Calculation and design programs for natural, supply and exhaust ventilation systems. Aspiration systems: types, device, installation selection criteria Calculation of an aspiration system with cyclones example

2. Calculated part 6

2.1. Calculation method 6

2.1.1. Calculation sequence 6

2.1.2. Determination of pressure loss in the duct 7

2.1.3. Determination of pressure loss in the manifold 8

2.1.4. Calculation of the dust collector 9

2.1.5. Calculation of the material balance of the dust collection process 11

2.1.6. Fan and motor selection 12

2.2. Calculation example 13

2.2.1. Aerodynamic calculation of the aspiration network (from local suction to the collector inclusive) 13

2.2.2. Linking the resistances of the sections 19

2.2.3. Calculation of pressure loss in the manifold 22

2.2.4. Calculation of the dust collector 23

2.2.5. Calculation of sections 7 and 8 before installing fan 25

2.2.6. Fan and motor selection 28

2.2.7. Refining the resistances of sections 7 and 8 29

2.2.8. Material balance of the dust collection process 31

Bibliography 32

Appendix 1 33

Appendix 2 34

Appendix 3 35

Appendix 4 36

Appendix 5 37

Appendix 6 38

Appendix 7 39

Appendix 8 40

Appendix 9 41

Appendix 10 42

Appendix 11 43

Appendix 12 44

Appendix 13 46

Appendix 14 48

1. General Provisions

In the processes of wood processing on woodworking machines, a large number of both large particles - production waste (shavings, wood chips, bark), and smaller ones (sawdust, dust). A feature of this technological process is the significant speed imparted to the formed particles when the cutting tool acts on the material being processed, as well as the high intensity of dust formation. Therefore, almost all woodworking machines are equipped with exhaust devices, which are usually called local suction.

A system that combines local suction, air ducts, a collector (a collector to which air ducts are connected - branches), a dust collector and a fan is called aspiration system.

The set of ducts - branches connected to the manifold is called knot.

On woodworking sites equipped with machines, collectors of various designs are used (Fig. 1). The characteristics of some types of collectors are given in table. 1.

To move the generated waste (for example, from the waste storage bins to the fuel bins of the boiler house), a pneumatic transport system is used; its difference from the aspiration system is that the local suction function is performed by a loading funnel.

The most important characteristic used in the calculations of aspiration and pneumatic transport systems is the mass concentration of dusty air (M, kg / kg). Mass concentration is the ratio of the amount of material being transported to the amount of air transporting it:

Rice. 1. Types of collectors:

a) vertical collector with bottom outlet (drum)

b) vertical collector with top outlet ("chandelier") c) horizontal collector

Table 1

kg / kg, (1)

where G Σ n- total mass flow rate of transported material, kg / h;

L Σ - the total amount of air required to move the material (volumetric flow rate), m 3 / h;

ρ v- air density, kg / m 3. At a temperature of 20 ° C and atmospheric pressure B = 101.3 kPa, ρ v = 1.21 kg / m 3.

When designing aspiration systems, an important place is occupied by aerodynamic calculation, which consists in choosing the diameters of air ducts, selecting a collector, determining velocities in sections, calculating and then linking pressure losses in sections, determining the total resistance of the system.

Production processes are often accompanied by the release of dusty elements or gases that pollute the air in the room. The problem will be solved by aspiration systems designed and installed in accordance with regulatory requirements.

Let's figure out how they work and where they use such devices, what are the types of air-cleaning complexes. Let's designate the main working units, describe the design standards and rules for installing aspiration systems.

Air pollution is an unavoidable part of many industrial processes. To comply with the established sanitary standards air purity, use aspiration processes. They can effectively remove dust, dirt, fibers and other similar impurities.

Aspiration is suction, which is carried out by creating an area in the immediate vicinity of the source of contamination reduced pressure.

To create such systems requires serious specialized knowledge and practical experience... Although the function of aspiration means is closely related to the function, not every ventilation specialist can cope with the design and installation of this type of equipment.

For achievement maximum efficiency combine ventilation and aspiration methods. The ventilation system in the production area must be equipped to ensure a constant supply of fresh air outside.

Aspiration is widely used in the following industrial areas:

• crushing production;
• wood processing;
• manufacturing of consumer products;
• other processes that are accompanied by the release of a large amount of substances harmful for inhalation.

It is far from always possible to ensure the safety of employees with standard protective equipment, and aspiration may become the only way to establish a safe production process in the workshop.

Suction units are designed for efficient and quick removal from the air of various small pollutants that are formed during industrial production

Removal of contaminants using systems of this type is carried out through special air ducts that have large angle tilt. This position prevents the appearance of so-called stagnation zones.

Mobile air handling units are easy to install and operate, they are perfect for small businesses or even a home workshop

An indicator of the efficiency of such a system is the degree of non-knockout, i.e. the ratio of the amount of contaminants that have been removed to the mass of harmful substances that did not enter the system.

There are two types of aspiration systems:

• modular systems- stationary device;
• monoblocks- mobile installations.

In addition, aspiration systems are classified according to the pressure level:

• low-pressure- less than 7.5 kPa;
• medium pressure- 7.5-30 kPa;
• high-pressure- over 30 kPa.

Complete set of aspiration system for modular and monoblock type is different.

In hot shops, heating of the air entering from the outside is not needed, it is enough to make an opening in the wall and close it with a damper.

Conclusions and useful video on the topic

Here is an overview of unpacking and installation mobile system aspiration RIKON DC3000 for the woodworking industry:

This video shows a stationary aspiration system used in furniture production:

Aspiration systems - modern and reliable way air purification in industrial premises from dangerous pollution. If the structure is correctly designed and installed without errors, it will demonstrate high efficiency at minimal cost.

Do you have anything to add, or do you have questions about aspiration systems? Please leave comments on the publication. The contact form is in the lower block.

Introduction

Local exhaust ventilation plays the most active role in the complex of engineering means for normalizing sanitary and hygienic working conditions in industrial premises. At enterprises related to the processing of bulk materials, this role is played by aspiration systems (AS), which ensure the localization of dust in the places of its formation. Until now, general ventilation has played an auxiliary role - it provided compensation for the air removed by the AU. Research of the Department of MOPE BelGTASM has shown that general ventilation is part of a complex of dust removal systems (aspiration, systems for combating secondary dust formation - hydraulic flushing or dry vacuum dust removal, general ventilation).

Despite the long history of development, aspiration has received a fundamental scientific and technical basis only in recent decades. This was facilitated by the development of fan engineering and the improvement of air purification from dust. The need for aspiration from the rapidly developing branches of the metallurgical construction industry also grew. A number of scientific schools have emerged aimed at solving emerging environmental problems. In the field of aspiration, the Ural (Butikov S.E., Gervasiev AM, Glushkov L.A., Kamyshenko M.T., Olifer V.D. and others), Krivorozhskaya (Afanasyev I.I., Boshnyakov E.N. ., Neykov O.D., Logachev I.N., Minko V.A., Serenko A.S., Sheleketin A.V. and the American (Hemeon V., Pring R.) schools that created modern foundations of design and methods calculation of localization of dust emissions using aspiration The technical solutions developed on their basis in the design of aspiration systems are enshrined in a number of normative and scientific-methodological materials.

Real methodological materials summarize the accumulated knowledge in the design of aspiration systems and centralized vacuum dust extraction (CPU) systems. The use of the latter is expanding, especially in production, where water washout is unacceptable for technological and construction reasons. The teaching materials intended for the training of environmental engineers complement the course “ Industrial ventilation"And provide for the development of practical skills among senior students of the specialty 17.05.09. These materials are aimed at ensuring that students are able to:

Determine the required performance of local AC suction and CPU nozzles;

Choose rational and reliable systems pipelines with minimal energy losses;

Define required power aspiration unit and choose the appropriate blowing agents

And they knew:

The physical basis for calculating the performance of local NPP suctions;

The fundamental difference hydraulic calculation CPU systems and AC duct networks;

Constructive design of shelters for transfer units and CPU nozzles;

Principles of ensuring the reliability of AC and CPU operation;

The principles of selection of the fan and the features of its operation for a specific pipeline system.

Methodical instructions focused on solving two practical problems: "Calculation and selection of aspiration equipment (practical task No. 1)," Calculation and selection of equipment for vacuum system for cleaning dust and spills (practical task No. 2) ".

The approbation of these tasks was carried out in the fall semester of 1994 at practical exercises groups AG-41 and AG-42, to whose students the compilers express their gratitude for the inaccuracies and technical errors they identified. Careful study of materials by students V.A. Titov, G.N. Seroshtan, G.V. Eremina. gave us a reason to make changes to the content and edition of the guidelines.

1. Calculation and selection of aspiration equipment

Purpose of the work: determination of the required performance of the aspiration installation serving the system of aspiration shelters for the loading points of the belt conveyors, the choice of the air duct system, dust collector and fan.

The assignment includes:

A. Calculation of the productivity of local suction (aspiration volumes).

B. Calculation of the dispersed composition and concentration of dust in the aspirated air.

B. Choice of dust collector.

D. Hydraulic calculation of the aspiration system.

E. The choice of the fan and the electric motor to it.

Initial data

(The numerical values ​​of the initial values ​​are determined by the number of variant N. Values ​​for variant N = 25 are indicated in brackets).

1. Consumption of transported material

G m = 143.5 - 4.3N, (G m = 36 kg / s)

2. Density of particles of bulk material

2700 + 40N, (= 3700 kg / m 3).

3. Initial moisture content of the material

4.5 - 0.1 N, (%)

4. Geometrical parameters of the transfer chute (Fig. 1):

h 1 = 0.5 + 0.02N, ()

h 3 = 1–0.02N,

5. Types of shelters for the loading site of the belt conveyor:

0 - shelters with single walls (for even N),

D - shelters with double walls (for odd N),

Conveyor belt width B, mm;

1200 (for N = 1 ... 5); 1000 (for N = 6 ... 10); 800 (for N = 11 ... 15),

650 (for N = 16 ... 20); 500 (for N = 21 ... 26).

S W is the cross-sectional area of ​​the gutter.

Rice. 1. Aspiration of the reloading unit: 1 - upper conveyor; 2 - upper shelter; 3 - reloading chute; 4 - lower shelter; 5 - aspiration funnel; 6 - side outer walls; 7 - side inner walls; 8 - hard internal partition; 9 - conveyor belt; 10 - end outer walls; 11 - end inner wall; 12 - bottom conveyor

Table 1. Geometric dimensions of the lower shelter, m

Table 2. Granulometric composition of the transported material

* z = 100 (1 - 0.15).

Table 3. Length of sections of the aspiration network

Rice. 2. Axonometric diagrams of the aspiration system of reloading units: 1 - reloading unit; 2 - aspiration pipes (local suction); 3 - dust collector (cyclone); 4 - fan

2. Calculation of the performance of local suction

The calculation of the required volume of air removed from the shelter is based on the air balance equation:

The flow rate of air entering the shelter through the leak (Q n; m 3 / s) depends on the area of ​​the leaks (F n, m 2) and the optimal value of rarefaction in the shelter (R y, Pa):

(2)

where is the density of the ambient air (at t 0 = 20 ° С; = 1.213 kg / m 3).

To cover the loading points of the conveyor, leaks are concentrated in the zone of contact of the outer walls with the moving conveyor belt (see Fig. 1):

where: P - perimeter of the shelter in the plan, m; L 0 - length of the shelter, m; b is the width of the shelter, m; - the height of the conditional slot in the contact zone, m.

Table 4. The value of rarefaction in the shelter (P y) and the width of the slot ()

Air flow entering the shelter through the chute, m 3 / s

(4)

where S is the cross-sectional area of ​​the gutter, m 2; - the flow rate of the material to be overloaded at the exit from the chute (final speed of falling particles), is determined sequentially by calculation:

a) speed at the beginning of the chute, m / s (at the end of the first section, see Fig. 1)

, G = 9.81 m / s 2 (5)

b) speed at the end of the second section, m / s

(6)

c) speed at the end of the third section, m / s

- slip coefficient of components ("ejection coefficient") u - air velocity in the chute, m / s.

The slip coefficient of the components depends on the Butakov – Neykov number *

(8)

and Euler's criterion

(9)

where d is the average particle diameter of the material being reloaded, mm,

(10)

(if it turns out that, it should be taken as the calculated average diameter; - the sum of the coefficients of local resistance (c.m.c.) of the gutter and shelters

(11)

ζ in - cms, air inlet into the upper shelter, referred to the dynamic air pressure at the end of the trough.

; (12)

F in - area of ​​leaks of the upper shelter, m 2;

* The Butakov – Neykov and Euler numbers are the essence of the parameters M and N, which are widely used in normative and educational materials.

- Ph.D. gutters (= 1.5 for vertical gutters, = 90 °; = 2.5 in the presence of an inclined section, i.e. 90 °); –C.m.s. a rigid partition (for a "D" type shelter; in a "0" type shelter there is no rigid partition, in this case ln = 0);

Table 5. Values ​​for "D" type shelter

Ψ is the drag coefficient of the particle

(13)

β - volumetric concentration of particles in the chute, m 3 / m 3

(14)

- the ratio of the flow rate of particles at the beginning of the chute to the final flow rate.

With the found numbers B u and E u, the slip coefficient of the components is determined for a uniformly accelerated flow of particles by the formula:

(15)

The solution to equation (15) * can be found by the method of successive approximations, assuming as the first approximation

(16)

If it turns out that φ 1

, (17)

(18)

(20)

Let us consider the calculation procedure using an example.

1. Based on the given particle size distribution, we construct an integral graph of the particle size distribution (using the previously found integral sum m i) and find the median diameter (Fig. 3) d m = 3.4 mm> 3 mm, i.e. we have a case of overloading lumpy material and, therefore, = 0.03 m; P y = 7 Pa (Table 4). In accordance with formula (10), the average particle diameter .

2. According to the formula (3) we determine the area of ​​leaks of the lower shelter (bearing in mind that L 0 = 1.5 m; b = 0.6 m, with B = 0.5 m (see Table 1)

F n = 2 (1.5 + 0.6) 0.03 = 0.126 m 2

3. According to the formula (2), we determine the flow rate of air entering through the leaks of the shelter

There are other formulas for determining the coefficient incl. for a stream of small particles, the speed of which is affected by air resistance.

Rice. 3. Integral graph of particle size distribution

4. Using formulas (5) ... (7) we find the flow rate of particles in the chute:

hence

n = 4.43 / 5.87 = 0.754.

5. According to the formula (11) we determine the sum of the c.m.with. gutters taking into account the resistance of the shelters. With F in = 0.2 m 2, according to formula (12), we have

With h / H = 0.12 / 0.4 = 0.3,

according to table 5 we find ζ n ep = 6.5;

6. Using the formula (14), we find the volume concentration of particles in the trough

7. Using the formula (13), we determine the drag coefficient
particles in the chute

8. Using formulas (8) and (9), we find, respectively, the Butakov – Neykov number and the Euler number:

9. Determine the coefficient of "ejection" in accordance with the formula (16):

And, therefore, you can use the formula (17) taking into account (18) ... (20):

10. Using the formula (4), we determine the flow rate of air entering the lower shelter of the first transfer unit:

In order to reduce calculations, let us set the flow rate for the second, third and fourth reloading nodes

K 2 = 0.9; k 3 = 0.8; k 4 = 0.7

We enter the result of calculations in the first row of the table. 7, assuming that all reloading nodes are equipped with the same shelter, the flow rate of air entering through the leaks of the i-th reloading unit is Q n i = Q n = 0.278 m 3 / s. The result is entered into the second row of the table. 7, and the amount of expenses Q w i + Q n i - in the third. The sum of costs, - represents the total productivity of the aspiration unit (air flow rate entering the dust collector - Q n) and is entered in the eighth column of this line.

Calculation of the disperse composition and concentration of dust in aspirated air

Dust density

The flow rate of air entering the exit along the chute - Q zhi (through leaks for a shelter of the "O" type - Q ni = Q H), removed from the shelter - Q ai (see Table 7).

Geometric parameters of the shelter (see Fig. 1), m:

length - L 0; width - b; height - N.

Cross-sectional area, m:

a) aspiration pipe F in = bc .;

b) a shelter between the outer walls (for departure of the "O" type)

c) a shelter between the inner walls (for a type “D” shelter)

where b is the distance between the outer walls, m; b 1 - the distance between the inner walls, m; H is the height of the shelter, m; с - length of the inlet section of the aspiration branch pipe, m.

In our case, at B = 500 mm, for a shelter with double walls (type “D” shelter) b = 0.6 m; b 1 = 0.4 m; C = 0.25 m; H = 0.4 m;

F inx = 0.25 0.6 = 0.15 m 2; F 1 = 0.4 0.4 = 0.16 m 2.

Removing the aspiration funnel from the gutter: a) for a “0” type shelter L y = L; b) for a “D” type shelter L y = L –0.2. In our case, L y = 0.6 - 0.2 = 0.4 m.

Average air speed inside the shelter, m / s:

a) for a type "D" shelter

b) for shelter type "0"

= (Q w + 0.5Q H) / F 2. (22)

Air entry speed into the aspiration funnel, m / s:

Q a / F in (23)

Diameter of the largest particle in aspirated air, microns:

(24)

According to the formula (21) or according to the formula (22), we determine the air speed in the shelter and the result is entered in row 4 of the table. 7.

Using the formula (23), we determine the speed of air entry into the aspiration funnel and enter the result in line 5 of the table. 7.

Using the formula (24), we determine and enter the result in line 6 of the table. 7.

Table 6. Mass content of dust particles, depending on

The values ​​corresponding to the calculated value (or the closest value) are written out from the column of Table 6 and the results (in shares) are entered into rows 11 ... 16 of columns 4 ... 7 of Table. 7. You can also use linear interpolation of table values, but keep in mind that as a result we will get, as a rule, and therefore you need to adjust the maximum value (to ensure).

Determination of dust concentration

Material consumption -, kg / s (36),

The density of the material particles is, kg / m 3 (3700).

Initial material moisture -,% (2).

The percentage of finer particles in the material being reloaded -,% (at = 149 ... 137 microns, = 2 + 1.5 = 3.5%. Dust consumption, reloaded with the material - , g / s (103.536 = 1260).

Aspiration volumes -, m 3 / s ( ). Entrance speed to the aspiration funnel -, m / s ( ).

The maximum concentration of dust in the air removed by local suction from the i-th shelter (, g / m 3),

, (25)

Actual dust concentration in the aspirated air

where is the correction factor determined by the formula

wherein

for “D” type shelters, for “O” type shelters; in our case (at kg / m 3)

Or at W = W 0 = 2%

1. In accordance with the formula (25), we calculate and enter the results in the 7th row of the summary table. 7 (the specified dust consumption is divided by the corresponding numerical value of row 3, and the results are entered in row 7; for convenience, in the note, i.e., in column 8, we enter the value).

2. In accordance with the formulas (27 ... 29) at the established humidity, we build a calculated ratio of the type (30) to determine the correction factor, the values ​​of which are entered in line 8 of the summary table. 7.

Example. Using the formula (27), we find the correction coefficient psi and m / s:

If the dust content of the air turns out to be significant (> 6 g / m 3), it is necessary to provide engineering methods to reduce the concentration of dust, for example: hydro-irrigation of the overloaded material, decrease in the speed of air entry into the aspiration funnel, installation of settling elements in the shelter or the use of local suction - separators. If by means of water irrigation it is possible to increase the humidity up to 6%, then we will have:

(31)

At = 3.007, , = 2.931 g / m 3 and as a calculated ratio for we use relation (31).

3. Using the formula (26), we determine the actual concentration of dust in the I-th local suction and enter the result in line 9 of the table. 7 (the values ​​of line 7 are multiplied by the corresponding i-th suction - the values ​​of line 8).

Determination of the concentration and dispersed composition of dust in front of the dust collector

For selection dust collection unit of the aspiration system serving all local suctions, it is necessary to find the average parameters of the air in front of the dust collector. To determine them, the obvious balance ratios of the laws of conservation of the mass of dust transported through the air ducts are used (assuming that the deposition of dust on the walls of the air ducts is negligible):

For the concentration of dust in the air entering the dust collector, we have an obvious relationship:

Bearing in mind that the expense dust j-i fractions in the i-th local suction

It's obvious that

(36)

1. Multiplying in accordance with the formula (32) the values ​​of line 9 and line 3 of the table. 7, we find the dust consumption in the i-th suction, and enter its values ​​in line 10. The sum of these costs will be entered in column 8.

Rice. 4. Distribution of dust particles by size before entering the dust collector

Table 7. The results of calculating the volumes of aspirated air, dispersed composition and concentration of dust in local suction and in front of the dust collector

2. Multiplying the values ​​of line 10 by the corresponding values ​​of lines 11 ... 16, we obtain, in accordance with formula (34), the value of the dust consumption of the j-th fraction in i-th local suction. We enter the values ​​of these quantities on lines 17 ... 22. The line-by-line sum of these values, put down in column 8, represents the consumption of the j-th fraction in front of the dust collector, and the ratio of these sums to the total dust consumption in accordance with formula (35) is the mass fraction of the j-th fraction of dust entering the dust collector. The values ​​are entered in column 8 of the table. 7.

3. Based on the calculated as a result of constructing the integral graph of the distribution of dust particles by size (Fig. 4), we find the size of dust particles, finer than which the original dust contains 15.9% of total mass particles (μm), median diameter (μm) and dispersion of the particle size distribution: .

Inertial dry dust collectors - cyclones of the TsN type; inertial wet dust collectors - cyclones - SIOT probes, coagulation wet dust collectors KMP and KCMP, rotoclones; contact filters - bag and granular.

For reloading of unheated dry bulk materials, NIOGAZ cyclones are usually used with a dust concentration of up to 3 g / m 3 and microns, or bag filters at high dust concentrations and smaller particle sizes. At enterprises with closed water supply cycles, inertial wet dust collectors are used.

Purified air consumption -, m 3 / s (1.7),

Dust concentration in the air in front of the dust collector -, g / m 3 (2.68).

Dispersed composition of dust in the air in front of the dust collector - (see Table 7).

The median diameter of dust particles is, μm (35.0).

Dispersion of particle size distribution - (0.64),

Density of dust particles -, kg / m 3 (3700).

When choosing the cyclones of the TsN type as a dust collector, the following parameters are used (Table 8).

aspiration conveyor hydraulic air duct

Table 8. Pressure drop and efficiency of cyclones

Permissible concentration of dust in the air, emitted into the atmosphere, g / m 3

At m 3 / s (37)

At m 3 / s (38)

Where the coefficient taking into account the fibrogenic activity of dust is determined depending on the value of the maximum permissible concentration (MPC) of dust in the air working area:

Required degree of air purification from dust,%

(39)

Estimated degree of air purification from dust,%

where is the degree of air purification from dust j-th fractions,% (fractional efficiency - taken according to reference data).

Dispersed composition of many industrial dust (at 1< <60 мкм) как и пофракционная степень их очистки и инерционных пылеуловителю подчиняется логарифмически нормальному закону распределения, и общая степень очистки определяется по формуле :

, (41)

wherein

, (42)

where is the diameter of particles captured by 50% in a cyclone with a diameter D c at an average air velocity in its cross section,

, (43)

- dynamic coefficient of air viscosity (at t = 20 ° С, = 18.09–10–6 Pa – s).

Integral (41) is not resolved in quadratures, and its values ​​are determined by numerical methods. Table 9 shows the values ​​of the function found by these methods and borrowed from the monograph.

It is easy to establish that

, , (44)

, (45)

this is the integral of probability, the tabular values ​​of which are given in many mathematical reference books (see, for example,).

We will consider the calculation procedure on a specific make-up artist.

1. Permissible concentration of dust in the air after its purification in accordance with formula (37) at MPC in the working area of ​​10 mg / m 3 ()

2. The required degree of air purification from dust according to the formula (39) is

Such cleaning efficiency for our conditions (μm and kg / m 3) can be provided by a group of 4 cyclones TsN-11

3. Determine the required cross-sectional area of ​​one cyclone:

m 2

4. Determine the design diameter of the cyclone:

m

We select the closest of the normalized range of cyclone diameters (300, 400, 500, 600, 800, 900, 1000 mm), namely m.

5. Determine the air speed in the cyclone:

m / s

6. Using formula (43), we determine the diameter of particles captured in this cyclone by 50%:

micron

7. Using the formula (42), we determine the parameter X:

.

The result obtained, based on the NIOGAZ method, assumes a log-normal law of the particle size distribution of dust particles. In fact, the dispersed composition of dust, in the area of ​​large particles (> 60 microns), in the air aspirated for shelters of conveyor loading points differs from the normal-logarithmic law. Therefore, the calculated degree of purification is recommended to be compared with the calculations according to formula (40) or with the methodology of the MOPE department (for cyclones), based on a discrete approach to the one fully covered in the course "Aerosol Mechanics".

An alternative way to determine the reliable value of the total degree of air purification in dust collectors is to set up special experimental research and comparing them with the calculated ones, which we recommend for an in-depth study of the process of air purification from particulate matter.

9. The concentration of dust in the air after cleaning is

g / m 3,

those. less than permissible.

At present, aspiration systems are quite common, since the development of the industry only intensifies every day.

General information

Filtration plants with are common systems which are the most common. They are designed to filter air containing solid particles up to 5 microns in size. The degree of purification of such aspiration systems is 99.9%. It is also worth noting that the design of this filter unit, which has a storage hopper, allows it to be used for installation in traditional air purification systems that have a branched air duct system, as well as exhaust fan high power.

The central storage in such systems is used in order to store, as well as dose and dispense shredded woodworking waste. The production of this bunker is carried out with a volume of 30 to 150 m 3. In addition, the aspiration system is completed with such details as sluice loaders or augers, an explosion-fire protection system, a system that controls the level of filling the bunker.

Modular systems

There is also modular system air aspiration, which is intended for the following purposes:

• Ensure complete and reliable dedusting of air in the production area at the level prescribed by the regulations.
• Most important task- protection of atmospheric air from its pollution by the enterprise.
• Also, this system is designed to remove woodworking production waste from technological equipment in the form of a mixture of air and dust, as well as the subsequent supply of this mixture to dust collecting devices.
• The modular system is also designed to organize the emission of emissions from the place of air purification to the place of its disposal. It can function fully automatic mode.
• The last function that this system performs is the metering of sawdust to the fuel hopper. This operation can also function in a fully automatic mode, but a manual one is also present.

Calculation equipment

In order to calculate the aspiration system, you first need to combine it into a common network. Such networks include:

1. Equipment that functions at the same time.
2. Equipment that is close to each other.
3. Equipment with the same dust or similar in quality and properties.
4. The last thing to consider is equipment with close or the same air temperature.

It is also worth noting that the optimal number of suction points for one aspiration system is six. However, more is possible. It is important to know that in the presence of equipment that works with a constantly changing air flow, it is necessary to design a separate aspiration system for this device, or add to the already existing small number of "passing" suction points (one or two with a low flow rate).

Air calculation

For it is important to make accurate calculations. The first thing that is determined in such calculations is the air consumption for aspiration, as well as the pressure loss. Such calculations are carried out for each machine, container or point. Data can most often be taken from the passport documentation for the object. However, it is allowed to use AI and from similar calculations with the same equipment, if any. Also, the air flow can be easily determined by the diameter of the nozzle that sucks it off, or by the hole in the body of the aspiration machine.

It is important to add that it is possible to eject the air entering the product. This happens if, for example, air moves through a gravity pipe at high speed. In this case, his additional costs arise, which must also be taken into account. In addition, in some aspiration systems it also happens that a certain amount of air escapes along with the discharged products after cleaning. This amount must also be added to the expenditure.

Consumption calculation

After carrying out all the work on determining the air flow rate and possible ejection, it is necessary to add up all the numbers obtained, and then divide the amount by the volume of the room. It should be borne in mind that the normal exchange of air for each enterprise is different, but most often this indicator is in the range from 1 to 3 aspiration cycles per hour. A larger number is most often used for calculating the installation of systems in rooms with a general exchange This type air exchange is used in enterprises to remove harmful vapors from the room, to remove impurities or unpleasant odors.

When installing an aspiration system, an increased vacuum can be created due to the constant suction of air from the room. For this reason, it is necessary to provide for the installation of an inflow of outside air into it.

Fire aspiration

Currently aspiration fire system counts the best remedy protection of the premises. In an effective way alert in this case is considered an aspiration with ultrasensitive laser. Ideal place of application of such systems are archives, museums, server rooms, switch rooms, control centers, hospital rooms with high-tech equipment, "clean" industrial areas, etc.

In other words, the aspiration system fire alarm This type is used in premises that are of particular value, in which material values ​​are stored or, inside which a large amount of expensive equipment is installed.

Closed suction system

Its purpose is as follows: sanitation of the tracheobronchial tree under conditions of artificial lung ventilation and while maintaining asepsis. In other words, they are used by doctors to carry out complex operations. This system includes the following:

• The design of the device is made entirely of polyethylene, polyvinyl chloride, polypropylene. Its latex content is zero.
• The device contains a fully standardized swivel elbow connector and a movable inner ring. The presence of this part ensures a reliable connection with the connector.
• The system is equipped with a protective sheath for the sanitation catheter, which is designed to contain this part in a sealed environment.
• Catheter sizes are color coded.

Types of systems

Currently, there is a fairly broad classification of types of filter systems. Some companies, such as Folter, are engaged in the production of aspiration systems of almost any kind.

The first division of systems is carried out according to the nature of air circulation. On this basis, all of them can be divided into two types: recirculating and direct-flow. The first class of systems has such a significant difference as the return of the sampled air from the room back after going through a complete cleaning process. That is, it does not produce any emissions into the atmosphere. One more advantage follows from this advantage - high savings on heating, since the heated air does not leave the room.

If we talk about the second type of systems, then their principle of operation is completely different. This filtering unit completely takes air from the room, after which it completely cleans it, in particular from substances such as dust and gas, after which all the taken air is discharged into the atmosphere.

Installation of aspiration systems

In order to start the stage of installing the filtration system, design work is first carried out. This process is very important, and therefore it is given Special attention... It is important to say right away that an incorrect design and calculation stage will not be able to provide the necessary cleaning and air circulation, which will lead to bad consequences. For the successful preparation of the project and the subsequent installation of the system, several points must be taken into account:

1. It is important to determine the amount of consumed air per aspiration cycle, as well as the pressure loss at each point of its intake.
2. It is important to correctly determine the type of dust collector. To do this, you need to choose the right one according to its parameters.

Carrying out calculations and drawing up a project is not a complete list of what needs to be done before starting the process of installing the system. In other words, we can say that installing filters is the simplest and last thing that professionals take on.

Many programs have been created to help engineers who design and calculate ventilation. The computer will not only calculate all the required parameters, but also make ventilation drawings. Read about the most convenient and simple solutions, as well as what the algorithm of their work is based on.

Ventilation calculation software Vent-Calc

Vent-Calc design software is one of the most functional and affordable. The algorithm of its work is based on the Altshul formulas. Hydraulic calculations of air ducts are made according to the method taken from the "Designer's Handbook" edited by Staroverov. It copes equally well with the calculation of natural and forced ventilation.

Ventilation program functionsVent-Calc:

• Calculation of air ducts taking into account the temperature and speed of movement of flows, air consumption;
• Calculation of hydraulic air ducts;
• Calculation of local resistances (constrictions, bends, extensions and forks) of room channels. The coefficients of resistance are calculated in different sections of the system, the pressure loss in Pascals, the program selects ventilation equipment... To verify the correctness of the calculations, tables BCH 353-86 are attached. During operation, the ventilation program directs the user to the required formulas and tables;
• Suitable for calculation natural ventilation premises. The optimal section of the ventilation duct is determined, which ensures the prevalence of thrust over air resistance at a given air flow rate;
• Calculates the heating power by an air heater or any other type of air heater.

This program for calculating ventilation systems is very good for students who are just taking a ventilation course at the university. Another advantage is its free distribution.

The latest revision of the ventilation design software Vent-Calc allows for as soon as possible calculate the aerodynamic resistance of the system and other indicators required for the preliminary selection of equipment. This requires the following indicators:

• the length of the main air duct of the room;
• air consumption at the beginning of the system;
• air flow at the end of the system.

Manually, such a calculation is quite laborious and is carried out in stages. Therefore, the software for calculating Vent-Calc will facilitate and speed up the work of designers, sales specialists. climatic technology and qualified installers.

The program for the design of engineering systems MagiCAD

This is a program for the design of ventilation, heating, water supply and sewerage systems, power grids. MagiCAD calculates and makes the necessary drawings.

It will be useful for builders, designers, draftsmen and equipment sales managers.

MagiCAD functions:

• all types of calculations for ventilation systems(supply and exhaust);
• image in 2D;
• image in 3D;
• the widest database of equipment from European manufacturers;
• creation of all necessary project documentation, including specifications;
• the ability to exchange data with other programs for drawing ventilation;
• compatibility with ADT and AutoCAD.

MagiCAD graphics are based on AutoCAD and are in fact complementary to it. The program was created by Finnish developers who made it as easy as possible to use. Therefore, an engineer familiar with AutoCAD will easily deal with the subsidiary program for calculating ventilation and other engineering systems MagiCAD. Ease of use is achieved by dividing the core into modules: Ventilation, Piping, Electricity and Premises.

The specialist does not need to draw complex air distribution networks, fittings and bends. Ready-made elements are composed like a constructor. You don't even need a ruler. The main job of the designer is to properly arrange the existing units for optimal results. All data about the project is present right there. Looking at the electronic drawing, you can get the necessary information about the operation of future ventilation, for example, about the cross-section of the air ducts and the speed of the air flow in them.

The program for calculating ventilation systems MagiCAD is used by dozens of large design bureaus in the Scandinavian countries and many design organizations in the CIS countries.

Calculation program for natural ventilation and aspiration GIDRV 3.093

The GIDRV 3.093 program is designed to calculate ventilation systems with forced and natural draft. It is a multitasking form with a set of tabs: "Scheme characteristics", "Floors", "Plots", "Local resistances", "Calculation table".

Functions of the program for calculating natural ventilation GIDRV 3.093:

• control calculation of the parameters of the natural ventilation exhaust duct;
• calculation of new and control calculation of air ducts for aspiration;
• calculation of new and control calculations of supply and exhaust air ducts for forced draft systems.

Having received the results, you can change the initial parameters at any sections of the ducts and make new scheme... With this program, any combination can be selected to calculate the natural ventilation to achieve optimal performance.

Diagrams with explanations (channel characteristics, system impedances, calculation results) are stored in a single file. Switching and working with different options calculations are very convenient and simple.

Areas with excessive pressure are automatically identified and options for solving the problem are provided (to narrow the section, use diaphragms, gate valves, chokes).

The program for calculating natural ventilation is equipped with a function for calculating throttling mechanisms, which gives out several best options and indicating the most suitable one.

In the process of calculating natural ventilation, it detects the most congested sections of the system. Shows the pressure for each section, losses and their causes (pipe resistance, friction).

All calculations can be printed, including tables.

Paid, but a demo version is available for review.

Fans 400 smoke ventilation calculation program

The Fans 400 program is designed for calculating smoke ventilation in premises. It can be used to determine the performance of the smoke extraction system from hallways, corridors and lobbies. The program for calculating smoke ventilation helps to select the power of fans and other special equipment.

Fans 400 is designed for design engineers, fire inspectors and specialized students.

The use of smoke ventilation for calculations will not cause difficulties for a user of any level of training. It is distributed free of charge. For the program to work correctly, you need to connect a printer to your computer.

Ducter 2.5 duct selection software

This ventilation equipment selection program calculates the cross-sectional diameters of the air ducts. The user enters the maximum values ​​of the flow rate in the ducts, height differences when calculating natural ventilation or the CMC of a segment. Based on this information, the program selects ventilation equipment of standard diameter according to VSN 353-86 linearly. Thus, the final decision on the diameter remains with the specialist.

If you need an air duct of non-standard parameters, the program will also help: one parameter is entered, the rest are selected. The selection step is set in the settings.

Indicators of pressure and air temperature are set if the air conditioning system is calculated. It is possible to obtain data on the pressure at each section by entering its length and the total coefficient of resistance. The material of the future duct is taken into account.

You can set one of several options for displaying the dimensions of each parcel.

Versions of the program from Ducter 3 and higher for the selection of equipment will help to fully calculate the entire ventilation system.

The program for drawing ventilation "SVENT"

SVENT program is designed for drawing room ventilation on Windows computers.

SVENT functions:

• aerodynamic calculation of forced and exhaust ventilation systems;
• a program for ventilation drawings in perspective, uses elements of AutoCAD;
• draws up specifications.

Performs 2 types of calculations:

• Automatically proposes a rectangular or circular cross-section based on the entered speed data near the fans and at the ends of the air ducts;
• Calculation of the system with the entered data on cross-sections and pressure losses.

The calculation program works with any types of air ducts (round, rectangular and non-standard). You can supplement the database of air ducts with the necessary samples.

The base of nodes works on the schemes for calculating the coefficients of local resistances from VSN 353-86, Designer's Guide, edited by I.G. Staroverov. and several other sources. It can also be supplemented.

Ventilation drawing software CADvent

This ventilation drawing program is based on the powerful and sophisticated AutoCAD. Along with the development of AutoCAD, CADvent is modified and improved, new features are added. These are professional programs for ventilation drawing, calculations and presentations, created for engineers working in the design and development of ventilation, air conditioning and heating systems.

CADvent functions:

• calculation of the cross-section of air ducts;
• calculation of pressure losses;
• acoustic calculation;
• creation of a 2D drawing with the necessary designations;
• 3D modeling;
• element specification, which can be transferred to MS excel;
• creation of presentations.

CADvent software provides the ability to change any changes already finished project, change design parameters, add new elements. It can be combined with the programs DIMsilencer (program for selecting a sound attenuator in a ventilation system) and DIMcomfort (selects air distributors, taking into account the flow rate and noise in places where people are).

Users note the ease of use, but there is a lack of Russification, as well as the ability to create an axonometric projection.

Watch the video about another program called Comfort-B.