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What Is Deadheading (Pump)? | Process Engineering Glossary
What Is Deadheading (Pump)?
Deadheading is a condition in which a centrifugal pump operates against a fully closed discharge valve or blocked discharge line, producing zero flow while the pump continues running at its shutoff head. Because a centrifugal pump continues converting mechanical energy into fluid energy even with no flow path available, that energy has nowhere to go except into heating the small volume of liquid trapped within the pump casing, which can rapidly reach damaging temperatures.
Deadheading can occur unintentionally, such as from an operator error closing a discharge valve without stopping the pump, or intentionally in rare testing scenarios, but in either case, extended deadhead operation risks significant pump damage and is generally protected against through minimum flow protection systems.
Applications of Deadheading
Minimum Flow Protection System Design
Pumps in services prone to potential deadheading are commonly protected with minimum flow bypass systems that automatically recirculate a portion of discharge flow if main flow drops too low.
Pump Curve Shutoff Head Evaluation
A pump’s shutoff head, the head developed at zero flow, is a standard data point on its pump curve, directly relevant to understanding deadhead conditions and appropriate relief valve settings on the discharge side.
Operating Procedure and Interlock Design
Operating procedures and safety interlocks are often specifically designed to prevent operators from closing a discharge valve while a pump remains running, directly addressing deadheading risk.
Benefits of Knowing Deadheading
Prevents costly pump damage from overheating. Understanding deadheading risk supports designing minimum flow protection that prevents the rapid temperature rise this condition can cause.
Clarifies the value of shutoff head data. Recognizing why shutoff head matters supports better interpretation of pump curve data during design and troubleshooting.
Informs effective interlock and procedure design. Understanding common deadheading scenarios supports designing operating procedures and interlocks that specifically prevent this avoidable failure mode.
Limitations to Consider
Minimum flow protection adds system complexity and cost. Bypass and recirculation systems designed to prevent deadheading add piping, valves, and control complexity beyond a simpler system design.
Temperature rise can occur very quickly. Because the trapped liquid volume in a pump casing is small, temperature rise during deadhead operation can occur faster than an operator might expect, limiting response time.
Protection systems require reliable, tested operation. Minimum flow protection systems themselves need to be reliable and periodically tested, since a failed protection system provides a false sense of security.
Deadheading FAQ
How does deadheading relate to dry running as a distinct pump failure mode?
While deadheading involves a pump running against a closed discharge with liquid still present in the casing, dry running describes a pump operating with insufficient or no liquid at all, both damaging but through different mechanisms.
Why is a pump’s shutoff head relevant to deadheading conditions?
A pump’s shutoff head, part of its overall pump curve characteristics, determines the maximum pressure the pump develops during a deadhead condition, directly informing appropriate relief valve set pressure selection on the discharge side, sized with correct line sizing in mind.
How does deadheading connect to closed-loop control and low-low level trip protection?
Minimum flow protection relies on closed-loop control to detect and respond to low-flow conditions, working alongside safeguards like a low-low level trip as part of comprehensive pump protection, relevant also to vapor lock and proper pump priming at startup.
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