Products / Water Draw Systems
Waterdraw Pipe Prover Calibration Systems
A water draw system is used to determine the base volume of a pipe prover by drawing water through it and collecting it in certified volumetric reference vessels. Lonetti manufactures complete water draw systems — reference vessels, pump skid, valving, and instrumentation — built to API MPMS Ch. 4.9 and OIML R117, with system uncertainty as low as ±0.02%.
What is a water draw calibration system?
Water draw is the procedure for calibrating pipe provers (also called small-volume provers or unidirectional provers). Water is passed through the prover between detector switches and collected in certified prover tanks. The true base volume is computed from that draw, establishing the reference for all subsequent custody transfer measurements through that prover.
Water draw system specifications
| Method | Volumetric (API MPMS 4.9.2) · Gravimetric (API MPMS 4.9.3) |
|---|---|
| Reference vessels | Lonetti 304 SS prover tanks, ±0.025% class |
| Vessel sizing | Typically 1,000 L – 5,000 L |
| System uncertainty | ±0.02% – ±0.05% (configuration-dependent) |
| Standards | API MPMS Ch. 4.9 · OIML R117 |
| Mounting | Trailer · skid · permanent installation |
What standards apply to water draw systems?
API MPMS Chapter 4.9 (Calibration of Provers) and OIML R117 (Dynamic Measuring Systems for Liquids). Reference vessels are calibrated per OIML R117 and NIST Handbook 105-3.
When do I need a water draw system?
- Pipe prover commissioning: Initial base-volume determination on new unidirectional or bidirectional pipe provers.
- Periodic recalibration: 5-year recalibrations required by API MPMS and many regulatory regimes.
- Custody transfer audit: Independent verification of base volumes for fiscal metering audit trails.
Frequently asked questions about water draw systems
Volumetric versus gravimetric water draw — which is better?
Both are accepted by API MPMS Ch. 4.9. Volumetric is faster and uses certified reference vessels (Lonetti prover tanks). Gravimetric is slightly more accurate and uses a calibrated scale, but requires more setup. Lonetti systems support both methods.
Can the system be trailer-mounted?
Yes. Trailer-mounted, skid-mounted, and permanent installations are all available. Trailer-mounted systems are common for service providers who calibrate multiple pipe provers on rotation.
Contact Lonetti
Email: info@lonetti.com.ar · WhatsApp: +54 9 11 2788 4190 · Request a quote