ReAct 4 detector

ReAct 4 detector
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ReAct 4 detector for Ex zones

ReAct 4 detector

The ReAct 4 gas sensor has been developed to measure concentration of reactive gases when an Ex device is required, including aggressive and corrosive atmospheres. Designed in accordance with the ATEX Directive, it is intended to operate within explosive atmospheres (Zone 2), which also allows it to function in other harsh environmental conditions, such as when there are high temperatures, vapours, moisture or dust around.

Unique features

3 possible configurations: Without display, with local LCD or FLED display 

New innovative
measuring head 

 The sensor is designed for the detection of reactive gases (e.g. Cl2, HCl, NOx)

The ReAct 4 detector is based on a newly designed electronic platform with Bluetooth communication. The device has been developed to replace the Sigma ReAct and ReAct sensors previously offered by the manufacturer. The state-of-the-art HR measuring head the ReAct 4 detector is equipped with provides significantly better measuring properties compared to the sensors it replaces. In addition, the device has self-diagnostic features – if a malfunction is detected, it informs the user. The sensor is available in two variants – in a PES housing without display or in an acid-resistant steel housing with a unique four-colour FLED display.

Extremely simple danger indication

The ReAct 4 is also equipped with the innovative R-G-OFF (GAS-OK) system. It is a safety system that allows the efficiency of the system and the level of safety to be assessed at any time. The R-G-OFF system has been designed on the basis of easy-to-recognise light signals. The guiding principle is that any light message other than the green light obliges staff to respond immediately. This system is applicable to the ReAct 4 detector via the FLED – a four-colour optical alarm integrated into the gas sensor which enables the immediate location of a potential hazard, or via an additional LTT optical/acoustic alarm. In addition, it provides comfort and a sense of security for staff by being able to assess the emergency at any time.

Why choose the ReAct 4 detector?

  • Due to the materials used in the construction of the sensor, it is designed for the detection of reactive gases
    (e.g. Cl2, HCl, NOx).
  • Variety of gases and vapours detected.
  • Wide range of operating temperatures.
  • Housing options: aluminium, Creodur-coated aluminium, acid-resistant steel or glass-fibre-reinforced polyester.
  • Configurable current source (source/sink)
  • Dedicated accessories for the sensor.
  • Non-invasive calibration and configuration – the sensor can be calibrated and parameterised (e.g. alarm threshold values) in Ex zones without opening the housing or disabling other parts of the Gas Safety System.
  • Remote communication with the sensor.
  • Electronic compensation for ambient temperature effects.
  • Self-diagnostic function.
  • Storage in the sensor’s memory of parameters such as CAS number of the substance, location name, serial number, time between mandatory calibrations.

 Designation on the device nameplate

  1. Explosion-proof feature of the device
  2. Temperature class

Additional information related to the explosion protection of the device

  • The recommended operating position of the sensor is head down. Other items may significantly reduce the IP of the device
  • Each time the sensor housing cover is screwed on, pay attention to the housing thread.
  • Incorrect screwing may damage the threads of the housing.
  • Incorrectly tightening the screw securing the sensor housing cover can damage the housing threads.
  • Incorrectly tightening the screw securing the sensor cover can damage the threads.
  • Do not repair the flameproof joints of the device
ReAct 4 detector
Detector ReAct 4
Types of gases
Reactive gases, Diversity of detected gases and vapors. Catalytic sensors
Measurement range
LFL 0–100%
Relative humidity 10 – 90% continuously
0 – 99% momentarily
Without condensation
Pressure range 1013 ± 10% hPa
Physical features
Wiring 0,5 – 2,5 mm2
Protection degree IP 63
Weight 3,5 kg
Enclosure material Fiberglass-reinforced polyester (only for D=0)
Stainless steel
Head material Stainless steel + PTFE
-40 ≤ Ta ≤ 50°C
Electrical protection classIII
* Depending on the gas. Detailed information available in the device user manual.

Gas detection – offer

SmArtGas 4

The SmArtGas 4 gas sensor has been developed to provide reliable gas measurement, monitoring and detection in harsh environments. Designed in accordance with the ATEX Directive, it is intended to operate within explosive atmospheres

ProGas 4

The ProGas 4 sensor is a device that, despite its industrial nature, cannot be used in hazardous areas. This has its advantages, as it allows it to use the widest possible range of sensors to detect, for example, sulphur hexafluoride used in the energy industry and RX gases.

ReAct 4

Safety plates are intended for sanitary and aseptic applications, therefore, they are a perfect solution for pharmaceutical, biotechnological and food industries. Moreover, due to their properties, they can be successfully applied for gases, vapours and liquids.

RapidGas E
aspiration detector

The RapidGas E aspiration sensor is used for measurement in places that are difficult to access, dangerous to humans, or when the gas being measured has a high temperature, humidity. It is intended for use within explosive atmospheres.

LTT2 and LTT4 optical/sound
signalling device

The LTT2 or LTT4 optical/sound signalling devices provide comfort and a sense of security for workers in spaces within which SmArtGas 4, ProGas 4 or ReAct 4 detectors are used. Due to their ATEX certification, they can be used in hazardous areas.

Secure your industrial plant

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