As technology develops, it improves and develops newest types heating systems. Nowadays, circulation systems with dry and wet rotors have become widespread in many markets, due to their qualities such as operational efficiency, convenience and reliability of operation.
You can see a circulation pump for heating systems in almost all stores where it is sold. household appliances, in the markets or check out the characteristics on our resource.
Advantages
- Unlike heating systems that do not include this mechanism, the device can turn on in a matter of minutes and begin to perform its functions. Fast system overclocking allows for short time heat the room.
- The presence of this equipment in the system increases the efficiency of the heating circuit in general and ensures high efficiency.
- The use of a circulation pump in the system wiring guarantees reliable and trouble-free operation of heating rooms in general. These models are also easy to use.
- The pump is very convenient. It can be placed in any area of the room and from the right place it will provide high-quality air circulation.
Forced circulation scheme
Types of circulation pumps
There are many types and types of heating circulation pumps. The article will discuss the most common types of pumps.
Circulation pump with a wet rotor - the impeller and rotor are positioned so that they immediately begin to process the liquid. Impeller separated from the stator made of stainless steel cup. The working shaft can be made of either metal or ceramic. The liquid processed by the rotor simultaneously maintains the temperature of the engine, cooling it, and serves as a lubricant for rubbing parts.
With wet rotor
The assembly of pumps with a wet rotor is carried out according to a special principle called modular. Depending on the performance and pressure, the appropriate modules are selected. This design simplifies repairs when only the module is replaced in the event of a breakdown. It is very important to keep in mind that it is not necessary to remove air from the volute of a wet rotor. The air is removed automatically by the rotor itself.
And the second type of equipment is a dry rotor circulation pump. The dry rotor takes its name from the design and operating principle of the device. Structurally, the impeller and rotor do not come into contact with the water being treated. This type Circulation pumps are used to work with large volumes of water in heating.
With dry rotor
Unlike the above type of pump, the mechanism with a dry rotor includes special seals. They are located midway between the drive and the pump housing. The formed film of water between the surfaces during operation seals the pump. Depending on working operation, rings can be made of ceramics, stainless steel, agglomerated carbon. Heating pumps with a dry rotor are available with flanged motors and motors connected by a coupling.
Choice
Which is the best circulation pump for a heating system? When heating, the main attention is paid to such a parameter as the heat generated, which the device will provide to the room. In organizations where they evaluate the parameters of a device, the data is evaluated using special programs, then after the calculation, real calculations are issued.
Product design
One of the popular methods for choosing a pump is to estimate the area of the room that the pump can heat. According to European standards, houses with two or fewer apartments require a heating power of 100 watts per square meter. And for houses with many apartments 70 watts per meter. And depending on the quality of thermal insulation, the power parameters depend. If the thermal insulation is good, then 30 - 50 watts per square meter is needed.
For poor quality thermal insulation, high power ratings are taken.
For our harsh climate The following data corresponds:
- For two-story house at an air temperature of minus 25 degrees - 173 watts per square meter, if minus 30, then 177 watts per square meter;
- for a building with more than two floors, 97 and 101 watts per square meter are suitable, respectively.
If you have some knowledge of calculating pump power, you can correctly calculate and calculate which circulation pump is needed for your home.
Installation
Installing a circulation pump in a heating system will not take much time if you have the necessary tools and the necessary skills:
- keys in a set with sizes from 17 to 36;
- bypass, filter, check valve;
- "American" carvings.
To connect the pump to the heating system, follow the following guidelines:
Installation options
- Technical parameters of the pump, which are calculated as shown above;
- Connecting the mechanism to the return pipelines will ensure the operation of devices with chilled water. This will extend the service life of the products. also connect to the return pipeline;
- With the heating boiler turned off, pump pipe the inlet and outlet valves are closed. Then the product should be installed in a horizontal position, tightened using “American” nuts. Vertical equipment will create excess noise during operation.
Important advice: when installing a gasket, it is better to choose one made of paranite, because rubber ones will become unusable when the temperature rises.
- Installing a circulation pump will be an addition if the circulation is natural. Here you should also purchase a filter and “American” nuts with a diameter suitable for the device. For closed wiring, a check valve will be needed, but for open ones it is not needed at all;
- When installing, do not forget to install taps, which will be useful when repairing the system. The bypass line, when installed, will allow circulation to continue when the device is removed and even in the absence of electricity.
Conclusion
It is worth noting here that it is best to choose equipment from well-known manufacturers. Circulation pumps powered by 12 volts will ensure reliable operation. As well as additional emergency batteries or diesel generators, they will be useful when emergency shutdown electricity. For big houses products with lower productivity are suitable.
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Pump installed in the heating system.
A wet rotor circulation pump is an element of the heating system designed to circulate coolant through the heating circuit.
Design
The pump device consists of a cast iron casing in which an electric motor rotates a composite wheel mounted on a shaft. The wheel consists of two disks, between which curved blades are located radially. The coolant enters the wheel through a hole in the lower disk.
In wet running models, all moving parts (including the motor rotor) are in contact with the coolant, which will act as a lubricant/cooler for the ceramic (graphite) end bearings and the rotor itself. In this case, the stator is isolated from the coolant using a metal partition with sealing gaskets.
The design of “wet” pumps is more complex than the design of pumps with a dry rotor, so their cost with equal characteristics will always be higher.
Note! As a rule, circulation pumps have 3 speeds, which are switched by turning the regulator to one of three speeds. At the same time, at minimum speed, the pump consumes approximately 2 times less electricity compared to maximum speed.
Installation
Installation of a circulation pump for a heating system, like any other heating equipment, must be carried out in accordance with the installation instructions, as well as in accordance with the heating system design. However, there are some general requirements for installing a circulation pump:
- The direction of movement of the coolant must coincide with the direction indicated by the arrow on the body;
- The pump must be installed between the boiler and the heating circuit (but not between the radiators). It can be installed on both the supply and return lines, but preference is given to the return pipeline. The specific installation location must be easily accessible, because during operation, it may require maintenance or replacement in case of failure;
- Do not place thermal insulation on the engine compartment;
- After a circulation pump with a wet rotor, it is recommended that in case of an emergency, it will prevent the coolant from moving in the opposite direction;
- Before and after the pump it is necessary to install shut-off valves. In case of breakdown, shut-off valves will allow you to remove/replace the device without draining the coolant from the system;
- It is recommended to install anti-vibration inserts before and after it. This does not apply to small pumps;
- After installation, the housing should not experience pressure from the connected pipes. When installing a circulation pump on relatively long pipelines, it is recommended to fix both the pipes themselves and the pump. This will reduce negative impact vibrations;
Note! Installation before the pump is required mesh filter, which will reduce the likelihood of damage to mechanisms by various mechanical particles (sand, rust, scale or other sludge). In addition, its correct location will allow it to avoid contamination by such particles; it should not be installed in the lowest section of the heating system.
- Installing a wet rotor circulation pump at the highest point in the system can result in air being frequently drawn into it. If, nevertheless, air has accumulated in it, it is necessary to slowly unscrew the air bleed screw using a screwdriver or a coin and allow the coolant to flow out for 2-4 seconds;
- To support the circulation pump for the heating system, it is prohibited to use wooden (or made from any other flammable material) supports, because during operation, the housing can heat up to a temperature of +124°C, so such supports may catch fire;
Note! You should always remember that the casing of a running pump heats up to high temperatures and there is a possibility of burns upon contact with it.
- If the heating system has just been installed, before operation it is recommended to rinse it with water at a temperature of 80-85°C, then drain the water and only then fill the system with “permanent” coolant. This will remove any contaminants that may have entered the heating circuit during installation work;
- The motor shaft must always be in a horizontal position.
Heating systems are divided into systems with natural (gravity) and forced circulation. In systems with forced circulation, the installation of a circulation pump is required. Its task is to ensure the movement of coolant through the system at a given speed. And in order for it to cope with its task, you must choose the right circulation pump.
Purpose and types
As already mentioned, the main task of the circulation pump is to provide the required speed of coolant movement through the pipes. For systems with forced circulation, only under such conditions will the design capacity be achieved. During operation of the circulator, the pressure in the system increases slightly, but this is not its task. It's more likely side effect. There are special ones to increase the pressure in the system.
There are two types of circulation pumps: dry and wet rotor. They differ in design, but perform the same tasks. To choose what type of circulation pump you want to install, you need to know their advantages and disadvantages.
With dry rotor
It got its name due to its design features. Only the impeller is immersed in the coolant; the rotor is in a sealed housing; it is separated from the liquid by several sealing rings.
The design of a circulation pump with a dry rotor - only the impeller is in the water
These devices have the following properties:
- They have high efficiency - about 80%. And this is their main advantage.
- Requires regular maintenance. During operation, solid particles contained in the coolant fall on the sealing rings, breaking the tightness. Maintenance is required to prevent depressurization.
- Service life is about 3 years.
- When working they publish high level noise
This set of characteristics is not very suitable for installation in heating systems of private houses. Their main advantage is high efficiency, which means lower energy consumption. Therefore, in large networks, circulation pumps with a dry rotor are more economical, and are mainly used there.
With wet rotor
As the name implies, in equipment of this type, both the impeller and the rotor are located in the liquid. The electrical part, including the starter, is enclosed in a sealed metal cup.
Wet rotor pump design - only the electrical part is dry
This type of equipment has the following properties:
- Efficiency is about 50%. Not the best best indicator, but for small private heating systems this is not critical.
- No maintenance required.
- Service life is 5-10 years depending on the brand, operating mode and condition of the coolant.
- During operation they are almost inaudible.
Based on the above properties, choosing a circulation pump by type is not difficult: most people opt for devices with a wet rotor, since they are more suitable for working in an apartment or private house.
How to choose a circulation pump
Each circulation pump has a set of technical characteristics. They are selected individually for the parameters of each system.
Selecting technical specifications
Let's start with the selection of technical characteristics. There are a lot of formulas for professional calculations, but to select a pump for the heating system of a private house or apartment, you can get by with average standards:
Selecting a circulation pump for heating following these rules is not difficult. Elementary calculations. But it must be said that these figures are statistical averages. If your house at some point differs greatly from the “average”, you need to make adjustments either towards increasing or decreasing technical characteristics. For example, you have insulated your house well, but the power of the previously purchased boiler turned out to be excessive. In this case, it makes sense to choose a pump with a lower capacity. In the opposite situation - the house is chilly in extreme cold - you can install a more efficient circulator. It will temporarily solve the problem (in the future you will need to either insulate or change the boiler).
Model selection
When choosing a specific model, pay attention to the graph with the pressure characteristics of the pump. On the graph you need to find the point where the pressure and productivity values intersect. It should be located in the middle third of the curve. If it does not fall on any of the curves (there are usually several of them, characterizing different models), take the model whose graph is closer. If the point is in the middle, take the less productive one (the one located below).
What else to pay attention to
In the technical characteristics of circulation pumps there are several more items that are worth paying attention to. First - permissible temperature pumped medium. That is, the temperature of the coolant. IN quality products this indicator ranges from +110°C to +130°C. In cheap ones it can be lower - up to 90°C (but in fact 70-80°C). If your system is designed as a low-temperature system, this is not a big deal, but if you have a solid fuel boiler, the temperature to which the coolant can be heated is very important.
It is also worth paying attention to the maximum pressure at which the pump can operate. In the heating system of a private house, it is rarely higher than 3-4 atm (this is for a two-story house), but normally it is 1.5-2 atm. But still, pay attention to this indicator.
Something else to pay attention to is the material from which the case is made. The optimal one is cast iron, the cheaper one is made of special heat-resistant plastic.
Connection type and size. The circulation pump can have threaded or flanged connections. The thread can be external or internal - appropriate adapters are selected for it. Connection sizes can be: G1, G2, G3/4.
It is also worth paying attention to the presence of protection. There may be dry-running protection. In circulation pumps with a wet rotor, it is very desirable, since the cooling of the motor occurs due to the moving medium. If there is no water, the motor overheats and fails.
Another type of protection is overheating protection. If the motor heats up to a critical value, the thermal relay turns off the power and the pump stops. These two features will extend the life of the equipment.
Manufacturers and prices
| Name | Performance | Pressure | Number of speeds | Connection dimensions | Maximum working pressure | Power | Housing material | Price |
|---|---|---|---|---|---|---|---|---|
| Grundfos UPS 25-80 | 130 l/min | 8 m | 3 | G 1 1/2" | 10 bar | 170 W | Cast iron | 15476 RUR |
| Caliber NTs-15/6 | 40 l/min | 6 m | 3 | external thread G1 | 6 atm | 90 W | Cast iron | 2350 rub. |
| BELAMOS BRS25/4G | 48 l/min | 4.5 m | 3 | external thread G1 | 10 atm | 72 W | Cast iron | 2809 RUR |
| Gilex Compass 25/80 280 | 133.3 l/min | 8.5 m | 3 | external thread G1 | 6 atm | 220 W | Cast iron | 6300 rub. |
| Elitech NP 1216/9E | 23 l/min | 9 m | 1 | external thread G 3/4 | 10 atm | 105 W | Cast iron | 4800 rub. |
| Marina-Speroni SCR 25/40-180 S | 50 l/min | 4 m | 1 | external thread G1 | 10 atm | 60 W | Cast iron | 5223 RUR |
| Grundfos UPA 15-90 | 25 l/min | 8 m | 1 | external thread G 3/4 | 6 atm | 120 W | Cast iron | 6950 RUR |
| Wilo Star-RS 15/2-130 | 41.6 l/min | 2.6 m | 3 | internal thread G1 | 45 W | Cast iron | 5386 RUR |
Please note that everything technical specifications presented for moving water. If the coolant in the system is a non-freezing liquid, adjustments must be made. You will have to contact the manufacturer for relevant data for this type of coolant. It was not possible to find similar characteristics in other sources.
Good afternoon, dear readers of the blog site
Dry rotor circulation pumps
Let’s continue the “Pumps” section by talking about circulation pumps for heating systems with a “dry” rotor. These pumps are divided into three groups: inline pumps, monoblock pumps and cantilever pumps. Unlike pumps with a dry rotor, the coolant does not come into contact with electric motor. These pumps are less sensitive to the presence of suspended particles and scale in the water. Circulation pumps with a dry rotor are used in systems with a large volume of coolant. This type of pump is used to seal the shaft. It consists of two parts: a movable and a stationary seal. The movable part is mounted on the pump shaft, and the stationary part is pressed into the pump housing. Graphite, ceramics, carbon, stainless steel, aluminum oxide, tungsten carbide and other materials can be used as materials for the end seal. The material used for seals depends on the type of coolant and its temperature.
Circulation pumps for heating with a “wet” and inline pumps with a “dry” rotor are available in both single and double. Double pumps are used for redundancy; if one pump fails, the second one comes into operation. Also, when in the coldest time of the year more heat is needed, and the performance of one pump is not enough, a second pump can be switched on. During severe frosts and peak loads, both pumps can operate, and when the temperature rises and there is no need to operate two pumps, one of them remains in reserve. This achieves energy savings due to the fact that lower power pumps can be used. As you know, according to SNiP, the heating system is calculated for the coldest five-day period of the year that may occur in a given region. Based on these calculations, the selection of boiler and pumping equipment. But usually the heating system is operated at maximum mode for about a month and a half. The rest of the time the heating system is used at 40 - 60% of its maximum power
Inline pumps
Heating pumps with a dry rotor Inline are pumps in which the suction and discharge pipes are on the same axis. These pumps have the same nominal bore and connection size of flanges on the suction and discharge pipes. The diameters of the pipes range from DN 32 – DN 100. Such pumps are installed directly on pipelines. When installing pumps on a pipeline, it is necessary to install temperature compensators to compensate for thermal expansion of the pipelines during operation of the heating system. Inline pumps are equipped with standard two or four pole asynchronous motors With air cooled and a speed of 2900 or 1450. These pumps use an impeller with reduced cavitation characteristics. Impeller Heating pumps with a dry rotor located directly on the motor shaft. Due to this design, these pumps operate quietly, without creating much noise or vibration. Inline pumps are used for pumping cold and hot water without abrasive substances in heating systems, hot water supply and air conditioning, in refrigeration and other installations for industrial and domestic use. The temperature range of the pumped liquid is from -20 to +140°C. The maximum operating pressure of such pumps is 16 bar. Maximum temperature environment 40°C.
Block pumps
These pumps are low-pressure, high-capacity centrifugal circulation pumps. Block pumps use standard two or four pole asynchronous electric motors air cooled. They have an axial suction and radial discharge pipe. As standard, the pumps are equipped with support angles and brackets for attaching them to the base. Monoblock pumps have a very wide range of applications and are used as: circulation pumps in heating and air conditioning systems, for supplying water in water supply systems, pressure boosters and fire extinguishing systems. For the food industry, monoblock pumps made of stainless steel, cast iron or bronze are used. a separate article will be devoted
Cantilever pumps
The peculiarity of these pumps is that the pump part and the engine have their own shafts and mounting units. During assembly, the pump and motor are installed on a common frame (bed), their shafts are centered and connected using a coupling. The nominal bore of such pumps is determined by the pressure pipe. The suction pipe always has a larger nominal diameter than the pressure pipe. Cantilever pumps are designed for pumping clean and slightly contaminated water without abrasive inclusions in heating, water supply and pressure boosting systems. Cantilever pumps are used in urban water supply, irrigation, drainage, public utilities, industry, etc. a separate article will also be devoted
Operating point
The selection of circulation pumps with a dry rotor occurs according to the same parameters as. The operating point of the heating system should be close to performance characteristics pump, based on performance and required pressure.
Operation and Maintenance
Like circulation pumps with a “wet” rotor, Heating pumps with a dry rotor It is not recommended to operate without water. When the pump is running, the movable seal begins to rotate relative to the stationary one. A thin film of water forms between the friction surfaces, which wets the working surfaces of the seals. There is a spring on the rotating part of the mechanical seal, which, as the working surfaces of the seal wear, constantly presses the moving part against the stationary one. Average term The seal service life is from 2 to 4 years, but under harsh operating conditions (frequent overheating, the presence of impurities and suspensions in the coolant), the service life is very sharply reduced. Dry running for pumps with a dry rotor is unacceptable and leads to damage to the working surfaces of the mechanical seal. The water film quickly evaporates, and overheating occurs, and then mechanical destruction of the rubbing parts of the seal.
Repairing the circulation pump in this case is a simple operation, but it must be carried out by specialists service centers for maintenance of this type of equipment.
Thank you and see you again.
If heating is required large premises with a total area of several hundred square meters system pressure autonomous heating with natural circulation (about 0.6 mPa) created by the heating heater is usually insufficient.
To solve this problem, you can go in two ways:
1. Build a closed system using large-caliber pipes, which are not cheap.
2. Turn on the circulation pump into the system.
The second option is economically more feasible. By improving the circulation of coolant in the system, heating efficiency increases significantly.
Circulating heating pumps are divided into two types:
1. With a wet rotor.
They are used in the heating system of private households, where the length of pipelines is not so long.
The pump rotor, equipped with an impeller, rotates inside the housing and accelerates the movement of the coolant. The liquid inside which the rotor rotates cools and lubricates the mechanism.
When installing a “wet type” pump, you should pay attention to the horizontalness of the shaft, then there will always be water inside the housing.
Advantages of glandless rotor pumps:
- almost silent;
- stepless switching of rotor speed;
- reliability in operation;
- long term services;
- no need for maintenance;
- ease of repair and adjustment of the pump;
- relative cheapness.
Flaws:
- low efficiency (not higher than 50%)
2. With a dry rotor. Used in heating systems of great length. O-rings are installed between the electric motor and the working part of the rotor, the service life of which is 3 years. There is no contact between the rotor and the coolant.
Advantages:
- high efficiency - about 80%;
Flaws:
- high noise level, which is why they are installed in a separate room equipped with sound insulation;
- the need to control the absence of suspended particles in the coolant and dust in the air surrounding the engine in order to avoid damage to the surfaces of the sealing rings, which can cause their damage and leakage.
When choosing the type and model of a circulation pump for a heating system, you should also take into account their performance, operating conditions, features of the coolant (its viscosity and density), recommendations and requirements of the manufacturer for installation and quality characteristics of the pumped liquid.
