Positive Displacement Meter
The BS1750 Positive Displacement Flow Meter measures low flow rates across fluids with a wide range of viscosities. Sur-Flo Meters & Controls supplies aluminum and stainless steel configurations for lubricants, fuels, chemicals, solvents, oils, and greases, with flow ranges from 0.003 to 120 gallons per minute depending on the selected model.
Meter type: Gear-based positive displacement flow meter
Ideal for: Low flow rates and fluids across a wide viscosity range
Flow range: 0.003 to 120 GPM, depending on model
Accuracy: ±0.5 percent of reading under specified flow and viscosity conditions
Pressure rating: Up to 5,000 psi
Housing: 6061-T6 aluminum or 303 stainless steel
The Sur-Flo BS1750 Positive Displacement Flow Meter
The Sur-Flo BS1750 directly measures fluid movement using two internal gears, making it suitable for low-flow applications and fluids that vary in viscosity. Available configurations provide different bore sizes, flow ranges, housing materials, seals, and sensor outputs. Certain models offer turndown ratios up to 400:1, while appropriate electronics support bidirectional measurement without requiring additional straight-run piping.
How the Positive Displacement Flow Meter Works
Fluid entering the meter rotates two internal gears. A non-intrusive sensor detects each gear tooth passing the sensor face and produces a sine-wave pulse. The pulse frequency corresponds to the actual flow rate, allowing connected electronics to calculate rate or total flow. Each meter receives a unique K-factor during factory calibration based on the number of pulses produced per unit of fluid volume.
Selecting the Right BS1750 Meter Configuration
Selecting a BS1750 requires the fluid type, viscosity, minimum and maximum flow rates, temperature, pressure, connection size, seal compatibility, and required output signal. Aluminum housings operate from -20°F to 185°F, while stainless steel housings extend the upper limit to 400°F. Teflon seals are standard, Viton seals are optional, and sensor options include magnetic, Hall-effect, preamplified, Quad-4, and 4–20 mA configurations for specified meter sizes.
Viscosity also affects the usable measuring range. The K-factor remains highly linear across the published range for liquids above 100 centipoise. Lower-viscosity liquids are more susceptible to fluid slip around the moving components. For fluids below 30 centipoise, published linearity applies across a 10:1 turndown measured from the maximum flow rate.
Sur-Flo also supplies an Industrial Oval Gear Meter for low-flow and high-viscosity applications. The correct meter depends on the complete operating conditions rather than fluid type alone.
BS1750 Positive Displacement Meter Applications
The BS1750 is suited to industrial liquid measurement where low flow, fluid viscosity, limited straight-pipe space, or high operating pressure affects meter selection. Material and seal compatibility must be confirmed for the specific liquid before ordering.
- Lubricants
- Fuels
- Chemicals and solvents
- Oils and greases
- Low-flow liquid measurement
- High-viscosity fluid service
- Bidirectional measurement with appropriate electronics
- Installations without additional straight-run piping
BS1750 Positive Displacement Flow Meter Specifications
Parameter | Details |
Model | BS1750 |
Measurement technology | Gear-based positive displacement |
Overall flow range | 0.003 to 120 GPM, depending on model |
Bore sizes | 1/4, 1/2, 3/4, and 1-1/4 inches |
Maximum pressure | 5,000 psi (345 bar) |
Accuracy | ±0.5% under published flow and viscosity conditions |
Repeatability | ±0.1% |
Aluminum temperature range | -20°F to 185°F (-29°C to 85°C) |
Stainless steel temperature range | -20°F to 400°F (-29°C to 204°C) |
Housing material | 6061-T6 aluminum or 303 stainless steel |
Bearings | Stainless steel |
Seal material | Teflon standard; Viton optional |
Calibration | Oil, NIST traceable |
Straight-run requirement | No additional straight-run piping required |
Flow direction | Bidirectional with appropriate electronics |
Sensor | Optional; selection depends on meter model |
Detailed model flow ranges, K-factors, dimensions, pressure-drop charts, part numbers, and sensor compatibility are available in the BS1750 Product Data Sheet.
Why Operations Choose the BS1750 Positive Displacement Meter
- Measures flow rates as low as 0.003 GPM
- Handles fluids across a wide viscosity range
- Provides accuracy of ±0.5 percent under specified conditions
- Delivers repeatability of ±0.1 percent
- Operates at pressures up to 5,000 psi
- Requires no additional straight-run piping
- Offers aluminum and stainless steel housings
- Supports Teflon and optional Viton seals
- Provides several sensor and output options
- Supports bidirectional measurement with appropriate electronics
Supplied by Sur-Flo Meters & Controls
Sur-Flo Meters & Controls supplies the BS1750 Positive Displacement Flow Meter from Calgary, Alberta, to industrial operations across Western Canada and beyond. Our team works with engineering, operations, and procurement personnel to confirm the required flow range, viscosity, materials, temperature rating, pressure rating, connections, seals, and signal output.
Frequently Asked Questions
What is the BS1750 Positive Displacement Flow Meter used for? The BS1750 measures low flow rates across fluids with a wide range of viscosities. Applications include lubricants, fuels, chemicals, solvents, oils, and greases.
How does the BS1750 measure flow? Fluid rotates two internal gears. A non-intrusive sensor detects the movement of the gear teeth and generates pulses proportional to the actual flow rate.
How accurate is the BS1750? The meter provides accuracy of ±0.5 percent under its published flow and viscosity conditions, with repeatability of ±0.1 percent.
What flow rates does the BS1750 support? Available configurations cover flow rates from 0.003 to 120 GPM. The exact range depends on the selected model.
Does viscosity affect the meter’s measuring range? Yes. Fluids below 100 centipoise are more susceptible to fluid slip. For fluids below 30 centipoise, published linearity applies across a 10:1 turndown from the maximum flow rate.
Does the BS1750 require straight-run piping? No. The meter does not require additional upstream or downstream straight-run piping.
Is the BS1750 bidirectional? Yes, when paired with appropriate electronics. The required electronics and sensor should be confirmed during model selection.
Should I choose an aluminum or stainless steel housing? Aluminum configurations are rated up to 185°F, while stainless steel configurations are rated up to 400°F. Fluid compatibility and operating temperature determine the appropriate material. For industrial processes, a stainless steel housing is recommended.