防爆型和本安型压力开关指南（中英文）

压力开关在保障工业过程安全稳定运行方面发挥着至关重要的作用，尤其是在可能存在易燃气体、蒸汽或粉尘的危险区域。选择合适的保护方案对于确保合规性、降低风险和维持可靠运行至关重要。

本指南阐述了防爆型 (Ex d) 和本质安全型 (Ex ia) 压力开关之间的区别、每种保护方式的工作原理，以及在为安全关键型环境选择产品时需要考虑的关键因素。

Pressure switches play a vital role in keeping industrial processes safe and stable, especially in hazardous areas where flammable gases, vapours or dust may be present. Choosing the right protection concept is essential to ensure compliance, reduce risk and maintain reliable operation.

This guide explains the differences between explosion proof (Ex d) and intrinsically safe (Ex ia) pressure switches, how each protection method works, and the key factors to consider when selecting a product for safety critical environments.

什么是压力开关？

What Are Pressure Switches?

压力开关是一种机电装置，用于监测过程压力，并在压力达到设定值时激活电触点。它们广泛应用于以下行业：

• 石油和天然气生产

• 化学和石化加工

• 发电

• 水处理和废水处理

• 海洋和近海环境

• 制药

• 食品和饮料等制造业

• 空调暖通 (HVAC)

• 消防

典型应用包括泵和压缩机控制、报警、过滤器监测以及液压、气动或过程系统的保护。

在分区危险区域，压力开关必须经过特殊设计，以防止周围潜在爆炸性气体的点燃，而这正是认证保护发挥作用的地方。

A pressure switch is an electromechanical device designed to monitor process pressure and activate an electrical contact when the pressure reaches a defined setpoint. They are widely used in industries such as:

• Oil and gas production
• Chemical and petrochemical processing
• Power generation
• Water and wastewater
• Marine and offshore environments
• Pharmaceutical manufacturing
• Manufacturing, such as food and drink
• HVAC
• Fire protection

Typical applications include pump and compressor control, alarms, filter monitoring, and protection of hydraulic, pneumatic or process systems.

In Zoned hazardous areas, pressure switches must be engineered to prevent ignition of the surrounding potentially explosive atmosphere, and that’s where certified protection comes in.

防爆型压力开关与本质安全型压力开关

Explosion Proof vs. Intrinsically Safe Pressure Switches

防爆（阻燃）压力开关

Explosion Proof (Flameproof) Pressure Switches

防爆型（也称阻燃型，Ex d）是一种防护方法，其压力开关采用坚固的外壳，能够承受内部爆炸。即使可燃气体进入设备内部并被点燃，火焰导流路径和重型外壳也能阻止爆炸蔓延到外部环境。

主要特性：

• 厚壁重型外壳

• 火焰导流路径设计用于冷却逸出气体

• 适用于 1 区和 21 区

• 适用于大功率开关应用

• 无需外部屏障

防爆压力开关常用于海上平台、炼油厂、压缩机撬装设备以及其他对坚固性和高电气负载要求极高的场所。

Explosion proof, also known as flameproof (Ex d), is a protection method in which the pressure switch is built with a robust enclosure capable of withstanding an internal explosion. Even if flammable gases were to get inside the device and be ignited, the flame paths and heavy duty housing prevent the explosion from propagating to the external environment.

Key Characteristics:

• Thick-walled, heavy duty enclosure
• Flame paths designed to cool escaping gases
• Suitable for Zones 1 and21
• Ideal for high power switching
• No need for external barriers

Explosion proof pressure switches are commonly selected for offshore platforms, refineries, compressor skids and other installations where ruggedness and high electrical loads are critical.

本安型压力开关

Intrinsically Safe Pressure Switches

本质安全型 (Ex ia) 压力开关限制电路中的可用能量，即使在故障情况下也不会发生点火。本质安全型开关并非仅仅抑制爆炸，而是从源头上防止爆炸发生。

与齐纳二极管或电隔离器配合使用的 Ex ia 压力开关，可确保控制回路中的电能始终低于点火阈值。

主要特性：

• 节能电路

• 轻巧紧凑的结构

• 适用于低功率信号传输

• 简化安装和维护

• 适用于 0、1、2、20、21 和 22 区

它们适用于仪表回路、远程遥测、储罐区、化学加药系统以及需要非侵入式维护的环境。

Intrinsically safe (Ex ia) pressure switches limit the energy available within the circuit so ignition is not possible, even under fault conditions. Rather than containing an explosion, intrinsic safety prevents one from occurring.

Ex ia pressure switches used with a Zener barrier or galvanic isolator, ensure the electrical energy in the control loop stays below ignition thresholds.

Key Characteristics:

• Energy limited circuits
• Light, compact construction
• Ideal for low power signalling
• Simplifies installation and maintenance
• Suitable for Zones 0, 1, 2, 20, 21 and 22

They’re preferred for instrumentation loops, remote telemetry, tank farms, chemical dosing systems, and environments where access must be noninvasive for maintenance.

如何为危险区域选择合适的压力开关

How to Choose the Right Pressure Switch for Hazardous Areas

选择合适的防护方式取决于工艺流程和风险环境。关键因素包括：

1. 危险区域分类

• 本质安全型或 Ex ia 型压力开关通常用于 0 区和 20 区。

• 防爆型或 Ex d 型压力开关广泛应用于 1 区和 21 区，以应对更高的电气负载。

2. 电气要求

防爆型压力开关适用于直接切换，而本质安全型压力开关则设计用于低能耗仪表。

3. 机械强度

在可能发生振动、冲击或机械损坏的情况下，采用防爆外壳可能更具优势。

4. 工艺条件

考虑工艺介质和压力范围：

• 气体、液体或液压油

• 稳定压力或脉动压力

• 所需的设定点稳定性

• 接触介质部件的兼容性

5. 维护与检修

本质安全型设备简化了现场维护，因为在许多情况下，无需气体释放或动火作业许可证即可进行带电作业。

Selecting the right protection method depends on both the process and the risk environment. Key factors include:

1. Hazardous Area Classification

• Intrinsically safe or Ex ia is often required for Zones 0 and 20.
• Explosion proof or Ex d is widely used in Zones 1 and 21 for higher electrical loads.

2. Electrical Requirements

Explosion proof switches are suitable for direct switching, while intrinsically safe models are designed for low energy instrumentation.

3. Mechanical Robustness

Where vibration, shock or mechanical damage are possible, a flameproof housing may be advantageous.

4. Process Conditions

Consider the process media and pressure range:
• Gas, liquid or hydraulic oil
• Steady or pulsating pressure
• Setpoint stability needed
• Compatibility of wetted parts

5. Maintenance & Access

Intrinsically safe devices simplify maintenance in the field because liveworking is permitted without gasfreeing or hotwork permits in many cases.

ATEX压力开关的应用实例

Application Examples of ATEX Pressure Switches

ATEX和IECEx认证的压力开关广泛应用于各种危险和恶劣环境中，以保护设备和人员，并有助于维持安全高效的运行状态。以下是防爆压力开关的应用实例：

• 油气作业井口控制

• 氢气暖通空调压缩机和冷水机组

• 安全淋浴和洗眼系统

ATEX and IECEx certified pressure switches are used across a wide range of hazardous and harsh environments to protect equipment, personnel and help maintain safe and efficient operating conditions. See below examples where explosion proof pressure switches have been deployed:

• Wellhead Control for Oil and Gas Operations
• HVAC Compressors and Chillers for Hydrogen
• Safety Showers and Eyewash Systems

压力开关保护概念概览

Pressure Switch Protection Concepts at a Glance