How 12 Different Fluid Transfer Pumps Works

Use this fluid-transfer pump guide to compare how common pump styles move liquid, what each style is known for, and which details to check before choosing a replacement pump.

How the Centrifugal Pump Works

• Liquid enters the inlet port through gravity or priming and moves toward the center of the impeller.
• The rotating impeller uses centrifugal force to add velocity as liquid moves from the blade edges into the volute casing.
• The volute configuration converts velocity energy into static pressure or available pump head as liquid leaves the discharge port.
• Source features: high-volume flow, smooth non-pulsating delivery, low maintenance, few moving parts, easy disassembly, and low power consumption for moving large liquid volumes.

How the Diaphragm Pump Works

• As the piston diaphragm pulls away from the housing, the cavity increases in size and creates a vacuum that draws liquid through the one-way inlet valve.
• As the diaphragm pushes toward the housing, the cavity decreases in size and forces liquid through the one-way outlet valve.
• Source features: dry-running operation, self-priming lift up to 15 feet under ideal conditions, and self-adjusting operation for air-operated diaphragm pumps as viscosity changes.

How the Flexible Impeller Pump Works

• As flexible impeller blades leave the cam, cavities increase in size and create a vacuum that draws in liquid.
• Once the blades clear the inlet port, liquid is captured between the blades and housing.
• As the blades contact the cam and bend, the cavity is reduced and liquid is forced out the discharge.
• Source features: self-priming from a dry or wet start, lift up to 15 feet when wet, and low-shear smooth pumping action for liquids of low to high viscosity.

How the Plunger Pump Works

• As the crankshaft rotates, the connecting rod pulls the plunger back from the liquid chamber in the manifold, increasing chamber size.
• That movement creates a vacuum that draws liquid through the inlet valve.
• As rotation continues, the connecting rod pushes the plunger toward the liquid chamber, reducing chamber size and forcing liquid out through the discharge valve.
• Source features: high pressure up to 15,000 psi, clean non-abrasive liquid requirements, ceramic plungers, and an oil-filled crankcase for long operating life.

How the External Gear Pump Works

• As gears separate on the inlet side, cavities form between gear teeth and create a vacuum that draws in liquid.
• Once the teeth clear the inlet port, liquid is captured between the gear teeth and housing.
• As the teeth mesh, liquid is squeezed from the cavity and forced out the discharge port.
• Source features: smooth repeatable metering flow for thin to viscous liquids, pressure up to 500 psi, and clean non-abrasive liquid requirements.

How the Vane Pump Works

• Centrifugal force, springs, or both keep the blades in contact with the housing as each blade leaves the upper eccentric area.
• Liquid is drawn in as the cavity between the blades and housing increases during rotary motion.
• After liquid is captured, the blades move into the eccentric portion of the housing and force liquid out the discharge.
• Source features: self-priming lift up to 3 feet with higher lifts possible on some models, thin to medium viscosity handling, and simple construction with few moving parts.

How the Lobe Pump Works

• Counter-rotating rotors create a partial vacuum that draws liquid smoothly into the pump chamber.
• As the rotors revolve, liquid is captured between rotor cavities and the outer housing.
• Liquid is forced out the discharge as the rotors mesh and eliminate the cavities occupied by the liquid.
• Source features: improved efficiency, longer sealing surfaces, gentle low-shear solids handling, abrasive handling, and wide viscosity range from 1 to 1,000,000 centipoise.

How the Air Operated Diaphragm Pump Works

• Compressed air powers the piston, enlarging one cavity and drawing in liquid through a check valve.
• At the same time, the opposite cavity is compressed and forces liquid out through a one-way check valve toward the discharge.
• The cycle repeats as compressed air redirects the piston.
• Source features: dry-running operation, dead-head stall behavior when discharge is blocked, and self-priming lift up to 20 feet under ideal conditions.

How the Roller Pump Works

• Centrifugal force moves each roller against the housing as the roller leaves the upper eccentric area.
• Liquid is drawn in as the cavity between the rollers and housing increases during rotary motion.
• As rollers are pushed back into their slots, cavity size is reduced and liquid is forced out the discharge.
• Source features: abrasive handling, pressure up to 300 psi, and simple construction with few moving parts.

How the Peristaltic Pump Works

• As rollers compress the hose and move away from the inlet, a vacuum draws in liquid.
• The rollers capture liquid between pinched areas of the tube and move it toward the discharge.
• The front roller opens the captured area while the back roller pushes liquid out of the discharge.
• Source features: no liquid contact except with the hose, self-priming lift up to 25 feet, and handling for viscous, corrosive, abrasive, and high-purity solutions.

How the Regenerative Turbine Pump Works

• Liquid enters the suction port and is moved forward by impeller blades in an orderly circular flow around the housing.
• The side-channel liquid flow occurs many times during one revolution.
• The source describes discharge pressure as 10 times or more than similar-diameter impellers turning the same speed in a centrifugal pump.
• Source features: high head with low flow, continuous-duty operation, compact size compared with multistage centrifugals delivering the same flow and head, and entrained-air handling up to 20%.

How the Progressing Cavity Pump Works

• Liquid is drawn into the pump suction as the corkscrew-shaped rotor revolves within the rubber stator.
• Liquid is captured in the cavity between the rotor and stator.
• The cavity travels toward the discharge and delivers contents as it reduces in size.
• Source features: abrasive or viscous liquid handling, low-shear pumping for shear-sensitive and solid-entrained liquids, and pressure up to 600 psi.

Next step on CLR Marine

Use onsite search, product filters, and product detail pages to compare pump style, liquid type, priming needs, flow, pressure, lift, voltage, port size, SKU, MPN, and manufacturer model before ordering.

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