Top 9 Factors to Consider Before Selecting a Gear Pump

Gear pumps play a crucial role in various manufacturing processes, from adding flavors to beverages and mixing cleaning chemicals to filling cosmetic bottles. These positive displacement pumps deliver a consistent amount of fluid with each rotation, making them ideal for precise metering tasks across many industries.

Common Applications for Gear Pumps:

• Chemical and Petrochemical Industries: For adding precise amounts of chemicals to flow processes
• Food and Beverage: In packaging and dispensing
• Paint Industry: To inject paint pigments accurately
• Road Construction: For metering asphalt onto roadways
• Food Manufacturing: To meter viscous materials in products like sausages and bologna

Consider these nine factors to determine if a gear pump is appropriate for your needs:

1. Metering Accuracy: Ensure your accuracy requirements are achievable and cost-effective. Extreme accuracy needs may eliminate economical options.
2. Operating Conditions: Assess all potential conditions under which the pump will operate. Overlooking these can lead to costly adjustments later.
3. Differential Pressure: Minimize pressure to reduce “slip” by using short, adequately sized suction and discharge lines. Ensure there is sufficient Net Positive Suction Head Available (NPSHA) to avoid cavitation. Lower pump speeds may be necessary for high viscosities.
4. Slow Speeds: Be cautious with applications requiring very slow speeds, as this can increase the proportion of “slip” and affect metering accuracy.
5. Design Considerations: When using a gear pump for metering, sometimes it’s beneficial to avoid extra clearances to enhance accuracy, even if it means higher drive horsepower.
6. Wear and Tear: Consider the long-term effects of abrasive or corrosive materials on the pump’s internal components.
7. High Temperatures: Ensure the pump can handle elevated temperatures and manage “slip” effectively. High-temperature applications often involve low fluid viscosities, which need careful consideration to avoid performance issues.
8. Drive Accuracy: The pump’s accuracy is limited by the precision of the drive mechanism. Ensure the drive provides consistent speed variation and repeatability.
9. Mounting and Piping: Follow recommended practices for mounting and piping to prevent strains that can affect the pump’s performance.

When shouldn’t you use a gear pump? 

While gear pumps are versatile, they aren't suitable for every application. Internal gear pumps are not well-suited for handling large solids. Due to their tight tolerances, these pumps are prone to damage from larger particles. While they can manage some small, suspended solids in abrasive fluids, this can lead to increased wear and reduced performance over time.

Additionally, internal gear pumps may become less efficient with lower fluid viscosities. When dealing with low-viscosity fluids and high discharge pressures, the fluid can "slip" through the pump's machined clearances, causing it to recirculate from the discharge side back to the suction side.

This product slip generally affects efficiency but can pose significant issues with materials that harden upon standing, such as chocolate and adhesives. In such cases, it may necessitate a suckback to address the problem.

If you think a gear pump could be beneficial for your application, reach out to us for assistance. We offer gear pumps from top manufacturers like Gorman Rupp and provide expert advice, sizing, selection, and precision repairs to ensure optimal performance.

Expert Assistance

Professional Pump is here and ready to support you with your positive displacement pumps and internal gear pumps. We provide a complete service and repair team who will fix pumps back to OEM standards. 

If you need help selecting the right pump for your application, ask us about it!  Our company provides pumps, valves, parts, and service to customers in Michigan and NW Ohio. Professional Pump can also design and build customized skid systems nationwide.