Ex PCs / Workstations

Ex measuring- and control devices

Pressurized enclosure systems (Ex p)

F830 F840 F850-SYST F850S F850U F860S F870S OEM SR852 SR853
Ex protection class "pressurized enclosures"

Ex p- control unit FS870S

the new reference in pressurized systems

The FS870S is the revolutionary control device for pressurized enclosure systems (Ex px- systems) for uses within the Ex- Zones 1 and 21.

Compact design

The pressurized enclosure system F870S consists of the control unit FS870S and a solenoid valve at least.

Additional Ex i- user interfaces, Ex i- accessories and Ethernet interface are optional components to scale up the power of this Ex p- system.

New technology

Based on the development and introduction of the proportional valve technology for pressurized enclosure systems (Gönnheimer, patented system F850), the FS870S contains an additional, active, proportional outlet valve.

This technique allows incredible properties :

Simultaneous PID- control of cabinet pressure and flow rate

This system design allows a simultaneous PID- control of cabinet pressure and flow rate and opens new possibilities within the construction of pressurized enclosure systems and applications.

In operation mode "continuous flow" the FS870S is capable to lower the flow rate from a high value during purging to a low value during normal operation at a constant, low cabinet pressure level. (Example: 3 liters/sec. to 0.1 liters/sec. decrease without pressure variation)

Figure 1: PID control structures in FS870S

The use of the F870S system leads to a considerable stress relief of the Ex p cabinet and sensitive parts like foil keyboards, windows etc.. In comparison to conventional Ex p- systems, the FS870S requires a much lower cabinet pressure to achieve a comparable flow rate.

(Example: A reduction of the cabinet pressure by 5 mbar leads to 50 kg / m² decreased load at the cabinet walls).

Outstanding pneumatical properties

Enlarged, free programmable range of operation

In comparison to common Ex p control systems, the FS870S offers an increased and free programmable range of operation (characteristic pressure / flow curve).

The conventional systems are characterized by a fixed pressure / flow curve (see e.g. FS850S figure 2) with an offset, caused by the opening pressure of the passive mechanical outlet valve. This typical opening pressure (2.. 4 mbar at standard systems) is required to minimize the system leakage rate during normal operation.

Figure 2: fixed characteristic curves by conventional control devices
The input and output sided PID-control loops allow the FS870S to perform in the whole range of operation (see figure 3).

Figure 3: range of operation FS870S

Lowered cabinet stressing due to smaller absolute pressure and pressure gradients

During the purging phase a high flow rate should be achieved to shorten the purge time. Based on their construction, conventional Ex p- systems show only a smooth rising of the flow rate while increasing the cabinet pres-sure.

In this aspect, the FS870S with its reduced flow restriction and back pressure is superior to any conventional Ex p system.

Within midrange flow rates, the load to the Ex p- cabinet walls is up to four times lower in comparison to conventional systems!

Reduced purge pressure

At conventional Ex p- control systems, the purge pressure has to be set several times higher than the pressure during normal operation, to achieve an adequate and quick purging phase.

Using the FS870S, the pressure level during purging and normal operation phase can stay constant. Thereby, the flow rate is increased in comparison to comparable, conventional purge systems.

Figure 4: pressure levels

If required, the operator can program a higher purge pressure level, e.g. to reach a further shortening of the purging time.

Innovative interfaces

Ex i- bus interface

The intrinsically safe bus interface is used to transmit measurement values from the external proportional sensor module ES872 to the control unit. This allows the integration of additional safety control features into the purge control system.

Using the same Ex i- bus, the customer can connect the optional configuration module CM873 to load application specific configuration data and parameters into the control unit without further manual programming.

Ethernet interface

Use the supervisory control system / SCADA system or the web browser of your PC to check the system status, the system configuration and the log file of the FS870S.

The Ethernet interface and the integrated web server support a wide ranging information interchange to the SCADA system across the application layers.

Figure 5: PDA shows web interface of the F870S

  last modified: 24.11.2010