Atex devices and installations
Devices and installations accordant with the ATEX, intended to extract dusts from dust & air explosive mixtures
In many sectors of industry it is frequently required to de-dust air & dust mixtures which are very explosive. Mainly, it concerns processes related with processing of coal, biomass, wood in wood industry, organic dusts in a foodstuffs industry, dusts in chemicals industry etc.
To de-dust air & dust explosive mixtures we offer devices and complex installations performed acc. to binding ATEX Directive (2014/34/UE). They can be used to extract dusts belonging to St1 and St2 explosiveness class. Our filtration systems belong to 3 D category. It means they can be erected in any location classified as a non-explosive zone and in 22 zones, which are explosive.
MECHANISMS OF ACTION AND STRUCTURE
In order to protect the units we propose two basic methods:
- Explosion damping method
This method applies systems, which react automatically to start of an explosive pressure and they damp a potential explosion. The system comprises sensors of the pressure which detect occurring explosion, transfer information to a central unit which, in turn, starts valves applying an extinguishing agent. System’s reaction time from detection of an explosion till it has been extinguished is 60 ms only. Quick damping of occurring explosion prevents from high damaging pressure.
- Explosion discharge method
It applies all types of membranes or de-compression panels which transfer pressure of explosion from protected device into outside. In this way the pressure in a protected device will be reduced up to value which does not constitute a hazard. We apply varied types of membranes: round, rectangular or convex, with sensors or without them, made from coal steel or acid-proof steel. Because of flame length of explosion transferred into outside it required to set out a hazard zone in a space near a membrane.
Additionally, on the grounds of explosion hazard zones within a particular installation, all of its parts and sub-assemblies will be adjusted in such a way that they are not a reason for dust ignition source.
The systems in question can be fastened on devices without a need to set out a hazard zone.
Methods of installation protection (isolation of explosion)
In order to prevent move of explosion into open channels connected to a protected device, we offer systems and devices intended to isolate an explosion. At the side of inlet and outlet channels there are applied mechanical devices or automatic HRD barrier: Mechanical devices:
- Return hatches
They close when affected by a pressure wave which goes before a flame wave in a protected channel. During normal operation the hatch is opened by means of flowing gas stream.
- Quick gate valves
After detection of an explosion the gate valves are quickly closed
- Divertors (anti-explosion chimneys)
A divertor comprises two channels in form of reversed V letter and a safety plate in the upper part of the device. An impact wave, which occurs during an explosion, because of its inertia and large speed does not change direction and it is ejected outside as a result of safety plate damage.
- Quick shutting-off valves
The devices in question are recommended only in de-dusting systems intended for small dust concentration. Higher dust concentration can prevent return hatch from total closure. Automatic HRD barrier During an explosion in the channel there moves a pressure and it is followed by a flame. Both values can be detected by optical and pressure sensors. Central control unit, after it has received information from sensors, gives an impulse to open HRD cylinder valves. At this moment, into entire volume of the channel there is supplied an extinguishing agent which is a barrier for the flame. An advantage of this system is possibility to apply it in installations characterized by large dust concentration.
Protection methods - dust collection side
Discharge of dusts is protected mainly by means of rotary valves with ATEX certificates. Their structures disable transfer of explosion outside the device.
- In our installations we apply proven devices and systems
- All devices have required certificates issued by an authorized notified body in the area of the European Union.
- Our experts assure optimal selection of de-dusting devices as well as devices and protective systems for a particular application.