Air jacket and spark trap
Air at pressure above atmospheric can prevent ignition hazards for electrical equipment operated in potentially explosive atmosphere
Dangerous neighbourhood: electrical equipment in a room or area in which flammable gases may occur. There is only one thing one can do: The ignition source (spark or hot components) must be separated from the gas source - by an air buffer, for example. In the case of the pressurization type of protection, this is achieved in a simple way: The equipment is rinsed with air and pressurized so that no explosive ambient air can penetrate. The so-called gauge pressure must be constantly controlled. It is the PTB's task to check whether this mechanism functions properly.
PTB thus renders a service to the manufacturers who, under European regulations, are bound to prove that the severe explosion protection regulations are observed by them. And yet another service: The PTB certifies that the manufacturers have taken explosion protection into account in production and in their quality management systems. In both cases a certificate is issued to the manufacturers.
Whoever wants to obtain more detailed information about the PTB's test work can contact its experts at the ACHEMA in Frankfurt/Main between May 21 and 27, 2000 (Hall 9.1, Stand K21/22, telephone at the fair: ++49 (0)69 7 44 12 55).
Additional information can be obtained from:
Dr. U. Johannsmeyer, tel. ++49 (0)531-592-3420; e-mail:ulrich.johannsmeyer(at)ptb.de
W. Ellwardt, tel. ++49 (0)592-3523; e-mail: wolfgang.ellwardt(at)ptb.de
Intrinsic Safety and Safety of Systems section,
Physikalisch-Technische Bundesanstalt (PTB)