原文：
安全阀类的作用是防止管路或装置中的介质压力超过规定数值，从而达到安全保护的目的。 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{zd0}密封压力供货。 安全阀的安装和维护应注意以下事项： 1、各种安全阀都应垂直安装。 2、安全阀出口处应无阻力，避免产生受压现象。 3、安全阀在安装前应专门测试，并检查其官密封性。 4、对使用中的安全阀应作定期检查.

“ Safety valve and Caution ”是由提供的国际阀门新闻，译文仅供参考。另外，中国安全阀网还提供相关产品搜索： 、 、 、 、 等。

译文：
The role of safety valve type device to prevent the media pipeline or pressure exceeds the set value, so as to achieve security objectives. Protection of the safety valve is a safety valve, it's opening and closing of pieces of external force in a normally closed state, when the device or the medium pressure pipe increased exceeds the set value open automatically for discharge through the system to prevent Jiezhi within the medium pressure piping or equipment exceeds the value. Automatic valves safety valves are mainly used for boilers, pressure vessels and pipelines, the control pressure does not exceed the specified value, on personal safety and protection equipment operation play an important role. Flap valve by valve opening height can be divided into Weiqi safety valve and safety valve, safety valve opening stroke Weiqi height: ≤ 0.05d0 (minimum discharge throat diameter); safety valve to open height ≤ 0.25d0 (minimum discharge throat diameter). Divided according to the structural form of safety valve, to be divided into vertical hammer, lever, spring type, and pilot type (pulse); by body structure to points, can be divided into two closed and not closed. Closed valve that is not ruled out media leaks, all along the exit discharge to designated locations, usually used in the toxic and corrosive media. For air and steam safety valve, safety valve and more use of non-closed. The selection of products for safety valve, pressure to determine the basis of the actual seal. For the spring-loaded safety valve, in a nominal pressure (PN) within the working pressure with some level of spring, Unless otherwise indicated, when ordering safety valve type, name, medium, and temperature, the valve sealing pressure is still to be specified Otherwise, the maximum sealing pressure by supply. Installation and maintenance of safety valves should note the following: 1, various safety valve should be installed vertically. 2, the outlet valve should be no resistance, to avoid compression phenomenon. 3, safety valve should be specifically tested before installation, and check its official seal. 4, the use of safety valves should be regularly checked.