Gear pumps and centrifugal pumps may both have one function, which is to pump fluid, but it doesn’t automatically mean that they can be used interchangeably; they are both designed differently.
Fluids have different levels of viscosity and may require different levels of pressure for better flow, which determines the type of pump needed. It is not just about investing in any pump but selecting the pumps that are required for the liquid. But then what makes the pumps different since they both pump fluids? This is a question that you can find the answer to as you read along this blog. It explains the gear pump vs. centrifugal pump and why the gear pump fits viscous industrial fluids.
What are gear pumps?
They were manufactured for hydraulic power applications or high-viscosity applications by utilizing mechanical action to physically compress fluid. These pumps can be electrically driven, hydraulically driven or mechanically driven, which mainly depends upon the design. The gear pumps have internal gears that rotate, and as they rotate, the fluid that enters through the suction side is trapped within the cavities of the gears, which traps the fluid as well as causing casing. Further rotation of the gears causes the fluid to move to the discharge side, which makes the gears interlock and squeeze out the remaining fluid.
Gear pumps are used for different machinery such as
- Automotive and engines (Oil pumps, backup generators, and circulating oil)
- Agricultural and construction machinery (tractors, excavators, bulldozers, forklifts)
- Industrial and manufacturing equipment(Used in circulating oil in large gearboxes, used to meter and pump isocyanates or polymers, hydraulic power units)
The advantages of using gear pumps
- They provide a wide viscosity range
- They provide self-priming capability
- They provide high efficiency and proportional output
- They have reversible operation capability
What are centrifugal pumps?
The centrifugal pump drives fluid from the pump into the discharge by using kinetic energy sourced from mechanical energy to move fluid. They function by using a rotating impeller, which creates centrifugal force to move fluid. The movement of the fluid in the impeller causes an increase in velocity, which directs it into the discharge port.
Centrifugal pumps are used in various machines, including;
- Used for water and wastewater management
- They are used for pumping crude oil, hydrocarbons and various chemical solvents
- They are used for feeding high-pressure water into industrial boilers and handling cooling tower operations.
- Used in agriculture to transfer high-volume water flow to water crops
- Used in HVAC systems to transfer hot water, condenser water or cool water.
Advantages of using centrifugal pumps
- It provides versatility and adaptability(rotation speed, impeller designs or linking units can be adjusted)
- Its design ensures a sturdy build and reduced friction, which assures a low level of friction or wear; as such, it can last longer and has low maintenance.
- It enables a high volume of fluid to move at higher speed.
- It offers high efficiency in cleaning water.
Here is why gear pumps are best for viscous fluids compared to centrifugal pumps
Positive displacement action
- The gear pump provides efficient positive displacement because it can trap fluid within its gear teeth to cause pressure that moves fluid from the inlet to the discharge as it turns.
- The centrifugal pump utilizes an impeller to push fluid from the inlet to the discharge. This mechanism is mainly used for recirculating liquids, which is not effective for thick fluids, as it does not provide enough capacity to push the fluid.
Involved in volumetric efficiency with viscosity
- Gear pumps can function effectively regardless of the level of viscosity because the fluids seal between the gear teeth and pump, which reduces internal slip.
- The centrifugal pumps reduce in effective functionality as viscosity increases.
Independence from abc pressure
- Gear pumps are able to handle different ranges of pressure; as such, they can function effectively even if the pressure increases.
- The centrifugal pump registers a drop in centrifugal flow when there is downstream resistance or pressure.
Conclusion
Both pumps function effectively; it just requires the right application of each pump. The centrifugal pump is more efficient for clean fluid or low-viscosity fluid, while the gear pumps are mainly effective for corrosive, abrasive industrial fluids. As such, if the aim is to get a pump that can move viscous industrial fluids, then the gear pumps function effectively. In order to get access to different types of pumps and the right guidance on gear pump vs. centrifugal pump, Goodwin Group is in the right position to provide the right information.
FAQ’s
Is it okay to replace a centrifugal pump with a gear pump for the same duty?
It is not advisable to replace the centrifugal pump with a gear pump for the same duty because they both operate differently.
What is the highest level of viscosity the gear pump can handle?
The highest it can handle is around 1,000,000 centipoise or around 2,000,000 cSt, which is mainly dependent on the pump type.
How long should I take to conduct maintenance on the gear pumps?
Maintenance should be done on a monthly basis, and you can also conduct an annual check.
What does self-priming mean?
This means that the pump can create air out of the suction line in order to create a partial vacuum, which pulls fluid into the pump.
Do the gear pumps handle high pressure of fluid?
They are able to handle high pressure, though it is mainly dependent on the type and design.