什么是安全阀以及安全阀的用途是什么？（中英文）

什么是安全阀以及安全阀的用途是什么？

What is a safety valve and what is the purpose of a safety valve?

安全阀可以被视为减压或卸压装置。当内部流体压力过高时，该阀门将打开，以防止系统损坏。这些阀门通常用于燃气和蒸汽管线。在未受保护的压力容器或系统中，如果压力水平超过安全压力水平，则可能对工厂和人员造成灾难性影响。安全泄压阀的主要目的是保护加压系统免受超过其设计压力限制的影响。这些阀门设计用于自动排出任何承压系统中的气压或液体，从而防止压力过大并保护工厂和人员。为了实现这一切，应确保安全阀的尺寸、选择、安装正确。

A safety valve can be considered as a pressure reducing or pressure removing device. When there is any excessive internal fluid pressure then this valve would open so that the damage in the system can be prevented. These valves are commonly used in gas and steam lines. In an unprotected pressure vessel or a system if the pressure level exceeds the safe pressure level, then there could be catastrophic effects on both plant and personnel. The major purpose of a safety relief valve is to protect any pressurized system from the effects of exceeding its design pressure limit. These valves are designed to automatically discharge gas pressure or liquid from any pressure-containing system and thus it prevents excessive pressure and protects plants and personnel. In order to fulfill all this, a safety valve should be properly sized, selected, installed, and maintained.

安全阀有哪些特点？

What are the characteristics of the safety valve?

• 这些阀门主要用于可压缩流体，例如蒸汽或其他气体

• 只有当压力降至正常压力时，安全阀才会关闭，否则它将保持全开状态。

• 在安全阀中，进口比出口更小

• 安全阀采用外部阀杆，位于阀体顶部，用作操作检查。

• These valves are mostly used for compressible fluids such as steam or other gases

• Only if the pressure drops to the normal pressure, the safety valve would close otherwise it would stay fully open.

• In a safety valve, the inlet port is smaller when compared to the discharge port

• An external valve lever is used in the safety valve and it can be seen at the top of the valve body, which is used as an operational check.

安全阀和溢流阀有什么区别？

What is the difference between the safety valve and the relief valve?

溢流阀会释放液体或按比例打开阀门，以便维持一定的系统压力。如果是安全阀，它会立即快速升压和减压。主要区别在于容量和设定点。溢流阀会在超压情况下释放压力，它有一个操作器，可以发出控制信号来打开阀门。安全阀无需操作员的帮助即可操作。当流体压力增加时，溢流阀逐渐打开，而当达到设定压力时，安全阀完全打开。如果系统达到开启压力，安全阀将完全打开，并且安全阀没有像溢流阀那样的半开或半开位置。

A relief valve would release the liquid or open the valve in a proportional manner so that it can maintain some system pressure. In the case of a safety valve, it would quickly lift and reduce the pressure instantly. The major difference is in the capacity and set point. The relief valve would relieve pressure in case of overpressure conditions, it has an operator that would give a control signal to open the valve. Safety valves operate without the help of an operator. The relief valve would open gradually as the fluid pressure increases while the safety valve opens fully when the set pressure is reached. The safety valve will open fully if the system achieves the opening pressure and there is no half or semi-open position for a safety valve like the relief valve.

如何选择安全阀

How to select a safety valve

• 按介质分（空气、气体、蒸汽、液体）

• 设定压力、爆破压力和泄压

• 根据应用所需容量

• 必须考虑温度、背压、腐蚀性介质或环境等因素

• 根据经营特点

• 正常工作压力是系统在满负荷情况下的工作压力

• 最大允许工作压力，是正常工作条件下存在的最大压力

• 设定压力，即阀门开始提升的压力

• 过压，是超过设定压力的压力，阀门在此压力下开始升程

• According to the media (air, gas, steam, liquid)

• Set pressure, popping pressure, and relieve pressure

• According to the required capacity for the application

• Factors such as temperature, back pressure, and corrosive media or environment must be considered

• According to the operational characteristics

• Normal working pressure is the operating pressure of the system under full load

• Maximum allowable working pressure, it is the maximum pressure existing normal operating conditions

• Set pressure, it is the pressure at which the valve starts to lift

• Overpressure, it is the pressure that exceeds the set pressure and the valve starts to lift in this pressure

什么是安全泄压阀

What is a safety relief valve

安全泄压阀广泛应用于大多数工艺设备中。这些阀门可用作泄压阀或安全阀。这些阀门可在气体和蒸汽系统中用作安全阀，也可在液体系统中用作泄压阀。

Safety relief valves are widely used in most of the process equipment. These valves can be used as either a relief valve or a safety valve. These valves can be used in gas and vapor system as safety valves and they can also be used as a relief valve in a liquid system.

压力安全阀由哪些部件组成

What are the components of a pressure safety valve

上图为常规压力安全阀的主要部件

盖子 – 它是安全阀的顶部部分，覆盖调节螺钉，调节螺钉可以通过螺纹或螺栓连接到阀盖上。

阀盖 – 它是阀门的中间部分，里面装有阀杆、弹簧、弹簧按钮和导板。该装置可以是开放式或封闭式的。

主体 – 它是最底部的部分，包含阀瓣支架、阀瓣、喷嘴泄压环和锁紧螺母。

调节螺钉 – 该装置用于在规定的设定压力下校准压力安全阀

阀杆 – 该装置正确对齐组件并将弹簧的动力传递到阀瓣组件

弹簧和弹簧按钮 – 弹簧有助于保持阀门关闭，弹簧按钮可以均匀分布弹簧力。

提升杆 – 提升杆用于手动泄压

阀瓣和阀瓣支架 – 阀瓣是会受到过程压力影响的设备，它们容易受到磨损、腐蚀和点蚀

喷嘴 – 喷嘴是过程流体进入阀门的入口。有多种类型的喷嘴可用，它们有全螺纹可拆卸式、半螺纹可拆卸式、半焊接在阀体上、半压制式可拆卸式。

The above figure shows the major parts of the conventional pressure safety valve

Cap – it is the top part of the safety valve, which covers the adjustment screw this could be threaded or bolted to the bonnet.

Bonnet – it is the middle part of the valve and it houses the stem, spring, spring buttons, and guide plate. This device could be open or closed type.

Body – it is the bottom-most portion and it encloses disc holder, disc, nozzle blow-down ring, and locking nut.

Adjustment screw – This device is used for the calibration of pressure safety valve in a specified set pressure

Stem – This device properly aligns the components and transmits the power of the spring to the disc assembly

Spring and spring buttons – Spring will help to keep the valve closed and the spring button can uniformly distribute the spring force.

Lift lever – Lift lever is used for manual pressure relief

Disc and disc holder – Disc is the device that would be affected by process pressure and they are vulnerable to galling, erosion, and pitting

Nozzle – Nozzle is the entrance by which the process fluid enters into the valve. There are many types of nozzles available they are fully threaded and removable, semi threaded and removable, semi, welded in the valve body, semi pressed and removable.

安全阀是如何构造的以及构造所用的材料有哪些

How safety valves are constructed and what are the materials used for the construction

有时安全阀必须在低温、腐蚀性流体等恶劣条件下工作，因此采用特殊材料进行构造。压力阀的承压部件大多采用青铜、铸铁或不锈钢制成。青铜用于小型螺纹阀门，这些阀门用于低和中级行业。高压阀门采用铸钢制成。

安全阀的内部部件，如作为运动部件的主轴或导轨，必须采用不易腐蚀的材料制成。阀座和阀瓣必须能够耐腐蚀，因此其结构采用不锈钢。有时，喷嘴盘采用哈氏合金或蒙乃尔合金等特殊合金制成。

Sometimes safety valves must operate under severe conditions like low temperatures, corrosive fluids, etc. So special materials are used for the construction. Mostly the pressure containing components of the pressure valves are constructed by using bronze, cast iron, or stainless steel. Bronze is used for small screwed valves and these valves are used for the low and medium sectors. Higher pressure valves are constructed by using cast steel.

The internal components of safety valves such as spindle or guides which is the moving part must be constructed by using materials that will not easily corrode. The seats and discs must be able to resist corrosion, so stainless steel is used for their construction. Sometimes nozzle discs are constructed by using special alloys such as Hastelloy or monel.

系统中如何发生超压以及系统中出现的严重状况

How excess pressure takes place in a system and How severe condition arises in a system

• 瞬态压力波动

• 工厂火灾暴露

• 热交换器管故障

• 环境温度变化

• 冷却系统故障会导致蒸汽膨胀

• 化工厂中不受控制的放热反应

• Transient pressure surge

• Plant fire exposure

• Heat exchanger tube failure

• Ambient temperature changes

• Failure of the cooling system and it would cause the vapor to expand

• Uncontrolled exothermic reactions in a chemical plant

安全泄压阀如何工作

How does a safety relief valve work

如果压力升至系统中的设定压力以上，阀瓣将开始升离其底座。弹簧将开始压缩，弹簧力也会增加。因此，只有当压力再次增加时才会发生升程，之后才会发生通过阀门的流动。超压是安全阀以其额定容量泄放之前所需的额外压力升高。超压取决于设定压力和特定应用的标准。安全阀中的阀瓣的布置方式是，压力稍微高于设定压力就会导致阀门打开。当系统中的压力达到安全水平时，阀门将返回到关闭位置。

If the pressure rises above the set pressure in a system, the disc will begin to lift off its seat. The spring will start to compress and the spring force also increases. So the lift will happen only if the pressure is increased again and after that, the flow through the valve occurs. Overpressure is the additional pressure rise needed before the safety valve will discharge at its rated capacity. Overpressure is dependent upon the set pressure and the standard for the particular application. The disc in the safety valve is arranged in a way that a slight increase in pressure than the set pressure could cause the valve to open. When the pressure reaches a safe level in the system the valve would return to its closed position. The disc is arranged for rapid opening in order to achieve this most safety valves have a secondary chamber formed by a shroud, skirt, or hood around the outside diameter of the disc.

安全阀有哪些类型

What are the types of safety valves

常规安全阀

Conventional safety valve

这种类型的阀门有一个弹簧外壳，该弹簧外壳通向阀门的排放侧。阀门的操作特性受阀门背压变化的影响。这是较简单的安全阀类型，用于背压且非常小。

This type of valve, it has a spring housing that is vented to the discharge side of the valve. The operational characteristic of the valve is affected by the changes in the backpressure of the valve. This is the simplest type of safety valve and they are used in the backpressure and are very small.

平衡式安全阀

Balanced safety valve

平衡安全阀能够借助波纹管或其他设备消除背压影响。这些阀门是弹簧加载的安全泄压阀，当排气系统中的累积背压百分比允许超过适用于安全阀的超压百分比时安装这些阀门。平衡式安全阀有活塞式和波纹管式两种。

Balanced safety valves are capable to remove back pressure effects with the help of bellows or other equipment. These valves are spring-loaded safety relief valves, these valves are installed when the percentage build-up back pressure in the exhaust system is allowed to exceed the percentage overpressure applicable to the safety valve. Balanced safety valves are of two types, piston type, and bellow type.

先导式安全阀

Pilot operated safety valves

先导式安全阀是一种泄压阀，其主要泄压装置是带有自力式辅助泄压阀。泄压装置由辅助泄压阀控制。先导式安全阀有隔膜式和活塞式两种类型。隔膜式用于低压应用。就活塞式阀门而言，它有一个使用活塞形关闭装置的主阀和一个外部先导阀。

A pilot-operated safety valve is a pressure relief valve, in which the major relieving device is with a self-actuated auxiliary relief valve. The relieving device is controlled by the auxiliary relief valve. Pilot operated safety valves are of two types they are diaphragm and piston type. The diaphragm type is used for low-pressure applications. In the case of the piston-type valve, it has a main valve that uses a piston-shaped closing device and an external pilot valve.

基于喷嘴的安全阀类型

Types of safety valves on the basis of the nozzle

全喷嘴式安全阀

Full nozzle safety valve

在这种类型中，喷嘴是法兰的凸面部分，用于释放液体和蒸汽，并且还具有封闭的阀盖。

In this type the nozzle is the raised face portion of the flange, it is used for liquid and vapor relief and also has a closed bonnet.

半喷嘴式安全阀

Semi nozzle safety valve

这些阀门还用于液体和蒸汽释放。喷嘴由拧入基座连接的嵌件组成，可以是法兰连接、焊接端连接或螺纹连接

These valves are also used for liquid and vapor relief. Nozzle consist of insert screwed into base connection can be flanged, weld ended or screwed

底座喷嘴式安全阀

Base nozzle safety valve

在这种类型中，喷嘴由阀门的底座形成，大多数阀门具有螺纹连接，但也有法兰或焊接端，这些阀门在百分之二十五的过压下完全打开，并且具有封闭的阀盖。

In this type, the nozzle is formed from the base of the valve, mostly these valves have a screwed connection but they are also available in flanged or weld-ended and these valves would fully open at twenty-five percent overpressure and they have closed bonnet.

什么是电动安全阀

What is an electromatic safety valve

该阀是压力开关启动的安全阀，它被设置为在特定压力下提升，但常规安全阀仅在压力累积后才会提升。

This valve is a pressure switch initiated safety valve and it is set to lift on a particular pressure but a regular safety valve will only lift after the accumulation of pressure.

安全阀的安装方法

How to install the safety valve

在工厂调试过程中，阀门会被提升，如果有碎片或污垢，就会损坏阀座。因此，在安装安全阀之前应冲洗系统，以免异物通过阀门。阀门必须安装在不会积聚灰尘和碎屑的地方。安全阀应垂直安装在压力容器内。阀门入口管道的压降不得超过设定压力的百分之三。在蒸汽应用中，安全阀必须安装在蒸汽管道上方。不宜安装在下方，因为蒸汽会凝结，充满管道，弄湿安全阀阀座的上游侧。

During the plant commissioning procedure, the valve would be lifted and there would be seat damage if there is debris or dirt. So the system should be flushed out before installing a safety valve if done so foreign matter won’t pass through the valve. The valve must be installed in a place where dirt and debris must not collect. The safety valve should be mounted vertically in a pressure vessel. The pressure drop in the valve inlet piping must not exceed more than three percent of the set pressure. In steam applications, the safety valve must be installed above the steam pipe. It should not be installed below because, the steam will condense, fill the pipe, and wets the upstream side of the safety valve seat.

安全阀的故障排除和维护方法

How to troubleshoot and maintain a safety valve

系统工作压力不得太接近阀门设定压力。安全阀的工作压力和设定压力之间需要有百分之五到百分之十的差异。安全阀不得设置低于15PSI。根据容器能够承受的压力，它应该在20-25的范围内。安全阀不能水平安装，安全阀只能在垂直位置工作，否则将无法正常工作。安全阀必须存放在干燥的环境中并免受天气影响，直到安装前才应将其从垫木或板条箱中取出。阀门必须保持入口朝下，以防止损坏。安全阀必须进行年度定期检查。如果安全阀安装在室外，那么它们会暴露在风中，空气、雪、污垢，因此必须采取某些安全措施。安全阀的入口颈部和阀体必须绝缘，并且绝缘的外部部分必须防风雨。安全阀必须需要某些备件，它们是平坦的研磨板、高温润滑剂、粒度研磨剂。

The system operating pressure must not be too close to the valve set pressure. A safety valve needs a five to ten percent difference between the operating and set pressure. Safety valves must not be set to less than 15PSI. It should be in the range of 20-25 according to the pressure that the vessels could handle. We must not install safety valves horizontally safety valves are meant to work only in a vertical position, if not it won’t work properly. Safety valves must be stored in a dry environment and protected from weather, they should not be removed from the skids or crates until immediately prior to installation. The valve must be kept in a way that the inlet is down so that damage can be prevented. Safety valves must be subjected to an annual periodic inspection. If the safety valves are installed outdoor then they would be exposed to wind, air, snow, dirt, so certain safety features must be done. The inlet neck of the safety valve and the valve body must be insulated and the exterior part of the insulation must be weatherproof. Certain spares must be needed for the safety valve they are flat lapping plate, high-temperature lubricant, a lapping compound of grit size.

安全阀泄漏的原因有哪些

What can be the cause of safety valve leakage

如果底座表面有污垢或水垢，则可能会发生泄漏。抬起控制杆即可清除污垢。泄漏大多是在初次制造和测试后造成的，这种问题是由于运输过程中的损坏而产生的。如果安装不当，可能会导致阀门泄漏。聚四氟乙烯涂层或管道涂料会导致阀门泄漏。因此，安装阀门时必须进行检查，必须确保螺纹不会太低，如果螺纹进入阀门，它会粘在阀座表面上并可能导致泄漏。

Leakage can happen if there is dirt or scale sitting on the seating surface. Lifting of the lever can remove the dirt. Mostly the leakage can be caused after the initial manufacture and test, this problem occurs from the damage during transit. If the installation is not proper it can cause valve leakage. Teflon coat or pipe dope can cause valve leakage. So it must be checked when the valve is installed we must ensure that it is not too low on threads if this gets into the valve it can stick on the seating surface and can cause a leak.

安全阀的应用有哪些

What are the applications of safety valves

发电厂和热交换器循环

减压及空气系统

炼油厂和造纸厂

水、空气增压系统

化工厂和制药厂

离岸应用

蒸汽及工业锅炉系统

Power plants and heat exchangers cycle

Pressure reduction and air system

Refineries and paper mills

Pressure booster system of water and air

Chemical and pharmaceutical plants

Offshore application

Steam and industrial boiler system

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