High-Viscosity Oval Gear Flow Meter
200 to 2000 mPa·s heavy-fuel and resin service
±0.5 % of rate base; ±0.2 % of rate precision grade on the same rotor
DN10 to DN200, PN1.0 to PN6.3 MPa, −20 to +80 °C wetted span
1:10 turndown per body per viscosity range; zero straight-pipe required
- Dedicated high-viscosity rotor; lube oil, gear oil, resin, paint, polyol, molasses, chocolate, and warmed heavy fuel oil
- Diesel wet calibration on the factory loop per JJG 667-2010, ISO 9001 calibration cert, mill cert traceable to heat number
- Mechanical pointer build needs no power and no Ex cert; LCD electronic build adds pulse, 4-20 mA, or RS-485 Modbus output
- Out-of-scope: above 2000 mPa·s by quote; abrasive or particulate-laden liquid (go to Coriolis); ±0.1 % custody (go to Coriolis HFO)
High-viscosity rotor · viscosity 200 to 2000 mPa·s
Permanent loss 50 to 150 kPa at rated flow. Size service to 50–80 % of rated max for service life.
The LC-N series (LC-NA cast iron, LC-NE cast steel, LC-NB stainless); a dedicated high-viscosity rotor for 200 to 2000 mPa·s service: lube oil, resin, paint, polyol, food syrup, molasses, warmed heavy fuel oil. Two oval rotors meter four crescent-cavity volumes per revolution; zero straight-pipe required. DN10 to DN200, PN1.0 to PN6.3 MPa, −20 to +80 °C, ±0.5 % of rate base or ±0.2 % precision grade. Diesel wet-cal per JJG 667-2010. Ships 5–7 business days.
Benefits
- Dedicated 200 to 2000 mPa·s rotor: factory-tuned high-viscosity tooth profile and tip clearance, with published flow-range sub-range at 200-1000 and 1000-2000 mPa·s across DN10 to DN200.
- ±0.5 % of rate base, ±0.2 % of rate precision grade: precision grade (suffix -J) holds on the same rotor at 1:5 turndown; the ±0.5 % grade runs 1:10. Documented.
- Zero straight-pipe demand: chamber displacement is independent of velocity profile. Install directly downstream of elbows, valves, or pumps without flow conditioning.
- Cast iron, cast steel, 304 stainless, 316 stainless: matched to fluid chemistry and corrosivity. Iron and cast steel for petroleum and lube; stainless for resin, polyol, and food syrup.
- Diesel-loop wet calibration per JJG 667-2010: K-factor stamped on the data plate, ISO 9001 certificate, mill cert to heat number. Water calibration is forbidden on cast bodies.
Configure your build.
Pick line size, body material, working pressure, counter, and output. The configurator returns the PF-OG-LCN model code and a ballpark unit price; engineering replies with a sized quote within one business day.
Your Configuration
PF-OG-LCN-A50.2/A1-N
DN50, cast iron body, PN1.6 MPa, A1 pointer with six-roller totalizer and signal-output capability, mechanical-only (no transmitter), standard ±0.5 % of rate accuracy.
Estimated unit price
Verified after engineering review
$720
✓ Diesel-loop calibrated per JJG 667-2010
✓ ISO 9001 cert, mill cert to heat number
✓ Reply within 4 business hours
✓ ISO 9001 cert, mill cert to heat number
✓ Reply within 4 business hours
Typical applications
Four applications where the high-viscosity oval gear meter is the right pick.
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Lube oil and gear oil distribution
Tank-to-truck custody on ISO VG 100 to VG 460 oils at 200-1000 mPa·s. Cast iron body, mechanical pointer, billing without external power.
🍫
Resin, paint, and polyol batching
Polyester resin, alkyd paint, polyether polyol, PVA at 500-2000 mPa·s. 316 stainless body; pulse output to the batch controller.
🍬
Molasses, chocolate, and food syrup
Molasses 1000-2000 mPa·s, chocolate liquor 400-800 mPa·s, corn syrup 200-500 mPa·s. 316 stainless wetted parts; tri-clamp by quote.
⛓
Warmed heavy-fuel-oil bunker delivery
Bunker fuel oil C, 200-1000 mPa·s after tank-side preheat. Iron or cast steel body, ±0.5 % of rate billing.
Specifications
| Measurement principle | Volumetric positive-displacement; two interlocking oval-geared rotors with a dedicated high-viscosity tooth profile; 4 × crescent-cavity volume per rotor revolution; viscosity-tolerant, no Reynolds-number dependence, no straight-pipe requirement |
|---|---|
| Reference standards | JJG 667-2010 (China national metrological verification regulation for liquid volumetric flow meters); volumetric-PD conventions referenced in API MPMS Chapter 5.2 custody practice (buyer-arranged custody approval, not factory-supplied) |
| Line size | DN10 to DN200 (DN10, 15, 20, 25, 40, 50, 65, 80 light, 80 heavy, 100, 150, 200) on the standard high-viscosity body |
| Model code | LC-N series; LC-NA (cast iron, high-viscosity rotor) / LC-NE (cast steel) / LC-NB (304 / 316 stainless); full build per the §XIV selection matrix (e.g. LC-NA40.2/A1-GF-I = LC-NA cast iron, DN40, PN1.6 MPa, A1 counter + signal-out, GF-I 12 V pulse). Append −J for the ±0.2 % precision grade (LC-NA-J etc.) |
| Working pressure (PN) | PN1.0 / PN1.6 MPa (cast iron); PN1.6 / 2.5 / 4.0 / 6.3 MPa (cast steel and stainless) |
| Medium temperature | −20 to +80 °C (standard pointer build); −20 to +60 °C (LCD electronic build). Warmed asphalt and hot heavy-fuel-oil service above +80 °C goes to the high-temperature related page |
| Accuracy | ±0.5 % of rate (standard high-viscosity build); ±0.2 % of rate (precision high-viscosity grade, selection-code suffix -J) |
| Repeatability | ±0.05 to ±0.1 % typical on a freshly calibrated meter; published as engineering rule, not as a separate published row |
| Viscosity range | 200 to 2000 mPa·s on the dedicated high-viscosity rotor; two published flow-range sub-tables (200-1000 mPa·s and 1000-2000 mPa·s) across every line size; above 2000 mPa·s by quote |
| Flow range | 0.03 to 238 m³/h DN-dependent across the high-viscosity sub-ranges; for example DN50 carries 2 to 16.8 m³/h at 200-1000 mPa·s, DN100 carries 10 to 70 m³/h, DN200 carries 48 to 238 m³/h |
| Turndown | 1:10 per body per viscosity range on the ±0.5 % grade; 1:5 on the ±0.2 % precision grade |
| Permanent pressure loss | 50 to 150 kPa across the meter at rated flow on 200-2000 mPa·s service; engineering estimate from the error-and-pressure-loss curve, refined by quote at the specific operating point |
| Straight pipe requirement | None; volumetric chamber displacement is independent of upstream velocity profile (oval gear, unlike turbine, vortex, or DP primary) |
| Wetted material | Cast iron (general heavy-oil and lube service) / cast steel (higher-pressure refined fuel and process) / 304 stainless / 316 stainless (chemical, mild acid and alkali, food syrup); rotor in cast iron on iron and cast-steel bodies, stainless rotor on stainless bodies |
| Display / counter | Mechanical pointer + six-roller cumulative totalizer (A1 with signal-out, A passive, Z with zero-return shift reset); LCD electronic head with instantaneous + cumulative readout (ELZ build) |
| Output signals | Passive mechanical-only / pulse 3-wire 12 V (GF-I) / pulse 3-wire 24 V (GF-II) / 4-20 mA 2-wire or 3-wire (MF) / RS-485 Modbus RTU on the LCD electronic build only |
| Hazardous area | Ex d IIB T4 on the transmitter housing; mechanical-only pointer build needs no hazardous-area certification (passive, no electronics) |
| Ingress protection | IP65 standard on the electronic build; IP66 by special order |
| Power supply | Passive (mechanical pointer) / DC12V (GF-I, MF 2-wire) / DC24V (GF-II, MF 3-wire) on the electronic builds |
| EMC | EMC 2014/30/EU Annex II on the transmitter side |
| Connection / mounting | Flange JB/T 79~82-1994 (PN1.6 / 2.5 / 4.0 / 6.3 MPa); ANSI 150 / 300 / 600 lb to order. Rotor shaft must be installed horizontal regardless of pipe orientation |
| Applicable media | Lube oil, gear oil, hydraulic oil, heat-transfer oil at room ambient, resin, paint, polyol, PVA, glycol, organic solvent, molasses, chocolate liquor, corn syrup, honey, jam, warmed heavy fuel oil at room-ambient terminal storage; single-phase, particulate filtered upstream |
| Calibration | Diesel wet calibration on the factory loop per JJG 667-2010; ISO 9001 calibration certificate. Water calibration is forbidden on cast iron and cast steel bodies (water induces oval-rotor corrosion in shipping storage) |
| Lead time | 5–7 business days from factory |
Installation
Five field rules for a conformant install and a stable K-factor on high-viscosity service.
- Install an upstream particulate filter, 100 µm or finer Mandatory on every PD install; 100 µm for general lube, 40 µm for chemical-dosing service. Factory does not ship the strainer; size and order it on the same quote.
- Mount the rotor shaft horizontal regardless of pipe orientation Pipe can run horizontal or vertical; rotor shaft must be horizontal. Tilted rotors load bearings asymmetrically and drift K-factor off calibration.
- Throttle INLET, on-off OUTLET, open slowly Water-hammer is the most common cause of failure on heavy oil. Cracking a full-line valve open under viscous load bends the rotor shaft on the first cycle.
- Pre-spin the rotors on first fill; flush the new pipeline first Push the rotors several times by hand from the outlet flange before first pressurizing. On new builds, flush with a spool first to clear welding slag.
- Run continuous service at 50–80 % of rated max; add a bypass Continuous operation at rated max accelerates wear. Pulsating flow downstream of a reciprocating pump needs a gas-loaded accumulator upstream or goes to Coriolis.
Frequently asked questions
What does a high-viscosity oval gear flow meter measure, and how is it different from the standard build?+
A high-viscosity oval gear flow meter is a positive-displacement instrument built around a dedicated rotor with a high-viscosity tooth profile and tightened tip clearance, designed to meter liquids in the 200 to 2000 mPa·s range; lube oil, gear oil, resin, paint, polyol, molasses, chocolate liquor, polymer dosing solutions, and warmed heavy-fuel-oil service near room temperature. Two interlocking oval rotors in a precision crescent chamber meter four chamber-volumes per rotor revolution, and the rotation count converts to a pulse, a 4-20 mA signal, or a mechanical pointer totalizer. The flagship oval-gear build is rotor-optimized for 0.6 to 200 mPa·s; this high-viscosity build extends the window 10× on the viscous end with a different rotor geometry. Pick this build whenever the fluid sits above ~150 mPa·s.
Why not a turbine meter for high-viscosity service?+
Turbine meters are viscosity-limited to roughly 10 cSt at service (~9 mPa·s on a 0.9 g/cm³ oil). Above that limit, viscous drag damps the rotor wake, the K-factor drifts off the calibration curve, and accuracy collapses from ±0.5 % of rate down to several percent. The cleanest viscosity boundary on our site is 10 cSt; below it, the liquid turbine is the right pick on clean low-viscosity service with adequate straight-pipe; above it, oval gear positive displacement is the answer. Volumetric chamber displacement on the oval gear has no Reynolds-number dependence inside the design range, slip actually narrows as viscosity rises (the viscous film seals the rotor-clearance leakage path), and the error curve tightens at higher viscosity. Lube oil at 200-1000 mPa·s, gear oil and polyol at 1000-2000 mPa·s, and warmed HFO at 50-150 mPa·s all sit in the oval-gear high-viscosity rotor range where a turbine cannot operate.
What ships with the order, what is the cert, and what is the lead time?+
Lead time is 5 to 7 business days from the factory. Each unit ships with the dedicated high-viscosity rotor wet-calibrated against diesel oil on the factory loop per JJG 667-2010 (the China national metrological verification regulation for liquid volumetric flow meters), the K-factor stamped on the data plate, an ISO 9001 calibration certificate, and a mill cert traceable to heat number on the wetted-parts grade. Hazardous-area certification on the transmitter housing is CNEX Ex d IIB T4; the mechanical pointer build needs no Ex certification because it has no electronics. Ingress protection IP65 standard, IP66 by special order; EMC 2014/30/EU on the transmitter. Custody-transfer cert (API MPMS 5.2, OIML R 117, MID MI-005) and sanitary / pharma / FDA paper are buyer-arranged separately.
Need a meter for lube, resin, or warmed heavy oil?
Send pipe DN, viscosity, flow range, and working pressure. Engineering returns a sized quote; lead time 5–7 days.