Difference Between Centrifugal Pump and Reciprocating Pump Explained

Pumps come in several types and choice of a suitable pump holds the key to operational success. In this blog, we will explore the difference between Centrifugal pumps and reciprocating pumps as well as their advantages and applications.

What are Centrifugal Pumps?

Centrifugal pumps operate on the principle of centrifugal force, which is generated by the rapid rotation of an impeller or an enclosed set of vanes within the pump. This rotation creates a low-pressure area at the centre of the impeller that makes liquid to be drawn into the pump. As the fluid moves outward due to centrifugal force, it gains velocity and is discharged from the pump outlet.

Centrifugal pump or multi-stage pump is used for its ability to handle high flow rates and is commonly employed in applications where a continuous and consistent flow of liquid is needed. Here are some common applications of centrifugal pumps:

Water supply: Centrifugal pumps are extensively used in municipal water supply systems to transport drinking water from treatment plants to distribution networks and to our homes.

Agriculture: Centrifugal pumps are used for irrigation purposes to distribute water to fields for crop cultivation.

Industrial processes: Many industries use centrifugal pumps to transfer and circulate various liquids, such as chemicals, solvents, and abrasive fluids, in processes like chemical manufacturing, pharmaceuticals, and food production.

Wastewater treatment: Centrifugal pumps are used to move sewage and wastewater through treatment plants.

Oil and gas industry: These types of pumps are utilised in the transfer of fluids with high viscosity demanding high flow rates, including crude oil and various other chemicals.

What are Reciprocating Pumps?

Reciprocating pumps functions by using a back-and-forth or reciprocating motion to transfer fluids. Unlike centrifugal pumps, which rely on rotation, reciprocating pumps utilise a piston, diaphragm or a plunger to displace the fluid in a controlled manner. This reciprocating action creates a pressure differential that draws in the fluid on one stroke and then pushes it out on the return stroke.

Reciprocating pumps are known for their ability to generate high pressures which is suitable where liquids need to be transported with significant force. These pumps come in various designs, including single-acting and double-acting, and can be powered by electric motors or internal combustion engines.

One of the key advantages of reciprocating pumps is their ability to maintain a constant flow rate and handle fluids with less viscosities, making them suitable for a wide range of industries. They are commonly used in applications where a consistent and controlled flow of liquid is critical, such as:

Hydraulic systems: Reciprocating pumps are essential in hydraulic systems, where they supply the high-pressure liquid needed to run machinery and heavy equipment, such as construction machinery and industrial presses.

Water blasting purposes: They are used in high-pressure cleaning equipment for tasks like industrial cleaning, paint removal, and surface preparation.

Water jet cutting: Reciprocating pumps are crucial components in water jet cutting machines, where they create a high-pressure water stream for precision cutting of materials like metals and stones.

Oil well drilling: In drilling operations, these pumps are used to inject drilling mud into wells to control pressure and remove cuttings.

Centrifugal Pumps Vs Reciprocating Pumps: Comparing Various Aspects

Let’s break down the differences between centrifugal pumps and reciprocating pumps in various aspects, so you can get a clear picture of what sets them apart.

Operating Principle

1. As mentioned above, centrifugal pumps work on the principle of centrifugal force. They use an impeller that rotates on high speed to create a flow of fluid. The fluid is drawn into the centre and expelled outward due to the spinning motion.
2. Reciprocating pumps uses back-and-forth motion of piston or diaphragm to displace the fluid. This reciprocating action creates pressure differentials that move the fluid.

Capacity and Head (Pressure):

1. Centrifugal Pump offers variable capacity by adjusting impeller size or rotational speed, resulting in increased head and flow rate. It is known for its high capacity-to-footprint ratio but not suitable for high-pressure requirements.
2. Reciprocating pump provides a fixed discharge volume per rotation, and capacity is increased by altering plunger or piston size or rotational speed. Reciprocating pumps are well-suited for high-pressure use but have a larger footprint compared to centrifugal pumps.

Effect of viscosity

1. Centrifugal pump shows a relatively constant flow rate over a wider range of pressure, with fluid viscosity having less effect on flow rate when pressure increases.
2. In reciprocating pump high viscosity fluids significantly affect performance which leads to reduced flow rate, and increased power requirements.

Performance

1. Performance of centrifugal pumps varies with different operating points that changes in flow output affecting pump head and increasing reduction discharge flow rate and vice versa.
2. Reciprocating pump maintains a constant flow rate, regardless of the system's resistance. The pump will operate at different pressure levels without changing flow rate when faced with variations in system resistance, safety factors, or safety margins.

Area required for installation

1. Centrifugal pumps typically require less floor space for installation. Their compact and simplified design makes them a space-efficient choice.
2. Reciprocating pumps need a larger floor area for installation. Their design includes components like crankshafts, pistons, and connecting rods, which occupy relatively more space.

Cost of installation and operation

1. The initial installation cost of centrifugal pumps is usually lower and operational costs are reasonable. This is because centrifugal pumps have a simpler design with fewer moving parts.
2. Reciprocating pumps require higher cost of installation due to their more complex design, involving components like pistons, connecting rods, and valves. Additionally, their installation can be more labour-intensive. Operation costs can be higher due to greater maintenance demands.

Here is a comparison of centrifugal pump and reciprocating pump in tabular form:

Centrifugal Pump Vs Reciprocating Pump: What Should You Choose?

Choosing between a centrifugal pump and a reciprocating pump depends on the specific needs of your application. Here are some essential factors to consider helping you make the right choice:

Define your application requirements: Understand the exact requirements of your application. Consider factors such as flow rate, pressure, and the nature of the fluid you need to move.

Flow rate and pressure needs: Decide whether your application requires a high flow rate, a high pressure, or a combination of both. Centrifugal pumps are better for high flow rates, while reciprocating pumps are suited for high-pressure applications.

Energy efficiency: Consider the energy efficiency of the pump. If energy efficiency is crucial for your operation, you'll want to choose a pump that matches your flow and pressure requirements while minimising energy consumption.

Maintenance requirements: Assess the maintenance costs associated with the pumps. Centrifugal pumps generally require less maintenance due to their simpler design, while reciprocating pumps may need relatively regular upkeep due to their moving parts.

Fluid compatibility: Assess the compatibility of the pump with the fluid you need to move. Some fluids may be corrosive, abrasive, or viscous, which can influence the choice of pump.

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FAQs on centrifugal pump vs reciprocating pump

What is a Centrifugal Pump?

A centrifugal pump is a type of pump that works by using fast-rotating impellers to add kinetic energy to a fluid. This kinetic energy is then converted into pressure head as the fluid exits the impeller. Centrifugal pumps are ideal for applications requiring high flow rates but are not well-suited for high-pressure scenarios.

What is Reciprocating Pump?

A reciprocating pump uses a crankshaft-connecting rod mechanism, similar to internal combustion engines, to create a reciprocating linear motion of plungers or pistons. This back-and-forth motion displaces the fluid and accurate pressure and flow control through check valves.

Is centrifugal pump heavier than reciprocating pump?

In terms of physical weight, reciprocating pump weighs more than the centrifugal pump due to their design, which involves a crankshaft-connecting rod mechanism and sturdy components for handling high-pressure use.

Where is the reciprocating pump used?

Reciprocating pumps are commonly used in applications that require high pressure, such as oilfields, industrial water blasting, and other scenarios where fluids need to be pumped at significantly elevated pressures. They are preferred for lower volume, high-pressure tasks.

Where is Centrifugal pump used?

Centrifugal pumps are utilised in various industries, including water treatment plants, irrigation systems, and cooling systems in automobiles. They are favoured for tasks that involve moving large volumes of fluid at lower pressures. Their efficiency in handling high flow rates makes them suitable for applications where pressure is not the primary concern.