Elevator unit of the heating system: what it is, how to maintain it and determine the number - the principle of operation of the device, diagram and dimensions

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

What is an elevator unit of a heating system

Trunk heating networks operate in three main modes:

• 95°/70°
• 130°/70°
• 150°/70°

The first number indicates the temperature of the coolant in the forward pipeline, the second – in the return. The coolant is transported over considerable distances, so the temperature is set taking into account the loss of thermal energy during movement and adjusted for climatic or weather conditions. Hence there are three options for supplying coolant - if you constantly heat water to the maximum value, fuel consumption will increase, so heating modes change depending on external conditions.

According to sanitary standards and technical characteristics of household heating equipment, the upper limit of coolant temperature should not exceed 95°. If the water is heated to 130° or 150°, it must be cooled to the set value. There are several reasons for this:

• Most heating devices are not able to work with overheated water - cast iron radiators become brittle, aluminum radiators may fail or cease to maintain system pressure.
• The pipelines used to supply coolant in apartments also have a temperature limit; for example, for plastic pipes a temperature threshold of 90° is set.
• Heating appliances that are too hot are dangerous for people, especially children.

Superheated water does not turn into steam only because there is no such possibility inside the pipelines. It requires the absence of pressure and the presence of free space, which cannot exist in a pipe. Temperature losses during transportation somewhat change the thermal regime of the coolant, but the need to cool it to operating values ​​remains. The issue is resolved by mixing cooled water from the return line until a set temperature is obtained, suitable for use in heating appliances. Mixing of water occurs in special mechanical devices - elevators. They operate in an environment of related elements called the elevator environment, and the entire mixing unit is called the elevator unit.

How is the thermal unit arranged?

In general, the technical structure of each heating point is designed separately depending on the specific requirements of the customer. There are several basic schemes for the design of heating points. Let's look at them one by one.

Thermal unit based on an elevator

The scheme of a heating point based on an elevator unit is the simplest and cheapest. Its main drawback is the inability to regulate the temperature of the coolant in the pipes. This causes inconvenience for the end user and a large overconsumption of thermal energy in the event of thaws during the heating season. Let's look at the figure below and understand how this circuit works:

In addition to what is indicated above, the thermal unit may include a pressure reducer. It is installed on the feed in front of the elevator. The elevator is the main part of this scheme, in which the cooled coolant from the “return” is mixed with the hot coolant from the “supply”. The operating principle of the elevator is based on creating a vacuum at its output. As a result of this vacuum, the coolant pressure in the elevator is less than the coolant pressure in the “return” and mixing occurs.

Thermal unit based on a heat exchanger.

A heating point connected through a special heat exchanger allows you to separate the coolant from the heating main from the coolant inside the house. The separation of coolants allows for its preparation using special additives and filtration. With this scheme, there are ample opportunities to regulate the pressure and temperature of the coolant inside the house. This allows you to reduce heating costs. To have a clear idea of ​​this design, look at the figure below.

The mixing of coolant in such systems is done using thermostatic valves. In such heating systems, in principle, aluminum radiators can be used, but they will last for a long time only if the coolant is of good quality. If the PH of the coolant goes beyond those approved by the manufacturer, then the service life of aluminum radiators may be greatly reduced. You cannot control the quality of the coolant, so it is better to play it safe and install bimetallic or cast iron radiators.

DHW can be connected in a similar way via a heat exchanger. This offers the same benefits in terms of hot water temperature and pressure control. It is worth saying that unscrupulous management companies can deceive consumers by lowering the hot water temperature by a couple of degrees. For the consumer, this is almost unnoticeable, but on a household scale it allows you to save tens of thousands of rubles per month.

Operating principle and device

The elevator is a steel or cast iron body with three pipes (two inlet and one outlet), resembling a regular tee.

General diagram of the elevator unit

The coolant enters the housing and passes through the nozzle, causing its pressure to drop. This causes return flow from the pipeline into the mixing chamber, which ensures circulation in the heating system. The flows, mixing, acquire a given temperature, then are sent through a diffuser to the apartment’s heating system. A conventional elevator is a purely mechanical device, which simplifies its use as much as possible. The adjustment is made by changing the diameter of the nozzle, which creates a certain pressure in the mixing chamber, changing the return suction mode. In this case, the difference in pressure between the forward and return pipelines should not exceed 2 bar. To obtain the correct result, an accurate calculation of the nozzle diameter is required, since this is the only element that is subject to any changes. Otherwise, the elevator is a solid cast iron, relatively inexpensive, reliable and very easy to operate and maintain. These reasons have caused the widespread use of elevators in heating systems of apartment buildings.

There are more complex elevator designs with the ability to change the nozzle diameter. These devices are more expensive and complex, but they allow you to change the operating mode of the heating system on the fly depending on the pressure and temperature of the coolant in the line. The passage of the coolant is regulated by a cone-shaped rod - a needle, which moves in the longitudinal direction and opens or closes the lumen of the nozzle, changing the operating mode of the elevator and the entire system. There is a device with a servo drive, which is capable of adjusting the clearance on the go based on a signal from temperature or pressure sensors, which allows you to fine-tune the operation in automatic mode. Such devices are more expensive and require increased attention and care, but they create a lot of new possibilities for adjusting the system.

Problems connecting to radiators

Any engineering device can start to work incorrectly. The main problems that a person may encounter when connecting radiators and operating an elevator are temperature inconsistencies, improper water flow, noise, blockages, and so on. Below we will look at these main faults in more detail.

Noise

Normally, the elevator should operate fairly quietly. The appearance of noise is usually caused by excessive pressure at the inlet of the device, cracking or corrosion of the nozzle, clogging of the elevator, misalignment of the nozzle, and so on.

Methods for solving this problem can be different:

• If the noise occurs due to a high level of inlet pressure, it is necessary to adjust the pressure in the pipeline section in front of the elevator (for example, using throttling).
• If clogged, the device must be disassembled and cleaned.
• If the noise is due to corrosion or cracking of the nozzle, then the nozzle or the entire elevator must be replaced.

Temperature mismatch

A situation may also arise that you have carried out all the necessary calculations, purchased an elevator, completed the installation, and then it turns out that the temperature does not correspond to the calculations. What's the matter? Most often, this problem occurs due to problems with the nozzle or adjustment needle. The method to solve the temperature discrepancy problem is to replace the nozzle or needle.

Attention! When purchasing, it is advisable to give preference to elevators with regulation. Even if it turns out that the actual situation does not correspond to the expected calculations, you can adjust the temperature and set the desired outlet temperature experimentally

Incorrect accounting and water consumption

Another problem that people often encounter when working with an elevator is incorrect metering or water consumption.

Most often, this problem occurs due to cracking and corrosion of the nozzle, very serious clogging of the elevator, in which case noise also appears.

Pressure sensors at the inlet and outlet show a difference of more than 2 Ba, also in the event of a malfunction of the pressure regulator on any section of the pipe.

This problem can be solved by repairing or replacing damaged parts and cleaning the clogged elevator.

Faulty structural elements

The reasons for this can be different, but the main ones are factory defects of the elevator or malfunction of other elements of the heating network. The way to solve the problem in the first case is to replace the faulty part or the entire device; The way to solve the problem in the second case is to repair the damaged element of the heating network.

Diagram of the elevator unit of the heating system

The elevator cannot operate independently. The elevator unit includes various elements:

• Gate valves (recently they have been replaced by ball valves, which are more convenient and reliable in operation).
• Mudmen.
• Pressure gauges.
• Thermometers.
• Connecting elements (flanges or adapters).

The schematic diagram of the elevator unit can be seen in the figure:

Elevator unit in the heating system: 1- shut-off valves (valve); 2 - mud trap; 3 — water jet elevator; 4 - pressure gauge; 5 - thermometer

The main elements are valves that allow you to adjust the parameters of forward and reverse flow. Mud collectors are devices that separate mechanical inclusions in the form of small debris or dirt. They are subject to periodic cleaning; filling the mud traps is dangerous and can damage elements located further along the flow path. The remaining elements - pressure gauges and thermometers - are control elements and allow you to monitor the current mode of the heating system.

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.

Small elevator heating unit

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!

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.

Maintenance of the elevator heating unit

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.

Elevator unit dimensions

Elevators are manufactured in several standard sizes, corresponding to the size and needs of the heating system of a house or apartment building entrance:

Table depending on the elevator number and its size

The elevator is selected based on a combination of various parameters - temperature, pressure in the system, pipeline capacity, connection dimensions, etc. Most devices are selected based on the diameter of the pipes supplying the heating system. It is important to ensure that the diameter of the supply pipelines matches the dimensions of the elevator pipes so that the device does not turn out to be a kind of diaphragm that reduces the throughput and pressure in the system. In addition, the performance of the nozzle is affected by the size of the nozzle, which must be carefully calculated. Calculation formulas are available online, but it is not recommended to do it yourself without experience and training. The easiest way is to use an online calculator, which can be found on the Internet. It is advisable to check the result obtained on another calculator to get a more correct result.

Composition of a typical elevator

• weight;
• the receiving department (for unloading railway or motor vehicles), is a dam of various volumes of a pass-through or non-pass-through type;
• working tower, it houses machines for preliminary, primary and, if necessary, secondary grain cleaning, as well as an aspiration system for cleaning from light impurities;
• drying compartment, includes containers for storing wet and dry materials, as well as the required number of dryers of various designs with burners for the desired type of fuel;
• the storage compartment in a modern elevator consists of silos (banks) of the required capacity, located either in one row or in several interconnected rows, which allows storing different crops or varieties of the same crops in one elevator;
• The shipping department, as a rule, is a system of hopper bunkers for shipment to railway or road transport;
• transport equipment connects all elevator routes (elevators and conveyors of various types and modifications);
• metal structures (noir towers and transport bridges and galleries);
• electrical and automation systems include control cabinets, frequency converters, sensors, electrical cable products, lighting, etc.;
• administrative building, laboratory, fire tank and other buildings and structures required by regulations.

Advantages of the elevator

Many consumers say that the heating elevator design is irrational, and it is much easier to supply users with coolant at a lower temperature. In fact, this approach involves increasing the diameter of the central heating pipeline to circulate cooler coolant, which implies additional costs.

That is, a high-quality heating unit design allows you to use part of the cooled water from the return flow with the supply volume of coolant. Despite the fact that some elevator sources are outdated hydraulic devices, in fact, they are the most efficient in operation . There are also more modern devices that have replaced elevator unit systems.

This includes the following types of devices:

• mixer equipped with a three-way membrane;
• plate heat exchanger.

Elevator what is it

To understand and understand what this element is, it is best to go down to the basement of the building and see it with your own eyes. But if you have no desire to leave your home, then you can view the photo and video files in our gallery. In the basement, among the many gate valves, pipelines, pressure gauges and thermometers, you will definitely find this unit.

We suggest first understanding the principle of operation. Hot water is supplied to the building from the district boiler house, and cooled water is discharged.

This requires:

• Supply pipeline
  – supplies hot coolant to the consumer;
• Return pipeline
  - performs the work of removing the cooled coolant and returning it to the district boiler room.

Several houses, and in some cases each one if the houses are large, are equipped with thermal chambers. They distribute coolant between houses, and also install shut-off valves that serve to cut off pipelines. Drainage devices can also be installed in the chambers, which are used to empty pipes, for example, for repair work. Further, the process depends on the temperature of the coolant.

In our country there are several main modes of operation of district boiler houses:

• Supply 150 and return 70 degrees Celsius;
• Respectively 130 and 70;
• 95 and 70.

The choice of mode depends on the latitude of residence. So, for example, for Moscow a 130/70 schedule will be sufficient, but for Irkutsk a 150/70 schedule will be needed. The names of these modes have the numbers of the maximum load of the pipelines. But depending on the air temperature outside the window, the boiler room can operate at temperatures of 70/54.

This is done to prevent overheating in the rooms and to make them comfortable to stay in. This adjustment is performed at the boiler room and is a representative of the central type of adjustment. An interesting fact is that in European countries a different type of regulation is performed - local. That is, adjustment takes place at the heat supply facility itself.

In this case, heating networks and boiler houses operate at maximum capacity. It is worth saying that the highest performance of boiler units is achieved precisely at maximum loads. comes to the consumer and is locally regulated by special mechanisms.

These mechanisms consist of:

• Outdoor and indoor temperature sensors;
• Servo drive;
• Actuator with valve.

Such systems are equipped with individual devices for metering thermal energy, thereby achieving great savings in monetary resources. Compared to elevators, such systems are less reliable and durable.

So, if the coolant has a temperature of no more than 95 degrees, then the main task is the high-quality physical distribution of heat throughout the system. To achieve these goals, manifolds and balancing valves are used.

But in the case when the temperature is above 95 degrees, it needs to be reduced a little. This is what elevators do in the heating system; they add chilled water from the return line to the supply pipeline.

Important. The process of adjusting the elevator unit is the simplest and cheapest mechanism; the main thing is to correctly calculate the heating elevator.

Features and Specifications

As we have already figured out, the elevator of the heating system is responsible for cooling the superheated water to a given value. This prepared water then enters.

This element improves the quality of operation of the entire building system and, when properly installed and selected, performs two functions:

• Mixing;
• Circulation.

Advantages of the elevator heating system:

• Simplicity of design;
• High efficiency;
• No electrical connection required.

Flaws:

• We need accurate and high-quality calculation and selection of a heating elevator;
• There is no way to regulate the outlet temperature;
• It is necessary to maintain a pressure difference between supply and return of around 0.8-2 bar.

Nowadays, such elements have become widespread in heating networks. This is due to their advantages, such as resistance to changes in hydraulic and temperature conditions. In addition, they do not require constant human presence.

Important. Calculation, selection and configuration of elevators should not be done with your own hands; this matter is best left to specialists, since a selection error can lead to big problems.

Design

The elevator consists of:

• Vacuum chambers;
• Nozzles;
• Jet elevator.

Among heating engineers there is a concept called piping an elevator unit. It consists of installing the necessary shut-off valves, pressure gauges and thermometers. All this is assembled and is a unit.

Important! Today, manufacturers sell elevators that, thanks to an electric drive, can adjust the nozzle. At the same time, it is possible to adjust the coolant flow automatically. But it is also worth noting that such equipment does not yet have a high degree of reliability.

How does an elevator work?

In simple terms, an elevator in a heating system is a water pump that does not require external energy. 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 times. 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.

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.

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Electric elevators help solve the problem of quality regulation. 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 – actuator housing 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.

The adjustable heating elevator, which appeared relatively recently, allows for the modernization of heating points without a radical replacement of equipment. Considering how many other similar units operate in the CIS, such units are becoming increasingly relevant.

How does a heating unit with an elevator mixing unit work?

Elevator mixing units are installed in heating points of buildings that are connected to a heating network operating in a mode with high-quality regulation on “superheated” water.

Qualitative regulation involves changing the temperature of the water entering the heating system depending on the temperature of the outside air, with a constant flow of water circulating in it.

"Overheated"

water is considered if it comes from the heating network at a temperature higher than that required for supply to the heating system.

For example, a heating network can operate on a schedule of 150/70, 130/70 or 110/70, and a heating system is designed on a schedule of 95/70. The temperature graph 150/70 assumes that at the design temperature of the outside air (for Kiev this is -22°C), the temperature at the entrance of the heating networks into the house should be equal to 150°C, and it should go into the heating network at a temperature of 70°C, while This water should enter a house designed for a 95/70 schedule at a temperature of 95°C.

The elevator unit mixes the water flow from the heating network supply with a temperature of 150°C and the water flow leaving the heating system with a temperature of 70°C; as a result of mixing, a flow with a temperature of 95°C is obtained at the elevator outlet, which is supplied to the heating system.

How does mixing occur?

In the mixing chamber of the elevator unit there is a “nozzle/cone” confuser that accelerates the flow of superheated water. As the flow speed increases, the pressure in it decreases (this property is described by Bernoulli's law) so much that it becomes slightly lower than the pressure in the return pipeline. The pressure difference between the mixing chamber and the return pipeline leads to the flow of coolant through the “elevator boot” jumper from the return to the supply.

In the mixing chamber, a mixture of two streams is formed with the required temperature, but the pressure is lower than the pressure of the return pipeline. The mixture enters the elevator diffuser, in which the flow rate decreases and the pressure increases above the return pipeline pressure. The pressure increase is no more than 1.5 m.w.c., which imposes restrictions on elevator units for use in heating systems with high hydraulic resistance.

1 Cheap and easy

2 Maintenance free

3 Does not depend on the electrical network

Disadvantages of elevator mixing units

1 Not compatible with automatic regulators, therefore their joint installation is prohibited by law.

2 Creates an available pressure at the input to the heating system of no more than 1.5 m of water column, which excludes the installation of elevator heating units in buildings whose heating systems are equipped with radiator thermostatic valves.

3 The elevator unit has a constant mixing coefficient, which does not allow supplying coolant of the required temperature to the heating system if the heating network is underheated.

4 Too high sensitivity to the available pressure at the input of the heating network. A decrease in the available pressure relative to the calculated value leads to a decrease in the volumetric flow rate of water circulating in the heating system, which in turn leads to an imbalance of the system and stopping of distant risers/branches.

5 For the elevator to operate, the pressure difference between the supply and return pipelines must exceed 15 m.w.c.

Where are heating points with elevator units installed?

Almost all heating systems put into operation before 2000 are equipped with heating points with elevator units.

Where can elevator ITPs be used?

Currently, for all designed and reconstructed residential and administrative buildings, the use of automatic control at the heating point is mandatory. The use of elevator units in conjunction with automatic regulators is prohibited by regulation.

Elevator units can be installed only in facilities where there is no need for automatic control of the heating system, the available pressure (pressure difference between the supply and return pipelines) at the inlet is stable and exceeds 15 m.w.st., for the operation of the connected heating system, the pressure difference between the supply and return is sufficient return to 1.5 m.water column, and the heating system operates with a constant flow rate and is not equipped with automatic regulators.

Main disadvantages

Despite the fact that the elevator unit has many advantages, it also has one significant drawback. It’s just that the elevator circuit does not provide for the possibility of adjusting the temperature of the outgoing coolant. If the return water temperature indicates that it is very hot, you will need to reduce it. This problem can only be solved by reducing the size of the nozzle, but this cannot always be done due to the design features of the equipment.

In some cases, the heating unit is equipped with an electric drive, thanks to which the size of the nozzle can be adjusted. It moves the main structural element - the throttle cone needle. This needle moves a certain distance into the hole inside the nozzle. The depth of movement makes it possible to change the diameter of the nozzle and thereby regulate the temperature of the coolant.

Both a manual drive in the form of a handle and a remotely controlled electric motor can be installed on the shaft.

It must be said that the installation of this temperature regulator makes it possible to improve the overall heating system with a thermal unit without significant material costs.

Description

Elevators are a complex of structures, which may include: a working building, silo buildings, devices for loading and unloading grain, grain dryers, etc. Elevators with a full or reduced complex of structures are built on the territories of existing enterprises. The construction of silo buildings attached to the working buildings of existing elevators is widespread. Reinforced concrete silos (containers) with a capacity of 11.2 to 48.0 thousand tons are assembled from two types of silos: square prefabricated structures measuring 3x3 along the axes of the walls and round monolithic ones with a diameter of 6 and 9 meters or prefabricated silos with a diameter of 6 meters, the height is usually 30 meters . Square silos are arranged in widths of six, eight and twelve rows, and round ones - in three, four and six rows. Metal silos with a capacity of 2.55 and 3.0 thousand tons, a diameter of 18 meters, a height of 11.9 and 15 meters, are arranged sequentially in one row (2...4 silos each). The silos are interconnected with the working building, where the main technological and transport equipment is located. Grain from receiving bins is lifted by conveyors or vertical lifts (elevators) to the top of the working building, weighed, cleaned of impurities, dried in grain dryers and sent along the upper conveyor to over-silo conveyors, which dump it into silos. The grain is unloaded onto the lower conveyors (they are installed in the sub-silo floor) through holes with funnels in the bottoms of the silos. Some silos are equipped with installations for grain disinfection and active ventilation. The grain temperature is measured using thermal pendants installed at different levels.

Now, as a rule, the elevator has points for auto reception, railway reception, auto and railway loading. Previously, there were often cases when the direct supply of grain to the elevator itself was carried out using manual labor. In this case, people throw grain with shovels from the surface of the ground or from the back of a car onto a receiving conveyor, which, like a snowblower, lifts the grain and pours it into the route networks of the elevator. The first silo elevator was built in the USA (Duluth) in 1845, in Russia (Nizhny Novgorod) - in 1887.

SCAFCO grain elevator for 120,000 tons of storage in Kazakhstan. 2015

Depending on their purpose, elevators are divided into:

• grain receiving or procurement (receive grain from farms, clean it of impurities, dry it and ship it to the consumer; capacity 15-100 thousand tons);
• production (built at mills, cereal, feed mills, starch factories, etc.; 10-150 thousand tons);
• basic (designed for long-term storage of grain received from railway transport and loaded into railway cars; 100-150 thousand tons);
• transshipment and port (built in places where grain is transshipped from one type of transport to another - at large railway stations, in seaports; 50-100 thousand tons).

Rectangular elevators with silos of larger diameter (up to 30 m) and height (up to 60 m) made of metal (steel, aluminum) are also common abroad. In Russia, working elevator towers with a height of 53-60 meters, and silo buildings with a height of 43 meters are common.

Switchgears

The elevator unit with all its piping can be thought of as a pressure circulation pump, which supplies coolant to the heating system under a certain pressure.

If the facility has several floors and consumers, then the most correct solution is to distribute the total coolant flow to each consumer.

To solve such problems, a comb is designed for the heating system, which has another name - a collector. This device can be represented as a container. The coolant flows into the container from the elevator outlet, which then flows out through several outlets, with the same pressure.

Consequently, the distribution comb of the heating system allows the shutdown, adjustment, and repair of individual consumers of the facility without stopping the operation of the heating circuit. The presence of a collector eliminates the mutual influence of the heating system branches. In this case, the pressure in the heating radiators corresponds to the pressure at the elevator outlet.

general description

Before understanding the diagram of the elevator heating unit, it must be said that by its design the elevator is a kind of circulation pump, which is located in the heating system along with pressure meters and shut-off valves.
Thermal elevator units perform a number of functions in their operation. To begin with, this electronic device distributes pressure in the heating system so that water is delivered to consumers into the heating radiators at a certain pressure and temperature. During circulation through pipes from the boiler room to multi-storey buildings, the volume of coolant in the circuit almost doubles. This can only happen if there is a supply of water in a separate sealed container.

Most often, a coolant is supplied from the boiler room at a temperature of about 110-160℃. For domestic needs, in terms of safety, these high temperatures are unacceptable. The maximum temperature of the coolant in the circuit cannot be more than 90℃.

From this video we will learn the principle of operation of the elevator heating unit:

It is also noteworthy that SNiP currently indicates the coolant temperature standard in the range of 65℃. But to save resources, there is active discussion about reducing this standard to 55℃. Taking into account the opinion of experts, the consumer will not feel a significant difference, and for disinfection, the thermal fluid will need to be heated to 75℃ once a day. However, these changes to SNiP have not yet been adopted, since there is no precise opinion regarding the effectiveness and appropriateness of this decision.

This device allows you to prevent the following consequences

:

• if the wiring is made of propylene or plastic pipes, then it is not designed to supply hot thermal fluid;
• not all heating pipes are designed for prolonged exposure to elevated temperatures under high pressure - these conditions will lead to their rapid failure;
• Very hot heating radiators can cause burns if not handled carefully.

Three way valve

If it is necessary to divide the coolant flow between two consumers, a three-way heating valve is used, which can operate in two modes:

• constant mode;
• variable hydraulic mode.

A three-way valve is installed in those places in the heating circuit where it may be necessary to divide or completely shut off the flow of water. The tap material is steel, cast iron or brass. Inside the faucet there is a shut-off device, which can be ball, cylindrical or conical. The tap resembles a tee and, depending on the connection, a three-way valve on a heating system can work as a mixer. Mixing proportions can be varied within wide limits.

The ball valve is mainly used for:

1. adjusting the temperature of heated floors;
2. adjusting battery temperature;
3. distribution of coolant in two directions.

There are two types of three-way valves - shut-off and control valves. In principle, they are almost equivalent, but with three-way shut-off valves it is more difficult to regulate the temperature smoothly.

Basic rules for installing a warm water floor circuit

A water-heated floor heats the surface of the finishing coating indirectly through a concrete screed, the thickness of which is 5 cm. If installed correctly, under this screed there are the following elements:

• water and steam protection made of polyethylene film;
• rough concrete screed 15 cm thick;
• heat-insulating layer made of foil insulation.

In addition, another layer of steam and water protection is laid on top of the heating screed.

The water heated floor register is laid out at a distance of 50 cm between the knees and no closer than 20 cm to the walls. One end of the pipe is removed from the boiler through the mixing unit, the second is the return line and is connected to it in front of the boiler.

The screed device involves the use of pipes without joints, which is only possible when using plastic or metal-plastic pipes. The joint is the weak point of the pipeline, and if repairs are necessary, the screed will have to be dismantled.

Principle of operation

To understand how the node works, it is necessary to give an example. To do this, we will take a three-story house, since the elevator unit is used specifically in multi-story buildings. The main part of the equipment that belongs to this system is located in the basement. The diagram below will help us better understand the work. We see two pipelines:

1. The server.
2. Back.

Diagram of a heating unit for a multi-storey building.
Now you need to find on the diagram the thermal chamber through which water is sent to the basement. You can also notice shut-off valves, which must be installed at the entrance. The choice of fittings depends on the type of system. For the standard design, valves are used. But if we are talking about a complex system in a multi-story building, then the experts recommend using steel ball valves.

When connecting a thermal elevator unit, you must adhere to the standards. First of all, this concerns temperature conditions in boiler rooms. During operation, the following indicators are allowed:

When the liquid temperature is in the range of 70-95°C, it begins to be evenly distributed throughout the system due to the operation of the collector. If the temperature exceeds 95°C, the elevator unit begins to work to lower it, since hot water can damage equipment in the house, as well as shut-off valves. This is why this type of construction is used in multi-storey buildings - it controls the temperature automatically.

Connection diagrams

The elevator unit can be used in systems with various specific features - single-pipe, autonomous or other heat supply lines. The principles of coolant supply and flow parameters do not always allow for a constant and stable output result. To organize normal heat supply to apartments or adjust the flow parameters coming from the main network, various connection schemes for elevator units are used. All of them require additional equipment, sometimes in quite large quantities, but the result achieved as a result of this compensates for the costs incurred. Let's look at the existing connection diagrams:

With water flow regulator

Water consumption is the main factor that makes it possible to adjust the heating mode of the premises. Changes in flow cause temperature fluctuations in living rooms, which is unacceptable. The issue is resolved by installing a regulator in front of the mixing unit, which ensures constant water flow and stabilizes the thermal regime.

Diagram of an elevator mixing unit with a flow regulator: 1 - supply line of the heating network; 2 - return line of the heating network; 3 - elevator; 4 - flow regulator; 5 - local heating system

This solution becomes especially important in single-pipe systems, where there is a load in the form of hot water supply, which destabilizes the flow of hot water and creates significant fluctuations during active water withdrawal (morning and evening hours, holidays and weekends). At the same time, this scheme is not able to correct the situation when the temperature of the coolant in the main line changes, which is its drawback, although not too significant. A drop in coolant temperature in the supply pipelines means an accident at a thermal power plant or other heating point, and this rarely happens.

With regulating nozzle

The connection diagram of the elevator unit with the ability to adjust the nozzle capacity allows you to quickly respond to changes in coolant parameters in the main line.

Diagram of an elevator unit with a regulating needle: 1 - supply line of the heating network; 2 - return line of the heating network; 3 - elevator; 5 - local heating system; 6 - regulator with a needle pushed into the elevator nozzle

At the same time, manual adjustment is ineffective, since for this you need to constantly approach the elevator, which is usually located in the basement. The greatest efficiency of a system with an adjustable nozzle is achieved with complete automation of the process, using temperature and pressure sensors that send a signal to the elevator servo drive. This scheme allows you to gain additional opportunities when setting the operating mode, but the need for it does not always arise, but only in overloaded or unstable systems with possible fluctuations in coolant temperature.

Diagram of an elevator unit using temperature and pressure sensors that send a signal to the elevator servo drive

The disadvantages of such schemes include the need to initially ensure high pressure in the system, since adjustment is possible only within the limits of the flow parameters in the line. In addition, loads on the mechanics, in particular on the nozzle and needle, create the need for constant monitoring and timely replacement of failed elements.

With control pump

Such schemes are used in the absence of sufficient pressure in the supply pipelines for the operation of the elevator.

Diagram of an elevator unit with a correction pump: 1 - supply line of the heating network; 2 - return line of the heating network; 3 - elevator; 4 - flow regulator; 5 - local heating system; 7 — temperature controller; 8 - mixing pump

An increase in pressure makes it possible to use an elevator unit in the autonomous heating networks of a private house and allows for circulation of the coolant when the pressure in the main disappears. The pump is installed in front of the elevator or on the jumper between the forward and return pipelines before entering the elevator. To ensure normal operation, a temperature controller must be used in addition to the pump, and a power supply must be connected.

Parsing the circuit

As you understand, the unit consists of filters, an elevator, instrumentation and fittings. If you plan to install this system yourself, then it’s worth understanding the diagram. A suitable example would be a high-rise building, in the basement of which there is always an elevator unit.

In the diagram, the system elements are marked with numbers:

1, 2 – these numbers indicate the supply and return pipelines that are installed in the heating plant.

3.4 – supply and return pipelines installed in the heating system of the building (in our case, this is a multi-storey building).

6 – this number indicates coarse filters, which are also known as mud filters.

The standard composition of this heating system includes control devices, mud traps, elevators and valves. Depending on the design and purpose, additional elements may be added to the unit.

Interesting! Today, in multi-storey and apartment buildings you can find elevator units that are equipped with an electric drive. This modernization is needed in order to adjust the nozzle diameter. Due to the electric drive, the thermal fluid can be adjusted.

It is worth saying that utilities become more expensive every year, and this also applies to private homes. In this regard, system manufacturers provide them with devices aimed at saving energy. For example, now the circuit may contain flow and pressure regulators, circulation pumps, pipe protection and water purification elements, as well as automation aimed at maintaining a comfortable mode.

Also in modern systems a thermal energy metering unit can be installed. From the name you can understand that it is responsible for accounting for heat consumption in the house. If this device is missing, the savings will not be visible. Most owners of private houses and apartments strive to install meters for electricity and water, because they have to pay significantly less.

Purpose and principle of operation of the elevator in the heating system

Thermal stations or large boiler houses are capable of providing hot coolant to large areas. In this regard, the length of heating networks can reach tens of kilometers, which causes significant heat losses in the mains. Therefore, the initial temperature of the coolant from stations and boiler houses is selected taking into account these heat losses. Regulatory documents establish several modes of temperature parameters for the supply and return of heating networks, the main ones being 150 / 70, 130 / 70, 95 / 70.

Since, for safety reasons and to reduce losses, the temperature in the radiator heat exchangers of buildings should not exceed 95 °C, many consumers of thermal energy in buildings located at a short distance from heating plants have to solve the problem of partial cooling of water heated to temperatures of about 150 or 130 °C.

This can only be achieved by mixing the incoming and cooled return flow in a tee assembly. However, if mixing is carried out in a conventional tee, there will be no water flow in it and, accordingly, the movement of the coolant through the pipeline will stop. Therefore, a narrow nozzle is made in the mixing unit in the path of the feed flow. This leads to an increase in the speed of the water flow and, accordingly, a decrease in its pressure in the nozzle area, which is directly related to the diameter of the pipeline. As a result, the turbulent flow carries along water masses from the return, thus ensuring the movement of the coolant along the circuit.

A tee with an internal narrowed nozzle is the type of fitting that is called an elevator unit.

It should be noted that the elevator simultaneously performs the functions of a mixer and a circulation pump that pushes the coolant through the heating circuit. To the listed works you can add its functioning as a pressure reducer and a thermostat that reduces the temperature to the required parameters.

Rice. 2 Elevator calculation formulas

Unit characteristics and operating features

From the diagrams you can understand that the elevator in the system is needed to cool the overheated coolant. Some designs have an elevator, which can also heat water. This heating system is especially relevant in cold regions. The elevator in this system starts only when the cooled liquid is mixed with hot water coming from the supply pipe.

Scheme. The number “1” indicates the supply line of the heating network. 2 is the return line of the network. The number “3” indicates the elevator, 4—the flow regulator, and 5—the local heating system.

Don't miss: Diagrams of heating systems with one boiler

From this diagram you can understand that the unit significantly increases the efficiency of the entire heating system in the house. It works simultaneously as a circulation pump and mixer. As for the cost, the unit will be quite cheap, especially the option that operates without electricity.

But any system also has disadvantages, the collector unit is no exception:

• Separate calculations are required for each element of the elevator.
• Compression drops should not exceed 0.8-2 bar.
• Lack of ability to control high temperature.

Diagrams of thermal units

If we talk about the schemes of heating points, it should be noted that the most common types are the following:

Thermal unit is a circuit with a parallel single-stage hot water connection. This scheme is the most common and simple. In this case, the hot water supply is connected in parallel to the same network as the heating system of the building. The coolant is supplied to the heater from the external network, then the cooled liquid flows in the reverse order directly into the heat pipe. The main disadvantage of such a system, compared to other types, is the high consumption of network water, which is used to organize hot water supply.

Diagram of a heating point with a sequential two-stage connection of hot water. This scheme can be divided into two stages. The first stage is responsible for the return pipeline of the heating system, the second - for the supply pipeline. The main advantage of thermal units connected according to this scheme is the absence of a special supply of network water, which significantly reduces its consumption. As for the disadvantages, this is the need to install an automatic control system to configure and adjust the heat distribution. This connection is recommended to be used if the ratio of the maximum heat consumption for heating and hot water supply is in the range from 0.2 to 1.

Thermal unit is a circuit with a mixed two-stage connection of a hot water heater. This is the most universal and flexible connection scheme. It can be used not only for normal temperature schedules, but also for elevated ones. The main distinguishing feature is the fact that the heat exchanger is connected to the supply pipeline not in parallel, but in series. The further principle of the structure is similar to the second scheme of the heating point. Thermal units connected according to the third scheme require additional consumption of network water for the heating element.

Possible problems

As a rule, most problems in the elevator unit arise for the following reasons:

• clogging in equipment;
• changes in the diameter of the nozzle as a result of equipment operation - an increase in the cross-section makes it more difficult to regulate the temperature;
• blockages in mud traps;
• failure of shut-off valves;
• regulator failures.

In most cases, finding out the cause of problems is quite simple, since they are immediately reflected in the temperature of the water in the circuit. If the temperature differences and deviations from the standards are insignificant, there is probably a gap or the nozzle cross-section has increased slightly.

A difference in temperature readings of more than 5 ℃ indicates the presence of a problem that can only be solved by specialists after diagnostics.

If, as a result of oxidation from constant contact with water or involuntary drilling, the cross-section of the nozzle increases, the balance of the entire system is disrupted. Such a flaw must be corrected as quickly as possible.

It is worth noting that in order to save money and use heating more efficiently, electricity meters can be installed at heating units. And hot water and heat meters make it possible to further reduce utility bills.

Results

In this article we found out what an elevator is in a heating system, what it consists of and how it works. As it turned out, such equipment is widespread due to its undeniable advantages. There is no reason for utility companies to abandon them.

There are alternatives for this equipment, but they are distinguished by their high cost, lower reliability and energy efficiency, because they require electricity and periodic repairs to operate.

For heating systems in residential premises, there is a standard coolant temperature. In accordance with the established standard, 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 by the correct choice of 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.

Areas of application and purpose

Having understood the heating unit diagram, you can proceed directly to installation work. As you know, such installations are often used in multi-apartment premises that are connected to a common communal heating system.

Thermal units are designed for such tasks:

1. Checking and changing the operating properties of the coolant and thermal potential.
2. Monitoring the current state of heating systems.
3. Monitoring and recording the main indicators of the coolant - current temperature, pressure and volume.
4. Carrying out cash calculations and drawing up an optimal energy expenditure plan.

When installing a heating system in a room, you need to understand that central heating requires certain costs. If we are talking about an apartment building, then all costs are divided among the residents. But sometimes they are unjustified due to the dishonest attitude of management companies and incorrect installation of system parts.

And in order to prevent significant financial damage, it is important to install in advance a highly efficient heating unit in a private home, which will automatically regulate any changes and select the optimal coolant temperature ratio. Only competent testing of equipment and proper maintenance will allow you to set up an effective heating system that will last for many years without failures.

A little about the disadvantages

Despite the fact that the thermal unit has many advantages, it also has one significant drawback. The fact is that it is impossible to regulate the temperature of the exiting coolant using an elevator. If measuring the return water temperature shows that it is too hot, it will need to be lowered. This task can be accomplished only by reducing the diameter of the nozzle, however, this is not always possible due to design features.

Sometimes the thermal unit is equipped with an electric drive, with the help of which it is possible to adjust the diameter of the nozzle. It sets in motion the main part of the design - a cone-shaped throttle needle. This needle moves a specified distance into the hole along the internal cross-section of the nozzle. The depth of movement allows you to change the diameter of the nozzle and thereby control the temperature of the coolant.

Both a manual drive in the form of a handle and an electric remote-controlled motor can be installed on the shaft.

It is worth noting that the installation of such a unique temperature regulator allows you to modernize the overall heating system with a thermal unit without significant financial investments.

Installation features and testing

Installation of the elevator unit

It is worth immediately noting that installation and testing of the operation of the elevator unit and heating system is the prerogative of representatives of the service company. Residents of the house are strictly prohibited from doing this. However, knowledge of the layout of the elevator units of the central heating system is recommended.

During design and installation, the characteristics of the incoming coolant are taken into account. The branching of the network in the house, the number of heating devices and the operating temperature are also taken into account. Any automatic elevator unit for heating consists of two parts.

• Adjusting the intensity of the flow of incoming hot water, as well as measuring its technical indicators - temperature and pressure;
• Directly the mixing unit itself.

The main characteristic is the mixing coefficient. This is the ratio of the volumes of hot and cold water. This parameter is the result of precise calculations. It cannot be a constant, since it depends on external factors. The installation must be carried out strictly according to the diagram of the elevator unit of the heating system. After this, fine tuning is done. To reduce errors, a maximum load is recommended. This way the water temperature in the return pipe will be minimal. This is a prerequisite for precise control of the automatic valve.

After a certain period of time, scheduled checks of the operation of the elevator unit and the heating system as a whole are necessary. The exact procedure depends on the specific scheme. However, you can draw up a general plan that includes the following mandatory procedures:

• Checking the integrity of pipes, shut-off valves and devices, as well as compliance of their parameters with passport data;
• Adjustment of temperature and pressure sensors;
• Determination of pressure loss during coolant passage through the nozzle;
• Calculation of the displacement coefficient. Even for the most accurate heating scheme for an elevator unit, equipment and pipelines wear out over time. This amendment must be taken into account when setting up.

After this work has been completed, the automatic central heating elevator unit must be sealed to prevent tampering.

You cannot use homemade schemes of elevator units for central heating systems. They often do not take into account the most important characteristics, which can not only reduce operational efficiency, but also cause an emergency.

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:

1. Checking the integrity of pipes;
2. Verification of instruments, adjustment of pressure sensors and thermometers;
3. Calculation of pressure loss when water passes through the nozzle;
4. Calculation of the displacement coefficient. This value must be taken into account when setting up the system, since even a perfectly mounted and installed unit and pipeline wear out over time.

After a routine inspection, the system is sealed to secure its settings and prevent unauthorized changes.

Premises requirements

In the vast majority of cases, mixing units are installed in the basement of the building. To perform its functions, it is necessary to take into account the characteristics of the room - seasonal changes in temperature and humidity.

There are a number of requirements for these indicators, the fulfillment of which is mandatory. This especially applies to elevator units of the central heating system with installed automatic servos:

• The room temperature should not fall below 0°C;
• To prevent the appearance of condensation on the surface of the pipes, an exhaust ventilation system is installed;
• A separate switchboard must be installed for electrical appliances. It is recommended to provide an autonomous power supply in case of an emergency power outage.

However, in fact, it is rare to see adherence to these rules. As a result, even for the most effective drawing of an elevator unit, its practical implementation may differ significantly. That is why alternative schemes for mixing coolant flows have appeared.

Some new apartment buildings connected to central heating do not have a heating circuit with an elevator unit. To install it, you need to contact the management company.

How does an elevator work?

Studying the diagram of the elevator unit of the heating system, namely what it is and how it functions, one cannot help but note the similarity of the finished design with water pumps. At the same time, operation does not require obtaining energy from other systems, and reliability can be observed in specific situations.

The main part of the device from the outside is similar to a hydraulic tee installed on the return line. Through a simple tee, the coolant would easily flow into the return, bypassing the radiators. Such a heating unit design would be inappropriate.

In the usual diagram of the elevator unit of the heating system there are the following details:

• A preliminary chamber and a supply pipe with a nozzle of a certain cross-section installed at the end. Coolant from the return branch is supplied through it.
• A diffuser is built into the outlet. It is designed to transfer water to consumers.

At the moment, you can find units where the nozzle cross-section is adjusted by an electric drive. Thanks to this, you can automatically adjust the acceptable coolant temperature.

The selection of a heating unit circuit with an electric drive is made on the basis that it is possible to change the coolant mixing coefficient within 2-5 units. This cannot be achieved in elevators, in which the nozzle cross-section cannot be changed. It turns out that systems with an adjustable nozzle make it possible to significantly reduce heating costs, which is very important in houses with central meters.

What is an elevator?

In simple terms, an elevator is a special device related to heating equipment and performs the function of an injection or water-jet pump. No more, no less.

Its main task is to increase the pressure inside the heating system. That is, increase the pumping of coolant through the network, which will lead to an increase in its volume. To make it clearer, let's give a simple example. 5-6 cubic meters of water are taken from the supply water supply as a coolant, and 12-13 cubic meters enter the system where the apartments of the house are located.

How is this possible? And what causes the increase in coolant volume? This phenomenon is based on certain laws of physics. Let's start with the fact that if an elevator is installed in the heating system, it means that this system is connected to central heating networks through which hot water moves under pressure from a large boiler house or thermal power plant.

So the temperature of the water inside the pipeline, especially in extreme cold, reaches +150 C. But how can this be? After all, the boiling point of water is +100 C. This is where one of the laws of physics comes into force. At this temperature, water boils if it is in an open container where there is no pressure. But in the pipeline, water moves under pressure, which is created by the operation of the supply pumps. That's why it doesn't boil.

• Firstly, cast iron does not like large temperature changes. And if cast iron radiators are installed in apartments, they may fail. It's good if they just leak. But they can break, because under the influence of high temperatures, cast iron becomes brittle, like glass.
• Secondly, at this temperature of metal heating elements it will not be difficult to get burned.
• Thirdly, plastic pipes are now often used for piping heating devices. And the maximum that they can withstand is a temperature of +90 C (besides, with such figures, manufacturers guarantee 1 year of operation). This means they will simply melt.

Therefore, the coolant must be cooled. This is where an elevator is needed.

Possible faults

A common malfunction is mechanical failure of the elevator. This may occur due to an increase in the diameter of the nozzle, defects in shut-off valves, or clogged mud traps. It is quite simple to understand that the elevator is out of order - there are noticeable differences in the temperature of the coolant after and before passing through the elevator. If the temperature is low, the device is simply clogged. When there are large differences, elevator repair is required. In any case, when a malfunction occurs, diagnostics are required.

The elevator nozzle gets clogged quite often, especially in places where the water contains many additives. This element can be dismantled and cleaned. If the nozzle diameter has increased, adjustment or complete replacement of this element is necessary.

Other malfunctions include overheating of devices, leaks and other defects inherent in pipelines. As for the mud tank, the degree of its clogging can be determined by the readings of the pressure gauges. If the pressure increases after the mud filter, then the element needs to be checked.

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 carried out manually (by rotating the valve) or automatically (adjustment occurs due to the movement of the rod installed inside the nozzle, the 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 install elevator heating units. But with proper installation of high-quality equipment, even a system with automatic control of nozzle capacity pays for itself within 3-5 years (due to savings on heating fees).

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, and also due to the formation of blockages.

Noise

The heating elevator may 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 corrected 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 of an apartment building. By regulating the volume of coolant in two flows, the optimal temperature for the home heating system is achieved.

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 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 coolant temperature 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 the house heating system. In most cases this is simply not possible.

More often we are dealing with a dual-circuit system, the so-called independent connection circuit.

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.

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 are not destroyed by the pressure of 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.