Hydraulic pumps are devices whose task is to move water from one point to another, whether on the same plane or at different heights.
Hydraulic pumps are devices able to move fluids by means of the energy produced by a motor in a closed circuit. The energy produced makes it possible to move water from one point to another.
Their origin dates back as far as the third century B.C.: it was Archimedes Pythagoric who designed the first pump in history. Over the centuries, the technological process has produced constant improvements for these devices, adapting them more and more to human needs. In this sense, first the combustion engine, and then the electric motor, marked a turning point in the design of hydraulic pumps.
In this post we will look at the different types, how hydraulic pumps work, and how to choose the one best suited to your needs.
Index:
- How the hydraulic pump works
- Centrifugal pumps: how they work
- Submerged pumps: ideal for wells and tanks
- Submersible pumps: water drainage
- Electronic circulators: what they are and their purpose
- Collection and lifting units
- How to choose the right hydraulic pump
How the hydraulic pump works
Flow rate, head and motor power. In order to understand how a hydraulic pump works and when you want to buy one, you have to consider above all these three aspects, which we will now analyse individually.
Let us start with the flow rate. This is the quantity of water (which can be expressed in litres or cubic metres) that a pump can move in a given time. The relationship is therefore between the quantity of water and time: X litres per second (l/s), X litres per minute (l/m), X cubic metres per hour (mc/h).
We wrote earlier that the task of the pump is to move water from one point to another, even on different levels. The head indicates precisely the difference in level that the pump, due to the pressure exerted, can move the water over. In this case, the metre is adopted as the unit of measurement. If a pump has a head of 10 metres, above this limit it will no longer be able to fulfil its task (e.g. bringing water from a container to the outside: if the container is higher than 10 metres, the pump will be less efficient).
Finally, we must take into account the power of the pump’s electric motor, which is expressed in kilowatts (kW). This measure is used to define the consumption of the electric pump and consequently the power it can exert in performing its work.
Three other aspects must also be taken into account when purchasing a pump:
– Dimensions of pipe connections
– Diameter of the axlebase
– Working pressure
This introduction was necessary in order to fully understand the characteristics of hydraulic pumps. Let us now take a look at what models are on the market and for what uses they are designed.
Centrifugal pumps: how they work
Centrifugal pumps, As the name suggests, they use the centrifugal effect of the impeller, a rotating organ placed inside, to do their work. The impeller is driven by the electric motor, and converts energy into pressure to move water.
In multistage centrifugal pumps, there are more than one impeller, and they act sequentially while working. This results in a progressive increase in the volume of water being pumped, and in the speed at which the pumping process is carried out.
But what are the advantages of multistage centrifugal pumps?
- Performance: Increased water pressure resulting in increased pumping speed and volume
- Models: Can be vertical and horizontal
- Durability: due to their higher efficiency they are more resistant to use than single-stage units
- Costs: the investment in multistage pumps is largely offset by lower operating costs
The centrifugal pump is used to draw water from a tank, to fill swimming pools, for irrigation in agriculture.
In order to choose the right size of a centrifugal pump, one must consider what water supply the pump needs to reach. Consequently, the head and flow rate must be taken into account, as well as the electrical power of the pump.
Submerged pumps: ideal for wells and tanks
Submerged pumps perform a specific job. They take water from a container (e.g. a well or a tank) and push it to the point where that water is to be used.
It is essential that the entire pump is covered by water, ‘submerged’, as its name indicates (see the example in the picture). Only in this way will the device function correctly.
Submerged pumps are generally in operation for very long periods of time. The water, covering them completely, has the function of cooling the motor without the danger of overheating.
They are therefore designed for long-lasting performance in relation to a low level of maintenance.
Being powered by electricity means that the length of the electric cable must be carefully measured, and it must also be sheathed and designed precisely for this function.
Submerged pumps should not be confused with submersible pumps, which we will analyse in the next section.
Submersible pumps: water drainage
Submersible pumps are used for water drainage.
This type of pump is suitable for domestic applications of stationary applications with automatic operation, for draining basements and garages subject to flooding.
The pump is placed below the water level but, unlike a submerged pump, once it has finished pumping water it has finished its task and is switched off.
Thanks to its compact and handy design, and the integrated float switch, it is particularly suitable for smaller sumps. It can be used as a portable pump for emergency cases such as: drawing water from tanks or rivers, emptying swimming pools and fountains or excavations and subways. Also suitable for gardening and hobbies in general. The integrated float level switch allows a fixed installation guaranteeing automatic operation.
Again, to optimise your purchase, you need to calculate the flow rate and head you need.
Electronic circulators: what they are and their purpose
Electronic circulators are a very important tool in heating systems. Their job is to bring water into the radiator and, in some types of system, also to the taps.
Today’s circulators are equipped with inverter motors.
They are able, thanks to this feature, to modulate the amount of energy in relation to the different demands of the user.
This pump puts water into circulation, starting from the device that produces the heat (i.e. the boiler) and arriving at the heat emitting systems in the room where they are located, i.e. the radiators.
Circulators make the most of the mechanical energy provided by the electric motor. This movement lifts the water and makes it flow within the circuit.
Collection and lifting units
Water collection and lifting units are other water handling mechanisms. They are intended for use in plumbing and heating systems.
These units act as a real pump when water from toilets, washbasins, showers or bidets cannot be expelled normally due to gravity problems.
It can happen, in fact, that there is a lack of pipe slope, or the existence of a toilet below the sewer level (e.g. in a basement).
These devices collect the water and pump it to the nearest gravity drain, through a small pipe that acts as a connection from the collection point to the discharge point.
How to choose the right hydraulic pump
Hydraulic pumps are devices used in many areas of daily life, in connection with moving small and large masses of water. The different types of pumps, analysed in this article, find their application in as many fields: from agricultural to sanitary.
Thechoice of the most suitable device for one’s needs depends, therefore, on its intended use. Based on this, you will then need to calculate flow rate and head in order to purchase the pump capable of doing the job you need.
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