Explosion-proof Type and Principle of Explosion-proof Electric Actuators

电动执行器被使用在十分恶劣的、往往有很多易燃易爆气体混合物的工作环境中，因此对电动执行器的防爆功能有着很高的要求，这样才能保证电动执行器使用的安全性和有效性。本文以中英合资天蝶阀门生产的防爆型电动执行器为例，分析如何进行智能型电动执行器的防爆结构设计。

Electric actuators are used in very harsh working conditions,often with a lot of flammable and explosive gas mixture,therefore, the explosion-proof function of the electric actuator is highly required, so as to ensure the safety and effectiveness of the electric actuator.Taking the explosion-proof electric actuator produced by the Sino-British joint venture Tandy Valve as an example, this paper analyzes how to design the explosion-proof structure of the electric actuator.

1、隔爆型电动执行器“d”

1. Flameproof electric actuator " d "

一种具有隔爆外壳的电动执行器。隔爆外壳能承受已进入外壳内部的可燃性混合物内部爆炸而不损
坏，并且通过外壳上的任何接合面或结构孔不会引燃一种或多种气体或蒸气所形成的外部爆炸性
环境的电动执行器外壳。

An electric actuator with a flameproof enclosure. The flameproof enclosure can withstand an explosion inside a combustible mixture that has entered the outer shell without damaging it bad, and does not ignite the external explosion of one or more gases or vapors through any joint or structural holes on the housing electric actuator housing for the environment.

2、增安型电动执行器“e”

2.Increased safety electric actuator "e"

一种对在正常运行条件下不会产生电弧、火花的电动执行器采取一些附加措施以提高其安全程度，防止其内部盒外部部件可能出现危险温度、电弧或火花的电动执行器。

An electric actuator that does not generate electric arc and spark under normal operating conditions is adopted to take some additional measures to improve its safety, defense
An electric actuator that prevents dangerous temperatures, arcs, or sparks from appearing on external parts of its internal box.

3、本质安全型电动执行器“i”

3.Intrinsically Safe Type Electric Actuators "i"

本质安全通常指某个系统，而不是指某一个设备。人们通常说一个变送器或传感器或传感器是本质
安全时，这是一种简化说法，实际上本质安全指变送器或传感器经电缆与关联设备（安全栅等）组成的本质安全系统。

Intrinsic safety usually refers to a system and not to a device. People usually say that a transmitter or sensor or sensor is essential.When secure, this is a simplified term, in fact inherently safe refers to an essential safety system consisting of a transmitter or sensor via cable and associated equipment (security grids, etc.).

本质安全电路

Intrinsically safe circuit

本质安全电路指在规定条件（包括正常工作和规定的条件）下产生的任何火花或任何热效应均不能点燃规定的爆炸性气体环境的电路。

Intrinsic safety circuit means any spark or any thermal effect produced under specified conditions (including normal working and prescribed conditions) shall not ignite the specified explosive gas environment.

本质安全设备

Intrinsic safety equipment

本质安全设备指在其内部的所有电路都是本质安全电路的电动执行器。

Intrinsic safety equipment means that all the internal circuits are essential safety circuits of electric actuators.

关联设备

Associated equipment

关联设备指内部装有本质安全电路和非本质安全电路，且结构使非本质安全电路不能对本质安全电路产生不利影响的电动执行器。关联设备在危险场所安装使用时， 应加其他形式防爆外壳保护，例如隔爆型、正压型等；在安全场所安装使用时，其外壳可选用一般型。在本质安全系统中与本质安全设备有电气连接，接口部分有限压， 限流环节（限制能量）的电动执行器可认为是关联电动执行器，如齐纳安全栅、隔离式安全栅、本质安全电源、光电隔离接口电器等。

The device is an electric actuator with intrinsic safety circuit and non-essential safety circuit, and its structure prevents the non-essential safety circuit from having an adverse effect on the intrinsic safety circuit. Other forms of explosion-proof enclosure protection should be added when the associated equipment is installed and used in dangerous places, such as flame-proof type, positive-pressure type, etc. For installation and use in a safe place, the housing may be of the general type. Motor actuators with electrical connections to intrinsic safety equipment, limited voltage in the interface part, and limited current limiter ( limited energy) can be considered to be associated with an electric actuator in an intrinsic safety system, Such as Zener Safety Grid, Isolated Safety Grid, Intrinsic Safety Power Supply, Photoelectric Isolation Interface Electrical Equipment, etc.

4、正压型电动执行器“p”

4.Positive Pressure Type Electric Actuators "p"

一种通过保持内部保护气体的压力高于周围爆炸性环境压力的措施来达到安全的电动执行器。

An electric actuator that achieves safety by keeping the pressure of an internal protective gas above the surrounding explosive ambient pressure.

5、浇封型电动执行器“m”

5.Pouring Type Electric Actuators "m"

整台设备或其中部分浇封在浇封剂中，在正常运行和认可的过载或认可的故障下均不能点燃周围的爆炸性混合物的电动执行器。

The whole equipment or part of it is put in a pouring agent and cannot ignite the electric actuators of the surrounding explosive mixture under normal operation and in case of an approved overload or failure of approval.