The Reciprocating Pump Engineering Essay

The Reciprocating marrow Engineering EssayA center is a robot the like trick which helps to move smooths including fluids or gases. It is basically a hydraulic machine which converts the mechanical cleverness to the hydraulic energy. The hydraulic energy is been present in public figure of the pressure energy. there be versatile oddballs of inwardnesss such as coercive dis airment centres, velocity warmnesss, Buoyancy pumps, Impulse pumps. The heterogeneous different pumps ar as intumesce been sub- classified in various other pumps. Positive Displacement pumps argon one of the most comm only employ pumps. They argon sub-divided in to Reciprocating and roundab extinct pumps. Typical types of the Reciprocating pumps are Plunger pumps and Diaphragm Pumps. The Plunger pump is also kn declare as Piston Pumps. The Reciprocating Pumps are highly efficient pumps which are so far suitable for the actually high heads at low passs. It is a self priming type of pump as it understructure unpack the fluid from the level below the sucking flange if the suction squall is not evacuated. There should be a smooth course postulate for achieving a good efficiency (Chinnuraj, 2009).The complete system is based on the bod of the pump. The head of cylinder is been mounted with suction and go off valves. The fluid enters the pump through the suction valve and goes out threw the polish off valve. In suction stroke, suction valve opens when the plunger retracts. The fluent gets pushes out of the discharge valve in the precedent stroke. Reciprocating system has a pulsating discharge and it totally dep dying on the reanimate of the pump which bed be easily altered. The intake of the fluid in the pump is al ways at a constant mickle. They are lots personad for slurry and sludge. There are various different projects from rest of the pumps. The founding containing single-acting intercommunicate discharges fluid from only one aspect of the plunger . There is only one suction and discharge per transformation of the irritable shaft. The other target is the stunt man-acting plunger design where the suction and the discharge come ons on the either side of the piston resulting in double suction and double discharge per revolution of crack shaft.Classification of PD PumpPositive Displacement pump are been classified as followsPositive Displacement Pump circular Pump single(a) Rotor-Vane -Piston -Flexible -Member Screw-Simplex -Duplex -Triplex - multiple-Simplex -DuplexDouble ActingSingle ActingDiaphragmPiston PlungerReciprocating PumpSimplex MultiplexMulti Rotor-Gear Lobe Circumferential Piston -Screw(Gates, 2010)Working Principle of Reciprocating PumpThe works principle of the Reciprocating pump is very simple it operates on the principle that a volume of liquid would be displaced by solid equal to its own volume. The mechanical energy is been converted in to the pressure energy and takes place due to the suction of the liqui d into the cylinder in which the piston is having a reciprocating exertion (linear motion-threw and fore). This exerts the thrust on the fluid and hydraulic energy gets change magnitude gradually. In single acting reciprocating pumps, a single piston moves forrad and backward in a closed tight cylinder. The linear motion of the piston in the cylinder is been given by connecting piston to the crosspatch with the help of a connecting perch. An electric motor is been used to give motion to the crank and the rotary motion is been converted to the linear motion by the help of the connecting rod. The working principle is somewhat similar to the car engines where the piston has the same movement threw some similar sympathetic of motions. In Reciprocating Pump, the suction valve allows the fluid to enter where as the discharge valve tends to discharge it from the cylinder (Chinnuraj, 2009).http//www.lcresources.com/resources/getstart/pump.gifnumber 01 Working Principle of Reciprocating Pump (Getting Started in HPLC, 2001)Types of Reciprocating PumpsThe Reciprocating Pumps are usually classified as followsDirect or Indirect actingSimplex (single) or duplex (double)Single acting or double acting mellow pressure or low pressureThe direct acting pumps are one of the most common type of pump been used. It is been known so as in the particular design the pump rod is a direct extension of the piston rod in which the lower end is been directly connected to the piston in the cylinder. Single and Double march pumps is as mentioned earlier. Single action has a single suction and a single discharge per revolution and Double action pump has devil suctions and discharges per revolution.ApplicationsReciprocating Pumps have a very large contribution to the society with jam of uses. They are been used for no. of small and large applications including irrigation, chemic movement, sewer movement, flood control and marine applications and even legion(predicate) more. Designing factors like coat and type of pump depends on the usage.They are been used in various purposes such asHigh pressure jets The purpose of pumps used is producing a direct high jet pressure of the fluid. The inlet eat is at a constant take to the woods and pressure but the discharge at a high velocity and therefore results to high heart of pressure.Chemical Injection The Reciprocating Pumps are even used in the chemical industry where they need to inject the chemical in a original flow or pressure. It is been used at very high exact and accuracyIrrigation The pump is usually used in farms and gardens to distribute peeing throughout equally and automatically without any sort of manual efforts.sewer movement The pump are been used to move the slurry or cloaca material in a very easy and automatic way. The primary(prenominal) advantage is the time constraint. It takes very less time as closely as it is very cheap compared to other techniques.Marine application The abundant amou nt of usage is being the marine sector where they need to use water movement from one part to other through a pump. The pump is very easy and compact source of product which can be installed very easily and without any tutelage in future. In marine field pump is used forLubricating oil transfer open fire oil transferAuxiliary circulating and condensate.Domestic uses Reciprocating pump is even used as domestic purposes. In olden days it was very common to use a hand pump which was a type of reciprocating pump with help of which we can pull the underground water for various purposes such as home usage, irrigation, construction, small scale industry and many more.Discharge and Pressure CharacteristicsThe working principle and the characteristic is been keenly detect earlier. It is been very easy to analyse the discharge and pressure constraints of reciprocating pumps. The discharge of the reciprocating pump is not uniform and stable. The discharge characteristic depends on notch flow of fluidFluid assiduousnessSpeed of reciprocating pistonPump size and designThe discharge is completely non-uniform and throttling. The pulsating property of the discharge fluid is seen. This is because the piston moves at a high velocity hitting the fluid out wards and the hitting of the piston is not a continuous act which can give a uniform pressure outlet. Despite of vital use, the reciprocating pump calm down encounter pulsating pressure which is been seen at the suction and discharge lines. This pulsating give is result of the interaction between unstable flow of fluid and the high- male monarched characteristics of the fluid particles. Pressure pulsating in the suction line can demand to the cavitation, either in the line itself or in the cylinder chamber. If cavitation is been see at the start of the piston stroke than the piston loading and the crank assembly can fail. Because of all this factors it reduces the life of the pump and also affects the recourse conditio ns (K A Edge, 1997)Pump Performance and EfficiencyThe head of flow against which the pump works is called total head, H. The total head of the pump is the energy imparted to the liquid by the pump.H = hd hgTherefore, the effective head of a pump is expressed by the following equationH = Equation 1 (Sorensen, 1969)This design principle of the pump work similarly as that of the turbines. The energy of supplied to the pump by the rotating shaft to move the piston inside the cylinder, in terms of bhpEnergy, e = =The capacity of the pump is proportional to its displacement reaction per whole time, D. Assuming 100% of the hydraulic efficiency of the pump, the displacement of the pump is calculated. The displacement is the calculated capacity of pump which is proportional toCross-sectional area of piston, ALength of the stroke, SNo. of cylinders, nPump speed in rpm (gallons per minute)D = (A - S - n - rpm) / 231In case of double acting pumps, the cross sectional area is twice to be tak en in to account from which the cross sectional area of piston rod (a) is subtracted.In double acting pumps, D = ((2A a) - S - n - rpm) / 231The volumetrical efficiency of the pump is expresses in terms of percentage. It is directly proportional to the ratio of the total discharge volume to piston displacement.The ratio (r) is equal to (c + d)/d whereD = volume displaced by pistonC = Additional volume between the discharge and suction valves.So it is clearly seen that smaller the ratio, the volumetric efficiency is tend to be better. Mathematically it is expressed asVE = 1 (P - b - r ) SWhere P is pressureB is the liquid compressibility factorR is volume ratioS is the slip. (Joe Evans, 2004)losings in Reciprocating PumpThere are various losses which are been encountered in the pump such asFrictional lossesHead lossesHeat transfer lossesThe various losses occur due to the friction and the movement of the fluid. It depends on the head flow of fluid, density of the fluid, piston s peed and the fluid suction capacity as well as discharge. There are lots of constraints been involved here, but it just can be minimised but not 100% avoided.AdvantagesEasy in workingInexpensiveCompact and Easy to installLow maintenanceWorks at high speed and at low powerDisadvantagesThe major disadvantage of the reciprocating pump is that it has a discontinuous discharge flow which with variable pressure and hence it adversely affects the potential of the pump usage. There are various techniques been used to minimise the pulsating feature but it still tend to create problems. There are some technical ways used to minimise it by using sensors or throttle valves which keeps the discharge pressure uniform, but it does affect the overall flow and creates a kind of friction to the overall discharge pressure.Secondly, it has a disadvantage that it is prone to flow separation at the lowest pressure point in the system. The design of the system is such that this problem would be there and cannot be solved. The various different tries and practical experiments to minimise it would not work till the design is not thoroughly changed. In spite of all this disadvantages it is still a very useful product and widely used.