颗粒计数器取样容器怎么选

When conducting particle contamination testing, whether collecting sample liquid in the liquid tank or in the system pipeline for testing and analysis, the first thing to come into contact with is the sample container. The material, shape, cleaning, and cleaning method of the sampling container are the key to whether all subsequent work is meaningful.

Requirements for selecting sampling containers

Shape: The sampling container should be a cylindrical shape that is convenient to carry, with smooth inner and outer surfaces of the bottle body, rounded corners at the bottom, and a smooth bottle mouth to prevent solid particles from accumulating in these areas; The volume is generally not less than 150ml;
Material: Colorless and transparent, materials that are prone to aggregation or particle formation in the liquid sample are not allowed;
Compatibility: The sampling container must be compatible with the collected liquid sample;
High and low temperature resistance: The range of high and low temperature resistance of the sampling container should meet the temperature requirements of the collected liquid sample, transportation, and storage. It is not allowed to change the shape and material of the sampling container due to extreme high and low temperatures during the collection, transportation, and storage of the liquid sample, which may affect the authenticity of the liquid sample;
Sealing: The sampling container must have sealing performance. If the sealing of the container is poor, it is easy to cause leakage during the transportation or processing of liquid samples (before conducting solid particle contamination testing on the liquid sample, manual or mechanical shaking is required to evenly suspend and disperse the solid particles in the liquid sample), which is not convenient to carry and can easily cause secondary pollution;
Cleanliness level: Cleanliness level is a key parameter of the sampling container that can be determined based on the degree of contamination of the liquid sample. For heavily contaminated liquid samples, a specially cleaned sampling container is not necessary. When analyzing liquid samples with particularly high cleanliness requirements, the container must be very clean;
Identification: The sampling container should have corresponding labels for filling in relevant sampling information. The labels generally contain information such as the cleanliness level of the sampling container, sampling unit, sampling location, liquid sample name and model, liquid sample number, sampling date, sampling personnel, etc. Special attention should be paid to the label. The interface marking line that should be reached when taking liquid samples should be aligned with about 75% of the total volume of the sampling container when sticking, leaving sufficient shaking space for liquid sample processing.

Requirements for cleanliness level of sampling containers

The selection of sampling containers should be closely related to the target cleanliness level. In the technical standard GJB380.1A-2015 "Aviation Working Fluid Pollution Testing Part 1: General Requirements and Cleaning Method Identification for Sampling Containers", the target cleanliness level of sampling containers is specified as follows:

The sampling container used for taking liquid samples with solid particle pollution levels higher than GJB 420A-3 should have a target cleanliness level at least 4 levels higher than the collected liquid sample;
The sampling container used for taking liquid samples with a solid particle pollution level of GJB 420A-3 should have a target cleanliness level of at least GJB 420A-0;
The sampling container used for taking liquid samples with solid particle pollution levels lower than GJB 420A-3 should have a target cleanliness level at least 2 levels better than the collected liquid sample, or its solid particle count should not exceed 25% of the collected liquid sample.

Cleaning methods for sampling containers

Use solvents such as detergent or petroleum ether to scrub the interior of the sampling container to remove oil stains and dirt;
Place the sampling container in the ultrasonic cleaning tank, inject clean hot water and an appropriate amount of cleaning solution, soak the container in water for ultrasonic cleaning;
Drain the sewage from the cleaning tank, replace it with new water, and perform ultrasonic cleaning again;
Take out the sampling container, rinse it repeatedly with clean water 2-3 times, then invert the container and empty the remaining water;
Dry in a drying oven or rinse with high-precision filtered isopropanol/industrial alcohol to evaporate residual water as soon as possible;
Using high-precision filtered petroleum ether for flushing, the cleanliness level of the sampling containers is tested one by one using a liquid particle counter;
Pour out the petroleum ether from the sampling bottle that meets the cleanliness requirements, control the drying process, and tighten the cap with the same clean bottle cap.

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Selection requirements and cleaning methods for sampling containers