Oval Gear Meters - 1/8" to 3/8" Threaded FLOMEC®

Meter Type
Positive Displacement (PD) Flow Meter designed to measure the flow of most fluids including high and varying viscosities without requiring recalibration.
How It Works
Positive Displacement Flow Meters measure the volumetric flow of fluids in pipes. As fluid flows through the chamber the oval gears rotate. Each rotation corresponds with a fixed volume of fluid that is picked up by a sensor creating a pulse signal. Electronic displays convert the pulse signal to a flow rate or totals.
Standard Features

  • High accuracy and repeatability, direct volumetric reading
  • No calibration required
  • Measures low and high viscosity liquids up to 1,000cps
  • Pressure rated up to 5800 PSIG
  • No straight pipe runs required up or downstream
  • Stainless Steel or Aluminum bodies
  • Bi-directional flow measurement
  • Factory Calibration Certificate supplied with each meter
  • 1 Year Limited Warranty

Optional Features

  • Measures up to 1,000,000cps (high viscosity rotors)
  • Quadrature pulse output option for high resolution
  • PF option for metering pulsating flows

LCD Display Features

  • Rate of Flow, 2 Totals (1 Resettable Batch, 1 Cumulative)
  • User Configurable to GPM, LPM or any Unit of Measure
  • Factory Calibrated for 1.0 Specific Gravity
  • Field Calibratable for fluids greater than 1.0 Specific Gravity
  • Digital Display with 6 Digits Starting at 0.01 (floating decimal)
  • Totals Maximum of 99,999,999
  • Powered by 3.6V Battery (approximate 3 Year life, for display only) or may be externally powered

Electronic Options

  • Local or Remote LCD (see below features)
  • Pulse Output (Open Collector NPN)
  • 4-20mA Outputs
  • Scaled Pulse Output
  • Alarms or Batch Controlling


Connection Sizes
1/8" (OM004)1/4" (OM006)1/4" (OM008)3/8" (OM008)
FLOW RANGES:*0.13 - 9.5 GPH (0.50- 36 LPH)0.5 - 27 GPH (2- 100 LPH)4 - 145 GPH (15- 550 LPH)4 - 145 GPH (15- 550 LPH)
ACCURACY (Of Reading @ 3cps -1000cps):
Standard± 1.0%± 1.0%± 1.0%± 1.0%
With RT14 Display w/ non-linearity correction± 0.2%± 0.2%± 0.2%± 0.2%
REPEATABILITY (Typical)± 0.03%± 0.03%± 0.03%± 0.03%
Aluminum Meter (A)220 PSIG (15 Bar)220 PSIG (15 Bar)-220 PSIG (15 Bar)
Stainless Steel Meter (S)495 PSIG (34 Bar)495 PSIG (34 Bar)-495 PSIG (34 Bar)
Stainless Steel Meter - Intermediate Pressure (N)1450 PSIG (100 Bar)1450 PSIG (100 Bar)-1450 PSIG (100 Bar)
Stainless Steel Meter - High Pressure (H)5800 PSIG (400 Bar)5800 PSIG (400 Bar)5800 PSIG (400 Bar)-
Meters with Pulse Out Only-4 to 250°F (-20 to 120°C)-4 to 250°F (-20 to 120°C)-4 to 250°F (-20 to 120°C)-4 to 250°F (-20 to 120°C)
Meters with LCD Display & Pulse Out Only14 to 140°F (-10 to 60°C)14 to 140°F (-10 to 60°C)14 to 140°F (-10 to 60°C)14 to 140°F (-10 to 60°C)
Meters with LCD Display & 4-20mA Output32 to 140°F (0 to 60°C)32 to 140°F (0 to 60°C)32 to 140°F (0 to 60°C)32 to 140°F (0 to 60°C)
For Lower Temperature RatingsContact UsContact UsContact UsContact Us
Standard Unit Ranges3 - 1,000 cps3 - 1,000 cps3 - 1,000 cps3 - 1,000 cps
Low Viscosities below 3cpsContact UsContact UsContact UsContact Us
High Viscosity Ranges---1,000 - 1,000,000 cps
PRESSURE DROP (At Full Std Capacity)Contact UsContact UsContact UsContact Us
RECOMMENDED STRAINER SIZE200 Mesh (75 Microns)200 Mesh (75 Microns)200 Mesh (75 Microns)200 Mesh (75 Microns)
OUTPUT PULSE RESOLUTIONPulses per Gallon (Pulses per Liter) - nominal
Reed Switch10600 PPG (2800 PPL)3975 PPG (1050 PPL)1345 PPG (355 PPL)1345 PPG (355 PPL)
Hall Effect10600 PPG (2800 PPL)3975 PPG (1050 PPL)2690 PPG (710 PPL)2690 PPG (710 PPL)
QP-Quadrature Hall Option10600 PPG (2800 PPL)3975 PPG (1050 PPL)2690 PPG (710 PPL)2690 PPG (710 PPL)
PF-Pulsating Flow (Hall Effect)10600 PPG (2800 PPL)3975 PPG (1050 PPL)675 PPG (178 PPL)675 PPG (178 PPL)
HR-High Resolution Hall Effect42400 PPG (11200 PPL)15900 PPG (4200 PPL)N/AN/A
Reed Switch Output30VDC x 200mA max. [Maximum Thermal Shock 50°F (10°C)/minute]
Hall Effect Output (NPN)3-Wire Open Collector, 5-24VDC Max. 20mA Max.
Optional Outputs4-20mA, Scaled Pulse, Quadrature Pulse, Flow Alarms or Two-Stage Batch Control
PROTECTION CLASSIP66/67 (NEMA4X), Optional Exd I / IIB T4/T6, Integral Ancillaries can be supplied I.S. (intrinsically Safe)
Body - Aluminum Meter (A)AluminumAluminumAluminumAluminum
Body - Stainless Steel Meters (S, N)316L Stainless Steel316L Stainless Steel316L Stainless Steel316L Stainless Steel
Body - Stainless Steel Meter (H)316 Stainless Steel316 Stainless Steel316 Stainless Steel316 Stainless Steel
Bearings - Aluminum Meter (A)Carbon CeramicCarbon Ceramicnonenone
Bearings - Stainless Steel Meters (S, N, H)Carbon CeramicCarbon CeramicCarbon CeramicCarbon Ceramic
Shaft - Aluminum & Stainless Steel BodiesStainless SteelStainless SteelStainless SteelStainless Steel
Rotor - Aluminum Meter (A)316 Stainless Steel316 Stainless SteelPPSPPS
Rotor - Stainless Steel Meters (S, N, H)316 Stainless Steel316 Stainless Steel316 Stainless Steel316 Stainless Steel
Seals - Aluminum Meter (A)FKM (Viton™)FKM (Viton™)FKM (Viton™)FKM (Viton™)
Seals - Stainless Steel Meters (S, N, H)PTFE encapsulated FKMPTFE encapsulated FKMPTFE encapsulated FKMPTFE encapsulated FKM
CONN. TO CONN. LENGTH2.91" (74mm)2.91" (74mm)2.91" (74mm)2.91" (74mm)
*Maximum flow is to be reduced as viscosity increases, see flow de-rating guide. Maximum recommended pressure drop is 14.5 PSIG (1 bar)



  • PTFE encapsulated FKM (Viton™) Seals
  • Buna-N (Nitrile) Seals (-40°F minimum)
  • Up to 300°F rated
  • BSPP (G) Female Connections
  • Bottom Entry Manifold Mounts (SS Body only)
  • N.I.S.T. Certification

Replacement Parts

  • Please contact our Sales Dept.

Alternate Meters

  • (none)

Application Notes

  • Saturated Steam Service: Not acceptable
  • Potable Water: Not acceptable.
  • Vacuum Service: Not acceptable
  • Gaseous Service: Not acceptable
  • General Non-Suitable Services: Fluids with unfiltered solids. Note that deionized (DI) and ultra-pure waters require all stainless steel components and PTFE seals.
  • Installation: Limit display’s exposure to sun.
  • Corrosion: Before ordering, verify all materials of our flow meters are compatible with the service media(s), intermittently used cleaners, the environment, and cleaning processes in conjunction with the temperatures and pressures of the application(s) and future applications. John C. Ernst Co. does not make chemical compatibility recommendations. Compatibility is the responsibility of the user and/or specifying party.

Model Number Matrix
Model Number Matrix