Pumps How do they work

Pumps
Adhesive Tape
Paper
Flexible packing
7/2/2013 1Visit us on : www.psadhesive.com

Handling Adhesives is always
a Challenge
The main issues are
 The Viscosity ?
 The Stickiness ?
 The solvent ? Organic ? or Water ?
 The distance the adhesive needs to be moved ?
 To deliver the adhesive right to the coating
end straight from the source
 Cleaning ?

A pump is a device
that moves liquids or slurries,
by mechanical action.
Pumps can be classified into three major groups
direct lift,
displacement,
and gravity pumps.
A variety of Pumps are Used to meet this
Challenge

Pumps
operate by some mechanism
and
consume energy
to perform mechanical work of moving the
Adhesive.
Pumps operate via many energy sources,
including manual operation,
electricity, engines, or Air pressure.

Pumps
can be classified into
positive displacement pumps,
impulse pumps,
velocity pumps,
gravity pumps,
steam pumps
and
valve less pumps.

Pumps
also classified as
positive displacement pumps,
impulse pumps,
velocity pumps,
gravity pumps,
steam pumps
and
valve less pumps.

1. How do pumps work ?
Pumps move fluid in a variety of ways
Centrifugal Pumps
Use centrifugal force to push the fluid through the outlet.
Metering Pumps
Bellows, diaphragm, peristaltic, piston, and syringe pumps
are all metering pumps that pull the fluid through the inlet
valve into a chamber, close the inlet valve, and then push
the fluid through the outlet valve.7/2/2013 7Visit us on : www.psadhesive.com

Positive Displacement Pumps
Bellows, double-diaphragm, flexible impeller, gear,
oscillating, piston, progressing cavity, rotary lobe, rotary
vane, and peristaltic pumps have a fixed cavity that the
fluid is pushed through by rollers, gears, or impeller. As
the fluid is pushed through, it leaves a void or vacuum
which pulls in more fluid.

2. Are centrifugal pumps variable speed ?
Most centrifugal pumps do not have variable speed
motors. However, you can control flow rate on the
discharge using a valve.
3. What exactly is a positive displacement pump ?
A positive displacement pump emits a given volume of
fluid for each revolution of the motor. Bellows, double-
diaphragm, flexible impeller, gear, oscillating, piston,
progressing cavity, rotary lobe, rotary vane, and
peristaltic pumps are all positive displacement pumps.

4. Which pumps can I run dry ?
Peristaltic, piston pumps with ceramic heads, bellows
pumps, and diaphragm pumps can be run dry for any
length of time. Centrifugal, rotary vane, and gear pumps
should not be run dry; exceptions are if the gear or
impeller is made of a self-lubricating material such as
RYTON in which case the pump can be run for a few
minutes while priming.
5. What is the maximum viscosity rating for pumps ?
This depends on the type of pump and the specific pump.
Diaphragm pumps (especially double diaphragm pumps)
and gear pumps are usually the best for viscous fluids.7/2/2013 10Visit us on : www.psadhesive.com

6. What pumps do you carry that will handle
particulates ?
Diaphragm pumps, bellows pumps and peristaltic pumps
will work well. When choosing materials, consider
chemical compatibility and resistance to wear.
Use a pump with larger fittings so they don't clog as
easily.

7. I need gentle pumping action, what do you
recommend ?
A peristaltic pump, used at low speeds. You can also use a
diaphragm pump, again at low speed. Centrifugal and
gear pumps, which work at high speeds and have high
shear rates, should be avoided.

8. When do you need to perform maintenance on
pumps ?
This depends on the pump and the application. In general,
diaphragms on metering pumps last about 6 to 12 months;
gears on gear pumps last about 3 to 6 months; and motors
usually last for years.
DC motors require periodic brush replacement. It is
important to monitor brush wear; normally brushes should
be replaced every 6 months.

To select a Best Pump
to handle viscous fluids , it’s important
to understand viscous fluid behavior at
different shear rates.
There are a number of types of viscous
fluid behavior.

Newtonian fluids
Viscosity is constant with
change in shear rate or
agitation
Forces to cause motion
increase proportionately as
speed increase
Fluid showing Newtonian
behavior include water,
mineral oils, syrup, hydro
carbons and resins

Thixotropic Fluids
Viscosity decreases as shear
rate or agitation increases.
The force to cause motion
are relatively lower as speed
increases. Examples are
soaps, tars, vegetable oils,
glue, inks , and some
slurries.

Dilatant fluids
Viscosity increase as shear
increases. Forces to cause
motion may greatly increase as
speed increases , examples are
slurries, clay etc.

Plastic and pseudo
plastic Fluids
Viscosity decreases as shear
rate increases , but initial
viscosity may not be great
enough to prevent start of flow
in a typical pumping system.
Typical plastic fluids are gels,
latex , lotions

Bellows
These pumps move fluid
through a reciprocating
bellows cavity that is coupled
to a driving rod. Pumps are
found in the "Metering" and
"Positive Displacement" pump
sections.

Centrifugal
A rotating vanned disk
attached to a drive shaft
moves fluid without
pulsation as it spins.
The outlet can be restricted
without damaging the
pump.

Diaphragm
Pulsations of one or two
flexible diaphragms
displace liquid while
check valves control the
direction of the fluid flow.

Flexible Liner
The outer surface of an inert
liner and inner surface of a
rotating body block create a
fluid channel used to gently
pump fluids without
pulsation.

Flexible Impeller
Elastomeric impeller traps
fluid between the impeller
blades and a moulded
housing that sweeps fluid
through the pump housing.

Gear
Fluid is trapped between
the teeth of two or three
rotating gears.
Gear pumps are good for
high system-pressure
applications and are
often magnetically
driven

Hand
Manually powered pumps
of various designs used for
short term or repetitive
liquid transfer applications.
Hand-operated,
reciprocating, positive
displacement,

Peristaltic
(tubing)
Fluid only contacts the
tubing—rollers of a motor-
driven pump head push the
fluid along the tubing as
they rotate.
Non contaminating and easy
to clean.

Peristaltic tube pump with two
sprung rollers

A Peristaltic pump
is a type of positive displacement pump used for
pumping a variety of fluids.
The fluid is contained within a flexible tube fitted
inside a circular pump casing (though linear peristaltic
pumps have been made).
A rotor with a number of "rollers", "shoes", "wipers",
or "lobes" attached to the external circumference of the
rotor compresses the flexible tube.

As the rotor turns, the part of the tube under
compression is pinched closed (or "occludes") thus
forcing the fluid to be pumped to move through the
tube.
Additionally, as the tube opens to its natural state after
the passing of the cam ("restitution" or "resilience")
fluid flow is induced to the pump. This process is
called peristalsis

Peristaltic pumps
are typically used to pump clean/sterile or aggressive fluids
because cross contamination with exposed pump components
cannot occur.
Some common applications include pumping IV fluids through an
infusion device, aggressive chemicals, high solids slurries and
other materials where isolation of the product from the
environment, and the environment from the product, are critical.
It is also used in heart-lung machines to circulate blood during
a bypass surgery as the pump does not cause
significant haemolysis.
Peristaltic pumps are also used in a wide variety of industrial
applications. Their unique design makes them especially suited to
pumping abrasives and viscous fluids.

Piston
Rotating pistons of
varying stroke lengths
pump fluids through
check valves.
Good for high-pressure
applications.

Piston Pumps
2 Ball Piston pumps
These Pumps feature two balls
checks that control fluid flow.
They are typically used with low
to medium viscosity fluids up to
100,000 centipoise ( cPs ) with
fluid delivery up to 18.1 gpm
( 68.6 lpm ) , depending on the
application

Piston
Pumps
4
Handling
Adhesives

Positive Displacement
Pump
A positive displacement pump makes a fluid move by
trapping a fixed amount and forcing (displacing) that
trapped volume into the discharge pipe.
Some positive displacement pumps use an expanding
cavity on the suction side and a decreasing cavity on
the discharge side.
Liquid flows into the pump as the cavity on the suction
side expands and the liquid flows out of the discharge
as the cavity collapses.
The volume is constant through each cycle of
operation.7/2/2013 34Visit us on : www.psadhesive.com

Lobe Pumps
are used in a variety of
industries including
Pulp and paper,
chemical,
food

How lobe pumps work
Lobe pumps are similar to external gear pumps in
operation in that fluid flows around the interior of the
casing.
Unlike external gear pumps, however, the lobes do not
make contact. Lobe contact is prevented by external
timing gears located in the gearbox.
Pump shaft support bearings are located in the gearbox,
and since the bearings are out of the pumped liquid,
pressure is limited by bearing location and shaft
deflection.7/2/2013 36Visit us on : www.psadhesive.com

How lobe pumps work
1. As the lobes come out of mesh, they create
expanding volume on the inlet side of the pump.
Liquid flows into the cavity and is trapped by the
lobes as they rotate.
2. Liquid travels around the interior of the casing in
the pockets between the lobes and the casing—it does
not pass between the lobes.
3. Finally, the meshing of the lobes forces liquid
through the outlet port under pressure.

Gear pump
A gear pump uses the meshing of gears to pump fluid
by displacement. They are one of the most common
types of pumps for hydraulic fluid power applications.
Gear pumps are also widely used in chemical
installations to pump fluid with a certain viscosity.
There are two main variations
external gear pumps which use two external spur gears,
and
internal gear pumps which use an external and an
internal spur gear.

Gear pumps are positive
displacement
(or fixed displacement),
meaning they pump a
constant amount of fluid for
each revolution.
Some gear pumps are
designed to function as either
a motor or a pump.

External gear pump design for
hydraulic power applications.
Internal gear pump design for
automotive oil pumps.
Internal gear pump design for high
viscosity fluids.

Generally used in
 Petrochemicals Pure or filled bitumen,
pitch, diesel oil, crude oil, lube oil etc.
 Chemicals Sodium silicate, acids,
plastics, mixed chemicals, iso cyanates
etc.
 Paint and ink.
 Resins and adhesives.

Gear pump
This is the simplest of rotary positive displacement
pumps. It consists of two meshed gears that rotate in a
closely fitted casing.
The tooth spaces trap fluid and force it around the outer
periphery.
The fluid does not travel back on the meshed part,
because the teeth mesh closely in the centre. Gear
pumps see wide use in car engine oil pumps and in
various hydraulic power packs.

Screw pump
A Screw pump is a more complicated type of rotary
pump that uses two or three screws with opposing
thread—e.g., one screw turns clockwise and the other
counter clockwise. The screws are mounted on parallel
shafts that have gears that mesh so the shafts turn
together and everything stays in place. The screws turn
on the shafts and drive fluid through the pump. As with
other forms of rotary pumps, the clearance between
moving parts and the pump's casing is minimal.

Widely used for pumping difficult materials, such as
sewage sludge contaminated with large particles, this
pump consists of a helical rotor, about ten times as long
as its width. This can be visualized as a central core of
diameter x with, typically, a curved spiral wound
around of thickness half x, though in reality it is
manufactured in single casting.

This shaft fits inside a heavy duty
rubber sleeve, of wall thickness also
typically x. As the shaft rotates, the
rotor gradually forces fluid up the
rubber sleeve. Such pumps can
develop very high pressure at low
volumes.

Plunger pumps
are reciprocating positive
displacement pumps.
These consist of a cylinder with a
reciprocating plunger. The suction
and discharge valves are mounted
in the head of the cylinder. In the
suction stroke the plunger retracts
and the suction valves open
causing suction of fluid into the
cylinder. In the forward stroke the
plunger pushes the liquid out of
the discharge valve. Efficiency and
common problems

With only one cylinder in
plunger pumps, the fluid flow
varies between maximum flow
when the plunger moves
through the middle positions,
and zero flow when the
plunger is at the end positions.
A lot of energy is wasted when
the fluid is accelerated in the
piping system. Vibration
and water hammer may be a
serious problem. In general the
problems are compensated for
by using two or more cylinders
not working in phase with each
other.

Double Diaphragm
Pump

Double Diaphragm Pump
A more common type of diaphragm
pump is the air-operated double
diaphragm pump.
It uses pressurized air to activate the
diaphragms instead of a mechanical
device.
This is basically two pumps in one –
one is on the suction cycle,
while the other is on the discharge
cycle.
The air valves alternately pressurize the
inside of one diaphragm chamber and
exhaust air from the other one.

Inside the Double
Diaphragm Pump

Air Chambers
Compressed air flows in or out of the air Chambers.
The pump has a right and left air chambers.
Fluid Housings
The fluid being pumped flows through the fluid housings.
Each pump has a right and left fluid Housing
Diaphragms
Diaphragms separate the air chambers and fluid housings
in the pump. The diaphragm is a material that flex with
increasing or decreasing air pressure. A common shaft
connects the two diaphragms.

Inlet manifold
Fluid flows from the fluid container through the inlet
manifold either to the right or left fluid housing.
Outlet manifold
Fluid flows out of the right or left fluid housing past the
check valves , then through the outlet manifold.

Air Valve
the air valve directs compressed air either the right or
left air chamber. the air valve consists of a
triggering mechanism , a valve cup, and a valve plate.
The air valve directs compressed air through a port to
one of the air chambers while the opposite air chamber
is directed to the exhaust port
Check valves
A double diaphragm has four fluid check valves , two
inlet check valves and two outlet checks valves.
the check valves control the fluid flow through the fluid
housing and manifolds of the pumps.
Most double diaphragm pumps use ball type check
valves. housing , and outlet manifold.

Muffler
the muffler minimizes the noise of the exhaust air.
different mufflers provide different levels of noise
reduction.
Wetted parts
the wetted parts include all parts that come into contact
with the pumped fluid.
they include the inlet manifold , ball checks and seats ,
diaphragms , fluid housing , and outlet manifold.

Advantages
o High fluid delivery rates at low fluid application pressure ,
less than 120 psi ( 8.5 bar )
o Easy to install on a cover , pail , wall
o Many diaphragm options for fluid versatility with extended
pump life
o Air power offers convenience for many installations , no
electrical hazard
o Excellent portability
o Handles a wide variety of fluid viscosities, abrasive, and
corrosive qualities
o Seal less , leak proof design prevents fluid waste , mess and
hazard
o Can run dry without damage

Air Valve advantages
 The air valve is the principle feature that differentiates this
pump from the others
 Not dependent on the air being clean, dry or containing oil
 Allows for easy online maintenance of the pump. Decreased
repair time and cost
 Uses fewer seals compared to other designs.
 Operates on very little air pressure , 15 psi ( 1 bar ) or less
 Creates a more gentle pumping action during high flow rates

Limitations
Not suitable for high pressure applications
The fluid to air ratio relationship is 1 : 1 , meaning
100psi of compressed air , theoretically will deliver 100 psi
of fluid output
Air consumption in a continuous duty operation may result in
higher energy consumption than other pumps

Gear Pumps
Gear pumps (with external teeth) (fixed displacement) are simple
and economical pumps. The swept volume or displacement of
gear pumps for hydraulics will be between about 1 cm3 (0.001
litre) and 200 cm3 (0.2 litre).
They have the lowest volumetric efficiency ( ) of all three basic
pump types (gear, vane and piston pumps) These pumps create
pressure through the meshing of the gear teeth, which forces fluid
around the gears to pressurize the outlet side.
For lubrication, the gear pump uses a small amount of oil from
the pressurized side of the gears, bleeds this through the
(typically) hydrodynamic bearings, and vents the same oil either
to the low pressure side of the gears, or through a dedicated drain
port on the pump housing.7/2/2013 64Visit us on : www.psadhesive.com

Some gear pumps can be quite noisy, compared to other types,
but modern gear pumps are highly reliable and much quieter than
older models. This is in part due to designs incorporating split
gears, helical gear teeth and higher precision/quality tooth
profiles that mesh and un mesh more smoothly, reducing pressure
ripple and related detrimental problems.
Another positive attribute of the gear pump, is that catastrophic
breakdown is a lot less common than in most other types of
hydraulic pumps. This is because the gears gradually wear down
the housing and/or main bushings, reducing the volumetric
efficiency of the pump gradually until it is all but useless. This
often happens long before wear causes the unit to seize or break
down.

Rotary vane pumps
Rotary vane pumps (fixed and simple adjustable displacement)
have higher efficiencies than gear pumps, but are also used for
mid pressures up to 180 bars in general.
Modern units can exceed 300 bars in continuous operation,
although vane pumps are not regarded as "high pressure"
components. Some types of vane pumps can change the centre of
the vane body, so that a simple adjustable pump is obtained.
These adjustable vane pumps are in general constant pressure or
constant power pumps:

the displacement is increased until the required pressure or power
is reached and subsequently the displacement or swept volume is
decreased until an equilibrium is reached.
A critical element in vane pump design is how the vanes are
pushed into contact with the pump housing, and how the vane tips
are machined at this very point.
Several type of "lip" designs are used, and the main objective is to
provide a tight seal between the inside of the housing and the
vane, and at the same time to minimize wear and metal-to-metal
contact.
Forcing the vane out of the rotating centre and towards the pump
housing is accomplished using spring-loaded vanes, or more
traditionally, vanes loaded hydro dynamically (via the pressurized
system fluid).7/2/2013 67Visit us on : www.psadhesive.com

Screw pumps
Screw pumps (fixed displacement) consist of two Archimedes'
screws that intermesh and are enclosed within the same chamber.
These pumps are used for high flows at relatively low pressure
(max 100 bar). They were used on board ships where a constant
pressure hydraulic system extended through the whole ship,
especially to control ball valves but also to help drive the steering
gear and other systems.
The advantage of the screw pumps is the low sound level of these
pumps; however, the efficiency is not high.
The major problem of screw pumps is that the hydraulic reaction
force is transmitted in a direction that's axially opposed to the
direction of the flow.

There are two ways to overcome this problem:
(1) put a thrust bearing beneath each rotor;
(2) create a hydraulic balance by directing a hydraulic force to a
piston under the rotor.
Types of screw pumps:
1. single end
2. double end
3. single rotor
4. multi rotor timed
5. multi rotor untimed.

Types of screw pumps:
(1) single end
(2) double end
(3) single rotor
(4) multi rotor timed
(5) multi rotor untimed.

Bent axis pumps
Bent axis pumps, axial piston pumps and motors using the bent
axis principle, fixed or adjustable displacement, exists in two
different basic designs.
These have the best efficiency of all pumps.
Although in general the largest displacements are approximately
one litre per revolution, if necessary a two-litre swept volume
pump can be built.
Often variable-displacement pumps are used, so that the oil flow
can be adjusted carefully.
These pumps can in general work with a working pressure of up
to 350–420 bars in continuous work.

Axial piston pumps swash plate principle
Axial piston pumps using the swash plate principle (fixed and
adjustable displacement) have a quality that is almost the same as
the bent axis model.
They have the advantage of being more compact in design.
The pumps are easier and more economical to manufacture; the
disadvantage is that they are more sensitive to oil contamination.

Radial piston pumps
Radial piston pumps are used especially for high pressure and
relatively small flows. Pressures of up to 650 bar are normal. In
fact variable displacement is possible. The pump is designed in
such a way that the plungers are connected to a floating ring.
This floating ring can be moved horizontally by a control lever
& thus causes an eccentricity in the centre of rotation of the
plungers. The amount of eccentricity can be controlled to vary
the discharge. The suction & discharge can be totally reversed
seamlessly by shifting the eccentricity to the opposite side.
Hence both quantity & direction can be varied in a radial piston
pump, just as in the Swash plate pump.

Peristaltic pumps
Peristaltic pumps are not generally used for high pressures.
Pumps for open and closed systems
Most pumps are working in open systems. The pump draws oil
from a reservoir at atmospheric pressure.
It is very important that there is no cavitation at the suction side of
the pump. For this reason the connection of the suction side of the
pump is larger in diameter than the connection of the pressure
side.
In case of the use of multi-pump assemblies, the suction
connection of the pump is often combined. It is preferred to have
free flow to the pump (pressure at inlet of pump at least 0.8 bars).

The body of the pump is often in open connection with the
suction side of the pump.
In case of a closed system, both sides of the pump can be at high
pressure. The reservoir is often pressurized with 6-20 bars boost
pressure.
For closed loop systems, normally axial piston pumps are used.
Because both sides are pressurized, the body of the pump needs a
separate leakage connection.

Multi pump assembly
In a hydraulic installation, one pump can serve several cylinders
and motors. However, in that case a constant pressure system is
required and the system always needs full power.
It is more economic to give each cylinder and motor its own
pump. In that case, multi-pump assemblies can be used. Gear
pumps are often supplied as multi-pumps.
The different chambers (sometimes of different sizes) are
mounted in one body or built together. Vane pumps and gerotor
pumps too are often available as multi-pumps.

600 series mid-flow peristaltic
pumps
Watson-Marlow are world leaders in the fastest
growing pump type for industry, so we set
tough targets for the 600 series: increase
pressure and flow, cut maintenance time to less
than one minute and protect the process. 620
models are powerful, easy-to-operate pumps
offering industrial strength with unrivalled
precision.
Flow rates up to 4.8 gpm (18 litre/min)
Pressures up to 60 psi (4 bar)
0.1 rpm to 265 rpm with speed accuracy to 0.1
rpm:
2,650:1 turndown
Manual control; remote analogue digital and
network control; RS485 or RS232Intuitive,
easy-to-use membrane keypad with large keys.
60% fewer tube occlusions than our competitors
for unbeatable tube life.

Let’s watch some Animations /
Video Clips
on
the Actual working
Of variety of
Pumps

Or copy this url and paste
http://upload.wikimedia.org/wikipedia/comm
ons/9/95/Peristaltic_pump.gif
Please Watch this Animation
To understand the principle of operation
Peristaltic
pump

Screw Pump

Plunger Pump

Mechanism of a scroll pump

360 Degree Peristaltic
Pump

Double
Diaphragm
Pump

Internal Gear Pump Animation
Visit :
http://www.youtube.com/watch?v=omJ4IM6i1DM

Vane Pump Animation
Visit :
http://www.youtube.com/watch?v=BnvzPoNSXCg

SRU Rotary Lobe Pump
Visit :
http://www.youtube.com/watch?v=m-ZWPnvC0wc

variable displacement piston pump
Visit:
http://www.youtube.com/watch?v=2mh902AP7Yw

hydraulic gear pump
Visit:
http://www.youtube.com/watch?v=HPBaCRK_t78

piston pump
Visit:
http://www.youtube.com/watch?v=gcgWJatUnmc

Double Diaphragm pump
Visit:
http://www.youtube.com/watch?v=RuEFZGDbL2M

Double Diaphragm Pump
Another variety
Visit:
http://www.youtube.com/watch?v=0V35Laueboc

http://www.youtube.com/watch?v=Y6To-bgL4GE
Here is a Video link
to see how the Double
Diaphragm Pump Operates.

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