2. • A piston pump is a type of reciprocating pump that moves and
pressurizes fluid by using one or more reciprocating pistons; it is
typically driven by an electric motor through a crankshaft and
connecting rod.
• Though there are many types, all piston pumps feature at least one
piston moving in an enclosed cylinder. The piston will normally have
one or more O-rings on its periphery, which seals against the cylinder
as the piston moves. The piston draws liquid into the cylinder and
pushes it out under pressure as the volume in the cylinder gets
progressively larger and then smaller as the piston reciprocates.
3.
4. Swash Plate
• The amount of fluid pumped is dictated by the swash plate angle/pitch.
Changing the pitch of the swash plate, changes the stroke of each
piston, which changes the amount of fluid drawn into each cylinder,
and consequently the amount of fluid pumped. Moving the swash plate
to a neutral pitch will result in no fluid being pumped (because the
length of each piston stroke is effectively zero). It is possible to
reverse the direction of the fluid being pumped by changing the angle
of the swash plate.
5. Cylinder Block
• The cylinder block consists of a round cylinder with smaller bored
cylinders penetrating through its entire length. Each of the smaller
bored cylinders provides the necessary space for the pistons to move
linearly back and forth (reciprocating motion). As the pistons move,
they charge and discharge the cylinder space. The cylinder volume
charged and discharged per stroke depends upon the length of each
piston’s stroke.
6. Port Plate
• Fluid is drawn into the cylinders, and discharged from the cylinders,
via the port plate (sometimes called the ‘valve plate’).
Inlet/Outlet
• Fluid enters or exits the pump through this port. The swash plate
dictates in which direction the fluid will flow through the pump i.e. if
the port is an inlet or outlet port.
Drive Shaft
• The power to rotate the pump is provided via the drive shaft. Piston
pumps are usually electrically or mechanically driven, although it is
also possible to hydraulically operate the pump.
7. Positive Displacement Pump
Positive displacement pumps are self priming pumps and are normally
used as priming devices.
• They consist of one or more chamber, depending upon the
construction, and the chambers are alternatively filled and emptied.
• The positive displacement pumps are normally used where the
discharge rate is small to medium.
• They are popularly used where the viscosity of the fluid is high.
• They are generally used to produce high pressure in the pumping
system.
8. Dynamic Pressure or Roto-Dynamic Pump
• In dynamic pressure pump, during pumping action, tangential force is
imparted which accelerates the fluid normally by rotation of impeller.
• Some systems which contain dynamic pump may require positive
displacement pump for priming.
• They are normally used for moderate to high discharge rate.
• The pressure differential range for this type of pumps is in a range of
low to moderate.
• They are popularly used in a system where low viscosity fluids are
used.
12. • With an enormous, wide pressure range, piston pumps are able to reach
incredibly high pressures that can be controlled without any impact on
the rate of flow. They’re incredibly clever pieces of kit, and have many
uses and advantages.
• As well as the above, they also have a continuous rate of discharge
meaning they can move viscous fluids, high gas volumes and even
solids throughout machinery. So a major advantage of a piston pump is
efficiency, as well as how useful they are and how they can move
fluids through a machine, regardless of viscosity.
13. • If they’re properly maintained, it also means they have a long
performance life and will serve you well throughout.
• Piston pumps are vital for many businesses and are an incredible feat
of engineering, having been used for a long period of time within
certain industries. The major benefit of them is therefore how useful
they are to operations, often proving vital when used.
15. • Cost is a major disadvantage of a piston pump, as they can be
expensive affairs up-front. They pay for themselves in the long-run,
but the initial cost may seem a little eye-watering due to the size and
complexity of the machinery.
• Another major disadvantage comes down to maintenance yet again, as
if not properly lubricated, the mechanical parts within a piston pump
are prone to wear due to the high pressure they are placed under and
the psi they generate.
16. • They are also incredibly heavy due to the nature of the components
used, and are also very large. Valves must be kept intact with piston
pumps, and must be resistant to abrasives for larger, thicker liquids or
solids to pass through.
• This leads us back to the issue of maintenance and lubrication being of
vital importance. Such complex pieces of engineering require great
filtering accuracy and regular maintenance to ensure the unit remains
fully operational at all times, so it’s hugely important they are well-
lubricated and maintained throughout their lives.
