The choice of a pump for any purpose requires the calculation of its performance. It is convenient when the water pressure in the faucet is regulated in such a way that at its highest value splashes do not scatter to the sides, and at the same time you do not have to wait long for a large container to be filled. We will talk about how to determine the performance of the pump later in the article.
Pump selection parameters
There are two ways to get the optimal pump head: artificial throttling or precise selection of device parameters. If you choose it according to the principle “the one that the neighbor has is better”, then there is a high probability of a weak jet pressure with the simultaneous inclusion of several flow points. Or you will have to restrain the flow of water by partially shutting off the tap, which reduces the efficiency of the device, and therefore increases the cost of funds during its operation.
Professional approach to the issue of water supply requires consideration of many points:
- pump power;
- feed pipe thickness;
- trunk length;
- numbers and shapes of fittings;
- number of taps.
Naturally, it is very difficult to foresee everything, therefore, with a complex systemplumbing communications for greater efficiency, several pumps are used. Each performs its own function: one fills the water intake tank from the well, the other provides water to the house, the third waters the garden.
Pump characteristics, pressure
Pumps have many features. In order for the consumer to decide what type of device he needs, there are several basic indicators:
- The volume of fluid supply, or pump performance. It shows how much water the unit can pump over a certain period of time. This means that the liquid flows directly at the outlet of the device. To determine the volume at the end of the line, you must subtract the pressure loss in the latter.
- The amount of pressure, or pressure. Shows how high the pump is capable of lifting water. This does not take into account the height from the device to the level of the water surface.
- Height to water intake, or backwater. The distance from the water surface to the outlet of the suction pipe is strictly defined - the excess leads to the appearance of cavitation in the working space of the unit. This can change important characteristics of the pump or simply prevent it from pumping water. The backwater can be increased by installing an auxiliary pump in front of the main pump, right at the suction point. Exactly the same effect will be obtained when creating artificial air pressure inside the tank with liquid.
- Power of energy consumed.
Pump overview
Pumps can be classified according to the principle of operation, design features and purpose. There are also submersible and surface units. All of them are designed to pump liquid, but most provide not only it, but also the rise of water from different depths:
- Pumps for wells. Basically they are submersible models. They are characterized by the fact that they can lift water from great depths (they have no restrictions), depending on the power of the power unit. Create a powerful pressure in the pipeline.
- Drainers. They have higher performance, but are not designed to create high pressure, they do not give high pressure. Convenient in that they can pump dirty water with small physical particles.
- Centrifugal. Universal pumps. They can be used both in wells and for pumping fluid from tanks. They do not descend into the water and have a limited distance from the surface of the water surface to the inlet of the suction pipe. The pressure of the pump depends on the number of impellers and the power of the engine, but still they cannot raise the water column higher than 120 meters.
- Vortex. They look like centrifugal ones, but the impeller is organized differently here. With less engine power, they provide high pressure and performance. They raise a column of water over 160 m. The disadvantage is the exactingness of its purity.
- Circulating. They do not lift water from the depths, but also create a certain pressure and work at elevated temperatures.
Pumps: supply,pressure
Maybe not everyone knows, but pumps work in tandem with atmospheric pressure. They simply create an area of discharge and injection. Therefore, no matter what efforts we make from above, using the most powerful units, it will not work to raise water from a great depth. As soon as the force of air pressure is balanced by the force of gravity, the water in the pipe will stop. To lift from the depths, powerful submersible devices are used that create pressure.
The main characteristics of the described units are the pump pressure, performance. They have a certain relationship with each other. So, pressure is understood as the ability to supply water to a certain height or move it in a horizontal direction to a given length. It is clear that the same pump will produce different pressures at a height of 20 and 120 m.
Head must be known when choosing the type of pump. Each model can create strong or weak pressure, which is due to the design of the working mechanism. When a fluid comes into contact with a wheel blade or a membrane or a piston, it receives a certain charge of kinetic energy, which lifts it up.
The most efficient centrifugal systems are those with multiple impellers in series. They are head boost pumps and have very high efficiency.
How to adjust the pressure
In any complex plumbing system, the pressure generated by the pump must be controlled. There are four ways to influence the pressure:
- Throttling. The essence of the method isthe fact that a special throttle is installed at the outlet of the device or on the suction pipe. An ordinary crane can act as its role. At the installation site, depending on the diameter of the orifice, part of the pressure is extinguished. With the position of the water flow limiter at the pump outlet, the efficiency of the device decreases, since when the pressure in the electricity system decreases, the pump consumes the same amount.
- Electrical speed control of the impeller. This is the most efficient method without loss of pump efficiency. The water supply is reduced with a proportional decrease in power consumption.
- Mechanical speed reduction. In this case, a reduction gear is used. The method is economically unprofitable - after all, the engine consumes the same power and an additional mechanism is needed - a gearbox.
- Bypassing. A jumper is placed between the outlet and the suction pipe of the pump. It turns out that part of the liquid simply circulates in a circle without doing useful work. As a result, the pressure in the pipes drops, and the efficiency decreases.
What will be the pressure of the pump pumping water from above
When the water intake tank is located above the place of installation of the pumping system, then practically no energy is spent on suction. Then, to calculate the pump head, use the following formula:
Htr=Ngeo + Nloss + Hsvob - Tank height.
Htr here is the required pressure value, due to the costs of the consumer.
Ngeo - the difference in levels between the pump installation platform and the highestwater consumption point.
Losses - loss of overcoming the friction force in the supply line, with the exception of the section of the vertical pipe from the supply tank to the pump.
Нsvob - pressure from consumption points when they are fully open.
Tank height - the value of the height between the tank and the pump.
Injection of water from depth
How to determine the pressure of the pump when pumping water from a well, water storage pit or well? The calculation formula becomes:
Ntr=Ngeo + Nloss + Nfree + Source level.
In it, all the terms are the same, except for the last one - Level of the source, - which is the difference between the suction point of the liquid and the pumping device.
What is a pumping station
The pumping station is a system of a pump and a hydraulic tank working in pairs. Plus, they come with a special pressure control relay. The hydraulic accumulator here serves as an element smoothing the pressure of the pump, preventing the frequent switching on of the electric motor and leveling possible water hammer in plumbing communications.
Stations can be based on any type of pump, using any battery capacity. The larger the hydraulic tank, the stronger the additional lift generated by it.
Conclusion
When the water pressure in the pump is insufficient, you can get out of the situation by installing two or more units in series. This scheme is often used for deep wells, where at the bottominstall a submersible unit that supplies water to the suction pipe of the centrifugal.
