Body of reciprocating compressor
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The startup procedure for reciprocating compressors includes the following step: activate the nitrogen sealing systems for the middle vessel and the connection tank – open the shut-off valve that connects the nitrogen seal of the middle vessel to the flare, as well as the shut-off valve that connects the nitrogen seal of the middle vessel to the atmosphere, plus the vent valve of the oil collector. Could Haiyou please explain what Zhongti is and why nitrogen sealing is used?
You are compressing flammable gases, so they must be purged and displaced with nitrogen. Otherwise, the gas is compressed and heated, and danger may arise if it is air.
The intermediate body includes a crosshead assembly and a sealing packing section; nitrogen filling is used to prevent leaks of flammable or toxic substances
This is the correct answer. When transporting flammable, explosive, toxic, and harmful gases, the intermediate body must be handled in this manner.
Reply to 1# Float World Fate16: To prevent air and moisture from entering, and to avoid rusting during transportation and storage, some equipment is sealed with nitrogen upon leaving the factory. Nitrogen is an inert gas that can prevent oxygen and moisture from getting in, thus avoiding rust. When the equipment is turned on, the nitrogen must be removed because a different medium is used for operation, and that medium is then introduced in its place.
Reply to 5# zxf760718: I think your opinion differs from that of the person in post 3. Which one is correct? Please have the moderator provide an answer.
What is mentioned on the fifth floor refers to the treatment method for sealed containers at the time of leaving the factory. The compressor is manufactured in sections and does not require nitrogen sealing. Between the crosshead box and the cylinder, there is a connecting element called an intermediate sleeve. Inside this intermediate sleeve, there is an intermediate partition that prevents the gases leaking from the cylinder from coming into contact with the oil that leaks from the crosshead. Any flammable gas, when mixed with oxygen in the air in a certain volume ratio, will explode upon contact with an open flame; therefore, it must be sealed with an inert gas.
Reply to 7# Deng Baofang2010: Thank you for the answer above; it should be like that.
The nitrogen seal appears as a balance gas. This is common in the cylinder packing glands of reciprocating machines. Typically, a stuffing box has several layers, and one of the outer layers is designed for introducing nitrogen, which serves to balance any air leakage from the packing.