Surface pumps are used in private water supply systems. They are used to lift water from a shallow depth - no more than 8 meters and to maintain constant water pressure in the water pipe. Systems of continuous water supply in cottages are performed with the use of surface pumps. Surface pumps are also used to irrigate the plantations.
Surface pump for
Wells The main difference between surface pumps and submersible pumps is that the pump itself is installed in any suitable place, and the suction hose or pipe is lowered to the water source. This is convenient for suburban areas without permanent residence, because of the small size and weight of the surface pump can be quickly installed and disconnected from the water pipe.
Types of surface pumps and their device
Surface pumps are of two types:
- Vortex;
- Centrifugal.
Vortex pumps are low price and compact, do not require much space for installation. They have a simple design: inside the housing there is an electric motor that transfers rotation to the shaft, which in turn rotates the wheel with the blades. At the entrance, a filter is installed that retains sand and other small particles. The pump transfers the energy of rotation of the liquid motor coming through the inlet branch pipe, and due to the compression of the water inside the pump, the pressure of the liquid at the outlet from it increases.
Vortex pumps and open-type pumps
The advantages of vortex pumps include their small size, the ability to install in a confined space, the ability to raise pressure to significant values compared to centrifugal pumps of the same power. Vortex pumps have the ability to self-suck, this eliminates the need to fill the supply pipe before starting work. Disadvantages - low efficiency, no more than 0.45, as well as the impossibility of pumping liquid with a large number of inclusions, which leads to rapid failure of internal wheels and blades. This feature does not allow the use of vortex pumps for lifting water from reservoirs and wells, especially with a sandy and silted bottom. Vortex pumps are used to increase the pressure in the water supply system and pumping water from the storage tanks.
Centrifugal pumps can be used at depths of up to 9 meters. According to its design, centrifugal surface pumps are generally similar to vortex pumps, the difference is that the fluid does not move due to the lifting of their blades, but due to centrifugal forces.
Scheme of the centrifugal pump
To increase the suction depth, centrifugal pumps use built-in or external ejectors. Their purpose is to pump air from the liquid supply system before switching on and during the operation of the centrifugal pump, as well as increasing the pressure. External ejectors are more efficient than built-in ones, they are installed immediately after the bottom valve at the source of water intake and increase the pressure in the system.
Sample of operation of external ejector
Advantages of centrifugal pumps - small size and weight, the ability to work with the presence of air bubbles in the system. This feature is used to provide private water supply and water intake from shallow wells and wells. Centrifugal pumps have a higher price than vortex pumps, and more stages.
Application and use of
As already mentioned, surface pumps are widely used in private water supply systems. This type of pump is not designed for pumping other liquids and corrosive media. The suction hose must be equipped with a strainer and a check valve.
Surface pumps application
The location of the pump must be selected based on operating conditions, taking into account that the longer the supply network, the lower the efficiency of the pump. At installation it is necessary to adhere to recommendations of the passport on the pump concerning depth. When calculating, it should be borne in mind that every four meters of horizontally laid pipes correspond to a meter of depth.
If the pump is to be used in the cold season, the supply and discharge systems, as well as the pump itself, must be insulated. The optimum solution widely used in water supply systems is the installation of a pump in the caisson - a recess with a lid for maintenance. The pipes are laid in the ground, at a depth of at least 1.5 m.
Selection of the
pump The selection of the surface pump must be approached from the point of view of the requirements for the pressure of the water. So, to ensure the needs of the suburban area, enough productivity of 1 cubic meter per hour. And for the needs of household water supply for a family of 3 people need a pump with the ability to pump 3 cubic meters per hour.
Also necessary to take into account the features of the housing. Pumps in plastic design significantly less weigh than similar models in steel or cast-iron housing. But they are less durable, so the choice of pump should be made taking into account the location of its installation and the maximum temperature of pumped water.
For continuous water supply, it is also possible to supply the system with a storage tank, and to install a pressure switch in the system, shutting off the pump when the water supply stops.
It will also be useful for you to read what pump to choose for the borehole, how to choose a faecal pump and how to choose a pump for the well.
