ISO 11171:2020 pdf download Hydraulic fluid power — Calibration of automatic particle counters for liquids
4.2 Clean diluent, consisting of the test liquid used in ISO 16889 and containing:
a) an antistatic additive at such a concentration that resultant conductivity of the clean diluent is (2 500 ± 1 000) pS/m at room temperature; and
b) less than 0,5 % of the number concentration of particles equal to or larger than the smallest particle size of interest expected to be observed in the samples.
4.3 Clean aerosol OT diluent, for use in calibration for particle sizes greater than 30 µm(c) and to determine sensor resolution in Annex D (the clean diluent specified in 4.2 is used for all other operations in this document), which:
a) is prepared from a concentrate made by adding 120 g of aerosol OT to each litre of clean diluent (4.2), which is:
1) heated to approximately 60 °C and stirred until no undissolved aerosol OT is visible to the eye; and
2) diluted with clean diluent (4.2) to a final concentration of 12 g of aerosol OT per litre; and
b) meets the same cleanliness levels as the diluent specified in 4.2. Aerosol OT (dioctyl sulfosuccinate, sodium salt) is a waxy, hygroscopic solid. If it appears damp, or has absorbed water prior to use, dry it first for at least 18 h at approximately 150 °C. NOTE In 4.3 a) 1), it is critical that all of the aerosol OT be dissolved prior to proceeding to 4.3 a) 2). Depending upon the local conditions, complete dissolution can require in excess of 6 hours of heating and stirring as described. WARNING — Follow the precautions for safe handling and usage described in the safety data sheet (available from the supplier of the aerosol OT).
4.4 NIST standard reference material 2806x (SRM 2806x) primary calibration suspension, where x is the letter used by NIST to designate the batch number of the certified primary calibration suspension available from NIST, for use in primary calibrations. SRM 2806b shall not be used for calibrations according to this document.
4.5 NIST reference material 8631x (RM 8631x) dust, where x is the letter used by NIST to designate the batch number of the reference material, available from NIST, prepared by drying the dust for at least 18 h at a temperature between 110 °C and 150 °C, for use if secondary calibration is to be performed (see 6.1).
4.6 ISO medium test dust (MTD) or other test dust conforming to ISO 12103-1, dried for at least 18 h at a temperature between 110 °C and 150 °C before use, for use if secondary calibration is to be performed (see 6.1).
4.7 NIST reference material 8632x (RM 8632x) dust, where x is the letter used by NIST to designate the batch number of the reference material, prepared by drying the dust for at least 18 h at a temperature between 110 °C and 150 °C, before use, required for determination of coincidence error limit and in Annexes A, B, C and E. NOTE The reference materials specified in 4.4, 4.5, 4.6 and 4.7 can change as new batches are produced. Such a change does not affect the particle sizing calibration (Clause 6), but the ability of an APC to meet the counting accuracy requirements of E.9 can be affected if the batch of RM 8632x used to prepare the samples differs from the batch used to create Table A.1.
4.8 Automatic particle counter for liquids, with bottle sampler with at least 8 channels that can be set at various threshold settings.
4.9 Clean sample containers, with closures (appropriate bottle caps, for example), and volumetric glassware of at least class B accuracy as defined in ISO 4787, with cleanliness levels lower than 0,5 % of the number of concentration of particles (larger than the smallest particle size of interest) expected to be observed in the samples, confirmed in accordance with ISO 3722.
4.10 Mechanical shaker, such as a paint or laboratory shaker, suitable for dispersing suspensions.
4.11 Ultrasonic bath, with a power density of 3 000 W/m 2 to 10 000 W/m 2 of bottom area.
4.12 Linear-linear graph paper or computer software, for generating graphics.
4.13 Log-log graph paper or computer software, for generating graphics.
4.14 Analytical or electronic balance, with the following minimum specifications:
a) readability: 0,01 mg;
b) accuracy (agreement with true mass): ±0,05 mg;
c) precision (repeatability): 0,05 mg;
d) front or side doors and a covered top to eliminate the effect of air currents.
4.15 Secondary calibration suspension, prepared according to Annex F for use in secondary calibrations. Secondary calibration samples shall not be used for primary calibrations.ISO 11171:2020 pdf download