Sliding Vane Vs. Centrifugal Vs. Gear Pumps

April 22, 2022

Sliding Vane, centrifugal, and gear pumps are three of the most commonly used pumps for fluid handling, all of which have different purposes and best areas of application. It can sometimes be difficult to choose the one that meets your exact requirement; however, understanding the difference between the three pumping technologies and their working principles will help you make an informed decision. In this article, we’ll cover everything you need to know about these pumps in detail:

Sliding Vane Pumps

A sliding vane pump is a positive displacement pump that consists of blades or vanes that slide in and out of slots in the pump rotor, eccentrically supported in the cam to form a crescent shaped cavity. This cavity traps a certain amount of fluid and forces it into the discharge pipe with each rotation. What goes in is exactly what comes out. No more, no less. These pumps provide a constant flow of fluid at a given speed, and can overcome pressure differences. They are also referred to as rotary vane or constant-volume pumps.

Centrifugal Pump

Centrifugal Pumps are one of the most commonly used pump types in the world. It consists of an impeller, which rotates and creates a centrifugal force that imparts Kinetic energy to the fluid, inducing a flow from a low level to a high level. These pumps are widely used within mining, manufacturing, and agricultural industries due to their large volume handling capacity, small size, user-friendliness, and easy maintenance features.

Gear Pumps

A positive displacement gear pump uses the meshing of two or more rotating gears to form a liquid seal with the casing, which creates a vacuum at the inlet and moves the fluid to the outlet. These pumps are mainly used because of their flow-rate & volume controlling capability. If the pressure within the system remains constant, these pumps can provide more or less fixed fluid flow rate.

Differences – Sliding Vane vs. Centrifugal vs. Gear Pumps

Factors	Sliding Vane Pumps	Centrifugal Pumps	Gear Pumps
Performance	Flow rate remains constant regardless of pressure at inlet	Flow rate varies with pressure at inlet	Flow rate remains constant
Fluid Viscosity Range	Designed for low viscosity fluids (up to 500 CPs)	Recommended for fluids with lower viscosity (up to 500 – 600 CPs)	Ideal of high viscous fluids
Application	To transfer Fuel, Aviation Fuel, LPG, Ammonia, refrigerant coolant, etc…	Used for general water supply, to pump sewage agriculture, fire & safety, heating & cooling application.	Mainly used to pump ink, paint, chocolate, honey, gels, tar, resin, bitumen, lube oil, chemicals, and highly viscous food syrups, etc…
Efficiency	Excellent. Works better when pressure increases	Average. Peaks at specific pressure, variations drastically reduce efficiency	Designed to perform as pressure rises
Fluid Temperatures	handles a wide range of fluid temperatures	Can handle up to 120°C	Can handle up to 400°C
Can they Run Dry?	No	No	Yes, but only for short period of time (provided the gear has self-lubrication)
Self-Priming	Yes	No	Yes
Pumping Efficiency	Excellent	Good	Good (based upon fluids being handled)s
Energy Cost	Excellent	Good	Average
Maintenance	Not so expensive	Cheaper	Bit expensive
Flow Control	Excellent	Moderate	excellent
Initial Cost	Moderate	Moderate	Expensive

Benefits and Drawbacks

Now that we understand the principles of operation & differences for each type of pump, let us go through the benefits and drawbacks associated with each technology:

Sliding Vane Pumps

Pros:

• Highly efficient
• Capability to manage thin/less viscous fluid effectively
• Self-priming.
• Operates at a stable flow rate, thereby ideal to use for motoring
• Limited capacity with high - pressure requirements

Cons:

• Fluid delivery is pulsating in nature
• Not suitable for liquid with solid contents
• Not suitable for highly viscous fluid.
• Cannot close the discharge valve
• Requires safety valve at discharge to prevent mechanical failure

Centrifugal Pumps

Pros:

• Zero chance of leakage unless casing is broken.
• Lower rate of pump deterioration.
• It functions with minimum noise.
• Magnetic coupling will break under heavy load thus saving the motor.
• Gap between the motor & pump will restrict the entry of fluid.

Cons:

• Coupling might slip in case of a sudden heavy load
• If the pumping liquid contains any iron particles, will be collected on the impeller due to magnetic drive, which may leads to clog the pump.

Gear Pumps

Pros:

• Can handle high density or viscosity
• Self-priming.
• Highly Efficient
• Easy to Use and Maintain
• Very controllable

Cons:

• Produces Loud Noises
• Displacement Cannot Be Adjusted
• Not suitable for fluids with solid/abrasives.

When, Where & Which Pump to Use?

To choose between Sliding Vane, Centrifugal, and Gear Pumps is not always easy without a clear understanding of its features and differences. Below are some of the industries where these pumps are commonly used:

Industry	Sliding Vane Pump	Centrifugal Pump	Gear Pump
Agriculture	✗	✓	✗
Fire & Safety	✗	✓	✗
Food & Beverage	✓	✓	✓
Pharmaceutical	✗	✓	✗
Manufacturing	✗	✓	✗
Waste Management	✓	✓	✗
Petrochemical	✓	✓	✓
Oil & Gas	✓	✓	✓