Suctions bells are important enough that we include a section in our popular Installation and Care Guide, about the importance of the equipment and how to properly size it.
Here are the primary reasons why a bell strainer is critical in these applications:
1. Prevents Debris from Entering the Pump
Open water sources typically contain floating debris, sediment, aquatic vegetation, and occasionally trash or other foreign materials. A bell strainer prevents large solids from entering the suction line, where they could cause:
- Clogging of the pump impeller or volute
- Damage to wear rings and seals
- Blockages in downstream piping or irrigation equipment
- Abrasive wear that reduces pump life
By stopping large objects at the intake, the bell strainer serves as the first line of defense against pump damage.
2. Reduces Suction Losses and Maintains Flow
A bell strainer is specifically designed with a wide opening and large surface area relative to the suction pipe. This design minimizes pressure losses at the pump suction and helps maintain adequate flow. Unlike flat or undersized screens that can easily clog or restrict water intake, a properly sized bell strainer:
- Ensures smooth, unrestricted water entry
- Reduces the risk of suction cavitation, which can severely damage pump components
- Helps maintain consistent system pressure and flow rates essential for irrigation
3. Extends the Service Life of the Pump
By preventing large debris and minimizing suction strain, a bell strainer reduces mechanical wear on the pump’s internal components. This protection directly contributes to:
- Fewer maintenance issues over time
- Reduced downtime due to repairs or cleaning
- Longer overall service life of the pump and motor
This is particularly important in agricultural settings where consistent water delivery is critical for crop health and productivity.
4. Protects Downstream Irrigation Equipment
Modern irrigation systems often include filtration units, pressure regulators, valves, and emitters. Allowing debris into the suction line can lead to:
- Clogged filters and screens
- Plugged drip emitters or spray nozzles
- Malfunctioning valves and regulators
By stopping debris at the source, a bell strainer helps protect the entire system and reduces the frequency of maintenance on downstream components.
5. Supports Reliable and Efficient Operation
Uninterrupted water supply is essential for irrigation scheduling and crop success. A blocked or damaged pump can halt operations, leading to missed watering windows and potential crop stress. The bell strainer helps ensure:
- Continuous, trouble-free operation
- Reduced risk of emergency shutdowns or costly repairs
- Peace of mind for operators managing critical irrigation tasks
6. Vortexing Mitigation
One more advantage of a bell inlet is its larger entrance diameter, which reduces the minimum required submergence and decreases the risk of vortex formation: keeping flow smooth and preventing air entrainment. We’ll be discussing minimum submergence and vortexing in the next Tuesday Tip.
Recommended Best Practices for Bell Strainers
- Sizing: The open area of the strainer should be at least four to six times the cross-sectional area of the suction pipe to avoid excessive restriction.
- Installation: Position the strainer at the correct depth to avoid floating debris near the surface and sediment from the bottom.
- Maintenance: Inspect and clean the strainer regularly to ensure it remains free-flowing and effective.
