Any building connected to a centralized heating network (or boiler room) has an elevator unit. The main function of this device is to lower the temperature of the coolant while simultaneously increasing the volume of pumped water in the house system.
Node purpose
Elevator units are installed when superheated water, the temperature of which can exceed 140 ºC, is supplied to a residential building from a thermal power plant or boiler house. It is unacceptable to supply boiling water to apartments, as this can lead to burns and destruction of cast iron radiators. These devices cannot withstand sudden temperature changes. As it turns out, polypropylene pipes, which are so popular today, also do not like high temperatures. And although they do not collapse from pressure hot water in the system, their service life is significantly reduced.
Superheated water supplied from the combined heat and power plant first enters the elevator unit, where it is mixed with cooled water from the return pipeline of the residential building and again supplied to the apartments.
Operating principle and unit diagram
The hot water entering a residential building has a temperature corresponding to the temperature schedule of the combined heat and power plant. Having overcome the valves and dirt filters, the superheated water enters the steel body, and then through the nozzle into the chamber where mixing occurs. The pressure difference pushes a stream of water into the expanded part of the housing, and it connects with the cooled coolant from the heating system of the building.
The superheated coolant, having a reduced pressure, rushes at high speed through the nozzle into the mixing chamber, creating a vacuum. As a result, in the chamber behind the jet, the effect of injection (suction) of coolant from the return pipeline occurs. The result of mixing is water at the design temperature, which enters the apartments.
The elevator device diagram gives a detailed idea of the functionality of this device.
Advantages of water jet elevators
A special feature of the elevator is the simultaneous performance of two tasks: to work as a mixer and as a circulation pump. It is noteworthy that the elevator unit operates without the cost of electricity, since the operating principle of the installation is based on the use of differential pressure at the inlet.
The use of water jets has its advantages:
- simple design;
- low cost;
- reliability;
- no need for electricity.
Using the latest models of elevators equipped with automation, you can significantly save heat. This is achieved by regulating the temperature of the coolant in its outlet area. To achieve this goal, you can lower the temperature in apartments at night or during the day, when most people are at work, study, etc.
The economical elevator unit differs from the conventional version by the presence of an adjustable nozzle. These parts can have different designs and levels of adjustment. The mixing coefficient of a device with an adjustable nozzle varies from 2 to 6. As practice has shown, this is quite sufficient for the heating system of a residential building.
The cost of equipment with automatic adjustment is significantly higher than the price of conventional elevators. But they are more economical, functional and effective.
Possible problems and malfunctions
Despite the durability of the devices, sometimes the elevator heating unit malfunctions. Hot water and high pressure quickly find weak points and cause breakdowns.
This inevitably happens when individual components are assembled of poor quality, the calculation of the nozzle diameter is incorrect, or due to the formation of blockages.
Noise
The heating elevator can create noise when operating. If this is observed, it means that cracks or scuffs have formed in the outlet part of the nozzle during operation.
The reason for the appearance of irregularities lies in the distortions of the nozzle caused by the supply of coolant under high pressure. This happens if the excess pressure is not throttled by the flow regulator.
Temperature mismatch
The quality operation of the elevator can also be questioned when the inlet and outlet temperatures differ too much from the temperature curve. Most likely, the reason for this is the oversized nozzle diameter.
Incorrect water flow
A faulty throttle will result in a change in water flow compared to the design value.
Such a violation can be easily determined by changes in temperature in the incoming and return piping systems. The problem is solved by repairing the flow regulator (throttle).
Faulty structural elements
If the connection diagram of the heating system to the external heating main has an independent form, then the cause of poor-quality operation of the elevator unit can be caused by faulty pumps, water heating units, shut-off and safety valves, all kinds of leaks in pipelines and equipment, and malfunction of regulators.
The main reasons that negatively affect the design and principle of operation of pumps include the destruction of elastic couplings in the connections of the pump and electric motor shafts, wear of ball bearings and destruction of seats for them, the formation of fistulas and cracks in the housing, aging of oil seals. Most of the listed faults can be eliminated by repair.
The problem of fistulas and cracks on the body is solved by replacing it.
Unsatisfactory operation of water heaters occurs when the tightness of the pipes is broken, they are destroyed or the tube bundle sticks together. The solution to the problem is to replace the pipes.
Blockages
Blockages are one of the common causes of poor heat supply. Their formation is associated with dirt entering the system when dirt filters are faulty. Deposits of corrosion products inside pipes also increase the problem.
The level of filter clogging can be determined by the readings of pressure gauges installed before and after the filter. A significant pressure drop will confirm or refute the assumption about the degree of clogging. To clean the filters, it is enough to remove dirt through the drainage devices located in the lower part of the housing.
Any problems with pipelines and heating equipment must be eliminated immediately.
Minor comments that do not affect the operation of the heating system are necessarily recorded in special documentation and are included in the plan for current or major repairs. Repairs and corrections take place in the summer before the start of the next heating season.
The elevator unit is an element of the heating system that allows you to reduce the temperature of the coolant supplied from the thermal power plant to the optimal level. The heating elevator mixes high-temperature coolant from the thermal power plant and cooled coolant from the return line of the heating system apartment building. By regulating the volume of coolant in two flows, it is achieved optimal temperature for the home heating system.
The temperature of the coolant in the external heating pipelines reaches +130°C - +150°C (if the water supply comes from large thermal power plants), or +95°C - +105°C (from small thermal power plants, local boiler houses).
Using water at this temperature is impossible for several reasons:
- The water temperature in the heating mains coming from the thermal power plant is high. But with poor thermal insulation of the system and a sharp drop in air temperature, sudden changes are possible.
- Such differences negatively affect the service life of the internal heating system of residential buildings. For example, cast iron radiators, which are often used in the internal circuit of heating systems, can crack due to sudden temperature changes;
- Recently, they have been widely used in heating systems of residential buildings. Plastic pipes at temperatures above +95°C they become deformed and also leak or crack. (Propylene can withstand temperatures of +100°C, but provided that this temperature does not last long);
- Touching pipes heated above +90°C can cause burns.
Note! According to SNiPs, the temperature of the coolant in buildings where people are located should be no more than +95°C on the supply side and no more than +70°C on the return side.
Therefore, for heating residential buildings, a dependent connection scheme is rarely used, according to which the coolant from the heating network enters directly into house system heating. In most cases this is simply not possible.
More often we are dealing with a dual-circuit system, the so-called independent connection scheme.
In this case, water from the thermal power plant or boiler room enters the heat exchanger, in which, by mixing the external and internal circuit water, the latter is heated to a temperature acceptable for use.
It is here that the elevator heating unit is used as a device for mixing hot and cold flow to an acceptable temperature necessary and sufficient for operation in the internal system.
The elevator unit, despite the simplicity of its design, performs 2 functions - under the influence of pressure differences it works as a pump and a water mixer. Therefore, in some sources this device is called a water-jet heating elevator or mixing pump.
Elevator unit design
The elevator consists of 4 elements:
- A cone-shaped nozzle through which a hot flow of coolant coming from the heating main passes at high speed;
- Suction chamber, into which cooled coolant flows from the return line;
- Mixing cone and neck, where the mixing of hot and cooled coolant occurs;
- Diffuser.
Note! The coolant contains various mechanical particles (sludge, scale, etc.), which gradually grind down the elevator nozzle. Therefore, every year the elevator is disassembled to check the nozzle diameter. If the nozzle diameter does not correspond to the documents, it must be replaced.
Most often, when describing a heating system with an elevator unit, it is assumed that it is impossible to regulate the output temperature to the internal circuit.
However, recently improved models have become popular. A cone-shaped rod is placed inside the nozzle, which, depending on its position, can change the throughput of the nozzle. The position of the rod can be changed manually or automatically. When installing an automatic control unit, the device must be connected to a power source.
Installation of an elevator unit requires accurate calculations. It is better if this part of the work is done by a professional. However, at the same time, you can check the correctness of the chosen model yourself by calculating the required dimensions of the device.
And for the average user who is not familiar with the formulas for calculating the mixing coefficient and nozzle diameter, there are simple programs that will help perform the calculations.
For calculations you will need:
- temperature at the inlet and outlet of the external circuit (water temperature in the heating main) and the temperature of the internal network (house heating system);
- coolant consumption;
- heating system resistance.
Advantages of a system with an elevator unit
- Low cost.
- Energy independence. The elevator heating unit operates in the presence of the required pressure difference on the internal and external circuits;
- Simplicity of design and installation (with making the right choice devices, accurate calculations of the nozzle diameter).
- Independence of the unit’s operation from short-term pressure drops and temperatures of the external heating main.
Flaws
- The outlet temperature is not always adjustable. For example, at a low temperature of the coolant in the heating main, after mixing with cooled water (return), water will initially flow into the internal circuit pipes, the temperature of which is not sufficient to heat the room. This problem is currently being solved by installing adjustable units. Adjustment can be made manually(rotation of the valve) or automatic (adjustment occurs due to the movement of the rod installed inside the nozzle, movement occurs due to the connection of a servo drive connected to sensors);
- For stable operation of a system with an elevator unit, precise selection of design is necessary;
- Some users consider one of the disadvantages to be the material investments required to purchase additional equipment and installation of elevator heating units. But with proper installation of high-quality equipment, even a system with automatic control bandwidth nozzles pay for themselves within 3-5 years (due to savings on heating fees).
Scheme of a scheduled check of the operating condition of the elevator unit
One of the advantages of the system is ease of operation. The device does not require round-the-clock monitoring; routine inspections are sufficient. This kind of examination is best performed according to the following algorithm:
- Checking the integrity of pipes;
- Verification of instruments, adjustment of pressure sensors and thermometers;
- Calculation of pressure loss when water passes through the nozzle;
- Calculation of the displacement coefficient. This value must be taken into account when setting up the system, since even a perfectly installed and installed node and the pipeline wear out over time.
After a routine inspection, the system is sealed to secure its settings and prevent unauthorized changes.
Installation of an elevator unit
As a rule, the installation of an elevator heating unit is carried out in the basement. The use of such a place is possible subject to a number of requirements:
- This must be an indoor room with a positive temperature (above 0°)
- Due to the large temperature difference, droplets of water settle on pipes in a humid room (condensation forms). This leads to rapid wear of the equipment. To keep the pipes dry, it is necessary to install an exhaust ventilation system.
Advice! You can also get rid of condensation by insulating pipes. A layer is applied to the pipeline liquid thermal insulation, or “put on” heat-insulating tubes made of foamed polyethylene.
In systems with an automatic heating elevator, installation of an independent power source is provided for uninterrupted power supply. Autonomous power supply will ensure the operation of devices even during a power outage.
Video
The heating system is one of the most important life support systems at home. Every home uses a certain heating system, but not every user knows what an elevator heating unit is and how it works, its purpose and the opportunities that are provided with its use.
Heating elevator with electric drive
Operating principle
The best example that will show the operating principle of a heating elevator would be a multi-storey building. It is in the basement of a multi-story building that you can find an elevator among all the elements.
First of all, let's look at the drawing of the elevator heating unit in this case. There are two pipelines: supply (this is where the hot the water is flowing to the house) and reverse (cooled water returns to the boiler room).
Diagram of the elevator heating unit
From the thermal chamber, water enters the basement of the house; there is always a shut-off valve at the entrance. Usually these are valves, but sometimes in those systems that are more thought out, they install ball valves made of steel.
As the standards show, there are several thermal regimes in boiler rooms:
- 150/70 degrees;
- 130/70 degrees;
- 95(90)/70 degrees.
When the water heats up to a temperature no higher than 95 degrees, the heat will be distributed throughout the heating system using a collector. But at temperatures above normal - above 95 degrees, everything becomes much more complicated. Water at this temperature cannot be supplied, so it must be reduced. This is precisely the function of the elevator heating unit. We also note that cooling water in this way is the simplest and cheapest way.
Purpose and characteristics
The heating elevator cools the superheated water to the calculated temperature, after which the prepared water enters heating devices, which are located in residential premises. Cooling of water occurs at the moment when hot water from the supply pipeline is mixed with cooled water from the return pipeline in the elevator.
The heating elevator diagram clearly shows that this unit helps to increase the efficiency of the entire heating system of the building. It is assigned two functions at once - a mixer and circulation pump. Such a unit is inexpensive and does not require electricity. But the elevator also has several disadvantages:
- The pressure difference between the direct and reverse supply pipelines should be 0.8-2 Bar.
- The output temperature cannot be adjusted.
- There must be an accurate calculation for each elevator component.
Elevators are widely used in municipal heating systems, since they are stable in operation when the thermal and hydraulic conditions in heating networks change. The heating elevator does not require constant monitoring; all regulation consists of choosing the correct nozzle diameter.
The heating elevator consists of three elements - a jet elevator, a nozzle and a vacuum chamber. There is also such a thing as elevator piping. The necessary shut-off valves, control thermometers and pressure gauges must be used here.
Today you can find elevator units of the heating system that can electrically adjust the diameter of the nozzle. Thus, it will be possible to automatically regulate the temperature of the coolant.
The selection of a heating elevator of this type is due to the fact that here the mixing coefficient varies from 2 to 5, in comparison with conventional elevators without nozzle regulation, this indicator remains unchanged. Thus, in the process of using elevators with an adjustable nozzle, heating costs can be slightly reduced.
The design of this type of elevator includes a regulating actuator that ensures stable operation of the heating system at low flow rates of network water. The cone-shaped nozzle of the elevator system houses a regulating throttle needle and a guide device, which spins the water stream and plays the role of a throttle needle casing.
This mechanism has a gear shaft rotating either electrically or manually. It is designed to move the throttle needle in the longitudinal direction of the nozzle, changing its effective cross-section, after which the water flow is regulated. Thus, you can increase the consumption of network water from the calculated indicator by 10-20%, or reduce it almost until the nozzle is completely closed. Reducing the nozzle cross-section can lead to an increase in the flow rate of network water and the mixing coefficient. This way the water temperature decreases.
Malfunctions of heating elevators
The diagram of the elevator heating unit may have faults that are caused by a breakdown of the elevator itself (clogging, an increase in the diameter of the nozzle), clogging of the mud traps, breakdown of fittings, or violations of the regulator settings.
The breakdown of an element such as a heating elevator device can be noticed by the way temperature differences appear before and after the elevator. If the difference is large, then the elevator is faulty; if the difference is insignificant, then it may be clogged or the nozzle diameter may be increased. In any case, diagnosis of the breakdown and its elimination should only be carried out by a specialist!
If the elevator nozzle becomes clogged, it is removed and cleaned. If the design diameter of the nozzle increases due to corrosion or arbitrary drilling, then the circuit of the elevator heating unit and the heating system as a whole will become unbalanced.
Devices installed on the lower floors will overheat, and those on the upper floors will not receive enough heat. Such a malfunction, which the operation of the heating elevator undergoes, is eliminated by replacing it with a new nozzle with the calculated diameter.
Elevator units have been used in heating units of apartment buildings since the middle of the last century, and some examples continue to operate successfully to this day. Residents are in no hurry to replace obsolete elements with new fittings equipped with modern automation, and this reluctance is completely justified. To clarify the essence of the issue, we suggest understanding what an elevator is, its structure and the main functions in the heating system.
Purpose and functions of the node
Water in centralized heating networks reaches a temperature of 150 °C and moves through external pipelines under a pressure of 6-10 Bar. Why are such high coolant parameters maintained:
- So that high-temperature boilers or other thermal power equipment operate with maximum efficiency.
- To deliver heated water to areas remote from a boiler house or thermal power plant, network pumps must create a decent pressure. Then at the thermal inputs of nearby buildings the pressure reaches 10 Bar (pressure testing - 12 Bar).
- Transportation of superheated coolant is economically beneficial. A ton of water brought to 150 degrees contains significantly more thermal energy than the same volume at 90 °C.
The detail is simple - it looks like an ordinary tee with flangesReference. The coolant in the pipes does not turn into steam because it is under pressure, holding the water in the liquid state of aggregation.
According to current regulatory documents, the temperature of the coolant supplied to the water heating system of a residential or administrative building should not exceed 95 °C. And the pressure of 8-10 atmospheres is too high for. This means that the specified water parameters need to be adjusted downward.
An elevator is a non-volatile device that lowers the pressure and temperature of the incoming coolant by mixing cooled water coming from the heating system. The element shown in the photo above is part of the thermal unit circuit and is installed between the supply and return pipelines.
The third function of the elevator is to ensure the circulation of water in the house circuit (usually a single-pipe system). That is why this element is of interest - despite its apparent simplicity, it combines 3 devices - a pressure regulator, a mixing unit and a water-jet circulation pump.
Elevator element with replaceable nozzle The principle of operation of the elevator
Externally, the design resembles a large tee made of metal pipes with connecting flanges at the ends. How the elevator works inside:
- the left nozzle (see drawing) is a tapering nozzle of the calculated diameter;
- behind the nozzle there is a cylindrical mixing chamber;
- the lower pipe is used to connect the return line to the mixing chamber;
- the right pipe is an expanding diffuser that directs coolant into the heating network of a multi-story building.
In the drawing, the ejected flow pipe is conventionally shown at the top, although it is usually located at the bottom Note. In the classic version, the elevator does not require connection to the house electrical network. An updated version of the product with an adjustable nozzle and an electric drive is connected to an external power source.
The steel elevator unit is connected by the left branch pipe to the supply line of the centralized heating network, and by the bottom branch pipe to the return pipeline. Shut-off valves are installed on both sides of the element, plus a mesh filter - a sump (otherwise known as a sludge tank) on the supply. The traditional scheme of a heating point with an elevator also includes pressure gauges, thermometers (on both lines) and.
Now let's look at how the elevator jumper works:
- Superheated water from the heating network passes through the left pipe to the nozzle.
- At the moment of passing through the narrow section of the nozzle under high pressure, the flow accelerates according to Bernoulli's law. The effect of a water jet pump begins to operate, ensuring the circulation of coolant in the system.
- In the area of the mixing chamber, the water pressure decreases to normal.
- The jet moving at high speed into the diffuser creates a vacuum in the mixing chamber. An ejection effect occurs - a flow of liquid with a higher pressure entrains the coolant returning from the heating network through the jumper.
- In the heating elevator chamber, the cooled water is mixed with superheated water, and at the outlet of the diffuser we obtain the coolant at the required temperature (up to 95 °C).
Clarification. It is worth noting that the elevator unit also uses the injection principle in its operation - mixing two jets with simultaneous transfer of energy. The pressure of the resulting flow becomes less than the initial one, but more than that sucked from the return. The process is shown more clearly in the video:
The main condition for normal operation of the elevator is a sufficient pressure difference between the main supply and the return line. This difference should be enough to overcome the hydraulic resistance of the home heating system and the injector itself. Please note: the vertical jumper cuts into the return at an angle of 45° for better flow separation.
At the supply from the heating network, the pressure is highest, at the outlet from the diffuser - average, in the return line - the lowest. The same thing happens in the elevator with water temperature Technical characteristics of standard products
The line of factory-made elevators consists of 7 standard sizes, each assigned a number. When selecting, 2 main parameters are taken into account - the diameter of the neck (mixing chamber) and the working nozzle. The latter is a removable cone, which can be changed if necessary.
See the table below for the dimensions of the component elements of the product. The nozzle is replaced in two cases:
- When the flow area of a part increases as a result of natural wear. The reason for the development is the friction of abrasive particles contained in the coolant.
- If it is necessary to change the mixing coefficient, increase or decrease the temperature of the water supplied to the house heating system.
The numbers of standard elevators and main dimensions are given in the table (compare with the designations on the drawing).
Please note: the technical specifications do not indicate the nozzle flow area, since this diameter is calculated separately. To select the number of the finished elevator tee for a specific heating system, it is also necessary to calculate the required size of the mixing and injection chamber.
Calculation and selection of elevator by number
Let’s immediately clarify the procedure: first of all, the diameter of the mixing chamber is calculated and the appropriate elevator number is selected, then the size of the working nozzle is determined. The diameter of the injection chamber (in centimeters) is calculated by the formula:
The indicator Gpr participating in the formula is the real coolant flow rate in the system of an apartment building, taking into account its hydraulic resistance. The value is calculated as follows:
- Q – amount of heat consumed to heat the building, kcal/h;
- Tcm is the temperature of the mixture at the outlet of the elevator tee;
- Т2о – water temperature in the return line;
- h is the resistance of the entire heating wiring together with radiators, expressed in meters of water column.
Reference. To insert unknown kilocalories into the formula, you need to multiply the familiar watts by a factor of 0.86. Meters of water column are converted to the more common units: 10.2 m water. Art. = 1 Bar.
An example of selecting an elevator number. We found out that the actual consumption Gpr will be 10 tons of mixed water in 1 hour. Then the diameter of the mixing chamber is 0.874 √10 = 2.76 cm. It is logical to take mixer No. 4 with a 30 mm chamber.
Now we find out the diameter of the narrow part of the nozzle (in millimeters) using the following formula:
- Dr – previously determined size of the injection chamber, cm;
- u – mixing coefficient;
- Gpr is our consumption of the finished coolant when supplied to the system.
Although the formula seems cumbersome on the surface, in reality the calculations are not too complicated. One parameter remains unknown - the injection coefficient, calculated as follows:
We have deciphered all the notations from this formula, except for parameter T1 – the temperature of hot water at the entrance to the elevator. If we assume that its value is 150 degrees, and the supply and return temperatures are 90 and 70 °C, respectively, the required size Dc will be 8.5 mm (at a flow rate of 10 t/h of water).
When the pressure value Нр at the entrance to the elevator from the central side is known, you can use an alternative formula for determining the diameter:
Comment. The result of the calculation using the last formula is expressed in centimeters.
In conclusion about the disadvantages of elevator mixers
We found out earlier the positive aspects of using elevators in home heating units - energy independence, simplicity, operational reliability and durability. Now about the disadvantages:
- For normal operation of the system, it is necessary to ensure a significant difference in water pressure between return and supply.
- An individual selection of a unit for a specific heating network, based on calculations, is required.
- To change the parameters of the exiting coolant, you need to recalculate the diameter of the nozzle hole to the new conditions and replace the nozzle.
- Smooth temperature control at the elevator is not provided.
- The unit cannot be used as a circulation pump in a local circuit (for example, in a private house).
Clarification. There are improved models of elevators with adjustable flow area. A cone is installed inside the prechamber, moved by a gear transmission; the drive is manual or electric. True, the main advantage of the node is lost - independence from electricity.
Single-pipe house systems operating in conjunction with elevators are quite difficult to put into operation. It is necessary first from the return riser, then from the supply, gradually opening the main valve. The master plumber will tell you more about the injection units and the start-up method in the video:
Providing residential buildings and public buildings heat is one of the most important tasks of municipal services in cities and towns. Modern ones are complex complexes that included heat suppliers (CHP or boiler houses), an extensive network of main pipelines, special distribution heat points, from which there are branches to end consumers.
However, the coolant supplied through pipes to buildings does not directly enter the intra-house network and the end points of heat exchange - heating radiators. Any house has its own heating unit, in which the pressure level and water temperature are adjusted accordingly. There are special devices installed here that perform this task. Recently, modern electronic equipment has been increasingly installed, which allows automatic monitoring of the necessary parameters and making appropriate adjustments. The cost of such complexes is very high, they directly depend on the stability of the power supply, so organizations that operate housing stock often give preference to the old proven scheme of local regulation of the coolant temperature at the entrance to the house network. And the main element of such a scheme is the elevator unit of the heating system.
The purpose of this article is to provide an understanding of the structure and operating principle of the elevator itself, its place in the system and the functions it performs. In addition, interested readers will receive a lesson on how to independently calculate this node.
General brief information about heat supply systems
In order to correctly understand the importance of the elevator unit, it is probably necessary to first briefly consider how central heating systems work.
The source of thermal energy is thermal power plants or boiler houses, in which the coolant is heated to the required temperature through the use of one or another type of fuel (coal, petroleum products, natural gas etc.) From there the coolant is pumped through pipes to points of consumption.
A thermal power plant or a large boiler house is designed to provide heat to a certain area, sometimes covering a very large territory. Pipeline systems turn out to be very long and branched. How to minimize heat loss and distribute it evenly among consumers, so that, for example, the buildings most distant from the thermal power plant do not experience a shortage of it? This is achieved by careful thermal insulation of heating lines and maintaining a certain thermal regime in them.
In practice, several theoretically calculated and practically tested temperature regimes for the operation of boiler houses are used, which ensure heat transfer over significant distances without significant losses, and maximum efficiency and economical operation of boiler equipment. So, for example, modes 150/70, 130/70, 95/70 are used (water temperature in the supply line / return temperature). The choice of a specific mode depends on the climate zone of the region and on the specific level of the current winter air temperature.
1 – Boiler house or thermal power plant.
2 – Consumers of thermal energy.
3 – Heated coolant supply line.
4 – “Return” highway.
5 And 6 – Branches from highways to consumer buildings.
7 – In-house heat distribution units.
From the supply and return mains there are branches to each building connected to this network. But here questions immediately arise.
- Firstly, different objects require different amounts of heat - you cannot compare, for example, a huge residential high-rise and a small low-rise building.
- Secondly, the temperature of the water in the main does not meet the permissible standards for supply directly to the heat exchange devices. As can be seen from the above modes, the temperature very often even exceeds the boiling point, and water is maintained in a liquid aggregate state only due to high pressure and the tightness of the system.
The use of such critical temperatures in heated rooms is unacceptable. And it’s not just a matter of excess thermal energy supply – this is extremely dangerous. Any touch to batteries heated to this level will cause severe tissue burns, and in the event of even a slight depressurization, the coolant instantly turns into hot steam, which can lead to very serious consequences.
The correct choice of heating radiators is extremely important!
Not all heating radiators are the same. It’s not only and not so much about the material of manufacture and appearance. They can differ significantly in their performance characteristics and adaptation to a particular heating system.
How to approach
Thus, at the local heating unit of the house it is necessary to reduce the temperature and pressure to the calculated operating levels, while ensuring the required heat extraction sufficient for the heating needs of a particular building. This role is performed by special heating equipment. As already mentioned, these can be modern automated complexes, but very often preference is given to a proven elevator unit scheme.
If you look at the heat distribution point of a building (most often they are located in the basement, at the entry point of the main heating networks), you will see a node in which a jumper is clearly visible between the supply and return pipes. This is where the elevator itself stands; the structure and principle of operation will be discussed below.
How a heating elevator works and works
Externally, the heating elevator itself is a cast iron or steel structure, equipped with three flanges for insertion into the system.
Let's look at its structure inside.
Superheated water from the heating main enters the inlet pipe of the elevator (item 1). Moving forward under pressure, it passes through a narrow nozzle (item 2). A sharp increase in the flow velocity at the nozzle exit leads to an injection effect - a vacuum zone is created in the receiving chamber (item 3). According to the laws of thermodynamics and hydraulics, water is literally “sucked” into this area of low pressure from the pipe (item 4) connected to the “return” pipe. As a result, in the mixing neck of the elevator (item 5), the hot and cooled flows are mixed, the water receives the temperature required for the internal network, the pressure decreases to a level safe for heat exchange devices, and then the coolant through the diffuser (item 6) enters the internal distribution system .
In addition to lowering the temperature, the injector acts as a kind of pump - it creates T t is the required water pressure, which is necessary to ensure its circulation in the intra-house wiring, overcoming the hydraulic resistance of the system.
As you can see, the system is extremely simple, but very effective, which determines its widespread use even in competition with modern high-tech equipment.
Of course, the elevator needs a certain piping. An approximate diagram of the elevator unit is shown in the diagram:
Heated water from the heating main enters through the supply pipe (item 1), and returns to it through the return pipe (item 2). The intra-house system can be disconnected from the main pipes using valves (item 3). All assembly of individual parts and devices is carried out using flange connections(pos. 4).
The control equipment is very sensitive to the purity of the coolant, therefore, mud filters (item 5), direct or “oblique” type, are installed at the inlet and outlet of the system. They settle T solid insoluble inclusions and dirt trapped in the pipe cavity. The mud ponds are periodically cleaned from collected sediments.
“Mud filters”, direct (from below) and “oblique” type Control and measuring instruments are installed in certain areas of the unit. These are pressure gauges (item 6) that allow you to control the level of liquid pressure in the pipes. If the pressure at the inlet can reach 12 atmospheres, then at the exit from the elevator unit it is significantly lower, and depends on the number of floors of the building and the number of heat exchange points in it.
There must be temperature sensors - thermometers (item 7) that monitor the temperature level of the coolant: at the inlet of their central - t c, entering the intra-house system - t s, on the “returns” of the system and the central line - t OS and t ots.
Next, the elevator itself is installed (item 8). The rules for its installation require the presence of a straight section of the pipeline of at least 250 mm. With one inlet pipe it is connected through a flange to the supply pipe from the central line, and with the opposite one – to the house distribution pipe (item 11). The lower pipe with a flange is connected through a jumper (pos. 9) to the “return” pipe (pos. 12).
To carry out preventive or emergency repair work, valves are provided (item 10), which completely disconnect the elevator unit from the intra-house network. Not shown in the diagram, but in practice there are always special elements for drainage - drain water from the intra-house system if such a need arises.
Of course, the diagram is given in a very simplified form, but it fully reflects the basic structure of the elevator unit. Wide arrows show the directions of coolant flows at different temperature levels.
The undeniable advantages of using an elevator unit to regulate the temperature and pressure of the coolant are:
- Simplicity of design with trouble-free operation.
- Low cost of components and their installation.
- Complete energy independence of such equipment.
- The use of elevator units and heat metering devices makes it possible to achieve savings in the consumption of coolant consumed up to 30%.
There are, of course, very significant disadvantages:
- Each system requires individual calculation to select the required elevator.
- The need for a mandatory pressure difference at the inlet and outlet.
- Impossibility of precise smooth adjustments with current changes in system parameters.
The last drawback is quite conditional, since in practice elevators are often used, which provide for the possibility of changing its operating characteristics.
To do this, a special needle is installed in the receiving chamber with a nozzle (item 1) - a cone-shaped rod (item 2), which reduces the cross-section of the nozzle. This rod is in the kinematics block (pos. 3) through a rack and pinion gear (pos. 4 — 5) connected to the adjusting shaft (item 6). The rotation of the shaft causes the cone to move in the nozzle cavity, increasing or decreasing the clearance for the passage of liquid. Accordingly, the operating parameters of the entire elevator unit change.
Depending on the level of automation of the system, various types of adjustable elevators can be used.
Thus, the transmission of rotation can be carried out manually - the responsible specialist monitors the readings of instrumentation and makes adjustments to the operation of the system, focusing on on a scale carried near the flywheel (handle).
Another option is when the elevator unit is connected to an electronic monitoring and control system. The readings are taken automatically, the control unit generates signals to transmit them to servos, through which the rotation is transmitted to the kinematic mechanism of the adjustable elevator.
What you need to know about coolants?
In heating systems, especially in autonomous ones, not only water can be used as a coolant.
What qualities should it have and how to choose it correctly - in a special publication on the portal.
Calculation and selection of heating system elevator
As already mentioned, each building requires a certain amount of thermal energy. This means that a certain calculation of the elevator is necessary, based on the given operating conditions of the system.
The initial data includes:
- Temperature values:
— at the entrance of their heating plant;
— in the “return” of the heating plant;
— operating value for the indoor heating system;
- in the return pipe of the system.
- The total amount of heat required to heat a particular house.
- Parameters characterizing features.
The procedure for calculating an elevator is established by a special document - “Code of Rules for the Design of the Ministry of Construction of the Russian Federation”, SP 41-101-95, which relates specifically to the design of heating points. This regulatory manual contains calculation formulas, but they are quite “heavy”, and there is no particular need to present them in the article.
Those readers who are little interested in calculation issues can safely skip this section of the article. And for those who want to independently calculate the elevator unit, we can recommend spending 10 ÷ 15 minutes of time to create your own calculator based on the joint venture formulas, which allows you to make accurate calculations in literally a matter of seconds.
Creating a calculator for calculation
To work, you will need the usual Excel application, which probably every user has - it is included in the basic Microsoft Office software package. Creating a calculator will not be particularly difficult even for those users who have never encountered basic programming issues.
Let's look at it step by step:
(if some of the text in the table goes beyond the frame, then there is a “slide” at the bottom for horizontal scrolling)
| Illustration | Brief description of the operation performed |
|---|---|
 | Open a new file (workbook) in Excel in Microsoft Office. In a cell A1 type the text “Calculator for calculating the elevator of the heating system.” Below, in the cell A2 We type “Initial data”. Inscriptions can be “raised” by changing the boldness, size or color of the font. |
 | Below there will be lines with cells for entering initial data, on the basis of which the elevator will be calculated. Filling the cells with text A3 By A7: A3– “Coolant temperature, degrees C:” A4– “in the supply pipe of the heating plant” A5– “in the return of the heating plant” A6– “necessary for an in-house heating system” A7– “in the return of the heating system” |
 | For clarity, you can skip the line, and below, in the cell A9 enter the text “Required amount of heat for the heating system, kW” |
 | We skip another line, and into the cell A11 type “Resistance coefficient of the home heating system, m.” To get text from a column A didn't find the column IN, where the data will be entered in the future, column A can be expanded to the required width (shown by the arrow). |
 | Data entry area, from A2-B2 to A11-B11 You can select it and fill it with color. So it will be different from the other area where the calculation results will be displayed. |
 | Skip another line and enter into the cell A13"Calculation results:" You can highlight text in a different color. |
 | Next, the most crucial stage begins. In addition to entering text into column cells A, in adjacent cells of a column IN formulas are entered in accordance with which calculations will be carried out. Formulas should be transferred exactly as indicated, without any extra spaces. Important: the formula is entered in the Russian keyboard layout, with the exception of cell names - they are entered exclusively in Latin layout In order not to make a mistake with this, in the given examples of formulas, the cell names will be highlighted in bold. So, in the cell A14 We type the text “Temperature difference of the heating plant, degrees C.” to cell B14 add the following expression =(B4-B5) It is more convenient to enter and control its correctness in the formula bar (green arrow). Don't be confused by what's in the box B14 some value immediately appears (in this case, “0”, blue arrow), the program simply processes the formula immediately, relying on empty input cells for now. |
 | Fill in the next line. In a cell A15– the text “Temperature difference of the heating system, degrees C”, and in the cell B15– formula =(B6-B7) |
 | Next line. In a cell A16– text: “Required performance of the heating system, cubic m/hour.” Cell B16 should contain the following formula: =(3600*B9)/(4,19*970*B14) An error message will appear, “division by zero” - don’t pay attention, this is simply because the original data has not been entered. |
 | Let's go lower. In a cell A17– text: “Elevator mixing coefficient.” Nearby, in a cell B17– formula: =(B4-B6)/(B6-B7) |
 | Next, cell A18– “Minimum coolant pressure in front of the elevator, m.” Formula in cell B18: =1,4*B11*(DEGREE((1+ B17);2)) Don't go astray with the number of brackets - this is important |
 | Next line. In a cell A19 text: “Elevator neck diameter, mm.” Formula in cell B18 next: =8.5*DEGREE((DEGREE( B16;2)*DEGREE(1+ B17;2))/B11;0,25) |
 | And the last line of calculations. In a cell A20 enter the text “Elevator nozzle diameter, mm.” In a cell B20– formula: =9.6*DEGREE(DEGREE( B16;2)/B18;0,25) |
 | Basically, the calculator is ready. You can only modernize it a little so that it is more convenient to use, and there is no risk of accidentally deleting the formula. First, let's select the area from A13-B13 to A20-B20, and fill it with a different color. The fill button is shown with an arrow. |
 | Now select general area With A2-B2 By A20-B20. In the drop down menu "borders"(shown by arrow) select the item "all borders". Our table receives a harmonious frame with lines. |
 | Now we need to make sure that values can be manually entered only into those cells that are intended for this (so as not to erase or accidentally break formulas). Select the range of cells from B4 to B11(red arrows). Go to the menu "format"(green arrow) and select the item "cell format"(blue arrow). |
 | In the window that opens, select the last tab – “protection” and uncheck the “protected cell” box. |
 | Now let's go to the menu again "format", and select the item in it "protect sheet". |
 | A small window will appear in which you just need to press the button "OK". We simply ignore the prompt to enter a password - our document does not need such a degree of protection. Now you can be sure that there will be no failure - only the cells in the column are open for changes IN in the value entry area. If you try to add anything to any other cells, a window will appear warning you that such an operation is impossible. |
 | The calculator is ready. All that remains is to save the file. – and he will always be ready to carry out calculations. |
Carrying out calculations in the created application is not difficult. You just need to fill the input area with known values - then the program will calculate everything automatically.
- The supply and return temperatures in the heating plant can be found in the heating station (boiler room) closest to the house.
- The required temperature of the coolant in the intra-house system largely depends on what heat exchange devices are installed in the apartments.
- The temperature in the “return” pipe of the system is most often assumed to be equal to the same indicator in the central line.
- The house’s need for a general influx of thermal energy depends on the number of apartments, heat exchange points (radiators), the characteristics of the building - the degree of its insulation, the volume of premises, the amount of total heat loss, etc. Typically, these data are calculated in advance at the design stage of a house or during the reconstruction of its heating system.
- The resistance coefficient of the internal heating circuit of a house is calculated using separate formulas, taking into account the characteristics of the system. However, it would not be a big mistake to take the average values given in the table below:
| Types of multi-apartment residential buildings | Coefficient value, m |
|---|---|
| Old-built apartment buildings with heating circuits made of steel pipes, without temperature and coolant flow regulators on risers and radiators. | 1 |
| Houses put into operation or in which major repairs were carried out before 2012, with the installation of polypropylene pipes on the heating system, without temperature and coolant flow regulators on risers and radiators | 3 ÷ 4 |
| Houses put into operation or after major renovations after 2012, with the installation of polypropylene pipes on the heating system, without temperature and coolant flow regulators on risers and radiators. | 2 |
| The same thing, but with installed temperature and coolant flow control devices on risers and radiators | 4 ÷ 6 |
Carrying out calculations and selecting the desired elevator model
Let's try the calculator in action.
Let’s assume that the temperature in the supply pipe of the heating plant is 135, and in the return pipe – 70 °C. It is planned to maintain a temperature of 85 ° in the heating system of the house WITH, at the outlet – 70 °C. For high-quality heating of all rooms, a thermal power of 80 kW is required. According to the table, it is determined that the resistance coefficient is “1”.
We substitute these values into the corresponding lines of the calculator, and immediately get the necessary results:
As a result, we have the data for selecting the required elevator model and the conditions for its correct operation. Thus, the required system performance was obtained - the amount of coolant pumped per unit time, the minimum pressure of the water column. And the most basic quantities are the diameters of the elevator nozzle and its neck (mixing chamber).
The nozzle diameter is usually rounded down to hundredths of a millimeter (in this case, 4.4 mm). The minimum diameter value should be 3 mm - otherwise the nozzle will simply clog quickly.
The calculator allows you to “play” with the values, that is, see how they will change when the initial parameters change. For example, if the temperature in a heating plant is reduced, say, to 110 degrees, then this will affect other parameters of the unit.
As you can see, the diameter of the elevator nozzle is already 7.2 mm.
This makes it possible to select a device with the most acceptable parameters, with a certain range of adjustments, or a set of replacement nozzles for a specific model.
Having the calculated data, you can already refer to the tables of manufacturers of such equipment to select the required version.
Typically, in these tables, in addition to the calculated values, other parameters of the product are given - its dimensions, flange sizes, weight, etc.
For example, water-jet steel elevators of the series 40s10bk:
Flanges: 1 - at the entrance, 1— 1 – on the insertion of the pipe from the “return”, 1— 2 - on the way out.
2 – inlet pipe.
3 – removable nozzle.
4 – receiving chamber.
5 – mixing neck.
7 – diffuser.
The main parameters are summarized in the table for ease of selection:
| Number elevator | Dimensions, mm | Weight, kg | Exemplary water consumption from the network, t/h |
|||||||
|---|---|---|---|---|---|---|---|---|---|---|
| dc | dg | D | D1 | D2 | l | L1 | L | |||
| 1 | 3 | 15 | 110 | 125 | 125 | 90 | 110 | 425 | 9,1 | 0,5-1 |
| 2 | 4 | 20 | 110 | 125 | 125 | 90 | 110 | 425 | 9,5 | 1-2 |
| 3 | 5 | 25 | 125 | 160 | 160 | 135 | 155 | 626 | 16,0 | 1-3 |
| 4 | 5 | 30 | 125 | 160 | 160 | 135 | 155 | 626 | 15,0 | 3-5 |
| 5 | 5 | 35 | 125 | 160 | 160 | 135 | 155 | 626 | 14,5 | 5-10 |
| 6 | 10 | 47 | 160 | 180 | 180 | 180 | 175 | 720 | 25 | 10-15 |
| 7 | 10 | 59 | 160 | 180 | 180 | 180 | 175 | 720 | 34 | 15-25 |
In this case, the manufacturer allows you to independently replace the nozzle with the required diameter within a certain range:
| Elevator model, no. | Possible range of nozzle change, Ø mm |
|---|---|
| №1 | min 3 mm, max 6 mm |
| №2 | min 4 mm, max 9 mm |
| №3 | min 6 mm, max 10 mm |
| №4 | min 7 mm, max 12 mm |
| №5 | min 9 mm, max 14 mm |
| №6 | min 10 mm, max 18 mm |
| №7 | min 21 mm, max 25 mm |
Selecting the required model, having the calculation results in hand, will not be difficult.
When installing an elevator or carrying out maintenance work, it is necessary to take into account that the efficiency of the unit directly depends on the correct installation and integrity of the parts.
Thus, the nozzle cone (glass) must be installed strictly coaxially with the mixing chamber (neck). The glass itself must fit freely into the elevator seat so that it can be removed for inspection or replacement.
When conducting audits, you should pay attention special attention on the condition of the surfaces of the elevator sections. Even the presence of filters does not exclude the abrasive effect of the liquid, plus there is no escape from erosion processes and corrosion. The working cone itself must have a polished inner surface, smooth, unworn edges of the nozzle. If necessary, it is replaced with a new part.
Failure to comply with such requirements entails a decrease in the efficiency of the unit and a drop in the pressure required for the circulation of the coolant in the intra-house heating distribution. In addition, the nozzle is worn out, dirty or too large diameter(significantly higher than calculated) will lead to the appearance of strong hydraulic noise, which will be transmitted through the heating pipes to the residential premises of the building.
Of course, a home heating system with a simple elevator unit is far from being an example of perfection. It is very difficult to adjust, which requires disassembling the unit and replacing the injection nozzle. Therefore, the best option seems to be modernization with the installation of adjustable elevators, which allow changing the coolant mixing parameters within a certain range.
How to regulate the temperature in the apartment?
The temperature of the coolant in the intra-house network may be excessive for a single apartment, for example, if it uses “warm floors”. This means that you will need to install your own equipment, which will help maintain the heating level at the desired level.
Options, how - in a special article on our portal.
And finally, a video with computer visualization of the device and operating principle of the heating elevator:
Video: design and operation of a heating elevator