The Pressure Pump – Its Action and Some Common Uses

At first glance, the term pressure pump may strike many people as an example of the grammatical error known as tautology or unnecessary repetition. While some people believe the primary purpose of pumping a liquid or gas is to raise its pressure, this is not the case. In practice, many pumping devices are incapable of doing so. For example, the screw-like machine, attributed to the ancient Greek philosopher Archimedes, still used in some countries today, can do no more than generate a flow of water from a river to a higher position on the shore.

Except for purpose-built pressure pumps, the primary task of pumping equipment is to convey a liquid, gas or slurry from point A to point B. As long as it can expel its contents at the same rate they are drawn in; there will be no change in pressure. Only when impeding the discharge of its contents, will such changes occur. 

The simple act of compressing the tip of a garden hose illustrates this effect rather well. Before compression, water enters and exits at the same speed. Squeezing its end slows the flow, but the exit jet becomes stronger, mimicking the action of a pressure pump. In practice, pump designers achieve this effect in several ways, such as tapering the outlet port or incorporating an adjustable nozzle. The latter option can produce the exceptionally high-water pressures necessary for heavy-duty cleaning tasks. However, more commonly, the need is merely to boost the flow of liquid in a pipeline, and, therefore, such extremes are unnecessary.

In a horizontal pipeline, friction will tend to slow the flow of liquid over long distances. The most effective way to keep a pipeline’s contents moving is to install pressure pumps at appropriate intervals to provide the necessary boost. In practice, gradients pose more of a challenge for pipeline operators.

In most cases, a downward slope can be a benefit. The engineers of ancient Rome relied on this principle when planning their aqueducts. They used the high flow rate attained during a long downhill section to provide sufficient kinetic energy to overcome gravity and maintain the flow on later uphill sections. In a pipeline, such as that used by municipalities to distribute water to homes and businesses, modern engineers employ a pressure pump to achieve the same ends.

Other applications for booster devices include raising water from a well or borehole, conveying water to the rooftop storage tank of a sprinkler system and transferring harvested rainwater from the collection vessel, to name just a few.

For more information on pressure pumps, please feel free to contact us at Bestline Manufacturing.