TYPES OF ROTARY PUMPS (GEAR PUMP)

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 TYPES OF ROTARY PUMPS (GEAR PUMP) 

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The rotory pumps classified into six general types these are, 

1. GEAR PUMP
2. LOBE PUMP
3. VANE PUMP
4. PROGRESSIVE CAVITY PUMP
5. PERIPHERAL PUMP
6. SCREW PUMP

1). GEAR PUMP:

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The hear pump classified into two different types these are, 

1. EXTERNAL GEAR PUMP
2. INTERNAL GEAR PUMP

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1). EXTERNAL GEAR PUMP:

• In external gear pumps, two identical gears rotate against each other.

• The motor provides the drive for one gear. This gear in turn drives the other gear. A separate shaft supports each gear, which contains bearings on both of its sides As the gears come out of the mesh, they create expanding volume on the inlet side of the pump.

• Liquid flows into the cavity and is trapped by the gear teeth while they rotate. Liquid travels around the interior of the casing in the pockets between the teeth and the casing. The fine side clearances between the gear and the casing allow recirculation of the liquid between the gears. 

• Finally, the meshing of the gears forces liquid through the outlet port under pressure. As the gears are supported on both sides, the noise levels of these pumps are lower and are typically used for high-pressure applications such as the hydraulic applications. 

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2). INTERNAL GEAR PUMP:

• Internal gear pumps have only two moving parts.They can operate in either direction, which allows for maximum utility with a variety of application requirements. 

• In these pumps, liquid enters the suction port between the large exterior gears, rotor, and the smaller interior gear teeth, idler. The arrows indicate the direction of the pump and the liquid. 

• Liquid travels through the pump between the teeth of the ‘gear-within-a-gear’ principle. The crescent shape divides the liquid and acts as a seal between the suction and the discharge ports. 

• The pump head is now nearly flooded as it forces the liquid out of the discharge port. Rotor and idler teeth mesh completely to form a seal equidistant from the discharge and suction ports.

• This seal forces the liquid out of the discharge port. The internal gear pumps are capable of handling liquid from very low to very high viscosities. 

• In addition to superior high-viscosity handling capabilities, internal gear pumps offer a smooth, nonpulsating flow. Internal gear pumps are self-priming and can run dry. 

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