Flow Meters – Low Flow

Fixed Orifice, 0-4 to 0-40 GPH, 1.5-5 SCFM

  • Large, easy-to-read dial
  • High line pressure design
  • Rugged design
  • Vertical or horizontal mounting

Specifications: Flow Meter- Low Flow


Flow Range

Max Line Pressure

Max Line Temperature


Electrical Availability

Instructions & Drawings

2021 FG/FGS/FS

GPH 0-2 to 0-40
GPM 0-0.04 to 0-0.8
LPH 0-8 to 0-150
LPM 0-0.14 to 0-2.5
SCFH 0-300 to 0-480
SCFM 0-5 to 0-8
SLPM 0-140 to 0-225
Nm3/hr 0-8 to 0-14

3000 psig
(200 bar)

200°F (93°C)

Liquids 2%
Air 5%

1 or 2 Switches
No Enclosure

View Model Page →

F=Flow G=Gauge S=Switch

*Turndown results in 1st mark at approximately 30% full scale

Fixed-Orifice Flow Meters

Our flow meters are designed for those applications where a rotameter is not appropriate. Consider the inherent problems of rotameters – they are difficult to read, especially with dirty or opaque fluids, have low pressure ratings and allow vertical orientation only. Orange Research low flow flow meter models have large dials with bold markings and characters that are easy to read from a distance, handle high line pressures and can be mounted in any orientation.

Like rotameters, our flow meters are mounted directly in the flow stream, but with bodies machined from solid blocks of metal, they handle high-pressure applications of up to 3000 psi (vs 150 psi for rotameters). This makes flow meters a natural choice for hydraulic and pneumatic systems.

These fixed-orifice flow meter models are designed for low flow applications. We use a fixed Delrin orifice centered on a Buna-N diaphragm (Viton is optional), which provides sensitive responses to changes in flow. The rate is displayed on an easy-to-read dial face.

We offer these low flow flow meters with stainless steel bodies (and wetted parts). A variety of dial sizes are also available, from 2.5 inch to 4.5 inch. Choose from a wide selection of standard options; enough to satisfy any requirement.


Flow Meter – Low Flow – Switches and Relays

A variety of reed switches and relays can accompany our flow meters, or the meter can be supplied on its own, without a dial. SPST switches are offered normally open (N.O.) or normally closed (N.C.). SPDT reed switches are also available. DPDT relays are offered for high inductance applications, such as those incorporating motors or solenoids. More information on switches and relays.


Liquid Flow Meters

For liquids, our low flow flow meters are calibrated to customer-specified specific gravity and viscosity of the fluid to be measured (up to 150 CS). Otherwise, standard calibration is on water at 70° F. For oil service, flow meters are calibrated using oil (specific gravity 0.86 CS at 74° F). Special calibration is available to meet customers’ specific gravity and viscosity requirements using selected fluids and a conversion procedure. Standard calibration is for horizontal mounting; vertical is offered at no charge.


Air & Gas Flow Meters

For air and gas applications, our low flow flow meters are calibrated on air at 100 psig at 70° F. For non-standard fluids or conditions, a conversion procedure is required. Because gas is compressible, please supply pressure and temperature conditions and type of gas when the order is placed so that the density of the gas can be taken into account and noted on the dial face.


WARNING: This product contains Nickel, a chemical known to the State of California to cause cancer. For more information go to: www.p65warnings.ca.gov

2021 Family

2021 Front

2021 Back

WARNING: Some of our products contain Nickel, a chemical known to the State of California to cause cancer. For more information go to: www.p65warnings.ca.gov

Skip to content