This document classifies and describes different types of centrifugal pumps. It discusses closed and open impellers based on whether vanes are enclosed or exposed. It also describes volute, diffuser, and vortex pumps based on their casing design. Volute pumps gradually increase area to reduce velocity and increase pressure. Diffuser pumps use fixed vanes to gradually convert velocity to pressure. Vortex pumps add a circular chamber between the impeller and volute to further convert kinetic to pressure energy.

1. CLASSIFICATION
of Centrifugal Pump
Prof. P.W.Ingle
Sanjivani College Of Engineering
Kopargaon

2. CLASSIFICATION
Based on mechanical construction
Closed: Shrouds or sidewall enclosing the
vanes.
Open: No shrouds or wall to enclose the
vanes.
Semi-open or vortex type.

3. Closed Impeller
• The vanes are provided with metal cover
plates or shrouds ( to hide) on both the
sides.
• It provides better guidence for the liquid
and has a high efficiency.
• It is employed when the liquid to be
pumped is pure and relatively free from
debris.

4. Closed Impeller

5. Closed Impeller

6. • Vanes are open on both sides.
• Open face impellers are popular because
the cost less money to manufacture so the
pump cost less.
• Such impellers are employed for pumping
liquids which contains suspended solid
matter like sewage, paper pulp, water
containing sand or grit i.e. small particles
of stone and sand.
Open impeller

7. Open and Semi Open Impeller

8. Open impeller

9. Open impeller

10. Close and Open Impeller

11. Semi-open Impeller
• The semi open impeller, due to its lack of
a front shroud, also tends to create greater
unbalanced axial force than does the
closed impeller.
• This impellers can be used even if the
liquid contains some debris .

12. Semi-open Impeller

14. Centrifugal Pumps Groups
• Centrifugal pumps can be classified in
three major groups depending on their
design and application:
1. Volute pumps
2. Diffuser pumps OR casing with guide
blades
3. vortex pumps

15. Volute pumps

16. • In this type of casing or pump the area of flow
gradually increase from the impeller outlet to
delivery pipe so as to reduce the velocity of flow.
• Thus the increase in pressure occurs in volute
casing in other words the kinetic energy is
converted into the pressure energy.
• The volute pump is the most common type of
radial-flow centrifugal pump. It has an impeller
housed in a progressively widening spiral casing
as shown

18. • Water enters the eye of the impeller and is
thrown radial outward.
• Volute pumps can be single-suction or
double-suction pumps.
• in a single-suction pump impeller water is
admitted on one side of impeller.
• In a double-suction pump, water is fed from
both sides of the impeller, significantly
improving its hydraulic balance. As a result,
double-suction volute pumps can produce
higher pressures than single-suction pump

19. • Volute pumps are commercially available as
single-stage (single impeller) or multistage
(multiple impellers) pumps.
• The most common reason for the multi-stage
configuration is to increase the head produced by
the pump.
• If a multi-stage pump has single suction impellers,
the impellers are usually arranged with equal
numbers discharging in opposite directions to
counteract the hydraulic imbalance on each of the
impellers.
• Volute pumps are used where irrigation water is
obtained from depths generally less than 20 feet,
The exact value of possible lift is determined by
the net positive suction head required by the
pump.

20. Diffuser pumps or casing with
diffuser(guide) ring

21. • In a diffuser-type centrifugal pump, the impeller is
surrounded by a ring of fixed diffuser vanes that
provide enlarging passages in which the velocity
of the water leaving the impeller is reduced and
as a result pressure is increased.
• The diffuser vanes provide a more controlled flow
and allow for a more efficient conversion of
velocity into pressure than volute pumps since
the change from velocity to pressure takes place
gradually.
• Diffuser pumps, especially large ones, often have
efficiencies over 90 percent.
• Diffuser pumps have the additional advantage of
a balanced radial loading on the impeller, which
reduces the chance of shaft failure due to fatigue.

22. Centrifugal pump diffuser

23. VORTEX CASING
• If a circular chamber is provided between the
impeller and the volute chamber, the casing is
known as vortex casing.
• The circular chamber is known as vortex or
whirlpool chamber and such a pump is known as
volute pump with vortex chamber
• The vortex chamber converts some of the kinetic
energy into the pressure energy.
• Volute chamber further increases the pressure
energy thus more efficient than volute pump.