Propagating brush discharges in flexible hoses

Propagating brush discharges can occur inside conductive pipework with an insulating liner when pneumatically conveying powders. Flexible plastic hoses with embedded wire spirals are frequently used for pneumatic transfer, but it has not been clear if they have the same problem. This work shows that propagating brush discharges can occur in structures modelling such hoses. Further work is required to establish if mitigating factors are present in actual hoses. Nevertheless, the advice from this work must be that such hoses should not be used for pneumatic transfer of flammable powders unless the plastic is static dissipative or conductive.