Sample Flow Control | Kaizen Controls And Automation

Why Pressure Stability Matters in Analyzer Systems

Gas analyzers are extremely sensitive to pressure changes. These fluctuations can:

Cause collisional (pressure) broadening in spectroscopic analyzers
Shift calibration baselines, especially in trace gas detection
Alter sample flow rates, impacting measurement reproducibility

Whether you're working in emissions monitoring, process control, or R&D, inconsistent pressure equals unreliable data.

Forward Pressure Controllers: Stable Delivery to the Analyzer

Alicat’s forward pressure controllers regulate downstream pressure from the gas source, ensuring a constant inlet pressure to the analyzer. This is vital for:

TDLAS systems, where even slight pressure drift affects spectral line fitting
FTIR and UV analyzers, where density changes impact absorption

These controllers isolate your analyzer from upstream fluctuations and maintain reliable input conditions.

Back Pressure Controllers: Consistent Internal Analyzer Pressure

Used downstream of the analyzer, Alicat’s back pressure controllers stabilize pressure within the sample cell or analyzer chamber by automatically venting excess gas or adjusting draw rates.

This ensures:

Stable signal response for IR and UV systems
Reliable performance in systems with downstream vacuum or inconsistent exhaust pressures

Alicat Backpressure Regulator at work

Why Replace Outdated VA (Variable Area) Flow Meters?

Many analyzer systems still rely on rotameters (VA meters) for flow monitoring. While simple and inexpensive, they come with serious limitations that can affect system performance:

1. They Stick or Drift

The mechanical float inside VA meters can stick due to contamination, vibration, or incorrect mounting, leading to inaccurate or unreadable flow rates. Over time, these meters become less reliable and harder to maintain.

2. No Remote Flow Verification

VA meters require manual, visual inspection—meaning no remote access, no automated alarms, and no integration with control systems. In critical or hazardous environments, this is a major drawback.

3. No Compensation for Process Conditions

VA meters are highly dependent on pressure and temperature, meaning the displayed flow often doesn’t reflect actual conditions. Alicat devices automatically compensate for both, providing far more accurate readings.

4. No Data Logging or Traceability

There’s no built-in logging or digital output in a rotameter. Alicat controllers, on the other hand, support real-time diagnostics, digital communication protocols, and full integration with PLCs or SCADA systems.

Multivariable Functionality in One Compact Instrument

Alicat devices are true multivariable controllers that measure and report:

Mass flow rate
Volumetric flow rate
Pressure
Temperature
Real-time diagnostic data (valve position, alarms, and more)

This eliminates the need for multiple instruments, reducing installation cost, wiring complexity, and maintenance overhead.

Fast Response and High Precision

Alicat controllers respond in milliseconds, adjusting dynamically to process changes. This leads to:

Tight synchronization with analyzer measurements
Reduced lag during startup or gas switching
Greater repeatability and confidence in data

Boosting Reliability, Reducing Costs

Whether you’re upgrading from a manual flow setup or building a precision analyzer system from scratch, Alicat’s solutions offer:

Improved process stability through pressure and flow control
Remote monitoring and automation capabilities
Lower total cost of ownership with multivariable functionality
Higher analyzer uptime and fewer field visits

Ready to Upgrade Your Analyzer System?

If your system still depends on manual flow meters or suffers from pressure swings, Alicat’s pressure and mass flow controllers provide the precision, flexibility, and connectivity you need. Contact us today to explore the best controller setup for your analyzer system—we’re here to help you increase performance, reduce downtime, and future-proof your instrumentation.