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RH Systems - Speed, Precision, and the G3 Low Frost Point Generator

April 28, 2026

RH Systems - Speed, Precision, and the G3 Low Frost Point Generator

In the world of high-stakes metrology, low humidity is the ultimate test of patience. Anyone who has worked in a lab knows the drill: you set your target frost point, and then you wait. You wait for the lines to purge, you wait for the system to stabilize, and sometimes you wait 24 to 48 hours just to get a single calibration point.

Bob Hardy decided it was time to stop waiting.

"The G3 doesn't waste your time," Bob says. "It solves the two biggest problems in low humidity generation: speed and accuracy."

Here is a deep dive into the G3 Low Frost Point Humidity Generator and how it is redefining what’s possible at the extreme low end of the scale.

Redefining the "Low End"

The G3 isn't just a standard humidity generator; it is a specialist designed for the most demanding regions of the psychrometric chart. It generates gas from a +10 °C dew point all the way down to -100 °C frost point (and lower).

Whether you are calibrating dew point sensors, chilled mirror hygrometers, or high-altitude aerospace instrumentation, the G3 provides a level of stability that was previously reserved for massive, stationary primary standards.

The Speed Revolution: From Days to Minutes

The most jarring shift for new G3 users is the clock. Traditional low-humidity generators are notorious for their sluggishness.

"It usually takes a long time to get to a low value," Bob explains. "With the G3, we can usually get down to a low humidity value in that same range in a matter of half an hour to an hour."

By eliminating 95% of the wait time, labs can increase their throughput exponentially, turning a two-day calibration process into a morning's work.

Under the Hood: The Tech that Obliterates Drift

How does it get there so fast? Bob broke down the internal innovations that make the G3 a "Problem Obliterator":

1. The Vacuum Chamber & Stirling Coolers

The G3 utilizes a vacuum chamber for total thermal isolation. By removing the air around the internal components, RH Systems eliminates the risk of water vapor permeation from the outside environment into the gas path. Inside that chamber are Stirling Coolers. Unlike traditional refrigeration, these use no fluids or refrigerants. They provide direct contact cooling to the saturator, allowing it to reach extreme sub-zero temperatures almost instantly.

2. Advanced Thermal Gradient Control

Accuracy at -100 °C requires more than just cold; it requires control. The G3 features temperature sensors at the top and bottom of the saturator.

  • Redundancy: Two sensors at the top ensure the primary control temperature is always verified.

  • Gradient Management: By monitoring the bottom of the saturator, the system prevents "undesired effects" caused by warm gas entering the chamber. The G3 actively manages the thermal gradient to ensure the gas is perfectly saturated at the exact temperature intended.

3. Independent Multi-Channel Flow

Efficiency doesn't stop at the generator. The G3 features three independent gas flow output paths. This allows you to connect multiple devices simultaneously, each with its own independent flow rate.

Data Management: Total Transparency

A calibration is only as good as its documentation. The G3 acts as a data hub for your entire lab setup.

  • Simultaneous Logging: It collects data from the generator and all connected instruments (via Serial or USB) simultaneously.

  • Live Graphing: The touch-zoom screen allows you to see real-time trends, standard deviations, and mean averages for every device in the loop.

  • Big Data: All information is funneled into comprehensive log files, ensuring your audit trail is bulletproof.

Built for the People Who Do the Work

Bob and the RH Systems team designed the G3 with the "Maintenance Job" in mind. The entire system is mounted on a slide rail system. Simply release the stabilization foot, pull the tab, and the entire internal assembly slides out. "You’ve got full access to everything—the vacuum chamber, the components—all without the frame getting in your way," says Bob.

See It for Yourself

RH Systems is about more than just spec sheets; it’s about community. Bob is so confident in the G3 that he encourages prospective users to talk to the people who already own them.

"Go visit someone who has one—we’ve got a lot of people out there using these now," Bob suggests. "I’ve even been known to do a little WhatsApp video chat now and then to show people how it works."

Ready to stop waiting for your frost points to stabilize? Contact us to setup a call. We’ll also exhibit the G3 at many conferences—come by and see it in action!