What is a pump rotor. Glandless pumps Dry circulation pump

When planning home heating, in addition to the power of the heating boiler and the location of radiators, special attention is paid to the movement of the coolant. If the area of ​​​​the room is significant, then natural circulation will be ineffective, which will negatively affect the efficiency of such a system. To increase the efficiency of space heating, a pump is additionally installed in the pipeline, which provides forced circulation of the liquid. Since there are different types of circulation pumps, the choice of model is made taking into account the performance characteristics that are most suitable for specific conditions.

Purpose of circulation pumps

The principle of operation of a standard closed-type heating system is quite simple. The boiler heats the water that passes through the radiators, giving off the accumulated heat. In the case of natural circulation, it is very important to be accurate in the design, maintaining a certain angle of inclination of the pipeline. However, due to the low speed of the coolant, it quickly cools down, and cold liquid returns to the boiler, forcing it to constantly work at full load.

To eliminate this disadvantage, different types of circulation pumps are used. Their purpose is to create a coolant pressure necessary to ensure uniform distribution of heat between all elements of the system. First of all, it helps to reduce the requirements for compliance with slopes and cross-section of the pipeline. At the same time, the difference in the temperature of the liquid at the outlet and inlet of the boiler is only a few degrees, which significantly reduces the load on the heating equipment and reduces energy costs.

Types of circulation pumps

The main structural elements of such devices are:

  • body made of stainless steel;
  • electric motor;
  • impeller (impeller) mounted on the rotor shaft.

When the blades rotate, centrifugal force arises, as a result of which the required pressure is formed at the outlet pipe, and the liquid is injected into the pipeline. The difference between different types of circulation pumps for heating lies in the type of rotor, which has two varieties.

"Wet" rotor

A feature of the "wet" type devices is the location of the impeller with the rotor directly in the working environment. At the same time, the electrical part is reliably sealed thanks to a metal cup that separates the stator and rotor.

The fact that the rotor is constantly in the aquatic environment provides it with continuous cooling and lubrication of parts. At the same time, it is possible to absorb almost all vibration sounds, which makes these devices almost silent. It is this property that has become the reason for the great popularity of "wet" type devices in individual heating systems.

The disadvantage of such devices is the low efficiency (< 50%), что связано с невозможность надежной герметизации ротора при увеличении его диаметра. Поэтому их редко используют в случае большой протяженности трубопровода, когда требуется повышенная производительность.

"Dry" rotor

In this type of circulation pump, the rotor does not come into contact with water, and the working part is well insulated with special protective rings. This allows painlessly increasing the dimensions and power of the engine for pumping a significant amount of coolant. The advantage of such devices is the efficiency, reaching 80%, and the disadvantage is the high level of noise generated during operation.

In turn, these devices can be performed in the following versions:

  • Cantilever - have an axial inlet and a radial outlet. The electric motor housing is equipped with independent attachment points and is installed on the foundation plate.
  • Vertical (in-line) - the inlet and outlet pipes are located on the same axis and have the same conditional passage. The motor of the device is located in a vertical position.

Which type to choose

The question of choosing the type of circulation pump for heating is a matter of the scope of the device, its performance, price and noise requirements.

Scope of application

A wet rotor pump is not recommended for installation in an open system, such as DHW. Because in this case, the water, which acts as a lubricant, may contain various impurities, including sand. As a result, micron gaps between the rotor and the insulated stator will quickly become clogged, and the device will fail after six months or a year of such operation. In closed systems, on the other hand, such devices can function without failure for a long period without any human intervention.

Performance and price

If the required pressure for the normal functionality of a closed system is up to 10 m, then it is more expedient to use a "wet" rotor, which, with a capacity of 25-30 m³ / h, often costs less than a "dry" counterpart.

With an increase in pressure requirements, the cost and size of a “wet” type apparatus will be higher than that of a “dry” one, and in this case it is more profitable to give preference to the second option. In addition, given the higher efficiency of the "dry" rotor, it will consume less electricity with the same pressure and performance parameters.

For high performance systems, a dry rotor is the preferred option.

Noise level

As already noted, the "wet" type of circulation pump has a reduced noise level, which cannot be said about models with a "dry" rotor. In this case, the extraneous sound comes not only from the operation of the pump, but also from the rotation of the fan, which cools the electric motor. Therefore, "dry" devices are usually installed in separate rooms, where the noise level will not bring any discomfort to the residents of the house. In the case of installing the device directly in a residential area, it is more expedient to choose a less noisy option.

The low noise level of "wet" pumps plays a decisive role in the design of individual heating systems

It should be noted that even if you know what circulation pumps are and what you should pay attention to when choosing, it is better to consult with specialists before purchasing. Only a professional with extensive experience in designing such systems will help you choose the best type of equipment depending on the heating scheme.

Video: choosing a pump for heating

Art. 99347072

UPA15-120 AUTO
Application
UPA compact booster circulation pumps are designed to increase the pressure in existing cold and hot water supply systems in private houses. First of all, they are used to create pressure in front of water heaters (geysers and instantaneous water heaters), washing machines and dishwashers. UPAs can also be used to increase water pressure in showers or other taps.
Suitable for both cold and hot water up to 95°C.
Possibility of boosting water for several points at the same time (1-4 taps), which makes it suitable for apartments with a shared water supply and for single-family houses, as well as for:
- Urban areas with low water pressure during peak hours of drawdown.
- Apartments with a common low-pressure water intake.
- Rural areas with low water pressure.
Features and Benefits
The new built-in and patented flow switch automatically starts the pump when the tap is turned on, thus increasing the water pressure. When the tap is closed, the flow sensor stops the pump immediately.
The compact design of the UPA 120 is ideal for mounting even where space is limited.
The built-in flow sensor automatically starts and stops the pump as required to provide the required water pressure.
The UPA 120 with its new integrated flow sensor is very easy to install.
The high-tech wet rotor pump UPA 120 runs smoothly and silently, which is important for its use in private homes.

Circulation pump COMFORT 15-14 BXT PM 1x230V 50Hz art. 99279864 Grundfos

Art. 99279864

The Grundfos COMFORT 15-14 BXT PM circulation pump is required to circulate hot drinking water through a boiler in houses and cottages. By installing such a pump, you will not waste time and water waiting for hot water to come out of the tap. High energy efficiency of the pump is provided by a permanent magnet motor and a temperature control mode. In this version, the pump is supplied with a non-return valve and a cut-off valve. Available operating modes in the COMFORT 15-14 BXT PM pump: Continuous mode The pump runs continuously. Temperature control The pump turns on and off to keep the water hot. The value of the maintained temperature is determined by the internal algorithm. The pump uses an internal temperature sensor.
Specifications:
Pump type: Surface.
Pump type: Circulating.
Max. consumption: 0.5 m3/h.
Max. head: up to 1.2 m.

Body material: Brass.

Rotor type: “wet”.
Operating mode: constant and variable.
Mounting length: 110 mm.
Mains voltage: 1 x 230 V.


Water Quality: Pure
Protection class: IP 44.
Length: 154 mm.
Width: 84 mm.
Height: 110 mm.

Circulation pump COMFORT 15-14 BT PM 1x230V 50Hz art. 99279863 Grundfos

Art. 99279863

The Grundfos COMFORT 15-14 B PM circulation pump is required to circulate hot drinking water through a boiler in houses and cottages. The water in the system will always be hot. Now you won't waste time and water waiting for hot water to come out of the faucet. The PM version uses a permanent magnet motor for unsurpassed energy savings.
Specifications:
Pump type: Surface.
Pump type: Circulating.
Max flow: 0.5 m3/h.
Max. head: 1.2 m.
Pump installation: Horizontal.
Body material: Brass.
Connection connector diameter: 1/2".
Rotor type: “wet”.
Operating mode: permanent.
Mounting length: 80 mm.
Mains voltage: 1 x 230 V.
Maximum working pressure: 10 bar.
Permissible temperature of the pumped liquid: from 2°C to 95°C.
Water Quality: Pure
Protection class: IP 44.
Length: 144 mm.
Width: 84 mm.
Height: 80 mm.

Circulation pump ALPHA3 32-80 180 G 2 1x230V 50Hz with frequency converter art. 99371987 Grundfos

Art. 99371987

ALPHA3 32-80 180.




Characteristics













constant curve mode.





Circulation pump ALPHA3 32-60 180 G 2 1x230V 50Hz with frequency converter art. 99371985 Grundfos

Art. 99371985

ALPHA3 32-60 180.
Highly efficient rotary circulation pump designed for the circulation of liquids in heating systems. The World Class Energy Efficiency Index (EEI) well below the ErP benchmark results in significant energy savings.
ALPHA3 has a built-in Bluetooth radio and is fully controlled by a smart device via the Grundfos GO Remote app. It provides step-by-step assistance in pump setup, maintenance and commissioning.
ALPHA3 links directly to the Grundfos GO Balance app, which allows installers to perform quick and easy hydraulic balancing.
The AUTOADAPT function built into radiator and underfloor heating mode continuously adjusts the pump performance according to the actual heat demand, i.e. the size of the system and the changing heat demand throughout the year. The AUTOADAPT function will find the setting that provides optimal comfort with minimal energy consumption. It also makes commissioning fast, safe and easy.
Characteristics
Radiator mode with AUTOADAPT is an easy choice for two-row radiator heating systems.
Floor mode with AUTOADAPT is an easy choice for underfloor heating systems.
Combined radiator and floor operation for systems with a combination of heating systems.
In calendar and summer mode, the real time clock allows you to choose when the pump should run rather than save energy.
Simple user interface - the pump is fully controlled from the Grundfos GO Remote app.
Alarm and warning log using Grundfos Go Remote.
No external motor protection required, reducing installation time
High torque starting improves starting in harsh conditions.
Dry running protection during start-up and normal operation.
Maintenance-free thanks to the rotor design and the use of reliable components.
The ALPHA plug makes wiring quick and easy.
The pumps are equipped with insulating shells to minimize heat loss in heating systems.

In addition, the pump also has three control modes with gradual setpoint adjustment, which allows you to adjust the pump setting according to the set duty point:
proportional pressure control;
constant pressure control;
constant curve mode.
The display shows the actual power consumption in watts or the actual consumption in m3/h. The LEDs show the actual operating status.
The design of the pump and the selected materials contribute to a long service life.
The pump removes air from itself into the system, which contributes to easy commissioning. Compact design with pump head with integrated control box suitable for most common installations.
The pump and motor form a single unit without a shaft seal. The bearings are lubricated by the pumped liquid. These design features ensure maintenance-free operation.
The pump housing is made of cast iron. The pump body and pump head are cataphoretic coated for improved corrosion resistance.
The motor is a permanent magnet synchronous motor with high efficiency.
The pump speed is controlled by a built-in frequency converter built into the control box.
The benchmark for the most efficient circulators is EEI ≤ 0.20.

If, in the case of choosing a pump, the question arose of which is better - a pump with a wet rotor or a dry one, then we will try to deal with such units using the example of circulation pumps. It is known that such equipment is successfully used to create excellent and uninterrupted circulation of the coolant in the heating system of a private house.

In working condition, a pump with any type of rotor pumps a volume of liquid through the pipes, forcing it to move constantly forward. As a result of such an impact on the coolant, we have the following advantages:

  • Constant temperature indicator of radiators in all parts of the heat supply system;
  • The absence of air locks in the system, which means the elimination of the possibility of water hammer in it;
  • Saving family money on fuel or electricity consumption for heating the coolant (now you do not need to intensively fire the boiler so that the desired water temperature reaches the radiators in the back room of the house and warms it up). Glanded or dry rotor pumps will make everything faster and more productive.

Important: pumps with rotors of all types have two openings in their design: suction and discharge. Thus, the unit performs its work, moving it along a closed circuit.

Circulation pumps have a device similar to drainage pumps. The pump housing with a dry or wet rotor is most often made of durable alloys such as brass, cast iron, stainless steel or bronze. Such metals perfectly interact with water at high temperatures or with aggressive media (in the case of a drainage rotor).

The rotor itself is made from either durable stainless steel or ceramic. And the working unit (wheel with blades) is placed on the rotor shaft.

The principle of operation of such a device is to create centrifugal force inside the pump and looks like this:

When turned on, the rotor drives the impeller wheel, which rotates fast enough to create a pressure drop in the pump chamber. This encourages the flow of water into the tank. Further, the water that has entered the chamber increases the pressure and, at the same time, is pressed against the walls of the internal reservoir of the pump. As a result of this difference, water is pushed out into the outlet. The cycle repeats over and over until the unit is turned off.

Division of pumps with a rotor into types


All pumping equipment with a rotor can be divided into two types:

  • Units with a "wet" rotor;
  • Pumps with a "dry" rotor.

In the first case, we are talking about a mechanism whose rotor does not have direct contact with the pumped water. The isolation of the rotor in the pump mechanism is supported by special ceramic or metal seals in the form of rings. They protect the rotor from direct contact of the nodes with the pumped medium. But here the principle of operation of a device with a wet rotor is that between the protective rings rubbing against each other there is a thin, barely noticeable water layer. It helps to maintain the pressure difference in the heating system and in the working chamber, which means that it ensures the tightness of the rotor compartment. At the same time, at the moments of operation of the ring, the seals rub against each other more strongly, which ensures even greater tightness of the device.

Important: circulation units for heating or air conditioning systems with a "wet" rotor can be either single-phase or three-phase. That is, such pumps can be used both at home and in a large production or industrial enterprise.

Thanks to precisely these principles of operation, the unit with a “wet” rotor has a number of advantages:

  • Low noise level when pumping water through the system;
  • Modest weight and small dimensions;
  • Possibility of long-term operation without stops;
  • Economical power consumption;
  • Ease of installation, configuration, maintenance and repair.

At the same time, monoblock devices with a “wet” rotor are more popular with modern consumers.

Important: but along with all the listed advantages, the efficiency of a pump with a “wet” type rotor is significantly lower and is about 55%. Thus, it is best to use such a mechanism in houses with a small area, where the closed circuit of the heating system has a small length.

If we talk about water pumps with a "wet" type rotor, then here the devices will be slightly inferior to their counterparts with a "dry" rotor. But this applies only to surface aggregates.

Important: a prerequisite for the high-quality operation of a pump with a “wet” rotor and compliance with the principles of pumping water is the correct installation of the unit on the circuit. Here, the equipment shaft must be located strictly horizontally relative to the closed circuit of the heating system. Only in this case, a high-quality flow of fluid to the bearings for lubricating the working units will be ensured through the sleeve.

Dry Rotor Pumps


For all their productive capacity, units of this type have a number of disadvantages:

  • High noise level in operation.
  • The need for constant monitoring of the quality of the processed medium, since pumps with a "dry" rotor do not tolerate the presence of impurities in the water or air molecules. Such "neighbors" are able to break the tightness of the sealing rings in the mechanism.

At the same time, the entire range of pumps with a "dry" rotor is divided into three types:

  • Block devices;
  • Vertical aggregates, in which the engine is in a vertical position, and both nozzles are located on the same axis;
  • Console (horizontal), in which the engine is mounted horizontally, and the nozzles are perpendicular to each other.

Pump selection rules: dry or wet rotor


In order for the heating system to work as efficiently as possible, it is necessary to choose the right pump in accordance with the parameters of the house and the characteristics of the heating system. Only in this case and subject to the correct installation of the mechanism in compliance with the principles of its operation, the heat in the house will be of high quality and long lasting.

So, when choosing a pump, consider the following points:

  • The total area of ​​\u200b\u200bthe house and the length of the closed circuit of the heating system;
  • The number of radiators for the entire length of the heating system;
  • The presence of "warm floor" systems, etc.;
  • Quality and density of window metal-plastic packages;
  • Insulation of walls, ceiling or roof in the house.

Important: calculations of the required amount of heat should be carried out only by competent heat engineers who will take into account all the important nuances and recommend a pump with nominal pressure characteristics for your room.

It is important to consider that if you choose a pump for a heating system that already exists, but needs to be improved, then it is better to buy an adjustable unit. This device perfectly adapts to the operating parameters of a given circuit.

Mounting principles for units with any rotor


In order for the operation of the circulation equipment to be of high quality, it is better to invite specialists to install it. But if you want to install the pump yourself, then follow these rules:

  • The installation of the unit is carried out at the boiler from the reverse type. That is, where the water that has passed the entire closed circuit of the system returns again. But this rule applies to premises whose area does not exceed 150-200 m2.
  • It is important to follow the location of the arrow on the pump housing when installing it. The arrow should look in the direction of the movement of warm water through the system.
  • All flanged and threaded joints must be treated with sealant to avoid possible leaks.
  • If you are dealing with a reverse circulation heating system, then it would be useful to install a bypass - a piece of pipe, which, in case of repair of the unit, will be able to close the heating circuit after removing the pump.

Popular Wet Rotor Pump Models

The most popular units for transporting water with wet rotors are products manufactured by German, Danish and Canadian companies. A special place among the product range is occupied by the Wilo pump.

The devices have a threaded connection and are equipped with a speed control system to control the performance and power of the pump. Wilo units are used in heating and air conditioning systems, as well as in cold water circulation systems in factories.

Grundfos pumps


Another leader in the modern Russian and world markets of pumping equipment. These pumps are highly efficient and reliable. Thanks to careful assembly from scrupulous Danes, the units work without failures and breakdowns for a long time.

The salient features of these mechanisms are:

  • Absolute inertness to water and anti-corrosion properties of the metal;
  • No need for frequent preventive maintenance and repair (wet rotor does its job);
  • Reliable tightness of the case.

Important: Grundfos pump casings are equipped with a special heat-shielding casing, which prevents the risk of possible user burns.

It was believed by many that for domestic performance it is necessary to take circulation pumps with a wet rotor. Dry rotary circulation pumps were used for industrial use.

There was an opinion that pumps with a dry rotor were too large and very noisy. However, large manufacturers began to increasingly produce household models of circulation pumps with a dry rotor.

Dry rotor circulation pumps are used in industry.

In the domestic version, circulation pumps with a wet and dry rotor are used. For production needs, pumps with a wet rotor are not used, since they can be produced with a power of up to 3 kW and they are not widely used.

Advantages of circulation pumps with a dry rotor of industrial design: the quality of the coolant is not important for them, they have good maintainability. The disadvantage of these pumps is that they are large, very noisy, so they are installed in separate rooms, they consume a lot of electricity.

As for the household version of the pump with a dry rotor, its advantages:

has a higher efficiency;

for him, the purity of the coolant is not important;

has good maintainability, and spare parts are cheaper than pumps, having a wet rotor;

almost does not differ in size from the wet rotor counterpart.

The downside is a lot of noise during operation and the need for regular replacement of the mechanical seal.

The disadvantages of circulation pumps with a dry rotor are pluses for a pump with a wet rotor: noiselessness, does not have a mechanical seal. The disadvantage is that the quality of the coolant is of great importance during operation. The worse the quality of the pumped liquid, the faster the pump can fail.

Considering all the minuses and pluses of the considered pumps, we can draw the appropriate conclusions. If the quality of the coolant is not important to you, then it is better to choose a pump with a wet rotor, but it is not known what will happen to the rest of the heating system.

If you want everything to work smoothly, it is better to use a dry rotor motor, but you also need to take care of the quality of the coolant.

As for the noise, everyone decides for himself, because the pump does not often come into view. The efficiency is not so important, since the percentage difference is small, but the absence of the need to replace the mechanical seal is a big plus.

But maintenance should be carried out regularly, together with an inspection of the entire heating system by a specialist.

Dry rotor pumps are used to pump liquids with high pressure. They are best suited for supplying coolant and aggressive media. Unlike wet rotor pumps, in these pumps the liquid does not come into contact with the motor.

Another difference from glandless pumps is the way the pump housing/shaft is insulated. This is achieved using stuffing box or sliding mechanical seals (STU).

Standard dry rotor pumps typically use three-phase, constant speed motors. They are usually controlled via an external electronic speed control system. Today, dry rotor pumps are available with an integrated electronic speed control unit, which, thanks to modern technology, can also be installed on motors with high output power.

The overall efficiency of pumps with a dry rotor is significantly higher than that of pumps with a wet rotor. Dry rotor pumps are divided into three main types:

In-line pumps
Pumps in which the suction and discharge pipes are on the same axis and have the same nominal bore are called in-line pumps. In-line pumps are equipped with standard air-cooled flange motors. This type of pump is considered the most suitable for building systems requiring high power output. These pumps are installed directly on the pipeline. In this case, the pipeline is fixed with brackets or the pump is installed on a foundation or a separate bracket.

Block pumps
Block pumps are low pressure, constant speed centrifugal pumps with a standard air-cooled electric motor. Fluid enters the pump in an axial direction and exits in a radial direction. Brackets or motor supports are standard on the pumps.

Console pumps
These centrifugal pumps have an axial inlet and a radial outlet of liquid from the pump. The pump and motor have independent attachment points. Therefore, they are installed on a foundation slab.

Depending on the fluid and operating conditions, they can be equipped with a STU or a stuffing box seal. The nominal passage of such pumps is determined by the discharge pipe. The suction pipe has a larger conditional passage.

Shaft seal
The shaft can be sealed (as standard or as an option in the case of cantilever pumps) against the atmosphere with a CTU or gland seal. Below is a description of these two types of seals.

STU pump with a dry rotor

Sliding mechanical seals
The mechanical seal is based on two rings with carefully polished surfaces. They are pressed against each other with a spring and work together. STUs are dynamic seals and are used to seal a shaft rotating in a liquid at high operating pressures. STU consists of two polished wear rings (eg silicone or graphite), which are pressed against each other by axial forces.

One ring (dynamic) rotates with the shaft, while the other ring (static) is fixed in the housing. A thin film of water forms between the sliding surfaces, serving as a lubricant and cooling agent. Depending on the mode of operation of the pump, several types of friction of the mating surfaces are possible: mixed friction, boundary friction or dry friction, the latter (occurring in the absence of a lubricating film) causes immediate destruction of the surfaces.

The service life depends on the operating conditions such as the composition and temperature of the working fluid.

Stuffing box seals
Good quality synthetic fiber yarns such as Kevlar® or Twaron®, PTFE, porous graphite yarn, synthetic mineral fiber yarn, and natural fibers such as hemp, wadding or ramie are used as materials for stuffing boxes.

Material for stuffing boxes is produced in the form of threads or compressed coils, in dry form or with special impregnation, depending on the purpose. If the material is purchased in the form of threads, you first need to form a ring and give it a shape. Then, the stuffing box ring is wrapped around the pump shaft and tightened with a ferrule.

Mounting types

Permissible mounting methods
In-line pumps are designed for horizontal and vertical installation directly on the pipeline.
Sufficient space must be left to dismantle the motor, pump elements.
When connecting the pipelines, stress and weight of the pipelines must not be transferred to the pump, and the pump must be installed on supports (if any).

Prohibited mounting methods
Mounting with the motor and terminal box pointing downwards is not permitted.
If the motor power exceeds a certain level, the manufacturer should be consulted before installing the pump in a horizontal position.


- Section of high pressure centrifugal pump
- Characteristics of high pressure centrifugal pump

High pressure centrifugal pumps

These pumps are usually multistage. The flow rate of the pump depends on the size of the impeller and other factors. The pressure in high pressure centrifugal pumps is achieved by using several impellers installed in series. Kinetic energy is converted into pressure partly in the working, and partly in the straightening apparatus.

Due to the possibility of varying the number of stages, high-pressure centrifugal pumps develop a higher pressure compared to low-pressure single-stage centrifugal pumps.

Some pumps have up to 20 stages. Thus, they can provide heads up to 250 m. Almost all high pressure centrifugal pumps that we have described belong to the dry rotor pump family. However, recently manufacturers have been successfully equipping them with wet rotor motors.

Special instructions for block pumps
Block pumps must be installed on suitable foundations or brackets.
Installation of a block pump with the motor and terminal box pointing downwards is not allowed. All other mounting methods are considered acceptable.
For details on installation methods, see the installation and operating instructions.