Flamco pressure maintenance unit. Selection of AUPD for heating and cooling systems of high-rise buildings. Frequency control for all pumps SPL® WRP-A

Boost settings pressure SPL® are intended for pumping and increasing the pressure of water in the systems of domestic, drinking and industrial water supply of various buildings and structures, as well as in fire extinguishing systems.

This is a modular high-tech equipment consisting of a pump unit, including all the necessary piping, as well as modern system management, guaranteeing energy-efficient and reliable operation, with all the necessary permits.

Application of components from leading world manufacturers, taking into account Russian standards, norms and requirements.

SPL® WRP: Symbol Structure

SPL® WRP: composition of a pumping unit

Frequency control for all pumps SPL® WRP-A

The frequency control system for all pumps is designed to monitor and control standard asynchronous electric motors of pumps of the same size in accordance with external control signals. This system control provides the ability to control from one to six pumps.

The principle of operation of frequency regulation for all pumps:

1. the controller starts the frequency converter, changing the pump motor speed in accordance with the readings of the pressure sensor based on the PID control;

2. at the beginning of work, one variable frequency pump is always started;

3. The capacity of the booster installation varies depending on consumption by turning on / off the required number of pumps and parallel regulation of the pumps in operation.

4. if the set pressure is not reached, and one pump is operating at maximum frequency, then after a certain period of time the controller will turn on the additional frequency converter and the pumps are synchronized according to the speed (pumps in operation operate at the same speed).

And so on until the pressure in the system reaches the set value.

When the set pressure is reached, the controller will start decreasing the frequency of all running frequency converters. If for a certain time the frequency of the converters is kept below a predetermined threshold, the additional pumps will be switched off alternately at certain intervals.

To equalize the resource of the pump electric motors over time, the function of changing the sequence of switching on and off the pumps is implemented. It is also provided for automatic activation of standby pumps in the event of failure of workers. The choice of the number of working and standby pumps is made on the controller panel. Frequency converters, in addition to regulation, provide a smooth start of all electric motors, since they are connected directly to them, which allows avoiding the use of additional soft starters, limiting the starting currents of electric motors and increasing the service life of pumps by reducing dynamic overloads of actuators when starting and stopping electric motors.

For water supply systems, this means no water hammer when starting and stopping additional pumps.

For each electric motor, the frequency converter allows you to implement:

1. speed control;

2. overload protection, braking;

3. monitoring of mechanical load.

Mechanical stress monitoring.

This set of features allows you to avoid the use of additional equipment.

Frequency regulation per pump SPL® WRP-B (BL)

There can be only two pumps in the base of a pumping unit of the SPL® WRP-BL configuration, and control is realized only according to the principle of working-standby pump operation, while the working pump is always involved in operation with a frequency converter.

Frequency regulation is the most effective method regulation of pump performance. The cascade pump control principle implemented in this case with the use of frequency control has already firmly established itself as a standard in water supply systems, since it gives serious energy savings and an increase in the functionality of the system.

The principle of frequency regulation per pump is based on the control of the controller of the frequency converter, changing the speed of one of the pumps, constantly comparing the value of the reference with the reading of the pressure sensor. In the event of a lack of capacity of the operating pump, an additional pump will be activated on a signal from the controller, and if an alarm occurs, the reserve pump will be activated.

The signal from the pressure sensor is compared with the set pressure B of the controller. The mismatch between these signals sets the speed of the pump impeller. At the start of operation, the main pump is selected based on the estimated minimum operating time.

The main pump is the pump that this moment operates from a frequency converter. Auxiliary and standby pumps are connected directly to the mains supply or via a soft starter. In this control system, the selection of the number of working / standby pumps is provided from the controller's touch screen. The frequency converter connects to the main pump and starts running.

The variable speed pump always starts first. Upon reaching a certain speed of the pump impeller, associated with an increase in the water flow in the system, the next pump is switched on. And so on until the pressure in the system reaches the set value.

To align the resource of electric motors in time, the function of changing the sequence of connecting electric motors to the frequency converter has been implemented. It is possible to customize the switching time.

The frequency converter provides regulation and soft start only of the electric motor that is connected directly to it, the rest of the electric motors are started directly from the mains.

When using electric motors with a power of 15 kW or more, it is recommended to start up additional electric motors through soft starters to reduce starting currents, limit water hammer and increase the total pump resource.

Relay control SPL® WRP-C

The pumps are operated by a signal from a pressure switch set to a certain value. The pumps are switched on directly from the mains and run at full capacity.

The use of relay regulation in the control of pumping units provides:

1. maintaining the specified parameters of the system;

2. cascade method of control of a group of pumps;

3. mutual redundancy of electric motors;

4. alignment of the motor resource of electric motors.

In pumping units designed for two or more pumps, if there is a lack of capacity of the operating pumps, an additional pump is switched on, which will also be activated in the event of an accident of one of the operating pumps.

The pump is stopped with a preset time delay by a signal from the pressure switch on reaching the preset pressure value.

If during the next set time the relay does not register a pressure drop, then the next pump stops and then in a cascade until all pumps stop.

The control cabinet of the pumping unit receives signals from the dry-running protection relay, which is installed on the suction pipe, or from a float from storage capacity.

On their signal, in the absence of water, the control system will turn off the pumps, protecting them from destruction due to dry running.

Provides automatic activation of backup pumps in the event of failure of workers and the ability to select the number of working and standby pumps.

In pumping installations based on 3 pumps or more, it becomes possible to control it from an analog sensor 4-20 MA.

When operating pressure boosting systems with a relay principle of maintaining pressure:

1. the pumps are switched on directly, which leads to water hammer;

2. energy savings are minimal;

3. regulation is discrete.

This is almost invisible when using small pumps up to 4 kW. As the power of the pumps increases, pressure surges when switching on and off become more and more noticeable.

To reduce pressure surges, it is possible to organize the inclusion of pumps with sequential opening of the damper or install an expansion tank.

Installing soft starters allows you to completely remove the problem.

The starting current with direct connection is 6-7 times higher than the nominal, while the soft start is gentle for the electric motor and mechanism. At the same time, the starting current is 2-3 times higher than the nominal, which can significantly reduce pump wear, avoid water hammer, and also reduce the load on the network during start-up.

Direct start is the main factor leading to premature aging of insulation and overheating of the motor windings and, as a consequence, a decrease in its resource by several times. The actual service life of an electric motor largely depends not on the operating time, but on the total number of starts.

Pressure maintenance unit is a special system that is used to maintain constant heat supply at various facilities. Today, such devices can be found at a wide variety of facilities. It can be administrative buildings, residential buildings, shopping malls, and production workshops... The main task of such automatic device is to maintain a stable pressure level. Such devices are compatible with closed heating and water supply systems.

The devices can be equipped with powerful make-up units. In this case, the power of the equipment also increases. Since the membrane material is capable of working exclusively in a certain temperature range. Accordingly, the devices are best connected at those points where the temperature of the coolant does not exceed a certain indicator. If we talk about butyl tanks, it is recommended to install them on the return line. heating system... If the temperature is higher, the expansion vessel is connected using a series-connected intermediate vessel. The pressure maintenance system requires proper installation.

The installation consists of the following elements:
- expansion tank (or tank system);
- control valves;
- electronic devices.

Principle of operation.
Thanks to the unique membrane, the pressure equalization between water and air, which are located in the storage tank, is ensured. In the case of very low pressure the compressor starts to blow air. thus, if too high pressure air begins to escape through a specialized solenoid valve... This principle of work is time-tested. There is no doubt about its reliability. Leading manufacturers prefer it. This once again proves the many advantages of the principle. Many manufacturers, in order to retain air in the tank, prevent it from dissolving in water, the manufacturer separates the air and air chambers with a specialized membrane made of butylene.
Pressure maintenance unit modern model able to work smoothly even in a small area. In some systems, the unit is mounted on the side or on top of the expansion vessel, on a console. As a result, high level efficiency in the smallest space.

The modular principle is to provide special features.
As a rule, the modular principle applies to equipment with a capacity of up to 24 MW. In this case, a compressor is installed next to the main tank and the right amount additional capacities that are necessary for the full operation of the system.

Installation automation.
The pressure maintenance unit can be fully automated. In this case, the device is equipped with an automatic controlled make-up. Charging is carried out depending on the amount of water in the main tank. In this case, the simultaneous use of different vacuum units is possible. Thanks to this approach, the need for airing at the highest points of the system will disappear.

Pressure maintenance unit - advantages of use.
The advantages of using the device include the following features:
- the pressure in the system is maintained by slight fluctuations;
- if necessary, the device carries out automatic make-up;
- the system independently deaerates the water in the system;
- the absence of air even at the highest point of the system is guaranteed;
- there is no need to purchase expensive air vents and manual deaeration.

In addition to the above advantages, the silent operation of modern installations can also be noted. When operating at full capacity, the equipment functions reliably. The water in the circuit has practically no air. This feature guarantees the absence of corrosion, erosion. Moreover, the system is less polluted, worn out, and better circulation in the system is ensured. The improvement of heat transfer is provided due to the fact that there is no boiling point on the heat exchanger. Compared with membrane tanks, the pressure maintenance unit is small in size.

Low noise level during operation allows the devices to be installed in rooms with high requirements for sound insulation. The operating mode of such a system is fully automated. Thus, the plant can be integrated into any modern system that is structurally complex. On the surface that comes into contact with water, a special anti-corrosion agent is applied. Any modern pressure maintenance installation meets the existing sanitary requirements.
Power and other indicators of the system.

The pressure maintenance system can have a wide range of capacities. Naturally, with an increase in power, the volume of the tank increases. This feature is explained by the fact that the large volume of the container can compensate for the expansion. At the same time, the ratio of the total volume of the tanks to the volume of expansion of the coolant also increases.

Pressure maintenance installations (UPD, AUPD, injection and expansion machines) are complex technical systems designed to maintain pressure in heating and cooling circuits. Especially this equipment has become in demand in our country in last years due to the growth of high-rise construction caused by urbanization processes. Pumping and compressor automatic pressure maintenance systems FLAMCO replace traditional expansion vessels in heating and cooling systems in all operating pressure and temperature ranges.

The main advantage of UPDs of all manufacturers (Flamco, etc.) is the increased utilization of storage tanks (about 0.9). In the case of pumping installations, the surplus heat carrier is located in non-pressurized containers. To maintain the pressure in the system at the required level, the coolant is either added to the system by a pump (pumps), or is discharged into the storage tank through valves with electric motor drives. Compressor AUPDs are essentially modified traditional diaphragm expansion tanks, the pressure in which is controlled by the compressor and relief valves controlled by automation.

The use of AUPD Flamco instead of membrane expansion tanks allows you to quickly set the operating pressure in heating and cooling systems in wide ranges. When using conventional diaphragm tanks to change the operating pressure in the system, it is necessary to empty the tank and adjust the pressure in it. The same procedure must be carried out at each maintenance boiler room.

All Flamco pressure maintenance units are equipped with a reliable electrical power unit and a unique microprocessor controlled with LCD display. The original automatic SPCx-lw (hw) has several access levels to reliably protect the settings from unauthorized interference. A backup copy of the system settings can be saved to the SD-card by our specialist during commissioning. Automation has the ability to remotely control the operation. This function is quite simple to implement, unlike other manufacturers' ADFs.

All Flamco compressor and pumping devices are equipped with intelligent make-up control. V pumping AUPD there is a make-up going through the storage tank, in compressor rooms - directly to the heating (cooling) system.

Flamco pumping units - Flamcomat - are equipped with the function of intelligent degassing of the system, which makes it possible to reduce to a minimum the content of gases in the coolant and, accordingly, significantly reduce the corrosion load on pipelines, heating devices, heat exchangers and boilers.

Flamcomat automatic pressure maintenance (pump control)

Application area
AUPD Flamcomat is used to maintain constant pressure, compensate for thermal expansion, deaeration and compensate for coolant losses in closed systems heating or cooling.

* If the temperature of the system at the point of connection of the installation exceeds 70 ° C, it is necessary to use an intermediate tank Flexcon VSV, which provides cooling of the working fluid before installation (see chapter "Intermediate tank VSV").

Purpose of the Flamcomat installation

Maintaining pressure
AUPD Flamcomat maintains the required pressure in
system in a narrow range (± 0.1 bar) in all operating modes, and also compensates for thermal expansion
coolant in heating or cooling systems.
Flamcomat automatic control system as standard
consists of the following parts:
... membrane expansion tank;
... Control block;
... connection to the tank.
Water and air in the tank are separated by a replaceable membrane made of high quality butyl rubber, which is characterized by very low gas permeability.

Operating principle
When heated, the coolant in the system expands, which leads to an increase in pressure. The pressure sensor detects this increase and sends a calibrated signal to
Control block. The control unit, which, using a weight sensor (filling, Fig. 1), constantly records the liquid level in the tank, opens the solenoid valve on the bypass line, through which the excess coolant flows from the system to the diaphragm expansion tank (whose pressure is equal to atmospheric).
Upon reaching the set pressure in the system, the solenoid valve closes and blocks the flow of fluid from the system to the expansion vessel.

When the coolant in the system cools, its volume decreases and the pressure drops. If the pressure drops below the set level, the control unit turns on

pump. The pump runs until the pressure in the system rises to the set level.
Constant monitoring of the water level in the tank protects the pump from dry running and also prevents the tank from overfilling.
If the pressure in the system goes beyond the maximum or minimum, then, accordingly, one of the pumps or one of the solenoid valves.
If there is not enough capacity of 1 pump in the pressure line, then the 2nd pump will be activated (control unit D10, D20, D60 (D30), D80, D100, D130). AUPD Flamcomat with two pumps has a safety system: if one of the pumps or solenoids fails, the second is automatically turned on.
In order to equalize the operating time of pumps and solenoids during the operation of the unit and increase the service life of the unit as a whole, two-pump units are used
system of switching "working-standby" between pumps and solenoid valves (daily).
Error messages regarding pressure value, tank fill level, pump operation and solenoid valve are displayed on the control panel of the SDS module.

Deaeration

Deaeration in the Flamcomat automatic control system is based on the principle of pressure reduction (throttling, fig. 2). When the heat carrier under pressure enters the expansion tank of the installation (free-flow or atmospheric), the ability of the gases to dissolve in water decreases. Air is released from the water and is discharged through an air vent installed in the upper part of the tank (Fig. 3). To remove as much air as possible from the water, a special compartment with
with PALL rings: this increases the deaeration capacity by 2-3 times compared to conventional installations.

In order to remove as much excess gases from the system as possible, the increased number of cycles as well as increased time cycles (both values ​​depend on the size of the tank) are pre-programmed in the factory. After 24-40 hours, this turbo deaeration mode switches to normal deaeration mode.

If necessary, you can start or stop the turbo deaeration mode manually (if SDS-module 32 is installed).

Make-up

Automatic top-up compensates for volume losses of the heating medium due to leaks and deaeration.
The level control system automatically activates the make-up function when required, and the coolant enters the tank in accordance with the program (Fig. 4).
When the minimum coolant level in the tank is reached (usually = 6%), the solenoid on the make-up line opens.
The volume of the coolant in the tank will be increased to required level(usually = 12%). This will prevent the pump from running dry.
When using a standard flow meter, the amount of water can be limited by the make-up time in the program. When this time is exceeded, action must be taken to correct the problem. Thereafter, if the make-up time has not changed, the same volume of water can be added to the system.
In installations where impulse flow meters (optional) are used, make-up will be switched off when the program is reached.

world volume of water. If the make-up line
AUPD Flamcomat will be connected directly to the drinking water supply system, it is necessary to install a filter and protection against reverse flow(hydraulic cut-off is optional).

Basic elements of AUPD Flamcomat

AUPD Flamcomat М0 GB 300

A. Bondarenko

Application automatic installations pressure maintenance (AUPD) for heating and cooling systems has become widespread due to the active growth in the volume of high-rise construction.

AUPD perform the functions of maintaining constant pressure, compensating for temperature expansions, deaerating the system and compensating for coolant losses.

But since this is new enough for Russian market equipment, many specialists in this field have questions: what are the standard automatic control systems, what are the principles of their operation and the selection method?

Let's start by describing the default settings. Today, the most common type of automatic control system is installations with a pump-based control unit. Such a system consists of a pressureless expansion tank and a control unit, which are interconnected. The main elements of the control unit are pumps, solenoid valves, pressure sensor and flow meter, and the controller, in turn, provides control of the automatic control unit as a whole.

The principle of operation of these automatic control systems is as follows: when heated, the coolant in the system expands, which leads to an increase in pressure. The pressure sensor detects this increase and sends a calibrated signal to the control unit. The control unit (using a weight (filling) sensor constantly fixing the liquid level in the tank) opens the solenoid valve on the bypass line. And through it, the excess coolant flows from the system into the membrane expansion tank, the pressure in which is equal to atmospheric.

Upon reaching the set pressure in the system, the solenoid valve closes and blocks the flow of fluid from the system to the expansion vessel. When the coolant in the system cools, its volume decreases and the pressure drops. If the pressure drops below the set level, the control unit turns on the pump. The pump runs until the pressure in the system rises to the set value. Constant monitoring of the water level in the tank protects the pump from dry running and also prevents the tank from overfilling. If the pressure in the system goes beyond the maximum or minimum, one of the pumps or solenoid valves is activated, respectively. If the capacity of one pump in the pressure line is not enough, the second pump is activated. It is important that the automatic control system of this type has a safety system: when one of the pumps or solenoids fails, the second one should automatically turn on.

It makes sense to consider the method of selecting AUPD based on pumps using an example from practice. One of the recently implemented projects - "Residential house on Mosfilmovskaya" (object of the company "DON-Stroy"), in the central heat point which similar pumping unit... The height of the building is 208 m. Its central heating station consists of three functional parts, which are responsible, respectively, for heating, ventilation and hot water supply. The heating system of the high-rise building is divided into three zones. Total estimated thermal power heating systems - 4.25 Gcal / h.

We present an example of the selection of AUPD for the 3rd heating zone.

Initial data required for the calculation:

1) thermal power of the system (zones) N system, kW. In our case (for the 3rd heating zone), this parameter is 1740 kW (initial project data);

2) static height H st (m) or static pressure R st (bar) is the height of the liquid column between the connection point of the unit and highest point system (1 m liquid column = 0.1 bar). In our case, this parameter is 208 m;

3) the volume of the coolant (water) in the system V, l. For the correct selection of AUPD, it is necessary to have data on the volume of the system. If exact value unknown, the average value of the water volume can be calculated by the coefficients given in the table... According to the project, the water volume of the 3rd heating zone V sist is equal to 24 350 liters.

4) temperature graph: 90/70 ° C.

First step. Calculation of the volume of the expansion tank to the AUPD:

1. Calculation of the expansion coefficient TO expansion (%), which expresses the increase in the volume of the coolant when it is heated from the initial to the average temperature, where T Wed = (90 + 70) / 2 = 80 ° C. At this temperature, the expansion coefficient will be 2.89%.

2. Calculation of the volume of expansion V rassh (l), i.e. the volume of the coolant displaced from the system when it is heated to an average temperature:

V ext = V sist. K ext / 100 = 24350. 2.89 / 100 = 704 liters.

3. Calculation of the estimated volume of the expansion tank V b:

V b = V ext. TO zap = 704. 1.3 = 915 liters.
where TO zap - safety factor.

Next, we select the standard size of the expansion tank from the condition that its volume should not be less than the calculated one. If necessary (for example, when there are size restrictions), the AUPD can be supplemented with an additional tank, dividing the total estimated volume in half.

In our case, the volume of the tank will be 1000 liters.

Second phase... Selection of the control unit:

1. Determination of the nominal working pressure:

R sist = H sist / 10 + 0.5 = 208/10 + 0.5 = 21.3 bar.

2. Depending on the values R sist and N system, we select the control unit according to special tables or diagrams provided by suppliers or manufacturers. All models of control units can include either one pump or two. In AUPD with two pumps in the installation program, you can optionally select the operating mode of the pumps: "Main / standby", "Alternate operation of pumps", "Parallel operation of pumps".

This completes the calculation of the AUPD, and the volume of the tank and the marking of the control unit are prescribed in the project.

In our case, the automatic control unit for the 3rd heating zone must include a free-flow tank with a volume of 1000 liters and a control unit that will ensure that the pressure in the system is maintained at least 21.3 bar.

For example, for this project was chosen AUPD MPR-S / 2.7 for two pumps, PN 25 bar and MP-G 1000 tank from Flamco (Netherlands).

In conclusion, it is worth mentioning that there are also compressor-based installations. But that's a completely different story ...

Article provided by ADL Company