pControl 2F
Backpressure Controller for process gas analyzers

Features and typical applications

Corrosion resistant backpressure controller for process gas analyzers - pControl 2F

Typical Applications

  • Precise measurement at constant pressure instead of insufficient or impossible pressure correction algorithms
  • Long-term stable pressure control also for gases with high corrosion potential
  • Sample gas return into process at defined higher pressure
  • Defined setpoint pressure to dispose of flammable and toxic sample gases into a flare or scrubber

Key Features

  • Eliminate pressure errors at the source
  • Quick and precise pressure control
  • Back pressure regulator for sample conditioning systems
  • Extremely wide range of gas flow allows use with multiple gas analyzers



In the field of gas analysis an analyzer's response is often dependent upon the sample gas pressure. Pressure dependency can occur through a number of different physical parameters simultaneously and can be difficult to impossible to correct for. The best and most accurate approach is therefore to control the absolute pressure itself. The use of an LFE pControl backpressure controller alleviates the need for complicated correction algorithms.

A further benefit of an LFE pControl backpressure controller is e.g. the return of the analyzed gases back into the process (being achieved by a defined higher pressure). Alternatively the sample gas can be fed to a flare or scrubber requiring a defined higher pressure. In this way unnecessary emissions into the environment or loss of gas can be avoided. Flammable or toxic gases can be handled appropriately. The LFE pControl backpressure controller typically operates at approximately 0.2 bars above ambient pressure (i.e. 1.2 bar absolute), but can be easily set to other operating pressures.

Backpressure controller instead of pressure corrections with wide flow range for gas analyzers - pControl 2F

The specially designed control valve of the LFE backpressure controller provides for an extremely constant pressure over an extremely wide range of gas flow (e.g. from 5 ln/h up to 1000 ln/h). This allows for a single LFE pControl to be used in conjunction with a number of gas analyzers.

The piezo-resistive pressure transducer is temperature controlled to improve stability. An optional PTFE isolating diaphragm is available to improve corrosion resistance.



  • Eliminate pressure errors at the source instead of calculated corrections
  • Adjustable, quick and precise pressure control
  • Extremely wide range of gas flow: 5 up to 1000 ln/h
  • A single pControl system for use with multiple gas analyzers
  • High corrosion resistant version for aggressive gases
  • Improved stability by temperature controlled transducer
  • Sample gas return into process instead of emissions
  • Flammable and toxic gases via flare or scrubber

Technical data

Technical data

Technical specifications subject to change without notice

Enclosure & electrical data

Enclosure Purgeable cast aluminum housing for wall-mounting
Protection class IP65
Dimensions 230 x 330 x 185 mm (HxWxD)
Weight approx. 10 kg
Power supply 100 - 240 VAC / 50 - 60 Hz / 50 VA max.
Materials in contact with sample gas
Internal gas lines PTFE and PVDF
Control valve PTFE and PVDF with FPM seals
Sample gas connectors Standard: stainless steel (SS 316)
Option: PVDF (in conjunction with optional PTFE isolating membrane)
Pressure transducer Polyester, silicon and silicone compounds
Note: enhanced corrosion resistance is attained with the optional PTFE isolating membrane

Operational characteristics

Measuring range Standard: 1.0 - 1.5 bar absolute (other ranges on request)
Range of flow Dependent upon setpoint pressure and pressure at gas outlet.
Example: setpoint at 1.2 bar (abs.) and outlet at atmospheric pressure:
Range of flow: 5 - 1000 ln/h
 Resolution  < 0.3% of range span
 Reproducibility  better than ± 0.3% of range span

Data display, inputs and outputs

User Interface LC display (40 characters x 16 lines) + bar graph
Plaintext description of instrument status as well as digital status output
Language: switchable between English & German
Instrument Status Plaintext description on the LC display as well as categorization into one of the following states
Analog signal output Galvanically isolated analog output
Available output levels:
• 0-20 mA or 4-20 mA
• 0-20 mA limited (current limited from 0 to 20.5 mA)
• 4-20 mA limited (current limited from 3.8 to 20.5 mA)
• 4-20 mA with superimposed instrument status (NAMUR NE 43 compliant)
• Test signal levels: 0 mA, 4 mA, 10 mA, 12 mA & 20 mA
Digital outputs 3 configurable, floating contacts for instrument status and/or
threshold monitoring
Default configuration: Instrument status (NAMUR NE 107 compliant):
Analog input (optional) 0(4) - 20 mA input (galv. isolated) for optional external setpoint control



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pControl 2F | Backpressure Controller


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Product Data Sheets

      pdf pControl 2F | Backpressure Controller

Technical specifications subject to change without notice

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