Using a portable flow meter to check your equipment
Portable mass flow meters are ideal for quickly and accurately checking on your equipment to make sure it is working properly. Several different types of portable meters ranging from standard gas meters to complete on-the-go calibration kits make flow verification, validation, and calibration easy to perform for a variety of applications. These three interrelated processes can often be confused, but each is distinct and varies in importance depending on the application. In this article, we briefly summarize the key differences between verification, validation, and calibration, and describe the use of portable flow meters for each.
Verification describes the evaluation of equipment to determine whether it is still operating within its originally stated specifications. Typically, this is an operation performed on equipment or a process some time after its initial purchase in order to verify that it is still performing as designed. However, verification is also sometimes required to verify instruments post purchase but pre-installation. In-situ flow verification involves temporarily inserting a flow meter into the process and measuring parameters such as flow rate and pressure.
Portable mass flow devices are particularly well-suited to enable quick performance of verification and minimize process downtime. For example, Alicat’s Portable Calibration Unit (PCU) might be employed for in-the-field verification of flow meters in gas panels. The advantage of the PCU in this instance is that it contains three mass flow meters covering a wide flow range, allowing for the single case to be used easily for rapid verification of multiple process parts involving varying flow rates.
A simpler example might involve using a single battery-powered portable MWB mass flow meter, which is ideal for processes involving low system pressures and requiring minimal effect on the flow rate of the process fluid. Refer to this article to learn more about the differences and advantages of MWB versus other portable flow meter models.
Whereas system verification involves periodic checking of each equipment piece to ensure its proper function, validation instead focuses on a holistic system evaluation to determine whether it is performing, as a whole, according to its intended purpose. While system verification is typically spurred on by internal needs, validation is usually necessary to ensure that the whole system operates according to external requirements and regulations.
For example, the EPA closely regulates the output of stack gases at power plants and refineries. Flow verification might be used to confirm the maximum flow rate of a valve in the analyzer system, but flow validation would be used to ensure that the analyzer system as a whole delivers a throughput that allows a level of gas analysis that meets or exceeds the EPA requirements.
A set of processes operating within proximity of one another, perhaps out in the field or in a plant, could all be validated using a portable mass flow meter. The MB-Series is battery powered and lasts up to 18 hours, ensuring that multiple processes can be validated in a short amount of time and with minimum system impact. While the MB-Series is compatible with 98 different gases, applications flowing corrosives may require the MBS-Series as it is compatible with several aggressive gases.
Calibrations are performed to ensure that instrument measurement accuracies conform to known external standards. There are two types of calibration standards: primary, which refers to a universal measurement reference standard; and secondary, which refers to the use of an instrument which has been directly calibrated to the primary standard.
Portable flow meters with NIST-traceable calibration standards are excellent for use as secondary transfer standards in the field and can be used for rapid system calibration. Alicat’s high accuracy calibration portable flow meters are all NIST-traceable and operate across wide flow ranges, most with a 10,000:1 measurement range. A single portable flow meter is sufficient for many applications, but for a complete rapid calibration solution for a wider measurement range such as 100,000:1, the PCU is recommended.
Alicat’s various portable mass flow solutions offer rapid response times and live readouts of mass and volumetric flow rates, pressure, and temperature. These features make them ideal for in-situ verification, validation, and calibration needs by providing necessary information quickly and minimizing both system impact and downtime. Contact our Applications Engineers to find the right solution for your application.