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

電動執行器被使用在十分惡劣的、往往有很多易燃易爆氣體混合物的工作環境中，因此對電動執行器的防爆功能有著很高的要求，這樣才能保證電動執行器使用的安全性和有效性。本文以中英合資天蝶閥門生產的防爆型電動執行器為例，分析如何進行智能型電動執行器的防爆結構設計。

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、隔爆型電動執行器“d”

1. Flameproof electric actuator " d "

一種具有隔爆外殼的電動執行器。隔爆外殼能承受已進入外殼內部的可燃性混合物內部爆炸而不損
壞，并且通過外殼上的任何接合面或結構孔不會引燃一種或多種氣體或蒸氣所形成的外部爆炸性
環境的電動執行器外殼。

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、增安型電動執行器“e”

2.Increased safety electric actuator "e"

一種對在正常運行條件下不會產生電弧、火花的電動執行器采取一些附加措施以提高其安全程度，防止其內部盒外部部件可能出現危險溫度、電弧或火花的電動執行器。

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、本質安全型電動執行器“i”

3.Intrinsically Safe Type Electric Actuators "i"

本質安全通常指某個系統，而不是指某一個設備。人們通常說一個變送器或傳感器或傳感器是本質
安全時，這是一種簡化說法，實際上本質安全指變送器或傳感器經電纜與關聯設備（安全柵等）組成的本質安全系統。

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.).

本質安全電路

Intrinsically safe circuit

本質安全電路指在規定條件（包括正常工作和規定的條件）下產生的任何火花或任何熱效應均不能點燃規定的爆炸性氣體環境的電路。

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.

本質安全設備

Intrinsic safety equipment

本質安全設備指在其內部的所有電路都是本質安全電路的電動執行器。

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

關聯設備

Associated equipment

關聯設備指內部裝有本質安全電路和非本質安全電路，且結構使非本質安全電路不能對本質安全電路產生不利影響的電動執行器。關聯設備在危險場所安裝使用時， 應加其他形式防爆外殼保護，例如隔爆型、正壓型等；在安全場所安裝使用時，其外殼可選用一般型。在本質安全系統中與本質安全設備有電氣連接，接口部分有限壓， 限流環節（限制能量）的電動執行器可認為是關聯電動執行器，如齊納安全柵、隔離式安全柵、本質安全電源、光電隔離接口電器等。

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、正壓型電動執行器“p”

4.Positive Pressure Type Electric Actuators "p"

一種通過保持內部保護氣體的壓力高于周圍爆炸性環境壓力的措施來達到安全的電動執行器。

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

5、澆封型電動執行器“m”

5.Pouring Type Electric Actuators "m"

整臺設備或其中部分澆封在澆封劑中，在正常運行和認可的過載或認可的故障下均不能點燃周圍的爆炸性混合物的電動執行器。

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.