- Gear pumps are positive displacement pumps that move fluid using two interlocking gears to create consistent, pulse-free flow
- Two main types exist: external gear pumps (two identical gears) and internal gear pumps (one gear inside another)
- Best suited for high viscosity fluids like oils, paints, and resins with pressures up to 7500 psi
- Flow rate directly correlates with gear rotation speed, making them ideal for precise metering applications
- Self priming capabilities and simple design make them reliable for industrial hydraulic and fluid transfer systems
When you need consistent, reliable fluid transfer in industrial applications, gear pumps deliver the precision and durability your operations demand. These positive displacement pumps have powered heavy equipment and industrial systems for over 400 years, earning their reputation through simple design and dependable performance.
Unlike centrifugal pumps that rely on impeller speed, gear pumps use mechanical displacement to move exact volumes of fluid with each rotation. This makes them perfect for applications requiring precise flow control and handling of viscous fluids that would challenge other pump types.
What is a Gear Pump?
A gear pump is a positive displacement pump that moves fluid by trapping fixed volumes between interlocking gears. The mechanical action compresses and transfers fluid, creating steady flow that doesn’t depend on pressure variations like centrifugal pumps do.
The key advantage lies in the direct relationship between gear rotation speed and flow output. When gears rotate faster, more fluid moves through the system. This predictable performance makes gear pumps ideal for metering and blending operations where exact volumes matter.
Most gear pumps feature compact design with minimal moving parts, enhancing reliability in demanding industrial environments. The pump casing houses the rotating gears with tight clearances that prevent backflow and maintain pump efficiency even under varying pressure conditions.
The displacement pump design creates smooth flow with minimal pulsations compared to reciprocating pumps. This steady flow characteristic makes gear pumps particularly valuable for applications where consistent pressure and flow rates are critical for system performance.
How Gear Pumps Work
The operating principle of gear pumps centers on creating suction at the pump inlet while forcing fluid out at the discharge port. As the gears rotate, they create a partial vacuum that draws fluid into the system through the suction line.
Fluid gets trapped in cavities between gear teeth and the pump casing as gears rotate. These sealed chambers carry the pumped fluid from the suction side to the discharge side without allowing mixing or backflow. The interlocking gears maintain a liquid seal that prevents fluid from returning to the inlet.
At the discharge point, gear teeth engage and mesh together, forcing trapped fluid out under pressure. The continuous rotation creates steady, repeatable pumping action that delivers consistent flow rates regardless of downstream pressure variations.
Tight clearances between the gears and casing, typically around 10 micrometers, minimize flow slip and maintain volumetric efficiency. These precise tolerances allow gear pumps to handle high pressure applications while preventing internal leakage that would reduce performance.
The self priming capabilities of gear pumps eliminate the need for manual priming procedures. When the drive gear begins rotation, it immediately creates suction that draws fluid into the pump chamber, making startup procedures simple and reliable.
Types of Gear Pumps
Two primary designs dominate the gear pump market: external and internal gear pumps. Both operate on the same basic displacement principle but differ in gear arrangement, pressure capabilities, and fluid handling characteristics. Selection depends on specific application requirements including pressure levels, fluid viscosity, and installation constraints.
Understanding the differences between these designs helps determine the right gear pump for your application. Each type offers distinct advantages that make them suitable for different industrial uses and operating conditions.
External Gear Pumps
External gear pumps have two identical gears mounted on parallel shafts inside the pump housing. One gear is driven by a motor, while the other acts as the idler gear. These gears mesh externally with teeth on their outer surfaces.
They can use spur, helical, or herringbone gears. Spur gears are simple and cost-effective, while helical and herringbone gears provide smoother, quieter flow.
External gear pumps handle pressures up to 7500 psi and are suited for medium to low viscosity fluids. Their compact design makes them ideal for mobile hydraulic and industrial systems with limited space.
Due to tight clearances, they are best for clean fluids and less suitable for fluids with suspended particles.
Internal Gear Pumps
Internal gear pumps feature a “gear within a gear” design, where a smaller rotor gear rotates inside a larger outer gear with internal teeth. The rotor gear connects to the motor drive, while the outer gear acts as the idler.
A crescent-shaped partition separates the pump inlet and outlet, ensuring correct fluid flow. These pumps typically use spur gears due to their internal layout.
Internal gear pumps offer better suction and handle higher viscosity fluids more effectively than external pumps. Their looser tolerances allow pumping fluids with small suspended particles.
They usually operate at moderate pressures and provide bi-directional flow, making them suitable for filling and emptying applications.
The larger displacement chambers enable moving thick, viscous fluids with minimal stress, ideal for heavy oils, polymers, and other high viscosity fluids.
Gear Pump Applications
Gear pumps serve critical roles across numerous industries where consistent fluid transfer and precise flow control are essential. Their ability to handle a wide range of fluid viscosities makes them versatile solutions for challenging pumping applications.
In hydraulic power applications, gear pumps provide the steady pressure and flow needed for operating cylinders, motors, and other actuators. Construction equipment, manufacturing machinery, and mobile hydraulic systems rely on gear pumps for dependable performance under demanding conditions.
Chemical processing facilities use gear pumps for transferring acids, solvents, polymers, and specialty chemicals. The pumps’ resistance to corrosive fluids, when constructed with appropriate materials, makes them suitable for handling aggressive chemicals safely and efficiently.
The food industry employs gear pumps for moving chocolate, syrups, edible oils, and thick sauces where hygiene and precise metering are critical. Sanitary designs meet food safety requirements while delivering the accuracy needed for product consistency.
Fuel systems in marine, automotive, and industrial applications use gear pumps for diesel, gasoline, and heating oil transfer. Their self priming capabilities and reliable operation make them ideal for fuel handling systems requiring consistent supply pressure.
Metering and blending operations benefit from gear pumps’ precise flow control capabilities. Paint manufacturing, adhesive production, and polymer processing rely on accurate fluid dosing that gear pumps deliver through their positive displacement action.
Industrial lubrication systems use gear pumps to circulate lube oils through machinery and equipment. The pumps maintain consistent oil pressure and flow rates essential for proper equipment lubrication and protection against wear.
Benefits of Gear Pumps
The self priming capabilities of gear pumps eliminate complex startup procedures required by many other industrial pumps. This feature reduces operator training needs and ensures reliable operation even after extended shutdown periods.
Consistent flow output remains steady regardless of pressure variations in the system. This characteristic makes gear pumps ideal for applications where maintaining precise flow rates is critical for product quality or process control.
Simple design with minimal moving parts reduces maintenance requirements compared to more complex pump types. The basic gear arrangement has fewer components that can fail, resulting in lower maintenance costs and longer service life.
Gear pumps excel at handling high viscosity fluids up to 1,000,000 cSt, far exceeding the capabilities of centrifugal pumps. This makes them essential for applications involving heavy oils, polymers, resins, and other thick fluids that challenge conventional pumps.
Precise flow control through variable speed operation allows operators to adjust output exactly to process requirements. The direct relationship between rotational speed and flow rate provides predictable, repeatable performance for metering applications.
The ability to handle corrosive fluids when constructed with appropriate materials expands application possibilities. Stainless steel, chemical-resistant alloys, and specialized coatings enable gear pumps to work with aggressive chemicals safely.
Compact size fits tight installation spaces common in mobile equipment and industrial machinery. The efficient design delivers high performance in minimal space, making gear pumps practical for applications with size constraints.
Self-lubricating operation when pumping lubricating fluids reduces external lubrication requirements. This feature simplifies maintenance and reduces operating costs in applications involving oils and other lubricating fluids.
FAQ
Q1: What viscosity range can gear pumps handle?
A1: Gear pumps excel with high viscosity fluids from 1 cSt to over 1,000,000 cSt. Internal gear pumps handle thicker fluids better than external designs due to their larger displacement chambers and looser tolerances. Very low viscosity fluids may cause excessive slip and reduced efficiency, while extremely thick fluids may require heating to reduce viscosity for optimal pumping performance.
Q2: How do I prevent gear pump damage from solids?
A2: Install upstream strainers to filter out particles larger than pump clearances, typically 75-100 microns for external gear pumps. Choose internal gear pumps for applications with small solids due to looser tolerances. Operate at lower pressures and speeds when handling fluids with abrasive content. Regular maintenance and inspection help detect wear before major damage occurs.
Q3: Can gear pumps run in reverse for emptying applications?
A3: Internal gear pumps offer bi-directional flow capability for both filling and emptying operations through inlet and outlet ports. External gear pumps typically operate in one direction only due to their design characteristics. Reversible operation requires compatible seals and bearing arrangements. Always check manufacturer specifications before implementing reverse operation to avoid damage.
Q4: What’s the difference between helical and spur gears in gear pumps?
A4: Spur gears are simpler and less expensive but create more pressure pulsations and noise during operation. Helical gears provide smoother flow with reduced noise and vibration due to gradual gear teeth engagement. Herringbone gears offer the smoothest operation but are more complex and costly to manufacture. Higher capacity applications typically benefit from helical or herringbone designs for better performance.
Q5: How often should gear pumps be serviced?
A5: Service intervals depend on operating conditions, fluid type, and duty cycle requirements. Monitor performance indicators like flow rate, pressure, and power consumption for early wear detection. Typical maintenance includes bearing lubrication, seal replacement, and clearance inspection. Clean, lubricating fluids allow longer service intervals than abrasive or corrosive media. Most industrial applications require inspection every 6-12 months with major service every 2-3 years.
Popular Gear Pumps at FabHeavyParts
1.
Hydraulic Gear Pump 093-7170 0937170 Fits for Caterpillar E110B E120 E120B
Condition: new, aftermarket
Part Number: 093-7170, 0937170
Applications: The Gear Pump fits for Caterpillar E110B, E120, E120B, E140, E180, E200B, E240, E240C, EL240B
Fitments: E180 EL180 HYDRAULIC EXCAVATORS 1RF00001-UP (MACHINE) POWERED BY 3204 ENGINE; E140 HYDRAULIC EXCAVATOR 1NF00001-09040 (MACHINE) POWERED BY 6D14 ENGINE; E240, EL240 HYDRAULIC EXCAVATORS 1FG00001-UP (MACHINE) POWERED BY 3304 ENGINE; E120 HYDRAULIC EXCAVATOR 1LF00001-UP (MACHINE) POWERED BY 6D14 ENGINE...
2.
Hydraulic Gear Pump AL16963 AL37752 0510615314 Fits For John Deere Tractor Serie 500 510 700 710
Condition: new, aftermarket
Part Number: AL16963, AL37752, 0510615314
Application: The Gear Pump fits for John Deere Tractor Serie 500, 510, 700, 710
Type: Single Pump
3.
Fits For Bobcat A20.5L36836 New Hydraulic Gear Pump 11T
Part Number: A20.5L36836, 6672051, 6672513, 550136836
Application Models: The Gear Pump is compatible with Bobcat Skid Steer 751 753 763 773 7753
Condition: new, aftermarket
4.
Part Number: 897147M95, 897147M94, 897146M94, 897147M92, 1662243M91, 3774617M91
Condition: new, aftermarket
Application: The Gear Pump fits for Massey Ferguson Tractor MF165, 168, 168S, 175, 178, 185, 188, 250, 265, 265S(2WD), 275, 285S, 290
Type: Single Pump
5.
Gear Pump RD809-77470 HRD80-77470 for Kubota Excavator KX080-3
Part Number: RD809-77470, HRD80-77470, RD80977470, HRD8077470
Applications: The Gear Pump fits for Kubota Excavator KX080-3
6.
Hydraulic Gear Pump 705-52-30210 Fits for Komatsu Forklift FD135-6
Part Number: 705-52-30210, 7055230210
Application: The Gear Pump fits for Komatsu Forklift: FD135-6
FAB Heavy Parts Can Help With Your Needs
Welcome to Fab Heavy Parts' online catalog, where you can explore a delightful array of Gear Pumps. We have a diverse selection to cater to your needs. Our knowledgeable parts team is at your disposal, ready to assist you every step of the way.