Centrifugal Pump Manufacturers and Suppliers

Centrifugal Pumps

A centrifugal pump features a simple design that includes a casing with a discharge valve housing an impeller with several blades attached to a rotating shaft powered by a mechanical drive. As the shaft turns, the impeller blades generate kinetic energy, which increases the pressure of the liquid passing through the casing. Once the pressure is raised, the fluid moves through the discharge valve and exits the pump. This process relies on centrifugal force combined with positive displacement to maintain operation.

This straightforward design allows centrifugal pumps to be integrated into various larger mechanical systems or engines, including those in automotive engines and water treatment facilities. Since centrifugal pumps handle a wide range of fluids, from water and oils to acids, their casings are commonly made from durable materials like stainless steel, cast iron, or aluminum. These pumps are also equipped with a weep hole, an opening located on the pump’s underside, designed to detect the initial signs of mechanical seal failure. The mechanical seal creates a barrier between the motor and the fluid, preventing leakage into the engine or motor. If the weep hole shows signs of leakage, the pump may require repair or replacement.

Centrifugal pumps can experience operational disruptions due to high pressure or excess oxygen, particularly in the form of air pockets that can form within the casing when the pump is idle and the casing is empty. This issue, known as cavitation, often requires the pump to be regularly primed or checked for air pockets to ensure smooth and continuous performance.

The History of Centrifugal Pumps

The earliest conceptual version of the centrifugal pump can be traced back to the Italian Renaissance, when engineer Francesco di Giorgio Martini described a mud lifting machine in a treatise published in 1475. However, the more modern and recognizable design, featuring straight vanes, did not come into existence until the 17th century, when Denis Papin created it. It wasn't until the 19th century that a significant advancement was made. In 1851, John Appold introduced his centrifugal pump design with a curved vane, a breakthrough that earned him a council medal at that year's Great Exhibition at the Crystal Palace. This curved vane design proved to be three times as efficient as the earlier straight vane pumps, marking a pivotal moment in the development of centrifugal pump technology and leaving a lasting impact on the industry.

A Note on Positive Displacement Pumps

Centrifugal pumps, while utilizing positive displacement in their operation, differ from other positive displacement pumps in that they also increase the speed of the liquid as it passes through the pump. In contrast, positive displacement pumps move the liquid at a consistent speed. Positive displacement pumps come in various configurations, including lobe, screw, peristaltic, and gear pumps.

A gear pump achieves positive displacement through the use of meshing gears. There are two main types of gear pumps: internal and external. An internal gear pump employs a combination of an internal gear and an external gear spur, while an external gear pump uses two external gear spurs. The fluid is moved at a constant rate with each revolution of the gears. Gear pumps are commonly used in hydraulic fluid power applications.

Design of Centrifugal Pumps

Most vehicles produced in the United States during the 20th century rely on centrifugal water pumps to circulate water through the engine. The performance of the pump, and subsequently the engine, can sometimes be enhanced by modifying the impeller to increase the flow rate.

Centrifugal pumps typically differentiate themselves by altering either the impeller or the discharge apparatus. The curvature and depth of the impeller vanes or blades play a significant role in the pump's performance. Additionally, impellers can be designed as either open or closed. In a closed impeller, a plate or other enclosure is attached to the blades, which can increase the flow rate in certain applications, depending on the type of fluid being pumped.

The size of the discharge apparatus and the speed of the shaft also affect the flow rate. However, it is crucial that any modifications made to the pump do not cause an excessive increase in "head," or pressure within the system. Head is measured in pounds per square inch (PSI) and refers to the force exerted by the fluid within the pump.

Centrifugal Pumps Images, Diagrams and Visual Concepts

Types of Centrifugal Pumps and Applications

Axial Flow Pumps
These pumps feature a vertical shaft connected to a perpendicular impeller. The impeller vanes lift the liquid upward, moving it in an axial direction. A jet pump helps increase suction, enhancing the centrifugal pump's operation, while a submersible pump is installed underground. Submersible pumps are continuously submerged in liquid, ensuring that they are self-priming—air pockets rarely form in the suction line since the pump is always circulating water or another liquid.

Submersible Pumps
While most pumps operate mechanically, submersible pumps can also be powered by hydraulic motors or electricity. These pumps have power cords encased in durable, waterproof rubber coverings. Due to their maintenance challenges, electric submersible pumps tend to be smaller, often 12 volts, and are used for specific tasks like pumping water from a flooded area. Sometimes referred to as sump pumps, they are placed on a floating rig with an outbound discharge hose to gradually pump out unwanted water.

Chemical Pumps
These pumps are designed to handle abrasive fluids such as bleach, resin, acid, and other corrosive, toxic materials. They're commonly used in industrial settings. Well pumps , on the other hand, are used to extract water from underground sources to a higher location within buildings, often in conjunction with pressure tanks for large structures like apartment buildings.

Trash Pumps
Centrifugal trash pumps are designed for liquids contaminated with debris like twigs, small rocks, sand, and other materials. These pumps are typically used in wastewater treatment and sewage operations. Trash pumps can process thousands of gallons per minute, handling thick, viscous liquids thanks to large discharge openings and deep impeller vanes. Variants include semi-trash pumps and dewatering pumps, which handle non-hazardous water with particles up to 0.25 inches in diameter. Some dewatering pumps are fully submersible and can operate in any position, even upside down.

Close-Coupled Pumps
These pumps are directly connected to a power unit, without the need for additional gearing or shafting.

Double Suction Pumps
A type of radial flow pump where fluid enters the impeller from both sides. Due to the shaft extension into the suction passage, these pumps are typically used for clear liquids only.

Mixed Flow Pumps
Featuring wide unblocked passageways, mixed flow pumps combine features of both radial and axial flow pumps. They generate pressure through a mix of centrifugal force and impeller vane lift.

Multistage Pumps
These pumps consist of two or more pumps in series, discharging into each other. Each pump stage contributes to the total head, the sum of the heads developed by each impeller. A common shaft with several impellers builds pressure in stages.

Radial Flow Pumps
In radial flow pumps, liquid enters the impeller center and is forced out along the blades at a 90-degree angle to the pump shaft. These pumps develop pressure using centrifugal force.

Single-End Suction Pumps
A type of radial flow pump where fluid enters from one side of the impeller, and the shaft doesn't extend into the suction passage. These pumps are ideal for applications with large solids, such as rags or trash, that might clog other types of pumps.

Two-Speed Centrifugal Pumps
These pumps feature a two-speed motor that allows the shaft and impeller to operate at two different rpm levels, providing variable pump capacity.

Vertical Cantilever Pumps
Designed to keep the casing and impeller submerged in the pumpage for priming, these pumps ensure that the support bearings for the rotating element remain in a dry environment.

Vertical Pumps
Vertical centrifugal pumps use mechanical energy to create kinetic energy, increasing the pressure of a liquid as it moves upward through a pipe.

Vortex Pumps
These pumps are designed with recessed impellers within the volute. Although inefficient, vortex pumps are useful in applications that require handling excessive solids.

Maintenance of a Centrifugal Pump

While a certain level of increased pressure is required for a pump to operate effectively, excessive head pressure can disrupt its balance and cause damage. In extreme cases, too much pressure may cause the pump to detach from its shock mounts, leading to potential harm to the engine or nearby components. To avoid such issues, it’s important for pump owners to regularly prime the pump to prevent cavitation and ensure that they aren't attempting to push too much liquid through the system too quickly. Operating the pump with an excessively fast motor can also lead to the buildup of harmful head pressure, further damaging the pump.

Frequent cavitation can also cause lasting damage to the pump’s internal components. The impeller blades may become pitted when air pockets explode under pressure. Regular priming of the pump can help minimize cavitation, but over time, some level of cavitation is likely to occur during the pump’s lifespan.

Things to Consider Regarding Manufacturers

Purpose and Size of Pumps
Centrifugal pumps are produced by various manufacturers for a wide range of applications, and their size and power generally increase with the scale of the intended use. Larger, industrial-grade centrifugal pumps can achieve flow rates of up to 40,000 gallons per minute, suitable for heavy-duty applications, while smaller pumps are designed for less demanding tasks, such as in vehicles or residential well pumps. The need for such a high flow rate wouldn’t apply in a smaller-scale operation.

Manufacturers are exploring alternatives to traditional metal materials for pump seals, using thermoplastics and fluorocarbons, which offer improved corrosion resistance and potentially extend pump life. While stainless steel, cast iron, and aluminum remain common for exterior casings, plastic is sometimes used depending on the application.

The use of jet pumps has diminished in recent years as manufacturers have developed pumps that provide adequate suction without additional support. However, depending on the fluid’s viscosity and the amount of debris, a jet pump may still be necessary in certain circumstances.

Pump Application
When choosing the right manufacturer for their needs, clients must clearly define the pump's intended application. For instance, a client installing drainage pumps for low-lying properties will have different requirements than one looking to modify water pumps for improved automotive engine performance. Additionally, understanding the type and purity of the fluid the pump will handle is crucial. Drainage pumps typically deal with water containing debris or particulate matter, while pumps for automotive engines often handle cleaner fluids with minimal contaminants. The condition of the fluid directly impacts the selection of the appropriate pump.

Batch Size of Pumps
Many manufacturers prefer producing large production batches, known as “mill runs,” as this helps reduce overhead costs and ensures a steady revenue stream. Clients looking to design a new or improved centrifugal pump should start with prototypes. These prototypes are essential for testing, allowing the identification of any design flaws or unexpected issues before mass production begins. If manufacturers do not have a dedicated department for prototype production, they often recommend skilled machinists or fabricators to assist in this phase.

Centrifugal Pumps Terms

Air Bound
A situation in which a centrifugal pump becomes so filled with air that it can no longer create a vacuum, preventing water from entering the pump.

Atmospheric Pressure
The force applied by the atmosphere to the Earth's surface. The standard atmospheric pressure is 14.7 lbs per square inch and affects pump operations.

Capacity
The measure of how much water a pump can process, typically expressed in gallons per minute (gpm) or gallons per hour (gph).

Cavitation
An undesirable condition where vacuum pockets form within the pump. These air pockets implode under pressure, causing pitting on the impeller and volute surfaces.

Centrifugal Force
The force that drives a substance away from its center of rotation.

Check Valve
A device in the discharge or suction line that permits flow in one direction only, preventing reverse flow and isolating the material being pumped.

Dewatering
The process of removing unwanted water, which can be either clear or dirty, but not hazardous.

Diffuser
A stationary component, like a volute, that houses the impeller and helps generate higher pressure heads.

Discharge Hose
A flexible hose that transports the water discharged by the pump.

Discharge Port
Also known as the "outlet," this is where the discharge pipe or hose connects to the pump.

Drain Plugs
Detachable plugs used for draining water from the pump when it’s not in use.

Dynamic
Relating to motion, as opposed to static, which is related to weight.

Dynamic Head
The head or pressure force against which the pump operates.

Dynamic Suction Head
Also known as “total suction head,” it’s the combination of static suction lift and suction friction loss in the suction line.

Effluent
Partially or completely treated wastewater or liquid that flows from a treatment unit.

Flapper Valve
A rubber valve molded around a steel weight that prevents the water from entering or exiting the pump at improper times.

Flow Rate
The amount of water pumped, typically measured in gallons per minute (gpm) or gallons per hour (gph).

Head
The pressure or force exerted by a fluid in a hydraulic system, measured in pounds per square inch (psi) or feet of water, considering gravity and friction losses or gains.

Impeller
A rotating disk with blades attached to the shaft that generates centrifugal force within the pump casing.

Impeller Eye
The center of the impeller where fluid enters.

Impeller Vanes
Blades located on the impeller that direct fluid from the eye to the outer edges of the impeller.

Intake
The rate at which fluid flows into a pump.

Mechanical Seal
A device that prevents water from entering the motor or engine of the pump by forming a seal between the pump and motor.

Net Positive Suction Head Available (NPSHA)
A measure of the absolute pressure of the liquid at the pump's inlet.

Prime
The process of removing air from the influent line to start fluid flow. This can be done by manually filling the volute or turning the pump on.

Pump Housing
The casing or body of the pump, typically made of plastic, cast-iron, stainless steel, or aluminum.

Shock Mounts
Rubber devices used to dampen vibration and prevent the pump from moving or damaging other equipment.

Static
Relating to weight, in contrast to dynamic motion.

Strainer Basket
A plastic mesh basket that catches debris before it can reach the impeller, preventing damage.

Strainer Pot
The housing for the strainer basket, located on the influent side of the pump, also serving as a priming chamber.

Suction Hose
A reinforced hose through which fluid is drawn into the pump.

Vane Passing Syndrome
A type of cavitation caused by impeller size limitations or low clearance in the cutwater.

Vent
The process of releasing air or gas from a system to prevent dry running of the seal faces in pumps.

Viscosity
The thickness of a liquid and its resistance to flow. For example, motor oil has a higher viscosity than water and flows more slowly.

Volute
A spiral-shaped casing in which the impeller rotates, helping convert the kinetic energy of the fluid into pressure head.

Vortexing Liquid
A "whirlpool effect" that can draw air into the suction line of the pump, causing cavitation.

Weep Hole
A small opening on the underside of the pump to detect leaks before water enters the engine's oil sump.