Gas pressure regulators are essential components in city gas distribution systems, ensuring safe and efficient delivery of gas to end users. These devices typically consist of multiple functional modules, including the pressure regulator itself, a filter for cleaning the gas, a heat exchanger to prevent ice blockage caused by rapid gas expansion, and a flow meter for accurate measurement. These parts are assembled using welding and flange connections to create a fully functional pressure regulating system.
When designing such devices, it is crucial to understand their classification under current industry standards. Unlike pressure vessels or pipelines, gas pressure regulators fall into a unique category. Some manufacturers mistakenly classify them as non-standard equipment, leading to improper compliance with safety regulations. According to the Special Equipment Safety Supervision Regulations (issued by the State Council in 2003), these devices should be considered "component combination devices" and must adhere to specific manufacturing and inspection requirements. The manufacturer must apply for a special equipment production license from AQSIQ before starting any work, and related components like heat exchangers and filters must be produced by licensed pressure vessel manufacturers.
The design and manufacturing process should also account for different pressure levels. Depending on the inlet and outlet pressures, various materials and testing methods may be used to optimize performance while reducing costs. For example, flanges, valves, and pipes can be selected based on their pressure rating, and non-destructive testing of welds should be conducted accordingly. Each section should undergo individual strength tests, and an airtightness test should be performed after assembly.
Safety is a top priority when designing gas pressure regulators. Key measures include installing emergency shut-off valves and safety relief valves. The emergency shut-off valve is placed upstream and automatically closes if the pressure exceeds its set point, protecting downstream equipment. It also triggers a shutdown if there’s a leak, preventing further damage. The safety relief valve, located downstream, releases excess gas to prevent overpressure and potential explosions.
Static electricity buildup is another concern, especially at flange and threaded connections. To mitigate this, copper wires or plates should be installed across joints where resistance exceeds 0.03 ohms. These should be rust-proof and not painted to ensure conductivity. Proper grounding is also necessary, with two grounding leads required if the system’s resistance exceeds 100 ohms.
Odorization is essential for gases like natural gas, which are odorless. According to GB 50028–2006, non-toxic gas should be detectable at 20% of its lower explosive limit. Odorants like tetrahydrothiophene (THT) or ethanethiol are commonly added to make leaks more noticeable, and an odorizing port is usually installed at the outlet of the regulator.
Pressure and temperature measuring instruments should be placed after each stage of regulation to monitor system performance. Remote monitoring capabilities can enhance operational efficiency and safety.
In conclusion, as the use of clean energy like natural gas increases, so does the need for reliable and safe pressure regulators. Without clear standards, design flaws can lead to serious safety risks. Authorities must strengthen oversight of design, manufacturing, and installation to ensure quality and reliability. (Source: Hebei Zhenxing Gas Pressure Regulator Co., Ltd.)
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