Internal Gear Pumps

The internal gear pumps has an external gear that is generally used to drive the internal gear. The internal gear , which is smaller than the external gear rotates on a pin and operates inside the external gear. The gear creates voids as they come out of the mesh and liquid flows into the pump. As the gears come back into mesh, volumes are reduced and liquid is forced out the discharge port. Liquid can enter the expanding cavities through the external teeth or recessed areas ion the head, alongside the teeth. The pump head prevents liquids from flowing to the suction port from the discharge port.

The external gear is driven by a shaft supported by bearings. The internal Gear contains a bearing rotating on a stationary pin in the pumped liquid. Depending on shaft sealing arrangements, the external shaft support bearings may run in pumped liquid. This is an important consideration when handling an abrasive liquid and can wear out a support bearing.

The speed of the internal gear pumps is considered relatively slow compared to centrifugal types. Speeds up to 1,150 rpm are considered common. Because of their ability to operate at low speeds, internal gear pumps are well suited for high – viscosity applications and where suction conditions call for a pump with minimal inlet pressure requirements.

For each revolution of internal gear pumps, the gears have a fairly long time to come out of mesh allowing the spaces between gear teeth to completely fill and not cavitate. Internal gear pumps have successfully pumped liquids with high viscosity and very low viscosity.

The internal gear pumps is non-pulsing, self-priming, and can run dry for short periods.  They're also bi-rotational, meaning that the same pump can be used to load and unload vessels.  Because internal gear pumps have only two moving parts, they are reliable, simple to operate, and easy to maintain. The External Gear is of Mild Steel and the Internal Gear is of PB10 Material, which makes this pump fireproof. The industrial gear pumps are available in Mild Steel and Stainless Steel.



HOW INTERNAL GEAR PUMPS WORK :-
1. Liquid enters the suction port between the rotor (large exterior gear) and idler (small interior gear) teeth. The arrows indicate the direction of the pump and liquid.




2. 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 discharge ports.




3. The pump head is now nearly flooded, just prior to forcing the liquid out of the discharge port.  Intermeshing gears of the idler and rotor form locked pockets for the liquid which assures volume control.




4. 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.

ADVANTAGES : - Only two moving parts Only one stuffing box Non-pulsating discharge Excellent for high-viscosity liquids Constant and even discharge regardless of pressure conditions Operates well in either direction Can be made to operate with one direction of flow with either rotation Single adjustable end clearance Easy to maintain Flexible design offers application customization

APPLICATIONS : - All varieties of Fuel Oil & Lube Oil Resins And Polymers Solvents Paints Inks and Pigments Varnish Castor Oil