Fluid Metrology Calibration Services - Liquid Hydrocarbon Flow Calibrations

Liquid Hydrocarbon Flow Calibrations
18030C

NIST has four primary standards that are used to calibrate Liquid Hydrocarbon Flow meters: 1) The Small Cox Bench; 2) The Large Cox Bench; 3) The 2 L Hydrocarbon Liquid Flow Standard (2 L HLFS); and 4) The 20 L Hydrocarbon Liquid Flow Standard (20 L HLFS). The first two primary standards (i.e., the Small and Large Cox Benches) are dynamic standards that determine the time-averaged flow by measuring the time required to collect a measured mass of liquid diverted into a collection tank. For volumetric flow meters (e.g., turbine meters, positive displacement, etc.) the fluid density at the meter being calibrated is determined so that flow can be reported in volumetric units. The latter two primary standards (i.e., the 2 L HLFS and 20 L HLFS) are piston provers. Flow determination is based on the piston displacing a known volume of liquid in a measured amount of time. Table 1 shows the flow range and expanded uncertainties (i.e., uncertainty at the 95 % confidence interval or k = 2) for all four standards

Table 1: Four flow standards used for hydrocarbon liquid flow

Calibrations of hydrocarbon flow meters are performed using a surrogate liquid for JP-4 and JP-5 jet fuels. Preferred piping connections are A/N fittings, and National Pipe Threads up to 5.5 cm (2 in) in diameter.

A normal flow calibration includes five different flows, with five averages of the meter readings and the standard flow made at each set point, with this entire test sequence repeated on a second occasion to assess reproducibility. It is helpful if the customer specifies the flow set points and the instrumentation requirements of the meter (pressure, temperature, full scales required, etc.). We deliver a calibration report that includes an uncertainty analysis for the flow meter calibration factor. (Note that the uncertainties in Table 1 do not include reproducibility of the meter being calibrated.) NIST reported uncertainties include the uncertainty of the primary flow standard (see Table 1) as well as uncertainty attributed to reproducibility of the meter under test and the uncertainty of any instrumentation associated with measuring the flow meter output.

Calibration fees for this and other services can be found in the Calibration Fee Schedule. To read more about our facilities, see the NIST Special Publication 250-1039.

Turnaround time for a single flow meter is approximately 4 weeks:
1. Allow 2 weeks for shipping;
2. 1 week for set-up and data collection; and
3. 1 week for report writing and review.

To have your flow meter calibrated:

1. Contact Sherry Sheckels to schedule your calibration dates;

2. Details on ordering instructions, purchase orders, shipping, and Service ID Numbers, can be found at NIST's Calibration Services.