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Pumps are mechanical devices designed to move liquids or increase their pressure. They convert the mechanical energy from a prime mover or external power source into fluid energy, enhancing the fluid’s pressure and flow. Pumps are widely used for transporting various types of liquids, including water, oils, acids, bases, emulsions, suspensions, liquid metals, gas-liquid mixtures, and fluids containing solid particles. Water lifting has always been crucial for human life and industry. In ancient times, many early water-lifting devices were developed, such as the chain pump in Egypt (17th century BC), the Chinese tangerine pump (17th century BC), the bucket and lantern system (11th century BC), and the water tanker (1st century AD). One of the most famous early inventions was the Archimedean screw, created around 3rd century BC, which allowed water to be lifted continuously to a few meters high—its principle is still used in modern screw pumps. Around 200 BC, the Greek inventor Ctesibius developed one of the earliest piston pumps, featuring components similar to those found in today's designs. However, it wasn't until the invention of the steam engine that piston pumps saw significant development. In the 1840s–1850s, the United States introduced the Worthington pump and the direct-acting steam piston pump, marking the formation of the modern piston pump. The 19th century was a golden age for piston pump innovation, with widespread use in hydraulic presses and other machinery. But as water demand grew, low-speed piston pumps were gradually replaced by faster centrifugal and rotary pumps starting in the 1920s. Despite this, reciprocating pumps remain essential in high-pressure, low-flow applications, especially diaphragm and plunger pumps, which offer unique advantages and are increasingly used.
Rotary pumps emerged alongside the growing need for diverse liquid transport solutions. The first recorded example was the four-blade vane pump in 1588, followed by various other rotary designs. However, these early models suffered from leakage, wear, and inefficiency. It wasn’t until the early 20th century, when rotor lubrication and sealing were improved, that rotary pumps became more practical, especially with the rise of high-speed motors. These pumps became ideal for higher-pressure, medium-to-low flow applications and for handling viscous liquids. Their versatility makes them suitable for a wide range of fluids.
The concept of using centrifugal force to pump water dates back to Leonardo da Vinci’s sketches. In 1689, French physicist Denis Papin invented a four-blade impeller centrifugal pump. Later, in 1818, the "Massachusetts pump" with radial blades and a volute appeared in the U.S., resembling modern centrifugal pumps. Between 1851 and 1875, multistage centrifugal pumps were developed, enabling high-head pumping. Theoretical foundations for impeller design were laid, and by the late 19th century, the advent of high-speed motors allowed centrifugal pumps to reach their full potential. With contributions from researchers like Reynolds and Pfrederick, pump efficiency improved significantly, expanding their application across industries. Today, centrifugal pumps are the most widely used type, with the highest output volume.
Pumps can be classified based on their operating principles, such as positive displacement pumps, power pumps, and others like jet pumps, water hammer pumps, electromagnetic pumps, and gas lift pumps. They can also be categorized by driving method (electric, water-driven), structure (single-stage, multi-stage), usage (boiler feed, metering), or the type of liquid they handle (clean, slurry, etc.). Positive displacement pumps operate by changing the volume within the pump chamber through reciprocating or rotating motion, allowing for precise flow control. Reciprocating pumps, such as piston pumps, have pulsating flow and require measures to reduce fluctuations. Rotary pumps, on the other hand, provide smoother operation and are suitable for small to medium flows under higher pressure.
Power pumps, such as centrifugal and axial flow pumps, rely on impellers to transfer kinetic energy to the fluid, converting it into pressure energy. They are known for stable performance and continuous flow but generally lack self-priming ability. Centrifugal pumps are the most common type of power pump, used in water supply, drainage, irrigation, and industrial processes. Other pump types, like jet pumps and gas lift pumps, utilize different mechanisms to move fluids, often in specialized applications.
Pump performance is measured by parameters such as flow rate, head, power, speed, and net positive suction head (NPSH). Flow refers to the volume of liquid pumped per unit time, while head represents the energy added to the fluid. Efficiency is calculated from these parameters and plays a key role in determining the pump’s performance. Pump characteristic curves, provided by manufacturers, show how performance varies with flow and head, helping users select the right pump for their application. Proper operation requires the pump to work within its recommended range to ensure efficiency and safety. Additionally, the viscosity of the fluid affects pump performance, and heating may be necessary to reduce viscosity and improve efficiency.