1. According to its overall structure, it can be divided into heavy hammer lever type, spring type and pulse type.

(1) 重锤杠杆阀

(1) Heavy hammer lever safety valve

? 重锤杆阀使用重锤和重锤杆来平衡作用在阀盘上的力。根据杠杆原理，它可以通过增加杠杆使用小砝码来获得大的力，并通过移动砝码的位置(或改变砝码的重量)来调节阀的开启压力。适用于高温场合。

? The heavy hammer rod safety valve uses a heavy hammer and a heavy hammer rod to balance the force acting on the valve disc. According to the lever principle, it can increase the lever and use a small weight to obtain a large force, and adjust the opening pressure of the safety valve by moving the position of the weight (or changing the weight of the weight). Suitable for high temperature applications.

(2) 弹簧微开阀

(2) Spring slightly open safety valve

弹簧微开阀利用压缩弹簧的力平衡作用在阀盘上的力。可以通过转动螺旋弹簧上的调整螺母来调整螺旋弹簧的压缩。利用这种结构，可以根据需要校正阀的开启(设定)压力。它可用于移动式压力容器。

The spring slightly open safety valve uses the force of the compression spring to balance the force acting on the valve disc. The compression of the coil spring can be adjusted by turning the adjusting nut on the coil spring. With this structure, the opening (set) pressure of the safety valve can be corrected as needed. It can be used for mobile pressure vessels.

(3) 脉冲阀

(3) Pulse safety valve

脉冲阀由主阀和辅助阀组成。辅助阀的脉冲动作驱动主阀的动作。其结构复杂。通常仅适用于排放量大的锅炉和压力容器。

Pulse safety valve consists of main valve and auxiliary valve. The pulse action of the auxiliary valve drives the action of the main valve. Its structure is complex. Generally, it is only applicable to boilers and pressure vessels with large safe discharge.

2.根据介质排放方式的不同，可分为全封闭式、半封闭式和开放式。

2. According to different medium discharge modes, it can be divided into fully closed, semi closed and open.

(1) 全闭式阀

(1) Fully closed safety valve

当全封闭阀排气时，所有气体通过排气管排出，介质不能外泄。主要用于含有有毒、易燃气体的容器。

When the fully closed safety valve exhausts, all gases are discharged through the exhaust pipe, and the medium cannot leak out. It is mainly used for containers containing toxic and flammable gases.

(2) 半闭式阀

(2) Semi closed safety valve

半闭式阀排出的部分气体通过排气管，部分气体从阀盖和阀杆之间的间隙泄漏。它主要用于介质为不会污染环境的气体的容器中。

Part of the gas discharged from the semi closed safety valve passes through the exhaust pipe, and part of the gas leaks from the gap between the valve cover and the valve stem. It is mainly used in containers whose medium is gas that will not pollute the environment.

(3) 打开阀

(3) Open the safety valve

开启式阀的阀盖打开，将弹簧室与大气连接，有利于降低弹簧温度。主要适用于以蒸汽为介质、不污染大气的高温气体的容器。

The valve cover of the open safety valve is opened to connect the spring chamber with the atmosphere, which is conducive to reducing the spring temperature. It is mainly applicable to the container of high-temperature gas with steam as the medium and does not pollute the atmosphere.

? 3.根据作用原理可分为直接作用型和间接作用型。

? 3. According to the action principle, it can be divided into direct action type and indirect action type.

(1) 直接作用阀

(1) Direct acting safety valve

直接作用阀是在工作介质的直接作用下开启的，即依靠工作介质的压力来开启阀门，克服加载机构对阀盘施加的机械载荷。该阀结构简单，动作迅速，可靠性好。但由于结构载荷的限制，其载荷有限，不能用于高压和大直径场合。

The direct acting safety valve is opened under the direct action of the working medium, that is, the valve is opened by relying on the pressure of the working medium to overcome the mechanical load imposed by the loading mechanism on the valve disc. The safety valve has the advantages of simple structure, rapid action and good reliability. However, due to the limitation of structural load, its load is limited and can not be used in high pressure and large diameter occasions.

(2) 非直接作用阀

(2) Non direct acting safety valve

? 这种阀可分为先导式阀和带动力辅助装置的阀。

? This safety valve can be divided into pilot safety valve and safety valve with power auxiliary device.

?先导阀由先导阀排出的介质驱动或控制。适用于高压、大直径场合。这种阀的缺点是其可靠性与主阀和先导阀有关。其动作不如直动式阀快速可靠，结构复杂。

? The pilot relief valve is driven or controlled by the medium discharged from the pilot valve. Suitable for high pressure and large diameter occasions. The disadvantage of this safety valve is that its reliability is related to the main valve and pilot valve. Its action is not as fast and reliable as direct acting safety valve, and its structure is complex.

?带动力辅助装置的阀是在低于正常开启压力的情况下，借助动力辅助装置迫使阀开启。阀适用于开启压力非常接近工作压力的场合，或需要定期开启阀进行检查或吹走粘合剂和冻结介质的场合。同时，它还提供了在紧急情况下强行打开阀的方法。

? The safety valve with power auxiliary device forces the safety valve to open with the help of power auxiliary device under the condition of lower than the normal opening pressure. The safety valve is suitable for occasions where the opening pressure is very close to the working pressure, or occasions where it is necessary to open the safety valve regularly for inspection or blow away the adhesive and frozen medium. At the same time, it also provides a method of forcibly opening the safety valve in an emergency.