PUMPS INTRODUCTION

A pump is a device or an apparatus used for conveying a fluid from one point to other, usually through a pipe. ? A pump may, therefore, be defined as a mechanical device which translates the mechanical energy imparted to it from an external source (electric motor, diesel engine or even manual energy) into hydraulic energy in the fluid handled by it.

TYPES OF PUMPS

TYPES OF PUMPS ? POSITIVE DISPLACEMENT PUMPS ? 'Reciprocating' and 'Rotary pumps' are called positive displacement pumps, because the medium pumped together with any air which may have entered into the suction pipe gets positively displaced from the suction side to the delivery side at every revolution. ? A natural consequence of this is that its delivery pressure is not fixed as in a centrifugal pump, but will rise to high values if delivery becomes restricted. A centrifugal pump on the other hand builds up a definite maximum pressure determined by its speed and will work only when the pump casing and the suction pipe are entirely filled with water and no air has entered in. ? ROTODYNAMIC PUMPS ? These pumps are rotary machines. Essential part of such pump is a rotor called impeller which is mounted on a shaft and is driven continuously in one direction. ? Formed on the impeller are blades or vanes so shaped that they increase the pressure of the liquid flowing between them, A fixed casing accommodates the rotor and conducts the liquid from the inlet branch of the pump to the outlet branch. The example of rotodynamic pumps are 'centrifugal pumps'.

5. DISPLACEMENT PUMPS ? PROGRESSING CAVITY PUMPS ? Progressing cavity pumps belong to the group of rotating positive displacement pumps. They are self-priming, valve-less, and due to their high process liability and suction capacity they are often used for the continuous, gentle conveyance and precise dosing - in proportion to speed - of difficult media. ? Applications ? Rotary lobe pumps are preferably used for media with the following characteristics ? fluids with or without solid contents (Max. solid size up to 150 mm) ? low to high viscosity (1mPas to 3 millions mPas) ? Thixitropic and dilatant ? shear sensitive ? abrasive ? non-lubricating and lubricating ? aggresive (ph 0 -14) ? adhesive ? toxic

6. DISPLACEMENT PUMPS ? ROTARY LOBE PUMPS ? Rotary lobe pumps belong to the group of rotating positive displacement pumps. Thanks to their compact design, high performance density and operational safety they are often used to continuously and gently convey and dose - in proportion to speed - difficult media. ? Applications ? Rotary lobe pumps are preferably used for media with the following characteristics ? fluids solid-loaden or free of solids ? low to high viscosity (1 mPas to 50.000 mPas) ? shear-sensitive ? abrasive ? lubricating and non-lubricating

7. DISPLACEMENT PUMPS ? DOSING PUMPS ? This description is given by the reciprocating movement of the displacer, in the form of a plunger or a diaphragm, which alternately increases and decreases the working space. In order to prevent return flow of the conveyed medium, the working space has to be closed by two valves. ? During the backward movement of the displacer, the working space increases and a vacuum is formed relative to the pressure in front of the automatic suction valve. Due to this pressure difference, the suction valve opens and the conveyed fluid is sucked into the working space. Once the displacer reaches its rear dead-center position, the suction stroke ends. The suction valve closes by its own weight or by an additional spring load. During the forward movement of the displacer, the working space decreases. As a result, the pressure increases. When the pressure increases to slightly above the discharge pressure, the automatic discharge valve opens and the fluid volume is now discharged from the working space. In the front dead-center position, the pressure valve closes. Then the next stroke cycle begins. ? n most reciprocating positive displacement pump designs, the flow rate depends only minimally on the discharge pressure. This entails a rigid pressure characteristic curve. Furthermore, the flow rate has a linear dependency on the stroke length and stroke frequency. Reciprocating positive displacement pumps are therefore suited to the conveyance and precise metering of fluids across a wide pressure and flow rate range.

8. DISPLACEMENT PUMPS ? Dosing Pumps Applications ? Rotary lobe pumps are preferably used for media with the following characteristics ? fluids abrasive (suspensions with SiO2, Al2O3, catalysts, abrasive pastes) ? explosive (hydrogen, silanes) ? extreme purity (antibiotics) ? high vapor pressure (liquefied gases) ? corrosive (HCl, HF, HNO3) ? radioactive (plutonium / uranium salt solutions) ? reactive (water glass, sodium, aluminum alkyl) ? bad lubricating (liquid gases) ? sterile (lecithin, vegetable oils, dairy products) ? toxic (chlorine, bromine) ? valuable (spice extracts, volatile oils)

9. DISPLACEMENT PUMPS ? PISTON/PLUNGER PUMPS ? Plunger pumps, also often just called "piston pump" by layman, belong to the group of oscillating positive displacement pumps - one of the oldest pump types. The displacers in plunger pumps are moved/pressed by crankshafts which is integral to the pump and the pump has one or more cylinders. The displacer of this pump is called “plunger”. In contrast to piston pumps the plunger “dives” through a fixed seal into a sealed off working space, displacing the fluid. The seal in piston pumps is oscillating with the displacer (= piston) in the same time. Check valves in the inlet and outlet ports of the cylinder make sure that the fluid is being pushed/pressed in the right direction. At least one plunger dives in its cylinder on each crankshaft’s rotation and gets withdrawn once taken back by the crankshaft. The plunger diving into the cylinder changes displaces a volume of fluid and, whilst withdrawing it draws in a volume of fluid i.e. the pump is pumping. In order to keep the pulsation of the pumped fluid as low as possible, an odd number of cylinders is used.

10. DISPLACEMENT PUMPS ? Piston/Plunger Pumps Applications ? High-Pressure Cleaning ? Water Hydraulics ? Oil Hydraulics ? Descaling ? Process Technology ? Metering Systems ? Biotechnology ? Hydraulic Pressure Testing ? Energy Saving Fluid Transportation ? Drilling Service ? Water Injection ? Fracking ? Waterjet Cutting

11. DISPLACEMENT PUMPS ? VACUUM PUMPS ? The vacuum pumps and compressors are rotary positive displacement pumps that cover a wide range of applications. The applications are in chemical, petrochemical, pharmaceutical, paint industries as well as general industries. ? The internals of the fluid ring vacuum pump or compressor are partially filled with fluid in operation. Casing and port plates form the internals, where the eccentrically mounted rotating impeller forms a fluid ring. The fluid ring forms a cell between the impeller blades, that expands during rotation and thus draws the gas through the suction port. As the impeller rotates further, these cells are getting smaller and consequently compressing the gas through the discharge port. Together with the gas, a part of the fluid will be expelled through the discharge port that is separated from the gas in the separator. ? By means of a flexible discharge port in the port plate, the fluid ring vacuum pump operates with maximum efficiency in the whole range of suction pressure. The port opening adapts to the actual compression ratio, so that over compression will be avoided.

12. DISPLACEMENT PUMPS ? Vacuum Pumps Applications ? The major application of liquid ring vacuum pumps and compressors is in the handling of wet gas and vapours that will condense partially during compression. Because compression is near isothermal, these machines are specifically suitable for the handling of explosive or polymerising gases or vapours.

13. DISPLACEMENT PUMPS ? PISTON DIAPHRAGM PUMPS ? Wherever abrasive, aggressive and toxic fluids and slurries are conveyed, hermetically sealed, oscillating displacement pumps are used. Even for extreme operating temperatures and heterogeneous mixtures with high solids content, piston diaphragm pumps turn out to be the best pump technology for numerous applications. The advanced, unique, patented MULTISAFE? technology with the hermetically sealed, redundant double hose-diaphragm system guarantees a doubly secured transport of critical and environmentally hazardous fluids. ? Applications ? Rotary lobe pumps are preferably used for media with the following characteristics ? abrasive, aggressive and toxic media ? heterogeneous mixtures with high solid content ? pumping temperatures up to 200 °C ? environmentally hazardous fluids ? abrasion-free pumping ? hygienic design ? gentle transport without shearing effect

14. TYPES OF PUMPS ? CENTRIFUGAL PUMPS ? As the name implies, these pumps employ centrifugal force to lift liquids from a lower to a higher level. This type of pump in its simplest form comprises an impeller rotating in a volute casing. ? Liquid led into the centre of the impeller is picked up by the vanes and accelerated to high velocity by rotation of the impeller and discharged by centrifugal force at the periphery. ? When liquid is forced away from the centre, or as it is called the 'eye* of the impeller, a vacuum is created and more liquid flows in, consequently there is a constant flow through the pump.

15. CLASSIFICATION OF CENTRIFUGAL PUMPS ? These pumps possess the following characteristic features on the basis of which they can be classified as: ? Working head :- Low Lift, Medium Lift, High Lift ? Type of casing :- Volute, Diffusion ? Construction of casing:- Vertically Split, Horizontally Split ? Number of impellers per shaft:- Single Stage, Multi Stage ? Relative direction of flow through impeller:- Radial Flow, Axial Flow, Mixed Flow ? Number of entrances to the impeller:- Single Entry, Double Entry ? Disposition of shaft:- Horizontal, vertical ? Liquid handled:- Depending on the type and viscosity of liquid to be pumped, the pump may have a closed or open impeller. ? Specific speed :- The range of specific speed for radial type impeller is generally 10 to 60 and for mixed flow type impeller it is usually between 90 and 160. ? Method of drive:- Mono block, Separate Drive

16. CLASSIFICATION OF CENTRIFUGAL PUMPS ? Volute Casing ? In the volute type pump , which is the one most commonly used, the impeller discharges into a progressively expanding spiral casing. This casing is so proportioned as to produce equal velocity flow all around its circumference and to reduce gradually the velocity of the liquid as it flows from the impeller to the discharge thus changing velocity head into pressure head. ? Single stage pumps ? Centrifugal pumps with single closed type impeller with single suction is called single stage pumps. These types of pumps are generally used for small lifts like in agricultural activities when the head is less than 20 mts, ? Multistage pumps ? These pumps are used when sufficient head cannot be developed efficiently in single stage. These pumps may have two or more impellers operating in series i.e. the discharge of one impeller is connected to the suction of another. ? The number of impellers in series will depend upon the head against which the pump must operate, the impeller diameter, the capacity of the pump and its speed.

17. CLASSIFICATION OF CENTRIFUGAL PUMPS ? Axial Flow ? Axial flow pumps are used for the promotion of incompressible fluids and are employed for large volume flows at relatively low delivery heads. As with all types of centrifugal pumps, the energy transmission in axial flow pumps is carried out exclusively through flow-related processes. ? Axial flow pumps are centrifugal pumps in which the fluid is pumped parallel to the pump shaft. ? The flow mechanism in a centrifugal pump can generally be described as follows: Through a suction flange the liquid flows through the suction hub into the rotating impeller due to an energy fall. The pump unit absorbs mechanical energy from a drive motor through a shaft. The blades of the impeller which is permanently fixed on the shaft exert a force on the fluid and increase its angular moment. Pressure and absolute speed increase as a result. Consequently energy is being transferred to the fluid. The energy which is present in kinetic form as an increased absolute speed is usually converted into additional static pressure energy by a diffuser device. Nowadays volute casings or bladed diffusors normally are being used as diffuser devices. In combination with the impeller the diffuser device represents the so-called hydraulic of the pump. To maintain the flow there also has to be an energy fall directly behind the pump after the outlet from the discharge flange, analogous to the pump inlet. Losses occurring in the system for example due to friction or leakage flows require an increased power consumption of the pump.

18. CLASSIFICATION OF CENTRIFUGAL PUMPS ? Axial flow pumps differ in their constructive and functional characteristics due to their pre-determined installation location and the liquid to be pumped. For pumps of one model range various installation types may be implemented. The hydraulic characteristics and the pumping performance remain nearly unchanged. Main characteristics are the design of the shaft in the horizontal or vertical position, the position of the pump connections and the connection type of the pump to the drive unit using a coupling or direct assembly on the motor shaft ? Applications of Axial Flow Pump ? Irrigation ? Sewage Treatment Plants ? Cooling Water Pumps ? Drainage Systems

19. CLASSIFICATION OF CENTRIFUGAL PUMPS ? Radial Flow ? The biggest subsection of the centrifugal pumps is the radial pump. The handled liquid is exiting the impeller radially. The achieved delivery head is proportional to the impeller diameter. To realize higher heads, several impellers are put in series (multistage pumps), where guide rings lead the handled medium from radial flow to the axial inlet of the next stage. ? Radial flow pumps are centrifugal pumps in which the fluid is pumped perpendicularly to the pump shaft. ? The flow mechanism in a centrifugal pump can generally be described as follows: Through a suction flange the liquid flows through the suction hub into the rotating impeller due to an energy fall. The pump unit absorbs mechanical energy from a drive motor through a shaft. The blades of the impeller which is permanently fixed on the shaft exert a force on the fluid and increase its angular moment. Pressure and absolute speed increase as a result. Consequently energy is being transferred to the fluid. The energy which is present in kinetic form as an increased absolute speed is usually converted into additional static pressure energy by a diffuser device. Nowadays volute casings or bladed diffusors normally are being used as diffuser devices. In combination with the impeller the diffuser device represents the so-called hydraulic of the pump. To maintain the flow there also has to be an energy fall directly behind the pump after the outlet from the discharge flange, analogous to the pump inlet. Losses occurring in the system for example due to friction or leakage flows require an increased power consumption of the pump.

20. CLASSIFICATION OF CENTRIFUGAL PUMPS ? Radial Flow ? Centrifugal pumps differ in their constructive and functional characteristics due to their pre-determined installation location and the liquid to be pumped. For pumps of one model range various installation types may be implemented. The hydraulic characteristics and the pumping performance remain nearly unchanged. Main characteristics are the design of the shaft in the horizontal or vertical position, the position of the pump connections and the connection type of the pump to the drive unit using a coupling or direct assembly on the motor shaft ection type of the pump to the drive unit using a coupling or direct assembly on the motor shaft ? Applications of Radial Flow Pump ? Boiler Feed Systems ? Apparatus Construction ? Filter Systems ? Air Conditioning Industry ? Cooling Systems ? Cooling Lubricant Systems ? Plastics Industry ? Dairy Plant ? Surface Technology ? Cleaning Systems ? Re-cooling

21. CLASSIFICATION OF CENTRIFUGAL PUMPS ? Applications of Radial Flow Pump ? Shipbuilding ? Swimming Pool Technology ? Tank Systems ? Refrigeration Systems ? Irrigation Systems ? Booster Systems ? Boiler and Condensate Systems ? Washing Plants ? Filter Technology ? Water Treatment ? Hardening Systems ? Process Technology ? Chemical Industry ? Tank storage ? Liquefied gases

22. PROS OF CENTRIFUGAL PUMPS ? Simple in construction and easy to operate. ? Relatively low initial and maintenance cost. ? Comparatively silent in operation and makes less vibration. ? Very dependable and durable. ? Compact and requires less floor area for its foundation. ? Uniform and continuous flow. ? Capable of delivering large quantity of water as compared to its size and can handle sandy, gritty, and muddy water without injuring the pump. ? Suitable for high speed operation with an electric motor. No wasteful speed-reduction device is necessary. ? High efficiency. ? Can run for short periods with the delivery valve closed.

23. HORIZONTAL SPINDLE PUMPS VS VERTICAL SPINDLE PUMPS

24. TURBINE PUMPS ? The chief difference between centrifugal and turbine pump is in the impeller. The water in a turbine pump also called regenerative pump is admitted not at the centre of the impeller, but through an outside opening on the casing, ? The impeller has series of blades/vanes fixed on its outer rim, which revolve inside an annular space within the case in the clockwise direction. Water enters at the outer edge of the impeller and is propelled forward round the pump case through the annular channel, which is much larger than the width of the blades. As the water is carried along, it moves spirally from one blade to the following one, until one revolution, when it is diverted by a deflector plate to the discharge opening. ? Different types of impellers are used in this type of pump. They are semi open type and enclosed type. ? The impellers are usually made of cast iron or bronze, depending upon requirements and preferences. The passage ways through the impellers and diffusers are so designed as to give streamline flow and ensure smooth and efficient operation.

25. TURBINE PUMPS ? Liquid entering a centrifugal pump's impeller can pass between its vanes only once. It has energy added to it only while going from the impeller's eye to its rim. ? In a turbine pump, liquid re-circulates between the impeller's vanes. Because of this action, the fluid flows in a path like a screw thread (helical) as it is carried forward. Consequently, energy is added to the fluid in a number of impulses by the impeller's vanes as it travels from suction to discharge. ? These impulses have the same effect as multistaging in a centrifugal pump. A turbine pump can develop several times the discharge pressure of a centrifugal type, having equal impeller and speed. For high pressure, multistage pumps are used. ? Turbine pump is self-priming once it is filled with water. That is, any air entering it subsequently through the suction is carried along with the water and delivered through the delivery pipe, whereas in a centrifugal pump entry of air into the suction would make it inoperative. ? Power for a turbine pump reaches maximum at shut off, where it is the lowest on a centrifugal pump. Therefore, turbine pumps should not be operated against a closed discharge, unless a relief valve is provided. ? Turbine pumps have come into wide use for both shallow and deep wells. These are built for heads upto 300 Mts and for capacities upto 27000 LPM.

26. TURBINE PUMPS Pressure increase in the turbine pump

27. CHARACTERISTICS OF CENTRIFUGAL PUMPS ? Main and operating characteristics ? In order to obtain the main characteristics curve of a pump, it is operated at different speeds. For each speed, the rate of flow or discharge (Q) is varied by means of progressively closing or opening of a delivery valve and for the different values of Q, the corresponding values of total head (H), shaft power (P) and the overall efficiency are measured or calculated. ? The same operation is repeated for different speeds of the pump. Then the following curves are plotted. ? Head - Discharge characteristics i.e. H Vs Q. ? Power- Discharge characteristics i.e. P Vs Q. ? Efficiency - Discharge characteristics i.e. Efficiency Vs Q.

28. CHARACTERISTICS OF CENTRIFUGAL PUMPS

29. CHARACTERISTICS OF CENTRIFUGAL PUMPS ? ISO-efficiency (constant efficiency) curves ? The ISO-efficiency facilitate the direct determination of the range of operation of a pump with a particular efficiency, in other words, they evaluate the minimum and maximum percentage flows that would maintain the efficiency within say 2 % of the maximum efficiency at the design point.

30. CHARACTERISTICS OF CENTRIFUGAL PUMPS ? Constant Head and constant discharge curves ? These curves are useful in determining the performance of a variable speed to pump which the operating speed constantly varies. Characteristics of a pump under varying speeds with one of the parameters viz. Head or Discharge being maintained constant, give interesting insights into the performance of a pump

31. CHARACTERISTICS OF CENTRIFUGAL PUMPS ? Following points to be noted from the Constant Head and constant discharge curves ? With head remaining constant the discharge of the pump varies linearly with speed and characteristics are a straight line. ? With discharge remaining constant, the head developed by the pump varies as the square of the speed and characteristics is a parabola. ? With the discharge valve opening remaining constant, the power demand of the pump varies as the cube of the speed..

32. MAINTENANCE OF PUMPS ? The upkeep expense of centrifugal pumps is usually small for the reason that the only moving parts in contact are the shaft and bearings. ? The clearance between the impeller rings and case rings is almost always greater than the permissible wear of the bearings. Even if they did make contact, this would probably be detected and the pump shut down before any damage was done. ? To prevent the pumps from breakdown preventive measures to ne taken. ? Periodic Inspection & Test ? The maintenance schedule should enlist items to be attended to at different periods, such as daily, semi-annually, annually, etc, ? Daily Observations ? Leakage through packing, ? bearing temperature, ? whether any undue noise or vibration is present and ? pressure, voltage and current readings

33. ENERGY CONSERVATION ? Nearly 90 percent of the pump sets in the country are faulty. They waste 40 percent of electricity/diesel as they use three times the amount of power needed by efficient models to pump the same amount of water. ? COMMON DEFECTS ? Among the several factors affecting the overall efficiency of pump sets leading to profligate energy consumption are: (a) Mismatched Systems : a majority of us usually pay more attention to the selection of costly components viz. diesel engine and electric monoblock pump, while less attention is directed to selection of pipes, foot valves and pipe fittings. Most of us buy these separately instead of buying the system as a whole. This subsequently results in a mismatch of the components which in turn, affects the efficiency of the system. (b) Errors in the system ; Most pumping systems, popularly known as pumps, consists of 5 major components : (a) prime- mover (diesel engine or electric motor), (b) pump (c) suction line with foot valve, (d) delivery line (e) power transmission system.

34. RECTIFICATION ? Inefficiencies in the existing pumpset can be rectified by taking several simple measures such as replacing G.I. Pipes, bends and elbows with pipes, bends and accessories from low frictional material such as RPVC and HDPE. ? Old foot valve need to be replaced by low k-value foot valves. Similarly replacing the inefficient diesel engines with efficient sets and monoblocks would enhance the efficiency of the pumpset significantly. ? The best energy saver is, of course the low resistance foot valve and would result in a net saving of 10-15 per cent, for at least ten years. The low resistance improved foot valves with their smoother and larger openings ease the entry of water into the suction pipes.

35. RECTIFICATION ? In addition, the rust-free special Rigid P.V.C.(RPVC) pipes with their smooth inner surfaces and larger diameter would further reduce the flow friction, increasing the rate of discharge and as has been amply proven in the field, save 15-20 per cent of energy. Whereas, if the entire piping system of a centrifugal pump, operated by diesel engine or electric motor, is replaced by a low friction piping system, a substantial saving of 30 per cent can further be increased improving the overall system efficiency by 40 per cent. ? If the inefficient pump and high friction piping system are replaced by a properly selected high efficiency pump and a low friction piping system and if the entire pumping system is overhauled with matching monoblock, special RPVC pipes of the correct diameter, the pumpsets need use only half the amount of fuel. We could operate double the number of pumpsets that we use, at their present level of consumption. ? Besides savings, using the proper equipment for the correct value of work pays back in terms of time saved, less wear and tear on machinery and, on the whole, an increased efficiency on the system. .