How the ControlPak Improves Pressure Control, Stability, and Consistency When Using an External Gas Source
September 4, 2026
When you’re performing repeated or higher-pressure calibrations with an external gas source, having enough gas capacity is only part of the equation. You still need precise control at the device under test.
That means being able to reach the exact test point, maintain pressure stability while verifying the instrument, and rely on your equipment to perform consistently throughout the calibration.
Field technicians regularly point to controllability, stability, and consistency as some of the most important parts of their pressure calibration setup. The right calibration setup gives you all three.
Precise Pressure Control Where You Need It
The Ralston QTVC-EN ControlPak Pressure Controller gives you precise control over an external compressed gas source, right at the device under test, for applications ranging from low-pressure differential testing to higher-pressure calibration.
Here are four ways the ControlPak supports field calibration when you’re working with an external gas source.
1. Fine Control When Small Pressure Differences Matter
Small changes in applied pressure can make a meaningful difference when you’re calibrating a pressure transmitter or setting a pressure pilot.
One natural gas technician described using simulated pressure to set pilots that control pipeline pressure. In some applications, he sets equipment within half a psi of the desired setpoint.
Another technician described his department as “the cash register” because its measurements help determine how much gas the company receives and sends. As he put it, a measurement discrepancy can mean “giving it away for free”.
The ControlPak’s pressure-balanced fine adjustment gives you precise local control to dial in and hold the test pressure while you verify the instrument.
2. Pressure Stability Throughout the Test Setup
Precise adjustment only helps if the pressure remains stable at the test point.
With compressed gas, temperature changes can cause pressure to change as the system settles. Longer hoses and larger internal volumes increase the amount of gas affected, making pressure stability more difficult to maintain.
The ControlPak works with Ralston Quick-test™ Microbore Hoses, designed to keep compressed gas volume low and reduce temperature sensitivity.
This is especially useful when the external gas source is some distance from the device under test. The ControlPak can stay at the calibration point while low-volume hoses connect it to the external source, helping maintain stable pressure throughout the setup.
3. A Consistent, Repeatable Calibration Setup
One technician rated consistency a “9 or 10 out of 10”, explaining that he expects his calibration equipment to perform reliably every time he uses it.
The ControlPak is part of the Ralston Quick-test™ System, which uses low-volume hoses, adapters, and fingertight connections to connect calibration equipment to a wide range of process connections.
Using the same pressure controller and connection system across instruments and test locations helps standardize the setup, reduce unnecessary setup steps, and create a more repeatable calibration process.
4. Portable Control Without Limiting Gas Capacity
Because the ControlPak separates pressure control from pressure generation, you can choose an external nitrogen source based on the pressure range, number of calibrations, and gas capacity your work requires.
For repeated high-pressure calibrations, that might be a larger cylinder mounted in the truck. At a plant, shop, or other fixed location, it could be an existing nitrogen supply.
At just 8.71 lb (3.95 kg), the ControlPak can go to the device under test while the larger gas source stays where it makes sense for the application. This gives you the gas capacity required for the work without giving up precise, portable control at the test point.
Better Control for Compressed Gas Field Calibration
An external nitrogen source can provide plenty of pressure, but turning that pressure into stable, precise calibration points requires a different kind of control.
The ControlPak lets you bring that control directly to the device under test, helping you make fine adjustments, maintain pressure stability, and use a consistent setup from one calibration to the next.
Combined with low-volume Quick-test hoses and an external gas source sized for the application, it gives you a portable pressure control setup for repeated and higher-pressure field calibration.
When your calibration process already includes an external compressed gas source, the ControlPak helps you make better use of the pressure source you already have.
See the ControlPak in action with this quick video overview of its setup and pressure control.
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