In layman’s terms, gear pumps are a type of positive displacement pump that are used to transfer liquid from one place to another. With the help of rotating cogs inside the pump housing, the mechanical pumping action creates a smooth and steady fixed-volume flow, making them a popular choice for all sorts of applications. One commonly asked question though is whether or not gear pumps can be used for water. To get to the bottom of that question, lets first take a look at how gear pumps actually work.
How Do Gear Pumps Work?
As the cogs inside of the gear pump turn, their action allows the pump to transfer the liquids. A seal is created by the rotating element, which causes suction to occur at the pump’s inlet. As liquid is then drawn into the pump, it is carried by the cavities of the rotating gears and transported over to the discharge outlet.
There are two different types of gear pumps: external gear pumps and internal gear pumps. The gears inside external gear pumps are both identical and sat opposite from one another so they can interlock in the middle. In most cases only one of the gears is actually driven by a motor, allowing it to drive the second idler gear itself.
As the gears turn away from the pump’s inlet an opening is created, allowing the liquid to fill the void. The gear teeth then trap it here as the gear continues to turn around the casing, moving it towards the discharge area. As the gear teeth interlock on this side of the pump, the available space for the liquid is reduced and the pressure forces it out the other end.
Internal gear pumps operate on a similar principle, only the gears are different sizes and one is inside the other. This allows water to be brought in between the two and pushed out of the voids at the outlet in much the same way as it turns inside the casing.
What Are Gear Pumps Used For?
External gear pumps are typically used when high pressure is necessary. This could be with chemicals, alcohols, fuel oils, solvents, or hydraulic applications. Internal gear pumps on the other hand are used for high viscosity liquids, like fuel oils, polymers, resins, food products, or inks and paints.
While internal gear pumps wouldn’t be so suited to low viscosity liquids like water, external gear pumps are commonly used for the task. In many cases water needs to be pumped at high pressures, making it the perfect application for an external gear pump.
For more information on gear pump uses and the best type of pump for your application, speak with our expert team today.
