A Lonetti prover tank is a precision-calibrated stainless steel vessel used to verify the accuracy of liquid flow meters. A known volume of liquid passes through the meter under test and is collected in the prover tank — if the meter reading matches the tank's certified volume, the meter is accurate.
Lonetti has manufactured prover tanks in Buenos Aires since 1960. Today they serve at petroleum terminals, refineries, pipeline takeoffs, and national metrology institutes across 47 countries — most often in custody-transfer applications where measurement accuracy is legally required.
Every tank is built to customer specification. Capacity, geometry, valve configuration, and mounting are determined by the application: flow rate, fluid properties, accuracy class, and applicable standards. Standard configurations ship in 8–14 weeks.
6 properties that define a Lonetti prover tanks.
Specification points worth comparing against any other supplier — accuracy class, material grade, standards compliance, and configurability.
±0.05% accuracy
Volumetric accuracy of ±0.05% or better. Calibrated by INTI, traceable to international metrology standards.
304 / 316 stainless steel
Standard construction in 304 SS. 316 SS or specialty alloys available for aggressive media.
OIML R117 & API MPMS 4.4
Designed and manufactured to OIML R117, API MPMS Chapter 4.4, and NIST Handbook 105-3.
50L to 5,000L+ capacity
Manufactured from 50 liters to well over 5,000 liters. Larger configurations available on request.
Stationary, skid, or trailer
Fixed, skid-mounted, or trailer-mounted configurations to suit field, terminal, or workshop deployment.
Sight glass & scale options
High-resolution sight glasses with engraved scales, optional digital level transmitters.
Built to your spec, certified to ours.
These are the parameters our engineering team needs to start a quote. For a full technical datasheet, request the PDF.
Download full datasheetWhere Lonetti prover tanks go to work.
The same engineering platform serves several distinct use cases. Configuration varies; accuracy class doesn't.
Custody transfer
Calibrate fiscal flow meters at refineries, marine terminals, and pipeline takeoffs.
Meter proving
On-site or workshop verification of positive-displacement and turbine meters.
Dispenser calibration
Truck-loading rack and dispenser verification under regulatory audit.
Pipe prover waterdraw
Base volume determination of pipe provers via certified water draw.
Workshop, field, and deployment.
Common questions.
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