أجهزة أخذ العينات ذات الحلقة المغلقة

Closed Loop Sampling Systems for Petrochemical Process

Closed loop sampling systems capture representative liquid and gas samples from process streams without releasing vapors to the atmosphere. By returning displaced fluid back to the process line, these systems eliminate operator exposure to hazardous hydrocarbons, reduce fugitive emissions, and ensure sample integrity from the tap point to the laboratory. Wanan Technology manufactures ASME U-stamp and ISO 9001 certified closed loop samplers trusted by Sinopec, ExxonMobil, BASF, and Lukoil for crude oil pipelines, refinery process units, and petrochemical facilities worldwide.

A poorly designed sampling point introduces moisture contamination, phase change, and vapor loss — all of which invalidate custody transfer measurements and quality control results. Wanan closed loop sampling systems are engineered to maintain sample representativeness from the process connection through the sample container, using purging, cooling, and sealed transfer to preserve the integrity of each grab sample.

Key Features of Wanan Sampling Systems

• Zero-emission closed loop design returns purge fluid to the process line, meeting EPA and OSHA vapor-control requirements on crude oil, refined products, and chemical service.
• ASME Section VIII pressure vessel construction with U-stamp certification for sample cylinders operating under pressure from cryogenic to high-temperature service.
• Integrated sampling cooler condenses hot vapors before entering the sample cylinder, preventing flash and ensuring liquid phase integrity in high-temperature streams.
• Self-resetting automatic closure valve seals the sample port immediately after withdrawal, preventing back-flow and reducing contamination risk in multi-product service.
• 316L stainless steel wetted parts standard, with Hastelloy C276, Duplex SS, and PTFE-lined options for corrosive, high-chloride, or H2S service.
• Modular panel configuration mounts on a pipe stand or instrument skid, integrating the sample valve, cooler, pressure regulator, and sample cylinder in a single assembly.

Types of Sampling Systems

Wanan offers a complete range of sampling solutions to match process conditions, regulatory requirements, and operational preferences:

• Closed loop sampler — the industry-standard method for representative liquid sampling on crude oil, gasoline, diesel, and chemical streams. Sample fluid purges through the cylinder, displacing the previous sample back to the pipeline.
• Self-resetting sampler — features an automatic spring-loaded or pneumatic valve that reseals immediately after the sample is withdrawn, ideal for unattended or remote sampling points.
• Sampling cooler (heat exchanger) — cools hot process streams before entering the sample cylinder, maintaining samples in a stable liquid phase for accurate density, viscosity, and composition analysis.
• Sampling fitting and quill — isokinetic sample probes and nozzle fittings that extract a representative cross-sectional sample from the pipe center, critical for multi-phase and high-velocity streams.
• Composite sampler — time- or flow-proportional sampling systems that collect multiple increments over a batch or ship loading, producing a representative composite for custody transfer analysis.

All sampling systems can be paired with ASME certified sample cylinders in various sizes, and with sampling fittings that include needle valves, check valves, and gauge connectors.

المواصفات

التطبيقات

Wanan sampling systems are installed at critical measurement and quality control points across the energy and petrochemical value chain:

• Crude oil pipeline custody transfer metering stations
• Refinery process unit feed and product streams (CDU, VDU, FCC, hydrotreater)
• LNG / LPG loading and receiving terminals
• Petrochemical plant reactor feed, product, and recycle streams
• Tank farm product blending and quality check points
• Offshore platform wellhead and separator sampling

Each project receives an application review covering process fluid composition, temperature, pressure, flow velocity, and regulatory requirements to ensure optimal sampler design and material selection.

الشهادات والمعايير

Wanan sampling systems are designed, manufactured, and tested in accordance with international standards accepted by major operators and inspection authorities:

• القسم الثامن من معايير ASME — pressure vessel design and fabrication for sample cylinders and coolers with U-stamp certification.
• ISO 9001 — quality management system certification covering design, manufacturing, and inspection.
• ASTM D4057 / ISO 3170 — manual sampling of petroleum and petroleum products, ensuring sampler design meets international liquid sampling protocols.
• ATEX / IECEx — explosion-proof classification for pneumatic samplers used in Zone 1 and Zone 2 hazardous areas.
• EAC (CU TR) — Eurasian Conformity for Russia, Kazakhstan, Belarus, and CIS project requirements.

How to Select a Closed Loop Sampling System

1. تحديد شروط العملية. Record fluid type, operating pressure, temperature, flow rate, and any hazardous components (H2S, benzene, LEL vapors).
2. Choose sampler type. Closed loop for standard grab sampling; self-resetting for remote or unmanned locations; composite sampler for custody transfer batches.
3. Select material of construction. Match wetted parts to fluid corrosivity, chloride content, and temperature. SS 316L is standard; Hastelloy or Duplex for aggressive service.
4. Size the cooler. Calculate cooling duty based on inlet temperature and required outlet temperature for liquid-phase sampling.
5. Confirm regulatory compliance. Specify ASME, ATEX, EAC, or other certifications required by the project authority and jurisdiction.

Contact our engineering team with process data sheets for a detailed sampler specification and quotation.

الأسئلة الشائعة

اتصل بشركة «وانان تكنولوجي» for a closed loop sampling system quotation or technical support.