Explosion protection for conveyors
The diversity of conveyors does not allow for a standard protection plan. Various measures may be used to prevent explosions without installing protective equipment such as:
- limiting conveying speeds,
- using suitable material pairings
- using safety-relevant designs
The risk of combustion may be reduced by the conveyors themselves.
Open, non-encased belt conveyors are considered the least critical, since the conveyed material usually does not become airborne and does not have any direct contact with hot surfaces.
On the other hand, enclosed conveyors will have will have different explosion risk levels which depend on the facility zoning and ignition danger evaluation. Factors affecting the risk levels include: the fineness of dust, moisture content and dust formation probability of the material, the conveying principle and the conveying speed of the system parts. At a minimum, isolation from connected equipment is required, using quench valves, check valves or chemical barriers
Screw conveyors may be handled differently since they can be converted into their own isolation device with the help of expert guidance. For this purpose, a certain flight may be removed from the auger. This new empty space automatically fills during normal operation. In the event of an explosion, the conveyed product will fill the entire cross-sectional area and form a plug. This plug will then function as an isolation device since it prevents propagation of the explosion into connected facility equipment. The feasibility of this measure heavily depends on the flow of the material and the installation length of the auger.
Trough conveyors: Here, the open top section prevents the ability for the product to fully fill the entire cross-section. This usually leads to the need for explosion protection equipment such as explosion vents or chemical barriers. A cost effective, maintenance-free explosion vent, installed on top of the trough screw conveyer, will open when explosion pressure reaches a predefined level, allowing for a safe release of the explosion. Alternatively, chemical barriers are controlled by pressure or infrared detectors which detect a resulting explosion and trigger the extinguishing agent. The extinguishing agent, which is then discharged, will cool and stop the explosion from fully developing.
Does your production facility have the following conveyors and need expert consulting regarding Explosion Protection?
- Trough chain conveyor
- Screw conveyors
- Conveyor belt
- Belt conveyor
- Tube chain conveyor
Call us, we will gladly assist you.
The overall picture counts:
The protection of individual system components is only as good as the protection of the entire system. To insure you have a safe and economical Explosion Protection plan, your total system must be examined and protected.
Pay particular attention that there are sufficient isolation devices. Also, guard against “over engineering”.
We offer you comprehensive protection plans and on-site consulting, so you can implement organizational measures to achieve a greater degree of safety.