What is Deadheading in Centrifugal Pumps?
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Pump deadheading occurs when a centrifugal pump runs with no flow due to a closed discharge valve or blockage. This anomaly can have severe consequences, leading to overheating, seal damage, system overpressure, or even explosion in extreme circumstances, making it essential to have precautions and procedures in place to reduce the possibility of pump deadheading for optimal system performance and operation. At Springer Parts, we provide a variety of high-quality centrifugal pump replacement parts, including mechanical seals and impellers, for solutions to prevent deadheading in your pump systems.
How Deadheading Affects Centrifugal Pump Performance
If the discharge valve is closed while the pump is running, it can cause the flow to stop entirely. While system supervisors may not recognize the issue immediately, pump deadheading can lead to significant challenges that reduce safety and operational performance. Deadheading in pump systems has adverse effects on the system and its components, such as:- Fluid Churning and Heat Buildup: Fluid recirculation can lead to rapid temperature rise and vaporization, damaging seals and critical mechanical components.
- Risk of Overpressure: In reduced flow or no-flow conditions, the unused energy causes heading and pressure buildup, leading to seal failure or explosion.
- Seal and Bearing Damage: Due to heat and vaporization, mechanical seals and bushings can crack or erode.
- Pump and Motor Wear: Without fluid cooling, the internal pump components will wear prematurely, and motors may overheat from energy without a load.
Why is Pump Deadheading Hard to Detect?
When deadheading occurs, it can be challenging to detect because of the slight changes the anomaly causes within the pump system. If the pump casing remains full, flow sensors will fail to recognize no-flow conditions. Another method for detection utilizes motor current monitoring, but the motor current may not drop significantly during deadheading, as the current will remain nearly constant until 50% of the motor load.Better Monitoring Techniques to Assess Deadheading in Pumps
Prioritizing the detection of deadheading in pumps can reduce the risk of damage and pump failure. With the proper precautions, it is easier can be easier to determine the presence of pump deadheading by:- Using input power monitoring for sensitivity to load changes
- Installing temperature sensors on the casing or discharge pipe
- Adding flow meters or pressure sensors to detect flow stoppages
Who is at Risk for Pump Deadheading and When Does it Happen?
Pump deadheading can be detrimental and potentially damaging to pump systems, leading to pump failure and even explosion if not adequately addressed. There are a range of common causes for pump deadheading, including closed or blocked discharge valves, piping clogs or control faults, and running intentional test procedures without system bypassing that can significantly affect the performance and operation of your pumps. While small pumps may tolerate short deadheading, industrial pumps can fail in seconds; it is essential to safeguard your systems from potential issues.Protecting Your Centrifugal Pump from Deadheading Challenges
There are various precautions you can take to minimize deadheading in pump systems for optimal performance and efficiency. In addition to conducting routine maintenance, such as inspecting seals, bearings, and motor load patterns, incorporating monitoring devices and reinstallation of components can reduce pump deadheading by leveraging flow capabilities, with solutions including:- Installing Recirculation Lines and Bypass Valves: These components will allow minimal flow even when discharge is shut off.
- Utilizing Automatic Flow Control Devices: Throttle and orifice plates can be used within a pump system to maintain safe downstream flow.
- Integrating Motor Protection Alarms: By promoting early detection with low-power relays, these components combine with temperature and vibration sensors to trigger alarms or pump shutdown.