Introduction
• Topic: Internal Gear/Lobe Pump
• Name: Matthew Stoangi
• Objective:
To provide a clear understanding
of the mechanics involved within
an internal gear pump. As well as
to acknowledge it’s function as a
widely used oil pump design.
Internal Gear/Lobe Pump
4 Lobe in 5 Lobe Oil
Pump
Internal View
External
View
Internal Gear/Lobe Pump:
Defined
•Uses the meshing of gears to pump fluid
by displacement in hydraulic
applications.
•Gear pumps are fixed displacement
devices where a fixed amount of fluid is
pumped per single revolution
•Gear pumps are designed to operate in
both forward and reverse directions
•Can function as either a pump or a motor
3. Fluid Fills Void
2. Diverging
Gears
Create
Suction
1. Fluid
Enters
Through
Intake
Port
& Moves
Towards
Discharge Port
4.Converging
Gears Expel
Fluid
5. Fluid
Exits
Through
Discharge
Port
Gears In Constant Mesh – No Fluid
Travel At This Point
Image:
<http://en.wikipedia.org>
Operation Summary
• Gears separate on intake side of pump
• Suction pulls the fluid from intake port
to fill the void
• Fluid is carried through the housing by
the gears to the discharge port
• Fluid is expelled out the discharge port
by the mesh of the gears
• Tight mechanical tolerances combined
with constant rotation create the
effective seal necessary to prevent
reverse leakage and to promote overall
efficiency
Advantages Of Design:
• Total of two moving parts
• Non-pulsating constant and even
discharge
• Ideal for high-viscosity liquids
• Operates well in either direction
• Single adjustable gear clearance
• Relatively compact and efficient
design
Disadvantages Of Design:
• Requires moderate speeds to be
efficient
• Pressure limitations
• Single bearing accepts entire load
• Effective with high viscosity
fluids only
Applications
• Lubrication:
– Internal Combustion Engines
• Industrial:
– Moving/Transferring Fluids
• Circulation:
– High viscosity fluids
Intake Port
Discharge
Port
Photo Taken With Outer Gear
Removed To Expose Ports
Conclusion
In conclusion, upon dissection it
has been discovered that the
suction forces created by the
meshing gears are responsible for
the flow of the fluid through the
pump. This flow of fluid creates a
positive and non-pulsating
displacement which makes this
pump ideal for use in lubrication
applications.
References
• "Gear Pump." Wikipedia Encyclopedia.
Updated: September 7 2005 Accessed:
October 3 2005
<http://en.wikipedia.org>
• "Internal Gear Pumps." Pump School.
Created: 1998 Accessed: October 3
2005 <http://www.pumpschool.com/>
• "Centered Internal Gear Pump."
Integrated Publishing. Accessed:
October 3 2005
<http://www.tpub.com/>