Max. performance
The maximum amount of water that the pump can deliver from the well per unit of time. The choice for this parameter depends on two main points: the maximum total consumption and productivity of the well.
The maximum total consumption is the amount of water that is necessary for the simultaneous normal operation of all points of water intake in the system. Different types of consumers (washbasins, showers, washing machines, etc.) require different amounts of water; exact values can be found in special tables or instructions for specific models of household appliances. And the total consumption can be calculated by adding the indicators of all points of water intake. As for the productivity of the well, this is the maximum amount of water that the well can produce in a certain time without draining it. This indicator is usually indicated in the documents for the well; if it is unknown, before buying a permanent pump, it is imperative to determine the productivity — for example, by trial pumping with an inexpensive unit.
Accordingly, the performance of the pump should not exceed the productivity of the well, and it should be at least 50% of the maximum total consumption of the connected water supply system. The first rule allows you to avoid draining the pump and the troubles associated with it, and compliance with the second guarantees a normal amount of water even with a rather intensive water intake. And, of course, do not forget that
high performance requires high power and affects the cost of the device.
Max. working pressure
The highest pressure that can occur in the line when the pump is running. Note that usually we are not talking about normal working pressure (it is described by max. head, see above), but about short-term jumps that can significantly exceed standard values. The water supply system to which the pump is connected must normally tolerate not only standard values but also the mentioned jumps — otherwise, an accident may occur. Accordingly, the maximum working pressure is useful for assessing how the safety factor of pipes, fittings and other elements of the system corresponds to the characteristics of the pump.
Operating principle
The basic principle or principles by which the suction action of the pump is carried out.
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Centrifugal. As the name suggests, this type of pump uses centrifugal force. Their main element is the impeller installed in a round casing; the inlet is located on the axis of rotation of this wheel. During operation, due to the centrifugal force that occurs during the rotation of the wheel, the liquid is thrown from the centre to its edges and then enters the outlet pipe directed tangentially to the circle of rotation of the wheel. Centrifugal pumps are quite simple in design and inexpensive, while they are reliable and economical (due to high efficiency), and the fluid flow is continuous. At the same time, the performance of such units can drop significantly with high resistance in the water supply system, and the resistance to pollution, although higher than that of vortex units, is still noticeably inferior to
auger ones(see below).
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Vortex. Vortex pumps are somewhat similar to centrifugal pumps: they also have a round casing and an impeller with blades. However, in such units, both the inlet and outlet pipes are directed tangentially to the impeller, and the blades differ in design. The method of operation is also fundamentally different — by the name, of it uses the vortices formed on the wheel blades. Vortex units are significantly superior to centrifug
...al units in terms of pressure but they are more sensitive to contamination — even small particles entering the impeller can cause damage, significantly reducing efficiency. In addition, the efficiency of such pumps is low — 2-3 times lower than that of centrifugal ones.
— Auger. The main part of such pumps is a rotor in the form of an auger (or several such rotors). The main advantage of pumps of this type is high reliability — they can easily cope even with very sandy water; in addition, the level of noise and vibration during operation is minimal. On the other hand, auger pumps are inferior to the options described above in terms of performance, and their cost is quite high due to the requirements for production quality.Max. immersion depth
The greatest depth under water at which the pump is capable of operating normally.
The optimal location for the deep well pump is as close to the bottom as possible (no closer than 1 m, but this margin can be ignored in this case). It is worth choosing according to the maximum depth, taking into account the depth of the well and the static water level in it (the distance at which the water mirror is located from the surface of the earth when the pump is turned off). For example, there is a well 50 m deep with a static level of 20 m; thus, the depth to the bottom is 50 – 20 = 30 m, and if you want to lower the pump to the very bottom, the maximum immersion depth must be at least 30 m — otherwise too high water pressure may damage the unit.
Mechanical impurities
The largest amount of mechanical impurities in the pumped water, which the pump can handle normally. When used with dirty water, this parameter should be taken into account along with the maximum particle size (see above): if the impurity content is too high, the pump may fail even if the individual particle size does not exceed the norm.
Suction system
— Single stage. Suction system with one impeller or similar element. Although this design loses to multistage in terms of efficiency and power, at the same time, its characteristics are quite enough for most entry-level and mid-level pumps; at the same time, single-stage units are simpler and cheaper.
— Multistage. This suction system consists of several impellers (or other similar parts that directly provide suction). Such pumps are noticeably superior to single-stage ones, they provide powerful pressure and are less sensitive to impurities. At the same time, multistage systems are quite expensive.
Max. liquid T
The highest suction water temperature at which the pump can operate normally. For deep well pumps, the water temperature is also important because the pump is constantly immersed in water during operation, and the liquid provides cooling. Therefore, in modern models, performance indicators are usually low — less than 30-35 °C. However, the temperature in artesian wells, usually, is much lower (the only exceptions are regions with thermal waters, but specific equipment is used there).
Power consumption
The power consumed by the pump motor during operation. A more powerful engine can provide more head and performance, but these parameters are not directly related: two models of similar power can differ markedly in practical characteristics. Therefore, this parameter is secondary, and more or less unambiguously it describes only the class of the unit as a whole — powerful engines are typical for high-end performant models. But what this characteristic directly affects is the actual power consumption; and with it, in turn, are connected not only to electricity bills but also connection requirements.
Overheat protection
To avoid overheating of the engine, deep well pumps are equipped with a special thermal relay. When it detects a heating temperature above the norm, it automatically turns off the motor, preventing it from failing.