Snail exhaust ventilation. Where will the snail hood be used? Exhaust systems using radial fans

Fans used for indoor air exchange have different designs. Depending on the operating conditions and assigned tasks, axial or radial devices capable of operating in different modes can be installed. Their purpose and features are optimally suited for a particular area ventilation system. Let's take a closer look at the question.

In common parlance called "snail", are devices with multidirectional axes of suction and discharge of air flow. In contrast, where the air stream moves parallel to the axis of rotation of the impeller, in operation radial fans centrifugal force is used, which is why such devices called more and centrifugal.

The working body of such a fan most closely resembles a squirrel wheel. The blades, located parallel to the axis of rotation, capture portions of air and, rotating, forcefully push them out in a perpendicular direction. This is the effect of centrifugal force. The fan housing has a specific snail shape, thanks to which all the individual flows ejected by the impeller blades are collected into a single elastic flow rushing outward from the outlet pipe. Because of this, a vacuum is formed, which is immediately filled with outside air entering through the suction hole. It is located on the front side of the case. Thus, it turns out that the suction and discharge of the flow are carried out in a transverse direction to each other.

Peculiarities

The main feature of the cochlear fan is its ability to create high outlet pressure. Axial structures have high performance, but most of them are not capable of creating pressure. Therefore, to work with complex system air ducts with high aerodynamic resistance, only “snail” type is suitable.

READ ALSO: Forced ventilation- in a private house, apartment and garage

Based on the amount of pressure created, they are divided into three categories:

Each category of fans is used in appropriate conditions and performs tasks that require specific operating parameters.
Second, no less important feature“snail” fans is the ability not only to create pressure, but also to produce the opposite effect - create a vacuum. This is the versatility of the snail's action - it can equally effectively work both on discharge and on suction. Such capabilities significantly expand the scope of use of snail fans, and, in combination with high operating pressure, allow them to perform additional features. For example, there are so-called , capable transport bulk materials through the air duct system. In addition, the ability to create negative pressure is used in various industrial applications. technological installations for removing combustion products (smoke fans).

The most popular models of snail fans are VR and CC (Fan Radial And Fan Centrifugal). Some complication of the situation in this regard is that there are no special rules for naming fans and each manufacturer has the right to name their products as they see fit. Therefore, models of “snail” fans often appear that have exactly the same parameters, but different designations.

Unity of standard sizes is necessary for the possibility of connection to other equipment -, etc. In this regard, the situation is more successful; the fans fit completely into adjacent elements of the system. If models and elements of different standard sizes are used, then appropriate adapters are used to pair them.

Types and scope

Scroll fans have different standard sizes, which allows you to select a device that best suits the operating parameters to the requirements of the system. All samples of “snails” have numbers indicating the diameter of the impeller in decimeters. For example, №5 means that the impeller has 0.5 m in diameter.

The use of "snails" is very widespread. They are found in almost all ventilation systems, in production lines, and are used for dust extraction, transportation of bulk products in grain elevators, in woodworking, for removing metal shavings, etc. Widely used as exhaust fans , since there are simply no other structures capable of performing such work.

Expert opinion

Heating and ventilation engineer RSV

Fedorov Maxim Olegovich

A “snail” fan is capable of creating a vacuum in the air duct system covering one or several rooms and thereby organizing the effective exhaust of exhaust air from them.

In addition, the possibility of supplying air ducts to the place where dust directly occurs, emission harmful substances, suspension. This allows you to quickly remove unwanted components, preventing them from spreading throughout the entire room or building.

Fan VR 100-45 (VTsP 7-40)

As a sample dust fan, used to remove bulk materials or unwanted air suspensions, consider the BP 100-45 fan. Its analogues are the following models:

Creating high-density airflow is possible in several ways. One of the effective ones is a radial type fan or “snail”. It differs from others not only in shape, but also in its operating principle.

Sometimes an impeller and a power unit are not enough to move air. In conditions of limited space should be used special kind design of exhaust equipment. It has a spiral-shaped body that acts as an air channel. You can make it yourself or purchase it already finished model.

To form the flow, the design includes a radial impeller. It connects to the power unit. The wheel blades have a curved shape and create a discharged area when moving. Air (or gas) enters it from the inlet pipe. When moving along the spiral body, the speed at the outlet increases.

Depending on the application, the centrifugal fan volute can be general purpose, heat-resistant or corrosion-resistant. It is also necessary to take into account the amount of air flow created:

low pressure. Area of application: production workshops, household appliances. The air temperature should not exceed +80°C. Mandatory absence of aggressive environments;
average pressure value. It is part of exhaust equipment for removing or transporting small fraction materials, sawdust, grain;
high pressure. Forms an air flow into the fuel combustion zone. Installed in many types of boilers.

The direction of movement of the blades is determined by the design, and, in particular, by the location of the outlet pipe. If it is located on the left side, the rotor should rotate clockwise. The number of blades and their curvature are also taken into account.

For powerful models you need to do it yourself solid foundation with housing fixation. The industrial installation will vibrate strongly, which may lead to its gradual destruction.

First of all, you need to decide functional purpose centrifugal fan. If it is necessary for ventilation of a certain part of the room or equipment, the housing can be made from scrap materials. To complete the boiler, you will need to use heat-resistant steel or make it from stainless steel sheets yourself.

First, the power is calculated and the set of components is determined. The best option The snail will be dismantled from old equipment - an extractor hood or a vacuum cleaner. The advantage of this manufacturing method is the exact match between the power of the power unit and the body parameters. A snail fan can be easily made with your own hands only for some applied purposes in a small home workshop. In other cases, it is recommended to purchase a ready-made industrial-type model or take an old one from a car.

Procedure to make a centrifugal fan with your own hands.

Calculation overall dimensions. If the device will be installed in a confined space, special damper pads are provided to compensate for vibration.
Manufacturing of the body. In the absence of finished design You can use plastic sheets, steel or plywood. In the latter case, special attention is paid to sealing the joints.
Installation diagram of the power unit. It rotates the blades, so you need to choose the type of drive. For small structures a shaft is used that connects the motor gearbox to the rotor. In powerful installations, a belt type drive is used.
Fastening elements. If the fan is installed on the outer casing of, for example, a boiler, mounting U-shaped plates are made. With significant power, it will be necessary to make a reliable and massive base.

This general scheme, according to which you can make a functional exhaust centrifugal unit with your own hands. It may change depending on the availability of components. It is important to comply with the housing sealing requirements, as well as ensure reliable protection power unit from possible clogging with dust and debris.

The fan will make a lot of noise during operation. Reducing this will be problematic, since vibration of the housing during the movement of air flows is almost impossible to compensate with your own hands. This is especially true for models made of metal and plastic. Wood can partially reduce background noise, but at the same time it has a short service life.

In the video you can see the process of manufacturing a case from PVC sheets:

Review and comparison of production ready models

When considering a radial volute fan, you need to take into account the material of manufacture: cast aluminum housing, sheet or stainless steel. A model is selected based on specific needs; consider an example of serial models in a cast case.

Fan device and design

Sometimes an impeller and a power unit are not enough to move air. In conditions of limited space, a special type of exhaust equipment design should be used. It has a spiral-shaped body that acts as an air channel. You can make it yourself or purchase a ready-made model.

Depending on the application, the centrifugal fan volute can be general purpose, heat-resistant or corrosion-resistant. It is also necessary to take into account the amount of air flow created:

low pressure. Area of application: production workshops, household appliances. The air temperature should not exceed +80°C. Mandatory absence of aggressive environments;
average pressure value. It is part of exhaust equipment for removing or transporting small fraction materials, sawdust, grain;
high pressure. Forms an air flow into the fuel combustion zone. Installed in many types of boilers.

The direction of movement of the blades is determined by the design, and, in particular, by the location of the outlet pipe. If it is located on the left side, the rotor should rotate clockwise. The number of blades and their curvature are also taken into account.

For powerful models, you need to make a reliable base with your own hands to secure the body. The industrial installation will vibrate strongly, which may lead to its gradual destruction.

Self-production

First of all, you should decide on the functional purpose of the centrifugal fan. If it is necessary for ventilation of a certain part of the room or equipment, the housing can be made from scrap materials. To complete the boiler, you will need to use heat-resistant steel or make it from stainless steel sheets yourself.

First, the power is calculated and the set of components is determined. The best option would be to dismantle the snail from old equipment - a hood or vacuum cleaner. The advantage of this manufacturing method is the exact match between the power of the power unit and the body parameters. A snail fan can be easily made with your own hands only for some applied purposes in a small home workshop. In other cases, it is recommended to purchase a ready-made industrial-type model or take an old one from a car.

Procedure to make a centrifugal fan with your own hands.

Calculation of overall dimensions. If the device will be installed in a confined space, special damper pads are provided to compensate for vibration.
Manufacturing of the body. If there is no ready-made structure, you can use plastic sheets, steel or plywood. In the latter case, special attention is paid to sealing the joints.
Installation diagram of the power unit. It rotates the blades, so you need to choose the type of drive. For small designs, a shaft is used to connect the motor gearbox to the rotor. In powerful installations, a belt type drive is used.
Fastening elements. If the fan is installed on the outer casing of, for example, a boiler, mounting U-shaped plates are made. With significant power, it will be necessary to make a reliable and massive base.

This is a general scheme according to which you can make an exhaust functional centrifugal unit with your own hands. It may change depending on the availability of components. It is important to comply with the requirements for sealing the housing, as well as to ensure reliable protection of the power unit from possible clogging with dust and debris.

The fan will make a lot of noise during operation. Reducing this will be problematic, since vibration of the housing during the movement of air flows is almost impossible to compensate with your own hands. This is especially true for models made of metal and plastic. Wood can partially reduce background noise, but at the same time it has a short service life.

In the video you can see the process of manufacturing a case from PVC sheets:

Review and comparison of production ready models

A snail fan is one of the most popular devices that are used to create air flow with high densities. This hood has its own characteristics, design nuances and operating principle that distinguishes the snail from other systems.

Before you assemble a highly efficient snail fan with your own hands, you should learn about the features of this device and its design.

To carry out forced air movement, sometimes you can get by with an impeller and a power unit that will rotate the working element;
If space is limited, but an exhaust unit is absolutely necessary, specialized equipment comes to the rescue;
The cochlea is a body made in the form of a spiral;
The mission of the corps is to carry out the tasks of the air channel;
Do-it-yourself snails are quite popular, but when there is no time to assemble or lack the appropriate skills, objectively the best solution will be the purchase of finished equipment;
To create an air flow, a radial component - a wheel - is located inside the fan structure;
This radial piece of equipment connects to the power plant;
The blades on the impeller are curved, which allows them to create a discharged area when they move;
The inlet pipe of the structure serves to supply air or another medium;
Due to the movement along the spiral casing, the speed of air exiting through the outlet opening increases noticeably;
Coil fans come in heat-resistant, corrosion-resistant and general purpose;
The movement of the volute fan blades depends on the design of the equipment. Special attention attention should be paid to the location of the outlet pipe. If it is on the left, then the rotor should rotate clockwise, or vice versa;
When choosing or assembling a snail with your own hands, you need to take into account how many blades are used and what their curvature is.

Created air flows

Planning to assemble it yourself homemade unit or buy a ready-made volute-type exhaust hood, you should definitely take into account the characteristics of the air flows created. Namely, you should be interested in the flow value, on which the scope of application of the snail largely depends.

Low pressure. Low pressure air flows are widely used in production workshop equipment and layout household appliances. The air temperature here is not allowed to exceed 80 degrees Celsius. Also, low-pressure snails are not adapted to work in aggressive environments.
Average pressure. Medium-pressure scroll fans are most often found in the design of an exhaust system used for transportation and removal of fine materials. A striking example can be called grain and sawdust removal.
High blood pressure. High-pressure volute hoods form air flows that flow to the combustion zones various types fuel. Boiler equipment, working on different types fuel, is equipped with high-pressure volutes.

A volute, or centrifugal fan, requires a reliable base. The housing must be properly fixed so as not to create vibration. Industrial units are characterized by increased vibration. If this phenomenon is not prevented, the device will gradually fail.

Do it yourself

Building a scroll fan is not the most difficult thing if you decide to take on a homemade unit with your own hands.

Functional purpose. To equip a part of a room, a small area or equipment with a ventilation system, the housing can be assembled from scrap materials. If this is a centrifugal unit that will generate air flows to ensure the operation of boiler equipment, then the body is made with your own hands based on stainless steel or heat-resistant metal.
Power. This parameter directly depends on the functions that the centrifugal unit will perform. Many home craftsmen use snails removed from old equipment, ventilation systems, hoods or vacuum cleaners. By using such a unit, you guarantee an exact balance between power and body characteristics.

If you want to make a snail for domestic use, or for use inside a workshop, then you can assemble the device yourself. All other situations imply the need to use only factory-proven, proven snails.

To assemble an effective homemade snail fan with your own hands, you will need to complete the following tasks:

Calculate the dimensions of future equipment. If this is a centrifugal unit for installation in a confined space, be sure to use damper pads. They will compensate for the vibrations generated during its operation and protect the volute from premature wear. If this is a large stationary unit, vibration protection occurs due to the weight of the equipment and its fixation;
Make a fan casing. If you do not have a ready-made box that is ideal for the fan, use scrap materials. Plastic is suitable for these purposes, plywood sheets, steel. If you decide to take sheets of plywood, make sure that during the process of assembling the structure there are absolutely no gaps and all seams are properly sealed;
Think over the diagram of the snail's power unit. Task power plant— rotate the fan blades. When choosing, consider how much power the snail has. If it is a high power centrifugal fan, use a belt drive. IN small installations it is important to use a shaft that connects the motor gearbox to the rotor;
Use fasteners. When installing a scroll fan on the outer casing of the structure, use U-shaped mounting plates. If the power of the units is impressive, then be sure to adopt a massive, durable base;
Minimize noise. A high-power volute is characterized by the fact that such a centrifugal fan emits quite a lot of noise. Objectively best way protect yourself from snail noise by assembling the equipment as efficiently as possible. After assembling the cochlea, it is problematic to compensate for the noise. The noisiest models are those whose body is made of plastic and metal. Wooden cases reduce snail noise, but are significantly inferior to their metal and plastic counterparts in terms of service life.

According to the presented diagram, you can create centrifugal exhaust devices of various power purposes with your own hands. If necessary, you can make changes to the circuit, change components, add auxiliary elements.

The most significant point when assembling a fan with your own hands is the reliable sealing of all seams in the structure and the protection of the engine itself. Over time and with use, an engine that does not have proper protection can become exposed to various debris, dust, dirt and moisture. It is no secret that this leads to wear, gradual destruction and failure of equipment.

Depending on the size and performance of such units, operating conditions will also depend: in addition to household use, many types of ventilation equipment are widely used in the industrial sector. One example of such equipment is a rounded snail hood.

A radial centrifugal fan of this type is most often installed in production premises and is used to clean the air from dust, sawdust, burning, sand and other industrial waste. A similar air treatment system can be installed in multi-storey building, for example, in ventilation shaft.

Let's understand the principle of its operation and consider the main stages of constructing a snail hood with your own hands.

Design Features

Scroll hoods differ in structure from standard fans with large blades. Air flows in such equipment move due to centrifugal force resulting from the rotation of a wheel with small specially shaped blades. The speed and power of such hoods may vary depending on the number of blades and motor parameters.

The air purification scheme in radial centrifugal hoods is quite simple: when air gets inside the hood, it begins to be sucked into the rotor, where it begins to rotate and is subject to pressure, gradually moving towards the outlet and being purified from foreign elements. General form The input and output channels resemble a snail - hence the name of such a hood.

Attention! Designs of this type are useful in that they can both suck in air and ensure its outflow.

The housing of this type of ventilation system is made of durable materials such as aluminum, brass or steel. Also available for sale plastic structures, but they are less durable and rarely operate at peak efficiency.

Since air treatment can be carried out at high temperatures, the body is treated with protective paint, chemical-resistant substances, and is also coated with polymers.

Rotational mechanisms in such a system can be single, or may include two disks with blades required sizes. Both radial and circular placement of the blades ensure high performance of the device.

Advice: For better cleaning air, purchase fans in which the blades are slightly curved rather than flat.

Despite the uniform shape, such hoods are suitable for many operating conditions, as they differ in orientation to the right or left side, and in overall dimensions. On average the diameter of the main body of such a hood can be from 25 to 150 cm.

For ease of installation for industrial purposes, many structures of this type are created modular, and fastening bolts are used to connect them. Accordingly, you can change both the angle of inclination and the details of some parts of such a design for greater efficiency: It’s better to first calculate all the parameters with specialists.

Since snails can differ from each other, you should not focus solely on size and power indicators. Familiarize yourself with their varieties - and make a choice, relying on future operating conditions.

Types of equipment

First of all, snail hoods differ in pressure indicators. Ventilation can be carried out under the following conditions:

low pressure – up to 100 kg/m2;
medium – from 100 dl 300 kg/m2;
high pressure - more than 300 kg/m2 (can reach 1200 kg/m2).

The first type of hoods is suitable for use in both industrial and living conditions. As a rule, such equipment is quite compact, so it can be installed without additional help.

Attention! Low-pressure hoods are sufficient to ensure high-quality air ventilation in the shafts of multi-storey buildings.

Medium pressure fans are used for industrial purposes. Such equipment can more easily withstand difficult conditions operation, it is equipped in accordance with the main fire and technical requirements in production.

The third option is used not only in workshops, but also in laboratories, warehouses, areas where painting is carried out, etc. They can be installed for blowing air conditioning systems or working machines, as well as for pumping air into boiler systems.

Depending on the quality and degree of wear of the structure, there are general volute hoods, heat-resistant, corrosion-resistant systems, as well as heavy-duty equipment that can withstand even explosive reactions.

In most cases, snail-shaped air ventilation systems are used to remove pebbles, wood and metal shavings, wood chips and other production residues from the premises. Their installation must be carried out taking into account safety and labor protection requirements.

How to make it yourself

One of the features of such snails is their different price range. The minimum price for a snail hood will be about 3 thousand, but such devices, as a rule, are not very powerful and are very limited in size. The average price of a high-quality unit will exceed 20 thousand rubles.

Therefore for household needs It is more advisable to make a homemade snail for the hood. The standard design of such a housing will consist of two parts: the engine will be located in one zone, and the blowing blades in the other.

The casing for the snail can be purchased at hardware stores. If you are going to make it yourself, purchase the motor and other parts in advance, since the dimensions will have to be adjusted. It is better to make the case from metals (for example, aluminum and steel). Plastic will be less resistant to mechanical damage, and wood will quickly catch fire in the event of a malfunction.

The fan in such a system will operate at high speed. Therefore, incorrect design of the hood can have bad consequences. Check the quality and reliability of not only the base itself and fastening mechanisms, but also the motor, impeller and fan.

The fan dimensions are selected taking into account the area and degree of contamination of the room. Industrial designs are large.

Important! When installing the motor inside the box of such a hood, make sure that the design includes cooling holes. High temperature stress on the system can lead to an explosion.

Pay special attention to the choice internal materials. Fan operation can be affected not only by temperature, but also by the power of air flow, the amount of debris and dust.

When air with large impurities is sucked in, the blades of the rotating wheel may be damaged. And in order to thoroughly clean the air, the unit must operate at high speed and under high pressure- this creates additional load on the entire internal structure. That's why it is better to choose parts made of durable materials, such as steel or aluminum.

choose the right engine size and power: take into account the maximum load on the structure, as well as the required operating speed of the hood;
When installing such a system vertically, carefully check that the fan and wheel are securely fastened: with rapid air currents they can jump off or change their location;
materials adjacent to such a hood must be fireproof, like all the parts used in its assembly;
maintain proportions between individual hood zones: V standard models offered in stores, the optimal ratio of length and width of the structure is taken into account;
If you are not sure that the assembled hood is safe, contact specialists who will check its serviceability.

note that snail hoods are rarely used in living rooms . Firstly, they take up a lot of space, and secondly, in rooms like a kitchen, the flow of polluted air can have different directions, so it is best to install such a hood in a ventilation shaft, where all the air coming from the apartment is concentrated.

The design of such structures will also play an important role in living rooms, but it is not diverse and does not always harmonize with the interior.

Advice: when placing such a hood in open conditions(outdoors) ensure that weather conditions will not affect its functionality.

Ventilation hoods can be used not only for air purification. In domestic conditions they are excellent cope with heating the room, and also affect the humidity in the room.

The cost of equipment intended for domestic and industrial needs will differ significantly, but, in any case, such units have sufficient power for full operation.

For an example of designing a snail hood, see the attached video.