Elevator unit of the heating system

heating elevator To correctly understand the importance of the elevator node, it is probably necessary to first briefly consider how the workscentral heating systems.

The thermal energy source is the CHP or boiler houses where the heating medium is heated to the desired temperature by using a particular type of fuel( coal, oil products, natural gas and , .) From there, the heat transfer medium is pumped throughpipes to the points of consumption.

CHP or large boiler house is calculated by on the providing heat to the of a certain district, sometimes - with a very considerable territory. Pipeline systems are very long and branched .How to minimize heat losses and evenly distribute it according to to the customers, so that, for example, the most remote from the CHP building did not experience the deficiency in it ?This is achieved by careful thermal insulation of the thermal mains and by maintaining in them a certain thermal regime.

In practice, several theoretically calculated and practically tested temperature operating modes of boiler houses are used that provide heat transfer to significant distances without significant losses and maximum efficiency and economy of boiler equipment operation. So, for example, apply modes 150/70, 130/70, 95/70( water temperature in the supply line / temperature in the return ).The choice of a particular mode depends on the climatic zone of the region and on the specific level of the current winter air temperature.

1 - Boiler room or CHP.

2 - Consumers of thermal energy.

3 - High-temperature coolant supply main.

4 - The backbone of the backbone.

5 and 6 - Offshoots from highways to buildings - consumers.

7 - in-house thermal distribution centers.

From the supply mains and " returns" there are branches to each building, connected to the to this network. But here at once there are questions.

• First, different objects require different amounts of heat - do not compare, for example, a huge residential high-rise and a small low-rise building.
• Secondly, the water temperature in the mains does not correspond to the permissible standards for supply directly to heat exchangers. As can be seen from the of the modes, the temperature very often even exceeds the boiling point, and the water is maintained in the liquid aggregate state only for the account of the high pressure and hermetic system.

The use of such critical temperatures in heated rooms is unacceptable. And it's not just about the excess of heat energy intake - it's extremely dangerous. Any touch to the batteries heated up to this level will cause a severe burn of the tissues, and in the case of even a slight depressurization, the coolant instantly turns into hot steam, which can lead to very serious consequences.

The right choice of radiators is extremely important!

Not all heating radiators are the same. It's not only and not so much in the material of manufacture and appearance. They can significantly differ in their performance characteristics, adaptation to a particular heating system.

How to properly approach the selection of heating radiators - in a special article of our portal.

Thus, it is necessary to reduce the temperature and pressure to the of the calculated operating levels at the local thermal house of the house, while ensuring the required heat selection sufficient for the heating needs of a particular building. This role is performed by special heat engineering equipment. As already mentioned, these can be modern automated systems, but very often the gives the a preference for the proven elevator system scheme.

can look like. If you look at the thermal distribution board from where is located( most often they are located in the basement, at the point of entry of the main heating networks), you can see the node in which the jumper between the pipes is clearly visibleand " returns ".It is here that the elevator itself stands, the device and the principle of operation will be described below.

elevator

The elevator itself is a cast iron or steel structure, the is equipped with three flanges for inserting into the system .

Let's look at its structure inside.

jet elevator. Overheated water from the heat main enters the inlet branch of the elevator( item 1).Moving under pressure forward , it passes through a narrow nozzle( pos.2).A sharp increase in the flow velocity at the nozzle outlet leads to the injection effect of the - in the receiving chamber( item 3) , the is created as a vacuum zone. In this area of ​​reduced pressure, the laws of thermodynamics and hydraulics literally draw in water from the branch pipe( item 4), of the connected to the pipe " return".As a result, mixing of hot and cooled flows takes place in the mixing neck of the elevator( item 5), the water receives the necessary temperature for the internal network, the pressure drops to a level safe for the heat exchangers, and then the coolant flows through the diffuser( item 6) into the systeminternal wiring.

In addition to reducing the temperature, the injector performs the role of a unique pump - it creates t t the water pressure that is required to provide with its circulation in the inter-house wiring, with the hydraulic resistance of the system being overcome.

As you can see, the system is extremely simple, but very effective, which makes its a wide application even in conditions of competition with modern high-tech equipment.

Certainly, the elevator needs certain strapping. The approximate scheme of the elevator unit is given by on the scheme:

elevator unit piping Hot water from the heating pipeline is supplied by the through the pipe( item 1), and returns to the on the pipe ( pos. 2).From the main pipes, the indoor system can be switched off by means of valves( key 3).All assembly of individual parts and devices is carried out using flange connections( item 4 ).

The adjusting equipment is very sensitive to the cleanliness of the coolant, therefore mud pumps( item 5), direct or "slanting" type, are mounted on the inlet and outlet of the system. In them I settle t t verdi insoluble inclusions and dirt that has fallen into the cavity of the pipes. Periodically, the mud collectors are cleared of collected precipitation.

On certain sections of the unit are installed instrumentation. These are pressure gauges( item 6), allowing to control the level of liquid pressure in the pipes. If the inlet pressure can reach 12 atmospheres, then it is much lower at the exit from the elevator unit, and depends on the number of heat exchange points in the and .

Thermal sensors - thermometers( item 7) are mandatory, which control the level of the coolant temperature: at the input of their central control panel - t and , the input to the internal system - t with , on the returns system and control panel- t for and t for .

Next, the elevator itself( item 8) is installed. The rules for its installation require a direct pipeline section of at least 250 mm. In one, it is connected via flange to flange to the supply pipe from the control panel, opposite - to the indoor distribution pipe( key 11).The lower flange connection is connected to the via a jumper( key 9) to the " " pipe( item 12).

For the provision of preventive or emergency repair works, valves( item 10) are provided, completely disconnecting the elevator unit from the indoor network. The diagrams are not shown, but in practice there are necessarily special elements for draining - draining water from the intra-house system if such necessity arises.

Undoubtedly, the scheme is given in a very simplified form, but it fully reflects the basic device of the elevator node. The wide arrows show the flow directions of the coolant with different temperature levels.

Undisputed advantages of using the elevator unit for temperature and pressure control of the coolant are:

• Simplicity of construction with trouble-free operation.
• Low cost of components and their installation.
• Complete non-volatility of such equipment.
• Using elevator units and devices heat allows to achieve savings in consumption of consumed heat carrier up to 30%.

There are, of course, very significant shortcomings:

• Each system requires an individual calculation of the to select the desired elevator.
• Required differential pressure at the inlet and outlet.
• Impossibility of precise smooth adjustments when the system parameters are changed.

The last drawback is quite specific, as in practice elevators are often used, in which the possibility of changing its performance is provided.

. For this purpose, a special needle - cone-shaped rod( item 2) is installed in the receiving chamber with a nozzle( key 1), which reduces the nozzle cross-section. This rod in the kinematics block( poses .3) through the rack gear transmission( poses . 4 - 5) is connected to the adjusting shaft( poses . 6).Rotating the shaft causes the cone to move in the cavity of the nozzle, increasing or decreasing the clearance for fluid passage. Accordingly, the operating parameters of the entire elevator assembly also change.

Depending on the automation level of the system, various types of controlled silos can be used.

So, the rotation transfer can be done manually - the responsible specialist monitors the readings of the instrumentation and corrects the operation of the system by orienting the on the on the worn near the flywheel( handle) scale.

servodr Alternatively, when the elevator unit is tied to an electronic control and monitoring system. The readings are taken in automatic mode, the control unit generates signals for transmission to servo drives through which the rotation is transmitted by the to the kinematic mechanism of the regulated elevator.

What you need to know about coolants?

In heating systems, especially in autonomous systems, not only water can be used as the heat medium.

What qualities should the coolant for the heating system have, and how to choose it correctly - in a special publication of the portal.

Calculation of and selection of elevator heating

As already mentioned, for each building requires certain amounts of thermal energy. This means that an defined elevator calculation is needed, based on the of the specified operating conditions of the system.

The initial data include:

1. Temperature values:

- at the input of their thermal center;

- in the " return" of the thermal central;

- the working value for an in-house heating system;

- in the return pipe of the system.

1. Total heat required for heating a particular house.
2. Parameters characterizing the features of the inter house heating distribution.

The procedure for calculating the elevator is established by a special document - the Code of Regulations for the Design of the Ministry of Construction of the Russian Federation, JV 41-101-95, dealing specifically with the design of heat points. In this guideline, the formulas for calculating the are given, but they are quite "heavy", and there is no particular need to give them in the article.

Those readers who are not very interested in the calculation questions can safely skip this section of the article. And for those who wish to calculate the elevator node independently, it can be recommended to spend 10 ÷ 15 minutes of time to create your own calculator based on the JV formulas, which allows you to conduct accurate calculations of literally for read seconds.

Create calculator for calculating

	Open a new file( book) in the Excel application of the Microsoft Office suite. In cell A1 type the text "Calculator for calculating the elevator of the heating system". Below, in the cell A2 we collect the "Initial data". Inscriptions can be "raised" by changing the fat content, font size or color.
	Below there are lines with cells for input of initial data, on the basis of which the elevator calculation will be carried out. Fill the text of the cell with A3 to A7 : A3 - "Coolant temperature, degrees C:" A4 - "in the heat pipe supply pipe" A5 - "in the return of the thermal center" A6 -"Necessary for an in-house heating system" A7 - "in the return of the heating system"
	For the sake of clarity, you can skip a line, and below, in the cell A9 we enter the text "The required amount of heat for the heating system, kW"
	We skip a line, andin cell A11 imprint "Resistance coefficient of the heating system at home, m". So that the text from the column is not found on the column In , where the data will be further entered, the A column can be expanded to the required width( indicated by an arrow).
	Data entry area, from A2-B2 to A11-B11 can be selected and filled with color. So it will differ from another area where the results of calculations will be given out.
	I skip one more line and enter into cell A13 "Calculation results:" You can select text in a different color.
	Next, the most important stage begins. In addition to entering text into the cells of the column, the column beside the cells in the next column contains the formulas according to which the calculations will be performed. The formulas should be transferred exactly, as will be indicated, without any unnecessary gaps. Important: The formula is entered in the Russian keyboard layout, except for the cell names - they are entered exclusively in the Latin layout. In order not to be mistaken with this, in the above examples of formulas the names of the cells will be highlighted in in bold type. So, in the cell A14 , type the text "Temperature difference of the thermal center, degrees C".in the cell B14 we enter the following expression =( B4 - B5 ) And to enter and control its correctness it is more convenient in the formula line( green arrow). Do not be confused by the fact that B14 immediately got a value( in this case, "0", a blue arrow), simply the program immediately fulfills the formula, leaning for the time being on empty input cells.
	Fill in the following line. In cell A15 - the text "Temperature difference of heating system, degrees C", and in cell B15 - formula =( B6 - B7 )
	Next line. In cell A16 - text: "Required capacity of the heating system, m3 / hr". Cell B16 should contain the following formula: =( 3600 * B9 ) /( 4,19 * 970 * B14 ) An error message appears, "divide by zero" - do not pay attention, it's just because, that the initial data are not entered.
	We go below. In cell A17 - the text: "Coefficient of mixing of the elevator". Next, in cell B17 - the formula: =( B4 - B6 ) /( B6 - B7 )
	Next, the cell A18 - "The minimum head of the coolant in front of the elevator, m." Formula in cell B18 : = 1,4 * B11 *( DEGREES( (1+ B17 ); 2)) Do not falter with the number of brackets - this is important.
	Next line. In the cell A19 the text: "Diameter of the neck of the elevator, mm." The formula in cell B18 is as follows: = 8,5 * DEGREE( (DEGREE( B16 ; 2) * DEGREE( 1+ B17 ; 2)) / B11 ; 0,25)
	And the lastline of calculations. In the cell A20 the text "Diameter of the nozzle of the elevator, mm" is entered. In cell B20 - formula: = 9,6 * DEGREE( DEGREE( B16 ; 2) / B18 ; 0,25)
	In fact, the calculator is ready. One can only slightly modernize it so that it is more convenient to work with, and there was no risk of accidentally deleting the formula. First, select the area from A13-B13 to A20-B20 , and fill it with another color. The fill button is indicated by an arrow.
	Now select the common area with A2-B2 for A20-B20 . In the "borders" drop-down menu ( shown by the arrow), select "all borders" . Our table gets a slender line.
	Now you need to make sure that the values ​​can be entered manually only into the cells that are intended for this purpose( so as not to erase or violate the formulas accidentally). Select the range of cells from B4 to B11 ( red arrows).Go to the menu "format" ( green arrow) and select the item "format cells" ( blue arrow).
	In the window that opens, select the last tab - "protection" and in the "protected cell" box, remove the checkmark.
	Now we again go to the menu "format" , and select the item "protect sheet" in it.
	A small window will appear, in which it will only be necessary to press the button "OK" .The offer to enter the password is simply ignored - in our document such a degree of protection is not needed. Now you can be sure that there will be no malfunction - only the cells in the column are opened in the value entry area. If you try to add anything to any other cells, a window will appear with a warning about the impossibility of such an operation.
	The calculator is ready. It remains only to save the file.- and he will always be ready for the calculation.
Illustration	Brief description of the operation

To work you need a normal Excel application, which is, probably, every user - it is included in the basic software package MicrosoftOffice. The compilation of a calculator will not be particularly difficult even for those users who have never encountered elementary programming questions.

Consider step-by-step:

( if part of the text in the table goes beyond, then there is an "engine" for horizontal scrolling below)

Do count in the created application - it's easy. It is enough only to fill in the known values ​​with the input area - the program will calculate everything in the automatic mode.

• The supply temperature and " return" of in the thermal control panel can be found in the ( boiler room) nearest to the house .
• The required temperature of the coolant in the intra-house system depends to a large extent on which heat exchange devices are installed in the apartments.
• Temperature in the pipe " return" system is usually taken equal to the same value in the central.
• The demand for a house in the total heat supply depends on the number of apartments, the heat exchange points( radiators), the building's features - the degree of its thermal insulation , of the volume of rooms, the amount of total heat loss and , .Usually these data are calculated in advance by still at the design stage of the house or with carrying out reconstruction of its heating system.
• The resistance coefficient of the internal heating circuit of a house is calculated according to individual formulas, with taking into account the features of the system. However, it will not be a big mistake to take and averaged values, given by in the table below:

Types of multi-apartment houses	Value of coefficient, m
Old-style apartment buildings, with heating circuits of steel pipes, without temperature controllers and coolant flow raterisers and radiators.	1
Houses commissioned or renovated during the period up to 2012, with the installation of polypropylene pipes for the heating system, without temperature controllers and flow of coolant on the risers and radiators	3 ÷ 4
Houses commissioned or after overhaulin the period after 2012, with the installation of polypropylene pipes for the heating system, without temperature controllers and coolant flow on risers and radiators.	2
The same, but with the installed heat and flow temperature controllers for risers and radiators	4 ÷ 6

Calculation and selection of the desired model of the

. We will try the calculator in action.

Let's assume that the temperature in the of the heat pipe feed pipe is 135, and in the reverse - 70 ° C .It is planned to maintain in the house heating system the temperature in 85 ° with , at the output - 70 ° C .For the qualitative heating of all rooms, a thermal power of 80 kW is required. According to the table, it is determined that the coefficient of resistance is equal to "1".

We substitute these values ​​in the corresponding calculator lines, and immediately get the necessary results:

. As a result, we have the data to select the desired model of the elevator and the conditions for its correct operation. So, the required system capacity is obtained - the amount of heat carrier pumped in a unit of time, the minimum head of the water column. And the most basic quantities are the diameters of the nozzle of the elevator and its neck( mixing chamber).

The diameter of the nozzle is to be rounded to the nearest hundredths of a millimeter in the smaller side ( in this case - 4.4 mm).The minimum diameter of the should be 3 mm - otherwise the nozzle will simply clog quickly.

The calculator allows you to "play" values, that is, to see how they will change when the original parameters change. For example, if the temperature in the heating plant is reduced, say, to 110 degrees, then this will involve and other parameters of the node.

As it is visible, the diameter of an elevator nozzle already makes 7,2 mm.

This gives the the option of selecting the device with the most acceptable parameters, with the defined by the adjustment range, or a set of replaceable nozzles for a particular model.

Having calculated data, it is already possible to refer to the tables of manufacturers of such equipment to select the required version.

Typically, in these tables, in addition to the calculated values, and other product parameters are given - its dimensions, flange dimensions, mass and .

For example - water jet steel elevators of the series 40s 10bk :

jet elevator Flanges: 1 - at the inlet, 1 - 1 - on the side of the pipe from the return , 1 - 2 - on the output.

2 - inlet connection.

3 - removable nozzle.

4 - reception camera.

5 - mixing throat.

7 - diffuser.

The main parameters are tabulated - for ease of choice:

Number elevator	Dimensions, mm	Weight kg	Estimated water flow from the network, t / h
dc	dg	D	D1	D2	l	L1	L
1	3	15	110	125	125	90	110	425	9,1	0,5-1
2	4	20	110	125	125	90	110	425	9,5	1-2
3	5	25	125	160	160	135	155	626	16,0	1-3
4	5	30	125	160	160	135	155	626	15,0	3-5
5	5	35	125	160	160	135	155	626	14,5	5-10
6	10	47	160	180	180	180	175	720	25	10-15
7	10	59	160	180	180	180	175	720	34	15-25

At the same time, the manufacturer allows the replacement of the nozzle with the required diameter in the with a specific range:

Model of elevator, No.	Possible range of nozzle change, Ø mm
No. 1	min 3 mm, max 6 mm
No. 2	min 4 mm, max 9 mm
No. 3	min 6 mm, max 10 mm
No. 4	min 7 mm, max 12 mm
No. 5	min 9 mm, max 14 mm
No. 6	min 10 mm, max 18 mm
No. 7	min 21mm, max 25 mm

Find the model you need, having the results of on hand - it will not be very difficult.

When mounting the elevator or during preventive maintenance, it must be taken into account that the efficiency of the unit depends on the correct installation and the integrity of the parts.

So, the nozzle cone( glass) must be installed strictly coaxially with the mixing chamber( with neck).The glass in the landing slot of the elevator must enter freely, so that it can be removed for revision or replacement.

When carrying out inspections, special attention should be paid to the condition of the surfaces of the elevator sections. Even the presence of filters does not exclude the abrasive action of the liquid, plus to this, does not go anywhere from erosive processes and corrosion. The working cone itself must have a polished inner surface, smooth, non-wound edges of the nozzle. If necessary, it is replaced by on the new part.

. Failure to comply with such requirements results in reducing the efficiency of the unit and the pressure drop required for the circulation of the heating medium in the inter-house heating distribution. In addition, wear of the nozzle, its contamination or too large diameter( much higher than the calculated one) will lead to the appearance of strong hydraulic noise, which will be transmitted through the heating pipes to the living quarters of the building.

Of course, the home heating system with the simplest elevator unit is far from a perfect example. It is quite difficult is amenable to adjustment, which requires disassembly of the unit and replacement of the injector nozzle. Therefore, the best option is seen, nevertheless, modernization with the installation of adjustable elevators, which allow changing the mixing parameters of the coolant in the defined by the range.

And how to regulate the temperature in the apartment?

The temperature of the coolant in the indoor network can be redundant for a single apartment, for example, if it uses " warm floors". Therefore, will require the installation of its own equipment, which will help maintain the degree of heating at the desired level.

Options like connect warm floors to heating - in a special article of our portal.

And finally - video with computer visualization of the device and the operation principle of the heating elevator:

Video: the device and operation of the elevator