Equipment for network installations and hot water supply. We select a network feed pump for a boiler room

K category: Boiler installation

Equipment for network installations and hot water supply

Network and recirculation pumps. For filing hot water to the consumer, in boiler rooms use network pumps that ensure the continuous movement of water in heating networks.

Network pumps are installed on the return line of heating networks, where the temperature network water does not exceed 70 °C. In steam boiler houses, network pumps supply water returned from the consumer to the heater system, after which it is sent with a temperature of 150 ° C to the direct network water line - to the consumer. In water-heating boiler houses, the return network water is pumped by network pumps through the boilers and, heated to the same temperature, is supplied to the consumer. The choice of appropriate pumps and their mode of operation depend on the hydraulic resistance of the boiler-consumer system.

In boiler houses of small and medium power, pumps of the type K, D, TsN are used as network pumps.

Centrifugal cantilever single-stage pump type K, single-sided suction with a horizontal axial fluid supply to the impeller (Fig. 57) consists of a spiral casing, to which a suction pipe U is attached, which simultaneously serves as a cover. The impeller is attached to the shaft 5 with a nut with a left-hand thread to prevent self-unscrewing. All body parts and the impeller are cast iron.

During the rotation of the impeller, made of two discs connected by blades, water is thrown to the walls of the casing outward through the discharge pipe under the action of centrifugal force. An inlet hole is made in the front disk, and there are unloading holes in the rear disk to equalize the axial force. The impeller has sealing bands, which, together with protective rings pressed into the housing and suction pipe Y, form a seal to reduce the flow of fluid from the high pressure area to the area low pressure. The volute housing serves to convert kinetic energy fluid after the impeller into pressure energy.

The stuffing box seal of the shaft is made in the form of individual rings made of impregnated cotton cord, which are installed with a relative offset of the cut by 120°. The sleeve protects the shaft, mounted on two bearings in the support bracket, from wear.

The pumping unit (Fig. 58) includes a pump U, assembled with an electric motor on a foundation plate. The rotation of the pump rotor is transmitted from the electric motor through a coupling protected by a shield.

The centrifugal horizontal single-stage double-suction pumping unit consists of a D-type pump and an electric motor connected to it by a coupling, which are installed on a foundation plate. In the lower part of the pump housing, the suction and discharge pipes are horizontally located, directed in opposite directions at an angle of 90° to the pump axis. Such an arrangement of nozzles and a horizontal split of the casing make it possible to disassemble the pump, inspect and replace the working parts without removing the pump from the foundation and without dismantling the engine and pipelines.

Rice. 1. Longitudinal section of a centrifugal pump type K: 1.3 - branch pipes, 2 - housing, 4 - impeller, 5 - shaft, 6 - gland seal, 7 - bushing, 8 - stuffing box cover, 9 - bracket, 10 - bearings, 11 - rings

The pumping units are supplied by the manufacturer complete with an electric motor on a foundation plate.

Rice. 2. Pump unit with centrifugal pump type K: 1 - pump, 2 - coupling, 3 - electric motor, 4 - foundation plate

Rice. 3. Horizontal single stage centrifugal pump type D unit: 1 - housing, 2 - bearing supports, 3 - sealing units, 4 - impeller, 5 - coupling, 6 - electric motor, 7 - foundation plate, 8, 11 - nozzles, 9 - cover, 10 - shaft

Centrifugal pumps of type TsN, used as network pumps, have a design similar to pumps of type D.

In hot water boilers, in order to reduce the intensity of external corrosion of pipes of steel hot water boilers, it is necessary to maintain the temperature of the water at the inlet to the boilers above the dew point temperature flue gases. To do this, recirculation pumps are installed in boiler rooms that increase the temperature of the water at the inlet to the boiler by mixing hot water from the direct network water line behind the boiler. Valves control the temperature of the water entering and exiting the boiler.

As recirculation pumps centrifugal pumps of the NKU type are used, which have an axial fluid supply similar to type K pumps and are supplied complete with an electric motor on a common frame.

In cases where the pressure generated by a pump with one impeller is insufficient, multistage pumps are used. In these pumps working fluid passes sequentially through two or more wheels, while the pressure generated is equal to the sum pressure developed by each wheel.

Single-stage centrifugal pumps are used to pump water through water treatment filters, heat supply systems and in other cases when it is not required high pressure working environment. Multistage pumps are used to supply feed water into the boiler.

Rice. 4. Scheme of installation of recirculation pumps: 1, 5 - return and direct network water, respectively, 2-network pump, 3 - hot water boiler, 4 - recirculation pump, 6 - control valves

In the marking of pumps, the numbers following letter designation pump type, mean flow (capacity, m3 / h) and pressure (m water column). For example, the performance of the D200-95 pump is 200 m3 / h, and the pressure is 95 m of water. Art.

Gryazeviki. In boiler rooms, mud collectors are installed in front of the network pumps (on the suction line), the principle of operation of which is based on a sharp decrease in the speed of water movement, as a result of which suspended particles settle to the bottom.

The mud trap consists of a body made of steel pipe, inlet and outlet pipes. The latter is equipped with a removable filter. Sludge is removed with taps.

Heaters. Apparatuses in which the process of transferring heat from a medium with more high temperature to an environment with a lower temperature are called heat exchangers or heaters.

In boiler rooms, as a rule, surface-type heaters are used. The heat exchange surface is formed by pipes located inside the heat exchanger housing. Through the walls of the rough, heat is transferred from the heating medium to the heated medium.

Depending on the heating medium, heat exchangers are steam-water (heating medium - steam) and water-water (heating medium - water).

The steam-water heater is a horizontal apparatus of rigid construction with elliptical or flat bottoms. In the upper part of the body there is an annular pipe for installing a pressure gauge and an air valve. The pipe system 6 is made of brass pipes with a diameter of 16X1 mm, which are expanded in tube plates welded to the body.

Steam supplied through the upper fitting into the annular space, condensing, heats the water circulating in the tubes. The condensate is discharged through the lower branch pipe. The heated water enters and exits through fittings in the heat exchanger chamber.

The marking of a steam-water heater, for example PP2-24-7-1U, means: PP - steam-water heater; 2 - heater version with flat bottoms (1 - with elliptical bottoms); 24 - rounded heating surface area, m2; 7 - operating pressure of heating steam, 0.1 MPa; IV - the number of moves on the water.

Water-water sectional heater consists of a body made of seamless steel pipe and enclosed in it a pipe system of brass pipes with a diameter of 16X1 mm, a length of 2000 or 4000 mm, which are flared in blind flanges 5. Adjacent sections are connected by bent rolls 6 on the flanges. The marking of a water-to-water heater, for example 4-76X2000-R-2, means: 4 - heater number; 76- outside diameter body, mm; 2000 - pipe length, mm; P - detachable version of the heater; 2 - number of sections.

Rice. 5. Mud tank: 1 - housing, 2, 4 - nozzles, 3 - air cock, 5 - filter, 6 - cock

Rice. 6. Two-way steam-water heater: 1.9 - chambers. 2 - valve, 3 - steam inlet, 4 - manometer pipe, 5 - housing, 6 - pipe system, 7 - pipeline to the deaerator, 8 - cover, 10 - condensate outlet, 11 - support

Rice. 7. Water-water two-section heater: 1.2 - inlet and outlet of heated water, 3.8 - inlet and outlet of heating water, 4 - pipes, 5 - flanges, 6 - coil, 7 - housing

Water-water sectional heaters with blocks of supporting partitions are currently widespread (Fig. 64). Each partition is made of brass in the form of a part of a circle with holes for tubes, and adjacent partitions, the distance between which is 350 mm, are shifted relative to one another by an angle of 60° and connected along the periphery by rods. The supporting partitions are interconnected into a block and attached to the heater body with rings.

Rice. 8. Block of supporting partitions of the water-water heater section: 1 - partition, 2 - rod, 3 - ring

Rice. 9. Block of network pumps: 1.2 - pipelines, 3 - pump, 4 - sump, 5 - metal structure

When using blocks of supporting partitions with knurled brass tubes, the thermal power and significantly increases the service life of the heater.

Blocks network settings hot water supply. In the boiler room, network water heaters and network pumps, which make up the network installation equipment complex, are assembled into currents.

Rice. 10. Block of network water heaters BPSV-14: 1.2 - heaters, 3 - metal structure

The network pump units include a sump, a common supporting metal structure, suction and pressure pipelines equipped with sliding and fixed supports, pipeline accessories, electrical appliances, as well as control and automation devices.

BPSV-14 network water heater unit with a capacity of 14 Gcal/h, designed to heat network water to a temperature of 150 °C, includes a system of steam and water heaters, a supporting metal structure, stairs and maintenance platforms, piping with fittings, instrumentation and instrumentation .

The large-block hot water supply unit KBUGV is used to prepare water at a temperature of 70 ° C in a centralized hot water supply system. The unit consists of two transportable units (upper and lower), including pumps, a working water tank, hot water heaters, pipelines, fittings, as well as control and automation devices.

All equipment of the installation is located inside the three-dimensional metal structures. The lower block is equipped with a monorail with manual hoist for excavation of electric motors for the purpose of repair or replacement.

Before sending to the object, they carry out hydraulic tests blocks of network installations and hot water supply installations and apply thermal insulation on them.

Currently, boiler houses use a unified series of aggregated blocks of equipment for the technological part and water treatment plants.

Circulating network pumps for installation in a boiler room or heating have been used by many owners of private households and summer cottages for a long time. Steam piston pumps allow you to provide the premises with heat at any time of the year, since they do not depend on utility networks.

In this article, we will tell you what the operation of such devices for thermal boilers is, what are the features of use, and how to correctly calculate the power of pressure, heat and pipeline resistance when buying equipment.

1 How to choose a device?

The feed pump for water circulation and thermal boilers is selected based on the following nuances:

• the amount of heat required to heat the building;
• calculation of the thermal insulation index of walls;
• climatic conditions of the region where the consumer lives;
• is there in the building window frames and how many of them;
• selection is also carried out taking into account the structure of the surface of the ceiling and floor.

To correctly calculate the device for circulating water, the choice of the unit for thermal boilers is carried out with the choice of heat carrier. The selection of this element includes an analysis of the properties of viscosity, heat transfer, and heat capacity. In order for the operation of thermal boilers to be the most efficient and balanced, network pumps are selected taking into account these parameters.

1.1 Features of use

The calculation and selection of a device for water circulation should be carried out taking into account all aspects. For example, if you buy a SE 2500 60 pump, and the power of your system is less, then the circulation unit will consume an order of magnitude more electricity. In addition, the SE 2500 60 pump, when operating in a low-power system, will provoke the appearance of noise in the pipes, which indicates that the feed pump was selected incorrectly.

However, the noise in the pipes is not always the result of incorrect operation of the water circulation device for the boiler room. Often, noise occurs when an air lock has formed in the batteries. The process of removing air pockets is carried out using specialized valves, but this must be done before you start heating the house.

In the event that there is no air in the pipes, and the system as a whole is running, the feed pump should work for some time, after which the process of removing the air plug is repeated again. Then the pump SE 800 or another brand should be adjusted again, however most of companies produce circulation devices with the function automatic adjustment. When the air lock is completely removed and the device is adjusted, the boiler room will be ready for full operation.

If your circulation steam pump is unregulated, then the first start of water should be made at the smallest pressure. Regulated SE pumps for thermal boilers only need to be configured in such a way that the unlocking function is enabled - then the device will independently regulate the pressure. Modern units for water circulation are equipped with a metal case and ceramic bearings. Thanks to this, the operation of the unit will be almost silent.

1.2 Power calculation

The calculation and selection of the power that SE pumps have is made from an analysis of the need for heat in a house or room. The calculation of this indicator is carried out taking into account the coldest temperatures climate zone where the consumer lives.

Below we will tell you how to correctly determine required indicators so that the pressure during operation of the device is the most optimal and can warm the whole house.

1.3 Heat

Heat calculation is the first thing to do when choosing PE feed pumps. First of all, in order for the operation of thermal boilers to be more efficient, it is necessary to calculate the area of ​​\u200b\u200bthe building that it will heat. In accordance with international standards, the calculation is made as follows:

• For one square meter a house in which two apartments are located, you will need a FE 800 100 W energy device or from another manufacturer.
• For multi-storey buildings you can purchase a circulation pump SE 1250 70, an apparatus SE 500 70 or any other circulation pump in which the power is 70 watts.

If the house was built in violation of the norms, then when calculating the power part of the building should be used increased level heat consumption. In the event that your house or building is equipped with additional thermal insulation, then for thermal boilers of these systems, you can use drives with a consumption of 30 to 50 W / m². In the countries of the post-Soviet space, utilities are engaged in the calculation according to the following principle:

• Small buildings (1-2 floors) consume about 170 W / m² if the air temperature is 25 degrees below zero. If the temperature drops to -30, then this figure increases to 177 W / m².
• If the building is multi-storey, then the heat boiler drives will consume about 97-102 W / m².

Now, as for the choice of performance, which the drives should have.

It can be pump SE 1250 70, apparatus SE 500 70 or any other, performance calculation is carried out according to the formula G=Q/(1.16xDT), where:

• 16 is an indicator of the specific heat capacity of the liquid.
• DT is the difference temperature conditions in the supply and return pipelines. Usually this figure is about 20 degrees. AT low temperature systems it is reduced to 10%, and if the building is equipped with a system of underfloor heating, then only 5 degrees.

2 Pressure calculation

In addition to the above parameter, the SE 1250 140 pump or any other drive must create required pressure, that is, pressure. The pressure indicator must be such that the liquid can circulate through the system without problems. When designing a new building, it will be difficult to calculate the head pressure so that the result is accurate. As a rule, all information is indicated in the service book for the SE 500 pump or another brand. How to calculate the head using the formula H=(RxL+Z)/p*g:

• R is the resistance index in a flat pipe;
• L is the total length of the pipeline;
• Z is the reinforcement resistance index;
• p is the density;
• g is the free fall acceleration index.

Please note given formula pressure calculation is relevant only for new heating systems.

2.1 Pipeline resistance

If you decide to purchase a SE 1250 140 pump or a SE 800 100 device, or from another manufacturer, then you should not forget about the resistance of the pipeline. In practice, experts have found that this indicator varies in the region of 100-150 Pa/m.

Then the pressure that the pump SE 1250 140 or any other should have should be from 0.01 to 0.015 m per meter of pipe.

Also, experts assure that when water passes through reinforced sections, about 30% of the entire pressure force is lost. If the system is additionally equipped with a thermostatic expansion valve, then this figure can be increased by 70%.

When you have calculated all the necessary parameters, you need to decide on the budget and select a device that matches the characteristics obtained. If there is no such unit, then the characteristics should be at least approximately the same. Remember that the numbers obtained are indicators of the operation of the device at maximum loads.

But since the need to use devices with heavy loads is minimal and can only occur a few times a year, if you need to choose a more powerful or less powerful unit, experts recommend opting for a less powerful one. In practice, this does not affect the operation in any way. heating system generally.

2.2 Network pump Etaline - dismantling, installation, troubleshooting (video)

If the boiler room is designed correctly, then it will serve both heating systems, and ventilation, and the supply of hot and cold water. Independently, it can be said, no one designs communications. Focus on at least a typical plan. Its choice depends on the type of room to which it is intended.

The graphic drawing should reflect all mechanisms, devices, devices, as well as pipes connecting them. AT standard schemes the boiler room includes both boilers and pumps (circulation, make-up, recirculation, network), and accumulators, and condensation tanks. It also provides for fuel supply devices, its combustion, as well as devices for deaeration of water, heat exchangers, the same fans, heat shields, control panels.

The type of coolant, as well as thermal communications and, importantly, water quality, affect what the equipment will be like and where to place it.

Those heating network that work on water are divided into two groups:

• Open (liquid is taken in local settings);
• Closed (water returns to the boiler, giving off heat).

The most popular example of a circuit diagram is an example of a hot water boiler open type. The principle is that the circulation pump is installed on the return line, it is responsible for delivering water to the boiler, and then throughout the system. The supply and return lines will be connected by two types of jumpers - bypass and recirculation.

The technological scheme can be taken from any reliable sources, but it would be good to discuss it with specialists. He will advise you, tell you if it is suitable for your situation, explain the whole system of action. In any case, this essential construction for a private house, therefore, attention should be maximum.

How to use the thermal scheme of the boiler room

The thermal diagram helps to monitor the status and functioning. Due to flue gases, the appearance of corrosion of metal coatings of low-temperature or sulfuric acid is not excluded. And so that it does not appear, you should control the temperature of the water. It is noteworthy that at the entrance to the boiler optimal temperature will be 60-70 degrees.

And in order to be able to raise the temperature to the desired values, a recirculation pump is installed. Hot water boilers need to be monitored so that their service life is decent, control the constancy of water consumption. Typically, the minimum data for this indicator is set by the manufacturer.

For boilers to work well, vacuum deaerators must be used. Typically, a water jet ejector will create a vacuum, and the released steam is used for deaeration. But, the main thing that they are afraid of when installing a boiler room is a constant binding to a place. Modern automation simplifies many processes.

Automation and scheme of the boiler plant

Automation makes it possible to use a set of programs that control heat flows. It also depends on the mode of the day, on the weather. Including, it is necessary for heating additional premises: game room, swimming pool.

There are some popular custom features that adapt the operation of the equipment with an eye on the lifestyle of the owners of the house. This and conventional system supplies hot water, and a complex of some individual options that are convenient for these residents, economical. In the same way, you can develop a boiler room automation scheme by selecting one of the popular modes.

Selection of a make-up pump for a boiler room

The charge pump must develop a high pressure greater than in the heating circuit with a relatively small supply. Still, for replenishment, pumping of large volumes of liquid is not necessary. The selection of such a pump is carried out according to several requirements.

Feed pump selection:

• It must create a pressure that will exceed the pressure in the CO return;
• Also, the pressure must be able to push through the hydraulic resistance of the pressure sensor, pipeline;
• More important criterion is the flow rate, in particular, for closed CO, the leakage rates are equal to half a percent of the volume of the coolant in the boiler and heating circuit.

At the same time, I would like to say that it is not very practical to purchase such a pump for work. In the sense that it should not serve only for recharge. He can also perform additional functions, for example, be a backup circulation pump, and also be used to pump and drain water into the circuit.

What is the scheme of the boiler room (video)

If you are planning to build a boiler house, it will not be superfluous, of course, to look into the textbook, remember what a thermal mechanical system is, etc. But you can see the suggested ready scheme, discuss them with experts, and choose the right one, taking into account all modern possibilities.

Pumps are machines designed to move liquids and give them energy. Feed, make-up, network, condensate, circulation and other pumps are installed in boiler rooms. They are selected for performance and pressure. The number of pumps must be at least two, one of which is standby. In boiler rooms, bladed (centrifugal, vortex, axial) and jet (ejectors, injectors) pumps are used. The pump is driven by electric motors, which are usually connected by means of a coupling.

1. Feed pumps. In boiler rooms with steam boilers feed pumps are installed, which can be centrifugal and piston (with electric or steam drive). Their number should be at least two with independent drives, and one pump (or more) should be with a steam drive.

Productivity of one pump with electric drive, kg/s

Pressure generated by the feed pump, MPa

The selection of the pump is made according to the table. 15.3. We choose 2 productive pumps.

The performance of the feed pump (standby) with a steam drive must be at least 50% of the nominal capacity of all boilers

The pressure remains the same = 1.672 MPa.

The selection of reciprocating steam pumps is made according to Table. 15.7.

2. Network pumps. Designed to create circulation and are installed on the return line of heating networks, where the water temperature does not exceed 70 °C. The performance of the network pump is determined by the total consumption of network water \u003d 16.62 kg / s or 59.8 m 3 / h.

1.1*=59,8*1.1=65,8

The pressure of the network pump is accepted MPa

The selection of network pumps is made according to the table. 15.4…15.6 .

3. Condensate pumps

Their performance is determined based on the maximum amount of condensate, and the pressure must be sufficient to overcome the resistance of the condensate pipelines, the pressure in the deaerator and the hydrostatic head due to the difference in the levels of the installation sites of the pump and the deaerator (approximately MPa). The selection of the condensate pump is made according to the table. 15.10.

4. Make-up pumps. Serve to replenish water leakage from the heating system. We select the performance of the make-up pump twice as large for the possibility of emergency make-up of the heating network

The required pressure of the make-up pump is determined by the water pressure in the return line of the heating system and the resistance of pipelines and fittings on the make-up line, approximately

The selection of the make-up pump is made according to the table. 15.10.

5. Raw water pump. Designed to supply water from the source of water supply to the boiler house (reservoir, water pipe, well) to the water treatment system (HVO). as pumps raw water We use a K.

The pump performance is

The required head of the source water pump is selected MPa

The selection of the network pump is made according to the table. 15.10.

The results of the selection of all pumps are summarized in the final table.

Table 10. Summary table for pump selection

According to their purpose, pumps are divided into circulation (network), make-up, recirculation (mixing) and feed.

Circulation pumps are designed to move the coolant along closed loop from the heat source to the heaters. Supply of pumps D m 3 / s. determined by the formula

D=Q calc /C∆t calc

Q calc - maximum heat output of the boiler, kW (kcal/h); C - heat capacity of water, kJ / m 2 -deg (kcal / m 3 xdeg); ∆tcalc = t calc (trans)-t calc (rev) - accepted calculated temperature difference between hot and return water, °С

The necessary calculation set Ncalc, m, created by network pumps, is determined by the formula

N calc \u003d N to + N ng + N ns

where N to - pressure loss to overcome the resistance of the network in the boiler room, m; N ng - pressure loss to overcome resistance in external heating networks, m; N ns - pressure loss to overcome resistance in the local heating system.

In hot water boilers closed systems ah heat supply usually install two circulation pumps: one working, the other - reserve. To make up for leaks in the heat supply system, two make-up pumps are used: one is working, the other is standby (Fig. 45). The supply of the make-up pump is usually equal to 1 - 2% of the hourly consumption of network water. The pressure created by the make-up pump, depending on the temperature of the water in the system, is in the range of 30-60 m. The make-up pumps are connected to the suction line of the network pumps.

Figure 45. Scheme of installation of pumps and their piping in a hot water boiler. 1 - circulation and network pumps; 2- hot water boilers; 3 - mixing or recirculating pumps; 4 - make-up pumps; 5 - jumper for cooling water entering the heating network

To avoid dew on convective surfaces hot water boilers in heating boiler rooms, recirculation (mixing) pumps are installed. The performance of recirculation pumps for closed heat supply systems is determined at ambient temperature tn = 0 ° C, and the calculated pressure is determined depending on the hydraulic resistance of the recirculation ring.

In low-pressure steam boilers (Р≤0.07 MPa; 0.7 kgf / cm 2), feed pumps are installed to feed the boilers (Fig. 46), as a rule, two centrifugal pumps: one is working, the other is reserve, which must work under the bay. The flow of each pump must be at least 100% of the maximum flow of the entire boiler room. The design head of the feed pump Hnas, kPa (m), is determined by the empirical formula

N us \u003d 1.15P + N set or N us \u003d 1.15x10P + N set

where P is the working pressure in the boilers, kPa (ati); H set - resistance of the suction to discharge pipelines, including the static head between the pump axis and the place where water enters the boiler (usually H set -98-196 kPa; 10-20 m).

With a boiler room steam capacity of less than 0.14 kg / s, one centrifugal and one backup manual feed pumps are installed, and for boilers with a steam capacity of up to 4.2x10 -2 kg / s of steam, only one manual pump is installed.

Bulk power of a centrifugal pump N, W, is determined by the formula

N=D n N n /ȵ a

where D n - estimated flow of the pump, m 3 / s; Hn - design head, Pa; ȵ a - pump efficiency

Figure 46. Scheme of installation of pumps and their piping in a low-pressure steam boiler room Р≤ 0.07 MPa (0.7 kgf / cm 2). 1 - condensation tank; 2 - floating wooden lids, to reduce the absorption of oxygen from the air; 3 - intermediate partition; 4-feed pump; 5 - hand pump

Centrifugal pumps pump water under the action of the centrifugal force developed during their rotation. The speed of rotation of the impeller is 1500-3000 min -1 . Before operation, the centrifugal pump must be filled with water, for which a funnel with a valve is installed on the discharge line.