Comparison Rudes 3S 0.8-30-0.37 vs Werk 3QGD 1.85-70-0.37

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.

The maximum head is the maximum height to which the pump can raise water during operation (the highest height of the water column that it can support). This parameter describes the pressure created during operation, but since the operation of well pumps is directly related mainly to lifting liquid to a great height, it is easier to use head data in metres than pressure data. However, if necessary, one can be easily translated into another — 10 m of pressure corresponding to a pressure of 1 bar.

When choosing a pump for this parameter, it is not necessary to chase a large pressure, but it is necessary to take into account several factors.

The first of these is the actual height to which the water must be raised; it can be determined by adding the immersion depth of the pump and the height of the highest draw-off point above the ground. The immersion depth is displayed taking into account the so-called dynamic water level in the well — i.e. distance from the surface of the earth to the water surface during continuous operation of the pump (this indicator is greater than the static level, since when the water is pumped out, its level decreases). The dynamic level is usually indicated in the well passport; the pump should be at least a metre deep underwater, plus a margin of 2 – 3 m should be taken as an adjustment for seasonal level fluctuations. Accordingly, for a well with a dynamic depth of 40 m, supplying a house with...an upper draw-off point of 6 m above the ground, the total height difference will be at least 40 + 6 + 4 = 50 m.

The second point is the hydraulic resistance of the system. Even with horizontal pipes, pressure is required to move fluid through them; usually, when calculating, it is assumed that for every 10 m of the pipeline, 0.1 bar, or 1 m of head, is required. For a water supply system inside an average house, resistance losses are about 5 m of head (0.5 bar). Accordingly, if in our example the house is located 10 m from the well, then the margin to overcome the resistance should be at least 1 + 5 = 6 m of head.

And the third point is the pressure at the points of water intake because the pump must not only “push” the water to the tap, but also provide pressure at the outlet. Here, the optimal values may be different depending on the situation. For example, let's take at least 1 atm (1 bar), which corresponds to 10 m of pressure.

Thus, in our example, the pump head must be at least 50 m (height difference) + 6 m (resistance) + 10 m (outlet head) = 66 m. Of course, this is a calculation for the most general case; in special situations, the formulas may differ, so it makes sense to refer to special sources for them.

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.

The basic principle or principles by which the suction action of the pump is carried out.

— 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).

— 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.

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.

The length of the standard power cable provided in the design of the pump.

Ideally, the length of this cable should not be less than the maximum immersion depth — this will ensure maximum ease of connection: the connection point of the cable to the mains will be above the water (in the best case, even outside the well), and you will not have to worry about insulation. At the same time, for several reasons, many pumps are equipped with rather short cords — about 1.5-2 m, and not long cables; in such cases, it is necessary to use special waterproof equipment.

A safety system in case of an overload of a deep well pump when its engine is running beyond its capacity. It can lead to engine failure or even fire. Overloading is usually prevented by thermal current relays introduced into the circuit of pumping equipment.

In this case, the country of origin refers to the country from which the product brand originates. A brand, in turn, is a general designation by which the products of a particular company are known in the market. The country of its origin does not always coincide with the actual place of production of the device: to reduce the cost of production, many modern companies transfer it to other countries. It is quite normal for products, for example, of an American or German brand, to be made in Taiwan or Turkey. Contrary to popular belief, this in itself does not lead to a decrease in the quality of the goods — it all depends on how carefully the brand owner controls the production. And many companies, especially large and "famous", monitor the quality very zealously — after all, their reputation depends on it. However, the range on the market is not so great. In addition to East European pumps, there are models from Italy and China.

The material from which the pump impeller is made.

A wide variety of materials are used in modern well pumps. However, the manufacturer, usually, chooses the option so that the strength, reliability, resistance to pollution and other key features of the wheel correspond to the required characteristics of the pump and its level as a whole. In addition, the same material may have several varieties that differ markedly in characteristics; this is especially true for technopolymers and thermoplastics, but most metallic materials such as stainless steel or brass also come in several grades. All this means that when choosing a pump, it makes sense to look first of all at performance characteristics, price category, reviews and other practically significant information, and the material of the impeller is of secondary importance.