Force Mode Pumps Used In Bangladesh

FORCE MODE PUMPS USED IN BANGLADESH

PUMPS, WELLS AND HYDRAULIC MACHINERY | AIE 406

B.SC. AGRICULTURAL ENGINEERING

HAJEE MOHAMMAD DANESH SCIENCE AND TECHNOLOGY UNIVERSITY

PRESENTER

Md. ImranuzzamanID: 1007058

Level-4 Semester-IB.Sc. Agricultural Engineering

VERTICAL TURBINE PUMPA vertical turbine pump is a vertical axis centrifugal or mixed flow type pump comprising of stages which accommodate rotating impellers and stationary bowls possessing guide vanes.

These pumps are used where the pumping water level is below the limits of volute centrifugal pump.

CONSTRUCTIONIt has three main parts:

1. Pump Element:

The pump element is made up of one or more bowls or stages. Each bowl consists of an impeller and diffuser.

2. Discharge Column:

It connects the bowl assembly and pump head and conducts water from former to later.

3. Discharge head:

It consists of base from which the discharge column, bowl assembly and shaft assembly are suspended.

COMPONENTSMajor Components are: Motor Bowls Impellers Line shaft Column pipe

APPLICATION

Water and irrigation supply Cooling water circulation in conventional and

renewable power stations Booster service Offshore fire and service water Secondary recovery supply and injection

systems Mine dewatering

CLASSIFICATION OF VERTICAL TURBINE PUMP

1. Water Lubricated

2. Oil Lubricated

ADVANTAGES OF VERTICAL TURBINE PUMP

Generates high head and high discharge pressure Better handling of gas-liquid mixtures Flow rate less variable with pressure change No priming is required Pump can be powered by an AC electric motor or IC engine Can be used where the water surface is below the practical

limits

DISADVANTAGES OF VERTICAL TURBINE PUMP

The initial and maintenance costs are higher than a centrifugal pump

No easy way to adjust performance Complications in the installation, checking and

maintenance of this pump Impeller requires regular adjustment to preserve high

efficiency

SUBMERSIBLE PUMP

The submersible pump is a type of construction in which a tightly sealed driving motor is coupled directly to the turbine bowl assembly and is designed to be submerged in the fluid pumped.

Power is supplied to the motor by a highly insulated waterproof electrical cable running from the motor to the power source.

CONSTRUCTION

Pump element:

It consists of propelling shaft, usually made of stainless steel and bronze impellers. Water enters the pump through a screen located between motor and the pump.

Electric Motor:

The motor is enclosed in steel case filled with light oil of high dielectric strength. A mercury seal placed directly above the armature prevents oil leakage or water entrance at point

where the drive shaft passes through the case to the impellers.

COMPONENTS

Major components are: Motor Impeller Discharge pipe Pump shaft Cable

WORKING PRINCIPLE

A submersible pump pushes water to the surface by converting rotary energy into kinetic energy into pressure energy. This is done by the water being pulled into the pump: first in the intake, where the rotation of the impeller pushes the water through the diffuser. Produced liquids, after being subjected to great centrifugal forces caused by the high rotational speed of the impeller, lose their kinetic energy in the diffuser where a conversion of kinetic to pressure energy takes place. From there it goes to the surface. This makes the pump move the liquid to greater distances as compared to other forms of pumping.

APPLICATIONS

Submersible pumps are found in many applications. Single stage pumps are used for drainage, sewage pumping,

general industrial pumping and slurry pumping. They are also popular with pond filters.

Multiple stage submersible pumps are typically lowered down a borehole and used for residential, commercial, municipal and industrial water extraction, water wells and in oil wells.

Other uses for submersible pumps include sewage treatment plants, seawater handling, fire fighting, water well and deep well drilling, offshore drilling rigs, artificial lifts, mine dewatering, and irrigation systems.

ADVANTAGES OF SUBMERSIBLE PUMP It prevents pump cavitation It never has to be primed because it is already submerged in the fluid It eliminates the long vertical shaft from the ground surface to the

pump which reduces bearing friction and provides an unobstructed pipe for delivery of water to the surface

It can be used where the installation is flooded or where an above ground pump house would be inconvenient, unsightly or hazardous

Ground-surface noise is eliminated It can be used where shaft elongation problems are created by very

deep settings or when the well is not straight

DISADVANTAGES OF SUBMERSIBLE PUMP

Operating parts are inaccessible and difficult to inspect The cost of submersible pump is higher than that of an

ordinary pump If a gasket is ruptured or lose its integrity, this causes the pump

to leak and corroded the internal components and made it to fail

If the pump needs to be repaired or replaced it may be more difficult to retrieve for being submerged in water

ADVANTAGES OF SUBMERSIBLE PUMP OVER VERTICAL TURBINE PUMP (VTP)Size and Complexity: A submersible system is much simpler. The motor and pump are coupled directly together, so no shaft stabilization is needed and no additional moving parts are necessary. Whereas a VTP requires a drive shaft to couple the motor and pump, it has many more moving parts than a submersible.

A VTP has more components spread out over a greater distance, making handling and installing systems weighty. Since a submersible is far easier to handle and install.

In the most cases VTP operate at half of the RPM of a submersible. To compensate a VTP requires more stages or larger turbine bowls to generate the same performance as the equivalent submersible.

Larger Well Casing: The well casing of a VTP must be larger than a submersible. This can increase installation costs. A submersible may be installed in a well that is not completely straight, whereas a well with a VTP must be completely straight to avoid shaft fatigue and premature failure.

ADVANTAGES OF SUBMERSIBLE PUMP OVER VERTICAL TURBINE PUMP (VTP)Pump House Requirements: A VTP motor is aboveground, it requires a pump house to protect it from weather and vandalism, as well as to suppress noise. On the other hand, a submersible system does not require a pump house at all. Its underground location reduces risk of damage from weather, vandalism, and accidents. In addition a submersible does not generate the noise like a VTP.

Continuing Maintenance: A VTP requires regular lubrication, packing, and shaft or impeller adjustments. This simply is not the case with a submersible. It is designed to spend its entire life under water with no additional maintenance.

Efficiency and Starting: In VTP the motor efficiency is lost due to frictional losses in the line shaft. These losses are typically one to two horsepower per 100 feet of depth and generally exceed the electrical losses in the drop cable for a submersible system. In a VTP installation the motor must not only moving the pump but also the entire drive shaft and its associated hardware. Submersible installations have a lower moment of inertia, which means faster and easier starting.

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