Precise flow with high-viscosity fluids
Because the volume of the gear pockets is fixed, flow rate varies far less than with centrifugal pumps even as pressure changes.
Product group · Flow Transfer Products
Gear Pumps
Gear pumps are positive-displacement pumps that carry fluid volumetrically as a pair of interlocking gears rotates. For high-viscosity fluids (oil, resin, honey-like products), they give a precise, constant flow rate that is relatively independent of pressure; supplied in external-gear and internal-gear types, with cast iron or stainless casing options.
Flow rate0.1 – 50 m³/h
Pressure1 – 25 bar
ViscosityHigh (oil/resin)
CasingCast iron / stainless
Why it matters
What does a gear pump do?
It provides steady, precise flow with high-viscosity fluids where a centrifugal pump falls short.
Pulse-free, constant flow
Fluid moves continuously and smoothly between the gear pockets, giving a stable flow profile on dosing and process lines.
High-temperature-resistant types are available
With special gasket and material options for hot-oil and thermal-process lines, it runs safely at high temperature.
Simple design, low maintenance cost
Its simple mechanical design, with few moving parts, keeps maintenance needs and spare-parts cost low.
Types
Sub-types of gear pumps
All three carry the fluid in gear pockets; what sets them apart is the gear arrangement and temperature resistance.
External-gear pump
Two gears mesh from outside each other; with its simple, economical design, it is the most widely used type for oil transfer and hydraulic power units.
- Economical and widely used
- Medium-to-high viscosity
- Oil and hydraulic systems
Internal-gear pump
One gear rotates inside the other; it runs more quietly and, with low pulsation, is preferred for precise dosing and process transfer.
- Quiet, with low pulsation
- Precise flow control
- Process and dosing lines
Hot-fluid (thermal oil) gear pump
With special gasket and material options, suited to transferring high-temperature fluids such as thermal oil and asphalt.
- High-temperature resistance
- Suited to thermal-oil lines
- Special gasket options
Selection criteria
What data determines the right gear pump?
Without the first two points, selection cannot be made. The rest determine the material and gasket type.
ParameterWhy it mattersWhat we need from you
Flow rate
Calculated from the line's demand and the gear pump's rotation speed.
m³/h
Pressure
Determined by line resistance and valve losses.
bar
Viscosity
The fluid's consistency determines pump size and rotation speed.
cSt / cP
Operating temperature
Directly affects the choice of gasket and material.
°C
Fluid corrosiveness/solids content
If solid particles are present, tolerance and material hardness matter.
Clean / particle-laden
Connection size
Flanged or threaded connection size and mounting location.
DN size
For a quote, having the following is enough
It's fine if you don't have all of it. We'll fill in the gaps together with you.
Create a quote request- Flow rate and pressure
- The fluid's viscosity and temperature
- Solid particle content or corrosiveness
- Whether external-gear or internal-gear is preferred
- Connection size
- The existing pump's nameplate data (if it's a replacement)
FAQ
Questions from the field
The questions we hear most often when quoting gear pumps.
Why is a gear pump preferred for viscous fluids?
Thanks to its positive-displacement design, flow rate varies far less than with centrifugal pumps even as the fluid's viscosity rises; this gives consistent flow with thick products like oil and resin.
Can it be used with fluids containing solid particles?
To a limited extent. Because of the tight tolerances between the gears, clean or very fine-particle fluids are recommended; for coarser particle content, a lobe or mono pump is more suitable.
What is the temperature limit?
Up to about 120°C with standard gaskets; with special gasket and material selection, it can run at higher temperatures (hot oil, asphalt).
What about maintenance and spare-parts supply?
Thanks to its simple mechanical design, gear sets and seals are supplied as standard spare parts; maintenance intervals vary with how corrosive the fluid is.
Do you only serve Istanbul?
No. While our office is on Istanbul's Anatolian side (Ataşehir), we supply and ship across Istanbul's European side, the surrounding provinces and the Marmara region, and Turkey as a whole — covering your equipment end to end, from a single source.
Next step
Let's clarify your requirement together
Share the fluid's viscosity and your flow-rate requirement, and let's determine together the right gear pump for your line.
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