1. Plunger Pump Basic Theory (1/11)
A reciprocating positive displacement pump is one in which a piston displaces a given volume at each stroke.
Example:
A cylindrical solid (e.g. piston) has displaced its volume from the large container to the small container. Volume B (displaced fluid) is equal to the piston volume A

2. Plunger Pump Basic Theory (2/11)
All reciprocating pumps have a fluid handling portion commonly called: Liquid end
That has displacing solid called: Plunger or piston
A container to hold the liquid called: Liquid cylinder
A suction valve to admit fluid from the suction pipe into the liquid cylinder.
A discharge check valve to admit flow from the liquid cylinder into the discharge pipe.
Packing to seal the joint between the plunger (piston) and the liquid cylinder preventing liquid leaking out of the cylinder and xxx from leaking into the cylinder

3. Plunger Pump Basic Theory (3/11)
Suction stroke
Plunger moved up
Pressure in cylinder reduced
When pressure becomes less than that in the suction pipe
Suction valves opens
Single acting pump
Liquid flows into cylinder and fills the volume being vacated by up works movement of the piston
Discharge valve is closed by high pressure in the discharge pipe

4. Plunger Pump Basic Theory (4/11)
Discharge stroke
Plunger moves down causes an increase in
Pressure of the liquid contained thein
Pressure becomes immediately higher than suction pressure
Causes to close suction valve
Single acting pump
Further plunger movement further rise of liquid pressure
When equal to that in discharge pipe discharge valves opens

5. Plunger Pump Basic Theory (5/11)
Discharge stroke
Liquid flows into discharge pipe
Volume =>equal to plunger displacement less small losses
Single acting pump

6. Plunger Pump Basic Theory (6/11)
Two suction and
two discharge valves
Double acting pump

7. Plunger Pump Basic Theory (7/11)
Liquid end
Crank - and throw device - Driven by motor electrical Diesel engine (Combuston engine)
Drive gear internal external

8. Plunger Pump Theory (8/11)
This type of pump is used when:
Dependability is of prime importance even when the pump is operated continuously for long periods an where the pressure is very high.
Cast liquid end plunger pumps are used for low and moderate pressure
Forged liquid end plunger pumps are used for high pressure

9. Plunger Pump Theory (9/11)
Liquid cylinder
Commonly made out of forged steel
Stuffing boxes and valves chambers
Are usually integral with the cylinder
Plunger
Are made by a number of materials. Plunger must be hard and smooth as possible to reduce friction and to resist wear by the plunger - packing.
Hardened chrome alloy steels and steel coated with hard metal alloy or ceramics are must commonly used.

10. Plunger Pump Theory (10/11)
Stuffing box
Vary widely depending upon service conditions - soft square packing - solid molded rings of square - V lip or U lip
Oil and grease can be integrated into a lantern between stuffing box ring to reduce friction and reduce packing and plunger wear.

11. Plunger Pump Theory (11/11)
Very feasible machine
Can operate at any point of pressure and flow within the limitations of the particular design.
The maximum speed of a particular design is primarily limited by the frequency with which the valves will open and close smoothly
The pump will operate against any pressure imposed upon it by the system it by the system it is serving.
Maximum pressure rating of a particular design is determinant by the strength of the liquid end.

12. Thank you for your attention !
Plunger Pump Theory
Thank you for your attention !