Gear Pumps Benefits

What are Gear Pumps and What are Their Benefits?

There are many reasons why it may be necessary to transfer a liquid between two points, and there are probably almost as many ways to achieve this. However, a pump is almost always the most efficient and widely used of the available options. These devices can take many forms and employ different operating mechanisms that, in turn, determine their suitability for a given task and their respective benefits and drawbacks. Even individual types will often have one or more variants. For example, there are two main types of gear pumps – internal and external. While the two only differ in the arrangement of their gears, that difference has a marked influence on their performance.


External Gear Pumps

Gear Pumps

Each type operates on the same principle by trapping fluid between the teeth of rotating gearwheels. In the external variety, the teeth of two equal-sized wheels mesh to trap and propel the liquid. Generally, one of the wheels is mounted on a driveshaft and powered by an electric motor or internal combustion engine, causing the second gearwheel to rotate in the opposite direction. However, in some models, both wheels are motorised. In both internal and external gear pumps, a liquid is drawn into the open gaps between the teeth from the suction side. As the wheels rotate, those gaps start to close. The trapped fluid can only move forward and will be drawn between the two wheels and the closely-fitting outer housing, forcing it to exit from the discharge side.

Some external models are less suitable for handling thin fluids because of the fine clearance between the gearwheels and the casing. Some employ helical or herringbone gears, but most use spur gears as these are easier to manufacture, making the spur gear pumps the cheapest of the three options.

Nevertheless, their design makes them a viable choice for applications requiring high pressures and handling viscous fluids, such as lubricating and fuel oils. Also, models containing spur-type gearwheels tend to cope better with thin liquids like alcohol and other organic solvents than either the helical or herringbone variants. Other advantages include high-speed and relatively silent operation, easy maintenance, and reliability. Furthermore, the external types are less expensive than internal models, but unfortunately, they also have one significant disadvantage. External gear pumps are unsuitable for use with liquids containing entrained solids.


Internal Gear Pumps

While both rely on the action of gearwheels to move a liquid, the internal type has a radically different design. In this case, the two interlocking wheels are not located side by side, and they are also of unequal size. Instead, a smaller driving wheel with outward-facing teeth is positioned eccentrically inside a second and larger idler wheel with inward-facing teeth. As the inner wheel rotates, the outer one interlocks and moves in the same direction. Among the main benefits of these internal gear pumps are that they only have two moving components and require a single seal to prevent leakage around the driveshaft.

Their non-pulsing action ensures a constant fluid regardless of the pressure conditions. Also, these devices are bi-rotational. That means the user can employ the same device, whether filling or emptying a container. Because they are particularly well-suited for handling high-viscosity liquids, these units are favoured for numerous applications in many industries. For example, while used to transfer paints, pigments and inks, polymers and resins, these powerful internal gear pumps can also handle bitumen, tar and asphalt with equal efficiency.

However, some of the most surprising uses for this type of device one might encounter are found in the processed food industry. Their exceptional ability to handle highly viscous fluids in other sectors also makes them the perfect choice for transferring products like peanut butter, corn syrup, chocolate, vegetable fats and cacao butter. Another advantage of their even and continuous fluid delivery is that, when made from a suitably corrosion-resistant material like stainless steel, internal gear pumps can also be used to transport acids. On the downside, these units are a little more expensive than the external models and work best at medium pressures.


A Leading Manufacturer and Supplier of Gear Pumps

While choosing the best model for any given task can be challenging, it is essential to make the correct selection to ensure optimum performance and safety. If in doubt, it’s always advisable to seek some expert help. Prochem Chemical Pump Manufacturers is an industry leader and uniquely positioned to supply professional advice and world-class products when you’re shopping for gear pumps contact us today.

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