Lamborghini Veneno hypercar revealed

Lamborghini celebrated its 50th anniversary at the Geneva motor show with the Lamborghini Veneno, a 740bhp road-going racer based on the Aventador.
Lamborghini has said that all three units of the Veneno it will make have already sold for about €3 million (Rs 21.4 crore) each. The Geneva model is a Lamborghini prototype that it will continue to be tested on road and track.
The fundamental design is based on the Aventador, but there are several key changes to create what Lamborghini calls a “street-legal racing car”.
Its body, like the monocoque chassis, is fashioned entirely from carbon fibre-reinforced polymer. The bodywork is optimised for aerodynamic efficiency, creating downforce, reducing drag and cooling the 6.5-litre V12, which has had a 50bhp hike from its 690bhp state of tune in the Aventador.
The front end works as one large aerodynamic wing. The front wings are separated from the body, as on sports prototype racers.
The car’s underbody is smooth and channels air into a large diffuser, which houses four integrated exhaust pipes. Other features include an adjustable rear wing. The flared wheel arches house 20-inch alloy wheels at the front and 21-inch alloys at the rear.
The carbon fibre tub and aluminium subframes from the Aventador are carried over to the Veneno but adapted for its more extreme performance.
The engine benefits from enlarged air intakes, a higher rev limit and an exhaust system with a lower back pressure. The seven-speed automated manual gearbox, all-wheel drive system and pushrod suspension are also adapted from the Aventador.

THE TECHNOLOGY

The Veneno is further proof of Automobili Lamborghini’s unique competence in CFRP-based lightweight design. A monocoque made from carbon-fiber reinforced polymer forms the basis of the Veneno. It is largely similar to the Aventador monocoque – as are the aluminum sub-frames front and rear – although its form has been adapted to the new design. All exterior parts are made from CFRP. The Veneno meets all safety and registration requirements worldwide, and naturally also incorporates a full complement of safety systems from airbags through to the adapted ESP handling system.

Carbon fiber dominates the interior of the Veneno, too. The carbon fiber monocoque becomes visible inside the car in the area of the central tunnel and the sills. The two lightweight bucket seats are made from Lamborghini’s patented Forged Composite. The woven carbon-fiber CarbonSkin® is used to clad the entire cockpit, part of the seats and the headliner. This unique material is soaked in a very special kind of resin that stabilizes the fiber structure, while allowing the material to remain supple. Like a hi-tech fabric, this extremely fine-looking carbon-fiber matting fits perfectly to any form, and it reduces weight.

The racing personality has been transferred also to the instrument panel. It has been completely redesigned and now, thanks to an aggressive graphics and to the introduction of some additional features like the G-meter, provides all necessary information to the driver for control of the car.

The systematic, carbon-fiber, lightweight design of the Veneno is not only visible, it is also evident on the scales: With a dry weight of just 1,450 kilograms (3,190 pounds), the Veneno is even 125 kilos (275 pounds) lighter than the already extremely lean Aventador. The highly beneficial power-to-weight ratio of 1.93 kg/hp (4,25 lbs/hp) guarantees a performance that is nothing short of mind-blowing. Even the stunning acceleration figure of 2,8 seconds cannot adequately describe it. Despite an aerodynamic setup configured for extreme downforce, the Veneno possesses exceptionally low wind resistance which allows it to reach a top speed of 355 km/h (221 mph).

The twelve-cylinder with a displacement of 6.5 liters is a thrilling combination of absolute high-revving frenzy and phenomenal pulling power. Its output has been raised to 552 kW/750 hp, facilitated through enlarged intake paths, optimized thermodynamics, a slightly higher rated rpm and an exhaust system with even lower back pressure. The ISR manual gearbox, permanent all-wheel drive and pushrod suspension have all been specifically adjusted to meet the demands of the Veneno.

The Lamborghini Veneno celebrates its first public appearance at the 2013 Geneva Motor Show. The vehicle on show is the number 0, the Lamborghini test vehicle. Its future has not been determined yet, but it will allow Lamborghini to continue its activity of testing and innovation, both on the road and on the race track. The trilogy made of three unique vehicles will be produced in the course of the year 2013 and handed over to their future owners.

Origin of April Fools Day / why April 1 is considered as Fool's day

Precursors of April Fools' Day include the Roman festival of Hilaria, held March 25, and the Medieval Feast of Fools, held December 28, still a day on which pranks are played in Spanish-speaking countries.

In Chaucer's Canterbury Tales (1392), the "Nun's Priest's Tale" is set Syn March bigan thritty dayes and two. Modern scholars believe that there is a copying error in the extant manuscripts and that Chaucer actually wrote, Syn March was gon. Thus, the passage originally meant 32 days after April, i.e. May 2, the anniversary of the engagement of King Richard II of England to Anne of Bohemia, which took place in 1381. Readers apparently misunderstood this line to mean "March 32", i.e. April 1. In Chaucer's tale, the vain cock Chauntecleer is tricked by a fox.

In 1508, French poet Eloy d'Amerval referred to a poisson d’avril (April fool, literally "April fish"), a possible reference to the holiday. In 1539, Flemish poet Eduard de Dene wrote of a nobleman who sent his servants on foolish errands on April 1. In 1686, John Aubreyreferred to the holiday as "Fooles holy day", the first British reference. On April 1, 1698, several people were tricked into going to theTower of London to "see the Lions washed".

In the Middle Ages, up until the late 18th century, New Year's Day was celebrated on March 25 (Feast of the Annunciation) in most European towns. In some areas of France, New Year's was a week-long holiday ending on April 1. Many writers suggest that April Fools originated because those who celebrated on January 1 made fun of those who celebrated on other dates. The use of January 1 as New Year's Day was common in France by the mid-16th century, and this date was adopted officially in 1564 by theEdict of Roussillon.

A study in the 1950s, by folklorists Iona and Peter Opie, found that in the UK and those countries whose traditions derived from there, the joking ceased at midday. But this practice appears to have lapsed in more recent years.

Why do we Celebrate Holi?

Holi is celebrated after the full moon day in the month of phalgun (February – March). It is traditionally a harvest festival. Like all Hindu festivals, the reason for the celebration of Holi can be traced to Hindu scriptures and it commemorates the victory of good over evil. The significance of Holi is that victory of good over evil is achieved by a young devotee through his unshakable devotion for the Lord.

The date of Holi celebration depends on the moon and lunar calendar.

Holi Myth based on Prahlada and Demon Holika

Young Prahlada was an ardent devotee of Lord Vishnu but this was detested by his arrogant father, Hirnakashyipu, who was the king of the land. The father constantly sought for ways to eliminate his son and each time he failed miserably. But this only hardened his stance.

Now, the king had a sister named Holika who was immune to fire. So, she took young Prahlada and entered into fire. Legend has it that Prahlada came out of the fire without any burns but Holika was consumed by the fire. Huge bonfires that are burnt on the day prior to Holi symbolize this event from mythology.

Holi Legend based on Krishna and Radha

Holi is also associated with the evergreen love of Krishna and Radha.Krishna was jealous of Radha’s fair color and asked mother Yashoda for the reason for Radha’s fair color. Yashoda jokingly said if you are so jealous change her complexion by smearing color. Naughty young Krishnawas waiting for an idea for a prank and did exactly as his mother suggested.

For Krishna devotees, the festival is spread over two weeks. The most important events are held at Vrindavan, Mathura, Barsnar and Nandgaon.

Holi Myth based on Kamdev and Lord Shiva

Another important Holi legend is associated with Kamdev, the god of love. After the death of Sati, Lord Shiva took to severe meditation. Sati took rebirth as Parvati and tried to impress Lord Shiva. When her feminine charms failed, she took the help of Kamdev. Not knowing the seriousness of Lord Shiva’s meditation, Kamdev used his arrow of love on Shiva. The infuriated Shiva opened his third eye and turned Kamdev into ashes. This happened on the Holi day.

Holi Story based on Demon Dhundi

Another myth revolves around the demon Dhundi. She had received several boons through intense penance. Soon, she became arrogant and started killing children and eating them. But once Lord Shiva cursed her that she will be helpless before the pranks of young boys. One day a few boys in an intoxicated state took on her and started hurling abuses. The pranks of the boys increased as time went by and she could no longer tolerate it. Finally, she ran away from the area.

DIFFERENT TYPES OF FIBRES USED FOR FIBRE REINFORCED CONCRETE

DIFFERENT TYPES OF FIBRES USED FOR FRC

Fiber-reinforced concrete is concrete that uses other materials mixed in with the still liquid cement to reinforce the concrete structure. These fibers help make the concrete stronger and more resistant to temperature extremes. They also improve the concrete's water resistance. There are four types of fiber-reinforced concrete: steel fiber, glass fiber, synthetic fiber and natural fiber reinforced concrete.

1. Steel Fiber-Reinforced Concrete

Steel fiber-reinforced concrete is basically a cheaper and easier to use form of rebar reinforced concrete. Rebar reinforced concrete uses steel bars that are laid within the liquid cement, which requires a great deal of preparation work but make for a much stronger concrete. Steel fiber-reinforced concrete uses thin steel wires mixed in with the cement. This imparts the concrete with greater structural strength, reduces cracking and helps protect against extreme cold. Steel fiber is often used in conjunction with rebar or one of the other fiber types.

2. Glass Fiber Reinforced Concrete

Glass fiber-reinforced concrete uses fiberglass, much like you would find in fiberglass insulation, to reinforce the concrete. The glass fiber helps insulate the concrete in addition to making it stronger. Glass fiber also helps prevent the concrete from cracking over time due to mechanical or thermal stress. In addition, the glass fiber does not interfere with radio signals like the steel fiber reinforcement does.

3. Synthetic Fibers

Synthetic fiber-reinforced concrete uses plastic and nylon fibers to improve the concrete's strength. In addition, the synthetic fibers have a number of benefits over the other fibers. While they are not as strong as steel, they do help improve the cement pumpability by keeping it from sticking in the pipes. The synthetic fibers do not expand in heat or contract in the cold which helps prevent cracking. Finally, synthetic fibers help keep the concrete from spalling during impacts or fires.

4. Natural Fiber Reinforced Concrete

Historically, fiber-reinforced concrete has used natural fibers, such as hay or hair. While these fibers enhance the strength of concrete they can also make it weaker if too much is used. In addition, if the natural fibers are rotting while being mixed, then the rot can continue even while in the concrete. This eventually leads to the concrete crumbling from the inside which is why natural fibers are no longer used in construction.

ADVANTAGES OF FIBRES

Polypropylene and Nylon fibers:

• Improved mix cohesion and enhanced pumpability over long distances
• Improved freeze-thaw resistance
• Improved resistance to explosive spalling in case of a severe fire
• Improved impact resistance
• Increased resistance to plastic shrinkage during curing

Steel fibers:

• Improved structural strength
• Reduced steel reinforcement requirements
• Improved ductility
• Reduced crack widths and control of crack widths  thus improving durability
• Improved impact & abrasion resistance
• Improved freeze-thaw resistance

Blends of both steel and polymeric fibers are often used in construction projects in order to combine the benefits of both products; structural improvements provided by steel fibers and the resistance to explosive spalling and plastic shrinkage improvements provided by polymeric fibers.

In certain specific circumstances, steel fiber can entirely replace traditional steel reinforcement bar in reinforced concrete. This is most common in industrial flooring but also in some other precasting applications. Typically, these are corroborated with laboratory testing to confirm performance requirements are met. Care should be taken to ensure that local design code requirements are also met which may impose minimum quantities of steel reinforcement within the concrete. There are increasing numbers of tunnelling projects using precast lining segments reinforced only with steel fibers.

FIBRE REINFORCED CONCRETE

Fibre reinforced concrete (FRC) may be defined as a composite materials made with Portland cement, aggregate, and incorporating discrete discontinuous fibres. Plain unreinforced concrete is a brittle material, with a low tensile strength and a low strain capacity. The role of randomly distributes discontinuous fibres is to bridge across the cracks that develop provides some post-cracking ductility. If the fibres are sufficiently strong, sufficiently bonded to material, and permit the FRC to carry significant stresses over a relatively large strain capacity in the post-cracking stage.

There are other ways of increasing the strength of concrete. The real contribution of the fibres is to increase the toughness of the concrete (defined under the load vs. deflection curve), under any type of loading. That is, the fibres tend to increase the strain at peak load, and provide a great deal of energy absorption in post-peak portion of the load vs. deflection curve.

When the fibre reinforcement is in the form of short discrete fibres, they act effectively as rigid inclusions in the concrete matrix. Physically, they have thus the same order of magnitude as aggregate inclusions; steel fibre reinforcement cannot therefore be regarded as a direct replacement of longitudinal reinforcement in reinforced and prestressed structural members. However, because of the inherent material properties of fibre concrete, the presence of fibres in the body of the concrete or the provision of a tensile skin of fibre concrete can be expected to improve the resistance of conventionally reinforced structural members to cracking, deflection and other serviceability conditions.

The fibre reinforcement may be used in the form of three – dimensionally randomly distributed fibres throughout the structural member when the added advantages of the fibre to shear resistance and crack control can be further utilised . On the other hand, the fibre concrete may also be used as a tensile skin to cover the steel reinforcement when a more efficient two – dimensional orientation of the fibres could be obtained.

Related posts:

 DIFFERENT TYPES OF FIBRES USED FOR FRC

FLY ASH IN CONCRETE

APPLICATION OF FLY ASH IN CONCRETE

Over the past several decades, the use of fly ash in concrete has had a successful track record. The performance benefits fly ash provides to mechanical and durability properties of concrete have been thoroughly researched and documented in actual structures. Cement and Concrete Industry accounts for 50% fly ash utilization, the total utilization of which at present stands at 30 million tons (28%). The other areas of application are low lying area fill (17%), roads and embankments (15%), dyke raising (4%), brick manufacturing (2%) etc. The life cycle cost of fly ash based building materials/constructions is much lower taking into account the environmental benefits and durability aspects.

Fly ash concrete, as the two words suggest, is just an alternate version of concrete within which a predefined content of cement has been salvaged by instilling fly ash. The percentage of cement being replaced can vary, depending upon the use and priorities. Normally it gets in between 10-40%, whereas it may go up to 60% in High Volume Fly Ash Concrete. It is generally found that fly ash content in the cementitious material varies from 30-80% for low strength (20MPa) to high strength (100MPa). The amount of substitution is also dependent on the chemical composition of the fly ash and the Portland cement. The two properties of fly ash that are of most concern are the carbon content and fineness. Both of these properties will affect the air content and water demand of concrete.

MODIFICATION IN CONCRETE CHARACTERISTICS

Effects of fly ash, especially class F, on fresh and hardened concrete properties has been extensively studied by many researchers in different laboratories, including the U.S. Army Corps of Engineers, PCA and the Tennessee Valley Authority. Finer fly ash increases the water demand due to increase in surface area. The finer material requires more air-entraining agents to give the mix the desired air content. If fly ash is uniform in size, the mix design can be adjusted to give a good uniform mix.

Use of fly ash increases the absolute volume of cementitious compared to non-fly ash concrete; therefore the paste volume is increased, leading to a reduction in aggregate particle interference and enhancement in concrete workability. The spherical particle shape of fly ash also participates in improving workability of fly ash concrete because of the so-called “ball- bearing” effect. It has been found that both classes of fly ash concrete improve concrete workability.

Using fly ash in air-entrained and non-air entrained concrete usually reduces bleeding by providing greater fines volume and lower water content for a given workability. Concrete with relatively high fly ash content will require less water than non-fly ash concrete of equal slump.

All class F and most class C fly ashes increase the time of setting of concrete.

Strength of fly ash concrete is influenced by type of cement, quality of fly ash and curing temperature compared to that of non-fly ash concrete proportioned for equivalent 28-day compressive strength. Concrete containing typical class F fly ash may develop lower strength at 3 or 7 days of age when tested at room temperature. However, fly ash concrete usually has higher ultimate strengths when properly cured.

On the basis of a comparative experimental study of freeze-thaw durability of conventional and fly ash concrete, it has been observed that addition of fly ash has no major effect on the freeze-thaw resistance of concrete if the strength and air content are kept constant.

One of the most important reasons for using fly ash in highway construction is to inhibit the expansion resulting from Alkali-Silica Reaction. It has been found that the alkalies released by the cement preferentially combine with the reactive silica in the fly ash rather than in the aggregate and the alkalies are tied up in non-expansive calcium-alkali-silica gel.

FLY ASH CONCRETE – PROS AND CONS

The advantages of using fly ash far outweigh the disadvantages. The most important benefit is reduced permeability to water and aggressive chemicals. Properly cured concrete made with fly ash creates a denser product because the size of the pores is reduced. This increases strength and reduces permeability.

ADVANTAGES

Since fly ash particles are spherical and in the same size range as Portland cement, a reduction in the amount of water needed for mixing and placing concrete can be obtained. In pre-cast concrete, this can be translated into better workability, resulting in sharp and distinctive corner and edges with a better surface appearance. This also makes it easier to fill intricate shapes and patterns. Fly ash also benefits pre-cast concrete by reducing permeability, which is the leading cause of premature failure. The use of fly ash can result in better workability, permeability, cohesiveness, finish, ultimate strength and durability. The fine particles in fly ash help to reduce bleeding and segregation and improve pumpability and finishing, especially in lean mixes.

DISADVANTAGES

Poor quality fly ash can have a negative impact on concrete. It can actually increase the permeability of concrete. Some concrete will set slowly when fly ash is used. Freeze-thaw durability may not be acceptable with the use of fly ash in concrete. The amount of air entrained in the concrete depends on the amount of fly ash used and it controls the freeze-thaw durability. High carbon content in certain fly ash products absorbs some air entraining agents, reducing the amount of air produced in the concrete, making the concrete susceptible to frost damage. High carbon fly ash materials tend to use more water and darken the concrete as well. Most of the time, High-fineness and Low-carbon fly ash will result in high early strength. Some class C fly ash will not protect against the alkali-aggregate reaction. Lastly, it is important for the precast concrete producer to test the mix design continually, because fly ash is a group of materials that comes from burning coal.

Related posts:
Fibre reinforced Concrete

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Transparent Concrete/ Plastic optic fibre concrete pdf

Transparent Concrete/ Plastic optic fibre concrete pdf free download click here
downloads: 11238 till february 2013

Sample:

ABSTRACT

Energy saving and safety evaluation are two key issues for infrastructure. In this paper, the development of a novel smart transparent concrete using plastic optical fiber (POF) and Fiber Bragg Grating (FBG) is discussed, along with its transparent and smart sensing properties. The experimental results show that an optical fiber can be easily combined with concrete and that the POF could provide a steady light transmitting ratio. Moreover, the FBG can be used as a sensing element for strain and temperature. This paper also discusses the mechanical effects of introducing POF into concrete specimens. Because the smart transparent concrete can be regarded as a “green” energy saving construction material and as a smart intrinsic sensor for long-term Structural Health Monitoring (SHM), it is a promising technology for field applications in civil infrastructure.

Mtech admission 2013

Month (2013)	Institute
March	GITAM University, JPIIT, Tejpur University, Dr. Harisingh Gaur V.V., Ism Dhanbad, Upes, IIT Bombay, IIT Kanpur, IIT Roorkee, IIT Kharagpur, IIT Patna, IIT Gandhinagar, IIT Jodhpur, IIT Guwahati,NITIE,DA-IICT,IIT Mandi(MS), IIITDM Jabalpur, Jamia Millia Islamia, IIT Delhi
April	Amrita VV, SIT Pune, Jadhavpur University, Panjab University, ISIM, DIAT, IIT Patna, RGUKT, Besu Shibpur, LNM-IIT, DTU, BITS Pilani, IIT-Bhb, IITM Gwalior, NIRMA University, BIT Mesra, Bharti Vidyapeeth, NIFT, NITTR, VIT, VAST, Christ University, IIITD
May	Hindustan University, Vignan University, CUCET, IIST, Ghrec, Sbce, Jain University, MIT Pune, Graphic Era University, VJTI, PEC, DIT, CCMT(For NITS), DAVV, RGPV, Ansal University, SGSIT, PGEC, GNDU, University of Calcutta
June	SATI Vidisha, Coep, Vssit, acsir, Bvp Pune, Pgcet, Mriu, Wce, Mits, Scms, Ymca, JEC Jabalpur, Cetntral university of Punjab, CAM(RTU), Gujrat University, Nittr Bhopal, PTU,
July	KeralaUniversity, Goa College Of Engineering, CDLU, Galgotia, GEC Karad, UIET, University of pune, Gbtu
August	MBM Jodhpur,

RECIPROCATING PUMP

INTRODUCTION

As discussed in last chapter, pumps are hydraulic machines that convert mechnical energy to hydraulic energy, which is in the form of pressure energy. If the mechanical energy is converted into hydraulic energy by sucking the liquid into a cylinder in which a piston is reciprocating (moving backward and forward), the pump is called reciprocating pump. In this pump the reciprocating action exerts a thrust on the liquid and increases its pressure energy.

(Remember, in a centrifugal pump the convertion of energy is by centrifugal action whereas in a reciprocating pump it is by reciprocating action)

PARTS OF A RECIPROCATING PUMP

MAIN PARTS

1.     Suction pipe

Similar to that of a centrifugal pump. Receives water from the sump and transfers to the cylinder.

2.     A cylinder with a piston, piston rod, connecting rod and a crank

The cylinder is usually circular in cross section. The diameter of piston is same as that of the cylinder so that it fits inside the cylinder. The piston rod connects the rear end of the piston to the connecting rod. The piston rod always moves to and fro. The other end of connecting rod is attached to outer side of the crank. The crank is circular in shape and is rotated by an electric motor.

3.     Delivery pipe

It receives water from the cylinder and delivers it to the water at the upper tank or outlet.

4.     Suction valve

It is attached to the suction pipe. Similar to that in a centrifugal pump, it is a one way valve or non-return valve. It allows water to move upwards only. But unlike the centrifugal pump, it is not always open when the pump is working.

5.     Delivery valve

It is attached to the delivery pipe. It is also a one way valve or non-return valve.

working of a reciprocating pump

As said the centrifugal pump consists of a piston moving to and fro. The movement of piston is obtained by connecting the crank by means of a connecting rod.  The crank is rotated by an electric motor. When the crank is at A, the piston is at the extreme left position in the cylinder. As the crank rotates from A to C, it pulls the piston and the piston moves from left to right. The movement of piston from left to right creates a vaccum in the cylinder. The sump of water on which atmospheric pressure is acting is at a higher pressure than the pressure inside the cylinder. Thus the water is forced into the suction pipe and it opens the suction valve and enters the cylinder.

After the crank completes its 180^o, it moves back from C to A. Thus it pulls the piston from right to left. Thus due to increased pressure of water in the cylinder, it closses the suction valve and opens the delivery valve. Thus the water is pushed to the delivery pipe to the overhead tank.

Thus in every rotation of the crank, a cycle of suction of water and delivering it to the overhead tank takes place.

TYPES OF RECIPROCATING PUMP

Reciprocating pumps can be classified based on:

                   I.            According to water on one side or both side of piston

a.     Single-acting pump

This is the one discussed above.

b.     Double acting pump

In a double- acting pump the water is acting on both sides of the piston. Thus there are two suction pipes and two delivery pipes. When there is suction stroke on one side of the piston, there is delivery stroke on the other side. Thus for one revolution of crank there are 2 suction strokes and 2 delivery strokes. The main advantage of this type of pump is that the discharge and work done is almost twice as that of the single-acting pump.

                 II.            According to number of cylinders provided

a.     Single cylinder pump

b.     Double cylinder pump

c.      Triple cylinder pump

CENTRIFUGAL PUMPS

INTRODUCTION

Pumps are hydraulic machines that convert mechanical energy to hydraulic energy. The hydraulic energy is in form of pressure energy. Centrifugal pumps convert mechanical to pressure energy by centrifugal action.

PRINCIPLE

Centrifugal pumps work on the principle of forced vortex flow which means that when a certain mass of liquid is rotated in by an external torque, rise in pressure head of rotating liquid takes place. Rise in pressure head is directly proportional to the square of tangential velocity of the liquid at that point (pressure head directly proportional to square of velocity ie, it is directly proportional to square of radius). Thus at outlet of the impeller, where radius is more, the rise in pressure head will be more  and the liquid will be discharged at the outlet with a high pressure head. Due to this high pressure head, liquid will be lifted to a high level.

PARTS OF A CENTRIFUGAL PUMP

Main parts of a centrifugal pump:

1.    Impeller

It is the rotating part of the centrifugal pump. It consists of a series of backward curved vanes. Impeller is connected to a shaft which is connected to an electric motor.

2.    Vane

Vanes are backward curved blades connected to the impeller. It guides the water from the eye of impeller to the casing.

3.    Casing

It is an airtight passage surrounding the impeller. It is designed in such a way that water discharged at outlet of the impeller is converted into pressure energy. From the impeller the water moves to the delivery pipe.

Important types of casings:

·         Volute casing

It is a spiral type of casing in which area increases gradually. Increase in area decreases the velocity of flow. The decrease in velocity increases the pressure of water flowing through the casing.

The main disadvantage of volute casing is that, the efficiency of pump decreases as large amount of energy is lost due to the formation of eddies in the casing.

·         Vortex casing/whirlpool casings

In whirlpool casing, a circular chamber is introduced between the casing and impeller. This circular chamber considerably reduces the formation of eddies and thus reduces the loss of energy. Thus the efficiency of pump is increased.

4.    Suction pipe

It is a pipe which is connected to inlet of pump whose other end is dipped into water in the sump. At the bottom end a foot valve and a strainer is fitted. The foot valve is a non-return valve, ie it allows water to flow only in upward direction, which automatically closes when water flows backwards. The strainer prevents solid materials in water from entering the suction pipe.

5.    Delivery pipe

Pipe whose one end is connected to outlet of pump and other end delivers water at a required height. The delivery pipe collects the high pressure water coming out of the casing.

 PRIMING AND CAVITATION

PRIMING

Priming is the operation in which the suction pipe, casing of the pump and a portion of the delivery pipe is completely filled up from outside source with the liquid (usually water) to be raised by the pump before starting the pump. Thus from these parts the air is removed and is completely filled by the liquid.

Why priming is done?

When the pump is running in air, the head generated is much less compared to head generated when the pump is filled with water. In such case, water may not be sucked from the pump. The pump will be just rotating without rising the water to the required level. To avoid this priming is done.

CAVITATION

Cavitation is the phenomenon of formation of vapour bubbles of flowing liquid in the region where the pressure of the liquid falls below the vapour pressure, and the sudden collapsing of the these vapour bubbles in a region of higher pressure. When the bubble collapse a high pressure is generated. The metallic surface, above which these vapour bubbles collapse, is subjected to high pressure and can cause pitting action on the surface. Thus cavities are formed on the metallic surface and also considerable noise and vibrations are produced.