Precision Oval Gear Flow Meter

Three things change on the precision build. First, the rotor-to-chamber clearance is held to a tighter mechanical tolerance, which lowers the slip-flow that otherwise grows at low end of the flow range. Second, each meter is individually diesel-oil wet-calibrated on the factory loop per JJG 667-2010 across multi-point coverage of the published viscosity range, not just one nominal point. Third, the published flow-range tables narrow at the low end; for example, DN200 at 0.6-2 mPa·s tightens to 170-340 m³/h on the precision build vs 68-340 m³/h on the standard build. The build offers four precision sub-tables (DN10-DN200 × two viscosity range × standard plus high-viscosity precision) so the buyer can verify the working flow falls inside a range that holds ±0.2 % of rate per individual calibration.

Honest answer: no, and any vendor claiming otherwise ex-factory is overstating. The meter is engineered to ±0.2 % of rate per individual wet calibration, which is engineering-tighter than the ±0.5 % of rate standard grade and tighter than most general-purpose oval-gear pages on the market. But OIML R 117 (the international liquid-volumetric custody-transfer recommendation), MID MI-005 (the EU directive on fuel meters), and API MPMS Chapter 5.2 (the US custody-practice reference) are notified-body or weights-and-measures approvals that the buyer arranges with the local metrology authority; the factory does not ship them. If the project requires fiscal-billing approval for petroleum custody, go to a Coriolis mass meter with ±0.1 % of rate and the corresponding notified-body cert path. This page is the right pick when the service needs engineering-tighter accuracy on a volumetric chamber meter at oval-gear hardware cost, without the custody-approval paperwork burden.

Coriolis is the ±0.1 % of rate custody king on petroleum custody; mass-flow direct, viscosity-independent at the mass-flow level, tolerant of two-phase, and the standard pick for refinery and pipeline custody where the contract demands notified-body certification. The trade is hardware cost. A precision oval-gear node is typically two to three times less expensive than a same-DN Coriolis on petroleum service. The precision oval-gear lane is for buyers who do not need ±0.1 % of rate, do want hard-pulse volumetric chamber metering (each rotor revolution counts a fixed volume; count the pulses, count the liters; intrinsic auditability), and want lower per-node hardware cost across a multi-meter terminal or fuel-dispense skid. Use Coriolis when the contract reads ±0.1 % of rate or OIML R 117 custody approval. Use this page when the service is small-batch billing, lab dosing, or premium fuel dispense on clean Newtonian liquid and ±0.2 % of rate per individual calibration is contract-acceptable.

Different gear geometry, different pressure range, different buyer. The mini-bore meter counterpart on this site uses helical or spur gear geometry; not oval; in a DN5 to DN25 small-bore body, at pressures up to PN40 MPa and PEEK or PTFE wetted-parts options for aggressive chemical-dosing, hydraulic-test-bench, and lab service. It uses a data-plate K-factor on every body. This precision oval-gear page uses oval-rotor geometry in a DN10 to DN200 conventional body, with PN1.0 to PN6.3 MPa cast iron / cast steel / 304 / 316 stainless wetted parts, and ±0.2 % of rate by individual diesel-oil wet calibration across four published viscosity range. Decision rule: go to the mini-bore page when the service is DN5, pressure above PN6.3 MPa, PEEK or PTFE chemistry, or a high-pressure hydraulic test bench. Route here when the service is DN10 and above, conventional body materials, and the buyer wants a published ±0.2 % of rate accuracy class on the volumetric chamber meter.

Lead time is 5 to 7 business days from the factory. Each order ships with the meter wet-calibrated on the factory loop, an ISO 9001 calibration certificate referencing the diesel-oil multi-point procedure per JJG 667-2010, a mill cert traceable to heat number on the wetted body material, the selected counter or transmitter package factory-mounted, and the flange or thread connection per the order code. A per-meter K-factor calibration certificate with the full multi-point dataset is available by quote (engineering returns the cert format and the additional lead-time delta on request); the standard ISO 9001 calibration cert that ships with every meter is sufficient for most engineering acceptance. Custody-transfer notified-body paperwork (OIML R 117, MID MI-005, weights-and-measures stamps) is buyer-arranged separately.