A pump is a mechanical device used to transport liquids or gases from one location of lower pressure to another location of higher pressure. Energy is added to the entire system in order to overcome the difference in pressure. Mechanical forces are present in the functioning of pumps as the liquid or gas being transported is either lifted physically or moved through compression forces. Gas pumps most often use compression forces and are usually called compressors except in cases wherein fans or blowers are utilized.
There are many types of pumps and the very first pump dates back to the 7th century B.C. as described by Archimedes. This pump, the Archimedes screw, was utilized in the water systems of the Hanging Gardens of Babylon. Al-Jazari (1973) was one of the most popular people in the world of pumps as he illustrated and described many different types of pumps such as the reciprocating pump, the double-action pump with pipes for suctioning, the water pump, and the piston pump.
Today, pumps are usually categorized into two different divisions: positive displacement pumps and rotodynamic pumps. These categories are descriptive of how these pumps work. Positive displacement pumps trap the substance to be transporated in one location called the inlet pressur section and then force it to be displaced to the discharge pipe. Subcategories of positive displacement pumps include the rotary pumps, the metering pumps, and the reciprocating pumps.
Rotodynamic pumps, on the other hand, utilize bladed impellers whose rotation within the fluid creates a tangential acceleration of the fluid which in turn creates an energy increase that supports the transport of the substance. Rotodynamic pumps are subcategorized as kinetic pumps and centrifugal pumps. Other special types of pumps include jet pumps, viscous drag pumps, double volute pumps, chopper pumps, rotating casing pumps, recessed impeller pumps, self-priming pumps, slurry pumps, and sludge pumps. (Chaurette, 2004)
From left to right: double volute pump design, typical jet pump, venture action of a jet pump (Source: Chaurette, 2004)
In the processing industry, pumps have many different applications. The pumps in processing industries are used to transport the raw materials from one location to another. This may involve the transport of ink, pigment, and paint in chemical processing. In the sugar processing industry, pumps are utilized in material transfer from the raw juice, to the cush-cush, to the lime slurry aspects of processing and even more. Pumps are also used in livestock processing as evidenced by its use in feed distribution.
In agricultural processing, pumps are most often the key machines involved in the transport of water. This is very similar to the use of the first noted pump for the water systems of Babylon. These not only include distribution of water in the system but also the elimination of wastewater from the system. This links with another application of pumps, sewage management as seen in the pumps application for grit removal, waste-activated sludge removal and the like.
The ideal feature that pumps provide processing industries is the option of bulk transfer. This speeds up the processing time and allows for a more cost-efficient system. Over-all the simple physical mechanics of a pump have been utilized to create numerous types and designs that have been able to improve the operation of the processing industry. Pumps are now an essential part of processing. Soon, new innovations in pump design will surface as a result of the processing industries demand for higher efficiency.
Al-Jazari, I. (1973). The Book of Knowledge of Ingenious Mechanical Devices : Kitáb fí ma’rifat al-hiyal al-handasiyya, translated by P. Hill. New York, NY: Springer Publishing Company
Chaurette, J. (2004). Specialty Pumps. Fluide Design Inc. Retrieved 25 March 2008 from www.fluidedesign.com