home · electrical safety · The principle of operation and manufacture of a smoke generator for smoking with your own hands. Flue gas purification plants Optimal installation design for cold smoking

The principle of operation and manufacture of a smoke generator for smoking with your own hands. Flue gas purification plants Optimal installation design for cold smoking

The difficulty is that smoking is a lengthy process and requires not only the proper equipment, but also a substantial supply of firewood if you are using a traditionally designed smokehouse that burns wood. This smoking lasts up to several days with constant combustion in the firebox.

But inventive thought also found a way out of this situation - a smoke generator for a smokehouse. The main and only purpose of the smoke generator is to produce a significant amount of smoke and supply it to the smoking cabinet, where the preparations for smoking are located. As a result of interaction with smoke of specially marinated meat, fish or poultry, a number of chemical reactions, turning them into highly digestible and very tasty products.

A smoke generator for a smokehouse is a fairly simple, but extremely effective device that can be made with your own hands from scrap materials. The whole attractiveness of the smoke generator is that it can work in automatic mode. The temperature in the smoking cabinet is not too high, so there is no need to worry about the food burning.

Smoke generator design

Conventional drawing of a smoke generator

The source of smoke is sawdust, shavings or wood chips that slowly smolder inside the generator. The secret to installation is how to ensure consistent, even combustion and how to feed smoke into the smoking cabinet. To assemble a smoke generator for a smokehouse in a home workshop you will need:

Components are readily available and inexpensive


As you can see, the list is not very long, and all the components can be easily bought in a store or, after a good search, found in your own garage or home workshop. Drawings and instructions for assembling a smoke generator for a smokehouse are abundant on the Internet.

To build a smoke generator with your own hands, you will need more welding machine, grinder and some skills in working with them. The main difficulty is welding the chimney fitting to the pipe, making doors for the firebox and removable bottom and top covers. But first things first.

Smoke generator assembly steps

The first step is to cut a piece 0.5 - 0.8 m long from the pipe intended for the housing. To fit its external dimensions from sheet metal The bottom and cover are made. The bottom should have side sides so that the body fits tightly inside and the ashes from burnt sawdust do not spill out. In the side of the body, just above the bottom shoulder, several holes are drilled, which serve to ignite the fuel and provide oxygen for combustion. Their diameter is 0.6 – 0.8 cm.

It is necessary to make a hole in the smoke generator housing for ignition and oxygen access

For ease of use and stability of the smoke generator, legs 15–20 cm high or a flat platform are welded to the base.

If there is a removable bottom, doors for the firebox in the side wall are not needed. If the bottom is solid, then you need to make side doors on hinges, with slots for air flow, like stove doors. This is a little more complicated, but it is quite possible to do it yourself. The top cover is solid, without a chimney or ventilation holes. It should also fit tightly onto the pipe and be equipped with a handle - a bracket for opening the smoke generator.

A chimney outlet is welded into the upper part of the body, at a distance of 5–8 cm from the pipe cut. The fitting is welded perpendicular to the wall and should protrude 6–8 cm from the wall. Before welding, a thread must be cut at its outer end for the fitting (tee). After connecting the chimney, a tee and two tubes are connected to it - one goes down, the other to the smokehouse.

One of the options for a smoke generator for a smokehouse with a tee

The tube from the compressor is connected to the fitting going down, and the connecting pipe leading to the smoking cabinet is connected to the side one. As a fan, you can use a compressor from an aquarium, a cooler from a computer, or something similar - it is important to create a not too powerful, but constant flow of air directed towards the container in which smoking occurs.

A compressor can be made from a cooler and a bottle

As an option, the tee can be connected to the smoke generator cover without affecting the integrity of the side wall. In this case, the lower fitting is connected to the lid, the rear one to the air duct from the compressor, and the front one to the smokehouse.

Smoke generator for smokehouse with top tee

That's all - the smoke generator for the smokehouse is ready.

How it works

A smokehouse with a smoke generator, built with your own hands, is very mobile and compact. When not in use, it can be stored in a garage, basement, or even a closet. This depends on what is used as a smokehouse. You can use any metal box for the camera suitable size. If there is no ready-made one, then you can make it yourself without any problems. The box sizes vary, depending on the volume of product you will be smoking.

For home smoking, the optimal dimensions are 1.0 / 0.6 / 0.6 m (H / W / D). The top of the box is closed with a lid with a built-in thermometer and several small (0.3 -0.5 mm) holes to create traction. Top part The smokehouse in working condition should be located above the smoke generator - this creates additional natural draft, and even when the fan stops, smoke will enter the chamber without delay.

Now you need to assemble everything:

  1. We install the generator on a fireproof base - a metal table, concrete slab or gender, ceramic tiles. This must be done for reasons fire safety. In addition to the fact that the smoke generator gets quite hot, pieces of burning wood chips may fall out of it.
  2. We load approximately 0.5 - 1 liter of dry wood chips, sawdust, shavings into the smoke generator deciduous trees(conifers are not used for smoking) and close it tightly with a lid.
  3. We connect the compressor pipe and connect the chimney to the smoking chamber.
  4. We ignite the fuel through the side hole.
  5. Turn on the fan.

The smoking process has begun. The tee with the fan acts as an injector. A vacuum is created in the chimney pipe, which causes smoke to be drawn in from the generator, and a rather noticeable air-smoke flow is directed towards the smoking cabinet. At the same time, an influx of air into the firebox from the outside is formed, through the side openings in the smoke generator. The combustion is self-sustaining and no human intervention is required.

The temperature inside the cabinet is controlled by means of a thermometer inserted into the smokehouse.

By increasing or decreasing the length of the chimney, you can regulate the smoking temperature, therefore, use hot or cold smoking. For hot smoking, the smoke generator fitting is directly connected to the smoking chamber.

The dimensions of the smoke generator are average. When building it with your own hands, you can proceed from available materials and components. For example, cans, pans, and any cylindrical metal containers can be used as a body. Any pipe that is resistant to high temperatures is suitable as a “smoke pipe” (but a metal hose is best). Without a fan, the smoke generator also works, but not as efficiently - the natural draft is too weak and the smoking process takes longer.

Technological properties smoke are largely determined by its chemical composition. The chemical composition of smoke depends on many factors, among which the most significant are: temperature of smoke formation; generation method; type of wood - wood moisture content; wood particle size; air access to the smoke generation zone; smoke transportation.

Wood requires heat to decompose and produce smoke. In the practice of smoking production, heat for generating smoke is obtained either by burning part of the wood used, or by supplying it from the outside.

The process of wood pyrolysis was studied on a laboratory device and presented in the form of a so-called “smoke thermometer” (Fig. 52).


Rice. 52. Smoke thermometer

When the wood temperature increases to 120 °C in upper layers sawdust, the formation of droplets of condensing water was observed. When the temperature reached about 185 °C, the color of the sawdust changed and a barely visible “thin” fog was observed. According to the researchers, this fog had a pungent odor, but could hardly be called smoke. For the first time, real smoke appeared in the temperature range of 220-300 °C.

The observed smoke formation continued up to a temperature of 500 °C, and the sawdust was completely charred. No smoke formation was observed in the combustion zone.

Here the burning of charcoal was observed, which had lost the ability to release gas. Smoke appeared near the combustion zone in wood that was not yet burning, but sufficiently heated.

Numerous studies of the influence of wood pyrolysis temperature on the chemical composition of smoke have led to the conclusion that the maximum yield of such chemical substances, like phenols, acids and carbonyl compounds, occur at temperatures of 550-650 °C.

At higher generation temperatures, as well as at lower ones, the content of phenols, acids and carbonyl compounds in the smoke is noticeably reduced.

The specified (optimal for given conditions) temperature when obtaining heat for the decomposition of wood due to combustion is ensured, as a rule, by changing the air supply to the combustion zone. With an increase in air supply, the temperature in the wood pyrolysis zone rises, and vice versa, limiting the air supply leads to a decrease in temperature.

It is easier and more accurate to regulate the temperature of smoke production, and therefore its chemical composition when using an external heat source for heating. In this case, the temperature is maintained and regulated by automation devices.

Examples where the heat required for pyrolysis is not generated by the combustion of charcoal, but is supplied externally, include heating superheated steam or using frictional heat. In practice, two similar smoke generators have been used, namely friction and steam. Friction operates at a pyrolysis temperature of about 380 °C, steam - from 320 to 380 °C. Smoke formation occurs when one or the other method is used in the lower temperature range required for lignin pyrolysis. At these temperatures, lignin is a source for the formation of flavoring components of smoke, such as phenols, and decomposes completely.



With many years of experience in the production of smoked fish products, preference has been given to wood when generating smoke. hardwood trees. The finished products, when processed in smoke from this wood, have high quality indicators, in particular a pleasant taste and smoky aroma. This fact is undoubtedly associated with the chemical composition of the smoke used and its condition.

It has been established that in the smoke generated when burning hardwood (oak, beech), the content of volatile acids is significantly higher than in the smoke generated from coniferous wood.

There is a difference in the structure of lignin in softwood and hardwood. The main components of phenolic compounds in smoke from soft wood is guaiacol, from hard wood - a mixture of guaiacol, syringol and its para-component derivatives. Hence the significant differences in the flavoring effect of these two types of smoke.

In the smoke from coniferous wood (spruce, pine) it was noted high content resinous substances and carbonyl compounds. Products treated with this smoke, as a rule, have an intense surface color and a pronounced resinous aroma.

Experimental work using an aerosol filter and a cascade impactor showed that the mass concentration of smoke smoke generated from birch sawdust is three times less than the mass concentration of smoke smoke generated from beech sawdust.

It was suggested that if the smoke from beech sawdust is more concentrated in the dispersed phase, then significantly less fuel from beech will be required to smoke the same amount of fish than from birch.

In practice, when producing smoked fish products, waste from wood processing enterprises is used as fuel to produce smoke. In most cases, this is a mixture of sawdust from various woods, most often hardwood.

Humidity of fuel (sawdust)

Research has been carried out on the influence of the moisture content of the material (sawdust) on the smoke formation process. The experiments considered sawdust with humidity levels of 0, 10, 20, 30, 40, 50% and smoke formation temperatures of 300, 500 and 700 °C. The time of onset of formation and the duration of smoke emission were recorded when burning the studied sawdust with different humidity levels and after cooling the mass of the remainder of the burnt wood. It has been established that at temperatures of 500 and 700 °C, complete decomposition of wood occurs and the mass of charcoal formed is almost the same for these temperatures.

In both cases, about 75% of the dry wood mass turns into smoke. At the same time, at a temperature of 300 °C, incomplete smoke formation was noted.

With subsequent heating for 1 - 2 hours, the mass of charcoal decreased, but did not reach the residual 25% that was observed at temperatures of 500 and 700 °C. Based on the work carried out, a number of conclusions were made. Firstly, water delays the onset of the smoke formation process, but this does not in any way affect the total amount of smoke produced at sufficiently high temperatures. Secondly, water evaporated from sawdust partially displaces oxygen from the combustion zone, as a result the temperature of the fire decreases and more smoke is produced. In addition, additional heat is required to evaporate water from sawdust, which also leads to a decrease in temperature in the smoke generation zone. Thirdly, a decrease in the pyrolysis temperature during the development of smoke affects chemical composition smoke and, as a result, on its sensory properties. Fourthly, the increased moisture content in sawdust leads to significant humidification of the smoke, reducing its moisture capacity.

When studying the effect of fuel moisture on the dispersed composition of smoke smoke, it was noted that the mass concentration of smoke at a given temperature decreases with increasing relative humidity of sawdust.

The air entering the combustion zone during the formation of smoke has important, since to some extent it affects the chemical composition of the smoke. As air access increases during a certain period, an increase in the content of phenols is observed. The concentration of phenols, acids and carbonyl compounds increases with increasing proportion of decomposed wood and the amount of air supplied. With a large amount of incoming air, the generated smoke smoke contains an increased amount of resins and the content of phenols in it decreases.

In most modern smoking enterprises, smoke for fish processing is obtained in special devices - smoke generators, which are usually located at some distance from the smoking installations. In these cases, the centralized supply of smoke to the smoking chambers is carried out through chimneys. Transportation of smoke is reflected in its chemical composition; in this case, the degree of changes that occur depends on the distance of the generating device to the smoking chamber; changes in the cross-section of chimneys; changes in smoke temperature. When transporting smoke, accompanied by a decrease in temperature, a change in the ratio between the content of smoking components in the dispersed phase and the dispersion medium is observed. Main part chemical compounds concentrated in the dispersed phase.

During the movement of smoke, coagulation of particles and deposition of the latter on the walls of the air ducts are observed, and a significant part of the resinous substances is deposited in the air ducts. As a result, the total content of smoking components in the smoke is reduced.

Since chemical compounds are distributed between the dispersed phase and the dispersion medium, the question of where more of them are located and which of the above smoke phases plays a decisive role in smoking is important.

An increase in relative humidity at the same temperature leads to an increase in the amount of phenolic compounds in the dispersed phase, and at a relative humidity of about 90 % Almost all phenols are concentrated in it. An increase in the temperature of the working environment promotes the redistribution of phenols between phases - part of the phenolic compounds from the dispersed phase passes into the vapor phase. However, even with maximum permissible temperatures cold smoking process (30-34 °C) the content of phenols in the vapor phase with a relative humidity of 20% did not exceed 50-55 % from their total content in the smoking environment.

Thus, it has been established that during cold smoking the phenolic components of smoke are mainly in the dispersed (droplet-liquid) phase. This is partly due to the fact that the boiling point of phenolic compounds is in the range of 182-260 °C.

Under hot smoking conditions at working environment temperatures from 80 to 140 °, the picture changes. Studies of model vapor environments regenerated from smoking products have shown that the bulk of smoke components of smoke in the lower temperature range are in the vapor phase. With an increase in temperature from 120 to 140 °C in the dispersed phase total quantity phenols, acids and carbonyl compounds decreases from 10 to 25% depending on the type of drug used and its chemical composition.

Negative factors smoke smoke and ways to eliminate them. Under the influence of individual components of smoke, in particular carbonyl compounds, the content of amino acids in the product, and especially lysine, decreases, resulting in a decrease the nutritional value products.

Among the carbonyl compounds in smoke, formaldehyde dominates. Free formaldehyde is one of the possible reasons formation of cancerous tumors. Nevertheless, it has been proven that the human body is a system sufficiently protected from the effects of this substance, and its content in food is permissible up to 50 mg per 1 kg.

The main attention of specialists when studying issues related to smoke smoking is focused on finding ways to reduce the penetration of harmful chemical compounds into the processed products. In this area, researchers have achieved certain positive results. Thus, products with a reduced content of PAHs were obtained by using smoke generated under strictly defined conditions of pyrolysis and oxidation of volatile thermal decomposition products during the smoking process. As a result of numerous studies, it has been reliably proven that least amount polycyclic aromatic hydrocarbons contains smoke generated at temperatures of 300-400 o C.

Benzpyrene is concentrated mainly in the dispersed phase of smoke containing heavy resins. Separation of the dispersed phase and the use of exclusively steam media for smoking made it possible to significantly reduce the ingress of benzopyrene into the product.

The concentration of PAHs in smoked food products is significantly reduced when processed with chilled or filtered technological smoke. Studies of the composition of smoking media have confirmed that cooling promotes the condensation of high-boiling carcinogenic components of smoke, as well as coagulation and sedimentation of large particles of the dispersed phase containing benzopyrene.

Filtration is one of the simplest and most common methods of partial purification of smoke from undesirable compounds, based on the removal of particles from the smoke-air mixture large sizes. Thus, one of the proposed methods for reducing PAHs is the use of electrostatic air filter containing an ionizing section. Patent descriptions also contain recommendations for reducing PAHs in smoke using a cyclone. Filters are also used for these purposes mechanical removal from the smoke of resinous substances, but placing such a filter along the smoke path creates additional heat losses during hot smoking and contributes to an increase in wood fuel consumption.

Sensory evaluation of smoked products prepared with regular smoke compared to products processed with filtered smoke showed that they were similar in quality, but products smoked with filtered smoke were less intensely colored. Removing part of the dispersed phase during filtration leads to a decrease in the content of all smoke components, including aromatic and color-forming ones.

Steam smoked products are characterized by a low concentration of carcinogenic compounds, but they differ significantly in their organoleptic characteristics from the corresponding smoked products, in particular in the intensity of color and expressiveness of aroma, which are more pronounced during smoke smoking.

Most units for generating smoke include systems for partial purification of smoke from undesirable components. An example of a fairly effective method for purifying smoke is a device of the so-called water-inertial type, proposed by the Azcherryba Central Design Bureau (Fig. 53).

Thanks to inertia and effective contact with water, heavy smoke particles (soot, ash, tar) remain in it. Running water carries away particles of soot and ash, and the resin settles to the bottom of the device and is periodically removed through a hatch into a special container.

The methods and techniques listed above that help reduce the concentration of polycyclic aromatic hydrocarbons in smoked products do not lead to a noticeable decrease in nitrosamines, since one of the main sources of their formation in the product, nitrous oxide, is in the vapor phase of smoke, which does not undergo noticeable changes during the process. cleaning in smoking installations.

No less important issue associated with the use of smoke during smoking is the protection environment from air polluting smoke emissions containing a large number of organic substances.

Rice. 53. Cleaning device for smoke generator N-10-ID2G-1;

1 - purified smoke output; 2 - fitting for connection to the water supply network; 3 - bottom of the device; 4 - central pipe; 5 - circular wall; 6 - a partition dividing the device into two compartments; 7 - drain tray; 8 - Luke; 9 - elbow

Amount emitted into the atmosphere organic compounds reaches 2 g/m 3 during cold smoking, and 10 g/m 3 during hot smoking.

Currently, methods of adsorption, absorption, high-temperature and catalytic combustion, liquid-phase oxidation, electrostatic deposition and combined methods are used to purify smoke and gas emissions from industrial enterprises.

In order to prevent environmental pollution from emissions from smoking industries, methods such as sedimentation of the dispersed phase of emissions in a high-voltage electrostatic field, catalytic and high-temperature combustion are most often used and recommended.

Of significant importance when assessing the effectiveness of a particular cleaning method is, in addition to the cost of the devices and their reliability in operation, the possibility of side effects and operating costs.

Afterburning of smoke emissions is the most effective way neutralization, which achieves a high degree of purification from toxic substances. The process can take place at a temperature of about 500 °C (catalytic afterburning) or 750 °C (thermal afterburning), resulting in the formation of water vapor and carbon dioxide. Regular fuel oil or gas is used as fuel in afterburning devices. It should be taken into account that when using fuel oil as fuel, sulfur dioxide is formed. If installations are used to burn smoke of relatively low density (density), then the amount of sulfur dioxide formed may be higher than the amount of organic carbon burned. In addition, at present, the use of these cleaning methods is becoming economically unprofitable due to the high energy (fuel) consumption of afterburning devices.

The method becomes economical if the combustion chambers of existing thermal units, such as boilers, are used for afterburning. However, thermal neutralization is complicated by the presence of tar substances in the emitted gases. The accumulation of resin disrupts the aerodynamics of chimneys and the operation of control and burner devices.

In Fig. Figure 54 shows an installation for thermal neutralization of smoke emissions containing resin. Smoke emissions from smoking stoves 1 and systems exhaust ventilation 2 pass through the resin pre-separation tank 3, reducing resin deflection in the fan 4. Gas duct 5 also serves as a condenser and is laid in the direction of the resin collector 10. The flue gases are then supplied by a blower 6 into the air path of the oil-gas burner 7, located in the boiler furnace. The separated resin is periodically heated by a coil 9 to reduce the viscosity of fuel oil, which is pumped 8 is supplied to the liquid path of a gas-oil burner for combustion in the same way as liquid fuel.

Rice. 54. Installation for thermal neutralization of exhaust gases:

I - smoking oven; 2 - suction channels of the exhaust ventilation system; 3 - resin pre-separation capacity; 4 - fan; 5 - gas duct; b - fan supplying gases to the burner; 7 - gas-oil burner; 8 - fuel oil pump; 9 - resin heating system; 10 - resin collector

Rice. 55. Circulation system of the Atmos-2000 smoking installation:

1 - smoking chamber; 2 - shower system; 3 - exhaust air outlet; 4 And 15 - valves for regulating temperature and humidity of the working environment; 5 - working medium circulation fan; 6 - air supply duct to the smoke generator; 7 - smoke generator; 8 - air supply to the combustion zone of the smoke generator; 9 - throttle valve; 10 - air supply bypassing the sawdust combustion zone; 11 - electric ignition of sawdust; 12 - supplying smoke to the chamber; 13 - condensate drain; 14 - working environment heating system

Reducing environmental pollution is also facilitated by a more complete use of smoke in a smoking installation due to its recirculation and the creation of closed (circulation) systems. Example practical application closed system The Atmos-2000 installation can serve (Fig. 55). With this system of organizing the smoking process most of The air necessary for the occurrence of chemical reactions during sawdust smoldering is taken from the working environment of the smoking chamber. Thanks to this, the amount of waste smoke during conventional smoking is reduced by 1/10.

Smoking products has been practiced by humanity since ancient times. This is due to the fact that this way you can preserve perishable products that acquire wonderful taste qualities. Over the past few centuries, people have made great strides forward in terms of the technologies used, but they also continue to smoke meat and fish. Most main role During smoking, the smoke from the wood of fruit trees plays. It is this that gives the finished product a unique aroma. There is no need to worry about purchasing a smokehouse, since it is quite easy to build a smoke generator for smoking with your own hands. There are many designs that can be repeated even by people inexperienced in such matters.

Types and technologies of smoking

There are two types, different in size and hot. They differ in the temperature at which the product is prepared. If at can reach 95 0 C, then when cold it should not be higher than 35 0 C.

Hot smoking

The method is that the products are placed in a container, where they are treated with hot smoke, baked and smoked at the same time. The process is quite fast, usually takes several hours, and the end result is an unusually tender, aromatic and tasty product. However, such products cannot be stored for a long time, just a couple of days in the refrigerator.

Making a smoking device

How to make a smoke generator this way? Yes, very simple. In this case, the smoke generator and smoking chamber can be combined. Because no cooling of the smoke is required. A metal bucket with a lid, a large saucepan or a barrel will do. Sawdust or wood chips are poured onto the bottom, and the smokehouse is placed on a fire or electric stove.

Smoke emission and heating of the raw materials occur simultaneously. If the smokehouse is well sealed, or when a water lock is used, the smoking process does not require special control. All you have to do is pick temperature regime, in which the food will not burn.

Cold smoking

This method involves both more thorough preparation of the raw material and longer treatment with smoke. This is due to the use of cooled smoke, the temperature of which should not exceed 35 0 C. Before placing the products in the smokehouse, they must be well salted and then dried. The use of wet raw materials for cold smoking is unacceptable, because the smoke will dissolve in moisture, and the cooking process will take much longer.

Nuances when smoking

The cold smoking process is much more multifaceted. There are a lot of nuances, reservations, and a lot depends on the skill of the “chef.” Any of the technological operations can be reproduced in different ways, and each time the result will be different from the previous one.

Even a smoke generator made with your own hands for smoking can significantly affect the taste of products. Various designs smoke is produced with different intensities, and accordingly, smoking will take place differently. As at the dawn of mankind, the most important thing in smoking is the smoke. It is to him that the products owe their golden brown crust and unique taste. Let's look at this component in a little more detail.

How to get smoke

The smoke itself, as mentioned above, is obtained from chips or sawdust of certain types of wood. As a rule, these are fruit trees: cherry, apple, pear. But you can use both alder and willow for this. The smoke generator for cold smoking can handle any material. The taste, smell, and color of the resulting smoked meats depend on the type of smoke chosen. Here everyone decides for themselves which wood to choose, and, as a rule, settles on one thing.

Smoke generator designs

Homemade smoke generators for smoking vary in design, but they are all very simple to replicate. They are divided into two large groups depending on what heating source is used: electricity or open fire. The simplest smoke generator for smoking, made by yourself, is a small metal box with an outlet, which is put on to remove the smoke. Sawdust is placed in it and it is placed on an open fire. When exposed high temperature the wood chips begin to slowly smolder without access to oxygen. Despite their simplicity, these types of devices are quite difficult to use. Since the smoking process can take several days, and sometimes even several weeks, it is quite difficult to control the release of smoke, including its continuous supply.

Such designs do not allow you to quickly add sawdust and control the temperature of the smoke in the smokehouse. The smoke generator for cold smoking, having electrical element. In this case, you can control both the temperature of the incoming smoke and the process of igniting the sawdust - for this purpose the the electronic unit management. Structurally, it is the same small box with an outlet for a pipe, but inside it has a spiral or heating element from an electric stove. After a certain time (usually a couple of hours), the heating element heats up and the sawdust begins to smolder, releasing smoke. There are smoke generators made according to the muffle principle. In this case, a nichrome spiral is wound onto it. Each new turn is insulated with fiberglass, and this entire structure is covered with tin on top. This solution makes it easy to very quickly heat sawdust to a temperature at which they begin to smolder.

The muffle also maintains the temperature for some time, allowing smoke to be released after the heat is turned off. In this case, a temperature sensor can be built into the smokehouse itself, which will turn off the heating element when it reaches maximum temperature 35 degrees. This design does not require the constant presence of a person to control the process; it is enough to simply sometimes add sawdust to a homemade smoke generator for smoking. These are the most advanced devices for producing smoke. If planned constant use smokehouses, then such smoke generators are the best choice.

How to cool smoke

After the smoke is obtained, it must be cooled to the required temperature. It can be done different ways, the most popular of which is laying the chimney in a tank with cold water. Typically, in this case, a smoke generator for smoking, made with your own hands for an open fire, is used. The chimney can also be buried in the ground, which can also cool the smoke very well. There are designs where the chimney is represented by a trench in the ground, covered on top to prevent smoke from escaping.

Passing along this path, it cools down, and smoking takes place in a normal cold mode. This method of cooling smoke is used in hiking conditions, where finding a corrugated pipe and a large container for water is very difficult. Smoke generator for smoking (assembled with your own hands) with electric heating element, as a rule, does not require smoke cooling. The temperature sensor is capable of turning off heating when a critical temperature is reached, maintaining the smoking process and not overheating the raw materials.

Smoking smoke is formed as a result of complex reactions of thermal decomposition and oxidation of the main parts of wood - cellulose, lignin and hemicellulose.

The saturation of smoke with organic compounds depends on the completeness of their oxidation, which is a function of the amount of air supplied to the combustion zone, the combustion temperature and the rate of removal of volatile combustible substances from the fireplace. The maximum yield of volatile organic compounds formed during the thermal decomposition of wood is observed at a temperature of about 300°. At approximately the same temperature (280-350°), the smoke contains the maximum amount of the most important smoking components.

The quality of smoking smoke also depends on the type and condition of the wood. The best smoking smoke is produced by using sawdust from dry hardwood, which burns slowly and releases many volatile organic compounds, including aromatic and coloring compounds. Soft woods are also suitable for smoking, as well as some coniferous trees, but they are less acceptable because they burn quickly, releasing a lot of heat and soot. In this regard, coniferous wood should be used for smoking provided that smoke is generated outside the smoking chamber and cleaned.

An external sign of good smoking properties of smoke is its light color. Light smoke is produced by slow surface burning of dry wood. The smoke from raw wood during natural combustion is dark, heavy, and has reduced technological properties.

When producing smoke in smoke generators, in which the wood can be pre-dried, its moisture content is less important.

The interaction of smoke smoke with the product is due to a number of its properties as an aerosol system. The smoke aerosol consists of a dispersion medium (gas and vapor substances) and a dispersed phase - colloidal particles, mainly of a viscous liquid and having a spherical shape with an average radius of 0.08-0.1 μm.

Vapors are crucial for smoking organic matter and their colloidal particles present in the smoke in a ratio of 1: 10. At the same time, more volatile smoke components predominate in the vapor state, and less in the form of particles volatile compounds. The structure and properties of smoke (the ratio of various phases, the degree of dispersion of colloidal particles, the presence of soot particles in the smoke, etc.) are determined by many factors (conditions for the formation and cooling of vapors, the degree of dilution with air, etc.). A technologically superior smoke is obtained by rapidly cooling the steam-gas mixture formed during the combustion of wood and diluting it with a significant amount of air.

The deposition of smoke smoke on the product is directly dependent on the concentration of smoke components and the speed of approach of colloidal particles to the product. Smoke particles move not only under the influence of external forces (movement along with the environment, in electric field etc.), but also under the influence of gravity, Brownian motion and temperature gradient.

Smoke, which has a high degree of dispersion, is deposited mainly under the influence of Brownian motion and temperature changes. Smoke with enlarged particles (due to coagulation) is deposited mainly under the influence of gravity and turbulent movement.

When deposited on dry surfaces and under the influence of kinetic forces (deposits on the sticky surface of the product), the influence of the particle phase is felt. The deposition of smoke on a wet surface is associated primarily with the condensation of vapors that are in a state of mobile equilibrium with liquid particles. In this case, the deposition rate is determined partial pressure vapors of smoke components and it increases with increasing temperature, as well as increasing speed of smoke movement at the deposition surface and decreases as the product dries. In smoking practice, smoke of varying densities is used: from 0.1 g/m 3 (very rare smoke) to 3 g/m 3 (thick smoke).

The smoke density can be determined optically. Of these, the most suitable method is based on measuring the intensity of light passing through the smoke. However, when determining the density of smoke in this way, the ratios are not taken into account smoking substances in a dispersion medium and dispersed phase.

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5. Filtration of smoke through water

One of the common methods of air purification, which allows the removal and use of retained substances, is filtering through a liquid medium. The method is quite effective both for capturing significantly concentrated gases and for condensing vapors and absorbing solid particles. The mechanism of air purification when passing through water is not fully understood. It is a combination of several processes, one of which is diffusion at the boundary of contact of media, the other is air circulation due to washing with water. In addition, air pollution, based on its “behavior” in the atmosphere and when mixed with liquid, can be divided into 4 main groups. These are "gases", vapors of water-soluble substances, vapors of insoluble substances and solid particles.

Here, “gases” mean compounds that are not capable of condensing into liquid state(liquefy) at temperatures close to room temperature (-5ºС and further). These include hydrogen sulfide, ammonia, nitrogen, oxygen, chlorine, carbon dioxide, carbon dioxide, sulfur dioxide and other gases. Vapor will mean a suspension of microscopic droplets or individual molecules of substances in the air that can condense at temperatures close to room temperature. These are vapors of water, alcohols, fats, carboxylic acids, etc. Solid particles - dust, soot, and so on. Let's consider mixing each of these groups with water.

The bubble, passing through layers of water, is intensively washed by the liquid. As a result, layers of air adjacent to the air-water interface are constantly moving. The layers of these media located directly at the interface are intensively mixed. Light gas molecules are much more mobile than polyatomic organic molecules of impurities, and even more so than solid particles, which are massive in comparison with them. Therefore, with intense movement, molecules consisting of a small number of atoms have a high chance of changing direction when meeting the interface and heading back into the bubble. More massive molecules and particles, approaching the interface, cannot quickly change direction, and as a result, they go into a denser and more viscous medium - water. Vapors behave like solid particles. While in a bubble, some of the microscopic droplets merge with each other due to the movement of layers of air. When colliding with the surface of water, droplets of soluble substances merge with it and dissolve in the liquid. For microdroplets of water-insoluble substances, collision with the interface leads to condensation. The condensed droplets rise with the bubble and combine near the surface of the water, forming oily spots and waxy “icebergs.” The effectiveness of this cleaning depends on the ratio of the volume of the bubble to its surface area, as well as the rise time.

Rising closer to the surface, the bubble increases in volume, since with decreasing depth, the pressure of the surrounding water drops. In other words, the ratio of the volume of the bubble to its area increases. However, the internal energy of a compressed gas, other things being equal, increases with increasing pressure. Consequently, the energy of motion of gas particles is higher. Thus, the probability of particles transferring from gas to water for a bubble under higher pressure will be higher. Therefore, it is desirable that more bubbles form, but their initial volumes are extremely small, and the depth of rise is also greater. This can be achieved by blocking the end of the tube and making many small holes in its lower part, located relatively far from each other. Last condition It is necessary that, when approaching the surface, the bubbles do not merge.

A similar cleaning method has long been used by Asian hookah smokers. Tobacco smoke through the tube it enters a vessel filled with water, passes through the water, and is partially purified. Another tube comes from the neck of the vessel, with the help of which the smoker inhales.

Passing smoke through water reduces the amount of tar, tar and other potentially carcinogenic substances. Studies have shown that filtering smoke through water in a hookah reduces the content of: nicotine, phenols by 90%, fine particulate matter by 50%, benzopyrene, polycyclicene aromatic hydrocarbons. There is a reduction in the carcinogenic potential of smoke that has crossed the water compared to smoke that has not undergone such filtration. Hookah smoke, devoid of substances such as acrolein and aldehydes, unlike cigarette smoke, does not irritate the mucous membranes of the throat or nose of smokers and persons located near the hookah.

However, it has been found that the level of cotonine in the blood is increased compared to cigarette smokers. On this basis, the researchers concluded that smoke, passing through water, loses the concentration of only some of its components, while others remain approximately the same composition.

As it becomes saturated with impurities, the ability of water to dissolve new portions gradually decreases. When filtering smoke, substances that are solvents for certain organic compounds are concentrated in the water. For example, alcohols and acids dissolve fats, some hydrocarbons are dissolved by aldehydes and ketones. However, the mutual combination of all these compounds can reduce the solubility of compounds of other classes. Therefore, regardless of the emerging composition, the key to high efficiency Water filtration is the periodic replacement of water.




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