A charge pump is usually a centrifugal or positive displacement pump used to “charge” or feed another pump (like a high-pressure pump) with the necessary inlet pressure to avoid cavitation. It's a specialized type of pump used to maintain pressure and flow in fluid systems, especially in applications requiring a consistent supply to downstream components. In simple terms, charge pumps “feed” other pumps or systems—ensuring there’s always a stable volume of fluid available, often under pressure.
In fluid handling equipment, a charge pump helps prevent cavitation, maintain system efficiency, and improve equipment longevity. These pumps are essential in setups like hydraulic systems, mud pumping operations, and horizontal directional drilling (HDD), where continuous, pressurized fluid is a must. Whether you’re working in industrial processing, oil and gas, or construction dewatering, charge pumps play a vital supporting role that keeps everything running smoothly.
How Does a Charge Pump Work?
Unlike pumps that move fluids for end use, a charge pump primes or maintains conditions for other system pumps. Its core function is to supply fluid at the right pressure and flow rate so that the main pump—often a mud pump, centrifugal pump, or positive displacement pump—doesn’t run dry or suffer from suction-related problems.
Charge Pump Flow:
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Fluid Source – Charge pump pulls fluid from a tank or reservoir.
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Pressurization – Pump increases fluid pressure to meet system requirements.
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System Feed – Fluid is fed into another pump or into a pressurized loop.
Because they’re part of closed-loop systems, charge pumps often support fluid handling in cooling, hydraulic, or HDD operations—making them indispensable in precision-demanding industrial environments.
How Does a Charge Pump Compare to Other Pump Types?
Centrifugal pumps move high volumes of clean fluid with moderate pressure. Charge pumps feed systems like centrifugal pumps to prevent cavitation.
✅ Use centrifugal pumps for high-flow tasks.
✅ Use charge pumps to supply steady pressure to downstream equipment.
Diaphragm pumps are chemically resistant and can handle aggressive, viscous fluids. Charge pumps maintain pressure, not chemistry.
✅ Use diaphragm pumps for dosing or chemical transfer.
✅ Use charge pumps to support systems that need fluid pre-feed.
Positive displacement pumps deliver exact volumes and handle thick fluids. Charge pumps ensure those pumps always have fluid to draw.
✅ Use PD pumps for accurate flow.
✅ Use charge pumps to prevent dry-run scenarios.
Other relevant comparisons:
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Grinder Pumps cut and transport solids in sewage—different than pressure support.
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Peristaltic Pumps deliver sanitary or abrasive fluid flow, often in metering applications.
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Trash Pumps move debris-laden water quickly but aren’t suited for pressure feeding.
Read our blog for more information on charge pumps compared to other common pump types.
What Are Common Applications of Charge Pumps?
Charge pumps are critical to a range of fluid processing equipment across industries. Common applications include:
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Mud Circulation in HDD: In horizontal directional drilling, charge pumps feed drilling fluids to mud pumps, preventing pressure drops or flow interruption.
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Hydraulic Systems: Keep hydraulic circuits pressurized to improve response time and prevent air ingestion.
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Water and Wastewater Processing: Supply pressurized flow to treatment equipment or booster systems.
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Well Pump Replacement Systems: In remote areas, charge pumps stabilize pressure in systems where wells feed into surface or storage tanks.
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Industrial Mixing & Dosing: Ensure flow consistency when supplying process lines or secondary metering systems.
In these roles, charge pumps are often used alongside mud pumps, trash pumps, grinder pumps, and centrifugal pumps, forming a complete fluid handling solution.
How Are Charge Pumps Used in Fluid Handling Systems?
As part of a broader fluid handling solution, charge pumps serve as a backbone component. Their purpose is simple—but crucial: to keep other pumps safe, stable, and productive.
In complex operations like HDD or refinery loops, charge pumps provide constant fluid availability to surface pumps and booster systems. They can also work in tandem with peristaltic or diaphragm pumps in metering or chemically aggressive environments.
In wastewater, they’re often used before grinder pumps to ensure the system remains primed and avoids dry starts.
How do you Choose the Right Charge Pump?
Selecting a charge pump depends on:
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Flow Rate Needs – Match downstream pump requirements.
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Pressure Head – Ensure the system stays primed under pressure.
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Fluid Type – Choose material compatibility for corrosive or abrasive fluids.
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Pump Integration – Consider compatibility with centrifugal or mud pumps.
Some applications may benefit more from:
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Peristaltic Pumps for sanitary or dosing use
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Diaphragm Pumps for chemical resilience
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Grinder Pumps in systems with solids
If the system is part of a well pump replacement, tank pressurization, or fluid blending setup, a charge pump is likely the best fit.
What Questions are Frequently Asked About Charge Pumps?
What is a charge pump?
A charge pump is a centrifugal or positive displacement pump that supplies pressurized fluid to a larger downstream pump — typically to prevent cavitation, maintain suction-side pressure, and ensure consistent flow. Charge pumps are common in mud pumping, hydraulic systems, and horizontal directional drilling, where the main pump can't be allowed to run dry or starve for fluid.
Can a charge pump run dry?
No — charge pumps should never run dry. A dry-running charge pump can cavitate within seconds, damaging the impeller and mechanical seal. Because charge pumps exist specifically to prevent the main pump from starving, the charge pump itself needs a reliable fluid source, an unobstructed suction path, and proper inlet pressure to avoid the same failure mode it's designed to prevent.
Where are charge pumps used?
Charge pumps are used wherever a main pump needs guaranteed inlet conditions. Common applications include mud pump systems for oil & gas drilling and horizontal directional drilling (HDD), hydraulic circuits where consistent inlet pressure matters, boiler feedwater systems, multi-stage industrial pump setups, and wastewater systems that feed grinder or transfer pumps. The pattern is always the same: protect the downstream pump from cavitation by guaranteeing what it pulls from.
How is a charge pump different from a booster pump?
Both pumps add pressure to a system, but they serve different roles. A charge pump sits upstream of another pump and exists to feed it — making sure the downstream pump always has enough inlet pressure to operate safely. A booster pump sits in the delivery line and increases pressure to the end user (a building, a fixture, a remote tank). Charge pumps protect equipment; booster pumps move fluid further.
Do I need a charge pump in my horizontal directional drilling (HDD) system?
Yes — a charge pump is essentially required in any HDD system using a piston or plunger mud pump. The mud pump needs steady, positive inlet pressure to avoid cavitation when pumping abrasive drilling fluid. Without a charge pump, you risk impeller damage, premature seal failure, and unscheduled downtime — all of which cost more than the charge pump itself in a single incident.
