1 Scope
This document specifies a method for the calibration and validation of on-line liquid automatic particle counting systems.
This document applies to the following applications:
-- for the calibration of liquid automatic particle counters for the validation of suspension preparation equipment;
-- To carry out on-line calibration of automatic particle counters for liquids;
-- Matching of two and more on-line liquid automatic particle counters, e.g. for counting particles at a given size from two associated on-line liquid automatic particle counters;
--Validation of online particle counting systems with or without dilution, e.g. determination of the filtration efficiency of hydraulic filters in the multiple pass test of filters according to GB/T 18853.
2 Normative references
The content of the following documents is referenced by normative references in the text and hatching the essential provisions of the cost document. Among them, note the date of the reference document, only the date of the corresponding version applies to this document; not note has been the date of the reference document, its latest version (including all the revision of the list) applies to this document.
GB/T 17446 Glossary of fluid power transmission systems and components (GB/T 17446-2012, ISO 5598.2008, IDT)
3 Terms and definitions
The terms and definitions defined in GB/T 17446 and GB/T 18854 are applicable to this document.
4 Units of measurement
The international system of units according to ISO 80000-1 is used in this document.
This document uses um or pm(c) as the unit of particle size, indicating that particle size measurements are made using a liquid automatic particle counter calibrated to GB/T18854.
5 Materials and equipment
5.1 The calibrated liquid automatic particle counter, or liquid automatic particle counting system with two independent sensors, should be calibrated or validated.
5.2 A standard liquid automatic particle counter, which has been calibrated to GB/T18854 using a standard substance.
5.3 ISO intermediate test dust (ISO MTD), conforming to specification A3 of GB/T 28957.1, dried at 110 °C to 150 °C for at least 1 h and then used in the test system, first mixed with the test liquid and stirred thoroughly, and then ultrasonically dispersed with a power density of 3 000 W/m3 to 10 00o w/m'. Ultrasonic dispersion.
5.4 Calibration fluid, should be consistent with the provisions of GB/T18853.
5.5 Hydraulic equipment, should include;
a) tanks, pumps, fluid temperature control systems and instrumentation that meet the verification requirements of Chapter 8.
b) purification filters, which shall ensure that the initial particle concentration of the fluid is such that the number of particles of the smallest size calibrated per ml of fluid is less than 50 or less than 2% of the desired value
c) Equipment constructed in such a way that the particle size distribution does not change within the expected calibration time (see GB/T 18853); d) Liquid sampling devices, in accordance with GB/T 17489; and
e) A system configuration for automatic particle counters for liquids with constant flow and constant temperature of contaminated liquids, with an accuracy of flow and temperature within the limits of Table 1.
Note 1: Multiple pass test benches (see GB/T 18853) may be used provided that they have been uniquely certified in accordance with Chapter 8 of this document.
Note 2: A selection of more satisfactory typical configurations is given in Appendix VIII.
5.6 Hydraulic circuit for the connection of an in-line liquid automatic particle counter to a multiple splash-through test bench. If required, a dilution system should be included.
6 Accuracy of the measuring equipment and test conditions
The accuracy of the measuring equipment used should be within the limits specified in Table 1.
Warning: Ensuring that the test conditions are within the limits of Table 1 does not mean that the validation requirements will be met. It has been demonstrated that the most effective way of meeting the validation requirements is to ensure that the test conditions given in Table 1 are met, while using a suitable particle counting procedure and correctly designed hydraulic equipment.
7 Liquid automatic particle counter off-line calibration procedure
7.1 The liquid automatic particle counter is dimensionally calibrated in accordance with the recommendations of the liquid automatic particle counter manufacturer and in accordance with GB/T 18854 for new or overhauled liquid automatic particle counters.
7.2 Determine the coincidence error limits of the liquid automatic particle counter and sensor in accordance with the procedure specified in GB/T 18854 or use the specified values obtained by the manufacturer using the same method.
8 Online verification of hydraulic equipment
8.1 This procedure is used to verify that the following conditions are met
a) whether the particle size distribution of the circulating suspension in the equipment remains stable for a specified period of time
b) whether representative samples are available at the sampling point or bottle sampling point, see Figure 1 for the complete procedure.
8.2 Use an automatic particle counter for liquids calibrated according to Chapter 8, set to the cumulative counting mode and set at least 6 different thresholds in the relevant particle size range. Thresholds outside the relevant particle size range in this document cannot be set.
Note: As this procedure is only intended to verify the stability of the particle count values over a certain period of time, a standard liquid automatic particle counter may not be used.
8.3 The total volume of liquid in the suspension preparation equipment is adjusted to the design maximum and measured with an error of ±1%, maintaining a liquid viscosity of (15±1.0)mm*/s.
8.4 Circulate the liquid through the purification filter at a given flow rate until the number of particles larger than 5 um per ml of liquid is less than 5. 8.5 Determine the mass of ISO MTD test dust to be added to the system to a concentration of (3±0.3) mg/L. Record the batch number of the ISO MTD test dust.
8.6 Prepare the test dust in accordance with 5.3. Close the purification filter and add the ISO MTD test dust to the tank in the required quantity and circulate for approx. 15 min,
9 Online calibration of the automatic particle counter for liquids
9.1 The liquid automatic particle counter is calibrated online without dilution. Connect the reference liquid automatic particle counter to the hydraulic equipment verified in chapter 8 and prepare the test dust according to 8.3 to 8.6. Measure at least three consecutive online counts at a minimum of 25 mL for a number of particle sizes (after the counts have stabilised), which correspond to particle sizes covering the size range of the liquid automatic particle counter used, and enter the data in Table 3, column?
10 Matching of two and more automatic liquid particle counters
10.1 This chapter applies to the consistent matching of two or more automatic liquid particle counters used upstream and downstream of the filter to measure the filtration efficiency of their different particle sizes.
10.2 This chapter does not apply to the calibration of one or two liquid automatic particle counters (sensors), which should be calibrated offline in accordance with chapter and online in accordance with chapter 9.
10.3 Connect the liquid automatic particle counter calibrated according to chapter 9 (online calibration) and the other liquid automatic particle counter (sensor) to be matched to the sampling point of the hydraulic equipment verified in chapter 8. A dilution system should not be used when the two automatic liquid particle counters (sensors) are matched together.
10.4. Set the automatic liquid particle counter to the cumulative counting mode and set at least six different threshold values in the relevant particle size range. 10.5. Adjust the total volume of liquid in the hydraulic equipment to a predetermined value within ±1%. The fluid viscosity should be maintained at (15'/1.0) mm'/s. The number of particles of each size should be greater than 10 particles/mL.
10.6 Circulate the liquid through the purification filter until less than 5 particles larger than 5.m per mL of liquid are achieved.
10.7 Determine the concentration value to be used for matching the ISO MTD suspension so that the maximum value of particle count at the smallest particle size is close to 75% of the concentration limit of the automatic particle counter for liquids as determined in 7.2. Prepare according to 5.3 and record the batch number of the ISO MTD.
10.8 Turn off the purification filter and add the prepared suspension to the tank and circulate for approximately 15 min or until the count values stabilise for all size ranges. 10.9 Perform an on-line automatic count at 1 min intervals for at least 30 min.
10.10 Calculate the permissible deviation of the automatic particle counter (sensor) for liquids at each particle size according to equation (4) and record it in Table 4.
Allowable deviation between particle counters (sensors) = 4.925 6 + 0.013 2 x (average count value of sensor No. 1) ......( 4 ) Note: The deviation between particle counters (sensors) has been verified in the international joint validation.
10.11 Adjust the threshold of the peal liquid automatic particle counter (sensor No. 2) so that the average count value per ml matches the average count value of liquid automatic particle counter No. 1 (sensor No. 1) with the permissible deviation satisfying the requirements of equation (4), and repeat for the other liquid automatic particle counters (sensors) as per this chapter article.
11 Validation of online dilution and particle counting systems
11.1 Validation of the online dilution system is carried out with the same frequency as the online calibration. The calibration process is shown in Figure 2.
11.2 The diluent used should be filtered and contaminated to a level of less than 5 particles per ml greater than 5 pm, unless it can be determined that a higher contamination level of the diluent will not affect the particle counting results by more than 1%.
11.3 Validation is first carried out at the minimum dilution ratio, then at the intermediate dilution ratio and then at the maximum dilution ratio. 11.4 The sample is circulated through a purification filter until the contamination level of the liquid reaches a level of less than 5 particles per ml greater than 5 um. 11.5 The ISO MTD calibration suspension is prepared according to the test procedure in 8.3 to 8.6, but at a concentration of (75) % of the concentration limit shown in 7.2. (75 earth 10)% of the concentration limit shown in 7.2 multiplied by the chosen dilution ratio. Record the ISO MTD batch number used.
12 Notes
13 Notes on labelling
Appendix A (informative) Design guide for a typical on-line calibration and validation system
1 Scope
2 Normative references
3 Terms and definitions
4 Units of measurement
5 Materials and equipment
6 Accuracy of the measuring equipment and test conditions
7 Liquid automatic particle counter off-line calibration procedure
8 Online verification of hydraulic equipment
9 Online calibration of the automatic particle counter for liquids
10 Matching of two and more automatic liquid particle counters
11 Validation of online dilution and particle counting systems
12 Notes
13 Notes on labelling
Appendix A (informative) Design guide for a typical on-line calibration and validation system
