Smith Meter calibrators change the drive ratio between the PD meter gear train and the meter-driven accessories, so registration can be adjusted manually to match the actual gross volume displaced under operating conditions. When driven by a thermal system (ATC), the calibrator changes the ratio with product temperature to give net registration (see the ATC temperature compensator, SS01038). The calibrator uses two overriding clutches and an eccentric; adjusting the eccentricity varies the ratio by up to 11% in total (1 input revolution gives 1 to 1.11 output revolutions).
Key specifications
Adjustment range: Up to 11% total; about 4-5% used on most gross-registering meters, about 8-9% used by ATC calibrators for net registration
Manual adjustment: Each dial notch = 0.0005 (1/20 of 1%); + direction decreases registration, - increases it. Six threads exposed on the adjusting screw is the suggested starting point for a new calibrator on a 96% geared meter
ATC adjustment: Each notch = the product's coefficient of expansion per °F (for example 0.00046 per notch for 38° API)
Mechanism: Eccentric arm on a pivot pin, positioned by an adjusting screw (manual) or thermal plunger (ATC); crank arm, sliding blocks, center disk, cam disk and outer ring with roller clutches
Maintenance: Light oil (SAE 10) after about five hours of operation, then about twice a year
How to specify / order
SS01030 is a principle-of-operation bulletin and gives no model code or part numbers. Calibrator part numbers depend on the meter, so provide:
Meter model, size, pressure rating and serial number
Manual (gross) calibrator, or ATC calibrator for net registration (state product, gravity or coefficient of expansion and temperature range for ATC)
Current meter gearing (for example 96% or 100%) and units of registration
Meter-specific calibrator parts are also listed individually in the FMS store by part number
Bulletin notes: the text reads "about 4 or 5% or most gross registering meters" (of most) and prints API as "APl"; no other errors found.
Pricing and lead time are quoted per configuration. Send the model number (or the details above) with your meter model and serial number to Flow Measurement Services for a quote. Specifications summarized from Smith Meter bulletin SS01030 Rev 0.2 (10/17); confirm current data with the factory before ordering.
Smith Meter (formerly FMC Technologies / TechnipFMC Measurement Solutions), now manufactured by Guidant. Flow Measurement Services supplies and services Smith Meter equipment.