How to define the displacement of a gear pump?
In the field of hydraulics, many layers of information and realities coexist and define each other. A gear pump itself is dependent on its environment and interacts with the rest. But for the whole system to work, everything must be in its place and well oiled. So how do you know that a gear pump's displacement is well defined and corresponds to its intended use
Before we look at the displacement of these pumps, let's start by describing them. What is a gear pump? A gear pump is, for starters, a pump that uses the combined profile of two gears to initiate liquid displacement in a motor. These pumps are exclusively coupled to hydraulic motors and can only be used in hydraulics. They are therefore, logically, hydraulic pumps. Two types of pumps can be distinguished, the pumps that we will call simple, or internal. A simple pump uses a rotor and a pinion, both of which are driven to create a space to suck in the liquid product and inject it into our system.
The pumped product then moves on either side of this rotor/pinion couple, until it exits the valves that depend on it to operate. Internal pumps are used in automotive and industrial applications. They use a positive displacement principle. The pump is equipped with a card in which there is a double gear. This double gear combines an externally geared rotor and an internally geared pinion, as well as a crescent for the discharge of the liquid. As in the simple model, the interaction of the two parts creates a suction effect, the purpose of which is to inject the displaced liquid into the crescent. Both pumps have their own advantages, interests and fields of application.
Nevertheless, what unites them is the simplicity of their mechanics and the fact that their structure is compact, simple and therefore durable. Moreover, these qualities make them very energy efficient and therefore very attractive for many professional applications in the industrial, technical or automotive field.
Now that we have clarified our subject a little, let's turn to what we are dealing with today, namely the displacement of these pumps. What are they and how can we define them
The displacement of gear pumps
The use of these pumps makes it possible to estimate rather easily the pressure limits they will have to undergo in their use. Their nature and their constitution make them useful only in certain contexts and the pressures often remain confined below certain extreme values.
As a result, their maximum pressure often remains below 200 bar, which has an impact on the displacement they will need to operate. Common displacements for these pumps range from 0.25 cm3 to 250 cm3 for the most powerful.
These displacement volumes imply maximum operating pressures of 125 to 250 bar (for the higher ranges).
As we have seen, the displacement is determined according to the use of the pump, which in turn has an impact on the bars that the pump will have to withstand in terms of maximum operating pressure.
It is therefore necessary to know the maximum pressure that the pump will have to withstand in order to calibrate its displacement accordingly.
We have seen here how to estimate and recognize the displacement of a hydraulic gear pump. See you soon for new articles