DIY Gas Mixing Setups with Alicat Instruments

The art of creating precise gas mixtures is the backbone of thousands of industrial and commercial applications, from welding and chemical synthesis to food packaging and semiconductor manufacturing. Yet, it is by no means easy. Small deviations in critical factors like flow, pressure, temperature, or gas properties can destroy a mix and affect results downstream.

So, continuing our hypothetical, you get yourself some help. A premixed gas cylinder offers convenience at a cost, but requires storage, handling, and doesn’t account for different composition requirements, say a 75% – 25% mix for those unwieldy materials.  If you had a way to mix shield gas on-site, you could create your own composition, provided you had a system to accurately control mix ratios in real-time.

So what’s the right approach?

Gas mixing isn’t a fixed science; it’s more of an engineering dilemma with many valid solutions that depend heavily on the required accuracy, system complexity, and process variability. In cases where composition needs change with conditions—and a static pre-mix isn’t sufficient, but a fully automated system may be overkill—a DIY approach becomes an attractive middle ground.

While Alicat^® offers complete, automated FusionFlow™ gas blending instruments, this article focuses on a flexible alternative: building DIY gas mixing systems using Alicat Scientific’s Laminar DP flow and pressure instruments and their compatible software tools.

Whether mixing a single pair of gases or coordinating a larger multi-channel setup, Alicat mass flow and pressure devices support gas mixing by providing fast, accurate control, wide multigas capability, and straightforward integration with automation systems.

COMPOSER allows users to define custom gas blends with up to five constituents at 0.1 percent resolution. Up to 20 custom gas mixtures can be stored internally, making it easy to move between processes without interrupting work or reconfiguring external software.

Each selected gas or custom mixture maintains full NIST-traceable accuracy. Alicat’s laminar differential pressure technology automatically adjusts for gas properties, ensuring the calibrated accuracy applies across every pure gas and mixed blend stored on the device.

This connectivity is especially valuable in DIY gas-mixing and multi-gas delivery systems, where multiple gas streams must be controlled independently but operate as a coordinated whole.

In one application, a user built a fuel-cell test stand requiring backpressure control while keeping hydrogen, air, and purge gas flows separated. Although the gas streams were not physically mixed upstream, they were digitally coordinated to maintain precise flow rates, pressure balance, and stable operating conditions at the point of use.

By connecting multiple mass flow controllers, pressure controllers, and backpressure regulators through a shared BBX network, the user was able to power, monitor, and adjust each device from a single control interface. This approach reduces wiring complexity, simplifies system expansion, and makes it easier to add or reconfigure gas lines as test requirements evolve.

FlowVision MX provides an easy-to-use software platform for coordinating multi-channel gas mixing systems. Users can configure up to ten mass flow controllers, set mixture ratios, and adjust total or individual gas percentages from a single interface.

The software supports saving and reloading mixtures, logging performance data, and reviewing mixture accuracy over time. Its built-in controls make it easy to script automated sequences or make real-time adjustments during testing.

FlowVision MX runs on standard Windows systems and integrates directly with Alicat instruments, offering a low-cost way to manage multi-gas setups without custom programming.

Digital flow totalizers for tracking delivered volume

Alicat instruments include an integrated digital totalizer that records the total amount of gas dispensed since the last reset. Users can view cumulative flow, elapsed time, and peak flow directly on the device or over serial communication, making it simple to monitor batch runs or long-duration tests. 

In one application, the Flying Apple Space Technologies (FAST) team—a group of Nevada based students and researchers dedicated to high-altitude projects—took this capability into the field. While preparing for a weather balloon launch on the road, the team used a portable Alicat flow meter to precisely totalize helium and hydrogen during filling. Real-time totalization allowed them to stop the fill at exactly the right moment, preventing overfilling and ensuring a safe launch, without the need for a fixed lab setup, or cumbersome equipment.

Batch dispensing for precise dosing

With batching enabled, controllers automatically dispense a defined gas volume at the user’s chosen flow rate and close the valve once the target amount is reached. This supports repeatable dosing steps in gas-mixing sequences, calibration routines, or automated test cycles.

Analog alarms for real-time safety and process limits

Mainline devices can be configured with high or low analog alarms that trigger when flow or pressure exceeds defined thresholds. These alarms integrate easily with PLCs or safety interlocks, providing another layer of protection and process control in multi-gas systems.

LabVIEW provides a graphical programming environment widely used for instrument monitoring, automation, and test development. Alicat offers ready-made virtual instrument drivers that let users drop flow or pressure blocks directly into LabVIEW workflows with minimal coding.

These drivers simplify data acquisition, device configuration, and device commands, making it straightforward to integrate multiple Alicat instruments into existing LabVIEW test stands or research setups.

This makes it easy to prototype mixing strategies, configure multi-channel systems, or incorporate Alicat instruments into larger simulation frameworks for testing or real-time control.

Wide control range:

• Precise control from 0.01 – 100% of full scale, with flow ranges from 0.5 SCCM to 12,000 SLPM for both trace and high-flow applications.

Gas Select™ flexibility:

• An onboard, NIST-traceable library of 90 – 130 gases allows users to switch gases instantly without recalibration.

Fast, multivariate response:

• Rapid stabilization (as low as 30 ms) with integrated mass flow, volumetric flow, pressure, and temperature measurements.

Highly customizable integration:

• Compatible with common protocols including RS-232, RS-485, Modbus, and IO-Link, with options for IP66/67 environmental protection and IS‑Max™/IS‑Pro™ models for flammable or explosive gas areas—making Alicat devices adaptable to a wide range of operating environments.

Alicat supports gas mixing applications across hundreds of industries with instruments and software tailored to your system requirements.