Dusts, processed in the industry, become more and more fine. In case of flammable dusts, together with air an ignitable mixture develops. With an ignition source, as sparks or hot surfaces for example, there will be an explosion.
For the preventing of the expansion of blast waves and/or sparks or flames rotary valves in pressure shock resistant and flame propagation proof design are an approved solution, especially as they complete conveying- and dosing tasks. They are installed in front of pneumatic conveying, in front of and behind mills and hoppers as well as for the safety-related separation of single installation sections.
solids – rotary valve Type SRVP was developed by S.S.T.-Schüttguttechnik for the use under Ex-requirements, pressure shock resistant and flame propagation proof.
The dimensioning and design of the rotor, especially of the gap between rotor and housing has been constructed that way that the sparks, which approach with high velocity in case of dust explosion, are extinguished inside of the rotary valves.
The axial fixing of the rotor has been adapted to the increased loads and reinforced.
The outwards shaft seal as well has been optimized by special radial sealings. This rotary valve has been tested extensively under explosion conditions by a well known and accredited testing center, the DEKRA – Exam, with mining test track. It have been conducted several test runs with dust explosions.
The prototype test has certified pressure shock resistance up to 13 bar g and flame propagation reliability. Therefore this rotary valve is a protection system category 1 acc. ATEX RL 94/9/EC and can be applied with declaration of conformity in zone 20. Due to this the operator has a maximum of plant safety.