What are the 2 types of gear pump

Gear pumps are vital components in hydraulic systems, used to transfer fluids efficiently. But did you know there are two primary types? Understanding whether an external or internal gear pump suits your needs can save time and cost. In this post, we'll explore the differences and applications of both gear pump types.

What Is a Gear Pump?

Definition and Basic Working Principle

A gear pump is a type of positive displacement pump. It uses gears to move fluids through a system by trapping fluid in between teeth and forcing it out under pressure. This mechanism ensures a steady, reliable flow, making it ideal for various applications.

Gear pumps are commonly used in hydraulic systems, fluid transfer, and lubrication. They efficiently move liquids or oils, making them essential in machines that require a consistent and controlled flow of fluid.

Why Use Gear Pumps?

Gear pumps are known for their simplicity, efficiency, and durability. Their design ensures long-lasting performance, making them a reliable choice for many industries.

These pumps are widely used in automotive, manufacturing, and agriculture sectors. They help power machinery, lubricate engine parts, and transfer fluids in production systems.

External Gear Pump – Type 1 of Gear Pump

What Is an External Gear Pump?

An external gear pump is designed with two identical gears rotating in opposite directions. These gears mesh together to transport fluid through the system. The gears are typically made from steel, cast iron, or composite materials, providing durability and resistance to wear. This design ensures efficient operation even in harsh environments. The simplicity and robust nature of the external gear pump make it a popular choice in various industries, where reliability and consistency are key.

How Does an External Gear Pump Work?

The process starts when the gears begin to rotate, creating a gap between the teeth. This separation generates suction, pulling fluid into the pump. As the gears continue rotating, the fluid is trapped in the spaces between the teeth. The trapped fluid is then displaced as the gears mesh again, pushing the fluid out of the pump. The pressure at the outlet increases as the gears re-engage, ensuring a continuous flow of fluid. This mechanism enables smooth and consistent fluid transfer, even under varying pressure conditions.

Pros and Cons of External Gear Pumps

External gear pumps are widely appreciated for their high pressure and efficiency, making them suitable for a range of applications, from automotive to industrial sectors. Their compact design saves space and allows them to be integrated into various systems without taking up excessive room. Additionally, their cost-effectiveness makes them a popular option, as they offer high performance at a reasonable price. However, these pumps are often noisy, which can be a downside in environments where noise reduction is important. Moreover, they are not the best choice for high-viscosity fluids, as thicker liquids may result in reduced efficiency and performance.

Common Applications of External Gear Pumps

External gear pumps are commonly used in engine oil systems, where they help circulate oil throughout the engine to ensure proper lubrication. They are also a critical part of industrial lubrication systems, providing continuous lubrication to machinery to prevent wear and breakdowns. Additionally, these pumps are used in high-pressure hydraulic units, where they effectively maintain fluid transfer under high-pressure conditions. From construction equipment to manufacturing machinery, external gear pumps are essential in applications requiring reliable and efficient fluid movement.

Internal Gear Pump – Type 2 of Gear Pump

What Is an Internal Gear Pump?

An internal gear pump is made up of two gears: one external gear and one internal gear. These gears are positioned with an offset center, allowing the internal gear to rotate inside the external gear. This design ensures smooth fluid movement. A crescent-shaped spacer is used to guide the fluid through the chamber between the gears, preventing leaks and ensuring efficiency. The combination of the gears and the spacer provides a reliable, consistent flow of fluid.

How Does an Internal Gear Pump Work?

When the gears unmesh, the pump creates suction, drawing fluid into the chamber. As the gears continue to rotate, the fluid is trapped between the teeth and moved through the pump. When the gears re-engage, the trapped fluid is forced out under pressure. This continuous, smooth flow is ideal for handling fluids that need to maintain a consistent, low-pulsation flow. The design helps minimize wear and tear on the pump, contributing to its longevity.

Pros and Cons of Internal Gear Pumps

Internal gear pumps have several advantages. They operate quietly and smoothly, making them ideal for environments where noise reduction is important. These pumps are also perfect for handling viscous fluids, such as oils, paints, or syrups. However, they have a lower pressure range compared to external gear pumps, limiting their use in high-pressure applications. Additionally, the more complex design of internal gear pumps means they are typically more expensive and require more maintenance.

Where Are Internal Gear Pumps Used?

Internal gear pumps are commonly used in industries where smooth, precise fluid handling is necessary. They are frequently used in food and beverage processing, where consistency in the flow of viscous fluids like chocolate or oils is crucial. These pumps are also found in fuel handling systems, where precise, quiet operation is needed. In the chemical and paint industries, internal gear pumps efficiently move thick liquids and coatings, ensuring accurate application and minimal waste.

Comparison Table – External vs. Internal Gear Pumps

External gear pumps are often chosen for high-pressure applications and low-viscosity fluids due to their simple design and reliability. They can be noisy, but they efficiently handle demanding industrial tasks. On the other hand, internal gear pumps are quieter and more suited for thicker, more viscous fluids. They offer a smoother operation and are widely used in sensitive environments such as food processing, fuel handling, and chemical industries.

How to Choose Between the Two Gear Pump Types

Factors to Consider

When deciding between an external and internal gear pump, several factors should be evaluated. First, fluid viscosity plays a major role. External gear pumps excel with low-viscosity fluids, while internal gear pumps are better suited for thicker, high-viscosity liquids. Next, consider the required pressure—external gear pumps are designed for high-pressure applications, making them ideal when this factor is crucial. The application environment is another key consideration; internal gear pumps are quieter and smoother, making them perfect for noise-sensitive settings. Finally, weigh the cost and maintenance concerns. External gear pumps are simpler, more cost-effective, and require less maintenance, whereas internal gear pumps tend to be more complex, requiring higher maintenance but offering smoother performance.

Real-World Use Case Scenarios

In a mobile hydraulic system, where high pressure and low-viscosity fluid handling are essential, an external gear pump is the clear choice. Its design can efficiently handle demanding pressures and is well-suited to the fluid types used in mobile applications. On the other hand, for a chocolate manufacturing plant, an internal gear pump would be ideal. The plant requires smooth, consistent fluid flow, and the chocolate's high viscosity demands a pump that can handle such fluids quietly and efficiently. Internal gear pumps provide the precise control needed to maintain the quality of the product while operating smoothly in a noise-sensitive environment.

Conclusion

There are two main types of gear pumps: external and internal. External gear pumps are ideal for high-pressure, low-viscosity fluids, while internal gear pumps excel at handling thicker, viscous liquids. Choosing the right pump depends on your specific application needs. It's always a good idea to consult with hydraulic system experts before making a purchase to ensure the best choice for your system.

JunFu has years of experience in production of Hydraulic equipment. Therefore, If you have any questions about gear pumps, feel free to contact us anytime for more information.

FAQ

Q: Are Gear Pumps Suitable for All Fluids?

A: It depends on the viscosity and chemical composition of the fluid. Gear pumps work best with fluids that match their design specifications.

Q: Can Gear Pumps Run Dry?

A: Not recommended — running dry can cause severe wear and damage to the pump's internal components.

Q: Which Type Lasts Longer?

A: The lifespan depends on the application, maintenance, and build quality. Proper care can extend the lifespan of both types.

Q: How Do You Maintain a Gear Pump?

A: Regular inspection, lubrication, and cleaning of seals and gears are essential to maintain optimal performance.