the size and the number of minute particles in a hydraulic fluid, by collecting particles with a patternless thin membrane filter, and placing on the filter a glass plate having scribed lattice patterns. CONSTITUTION:A patternless thin membrane filter 1 which has 47mm. diameter, and <=0.8mum pores as specified in the Japanese Industrial Standard, is placed on a supporting table. An upper funnel is attached to the filter 1, while preventing said funnel from slipping and covered. A sample is shaken so that included minute particles may be uniformly dispersed, placed in a messcylinder by 100ml, transferred to the upper funnel, and covered. After the particles are collected on the filter 1 by operating a suction pump, the filter 1 is removed from the supporting table, placed on a slide glass 2, and covered with a glass plate 3. The under-surface of the slide glass 3 is patterned with scribed lattices 3a at intervals of 3.1mm.. Thus, the number and the size of the particles can be measured by means of a microscope.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for measuring particulates contained in hydraulic oil.

In the conventional measurement method of this type, JIS B 993
It was measured using a measurement thin film filter used in microscopy method specified as 0. This thin film filter for measurement has a diameter of 47 mm, a pore size of 0.8 μm or less, and a grid with a side of 3.1 mm is printed on it.

However, when such a filter is used to collect particulates in hydraulic fluid, there is a possibility that the particulates may land on the grid lines, making it difficult to determine the filter's lattice frame (and thus the size and number of particulates). There was a difficulty in measuring accurately.

Furthermore, when it is desired to observe the entire particulate matter collected on the filter, the grid lines become an obstacle, making observation difficult.

The present invention has been made to effectively eliminate such inconveniences, and its purpose is to collect fine particles in hydraulic oil with a patternless filter, and place the filter on the stage of a microscope. In addition to allowing for overall observation, when measuring the size and number of fine particles, place a glass plate with grid-like marking lines on the top of the filter to accurately measure the size and number of fine particles. An object of the present invention is to provide a method for measuring particulates in hydraulic fluid.

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a perspective view of the filter and the glass plate, FIG. 2 is a side view showing the state of the filter and glass plate during measurement, and FIG. 3 is a plan view thereof.

Regarding measurement methods, JIS B9930 stipulates the microscopy method and automatic particle counter method, but the following method uses the microscopy method, that is, sucks up hydraulic oil using a suction pump and places it on the surface of a thin film filter for measurement. A method for measuring the size and counting the collected particles with a diameter of 5 μm or more using a microscope will be described.

In the method of the present invention, a patternless filter 1 is used as the thin film filter for measurement, and the large diameter etc. of this filter 1 are the same as those specified in JIS. That is, the diameter is 47y++m and it is 0.8
It shall have a pore diameter of μm or less.

The collection of fine particles is carried out in accordance with the methods and procedures specified in JIS as follows.

That is, take out one of the filters 1 from the container using tweezers, rinse both sides of it with filtered petroleum ether, place it on a filter support, and attach the upper funnel onto the filter 1 without slipping. , Secure this securely with the clamp and cover the funnel. Shake the material in the sample bottle thoroughly to suspend it so that the particles are as uniform as possible. After discarding a few ml of the sample in advance, pour 100 ml into the measuring cylinder, transfer it to the upper funnel, and close the lid. .

Next, activate the suction pump and pump the sample in the upper funnel to a depth of 50 m.
, the suction is stopped leaving about 1 liter remaining, and the particulates are collected on the filter 1. Then, the filter 1 is removed from the filter support base, placed on a clean slide glass 2 as shown in FIGS. 1 and 2, and covered with another glass plate 3. As shown in FIG. 3, the lower surface of the glass plate 3 is provided with marking lines 3a in the form of a grid of 3.1 mm on each side.

The measurement of fine particles is carried out as follows.

As shown in FIG. The marking lines 3a... are made to coincide with the coordinate axes of the movable stage.

After confirming at low magnification that the collected particles are uniformly dispersed, the passing particles are measured on the scale of an eyepiece micrometer while moving the stage of the microscope.

The number of particles in the target particle size category is 1 within the effective filtration area.
If it is estimated that there are ~50 grids, measure the entire effective filtration area; if it is estimated that there are 50 to 1000 grids, measure 20 randomly selected grids and add 5 to this. Multiply to obtain the number concentration of particles, 1001 to 50
If it is estimated that there are 00 particles, measure the particles on 10 arbitrarily selected grids and multiply this by 10 to obtain the number concentration of particles, and if it is estimated that there are more than 5,000 particles, calculate the number concentration of particles arbitrarily. The number of particles is measured for each particle in a certain area within the selected 10 grids.

In the above, a patternless filter 1 is used, and a lattice-like marking A3a is applied to the glass plate 3 covering the top surface of the filter to indicate the size and number of the collected particles.
・This marking line 3
a... Even if there are fine particles on the surface, they can be accurately measured, and therefore the measurement accuracy is significantly improved.

In addition, when observing the entire particulate matter collected on the filter 1, if the glass plate 3 is removed, the grid lines will not be an obstacle as in the past, and the entire observation will be easy. Can be done accurately.

According to the present invention, the above effects can be obtained.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a perspective view of a filter and a glass plate, FIG. 2 is a side view showing the state of the filter and glass plate during measurement, and FIG. 3 is the same. FIG. In the drawings, 1 is a filter, 2 is a slide glass, 3 is a glass plate, and 3a is a marking line. Patent applicant Showa Seisakusho Co., Ltd.

Claims (1)

[Claims] In a method in which fine particles contained in hydraulic oil are collected with a thin film filter and the filter is placed on a stage of a microscope to measure the size and number of the fine particles, the thin film filter is made without a pattern and the filter is A method for measuring particulates in hydraulic oil, characterized in that a glass plate with marking lines in a grid pattern is placed on the top surface, and particulates on a filter are measured by using the glass plate as a valve.