1. How chemical pumps work
Discovering what a gear pump is
They are in short, positive displacement pumps pumping fluid by using gears. The gears
come in and out of mesh, creating a pumping non-pulsating action.
Gear pumps are able to pump at high pressures and excel at pumping high viscosity liquids
efficiently.
Delving into the workings of a gear pump?
If we take a look at the intake side of a gear pump we’ll see the gears becoming unmeshed.
This unmeshing produces a suction action which in turn forces the fluid into the volume
pockets.
The fluid is then transported to the discharge side of the pump.
Fluid is trapped with an external gear pump. The liquid is transported to the pump’s
discharge side which can be found between the interior pump casing and gear teeth. For an
internal pump the fluid is trapped and carried between the external and internal gears teeth to
the discharge side.
The meshing of gears on the discharge side of the pump forces the fluid out under pressure.
Gear pumps, what types are there?
There are basically two types of gear pumps – internal and external. They actually share
much in common. Firstly they both have an idler gear which is driven by the driving gear.
Secondly, they also work by gears coming in and out mesh. This creates the pumping action.
The difference between the two types is relatively simple. It’s to do with the placement of the
gears and where the liquid is trapped.
The internal gear pump has an external gear with a smaller internal gear inside of it. Since
the internal gear is smaller when the gears come out of mesh on the intake side it creates

2. pockets, between the external and internal gears’ teeth, which is where the fluid is
transported.
Internal gear pumps are ideal for pumping high viscosity fluids, but pumping large solids can
damage the pump. Internal gear pumps are ideal for pumping high viscosity fluids. The
downside of them is that they pumping large solids damages the pump.
Rotating against each other are external gears which are identical. It’s these which create the
pump action. The fluid travels from the intake to the discharge side of the pump between the
gears’ teeth and pump casing. External gear pumps used more for application that call for
high pressure.
Michael Smith Engineers are experienced in chemical pumps