Pump head is one of the most important parameters to know before purchasing a system. It is a highly technical specification, calculated in a complex way, but it indicates whether a certain pump is suitable for your needs. Otherwise, you may find yourself with a pump that fails to work in the required way, wasting time and money.
In recent years, technological innovation has led to significant improvements in pump performance. Today, these are much more reliable and versatile than in the past. CDR Pompe always strives for the highest quality and efficiency possible, and we can also assist you in selecting the best pump for your needs in the industrial, chemical and pharmaceutical sectors.
In this article we will tell you all about head, a type of parameter that you may not be familiar with. We’ll explain what it is, how it is calculated and why it is essential to understand it.
First let’s clarify what is meant by pump head
The head is a very important physical quantity that indicates the maximum height to which a pump can lift a fluid. In the most common measurements, it is expressed in meters. In essence, head refers to the pump’s ability to overcome the difference in height between the suction point (the area from which the liquid enters the pump) and the delivery point (the outlet area or flange where the fluid exits the volute), taking into account any pressure drops caused by friction and other particular resistances that the system may have.
We could also define the head of a pump using other terms, such as the energy per unit of mass provided by the pump to a fluid.
The head is calculated as the sum of the geodetic head and losses in pressure, and is essential to ensure that a pump is suitable for the specific needs of a system.
An insufficiently high head value can also cause malfunctions. As a result it is essential to know this value at the time of purchase. In summary, head is a key indicator of a pump’s operational efficiency in the transfer of fluids in various application contexts, both industrial and beyond.
How head is calculated
The formula to calculate the head is as follows: H= Hgeo + (Pa-Pe)/* g + (va2-Ve2)/2g + Hv. We will now explain the individual elements of the equation.
- H: is the head of a pump, which is expressed in metres;
- Hgeo: geodetic difference between the free surface of the tank and the pump’s suction point
- Pa: atmospheric pressure;
- Pe: tank pressure;
- p: density of the fluid;
- g: gravitational acceleration constant, 9.81 m/s2
- Va, Ve: speed of the liquid in suction and delivery;
- Hv: pressure losses in the circuit.
Mathematically, the head of a pump is inversely proportional to the flow rate of the pump itself. The flow rate is simply the amount of fluid (or volume) that passes through the pump per unit of time. Therefore, the greater the pump flow rate, the lower the head.
The head value can be obtained through calculations that are relatively simple. Fundamentally, what you need to know is simply the physical characteristics of the fluid and the pump. Alternatively, you can also refer to the data of the system, specifically regarding head losses, height differences or pressure differences.
The head is a crucial factor for purchasing a pump
Before purchasing a pump of any type, magnetic drive pumps and mechanical seal pumps, knowing the head value is absolutely crucial. Different models have different head values. Even seemingly identical models may have specifications that do not match those desired.
The head value can usually be found on the product’s datasheet. It is therefore not a hidden value, or to be calculated independently. It must be freely available to the customer at the time of purchase.
A key piece of advice is therefore to never buy a pump if the head value is unknown, or worse, if this value is deliberately concealed.
For over 70 years, CDR Pompe has been at the side of companies as leaders in fluid technology. With passion, experience and constant innovation, we aim to provide you with devices for handling corrosive liquids that operate with the utmost safety and reliability.
Our business activities are spread across more than 50 countries. Today, we are national and international leaders with a distribution and partner network that allows us to operate anywhere in full efficiency.