The closed sampler for petrochemical production is mainly used to collect volatile, toxic, harmful, or high-risk medium samples in a closed environment. Through a fully enclosed design, it avoids sample leakage, volatilization, or contact with the outside world, ensuring operational safety, sample integrity, and analytical accuracy
The design of the closed sampler for oil and chemical industry needs to strictly match the industry working conditions, and the core technical features include:
Corrosion resistance: Components in contact with the medium, such as valves, flow tubes, and sampling cups, should be made of corrosion-resistant materials, such as 316L stainless steel (suitable for most oil products), Hastelloy alloy (suitable for strong acid/high sulfur media), and polytetrafluoroethylene (suitable for strong corrosive solvents).
Pressure/temperature resistance: Select the corresponding grade of components based on the process pressure (usually 0.1-40MPa) and temperature (-50 ℃ -400 ℃). For example, high-pressure sampling valves need to meet standards, and high-temperature flow paths need to be insulated or heat traced (to prevent medium solidification, such as paraffin sampling requiring heat tracing to above 50 ℃).
No dead volume design: There are no "dead corners" in the flow path (such as too many right angles or sudden changes in pipe diameter), avoiding cross contamination caused by residual media (such as when switching between sampling different batches of oil, residual media will affect the accuracy of the next sample analysis).
Safety interlock: Some models are equipped with "pressure interlock" (confirming the flow path pressure before sampling to prevent overpressure leakage) and "purge interlock" (automatically purging the flow path with nitrogen after sampling) to reduce the risk of human operation errors.
Ease of operation: adopting a "one click sampling" or "rotary valve" design to simplify the operation steps; Partially equipped with transparent windows, allowing observation of sampling progress and avoiding overfilling.
Precautions for use and maintenance
Pre sampling inspection: Confirm the "material compatibility" between the sampler and the process medium (such as using ordinary stainless steel parts when sampling strong acidic media), valve switch status (to prevent accidental opening and medium spraying), and whether the sealing components (such as O-rings) are intact (to avoid leakage).
Sampling process control:
Liquid sampling: First, exhaust the air or residual medium in the flow path through the "vent valve", and then collect the sample (to ensure sample representativeness);
Gas sampling: The sampling cylinder needs to be evacuated in advance (or replaced with a medium for more than 3 times) to avoid air mixing.
Daily maintenance: Regularly check the sealing of the valve (such as whether there is dripping), whether the flow path is blocked (especially for high viscosity media), and the aging of the seals (it is recommended to replace the O-ring every 6-12 months); Before long-term shutdown, it is necessary to rinse the flow path with a solvent (such as kerosene) to prevent the medium from solidifying and blocking.
Safe operation: Operators need to wear protective equipment (such as oil resistant gloves, goggles, gas masks, for toxic media); Smoking and hot work are prohibited at the sampling site, and fire extinguishers are equipped (for flammable and explosive media).