电动执行器和气动执行器实用指南（中英文）

虽然电动执行器和气动执行器各有优势，并且在不同的应用中是首选，但选择错误的执行器可能会造成严重后果。然而，在两者之间做出选择可能会让人感到困惑。本文将探讨气动执行器和电动执行器的工作原理和区别，并比较分析它们的特性，以帮助用户根据应用选择合适的执行器。

阀门执行器是一种自动化设备，用于远程控制阀门，无需人工干预。这些设备根据接收到的信号产生运动来控制阀门。执行器安装在需要控制的阀门上，取代手动杆。不同型号的执行器连接阀门和执行器的安装方式有所不同。

阀门执行器可根据其产生打开阀门所需的扭矩（或力）的方式进行大致分类。根据这种分类，最常见的两种执行器类型是电动执行器和气动执行器。电动阀门执行器利用电力产生所需的运动，而气动执行器则利用压缩空气系统。第三种类型的阀门执行器称为液压执行器，但不太常见。

While electrical and pneumatic actuators have several unique benefits and are preferred in different applications, using the wrong one for your application can have serious consequences. However, choosing between them can be quite confusing. This article explores the working principles and differences between pneumatic and electric actuators, before comparatively analyzing their features to help you choose the right one for your application.

Valve actuators are automation devices that are used to remotely control valves without human intervention. These devices generate motion to control valves based on signals received. Actuators are mounted on the valves to be controlled, replacing manual levers. The mounting features that connect a valve to an actuator vary in different actuator models.

Valve actuators are broadly classified based on how they generate the torque - or force - required to open a valve. Based on this classification, the two most prevalent types of actuators are electric and pneumatic actuators. Electric valve actuators utilize electricity to produce the required motion, while their pneumatic counterparts utilize compressed air systems. The third type of valve actuator, known as hydraulic actuators exist, but these are less prevalent.

电动执行器

Electric actuators

电动执行器将电能转换为开启或关闭阀门的力。这些设备可以使用交流电或直流电。电动阀门执行器可能配备电动机，产生旋转运动来转动阀门。这种类型的执行器用于需要旋转 90° 才能打开或关闭的四分之一回转阀门，也称为四分之一回转执行器。球阀和蝶阀执行器就属于四分之一回转执行器。

管道和流体控制系统中另一种广泛使用的电动执行器是电磁执行器。这些设备通常与阀门集成在一起，形成一个整体。

Electric actuators convert electrical energy into the force that opens or closes the valve. These devices may run on AC or DC power. Electric valve actuators may feature an electric motor that produces the rotary motion that turns the valve. This type of actuator is used for quarter-turn valves, which require a 90° turn to open or close, and are known as quarter turn actuators. Examples of quarter-turn actuators are ball and butterfly valve actuators.

Another widely used type of electric actuator in piping and fluid control systems is the solenoid actuator. These devices are typically available integrated with the valves, forming a single unit.

气动执行器

Pneumatic actuators

气动执行器利用气动元件（受控的压缩空气系统）来产生操作阀门所需的力。这些执行器可能配备一个通过压缩空气控制的活塞或隔膜。更常见的活塞式执行器包含一个位于腔室内的活塞。气动执行器可以是单作用式或双作用式。单作用执行器，通常称为弹簧复位执行器，在活塞的一侧装有加载弹簧，使阀门保持在自然位置。要打开或关闭阀门，需要在活塞的另一侧供给压缩空气，气压克服弹簧的力。

另一方面，在双作用执行器中，空气被供给到活塞的两侧。两侧之间的压力差使阀门保持在所需位置。气动执行器通常产生线性运动。然而，在诸如蝶阀执行器（需要产生旋转运动）的执行器中，使用运动转换机构 - 例如齿条和小齿轮以及拨叉机构。

Pneumatic actuator utilizes pneumatics - controlled compressed air systems - to produce the force required to operate a valve. These actuators may feature a piston, or diaphragm, that is controlled via compressed air. The more ubiquitous piston-featuring variety contains a piston housed in a chamber. Pneumatic actuators may be single-acting or double-acting. Single-acting actuators, more commonly known as spring return actuators, feature a loaded spring on one side of the piston that keeps the valve in its natural position. To open or close the valve, pressurized air is supplied on the other side of the piston, and the air pressure overcomes the force of the spring.

On the other hand, in double-acting actuators, the air is supplied to both sides of the piston. The difference in pressure between the two sides keeps the valve in the desired position. Pneumatic actuators typically produce linear motion. However, in actuators such as butterfly valve actuators (which are required to generate rotary motion), motion conversion mechanisms - such as rack and pinion, and scotch yoke mechanisms - are used.

电动执行器和气动执行器之间的选择

Choosing between an electric and a pneumatic actuator

电动和气动阀门执行器在不同应用中各有优势。为了选择适合应用的执行器，需要分析这些执行器的一些因素和特性。下文将探讨其中一些因素和特性。

Both electric and pneumatic valve actuators have specific advantages in different applications. To choose the right one for your application, certain factors and characteristics of these actuators have to be analyzed. Some of these factors and characteristics are explored below.

1. 精度/Precision

精度是指需要在部分开启或关闭位置操作以允许精确量介质流过的阀门。电动和气动执行器均可提供精确的控制。然而，当依赖气动执行时，可能需要在气动操作设备（例如控制阀）上附加电-气定位器，以实现化工生产等应用中所需的高精度控制。

Precision is considered for valves that need to operate in partially open or closed positions to allow an exact amount of media to flow through. Both electric and pneumatic actuators provide precise control. However, when relying on pneumatic actuation, the inclusion of an electro-pneumatic positioner may be required as an accessory on a pneumatically operated device such as a control valve to achieve the high precision control necessary in applications such as chemical production.

2. 力的范围/Force range

气动执行器单位侧向力/扭矩显著高于电动执行器。对于涉及大型阀门或高工作压力阀门的应用，气动执行器是更好的选择。

Pneumatic actuators provide a significantly higher force/torque per unit side than their electric counterparts. For applications that involve a large valve or a valve with high operating pressure, pneumatic actuators are the better option.

3. 速度/Speed

在防洪等特定应用中，执行速度是一个至关重要的考虑因素。与精度一样，电动执行器和气动执行器都可以快速执行。然而，气动执行器反应更快，占空比更高。此外，气动执行器的运行速度可调。

Speed of actuation is a crucial consideration in specific applications such as flood control. Like with precision, both electric and pneumatic actuators can be fast. However, a pneumatic actuator reacts faster and has high duty cycles. Furthermore, the operating speeds of pneumatic actuators are adjustable.

4. 使用寿命/Lifespan

气动执行器组件较少，因此比电动执行器更易于维护，使用寿命更长。电动执行器包含多个部件，可能需要定期维护。虽然执行器单元可能不需要维护，但其他部件（例如空气压缩机和FRL（过滤器、调节器和润滑器））可能需要更频繁的维护。

Pneumatic actuators have fewer components. Therefore, they are easier to maintain and have a longer lifespan than electrical actuators, which have several parts that may require regular maintenance. However, while the actuator unit may not require maintenance, other components such as the air compressor and the FRL (Filter, Regulator, and lubricator) may require more frequent maintenance

5. 成本/Cost

气动阀门执行器的设计比电动执行器更简单，因此其成本低于电动执行器。然而，如果考虑到配套气动系统的成本，气动执行系统的总成本就会增加。通过在同一个压缩空气供应系统中安装多个执行器，可以显著降低这一成本。

The design of pneumatic valve actuators is more straightforward than that of their electric counterparts, and so these actuators cost less than electric counterparts. However, when the cost of the accompanying pneumatic system is considered, the overall cost of a pneumatic actuation system increases. This cost can be significantly reduced by setting up numerous actuators with the same pressurized air supply system.

6. 故障安全/Fail safe

在执行器故障可能造成严重后果的应用中，执行器需要配备故障安全机制。在气动执行器中安装故障安全装置更简单、更经济。弹簧复位式气动阀门执行器具有固有的故障安全机制，当发生故障时，弹簧力会自动将阀门返回到其自然位置。

In applications where a failure in the actuator can have severe consequences, the actuator needs to have a fail-safe mechanism. A fail-safe is easier and cheaper to install in pneumatic actuators. Spring return pneumatic valve actuators feature a natural fail-safe mechanism, as the force of the spring will automatically return the valve to its natural position in the case of a failure.

7. 危险条件/Hazardous conditions

电动执行器通常包含精密部件，在危险条件下可能无法正常工作。此外，这些执行器需要获得多项认证才能被认定适用于特定环境。电动执行器需要高水平的防护，以防高温高压、灰尘和潮湿。而气动执行器则非常坚固，能够承受比电动执行器更高的压力和温度。

Electric actuators often feature delicate components that may not function correctly in hazardous conditions. Furthermore, these actuators require numerous certifications in order to be deemed suitable in certain environments. Electric actuators need a high level of protection against high temperatures and pressures, dust, and moisture. On the other hand, pneumatic actuators are quite rugged and can withstand higher pressures and temperatures than their electric counterparts.

结论

Conclusion

气动执行器和电动执行器都是高效且功能强大的自动化设备，广泛应用于各行各业。然而，它们各自拥有独特的特性，使其在不同应用中脱颖而出。为了选择最适合应用的执行器，请仔细考虑上述因素。

Both pneumatic and electric actuators are efficient and highly functional automation devices that are employed across various industries. However, they each possess unique characteristics that make them preferable in different applications. To select the best one for your application, carefully consider the above-listed factors.