Pumps How do they work

07/04/2023 Visit us on : www.psadhesive.com 1

Pumps

Applications in

IndustryAdhesive Tape PaperFlexible packing


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.


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.


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 agitationForces to cause motion increase proportionately as speed increaseFluid 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 Pumps4 Handling Adhesives


Positive Displacement PumpA 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.


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.


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 variationsexternal 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



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 ChambersCompressed air flows in or out of the air Chambers.The pump has a right and left air chambers.

Fluid HousingsThe 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 Valvethe 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 valvesA 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.


Mufflerthe muffler minimizes the noise of the exhaust air. different mufflers provide different levels of noise reduction.

Wetted partsthe 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 lifeo Air power offers convenience for many installations , no

electrical hazard o Excellent portabilityo Handles a wide variety of fluid viscosities, abrasive, and

corrosive qualitieso Seal less , leak proof design prevents fluid waste , mess and

hazardo 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 applicationsThe fluid to air ratio relationship is 1 : 1 , meaning100psi of compressed air , theoretically will deliver 100 psi of fluid outputAir 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.


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).


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 end2. double end3. single rotor4. 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 systemsMost 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 turndownManual 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.


And Now

Let’s watch some Animations / Video Clips

onthe Actual workingOf variety of Pumps


Or copy this url and pastehttp://upload.wikimedia.org/wikipedia/commons/9/95/Peristaltic_pump.gif

Please Watch this AnimationTo understand the principle of operation

Peristaltic pump

http://upload.wikimedia.org/wikipedia/commons/9/95/Peristaltic_pump.gif




http://en.wikipedia.org/wiki/File:Peristaltic_pump.gif


Screw Pump


Plunger Pump


Mechanism of a scroll pump

http://en.wikipedia.org/wiki/Scroll_pump


360 Degree Peristaltic Pump




Internal Gear Pump Animation

Visit : http://www.youtube.com/watch?v=omJ4IM6i1DM

http://www.youtube.com/watch?v=omJ4IM6i1DM

http://www.youtube.com/watch?v=omJ4IM6i1DM


Vane Pump Animation

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

http://www.youtube.com/watch?v=BnvzPoNSXCg

http://www.youtube.com/watch?v=BnvzPoNSXCg


SRU Rotary Lobe Pump

Visit : http://www.youtube.com/watch?v=m-ZWPnvC0wc

http://www.youtube.com/watch?v=m-ZWPnvC0wc




variable displacement piston pump

Visit:http://www.youtube.com/watch?v=2mh902AP7Yw

http://www.youtube.com/watch?v=2mh902AP7Yw




hydraulic gear pump

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

http://www.youtube.com/watch?v=HPBaCRK_t78


piston pump

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

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


Double Diaphragm pump

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

http://www.youtube.com/watch?v=RuEFZGDbL2M


Double Diaphragm PumpAnother variety

Visit:http://www.youtube.com/watch?v=0V35Laueboc

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.


Thank

You

Technology

Pumps How do they work