Introduction
Gear pumps are positive displacement pumps that use rotating gears to pump fluid or liquid. These pumps are commonly used in various industries, including agriculture, aerospace, and construction. There are two types of gear pumps: external gear pumps and internal gear pumps. In this article, we will discuss these two types of gear pumps in detail.
External Gear Pump
An external gear pump is a type of positive displacement pump that uses two external gears to create a vacuum, which draws fluid into the pump. The fluid is then pressurized and expelled through the outlet of the pump. The external gear pump is a popular choice for hydraulic systems because of its ability to handle a wide range of viscosities.
External gear pumps have two gears, one of which drives the other. The teeth on both gears mesh together, and as they rotate, they trap liquid between the gear teeth and pump it from the inlet to the outlet of the pump. The external gear pump can be designed to handle various liquids, including water, oil, and chemicals.
One significant advantage of the external gear pump is its simplicity. It has relatively few moving parts, which makes it easy to maintain and repair. Additionally, external gear pumps are compact and can be used in applications where space is limited.
Internal Gear Pump
The internal gear pump is a type of positive displacement pump that uses two or more meshing gears to pump fluid. The gears are enclosed within a tight fitting housing or casing, which creates a tight seal between the pump''s inlet and outlet. The rotation of the gears causes a vacuum drawing fluid into the pump, which is then pressurized and expelled through the outlet.
Internal gear pumps are commonly used in various industrial applications, including chemical processing, food processing, and oil and gas production. They are also used in hydraulic systems, lubrication systems, and fuel delivery systems.
Internal gear pumps have an outer gear, which is known as the ring gear, and an inner gear, which is known as the rotor. As the rotor rotates, it engages with the ring gear, creating pockets of air between the teeth. The fluid is then drawn into these pockets and pumped through the outlet of the pump.
One significant advantage of internal gear pumps is their ability to handle high-viscosity liquids. Unlike external gear pumps, internal gear pumps can handle liquids with a viscosity up to 1,000,000 centipoise, making them ideal for applications such as the pumping of molasses, tar, and various chemicals.
Comparison between External Gear Pump and Internal Gear Pump
While both external and internal gear pumps use gears to pump fluids, there are some significant differences between the two types of pumps.
The most notable difference is their design. External gear pumps have two gears, and the gears are located outside the pump casing. On the other hand, internal gear pumps have an outer gear and an inner gear, and the gears are located inside the pump casing. This design allows internal gear pumps to handle higher viscosity liquids than external gear pumps.
Another difference between the two pumps is their efficiency. Internal gear pumps are generally more efficient than external gear pumps because of their tighter tolerances. The tighter clearance between the gears in an internal gear pump reduces leakage and increases the efficiency of the pump.
Conclusion
Gear pumps are positive displacement pumps that use rotating gears to pump fluids. The two types of gear pumps are external gear pumps and internal gear pumps. External gear pumps have two gears located outside the pump casing, while internal gear pumps have an outer gear and an inner gear located inside the pump casing.
External gear pumps are commonly used for hydraulic systems, while internal gear pumps are used in various industrial applications, including chemical processing and food processing. Internal gear pumps are also ideal for pumping high-viscosity liquids, while external gear pumps are best suited for fluids with lower viscosities.
Both external and internal gear pumps have their advantages and disadvantages, and the selection of the appropriate pump depends on the specific application. Nevertheless, understanding the differences between the two types of gear pumps is essential for choosing the proper pump for a particular task.
