Innovative Ex p system with three basic components

With the Ex p x621 con­trol and mon­i­tor­ing sys­tem, the explo­sion pro­tec­tion com­pa­ny R. STAHL presents a new type of mod­u­lar solu­tion for sim­pli­fied assem­bly of pres­sur­ized enclo­sures with Ex p type of pro­tec­tion. While con­ven­tion­al sys­tems use a high vari­ance of ded­i­cat­ed devices for dif­fer­ent enclo­sure sizes and designs, the com­pa­ny reduces the com­plex­i­ty with its new sys­tem solu­tion to three basic com­po­nents in a uni­form design: The com­bi­na­tion of Ex p con­trol unit, Ex p pres­sure switch­es, which also serve as pres­sure out­lets, and Ex p purge valves with dig­i­tal and pro­por­tion­al con­trol cov­ers all require­ments from very small enclo­sures with 10 l vol­umes up to Ex p enclo­sures with vol­umes of 4000 l. The con­trol unit pro­vides the con­trol sequences for the Ex p con­trol system.

The con­trol unit pro­vides con­trol sequences for all enclo­sure sizes and allows them to be eas­i­ly adapt­ed as required. If, for exam­ple, a reduc­tion in purg­ing pres­sure or purg­ing times is required for larg­er con­trol cab­i­nets, only addi­tion­al Ex p pres­sure switch­es need to be installed. The use of only one type of pres­sure switch in quan­ti­ties to meet require­ments reduces both engi­neer­ing and ware­hous­ing costs. At the same time, the high pre­ci­sion of the pres­sure sen­sors used enables oper­a­tion close to the pres­sure shut-off thresh­old, which keeps leak­age quan­ti­ties to a min­i­mum and per­mits extreme­ly cost-effec­tive con­tin­u­ous operation.

Sim­pli­fi­ca­tion is also pro­vid­ed by the purge valve con­trol, also inte­grat­ed in the con­trol unit, in either dig­i­tal or pro­por­tion­al mode. Effec­tive Ex p vor­tex air cool­ers are also avail­able for cool­ing cab­i­nets. Their cool­ing capac­i­ty can be scaled — accord­ing to the same sim­ple prin­ci­ple as for the pres­sure switch­es — by installing fur­ther iden­ti­cal ver­sions. The Ex p bypass cir­cuit of the con­trol unit, in which the elec­tron­ics oper­ate in intrin­si­cal­ly safe mode, con­sid­er­ably reduces the effort required for inspec­tion and main­te­nance work. The nov­el com­mis­sion­ing process elim­i­nates cost­ly test steps after main­te­nance and retro­fit inter­ven­tions and ensures Ex pro­tec­tion at all times.

The cer­ti­fied mon­i­tor­ing sys­tem for con­trol cab­i­nets is used in Ex zone 1/21 accord­ing to IEC/EN/DIN 60079–2 as a redun­dant ver­sion and in Ex zone 2/22 as a cost-reduced sin­gle ver­sion. The com­pact design of the com­po­nents and the mod­ern user inter­face of the Ex‑p con­trol unit enable space-sav­ing instal­la­tion and sim­ple com­mis­sion­ing. Due to the exter­nal mount­ing of the con­trol unit on the con­trol cab­i­net side wall, the full instal­la­tion vol­ume is reserved for the appli­ca­tion. The hous­ing made of resis­tant glass-fiber rein­forced poly­ester is avail­able with or with­out view­ing window.