Process Engineering Division – Instrumentation and Automation Section – Daily Question – Question dated 2020-08-21

1) The connections between branch pipes and main pipes, as well as between branch pipes themselves, should be made using threaded connections; welding is not allowed. 2) After threading, remove any burrs or debris from inside the pipes, clean them thoroughly, and then cover both ends to prevent dirt from getting in. 3) The pipes should be installed horizontally and vertically, in an orderly and aesthetically pleasing manner, without any intersections. They must be firmly fixed to the supports using pipe clamps; they cannot be buried underground but should be installed overhead. The gas supply shut-off valve is generally installed at a distance of 1–1.5 meters from the instrument’s gas supply port. 4) After installation, perform a purge test with air.

1) The connections between branch pipes and main pipes, as well as between branch pipes themselves, should be made using threaded connections; welding is not allowed. 2) After threading, remove any burrs or debris from inside the pipes, clean them thoroughly, and then cover both ends to prevent dirt from getting in. 3) The pipes should be installed horizontally and vertically, in an orderly and aesthetically pleasing manner, without any intersections. They must be firmly fixed to the supports using pipe clamps; they cannot be buried underground but should be installed overhead. The gas supply shut-off valve is generally installed at a distance of 1–1.5 meters from the instrument’s gas supply port. 4) After installation, perform a purge test with air.

Set the drain point at least 50 cm away from the process pipelines to minimize vibration; install isolation valves in separate sections

The internal parts of the instrument air supply pipes must be cleaned thoroughly before installation. The installation of gas supply pipelines should avoid areas that may hinder maintenance, or are susceptible to mechanical damage, vibration, and corrosion. The gas supply pipeline should be cut using mechanical methods, and the cut surface should be smooth, free of cracks, scale, burrs, irregularities, or shrinkage. The gas supply pipes should be neat and tidy, with the outlet points of the branch pipes on the horizontal main pipes located above those main pipes. The instrument air supply branch pipes are made of galvanized steel pipes, connected using threads; elbows should be used at turns, and the connections must be sealed. When winding sealing tape or applying sealant, it should not enter the tube. The threading of the gas supply pipes should be carried out using oil-free threading equipment; that is, the oil supply switch on the electric threading machine should be turned off during threading, or manual threading can be used instead. After threading, any dirt present on the threads should be removed promptly. The air supply pipeline should be installed overhead, rather than on the ground or underground. U-shaped piping should be avoided, and a drain valve should be installed at the lowest point in a given area; ball valves or globe valves are suitable for use as such drain valves. When the straight-line distance of the gas supply pipeline is long or there are many branches and elbows, flexible joints should be installed appropriately to facilitate pipeline disassembly. The piping of the gas supply lines should be horizontal, vertical, neat, and aesthetically pleasing. The distance between the outer surfaces of adjacent pipes should not be less than the outer diameter of the larger pipe among them. Drain valves should be installed at the ends and at the liquid collection points, and the drain outlets should be placed away from instruments, electrical equipment, and wiring terminals. There should be enough operating space between the drain valve and the ground. The galvanized gas supply pipes should be fixed to the supports using pipe clamps, with a secure fixation. The spacing between the supports should be 1.5–2 meters, and this spacing must be uniform. When bending metal pneumatic signal pipes, use a pipe bender for cold bending, and the bending radius must be at least 3 times the outer diameter of the pipe; after bending, there should be no cracks, dents, wrinkles, or elliptical shapes. When fixing stainless steel pipes, they should not come into direct contact with carbon steel materials. Before the instrument air is introduced to each supply point, a gas source ball valve should be installed. The gas source enters the valve after being purified by an air filter and pressure regulator, and the filter and pressure regulator should be installed vertically.

1) The connections between branch pipes and main pipes, as well as between branch pipes themselves, shall be made using threaded connections; welding is not permitted

1) The connections between branch pipes and main pipes, as well as between branch pipes themselves, should be made using threaded connections; welding is not allowed. 2) After threading, remove any burrs or debris from inside the pipes, clean them thoroughly, and then cover both ends to prevent dirt from getting in. 3) The pipes should be installed horizontally and vertically, in an orderly and aesthetically pleasing manner, without any intersections. They must be firmly fixed to the supports using pipe clamps; they cannot be buried underground but should be installed overhead. The gas supply shut-off valve is generally installed at a distance of 1–1.5 meters from the instrument’s gas supply port. 4) After installation, perform a pressure test and purging with air

1) The connections between branch pipes and main pipes, as well as between branch pipes themselves, should be made using threaded connections; welding is not allowed. 2) After threading, remove any burrs or debris from inside the pipes, clean them thoroughly, and then cover both ends to prevent dirt from getting in. 3) The pipes should be installed horizontally and vertically, in an orderly and aesthetically pleasing manner, without any intersections. They must be firmly fixed to the supports using pipe clamps; they cannot be buried underground but should be installed overhead. The gas supply shut-off valve is generally installed at a distance of 1–1.5 meters from the instrument’s gas supply port. 4) After installation, perform a purge test with air.

1) The connections between branch pipes and main pipes, as well as between branch pipes themselves, should be made using threaded connections; welding is not allowed. 2) After threading, remove any burrs or debris from inside the pipes, clean them thoroughly, and then cover both ends to prevent dirt from getting in. 3) The pipes should be installed horizontally and vertically, in an orderly and aesthetically pleasing manner, without any intersections. They must be firmly fixed to the supports using pipe clamps; they cannot be buried underground but should be installed overhead. The gas supply shut-off valve is generally installed at a distance of 1–1.5 meters from the instrument’s gas supply port. 4) After installation, perform a purge test with air.

1) The connections between branch pipes and main pipes, as well as between branch pipes themselves, should be made using threaded connections; welding is not allowed. 2) After threading, remove any burrs or debris from inside the pipes, clean them thoroughly, and then cover both ends to prevent dirt from getting in. 3) The pipes should be installed horizontally and vertically, in an orderly and aesthetically pleasing manner, without any intersections. They must be firmly fixed to the supports using pipe clamps; they cannot be buried underground but should be installed overhead. The gas supply shut-off valve is generally installed at a distance of 1–1.5 meters from the instrument’s gas supply port. 4) After installation, perform a purge test with air.