Centrifugal Pump Priming System using a Self-Priming Driven Pump
Here’s a description of a system for priming a centrifugal pump using a priming pump driven from the centrifugal pump itself:
Components:
- Centrifugal Pump: The main pump that needs to be primed.
- Self-Priming Driven Pump: A smaller pump, often a vane pump, designed to be self-priming. This pump will be driven by the shaft of the centrifugal pump.
- Drive Mechanism: A pulley or gear arrangement that connects the shaft of the centrifugal pump to the shaft of the driven pump. This ensures the driven pump operates whenever the main pump is running.
- Check Valve (Optional): A one-way valve installed on the discharge line of the driven pump.
- Common Discharge Manifold: A pipe connecting the discharge of the driven pump to the inlet of the centrifugal pump.
- Vent Valve: A valve installed on the highest point of the centrifugal pump casing to allow air to escape during priming.
Operation:
- Initial State: The centrifugal pump is filled with air, and the vent valve is open.
- Start-Up: The centrifugal pump is started. This simultaneously starts the driven pump due to the drive mechanism.
- Self-Priming of Driven Pump: The self-priming driven pump utilizes its own design features (e.g., vanes, internal geometry) to evacuate air from its inlet and itself.
- Fluid Transfer: The driven pump draws liquid from the suction source (e.g., reservoir, tank) and discharges it through the common discharge manifold.
- Centrifugal Pump Filling: The liquid from the driven pump fills the casing of the centrifugal pump, displacing air through the open vent valve.
- Vent Valve Closure: Once the centrifugal pump casing is filled with liquid and air is expelled, the vent valve is closed.
- Priming Complete: With the centrifugal pump filled with liquid and the vent valve closed, the system is now primed, and the centrifugal pump can operate efficiently.
Optional Check Valve:
- A check valve installed on the discharge line of the driven pump can prevent backflow from the centrifugal pump into the driven pump when the centrifugal pump is not operating.
Benefits:
- Simple and Reliable: This system utilizes readily available components and is relatively simple to implement.
- Automatic Operation: The priming process is automatic as long as the centrifugal pump is running.
- Reduced Manual Intervention: Eliminates the need for a separate priming procedure or external source for priming.
Limitations:
- Head Limitations: The driven pump needs to have sufficient suction lift capability to draw liquid from the source and overcome any elevation difference.
- Power Consumption: Running the driven pump adds a small load to the centrifugal pump motor, increasing overall power consumption during priming.
Note: This is a general description, and specific implementations may vary depending on the pump sizes, system requirements, and safety considerations. Always refer to manufacturer’s recommendations and safety protocols when working with pump systems.