Volumetric pumps are devices used to transfer liquids from one point to another, exploiting the principle of moving a defined volume of fluid for each operating cycle. Generally, pumps have the ability to transfer a fluid from low pressure areas to high pressure areas, from lower places to higher ones, and from nearby places to more distant ones.
Whatever the type of pump, therefore, it is always about moving fluids from point A to point B. Unlike dynamic pumps (such as centrifugal pumps), which increase the pressure of the fluid through acceleration and its subsequent deceleration, volumetric pumps transfer the fluid by using the change in volume within a pumping chamber.
This type of pump is useful in many industrial applications due to its ability to ensure a constant and controlled flow of liquids. The main sectors of use include the chemical and pharmaceutical industries, the automotive industry, the oil and fuel sector, and water and industrial fluid treatment.
We at CDR Pompe would like to tell you about these pumps, their characteristics and their advantages in chemical, agricultural and other areas.
Volumetric vs dynamic pumps: what’s the difference?
Dynamic pumps and volumetric pumps are the two main types of pumps used for transferring fluids. They differ in operating principle and applications.
Dynamic pumps operate through the kinetic energy supplied to the fluid, which is then converted into pressure. This type of pump is ideal when you need to move large quantities of fluid with moderate pressure variations. Volumetric pumps, on the other hand, act by moving a fixed amount of fluid for each working cycle (for example, each turn of a piston or each movement of a membrane). These pumps are ideal for applications that require high pressures and constant flows. In addition to the ability to keep the fluid volume constant, dynamic pumps work regardless of pressure. This is very useful when you have to ensure a constant amount of fluid even if the flow resistance changes.
Neither pump is better than the other. Which one you choose depends exclusively on the type of application required.
How a volumetric pump works
The operation of volumetric pumps is based on a suction and discharge cycle. During suction, the fluid enters the chamber through an opening, while during the discharge phase, the chamber reduces in volume, pushing the fluid towards the outlet. Each operating cycle corresponds to a complete rotation of the pump shaft (360°), and the volume pumped is constant and independent of the fluid pressure.
Volumetric pumps are often used to handle viscous, corrosive or solids-containing fluids. This makes it an excellent and reliable solution for many applications, including the food and beverage industry.
Just like CDR’s magnetic drive pumps, there are also different types of volumetric pumps. Rotary volumetric pumps and reciprocating volumetric pumps are both designed to move a precise volume of fluid continuously. They differ in their operating principle and mechanical configuration.
Rotary and alternative volumetric pumps
Rotary volumetric pump
Both pumps, therefore, perform the same function but in a different way. Rotary volumetric pumps exploit the rotary movement of an element (for example gears, screws or blades) to trap the fluid and transfer it from one area to another. During the movement, the liquid is constantly pushed through the pump. The flow rate delivered is independent of the head and is instead directly proportional to the rotation speed.
Within rotary pumps, there are some differences in operation:
- Gear pumps: they take advantage of the action of two gears that move the fluid by rotating in opposite directions.
- Lobe pumps: in this pump, two rotating lobes lead to the formation of ejection and suction chambers for the fluid.
- Screw pumps (or double screw pumps): the action of rotating screws is used to move fluid continuously.
reciprocating volumetric pump
Reciprocating pumps operate through the rectilinear movement of a component (such as a piston or diaphragm) that changes the volume of the cavity in which the fluid is trapped. This alternating (or oscillating) movement allows a fixed amount of fluid to be moved with each cycle. This category of pumps is ideal for handling fluid in a constant and controlled manner. Depending on the type of element that generates the movement, these pumps are also divided into subcategories:
- Piston pumps: they use a piston that moves inside a cylinder, which compresses and moves the fluid. These pumps are very useful for very high pressures and relatively low flow rates.
- Membrane (or diaphragm) pumps: They use a flexible membrane that moves alternately to displace the fluid. This type of pump is often used in applications that require separation between the pumped fluid and the mechanical drive, such as in the food and chemical sectors.
Advantages and disadvantages of using a volumetric pump
Volumetric pumps offer numerous advantages, making them ideal for applications where a constant and precise flow is essential. First of all, they guarantee accurate flow regulation, regardless of pressure variations, allowing precise control of the volume of fluid transported.
In addition, they are particularly suitable for viscous fluids, since their operating principle does not depend on the speed of the fluid. These pumps also offer high operating efficiency, especially in low and medium flow applications. Another strength is their ability to generate high pressures, which makes them indispensable in sectors where high pressure values are required.
Their principle of operation also makes them very resistant to wear. This translates into lower maintenance costs and longer service life, resulting in considerable economic savings. Finally, they also have the ability to treat very sensitive fluids, which could be affected by more aggressive and direct pumping actions.
The disadvantages: Energy efficiency and mechanical complexity
Although there are many real advantages offered by volumetric pumps, we must also mention some drawbacks in their use and maintenance. First, their underlying mechanical complexity makes them more difficult to maintain than
centrifugal pumps, especially when using mechanisms such as pistons or gears.
Secondly, they can sometimes be less efficient than other types of pumps, especially when it comes to high speeds or large volumes.
Here at CDR Pompe, we continue in 2025 to work with passion, in order to offer you the best possible solutions for handling industrial, chemical and pharmaceutical fluids. Our ability to respond effectively to customer requests and our extensive range of pumps have allowed us to become leaders in the process pump sector. Visit our website or contact us directly. Together, we can find the best solution for your business.
