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Oxygen Valve Working Principle

Ningbo Fenfa Valve Co.,Ltd | Updated: Sep 07, 2017

Oxygen valves, also known as oxygen special valves, are specially designed for oxygen pipe network special valves. Widely used in steel, metallurgy, petroleum, chemical and other oxygen engineering pipe network. Oxygen valve in addition to the function of a common valve has its own characteristics. From the oxygen valve material selection is divided into two categories: one is the use of cast silicon brass for the valve body, bonnet, valve petals; the other is the choice of high quality stainless steel for the valve body, Timber.

Oxygen is one of the most widely distributed elements in nature. The volume of oxygen in the air is 20.93% by volume. Oxygen at room temperature and pressure is colorless and transparent, tasteless, odorless gas, slightly heavier than the air. At atmospheric pressure, when cooled to -182.96 ° C, oxygen condenses into sky blue, transparent, easily flowing liquid; when the temperature drops to -218.4 ° C, it condenses into blue solid crystals. Oxygen is very lively chemical properties, is a strong oxidizing agent and combustion agent, which in addition to gold, silver and inert gas helium, neon, argon, krypton and so on in the general situation does not occur, and other substances can be combined to produce oxides. The degree of oxidation depends on the concentration and pressure of oxygen. If the oxidation is carried out in pure oxygen, the process is very intense and a large amount of heat is released. (Such as metal in the oxygen reaction, if the increase in oxygen purity and pressure will significantly increase the oxidation reaction, metal ignition with oxygen pressure increases), oxygen and combustible gases (acetylene, hydrogen, methane, etc.) mixed in a certain proportion , The case of fire will explode. Oxygen is compressed, in the course of transport, if there is grease, iron oxide or small particles of combustion (coal, carbon or organic fiber) exists, with the air movement and the wall or the body friction, impact, will produce A lot of friction heat, resulting in pipes, machine burning. Or because the valve in the pipeline caused by an emergency explosion. Based on these special properties of oxygen, the pipes in the oxygen piping, valve fittings, litter and all materials in contact with oxygen must be strictly rusted, purged and degreased before installation.

Pipeline degreasing

⑴ degreasing agent

Industrial use of carbon tetrachloride, distillation of alcohol and industrial dichloroethane can be used as a degreasing agent solvent.

Carbon steel, stainless steel and copper pipes, pipe fittings are suitable for industrial use of carbon tetrachloride. Carbon tetrachloride and dichloroethane are toxic, in use must have anti-virus measures. Dichloroethane and distilled alcohol is a flammable and explosive material, degreasing work site should be strictly prohibited fireworks, to comply with the relevant provisions of arson.

⑵ degreasing test

After degreasing, the skim quality test should be carried out according to the design requirements. When the design is not specified, the method and the eligibility criteria for degreasing quality inspection are as follows:

① Wipe the inner wall of the oxygen valve passage with a clean, dry white filter paper. There should be no grease on the paper.

② with ultraviolet light irradiation, degreasing surface should be no purple blue fluorescence.

Oxygen dedicated valve selection

① working pressure greater than 0.1MPa of the valve, is strictly prohibited the use of gate valve, should be used cut valve or ball valve.

② oxygen valve material using all stainless steel or copper-based alloy.

③ oxygen valve seal packing should be used PTFE.

④ oxygen pipe on the flange, should be selected according to the current national JB standard.

⑤ oxygen pipe on the flange gasket should be used to soften aluminum annealing, annealing softened copper.

Oxygen dedicated valve connection

① Oxygen pipeline connection, should be used welding, but with the equipment, the valve connection can be used flange, threaded connection. Silk connector, should be used lead oxide, water glass or PTFE film as a filler, is strictly prohibited with lead-coated linen or cotton, or other oil-containing materials.

② Oxygen pipeline should be removed from the static grounding device. The plant piping may have a grounding device at every 100 to 100 m of the pipe without branch piping at the branch of the pipeline and into and out of the building. Directly buried pipeline can be buried before and after the ground once the ground; workshop internal pipeline, with the workshop of the electrostatic trunk connection, grounding resistance should be consistent with the specification. When the resistance between each pair of flanges or threaded joints over 0.03Ω, should be set up across the wire. Do not apply to a pipe with a protective plate.

③ Oxygen pipeline elbow, fork should not be installed immediately downstream of the valve, the downstream side of the valve should not be less than 5 times the length of the pipe diameter straight pipe.

Oxygen dedicated valve acceptance

① oxygen valves, pipes and fittings, etc., should be no cracks, scales, such as slag. Contact the surface of the oxygen must be completely removed glitches, welding, welding slag, sticky sand, rust and other combustible materials, etc., to keep the inner wall smooth and clean, pipe rust should be carried out until the appearance of color.

② oxygen valves, fittings, gaskets must be defatted, the manufacturer has been skimmed, and a reliable sealed packaging can no longer degrease.

③ Pipes, valves, fittings, etc. in the installation process and after installation, should take effective measures to prevent contamination by the oil.

Standard for Oxygen Special Valves

① design and manufacture by GB12237, GB12235

② flange connection size in line with GB9115

③ structure length by GB12221

④ degreasing and inspection by HGJ202

⑤ test and test by GB / T13927

⑥ material in line with GB12225, GB12230

Note: The above requirements of the oxygen valve also applies to acetylene, hydrogen.

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