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A flashback arrestor or flash arrestor is a special gas safety device most commonly used in oxy-fuel welding and cutting to stop the flame or reverse flow of gas back up into the equipment or supply line and it prevents the user and equipment from damage or explosions. These devices are mainly used in different industrial processes where oxy-fuel gas mixures are handled and used. Flashback arrestors as safety products are essential to secure the workplaces and working environment. In former times there were also wet flashback arrestors used. Today the industry standard is to use dry flashback arrestors with at least two safety elements. ==Dry type== Dry flashback arrestors typically use a combination of different safety elements to stop a flashback or reverse flow of gas. This is the type that is typically found in most cutting and welding applications all over the world as they work just as effectively with any orientation, need very little maintenance, and are depending on the country or region often mandatory to be installed at the gas regulator or gas outlet/ tapping point. Depending on the application they are also often used at the torch side as an additional safety device. Flashback arrestors help prevent: * Further gas flow in the case of pressure shocks. * The entry of air or oxygen into the distribution line or single cylinders. * Flashbacks which are the rapid propagation of a flame down the hose. * Further gas flow in the event of a burnback. According to the norm EN 730-1 / ISO 5175 they include minimum two safety elements: A Gas non-return valve (NV) * The gas non-return valve prevents dangerous gas mixtures. * The gas non-return valve ensures the gas only flowing in the intended flow direction. and a Flame arrestor (FA) * The flame arrestor cools the flame down to below the ignition temperature of the gas or gas mixture. * The flame arrestor prevents flashback. In addition to these two basic safety functions a flashback arrestor can also have an: Thermal cut-off valve (TV) * The thermal cut-off valve prevents excessive temperatures. * The thermal cut-off valve closes automatically at a certain temperature and cuts off the gas flow long before the ignition temperature of the gas mixture is reached. and a Pressure-sensitive gas cut-off valve (PV) * The pressure-sensitive cut-off valve stops the gas flow in the event of pressure shocks. * Depending on the type of arrestor, the safety device can be manually reset to continue working. The flashback arrestors are suitable for most technical gases (Fuel gases) such as Acetylene, Hydrogen, Methane, Propane, Propylene and Butane as well as Oxygen and compressed air. Flashback arrestors have to be tested for gas non-return, for tightness and for gas flow by a qualified person depending on the country specific regulations. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Flashback arrestor」の詳細全文を読む スポンサード リンク
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