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Ex-DDCM Differential Pressure Switches for Liquids and Gases

FEMA Ex-DDCM differential pressure switches are used for monitoring and controlling differential pressures in potentially explosive atmospheres. They are suitable for applications with liquids and gases where pressure differences between two measuring points must be detected reliably and transmitted as an electrical switching signal.

The Ex-DDCM series is particularly suitable for differential pressure monitoring, flow monitoring and automatic control of filter systems. A dual-chamber system with a stainless steel bellows or Perbunan diaphragm detects the difference between the high-pressure and low-pressure connections. The required switching pressure can be continuously adjusted within the respective setting range.

The devices are designed as Ex versions for potentially explosive atmospheres. The product information specifies, among others, the explosion protection markings Ex II 2G Ex d e IIC T6 Gb and Ex II 1/2D Ex ta/tb IIIC T80 °C Da/Db. SIL2 according to IEC 61508-2, ATEX 2014/34/EU and IECEx are also specified. This makes Ex-DDCM suitable for demanding industrial applications requiring differential pressure monitoring and explosion protection.

All Ex-DDCM differential pressure monitors can also be used in the negative pressure range, provided that the respective application and device version are suitable. The switching differential is not adjustable and is defined by the respective device version. The robust housing is made of seawater-resistant die-cast aluminium GD Al Si 12.

The device can be mounted directly on the pressure line or on a flat surface using two screws. When connecting the pressure lines, the connection assignment must be observed: P (+) stands for the higher pressure, S (-) for the lower pressure.

Typical Applications

• Differential pressure monitoring in potentially explosive atmospheres
• Pressure monitoring and differential pressure control for liquids and gases
• Flow monitoring via differential pressure
• Automatic filter monitoring and filter control
• Monitoring of steam, gas, hot water and cold water
• Pump monitoring and control of pressure losses
• Limit monitoring in process plants, pipelines and assemblies

Advantages of FEMA Ex-DDCM Differential Pressure Switches

• For hazardous areas: designed for potentially explosive system areas
• For liquids and gases: versatile use in industrial media circuits
• Differential pressure and flow: suitable for monitoring pressure differences and flow
• Ideal for filter systems: automatic monitoring of filter contamination and pressure loss possible
• Continuously adjustable switching pressure: adjustable within the respective setting range
• Robust housing: seawater-resistant die-cast aluminium GD Al Si 12
• Certified design: depending on the version, with ATEX, IECEx and SIL2 according to IEC 61508-2

Ex-DDCM Differential Pressure Switches at ICS Schneider

ICS Schneider offers FEMA Ex-DDCM differential pressure switches for demanding applications with liquids and gases in potentially explosive atmospheres. The devices are suitable for operators, plant manufacturers and service companies that require a robust mechanical solution for differential pressure monitoring, flow monitoring or filter monitoring.

When selecting the correct Ex-DDCM switch, the medium, differential pressure range, required switching point, maximum permissible pressure, temperature, connection type, measuring element material, Ex zone, explosion protection type, electrical switching capacity, protection rating, installation situation and required monitoring function should be considered. For Ex applications, the design should always be based on the specific system classification and applicable explosion protection requirements.

FAQ – Frequently Asked Questions about FEMA Ex-DDCM Differential Pressure Switches

1. What is a FEMA Ex-DDCM differential pressure switch?

A FEMA Ex-DDCM differential pressure switch is a mechanical switching device used to monitor pressure differences between two measuring points in potentially explosive atmospheres. When the set differential pressure is reached, the device actuates an electrical switching contact.

2. Which media is Ex-DDCM suitable for?

Ex-DDCM is suitable for applications with liquids and gases. Exact media compatibility depends on the device version, measuring element, pressure range, temperature and operating conditions.

3. What is Ex-DDCM typically used for?

Typical applications include differential pressure monitoring, flow monitoring, filter monitoring, pump monitoring, pressure loss control and pressure monitoring in process plants with Ex requirements.

4. How does Ex-DDCM detect differential pressure?

The pressure difference is detected via a dual-chamber system. Depending on the version, a stainless steel bellows or Perbunan diaphragm is used. This measuring element actuates a microswitch when the switching point is reached.

5. Is the switching pressure adjustable?

Yes. The required switching pressure can be continuously adjusted within the respective setting range. This allows the differential pressure switch to be adapted to the application.

6. Is the switching differential adjustable?

No. The switching differential of Ex-DDCM differential pressure switches is not adjustable. It is fixed depending on the respective device type and pressure range.

7. Can Ex-DDCM switches be used in the negative pressure range?

Yes. Ex-DDCM differential pressure monitors can also be used in the negative pressure range, provided that the respective device version and application are suitable.

8. Which connections are intended for high and low pressure?

Connection P (+) is intended for the higher pressure. Connection S (-) is intended for the lower pressure. This assignment is important for correct differential pressure measurement.

9. Is Ex-DDCM suitable for filter monitoring?

Yes. Filter monitoring is a typical application. As filter contamination increases, the pressure loss rises. The Ex-DDCM detects this difference and can provide a switching signal for maintenance, alarm or control.

10. Which Ex marking is specified for Ex-DDCM?

The product information specifies, among others, Ex II 2G Ex d e IIC T6 Gb and Ex II 1/2D Ex ta/tb IIIC T80 °C Da/Db. Exact suitability must match the Ex zone and system classification.

11. Which certificates are specified?

For Ex-DDCM, SIL2 according to IEC 61508-2, IBExU12ATEX1040 according to ATEX 2014/34/EU and IECEx IBE 14.0077 are specified, among others.

12. What information is important for selecting the correct version?

Important information includes the medium, differential pressure range, required switching point, maximum pressure, temperature, process connections, measuring element, electrical switching capacity, Ex zone, explosion protection type, protection rating, mounting type and required monitoring function.