Difference between a gear pump and a piston pump

Difference between a gear pump and a piston pump

In recent days, pumps have become extremely widespread in various sectors. They do the same function as a heart does by taking in and pumping out fluids (or gasses) from one place to another. As opposed to merely moving up or down for fluid motion, a gear pump is similar to piston pump which both pumps and pushes against an object. The article will discuss differences between piston and gear pumps without necessarily going into much technical jargon.

Difference between a gear pump and a piston pump
Difference between a gear pump and a piston pump

Gear pumps have a fixed displacement, whereas piston pumps have variable displacement

A shaft, as it passes through a series of gears, drives a gear pump. These gears are arranged in such a way that they mesh with each other as well as with the shaft driving them. The rotation of the shaft moves each gear step by step through its entire range of motion, which includes forward and reverse movement, or any intermediate positions between them. It follows therefore that whenever one gear completes its revolution beyond the position of contact with another gear (i.e., when it goes through all of its motions), the process is completed.

The rate at which gears move in terms of number of revolutions per minute (RPM) is referred to as “speed”. Take for instance a diagram showing numbers marked on each individual gear in a gearbox indicating their speeds – for example if there were six gears in your box and each had an indicated RPM value of 1000 then your box would be capable of moving 6000 RPMs per minute (6000/1000=6000).

Gear pumps are typically smaller for a given flow rate compared to piston pumps

This happens because internal gears of gear pump are not as large as piston pump’s ones. Be that as it may, there are also some demerits. In the first place, gear pumps have higher pressure drop compared to piston pumps because of friction in the gears and seals. Furthermore, within high-flow applications where a slight volume reduction is acceptable like wastewater treatment, gear pumps take precedence over piston pumps.

Gear pumps are usually smaller for a given flow rate than piston pumps. Why is this so? This is because pistons move at slower speeds than gears do in electric motors and thus must have more space between them; some other parts such as bearings or seals can fill this space. More so, due to their size, piston pumps have higher pressure drops than gear pumps with each unit of volume pumped requiring more power to be moved by it per unit volume of fluid.

Gear pumps tend to be quieter than piston pumps

Such is the case because gear pumps are usually smaller than piston pumps and have fewer moving parts.

Piston pumps can be noisy too. They usually have a noise level of about 75 dBA (decibels) which is roughly equivalent to that of a lawnmower or a vacuum cleaner.

Gear pumps are likely to be more silent, however, this difference has not been as much marked as before. In recent years it has become common for gear pumps to have noise ratings of 40 dBA and even lower than that.

Gear pumps tend to have fewer moving parts than piston pumps

This therefore makes them more dependable and easier to service. If we are talking about dependability, gear pumps are the best option for long-lasting high durability applications.

Conversely, gear pumps are more capable in environments of extremities such as temperature or humidity. In such harsh situations, piston pumps have to be more intricate and get a lot of damages.

A piston pump cannot work well under all conditions; on the other hand, a gear pump cannot withstand some extremely severe conditions like extreme temperatures and high humidity.

Gear pumps can handle fluids with higher viscosity, but piston pumps can handle a lot more pressure than gear pumps

Low viscosity or low viscous fluids are the ones in which gear pumps are employed. While the fluid flows through it, a built-in gear within the pump rotates at high speed. The gear is connected to another one on a shaft that meshes with an external gear. As a result, this allows for more effective transmission of power from the pump to its load translating into increased efficiency and lower costs for the pump manufacturers. Gear pumps often come in handy when you want to transport fluids under extremely high pressure levels; for instance, while you would need to empty your hot water tank into your kitchen sink.

On the other hand, piston pumps do not have gears but instead they use pistons that move fluid inside tubes or pipes at high pressures by pushing against each other. In comparison to gear pumps, piston pumps have numerous advantages such as being cheap; requiring minimal maintenance; having lesser power requirements and also having higher temperature handling capabilities.

Gear pumps are usually smaller than piston pumps

This happens because a gear pump does not require the same amount of energy as a piston pump for water to be moved; hence, it can be smaller and cheaper. Conversely, a gear pump has less moving parts than in case of a piston pump which makes it work more efficiently and outlive the need for repairs.

Piston pumps are common in larger installations where they have to move significant volumes of water or provide high flow rates. They are also seen more often in home settings as used with lawn sprinklers or irrigation systems. On the other hand, gear pumps generally have increased pressure ratings as well as better flow capacities relative to those offered by piston pumps but still costing higher due to their smaller size and lighter weight.

There are instances when there is inadequate space available for a bigger pipe diameter system; thus, gear pumps become useful because they reach much higher pressures using smaller diameters than many other types of pumps would allow.

Gear pumps can handle more heat than piston pumps

Being more efficient than piston pumps is because gear pumps don’t depend on energy for the rotation of their shaft. The efficiency of a pump in terms of work done depends on how much pressure it pushes and thus can be very efficient over a wider range of pressures.

Piston pumps, unlike gear pumps, require lots of energy to rotate their shaft hence they can only operate under high pressure in a small flow rate range. They are however less efficient at lower flow rates compared to gear pumps which can still be very efficient at high pressures and flow rates.

Piston pumps are usually more expensive

These types of pumps are usually more expensive than piston pumps. That is because they are made in such a way that they will last for long and be powerful at the same time; thus, being able to move high volumes of water.

There is no need for electricity with piston pumps. As matter of fact, there are several battery-operated piston pumps. This means that it can be used in remote locations where there is no electricity or where the power supply needs to be monitored.

They are therefore ideal for irrigation systems particularly in rural farming areas. Besides, they come in handy when industrial applications like factories and warehouses need to pump fluids.

That’s all folks – gear pump vs piston pump. In addition, this comparison would help you determine what kind of a pump you should go for.

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