Siemens - Model MAXUM ed. II - EPC4 -Electronic Pressure Controller

Continuing enhancement for the Maxum GC platform – new EPC4

High accuracy for optimized operation

Changes in ambient temperature and pressure impact the performance of a gas chromatograph’s pressure control system during an analysis. To minimize the impact in changing temperature conditions, the new electronic pressure controller is calibrated over the entire temperature range of the Maxum GC of -20 to 50°C. Additionally, an integrated ambient pressure sensor automatically compensates for any changes to ambient pressure or connecting to a regulated exhaust system. This results in the EPC4 providing the highly stable carrier pressure control that process gas chromatographs need even at low flow and low-pressure ranges.

Integrated pressure switches for ease of use
Maintaining the gas chromatography operation requires a constant carrier gas supply. Monitoring the supply gas pressure below a threshold indicates the available remaining amount of gas in a gas bottle and was previously indicated by an external pressure switch. The new EPC4 has an option for an integrated pressure switch at the point of use, giving the possibility to set fault and alarm levels for the predictive exchange of a carrier gas bottle before it runs low.

Simplified use with Intrinsically Safe protection methods
Intrinsic Safe (IS) circuits are designed to operate at sufficient low energy levels that short circuit and energy content are incapable of causing ignition of a hazardous atmosphere environment. By using intrinsically safe design concepts, it is possible to greatly simplify the safety architecture a device.

The new EPC4 integrates this IS protection concept which allows the EPC4 to be split into two segments - the IS Pressure Module (ISPM) that is mounted externally in the regulator section and the IS Controller Module (ISCM) mounted inside the electronics compartment. Each ISCM can operate up to four ISPM via an intrinsically safe cable with ISPM has 2 EPC channels each.

Reference pressure connection
Avoiding emissions is becoming a growing concern for plant operations; especially, for operating under minimum environmental impact conditions. As a result, vent header systems are a preferred practice to overcome unnecessary emissions for a chromatographic system like the MAXUM ed. II. However, connecting all GC vents to such a system leads to complications for the ambient pressure sensing of the EPC.

The new design of the EPC4 pressure module offers the possibility for an easy connection to the vent header system. Concerns that hazardous gases might get back to the pressure module are resolved as the 15PM is not considered an ignition source.
Backwards compatibility and Certification

The MAXUM ed. Il`s unique design enables the incorporation of leading-edge analytical technology at any time without the fear of obsolescence. Supporting the installed base and offering new technologies to existing MAXUM ed. II gas chromatography systems has always been the goal for product innovations.

With the individual certification of the controller and pressure module, the new EPC4 offers a fully backwards compatible system, which can be integrated into existing MAXUM ed. II gas chromatographs. The EPC4 ISPM form and size matches the existing EPC3 installation, making retrofits easily possible. Even combinations of EPC3 and EPC4 in the same analyzer are possible. The EPC4 will be the fully compatible spare part of any MAXUM ed. II analyzer, and that way support the installed customer base with the latest available technology.