transportation of fluids.pptx

7/27/2019 Transportation of Fluids.pptx

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Pumps, Fans, Blowers andCompressors


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Fluids are moved by pumps, fans, blowers, andcompressors. These use work to increase the

mechanical energy of a fluid, which in turn canincrease the flow rate (velocity), pressure, orelevation of the fluid. Definitions overlap, but broadcategories can be defined -- the characterization is

based on the phase of the fluid, the flow capacity,and the required pressure change (head).

Liquids are typically moved by pumps. Gases aremoved by fans (large volume, small pressure

difference), blowers (large volume, moderatepressure difference), or compressors (large pressuredifferences). Specialized equipment is also used toproduce vacuums in process systems.


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Increase the mechanical energy of theliquid, increasing its velocity, pressure, orelevation or all three

Two types of pump: Positive displacement pumps and

Centrifugal pumps


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Apply pressure directly to the liquid by areciprocating piston, or by rotatingmembers which form chambers alternatelyfilled by and emptied of the liquid

operate by trapping a fixed volume of liquidthen releasing it to a higher pressure by

means of a piston or rotary gear


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Reciprocating Pumps Reciprocating pumps use a piston, plunger, or

diaphragm to raise the pressure of a liquid. The

pumping chambers are surrounded by one-wayvalves so that liquid can only move in from the lowpressure side and out from the high pressure side.They are classed as "single acting" if fluid is moved

only on the downstroke, or "double acting" if fluid ismoved by both sides of the piston.


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Examples of Reciprocating Pumps Piston Pumps liquid is drawn through an inlet checkvalve into the cylinder by the withdrawal of a piston andthen is forced out through a discharge check valve on thereturn stroke; max discharge of 50 atm


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Plunger Pump used for higher pressures; are singleacting and usually motor-driven; can discharge up to 1500atm or more

Diaphragm Pump

handle small to moderate amounts ofliquid, up to about 100 gal/min; can develop pressures inexcess of 100 atm


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Rotary Pumps Liquid enters through a gap between the rotating

element and pump wall at a low pressure where it istrapped. Then, as the element rotates, it squeezes theliquid out through a one-way valve on the opposite side ofthe casing

Typically, rotary pumps are used in high head, low flow

applications. They are good for high viscosity and lowvapor pressure fluids. The fluid pumped must be"lubricating"; solids cannot be present. A key differencefrom centrifugal pumps is that discharge pressure

variation has little effect on capacity Rotary pumps are common in laboratory settings because

they have constant displacement at a set speed, and socan be used as metering pumps. Rotary pumps are alsoextremely common in fluid-power applications.


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Examples of Rotary Pumps

Gear Pump


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Lobe Pump

Screw Pump


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Cam pumps

Vane pumps


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Peristaltic pump Used in the production of biochemicals

Discharge rate is almost constant The fluid is contained within a flexible tube fitted inside

a circular pump casing (though linear peristaltic pumpshave been made). Arotor with a number of "rollers","shoes" or "wipers" attached to the externalcircumference compresses the flexible tube. As the rotorturns, the part of tube under compression closes (or"occludes") thus forcing the fluid to be pumped to movethrough 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.
http://en.wikipedia.org/wiki/Rotor_(turbine)http://en.wikipedia.org/wiki/Rotor_(turbine)


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Generate high velocities, then convert the resultingkinetic energy of the liquid to pressure energy.

is a rotodynamic pump that uses a rotating impellerto create flow by the addition of energy to a fluid.

Centrifugal pumps are commonly used to moveliquids through piping. The fluid enters the pumpimpeller along or near to the rotating axis and isaccelerated by the impeller, flowing radially outwardinto a diffuser orvolute chamber (casing), from

where it exits into the downstream piping.Centrifugal pumps are used for large dischargethrough smaller heads.
http://en.wikipedia.org/wiki/Rotodynamic_pumphttp://en.wikipedia.org/wiki/Impellerhttp://en.wikipedia.org/wiki/Rotodynamic_pumphttp://en.wikipedia.org/wiki/Impellerhttp://en.wikipedia.org/wiki/Volute_(pump)http://en.wikipedia.org/wiki/Casinghttp://en.wikipedia.org/wiki/Volute_(pump)http://en.wikipedia.org/wiki/Casinghttp://en.wikipedia.org/wiki/Casinghttp://en.wikipedia.org/wiki/Volute_(pump)http://en.wikipedia.org/wiki/Impellerhttp://en.wikipedia.org/wiki/Rotodynamic_pumphttp://en.wikipedia.org/wiki/Rotodynamic_pumphttp://en.wikipedia.org/wiki/Rotodynamic_pump


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Fans discharge large volume of gas intoopen spaces for large ducts; they are low-speed machines that generate very low

pressures on the order of 0.04 atm; densityis constant

Blowers are high-speed rotary devices that

develop a maximum pressure of about 2 atmto several thousand atmosphere; densitychanges too great

transportation of fluids.pptx

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