What are fluid pipes?
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- May 9,2024

Fluid pipes refer to pipelines used for transporting fluids such as oil, natural gas, and water.
Fluid pipelines are pipeline systems used to transport liquids, gases or gas-liquid mixed media. They are widely used in the fields of petroleum, chemical industry, water conservancy, municipal administration, energy, etc. Their design needs to comprehensively consider fluid characteristics, pressure, temperature, corrosiveness and safety regulations.
1. Core elements of fluid pipelines
Media type: water, oil, natural gas, chemicals, steam, etc., determine material compatibility and anti-corrosion requirements.
Working pressure: high pressure (>10 MPa), medium pressure (1-10 MPa), low pressure (<1 MPa), affecting pipe thickness and connection method.
Temperature range: high temperature (such as steam pipelines require heat-resistant steel), normal temperature or low temperature (antifreeze materials are required).
Flow rate and flow velocity: determine the size of the pipe diameter, and avoid excessive flow rate to cause pressure drop or pipe wear.
Corrosiveness: Acidic/alkaline media require stainless steel, plastic or lined pipes.
2. Classification of fluid pipelines
Water pipes: Drinking water pipes must be non-toxic (such as PE pipes), and industrial water pipes must be rust-proof (galvanized steel). Municipal water supply, cooling water circulation system.
Oil/gas pipes: High-pressure oil and gas transportation requires seamless or thick-walled welded pipes (such as API 5L standard pipeline steel). Oil pipelines, natural gas trunk networks.
Chemical pipelines: Corrosion-resistant materials (such as 316L stainless steel, PTFE lining). Sulfuric acid delivery pipes, reactor connection pipes.
Steam pipelines: High temperature and high pressure resistant (such as ASTM A106 seamless steel pipes), insulation layer is required to reduce heat loss. Power plant steam transportation, industrial heating system.
3. Design standards and specifications
International standards
ASME B31 series: such as B31.1 (power pipeline), B31.3 (process pipeline).
API 5L: Standard for steel pipes for oil and gas transportation.
EN 13480: European industrial metal pipeline standard.
Pressure level
Class 150~2500: American standard pressure level (such as Class 300 corresponds to about 5 MPa).
PN10~PN420: European standard nominal pressure (such as PN16 corresponds to 1.6 MPa).
4. Anti-corrosion and maintenance
Coating protection
Epoxy resin coating: used to prevent soil corrosion of buried pipelines.
Polyurethane foam: insulation and moisture resistance (such as central heating pipelines).
Cathode protection
Sacrificial anode (magnesium/zinc block) or impressed current method, suitable for long-distance buried pipelines.
Regular inspection
Ultrasonic thickness measurement, intelligent pig (PIG) to detect inner wall corrosion or scaling.