High-pressure carbon steel for gas conduits includes control valves, filters, pressure relief devices, pressure gauges, flowmeters, on-line analyzers, etc., and should be concentrated in the intake chamber. After pressurizing the gas through blowers, compressors, pumps and boilers, it flows from high pressure to low pressure in the pipeline and can also be transported through the pressure or gravity of the gas itself. When the velocity of the gas is known, the diameter of the pipe depends on the allowable velocity or the allowable frictional resistance (pressure drop). When the flow rate is high, the diameter of the pipeline is small, but the pressure drop increases. However, the operating energy cost of power equipment such as pumps and compressors increases. In addition, if the flow rate is too high, there may be other disadvantages. Therefore, the diameter of pipeline should be determined according to construction investment, operation cost and other technical factors.


High-pressure carbon steel used in gas conduits may be subjected to various external forces, including their own weight, thrust at the end of the pipe, wind and snow loads, earth pressure, thermal stress caused by thermal expansion and contraction, vibration loads, and earthquake disasters. In order to ensure the strength and stiffness of the pipeline, it is necessary to provide a variety of support (suspension) brackets, such as movable bracket, fixed bracket, guide bracket and spring bracket. The bracket setting depends on the diameter, material, wall thickness and load of the pipeline. Fixed bracket is used to control the thermal elongation of pipeline in stages to make the expansion joint work uniformly; guide bracket allows the pipeline to move only axially. In order to remove condensate water, steam and other water-bearing gas pipelines should have a certain gradient, generally not less than two thousandths. For underground drainage pipelines using gravity flow, the slope is not less than five thousandths. Steam or other water-bearing gas pipes are provided with drainage pipes or traps at the lowest point.  Some high-pressure carbon steel used in gas pipelines are also equipped with gas-water separators to remove water from water in time to prevent water hammer and obstruct air flow. The water supply or other liquid pipes are equipped with ventilation devices at the highest point to remove accumulated air or other gases in the pipes so as to prevent the gas barrier from causing failure. If the pipeline cannot be stretched flexibly, it will generate enormous additional pressure.  Therefore, expansion joints are needed to compensate for expansion and contraction of pipes and eliminate the effect of additional stress on pipes with large temperature variation and normal temperature pipes with free displacement. For steam pipes, high temperature pipes, cryogenic pipes and pipes with anti-scalding and anti-freezing requirements, insulating materials must be used to cover the outside of pipes to prevent loss of heat (cold) or freezing. The Conduit. The commonly used insulation materials are cement perlite, glass wool, rock wool and asbestos diatomite.


Connection method
The connection method between the inlet and outlet pipes on pipes, pipe joints, valves and equipment depends on the nature of the gas, pressure and temperature, as well as the material, size and installation position of the pipes, mainly including threaded joints, flange connections and sockets. Four kinds of connection and welding methods.