For heating systems in residential premises, there is a standard coolant temperature. In accordance with established norm the temperature of the water that enters the radiators should not exceed +95 degrees. But heating networks can supply coolant whose temperature exceeds this indicator and ranges from 130 to 150 degrees. Therefore, it is necessary to lower the water temperature to the required value. The solution to this problem is assigned to the elevator heating unit.

This is what an elevator for a heating system looks like

The elevator works in this way: the coolant from the main line is supplied to a removable conical nozzle, in which the speed of water movement increases and, as a result, a stream of water from the nozzle enters the mixing chamber, where it mixes with cooled water that enters there through a jumper from the return pipeline.

After mixing the superheated main water and cooled water, the coolant of the required temperature enters the heating system and heating devices. And in order to prevent large particles from entering the elevator, a mud trap is installed in front of the device.

Elevators have become widespread due to their stable operation aimed at changing thermal and hydraulic conditions in heating networks.

Elevator heating units do not require constant monitoring. Their performance is regulated the right choice nozzle diameter. To select the dimensions, the diameter of the elevator assembly pipes and the diameter of the nozzle, you must contact a design office with the appropriate competence.

Now let's look in more detail at how the elevator heating system works and whether it is possible to do without this device.

Diagram of an elevator heating unit

The elevator assembly diagram for the heating system looks like this.

Here we see that this diagram includes a supply heat pipe (No. 1), as well as a return heat pipe (No. 2), other components of the elevator assembly are valves (No. 3), a water meter (No. 4), mud traps (No. 5), pressure gauges and thermometers numbered 6 and 7, and, of course, the elevator itself (8) and heating devices (9).

Elevator unit diagram

The diagram below shows the simplest basic configuration of an elevator unit. But if necessary, the elevator unit can be supplemented with other elements: regulators, branches of primary and secondary coolants, filters, metering devices, etc.

The principle of operation of the elevator unit in the heating system

The operation of the elevator unit consists of several stages:

1. Water from the main network enters the nozzle, which is narrowed at the outlet, and is accelerated due to the pressure difference.
2. Superheated water comes out of the nozzle with reduced pressure and high speed. As a result, a vacuum is created and water is sucked into the elevator from the return pipeline.
3. The amount of both superheated and reverse cooled water is regulated so that the temperature of the water leaving the elevator unit corresponds to the design value.

We figured out that the elevator unit, located at the inlet to the local heating system, reduces the temperature of the coolant, which is supplied from the central main network to the local heating system, this happens by mixing return water.

Now let's look at what consequences can be expected local sewerage, if the elevator unit is not installed.

Is an elevator needed in a heating system?

The elevator is a water-jet pump, which, due to the pressure difference, increases the pumping of coolant in the internal heating system. That is, it takes a certain amount of water from the main network, dilutes it with cooled return water from the local heating system and sends it again to heating radiators to heat apartments.

Now let's see what can happen to our heating without this the required device. If water above 130 degrees enters the heating system, then in apartments located at the beginning heating system, it will be very hot, and in the apartments located a little further away, the temperature will be stably low.

Water cannot be supplied from high temperature(over 130 degrees) in cast iron batteries, which can burst if there is a sharp change in temperature. For polypropylene pipes, which are now widely installed in heating systems, operating water temperatures above 95 degrees are unacceptable. For a short time, polypropylene can withstand temperatures of 100 degrees.

From all this we can conclude that the elevator unit is vital for our heating system.

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 heating elevator operating principle would be multi-storey building. It's in the basement multi-storey building Among all the elements you can find an elevator.

First of all, let's consider what kind of in this case has an elevator heating unit drawing. There are two pipelines: supply (precisely through it hot water goes to the house) and reverse (cooled water returns to the boiler room).

Diagram of an elevator heating unit

From the thermal chamber, water enters the basement of the house; at the entrance there must be shut-off valves. Usually these are valves, but sometimes in those systems that are more thought out, steel ball valves are installed.

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 design 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 a 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 the municipal heating sector, since they are stable in operation when the thermal and hydraulic mode. 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 costs 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 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.

Clogging of the sump in a device such as an elevator in a heating system can be determined by the increase in the pressure difference, monitored by pressure gauges before and after the sump. Such clogging is removed by discharging dirt through the drain valves of the sludge tank, which are located in its lower part. If the blockage is not removed this way, then the mud trap is disassembled and cleaned from the inside.

The elevator unit of the heating system is used to connect the house to an external heating network (heat supply source) if it is necessary to reduce the temperature of the coolant by mixing water from the return pipeline.

Features and Specifications

At correct installation The elevator unit of the heating system performs circulation and mixing functions. This device has the following advantages:

• Lack of connection to the electrical network.
• Efficiency.
• Simplicity of design.

Flaws:

• Inability to regulate outlet temperature.
• Accurate calculation and selection is required.
• A pressure difference must be maintained between the return and supply lines.

Elevator unit of the heating system: diagram

The design of this device provides for the following elements:

• Nozzle.
• Vacuum chamber.
• Jet elevator.

Additionally, the elevator unit of the heating system is equipped with pressure gauges, thermometers and shut-off valves.

As an alternative to this device, you can use equipment with automatic regulation temperature. It is more economical, more energy efficient, but costs much more. And most importantly, this equipment is not able to work in the absence of electricity.

For this reason, the installation of an elevator is relevant today. It is characterized by a number of undeniable advantages, and it will be used by utility companies for a long time.

The role of the elevator unit

Heating of domestic apartment buildings carried out through a centralized heating system. For this purpose, small thermal power plants and boiler houses are being built in small and large cities. Each of these objects produces heat for several houses or neighborhoods. The disadvantage of such a system is significant heat loss.

If the coolant path is too long, it is impossible to regulate the temperature of the transported liquid. For this reason, every home must be equipped with an elevator unit. This will solve many problems: it will significantly reduce heat consumption, and prevent accidents that may occur as a result of power failure or equipment failure.

This question becomes especially relevant in the autumn and spring periods of the year. The coolant is heated in accordance with established standards, but its temperature depends on the outside air temperature.

Thus, the nearest houses, compared to those located further, receive more hot coolant. It is for this reason that the elevator unit of the system is so necessary central heating. It will dilute the overheated coolant cold water and thereby compensates for heat loss.

Operating principle

The elevator unit of the heating system functions as follows:

• From the main network, the coolant is directed into a nozzle narrowed at the outlet, and then, thanks to the pressure difference, it is accelerated.
• The superheated coolant leaves the nozzle at increased speed and with reduced pressure. This creates a vacuum and sucks liquid into the elevator from the return pipeline.
• The amount of superheated and cooled return coolant must be regulated in such a way that the temperature of the liquid leaving the elevator corresponds to the design value.

Elevator unit of the heating system: dimensions

Number	Coolant flow	Neck diameter	Weight	Dimensions
				L	l1	l2	h	Flange 1	Flange 2
0	0.1-0.4 t/hour	10mm	6.4kg	256mm	85mm	81mm	140mm	25mm	32mm
1	0.5-1 t/hour	15mm	8.1kg	425mm	110mm	90mm	110mm	40mm	50mm
2	1-2 t/hour	20mm	8.1kg	425mm	100mm	90mm	110mm	40mm	50mm
3	1-3 t/hour	25mm	12.5kg	625mm	145mm	135mm	155mm	50mm	80mm
4	3-5 t/hour	30mm	12.5kg	625mm	135mm	135mm	155mm	50mm	80mm
5	5-10 t/hour	35mm	13kg	625mm	125mm	135mm	155mm	50mm	80mm
6	10-15 t/hour	47mm	18kg	720mm	175mm	180mm	175mm	80mm	100mm
7	15-25 t/hour	59mm	18.5kg	720mm	155mm	180mm	175mm	80mm	100mm

Kinds

There are two types of these devices:

• Elevators that cannot be regulated.
• Elevators, the operation of which is controlled by an electric drive.

When installing any of them, it is very important to maintain tightness. This equipment is installed in a heating system that is already functioning. Therefore, before installation, it is recommended to study the location where the subsequent placement of this equipment is planned. This type It is recommended to entrust the work to specialists who are able to understand the scheme, as well as develop drawings and perform calculations.

The operating principle of a thermal elevator unit and a water-jet elevator. In the previous article, we found out the basics and operating features of water-jet or, as they are also called, injection elevators. In short, the main purpose of the elevator is to lower the water temperature and at the same time increase the volume of pumped water in internal system heating a residential building.

Now let's figure out how water jet elevator working and due to which it increases the pumping of coolant through the batteries in the apartment.

The coolant enters the house at a temperature appropriate temperature chart boiler room work. Temperature chart this is the relationship between the temperature outside and the temperature that the boiler house or thermal power plant must supply to the heating network, and accordingly, with small losses, to your heating point (water, moving through pipes over long distances, cools down a little). The colder it is outside, the higher the temperature the boiler room produces.

For example, with a temperature chart of 130/70:

• at +8 degrees outside, the heating supply pipe should be 42 degrees;
• at 0 degrees 76 degrees;
• at -22 degrees 115 degrees;

If anyone is interested in more detailed figures, you can download temperature charts for various heating systems.

But let’s return to the principle and operating diagram of our thermal elevator unit.

After passing through inlet valves, mud traps or mesh magnetic filters, the water enters directly into mixing elevator device— elevator, which consists of a steel body, inside of which there is a mixing chamber and a restriction device (nozzle).

Superheated water comes out of the nozzle at high speed. As a result, a vacuum is created in the chamber behind the jet, due to which water is sucked in or injected from the return pipeline. By changing the diameter of the hole in the nozzle, it is possible within certain limits regulate water flow and, accordingly, the temperature of the water leaving the elevator.

Elevator thermal unit works simultaneously as circulation pump and as a mixer. Wherein he doesn't consume electrical energy , but uses the pressure drop in front of the elevator or, as is commonly said, the available pressure in the heating network.

For the elevator to operate efficiently, it is necessary that available head in the heating network was related to the resistance of the heating system no worse than 7 to 1.
If the resistance of the heating system of a standard five-story building is 1 m or 0.1 kgf/cm2, then for normal operation of the elevator unit the available pressure in the heating system up to the ITP is at least 7 m or 0.7 kgf/cm2.

For example, if in the supply pipeline there is 5 kgf/cm2, then in the return pipeline there is no more than 4.3 kgf/cm2.

Please note that at the elevator outlet, the pressure in the supply pipeline is not much greater than the pressure in the return pipeline and this is normal, 0.1 kgf/cm2 is quite difficult to notice on pressure gauges, the quality of modern pressure gauges is unfortunately at a very low level, but this is a topic for a separate article. But if you have a pressure difference after the elevator of more than 0.3 kgf/cm2, you should be wary, or your heating system is heavily clogged with dirt, or when major renovation The diameters of the distribution pipes were greatly underestimated.

The above does not apply to circuits with batteries and risers; only mixing circuits using control valves and mixing pumps work with them.
By the way, the use of these regulators is also very controversial in most cases, since most domestic boiler houses use high-quality regulation according to temperature schedule. In general, mass implementation automatic regulators Danfoss company became possible only thanks to a good marketing campaign. After all, “overtopping” is a very rare phenomenon in our country; usually we don’t get enough heat.

Elevator with adjustable nozzle.

Now we just have to figure it out How can it be easier to regulate the temperature at the elevator outlet?, and is it possible to save heat using an elevator?

It is possible to save heat using a water jet elevator, for example lowering the room temperature at night , or during the day when most of us are at work. Although this issue is also controversial, we lowered the temperature, the building cooled down, therefore, in order to reheat it, the heat consumption must be increased against the norm.
There is only one gain, at a cool temperature of 18-19 degrees you sleep better, our body feels more comfortable.

For heat saving purposes, a special water jet elevator with adjustable nozzle. Structurally, its design and, most importantly, the depth of quality adjustment can be different. Typically, the mixing coefficient of a water-jet elevator with an adjustable nozzle varies in the range from 2 to 5. As practice has shown, such adjustment limits are quite sufficient for all occasions. Danfoss offers a control range of up to 1 in 1000. Why this is used in a heating system is completely unclear to us. But the price ratio in favor of a water jet elevator with an adjustable nozzle relative to Danfoss regulators is approximately 1 to 3. True, we must pay tribute to Danfos, their products are more reliable, although not all of them; some varieties of inexpensive three-way valves do not work well on our water. Recommendation – you need to save wisely!

Fundamentally, all regulating elevators are designed in the same way. Their the device is clearly visible in the figure. , you can see an animated image of the operation of the VARS control mechanism of a water-jet elevator.

And finally, a short comment - application water jet elevators with adjustable nozzle especially effective in public and industrial buildings where it allows you to save up to 20-25% of heating costs by lowering the temperature in heated rooms at night and, especially, on weekends.

At centralized heating Hot water, before entering the heating radiators of apartment buildings, passes through a heating point. There it is brought to the required temperature using special equipment. For this purpose, in the vast majority of home heating units built during the Soviet era, an element such as a heating elevator was installed. This article is intended to tell you what it is and what tasks it performs.

Purpose of the elevator in the heating system

The coolant leaving the boiler room or thermal power plant has a high temperature - from 105 to 150 ° C. Naturally, it is unacceptable to supply water at such a temperature to the heating system.

Regulatory documents limit this temperature to 95 °C and here’s why:

• For safety reasons: you can get burns from touching batteries;
• not all radiators can operate at high temperature conditions, not to mention polymer pipes.

The operation of the heating elevator allows the temperature of the network water to be reduced to a standardized level. You may ask, why can’t water with the required parameters be immediately sent to homes? The answer lies in the plane of economic feasibility; supplying a superheated coolant allows you to transfer a much larger amount of heat with the same volume of water. If the temperature is reduced, then the coolant flow will have to be increased, and then the diameters of the heating network pipelines will increase significantly.

So, the operation of the elevator unit installed in heating point, consists of reducing the water temperature by mixing cooled coolant from the return into the supply pipeline. It should be noted that this element is considered obsolete, although it is still widely used. Nowadays, when constructing heating points, mixing units with three way valves or plate heat exchangers.

How does an elevator work?

If we talk in simple words, then the elevator in the heating system is a water pump that does not require external energy supply. Thanks to this, and even its simple design and low cost, the element found its place in almost all heating points that were built in Soviet time. But for its reliable operation certain conditions are required, as will be discussed below.

To understand the structure of the heating system elevator, you should study the diagram presented in the figure above. The unit is somewhat reminiscent of a regular tee and is installed on the supply pipeline; with its side outlet it is connected to the return line. Only through a simple tee would water from the network pass directly into the return pipeline and directly into the heating system without reducing the temperature, which is unacceptable.

A standard elevator consists of a supply pipe (pre-chamber) with a built-in nozzle of the calculated diameter and a mixing chamber into which cooled coolant is supplied from the return. At the outlet of the assembly, the pipe expands, forming a diffuser. The unit operates as follows:

• coolant from the high-temperature network is directed to the nozzle;
• when passing through a hole of small diameter, the flow speed increases, which is why a rarefaction zone appears behind the nozzle;
• vacuum causes water to be sucked in from the return pipeline;
• the flows are mixed in the chamber and exit into the heating system through a diffuser.

How the described process occurs is clearly shown by the diagram of the elevator unit, where all flows are marked in different colors:

An indispensable condition for stable operation of the unit is that the pressure difference between the supply and return lines of the heating network is greater than the hydraulic resistance of the heating system.

Along with obvious advantages, this mixing unit has one significant drawback. The fact is that the operating principle of the heating elevator does not allow regulating the temperature of the mixture at the outlet. After all, what is needed for this? If necessary, change the amount of superheated coolant from the network and sucked water from the return. For example, in order to reduce the temperature, it is necessary to reduce the supply flow and increase the flow of coolant through the jumper. This can only be achieved by reducing the nozzle diameter, which is impossible.

problem quality regulation Elevators with electric drive help solve this problem. In them, by means of a mechanical drive rotated by an electric motor, the diameter of the nozzle increases or decreases. This is achieved through a cone-shaped throttle needle that enters the nozzle from the inside at a certain distance. Below is a diagram of a heating elevator with the ability to control the temperature of the mixture:

1 – nozzle; 2 – throttle needle; 3 – body actuator with guides; 4 – shaft with gear drive.

Note. The drive shaft can be equipped with either a handle for manual control or an electric motor activated remotely.

Appeared relatively recently adjustable elevator heating system makes it possible to modernize heating units without radically replacing equipment. Considering how many other similar units operate in the CIS, such units are becoming increasingly relevant.

Heating elevator calculation

It should be noted that the calculation of a water jet pump, which is an elevator, is considered quite cumbersome; we will try to present it in an accessible form. So, to select a unit, two main characteristics of elevators are important to us - the internal size of the mixing chamber and the bore diameter of the nozzle. The chamber size is determined by the formula:

• dr – required diameter, cm;
• Gpr – reduced amount of mixed water, t/h.

In turn, the reduced flow rate is calculated as follows:

In this formula:

• τcm – temperature of the mixture used for heating, °C;
• τ20 – temperature of the cooled coolant in the return, °C;
• h2 – resistance of the heating system, m. water. Art.;
• Q – required heat consumption, kcal/h.

To select the elevator unit of the heating system according to the size of the nozzle, it is necessary to calculate it using the formula:

• dr – diameter of the mixing chamber, cm;
• Gpr – reduced consumption of mixed water, t/h;
• u is the dimensionless injection (mixing) coefficient.

The first 2 parameters are already known, all that remains is to find the value of the mixing coefficient:

In this formula:

• τ1 – temperature of the superheated coolant at the entrance to the elevator;
• τcm, τ20 – the same as in the previous formulas.

Note. To calculate the nozzle, you need to take a coefficient u equal to 1.15u’.

Based on the results obtained, the unit is selected according to two main characteristics. Standard sizes elevators are designated by numbers from 1 to 7, you need to take the one that is closest to the design parameters.

Conclusion

Since the reconstruction of all heating points will not happen soon, elevators will serve there as mixers for a long time. Therefore, knowledge of their structure and operating principle will be useful to a certain circle of people.