Proven, Liquid-Free, Primary

Positive Displacement Gas Flow Measurement Technology

DryCal Technology

ProvenDryCal-webMesa Labs originally designed our primary gas flow standards for industrial hygiene applications requiring volumetric, NIST-traceable calibrations of air sampling pumps to within ±1% of reading accuracy. Ours were the first dry calibrators for the market, and were welcomed by industry professionals not only for their revolutionary, liquid-free convenience, but their accuracy, speed and push-button ease-of-use.

Over time, their continued success created a natural migration of our Proven DryCal® Technology to the most exacting uses. With ultra-low uncertainties of ±0.15% of reading standardized and broad flow ranges featuring an amazing 100:1 turndown, our proprietary technology is now the basis for superior gas flow measurement in semiconductor fabrication, pharmaceutical production, biotechnology research and development, aerospace development and many other critical applications.

Proven DryCal® Technology is a liquid-free gas flow measurement system that doesn’t rely on soap bubbles for measurement, oil or mercury to form a gas-tight seal, or non-primary thermal mass flow readings that must be backward calculated to obtain volumetric flow.

Our patented technology uses a nearly-frictionless graphite composite piston housed within a flow measuring cell of precisely quantified dimensions. A bypass valve opens to receive gas flow, and then closes to initiate a flow measurement. When closed, the gas is diverted to the flow measuring cell, entering beneath the piston. As it enters the flow cell, the piston must move with the flow stream. Primary flow is determined through use of a timed path of known distance.

At the same time, the gas being measured forms the gas-tight seal (or, viscous-seal). When the piston reaches the furthest point along the path of travel, a volumetric flow measurement has been electronically recorded. The gas is released from the flow cell, allowing the piston to drop to the bottom. The system instantly resets in time for the next reading.

Accurate, reliable and convenient. Not to mention clean.

Our reliable technology is a ‘positive displacement’ piston prover design, an internationally-accepted platform that’s been the standard for obtaining primary gas flow measurements for over a century. Even so, our system has several unique attributes that not only set it apart from other piston provers, but from other gas flow measurement standards in general.

It starts with the fact that our patented technology is both primary and dry. And it’s even pretty small. In fact, it’s extremely portable – whether by hand, cart or standard freight carrier. Because our system’s volumetric-based, it’s not subject to drift (it derives its accuracy from the flow cell’s dimensions, which don’t change over time or due to environmental conditions), which means it’s ready to perform right out of the box – accurately. That’s why we like to think of our technology as “shippable precision.”

Then there’s the simple push-button operation, which enables hands-free measurements, leaves little room for user-error or interpretation, and requires only minimal training. Virtually anyone in your organization can step up to the plate and perform calibrations in a pinch.

But perhaps the biggest thing about our Proven DryCal® Technology is in its name: Proven. Mesa Labs ISO 17025 accreditation by the National Voluntary Laboratory Accreditation Program (NVLAP) – the third party accrediting body of the National Institute of Standards and Technology (NIST) – provides the backing you need to feel confident in Mesa.

The Primary Standard Difference

Gas flow measurement is elusive. The key to understanding gas flow measurement is in recognizing that there are seven SI base units (International System of Units) that have been quantified and refined worldwide and their precise values are unlikely to change. These SI base units are also called the “primary units of measure” and include length, time, mass, electric current, thermodynamic temperature, amount of substance and luminous intensity.

Our patented technology is primary because it measures gas flow using the SI base units of length and time in order to derive flow: The interior diameter of our glass flow cell; the length of piston travel within this cell; and the time it takes the piston to travel this known distance. With Proven DryCal® Technology products, customers receive accurate, directly traceable primary flow measurements that are fully supported by our leading laboratory accreditation. Pressure and temperature transducers in the flow stream allow conversion of the volumetric flow to standardized conditions. This differs from other gas flow meters and secondary systems that measure gas flowinferentially by measuring gas properties, such as energy transfer or heat transfer.

Since there’s no SI base unit for the direct measurement of gas flow, flow is best determined by measuring the time it takes to positively displace a known volume of gas. Volumetric piston provers, such as Mesa Labs products featuring Proven DryCal® Technology, are based on a century-old platform that’s still considered by many – including national labs – to be the most desirable method of measuring gas flow, since the results are directly traceable to the SI base units. And unlike other piston provers, Mesa Labs gas flow standards do it without water and soap bubbles, oil, or hazardous mercury. Our patented Proven DryCal Technology is truly primary because its accuracy is based upon the SI base units of length and time in order to derive volume: The interior diameter of our glass flow cell; the length of piston travel within this cell; and the time it takes the piston to travel this known distance. With Proven DryCal Technology products, customers receive accurate, directly traceable primary flow measurements that are fully supported by Mesa Labs leading ISO 17025 laboratory accreditation.

Please visit our blog for updates regarding technical product and application resources in addition to announcements. Stay up to date with everything that is happening with Mesa by subscribing to our Flowlines Newsletter to receive information from our team of flow experts. Mesa Labs believes in the Primary Difference, and we’ve proudly staked our reputation on it.

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