Abstract: safety valve sealing surface is too narrow and inappropriate choice of valve materials is the main reason of safety valve annular scars.
Keywords: safety valve; valve flap; opening pressure (set pressure); sealing pressure
Safety valve is widely used in boiler and pressure vessel overpressure relief device on, the performance can meet the requirements of the safe operation of boilers and pressure vessels is essential. According to the order requirements, the safety valve should be inspected regularly, at least once a year. “The steam boiler safety technology supervision order” under Article 145, for the newly installed boiler safety valve and safety valve after repair, but also to test its opening pressure (set pressure) and the sealing pressure.
China provides: steam boiler safety valve sealing test pressure to take 90% of opening pressure and reseating pressure of the lesser value. Air or other gases and water or other liquid with a safety valve sealing test pressure, when the open when the pressure is less than 0.30MPa, lower than the opening pressure 0.030MPa, when the opening pressure of 0.30 MPa greater than or equal to 90% when the opening pressure.
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Abstract: This article from the basic principles of safety valve, failure and elimination of maintenance checks were introduced, while stressing the safety valve in the pressure class of the importance of the operation of special equipment.
Keywords: pressure safety accessories special equipment; safety valve; failure and elimination; maintenance and inspection
Special equipment from the 2008 National security information that: in 2008 there were 307 incidents of special equipment, the death of 317 people and injuring 461 people, the direct economic loss of 97.8948 million yuan, while the direct result of failure or safety devices, safety accessories accident caused damage to 17, accounting for special equipment in 2008 the number of accidents from 5.5% of the total, mainly boilers, pressure vessels, pressure pipes, elevators and lifting safety device failure or corrupted.
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Keywords: boiler; safety valve; failure
Relief valve is a very important protection with the valve, widely used in various pressure vessels and piping systems, when the pressure in the system pressure exceeds the set value, it automatically opens, the surplus in the media released into the atmosphere to ensure the safety of pressure vessels and piping systems running prevent accidents, and when the pressure back down to work within the system pressure or slightly lower than the working pressure can automatically shut down. Reliable safety valve work is directly related to equipment and personal security, so attention must be given.
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1. Do not calibrate and maintain the required period
Steam Boiler Safety Technology Supervision and Pressure Vessel Safety Technology Supervision is provided that the safety valve testing system should be implemented on a regular basis, usually at least once a year tuning and calibration, while the safety valve when the check of maintenance, to ensure that sensitive and reliable.
Once the take-off safety valve in use, the downturn will be left between the spool and the valve seat layer of water damage, time, will generate a long iron. Did not take off the safety valve sealing surface through long-term use generally will leave some debris, rust and corrosive pollution generated, so that the valve sealing performance.
From the safety valve in terms of the use of management, safety valve should be conducted annually grinding, to check the inspection and maintenance combined. Were found in the extended Unchecked remains widespread.
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安全阀是一种安全保护用阀，它的启闭件受外力作用下处于常闭状态，当设备或管道内的介质压力升高，超过规定值时自动开启，通过向系统外排放介质来防止管道或设备内介质压力超过规定数值。安全阀属于自动阀类，主要用于锅炉、压力容器和管道上，控制压力不超过规定值，对人身安全和设备运行起重要保护作用。
按安全阀阀瓣开启高度可分为微启式安全阀和全启式安全阀，微启式安全阀的开启行程高度为 ≤0.05d0（最小排放喉部口径）；全启式安全阀开启高度为 ≤0.25d0（最小排放喉部口径）。
安全阀按结构形式来分，要分为垂锤式、杠杆式、弹簧式和先导式（脉冲式）；按阀体构造来分，可分为封闭式和不封闭式两种。封闭式安全阀即排除的介质不外泄，全部沿着出口排泄到指定地点，一般用在有毒和腐蚀性介质中。对于空气和蒸汽用安全阀，多采用不封闭式安全阀。对于安全阀产品的选用，应按实际密封压力来确定。对于弹簧式安全阀，在一种公称压力（PN）范围内，具有几种工作压力级的弹簧，订货时除注明安全阀型号、名称、介质和温度外，尚应注明阀体密封压力，否则按最大密封压力供货。
安全阀的安装和维护应注意以下事项：
- 各种安全阀都应垂直安装。
- 安全阀出口处应无阻力，避免产生受压现象。
- 安全阀在安装前应专门测试，并检查其官密封性。
- 对使用中的安全阀应作定期检查。