Purge/Pressurization Challenges Reduced at the Outset

June 12, 2008
Pepperl+Fuchs’ 6000-series Type X/EEx Purge/Pressurization System Offers Versatility to Customers

Customers no longer have to provide configuration information when ordering, since the new AC- or DC-powered unit has a user-friendly programming screen. Moreover, it provides environmental and safety peace-of-mind, being enclosed in stainless steel and rated for hazardous gas and dust atmospheres. Kit versions allow for custom, cost-effective modular solutions for enclosures up to 250 ft3 (7.1 m3).

The 6000-series Type X/EEx px system is an addition to the Bebco EPS line. Within the robust, Type 4 X (IP66) housing are the controller, pneumatic, electrical I/O and programming interfaces. Its vent, besides providing feedback to the controller on pressure and flows, also acts as a pressure-relief device for all appropriate enclosure sizes. It can be mounted either horizontally or vertically on the enclosure. A proportional valve is available if continuous flow and pressure control are desired.

An LCD screen shows  pressure, flow and system status information in digital form. The user interface allows programming of up to four switch inputs, temperature modules, enclosure power contacts, two auxiliary outputs and various operational functions. Complementing its control flexibility, the 6000 series’ menu-equipped user interface simplifies programming, with diagnostics for reviewing start-up and operational parameters.

The 6000-series’ principal features include:

  • Explosion/flameproof electronic processor housing;
  • Intrinsically safe electrical/pneumatic manifold assembly, with rating for Class I and/or Class II, Division I/Zone I and/or Zone 21 operation;
  • IECEx-, cULus-, ATEX directive-certified;
  • IEC 61508, SIL 2, and SIL 3 options available;
  • I/O connections and controls for operation;
  • IS user interface for programming and monitoring;
  • Stainless steel (316L for all exposed parts) Type 4X enclosure for EPCU and connections;
  • Automated purging and pressurization;
  • Pressure relief vent.
  • The electronic processor (EPCU) comprises redundant microprocessors, enclosure power contacts, two auxiliary contacts, power supply module, galvanically isolated barriers for the inputs, vent(s) and temperature modules. All are stackable and easy to insert/remove from the housing. Power supply can be either 24 Vdc or 100 Vac to 240 Vac.
The intrinsically safe 20x20-LCD user interface on the unit’s face can be mounted remotely. Programming of configuration and all options are accomplished through a set of menu-driven buttons. Five color LEDs give easy indication of operation, distinctively showing safe pressure, enclosure power, rapid exchange, system bypass and alarm faults.

Four intrinsically safe inputs activate various EPCU actions and outputs. They accept only dry contact for activation, and are supplied by the EPCU’s galvanically isolated barrier. Inputs for various actions are assigned through the user-interface controller. Only one function can operate an input. Inputs can bypass the system for live maintenance on the enclosure. In addition to many other actions and outputs, the intrinsic safety inputs activate the auxiliary relays, energize the rapid exchange valve, de-energize the enclosure contacts, and shut the system down.

Two normally open, dry contacts for enclosure power can be energized only after a successful purge and achieving a minimum enclosure pressure.

Purging can be based on a known purge rate and a fixed time, or done dynamically with the time determined by the flow rate being measured from the vent.

There are four possible start-up modes:

  • Standard, with operator engagement of the manifold solenoid valve;
  • Semi-automatic, requiring operator’s manual engagement of the manifold solenoid valve—the EPCU will automatically disengage when purging is successfully completed;
  • Fully automatic—when safe pressure is detected, the solenoid valve will engage without operator intervention and disengage on completion of purging;
  • Proportional mode, which continuously controls the flow rate during and after purging.

The vent is universally mounted to an application enclosure of up to 450 ft3 (12.7 m3).

For more information call 330/486-0002 or email [email protected].